Note: Descriptions are shown in the official language in which they were submitted.
CA 03006864 2018-05-29
OXYGEN REDUCTION SYSTEM AND METHOD FOR OPERATING AN OXYGEN
REDUCTION SYSTEM
Description
The present invention relates to an oxygen reduction system and a method for
operating such a system.
An oxygen reduction system of the type according to the invention serves in
particular for the controlled reduction of the oxygen content in the
atmosphere of
an enclosed area. For this purpose, the oxygen reduction system comprises a
gas
separation system for providing an oxygen-reduced gas mixture or inert gas
respectively and a system of lines which is or can be fluidly connected to the
gas
separation system and to the enclosed area in order to feed at least some of
the gas
mixture or gas provided by the gas separation system to the enclosed area as
needed.
The method or respectively system according to the invention serves for
example to
reduce the risk of and to extinguish fires in a protected room which is to be
monitored, whereby to prevent or respectively fight fire, the enclosed room is
also
or can be rendered inert to different lowered levels on a sustained basis.
The fundamental principle of inerting technology for fire prevention is based
on the
understanding that in enclosed rooms which are only entered into occasionally
by
humans or animals and containing equipment which reacts sensitively when
exposed
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to water, the risk of fire can be counteracted by lowering the oxygen
concentration
in the respective area to a value of, for example, approximately 15% by
volume. At
such a (reduced) oxygen concentration, most combustible materials can no
longer
ignite. The main fields of use of this inerting technology for fire prevention
are
accordingly also EDP areas, electrical switch and distribution rooms, enclosed
facilities and storage areas with economic goods of particularly high value.
The fire prevention effect resulting from this method is based on the
principle of
oxygen displacement. Normal ambient air is known to consist of 21% by volume
oxygen, 78% by volume nitrogen, and 1% by volume of other gases. For fire
prevention purposes, the oxygen content in the spatial atmosphere of the
enclosed
room is reduced by introducing an oxygen-displacing gas, such as, for example,
nitrogen. A fire prevention effect is known to start as soon as the oxygen
content
falls below the oxygen content of the normal ambient air. Depending on the
combustible materials within the protected room, it may be necessary to
further
lower the oxygen content to, for example, 12% by volume.
A further application example for the oxygen reduction system or the method
according to the invention is providing hypoxic training conditions in an
enclosed
room in which the oxygen content has been reduced. Such a room enables
training
under artificially simulated high-altitude conditions, also referred to as
"normobaric
hypoxic training."
A further application example is the storing of items, particularly
foodstuffs,
preferentially pomaceous fruit, in a so-called "controlled atmosphere (CA)" in
which,
among other things, the proportional percentage of atmospheric oxygen is
regulated
so as to slow the aging process acting on the perishable merchandise.
An oxygen reduction system of the type cited above is known in principle from
the
prior art. For example, printed publication DE 198 11 851 Al describes an
inerting
system which is designed to lower the oxygen content in an enclosed room to a
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specific base inerted level and, in the event of a fire, to rapidly lower the
oxygen
content further to a specific fully inerted level.
The term "base inerted level" as used herein is to be understood as a reduced
oxygen content compared to the oxygen content of normal ambient air, albeit
whereby this reduced oxygen content poses no danger whatsoever to persons or
animals such that they could still enter ¨ at least briefly ¨ into the
permanently
inerted area without any problem; i.e. without special safety precautions such
as,
for example, oxygen masks. The base inerted level corresponds for example to
an
oxygen content in the enclosed area of from 15-17% by volume.
On the other hand, the term "fully inerted level" is to be understood as an
oxygen
content which is further reduced compared to the oxygen content of the base
inerted level, one at which the flammability of most materials is already
lowered to
the extent they can no longer ignite. Depending on the fire load within the
relevant
area, the fully inerted level is usually at an oxygen concentration of
approximately
12-14% by volume.
In order to equip an enclosed area with an oxygen reduction system, a
corresponding inert gas source first needs to be provided in order to be able
to
provide the oxygen-reduced gas mixture or inert gas respectively which is to
be
introduced into the enclosed room. The output capacity of the inert gas
source, i.e.
the amount of inert gas which can be provided by the inert gas source per unit
of
time, is to thereby be adapted to the properties of the enclosed area, in
particular
the spatial volume and/or the airtightness of the enclosed area.
If the oxygen reduction system is employed as a (preventive) fire control
measure, it
is to be in particular ensured that, in the event of a fire, a sufficient
amount of inert
gas can be introduced into the spatial atmosphere of the enclosed area within
the
shortest time so that an extinguishing effect starts as quickly as possible.
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Although the oxygen-reduced gas mixture / inert gas to be introduced into the
enclosed area when required could be stored in a battery of high-pressure
cylinders
or similar compressed gas storage, "on-site production" of at least some of
the
oxygen-reduced gas mixture to be provided by the inert gas source has become
accepted practice, particularly because storing inert gas in batteries of gas
cylinders
or similar compressed gas storage tanks requires special structural measures.
In order to be able to "produce" at least some of the oxygen-reduced gas
mixture or
inert gas to be provided by the inert gas source on site, the inert gas source
usually
comprises ¨ in addition to a battery of high-pressure cylinders or similar
compressed
gas storage ¨ a gas separation system in which at least a portion of the
oxygen
contained in an initial gas mixture fed to the gas separation system is
separated off
so that an oxygen-reduced gas mixture is provided at an outlet of the gas
separation system.
The term "initial gas mixture" as used herein is to be generally understood as
a gas
mixture which, in addition to the oxygen component, in particular also
contains
nitrogen as well as, where appropriate, additionally gases (e.g. noble gases).
One
conceivable initial gas mixture is for example normal ambient air; i.e. a gas
mixture
consisting of 21% by volume oxygen and 78% by volume nitrogen and 1% by
volume of other gases. However, it also conceivable to use some of the spatial
air
contained within the enclosed area as the initial gas mixture, whereby fresh
air is
preferably also added to the room's spatial air content.
The gas separation system serves in particular to maintain a reduced oxygen
content at the corresponding level in the spatial atmosphere of an enclosed
room.
The output capacity of the gas separation system; i.e. the amount of oxygen-
reduced gas mixture which can be provided per unit of time at the outlet of
the gas
separation system, is accordingly adapted in particular to the tightness of
the
enclosed area's spatial shell so that a corresponding sustaining flooding can
be
realized via the gas separation system.
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On the other hand, it is advantageous in terms of the system design to not use
or
not only just use the gas separation system for the initial lowering of the
oxygen
content in the spatial atmosphere of the enclosed area since an initial
lowering
requires a relatively large amount of inert gas or oxygen-reduced gas per unit
of
time. To be able to realize this solely with a gas separation system, the gas
separation system would have to be of correspondingly large configuration,
which is
generally not viable in terms of investment costs.
Therefore, in addition to the gas separation system, conventional oxygen
reduction
systems are usually provided with a compressed gas storage in which an oxygen-
reduced gas mixture or inert gas is stored in compressed form. The gas mixture
or
inert gas respectively stored in this compressed gas storage serves in
particular in
rapidly lowering the oxygen content in the corresponding enclosed area so as
to
quickly lower the oxygen concentration in the event of a fire. It is however
also
conceivable to use the gas mixture / inert gas stored in the compressed gas
storage
for the initial lowering of the oxygen content in the corresponding enclosed
area;
i.e. for the initial reducing of the oxygen content to a specific inerted
level.
The present invention is based on the problem posed after a conventional
oxygen
reduction system having been activated, i.e. when the oxygen-reduced gas
mixture /
inert gas stored in compressed form in the compressed gas storage has been
introduced into the enclosed room for the rapid or initial lowering, a
replacement of
the compressed gas storage which has then been emptied or partially emptied
with
a full compressed gas storage is then inevitable in order to ensure that the
oxygen
reduction system can also realize another rapid lowering according to a
predefined
sequence of events at a later point in time.
In many cases, however, replacing or changing the compressed gas storage can
only be realized with increased effort since the compressed gas storage of an
oxygen reduction system is often not disposed so as to be freely accessibly.
Among
6
other things, this circumstance often also leads to the ongoing costs of
operating an
oxygen reduction system being relatively high.
On the basis of this problem, the present invention is based on the task of
further
developing an oxygen reduction system of the type cited at the outset so as to
further reduce the ongoing operating costs when operating the oxygen reduction
system without compromising the effectiveness or efficiency of the oxygen
reduction
system.
Accordingly, what is in particular proposed is an oxygen reduction system
which
comprises at least one gas separation system for providing an oxygen-reduced
gas
mixture at an outlet of the gas separation system as needed and a compressed
gas
storage for storing an oxygen-reduced gas mixture or inert gas in compressed
form.
The compressed gas storage is fluidly connected or connectable to at least one
enclosed area by means of a line system in order to feed at least a portion of
the gas
mixture or respectively inert gas stored in the compressed gas storage to the
at least
one enclosed area when required. On the other hand, the outlet of the gas
separation
system is or can be fluidly connected selectively to an inlet of the
compressed gas
storage or to the at least one enclosed room in order to feed the gas mixture
provided at the outlet of the gas separation system to the compressed gas
storage
and/or the at least one enclosed area as required.
The advantages able to be achieved with the inventive solution are obvious: By
the
outlet of the gas separation system being able to be fluidly connected
selectively to
an inlet of the compressed gas storage and/or to the at least one enclosed
room in
Date Recue/Date Received 2023-04-12
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the inventive oxygen reduction system, the gas separation system is accorded a
dual function. On the one hand, the gas separation system serves to feed an
oxygen-reduced gas mixture to the spatial atmosphere of the enclosed area in
order
to lower the oxygen concentration in the spatial atmosphere of the enclosed
area (=
rapid or initial lowering) or to maintain the oxygen concentration at an
already
lowered level. On the other hand, the gas separation system serves in the
refilling
of at least one compressed gas cylinder of the compressed gas storage when
required. This becomes necessary, for example, when at least some of the
oxygen-
reduced gas mixture or inert gas stored in compressed form in the compressed
gas
storage was previously introduced into the spatial atmosphere of the enclosed
area,
for example in order to rapidly lower the oxygen concentration therein to a
specific
inerted level. Such a rapid lowering by "shooting" an oxygen-reduced gas
mixture /
inert gas into the spatial atmosphere of the enclosed room becomes necessary
in
particular when the oxygen concentration in the enclosed room needs to be
lowered
as quickly as possible in the event of a fire or for the purpose of an initial
lowering.
Due to the compressed gas storage or the at least one compressed gas cylinder
of
the compressed gas storage respectively being able to be subsequently refilled
with
an oxygen-reduced gas mixture via the gas separation system, replacing the
compressed gas storage or the at least one compressed gas cylinder of the
compressed gas storage or even refilling same by means of an external system
is no
longer necessary. The present solution is thus also particularly suitable for
enclosed
areas which are accessible only with difficulty such as those located in
remote
areas, for example.
In principle, the compressed gas storage or the compressed gas container(s) of
the
compressed gas storage respectively can now even be transported and positioned
when in an empty state, which considerably simplifies transport and
installation. The
gas separation system then fills the compressed gas storage / compressed gas
containers of the compressed gas storage with an oxygen-reduced gas mixture
for
the first time prior to the initial on-site startup.
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In order to be able to optimize the capacity of the gas separation system,
i.e. the
amount of an oxygen-reduced gas mixture able to be provided per unit of time,
and
adapt it to the corresponding use, it is advantageous for there to be a
compressor
system upstream of the gas separation system by means of which an initial gas
mixture to be fed to the gas separation system can be accordingly compressed.
Depending on the mode of operation (VPSA or PSA), the degree of the initial
gas
mixture compression is thereby 1 to 2 bar or 8 to 10 bar respectively.
However, other
compressions are of course also conceivable.
The gas separation system is in particular designed to separate off at least
some of
the oxygen contained in the initial gas mixture.
Advantageously, the gas separation system is designed so as to be selectively
operated in a VPSA operating mode or in a PSA operating mode.
As indicated above, the term "initial gas mixture" used herein is to be
generally
understood as a gas mixture which, in addition to the oxygen component, in
particular also contains nitrogen and, where appropriate, additional gases
such as
for example noble gases. A conceivable initial gas mixture is for example
normal
ambient air; i.e. a gas mixture consisting of 21% by volume oxygen, 78% by
volume
nitrogen and 1% by volume of other gases. However, it also conceivable to use
some of the spatial air contained in the enclosed area as the initial gas
mixture,
whereby fresh air is preferably also added to said spatial air content.
To be generally understood by a gas separation system operating in VPSA mode
is a
system for providing nitrogen-enriched air which functions according to the
principle
of Vacuum Pressure Swing Adsorption (VPSA). In accordance with the invention,
such a VPSA system is preferably used as the gas separation system in the
oxygen
reduction system but one able, however, to be operated in a PSA mode when
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needed. The "PSA" acronym stands for "pressure swing adsorption," normally
denoting pressure swing adsorption technology.
In order to be able to switch the operating mode of the gas separation system
from
VPSA to PSA, a further development of the present invention provides for
accordingly increasing the degree of compression of the initial gas mixture
effected
by the compressor system upstream of the gas separation system. It is in
particular
provided for the degree of compression to be increased when the amount of an
oxygen-reduced gas mixture to be provided per unit of time at the outlet of
the gas
separation system needs to be increased, particularly to a value which depends
on
the amount of the oxygen-reduced gas mixture to be provided per unit of time.
The increase in the compression of the initial gas mixture realized by the
compressor
system particularly occurs in the event of a fire; i.e. when for example a
fire
characteristic is detected in the spatial atmosphere of the enclosed area or
when the
oxygen content in the spatial atmosphere of the enclosed area is to be rapidly
reduced further compared to a previously set or maintained oxygen content for
some
other reason. On the other hand, the increase in the compression realized by
the
compressor system also occurs when, for example, the compressed gas storage or
the compressed gas cylinder of the compressed gas storage respectively needs
to be
refilled with an oxygen-reduced gas mixture.
It is generally provided for the gas separation system to comprise at least
one
nitrogen generator or a plurality of nitrogen generators connected in
parallel. The
at least one nitrogen generator is for example a nitrogen generator operated
pursuant to PSA or VPSA technology. Specifically, a nitrogen generator based
on
PSA/VPSA technology comprises at least one adsorber vessel containing adsorber
material which is designed to adsorb oxygen molecules when a gas containing
oxygen passes through the adsorber vessel.
CA 03006864 2018-05-29
Alternatively or additionally to a nitrogen generator operated pursuant to PSA
or
VPSA technology, the gas separation system can also comprise at least one
nitrogen
generator based on membrane technology. Such a nitrogen generator generally
uses
a membrane system which capitalizes on the fact of different gases diffusing
at
different rates through certain materials. It is hereby conceivable to use a
hollow
fiber membrane with a separation material applied to the outer surface of the
hollow fiber membrane through which oxygen can diffuse quite well whereas
nitrogen only exhibits a low diffusion rate with this separation material.
When air
flows through the inside of a hollow fiber membrane prepared in this way, the
oxygen contained in the air quickly diffuses outward through the hollow fiber
wall
while the nitrogen largely remains within the interior of the fiber so that a
concentration of nitrogen occurs upon passage through the hollow fiber.
In accordance with embodiments of the inventive oxygen reduction system, the
gas
separation system is designed as a mobile system removable from the oxygen
reduction system.
In accordance with embodiments of the inventive oxygen reduction system, same
further comprises a compressor system upstream of the gas separation system
for
compressing an initial gas mixture to be fed to the gas separation system. It
is
hereby conceivable for the compressor system upstream of the gas separation
system to be designed as a mobile system able to be removed from the oxygen
reduction system and/or the gas separation system when needed.
In accordance with embodiments of the inventive oxygen reduction system, a
compressor system is provided between the outlet of the gas separation system
and
the inlet of the compressed gas storage to compress as needed the oxygen-
reduced
gas mixture provided at the outlet of the gas separation system and to be fed
to the
compressed gas storage or the compressed gas cylinder(s) of the compressed gas
storage respectively. It is also conceivable in this context for the
compressor system
provided between the outlet of the gas separation system and the inlet of the
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compressed gas storage to be designed as a mobile system able to be removed
from
the oxygen reduction system and/or the gas separation system when needed.
In accordance with embodiments of the inventive oxygen reduction system, a
system of lines is provided by means of which the outlet of the gas separation
system is or can be selectively fluidly connected to an inlet of the
compressed gas
storage and/or to the at least one enclosed area. The line system can thereby
correspond at least in part to the line system via which the compressed gas
storage
is fluidly connected or connectable to the at least one enclosed area.
Alternatively
or additionally thereto, the line system via which the outlet of the gas
separation
system is or can be selectively fluidly connected to an inlet of the
compressed gas
storage and/or to the at least one enclosed area can be configured at least in
part
as a mobile system able to be removed from the oxygen reduction system and/or
the gas separation system when needed.
In accordance with embodiments of the inventive oxygen reduction system, same
further comprises a valve system having a first valve arrangement, wherein the
first
valve arrangement is designed to form and/or cut off a fluidic connection
between
the outlet of the gas separation system and the inlet of the compressed gas
storage.
In accordance with embodiments of the inventive oxygen reduction system, same
comprises a valve system having a second valve arrangement, wherein the second
valve arrangement is designed to form and/or cut off a fluidic connection
between an
outlet of the compressed gas storage and the at least one enclosed area.
In accordance with embodiments of the inventive oxygen reduction system, same
comprises a valve system having a third valve arrangement, wherein the third
valve
arrangement is designed to form and/or cut off a fluidic connection between
the
outlet of the gas separation system and the at least one enclosed area.
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The valve system of the aforementioned different embodiments of the inventive
oxygen reduction system can be configured at least in part as a mobile system
able
to be removed from the oxygen reduction system and/or the gas separation
system
when needed.
In accordance with embodiments of the inventive oxygen reduction system, the
compressed gas storage comprises at least one inlet and at least one outlet,
wherein the inlet of the compressed gas storage and the outlet of the
compressed
gas storage are connected to the interior of the compressed gas storage via a
connector piece. The connector piece can thereby be configured as a connector
piece common to the at least one inlet and the at least one outlet. For
example, the
connector piece can be configured as T-piece or Y-piece. Alternatively or
additionally thereto, the connector piece can be formed in a container valve
of the
compressed gas storage. For example, a pilot port of the container valve could
in
this case serve as the inlet of the compressed gas storage. Pilot ports are
normally
used to serially trigger the next of a compressed gas container. Their
function does
not apply in the case of parallel triggering.
In accordance with embodiments of the inventive oxygen reduction system, same
further comprises a control device for the preferably coordinated control of
controllable components of the oxygen reduction system. For example, the
control
device can be designed to control a valve system of the oxygen reduction
system
such that the outlet of the gas separation system is then preferably only
fluidly
connected to the inlet of the compressed gas storage when there is no fluidic
connection between the outlet of the compressed gas storage and the at least
one
enclosed area and/or no fluidic connection between the outlet of the gas
separation
system and the at least one enclosed area.
In accordance with embodiments of the inventive oxygen reduction system, same
further comprises a sensor unit for coordinating the providing of the oxygen-
reduced gas mixture at the outlet of the gas separation system, for
coordinating the
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feed of the oxygen-reduced gas mixture at the outlet of the gas separation
system
to the compressed gas storage, for coordinating the feed of the oxygen-reduced
gas
mixture at the outlet of the gas separation system to the at least one
enclosed area
and/or for coordinating the feed of the oxygen-reduced gas mixture or inert
gas
respectively stored in the compressed gas storage to the at least one enclosed
area.
In accordance with embodiments of the inventive oxygen reduction system, the
oxygen reduction system comprises at least one pressure sensor allocated to
the
compressed gas storage for the as-needed or continuous detecting of a
preferably
static and/or dynamic gas pressure of the oxygen-reduced gas mixture or inert
gas
stored in the compressed gas storage.
In accordance with embodiments of the inventive oxygen reduction system, same
comprises at least one pressure sensor allocated to the at least one enclosed
area
for the as-needed or continuous detecting of a preferably static gas pressure
in the
spatial atmosphere of the enclosed area.
In accordance with embodiments of the inventive oxygen reduction system, same
comprises at least one pressure sensor for detecting a preferably dynamic
and/or
static gas pressure at the inlet of the compressed gas storage, in particular
when
the gas mixture provided at the outlet of the gas separation system is fed to
the
compressed gas storage.
In accordance with embodiments of the inventive oxygen reduction system, same
comprises at least one temperature sensor allocated to the compressed gas
storage
for the as-needed or continuous detecting of a temperature of the oxygen-
reduced
gas mixture or inert gas stored in the compressed gas storage.
In accordance with embodiments of the inventive oxygen reduction system, same
comprises at least one sensor allocated to the gas separation system for the
as-
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needed or continuous detecting of a residual oxygen concentration in the
oxygen-
reduced gas mixture provided at the outlet of the gas separation system.
In accordance with embodiments of the inventive oxygen reduction system, the
at
least one gas separation system has a first operating mode, in which an oxygen-
reduced gas mixture is fed when required to the compressed gas storage or to
the
at least one compressed gas container of the compressed gas storage
respectively,
and a second operating mode, in which an oxygen-reduced gas mixture is fed
when
required to at least one enclosed area, wherein the first and second operating
mode
can preferably be set by a control device and even more preferentially
automatically, in particularly selectively automatically, by a control device.
In accordance with embodiments of the inventive oxygen reduction system, a
compressor system is arranged upstream of the at least one gas separation
system,
wherein the upstream compressor system has a first operating mode, in which an
oxygen-reduced gas mixture is fed when required to the compressed gas storage
or
to at least one compressed gas container of the compressed gas storage
respectively, and a second operating mode, in which an oxygen-reduced gas
mixture
is fed when required to at least one enclosed area, wherein the first and
second
operating mode can preferably be set by a control device and even more
preferentially automatically, in particularly selectively automatically, by a
control
device.
In accordance with embodiments of the inventive oxygen reduction system, the
outlet of the gas separation system is connected or connectable to a first
collecting
line via a valve. It is in particular provided for the first collecting line
and/or the
valve to be designed as a mobile system able to be removed from the oxygen
reduction system and/or the gas separation system as needed.
In accordance with embodiments of the inventive oxygen reduction system, the
compressed gas storage comprises a plurality of spatially separated compressed
gas
CA 03006864 2018-05-29
containers connected together in parallel having at least one, preferably one
respective container valve in each case. Hereby conceivable is for a first
line section
to be provided to preferably each of the plurality of compressed gas
containers, via
which the respective container valve of the compressed gas container is
fluidly
connected to a first collecting line. The container valve of preferably each
of the
plurality of compressed gas containers is preferably fluidly connected in each
case
to a second collecting line via a second line section. In particular
conceivable in this
context is for the second collecting line to be fluidly connected or
connectable to the
at least one enclosed area via a valve, in particular an area valve.
Preferably, the
second collecting line and/or the valve is/are designed as a mobile system
which is
able to be removed from the oxygen reduction system and/or the gas separation
system when needed.
In accordance with embodiments of the inventive oxygen reduction system, a
control device is provided which is designed to preferably automatically, and
even
more preferentially, selectively automatically actuate the valve arrangements
allocated to the oxygen reduction system in coordinated manner such that the
outlet
of the at least one gas separation system can be fluidly connected to the
inlet of at
least one compressed gas container when there is a fluidic connection between
the
outlet of at least one further compressed gas container and the at least one
enclosed area.
In accordance with embodiments of the inventive oxygen reduction system, a
control device is provided which is designed to preferably automatically, and
even
more preferentially, selectively automatically actuate the valve arrangements
allocated to the oxygen reduction system in coordinated manner so as to
selectively
establish a fluidic connection between the inlet of the least one compressed
gas
container and the outlet of the gas separation system upon the detecting of a
predetermined or determinable minimum pressure and/or upon at least one of the
compressed gas containers falling below a predetermined or determinable
minimum
pressure.
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In accordance with embodiments of the inventive oxygen reduction system, a
backflow preventer, in particular designed as a check valve, is allocated to
at least
one compressed gas container to block a flow of gas to the compressed gas
container from a line system running between the compressed gas container and
the
enclosed area.
In accordance with embodiments of the inventive oxygen reduction system, a
backflow preventer, in particular designed as a check valve, is allocated to
at least
one compressed gas container to block a flow of gas from the compressed gas
container to a line system running between the outlet of the at least one gas
separation system and the compressed gas container.
In accordance with embodiments of the inventive oxygen reduction system, at
least
one of the plurality of compressed gas containers comprises a container valve
having a preferably pneumatically actuatable quick release valve arrangement
for
the as-needed establishing of a fluidic connection between the respective
compressed gas container and a line system running between the compressed gas
container and the enclosed area. Conceivable in this context is for the valve
function
of the quick release valve arrangement to be able to switched off when
required,
particularly when the outlet of the gas separation system is or is to be
connected to
the inlet of the compressed gas container.
In accordance with embodiments of the inventive oxygen reduction system, the
gas
separation system comprises a first gas separator, for example in the form of
a
nitrogen generator, and at least one further second gas separator, for example
likewise in the form of a nitrogen generator. Hereby conceivable is for the
first gas
separator to be configured as a gas separator intended to be stationary,
whereby
the at least one second gas separator is configured as a mobile gas separator.
Alternatively conceivable thereto is for the first and the at least one second
gas
separator to each be configured as gas separators intended to be stationary.
Further
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conceivable is for the first and the at least one second gas separator to each
be
configured as mobile gas separators.
In accordance with embodiments of the inventive oxygen reduction system, a
sensor
device is provided for monitoring the residual oxygen content of the oxygen-
reduced
gas mixture provided at the outlet of the gas separation system. Thereby
conceivable is for a control device to be provided which is designed to only
feed the
oxygen-reduced gas mixture provided at the outlet of the gas separation system
to
the compressed gas storage or the at least one compressed gas container of the
compressed gas storage respectively when the residual oxygen content of the
oxygen-reduced gas mixture provided at the outlet of the gas separation system
does not exceed a predefined or definable threshold.
In accordance with embodiments of the inventive oxygen reduction system, the
nitrogen concentration of the oxygen-reduced gas mixture provided at the
outlet of
the gas separation system can be switched between at least two predefined or
definable values. Thereby conceivable is for the gas separation system to be
designed
to provide an oxygen-reduced gas mixture having a first nitrogen concentration
at the
outlet of the gas separation system when the oxygen-reduced gas mixture
provided
at the outlet of the gas separation system is to be fed to the at least one
enclosed
area and to provide an oxygen-reduced gas mixture having a second nitrogen
concentration at the outlet of the gas separation system when the oxygen-
reduced
gas mixture provided at the outlet of the gas separation system is to be fed
to the
compressed gas storage or at least one compressed gas container of the
compressed
gas storage. The first nitrogen concentration is in particular thereby lower
than the
second nitrogen concentration. For example, the second nitrogen concentration
amounts to at least 99% by volume.
According to a further aspect of the present invention, a compressor system is
provided between the outlet of the gas separation system and the inlet of the
compressed gas storage for the as-needed compressing of the oxygen-reduced gas
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mixture provided at the outlet of the gas separation system and to be fed to
the
compressed gas storage or at least one compressed gas container of the
compressed gas storage respectively. Such a compression is necessary if, for
example, the pressure of the gas mixture provided at the outlet of the gas
separation system is not sufficient to achieve the desired compression for
storing
the gas mixture in the compressed gas storage.
The compressor system which is provided as required in order to accordingly
further
compress the oxygen-reduced gas mixture provided at the outlet of the gas
separation system and to be fed to the compressed gas storage or the at least
one
compressed gas container of the compressed gas storage is preferably
configured as
a mobile system which can also be removed completely from the oxygen reduction
system when needed, and particularly when a filling of the compressed gas
storage,
or at least one compressed gas container of the compressed gas storage
respectively, is not necessary or not performed.
In this context it would for example be conceivable for the compressor system
configured as a mobile system to be mounted or mountable on a transport pallet
or
similar structure able to be moved and/or loaded by means of a floor conveyor,
e.g.
a pallet truck or forklift, so as to enable the easiest possible removal of
the
compressor from the oxygen reduction system. Since in practice the compressed
gas
storage commonly only needs to be filled occasionally, configuring the
compressor
system as a mobile system allows said compressor system to be used with
different
oxygen reduction systems, potentially also including those spatially separated
from
one another, in order to accordingly compress the oxygen-reduced gas mixture
to
be fed to a compressed gas storage to be filled at that site as needed.
It is to be emphasized here that according to one inventive concept for the
refilling
of the compressed gas storage, the oxygen-reduced gas mixture is in particular
provided by a gas separation system, whereby the compressed gas storage is in
particular a compressed gas cylinder or a battery of compressed gas cylinders.
CA 03006864 2018-05-29
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Furthermore, it is likewise possible for the compressed gas storage to exhibit
any
external shape taking into account the on-site spatial conditions and thus
allowing
an optimum use of the available space.
It is of course also conceivable and advantageous in this context for the gas
separation system as well or only the gas separation system to be configured
as a
mobile system able to be removed from the oxygen reduction system (on site)
when
needed.
As already stated in conjunction with the compressor system, the term "mobile
system" as used herein is in particular understood as a component which is
integrated into the oxygen reduction system such that this component can be
removed from the system without much effort. In particular, it is appropriate
here
for the component to be configured so as to be able to be moved by a floor
conveyor or the like.
In one preferential realization of the inventive oxygen reduction system, same
comprises a valve system having a first, a second and a third valve
arrangement.
The first valve arrangement is thereby configured so as to
establish/disconnect a
fluidic connection between the outlet of the gas separation system and the
inlet of
the compressed gas storage as required. The second valve arrangement of the
valve
system is configured so as to establish/disconnect a fluidic connection
between the
outlet of the compressed gas storage and the at least one enclosed area as
required, while the third valve arrangement is configured to establish/
disconnect a
fluidic connection between the outlet of the gas separation system and the at
least
one enclosed area as required.
Thereby preferably provided for in a manner which is particularly easy to
realize and
yet effective is the inlet of the compressed gas storage and the outlet of the
compressed gas storage being connected to the interior of the compressed gas
CA 03006864 2018-05-29
storage by a preferably common connector piece, in particular in the form of a
T-
piece or Y-piece.
The inventive oxygen reduction system preferably comprises a control device
for the
coordinated actuating of the individual valve arrangements of the valve
system. The
control device is in particular constructed to actuate the individual valve
arrangements of the valve system such that the outlet of the gas separation
system
is only fluidly connected to the inlet of the compressed gas storage, or to
the inlet
of at least one compressed gas container of the compressed gas storage
respectively, when there is no fluidic connection between the outlet of the
compressed gas storage and the at least one enclosed area and/or when there is
no
fluidic connection between the outlet of the gas separation system and the at
least
one enclosed area. Of course, setting a different priority is also conceivable
in this
context.
In some embodiments, two or even three separate control devices can also be
provided: one for establishing/disconnecting the connection between the outlet
of
the gas separation system and the compressed gas storage or at least one
compressed gas container of the compressed gas storage respectively (refill
control)
as well as one or two additional for establishing/disconnecting the connection
between the outlet of the compressed gas storage and the enclosed room
(controlling the initial or rapid lowering and full inertization) and between
the outlet
of the gas separation system and the enclosed room (controlling the base
inertization or the maintaining of an oxygen concentration in the enclosed
room
respectively).
According to a further aspect of the inventive oxygen reduction system, it is
provided for a sensor unit to be allocated to the control device. Preferably,
the
sensor unit is formed by at least one pressure sensor and/or at least one
temperature sensor. In particular provided is for the pressure sensor and/or
the
temperature sensor to be able to measure the state, in particular the fill
level or
CA 03006864 2018-05-29
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degree of filling respectively, of the compressed gas storage or at least one
compressed gas container of the compressed gas storage respectively. During
the
refilling of the compressed gas storage with oxygen-reduced gas mixture, the
temperature inside the compressed gas storage or at least one compressed gas
container of the compressed gas storage may increase, thus resulting in an
incomplete refilling of the compressed gas storage with oxygen-reduced gas
mixture
after the refilling process due to the subsequent decrease in temperature and
accompanying decrease in pressure.
The at least one pressure sensor and/or the at least one temperature sensor
provided in particular in and/or on the compressed gas storage advantageously
enables the control device to factor in temperature-dependent pressure
conditions,
e.g. when the compressed gas storage or at least one compressed gas container
of
the compressed gas storage is being preferably automatically refilled with
oxygen-
reduced gas mixture. In this regard, it is likewise conceivable for the
control device
to control the bleed of oxygen-reduced gas mixture from the compressed gas
storage upon a temperature-dependent increase in pressure in the compressed
gas
storage or at least one compressed gas container of the compressed gas storage
so
as to prevent damage to the compressed gas storage.
In one preferential form of the inventive oxygen reduction system, the at
least one
gas separation system and/or the upstream compressor system has a first
operating
mode and a second operating mode for the as-needed feeding of oxygen-reduced
gas mixture to the compressed gas storage or to at least one compressed gas
container of the compressed gas storage respectively and/or the at least one
enclosed area. It is preferably further conceivable to provide a respective
independent gas separation system for each operating mode. Thus, the first and
second modes of operation can in each case be individually or simultaneously
realized by means of independent gas separation systems. The gas separation
system or the operating mode of the at least one gas separation system and/or
upstream compressor system can thereby preferably be controlled, in particular
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automatically, by the control device. It is to be noted in this regard that
the
compressed gas storage, or the at least one compressed gas container of the
compressed gas storage respectively, is typically filled with an oxygen-
reduced gas
mixture having a higher nitrogen concentration than is required for the oxygen-
reduced gas mixture fed to the enclosed area.
In so doing, the oxygen-reduced gas mixture of higher nitrogen concentration
produced in the first operating mode of the gas separation system, preferably
at a
nitrogen concentration of 99.5% by volume, can be used to refill the
compressed
gas storage. This oxygen-reduced gas mixture produced in the first operating
mode
of the gas separation system can at the same time optionally be used for the
as-
needed supplying of oxygen-reduced gas mixture to the enclosed area, same
being
able to be diluted for this purpose to a sufficient nitrogen concentration, in
particular a nitrogen concentration of 95% by volume. Furthermore, the control
device provides the opportunity of operating the gas separation system in a
second
mode of operation, wherein oxygen-reduced gas mixture of sufficient nitrogen
concentration, preferably a nitrogen concentration of 95% by volume, is
provided
for the feed into the enclosed area.
It is thus conceivable that when refilling the compressed gas storage at a
high
nitrogen concentration, a portion of the oxygen-reduced gas mixture produced
is fed
to the enclosed area via a bypass. For example, the fluidic connection between
the
outlet of the gas separation system and the enclosed area can accordingly be
used
as a bypass in conjunction with the third valve arrangement. The bypass
thereby
preferably comprises an appropriate baffle to reduce the nitrogen
concentration of
the oxygen-reduced gas mixture to be fed to the enclosed area to an adequate
level, for example by intermixing it with an initial gas mixture. The
advantageous
control of the gas separation system, preferably automatically by the control
device,
enables efficiently operating the gas separation system and optimally using
the
oxygen-reduced gas mixture as a function of the concentration provided.
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23
Furthermore, utilizing two gas separation systems enables using one gas
separation
system in a first operating mode to refill the compressed gas storage and the
other
gas separation system in a second operating mode, particularly in parallel, to
feed
an oxygen-reduced gas mixture of an appropriately adequate nitrogen
concentration
to the enclosed area. Within the meaning of the present invention, a common or
a
respective individual upstream compressor system can thereby be provided as
needed for multiple gas separation systems.
A further aspect of the inventive oxygen reduction system provides for the
compressed gas storage to comprise a plurality of spatially separated
compressed
gas containers connected together in parallel having at least one, preferably
one
respective container valve in each case. In addition, a first as well as a
second
collecting line are provided. The outlet of the gas separation system is or
can be
thereby connected to the first collecting line via a valve, while a first line
section is
preferably provided each of the plurality of compressed gas containers via
which the
respective container valve of the one or more compressed gas containers is
fluidly
connected to the first collecting line. The container valve of preferably each
of the
plurality of compressed gas containers is furthermore fluidly connected to the
aforementioned second collecting line in each case via a second line section.
The
second collecting line itself is or can be fluidly connected to the at least
one
enclosed area via a valve, in particular an area valve.
In this embodiment, the valve via which the outlet of the gas separation
system is
or can be connected to the first collecting line forms the previously cited
first valve
arrangement. On the other hand, the valve via which the second collecting line
is or
can be fluidly connected to the at least one enclosed area is a part of the
second
valve arrangement if the oxygen reduction system is associated with multiple
enclosed areas. If the oxygen reduction system is only assigned to a single
enclosed
area, however, the valve via which the second collecting line is or can be
fluidly
connected to the at least one enclosed area forms the second valve
arrangement.
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It can furthermore be provided for a plurality of compressed gas containers in
the
form of compressed gas cylinders or of any arbitrary geometric shape to be
fluidly
connected together for example via flexible hose connections or via rigid
connections such as e.g. pipe connections, whereby one common container valve
is
provided per combination of multiple compressed gas containers into one unit.
In
particular with compressed gas containers of arbitrary external shape and
adapted
to the respectively spatial conditions, so doing gives rise to the possibility
of making
optimal use of the individually available space, whereby the number of
container
valves to be controlled can be reduced according to need.
The oxygen reduction system according to the invention is in particular suited
to
reducing, or respectively maintaining at a reduced value, the oxygen content
in the
spatial atmosphere in the case of multiple areas spatially separated from one
another. According to a further development of the present invention, the
oxygen
reduction system is therefore associated with a plurality of spatially
separated
areas, wherein the aforementioned second valve arrangement has an assigned
valve
(in particular an area valve) for each of the plurality of areas via which the
second
collecting line is or can be fluidly connected to the corresponding area in
order to
feed an oxygen-reduced gas mixture / inert gas to the area as required.
Provided in a further preferential form of the oxygen reduction system
according to
the invention is for the control device to control the individual valve
arrangements
in a coordinated manner such that the outlet of the at least one gas
separation
system can be fluidly connected to the inlet of at least one compressed gas
container when the outlet of at least one further compressed gas container is
fluidly
connected to at least one enclosed area. The control device is accordingly
designed,
in particular in conjunction with the sensor unit, to selectively fill
compressed gas
containers with an oxygen-reduced gas mixture while the at least one enclosed
area
can be fed oxygen-reduced gas mixture from further compressed gas containers.
CA 03006864 2018-05-29
This thereby advantageously ensures a resource-friendly and time-optimized
compressed gas container refilling with an oxygen-reduced gas mixture while
simultaneously being able to maintain a concentration or concentration control
range of an oxygen-reduced gas mixture in the enclosed area. Furthermore, the
reliability of the oxygen reduction system is likewise improved by the
selective
refilling and control of the compressed gas containers provided by the control
device.
In one preferential realization of the inventive oxygen reduction system, the
control
device is designed such that upon the detecting of a predefined minimum
pressure
and/or the falling below of a predefined minimum pressure in at least one of
the
plurality of compressed gas containers or compressed gas storage respectively,
a
fluidic connection is or can be selectively provided between the outlet of the
gas
separation system and the respective compressed gas container or compressed
gas
storage. The minimum pressure is freely selectable and serves to indicate the
at least
partial or complete depletion of a compressed gas container. Thus, the control
device
can determine a user-defined status or threshold level for refilling a
compressed gas
container or the compressed gas storage respectively based on a minimum
pressure
and, if applicable, initiate a corresponding refilling. As a result, a
resource-saving
compressed gas container or compressed gas storage refilling is ensured.
Furthermore, it is thereby possible to detect leakages of e.g. the compressed
gas
storage when the control device detects a minimum pressure or a drop below
said
minimum pressure respectively in at least one compressed gas container by way
of
the sensor unit and the control device preferably automatically starts a
refilling of the
compressed gas container with an oxygen-reduced gas mixture.
The invention is not solely limited to an oxygen reduction system but also
relates to
a method of operating an oxygen reduction system, in particular an oxygen
reduction system of the above-described inventive type. The method first
provides
for storing an oxygen-reduced gas mixture or inert gas in compressed form in a
compressed gas storage. To rapidly reduce the oxygen content in the spatial
CA 03006864 2018-05-29
26
atmosphere of an enclosed area, at least some of the gas mixture or inert gas
stored in compressed form in the compressed gas storage or in at least one
compressed gas container of the compressed gas storage is then fed to the
enclosed
area and that by the compressed gas storage, or at least one compressed gas
container of the compressed gas storage respectively, being fluidly connected
to the
enclosed area. In order to maintain a reduced oxygen content in the spatial
atmosphere of the enclosed area and/or to further reduce the oxygen content in
the
spatial atmosphere of the enclosed area, an oxygen-reduced gas mixture
provided
at an outlet of a gas separation system is fed to the enclosed area in
regulated
manner and that by the outlet of the gas separation system being fluidly
connected
to the enclosed area.
Particularly provided in the operating method according to the invention is an
at
least partial refilling of the compressed gas storage, or at least one
compressed gas
container of the compressed gas storage respectively, following the initial
lowering
or rapid lowering of the oxygen content in the enclosed area by means of a
feed of
the gas mixture or inert gas compressed in the compressed gas storage and that
by
the outlet of the gas separation system being fluidly connected to the
compressed
gas storage or to the at least one compressed gas container of the compressed
gas
storage.
One preferential realization of the inventive method provides for at least a
portion of
the gas mixture or inert gas stored in compressed form in the compressed gas
storage or in the at least one compressed gas container of the compressed gas
storage respectively being fed to the enclosed area during the initial
lowering or the
rapid lowering of the oxygen content in the enclosed area such that the oxygen
concentration in the enclosed area does not fall below a predefined or
definable first
value subject in particular to a fire load of the enclosed area and does not
exceed a
likewise predefined or definable second value, wherein the second value is
less than
the value of the oxygen concentration in the normal atmosphere and greater
than the
first value. It is in particular conceivable in this context for the oxygen-
reduced gas
CA 03006864 2018-05-29
27
mixture provided at the outlet of the gas separation system during the
sustained
flooding occurring subsequent to the initial lowering or rapid lowering to be
fed to
the enclosed area in regulated manner such that the oxygen concentration in
the
enclosed area does not fall below the first value as predefined or definable
in
particular as a function of the fire load of the enclosed area and does not
exceed the
predefined or definable second value.
Preferably, the first and second predefined or definable oxygen concentration
values
correspond here to lower and upper limit values of a base inerted level of the
enclosed area.
Provided according to a further aspect of the inventive method is for the
oxygen-
reduced gas mixture provided at the outlet of the gas separation system during
the
sustained flooding following the initial or rapid lowering to only be fed to
the
enclosed area in regulated manner when it has been preferably automatically
verified, in particular by means of at least one fire detector, or manually
verified, in
particular by actuating a corresponding switch, that no fire is present within
the
enclosed area during or after the initial lowering and/or rapid lowering.
Provided in one preferential realization of the inventive method is the
automatic
verifying, in particular by means of at least one fire detector, and/or manual
verifying, in particular by actuation of a corresponding switch, that a fire
having
broken out in the enclosed room has not been or not sufficiently suppressed
subsequent the initial lowering or rapid lowering. It is thereby in particular
provided that after verification that a fire which broke out in the enclosed
room
has not been or not sufficiently suppressed, the oxygen content in the spatial
atmosphere of the enclosed area is further reduced and that done by feeding at
least a portion of the gas mixture or inert gas stored in compressed form in
the
compressed gas storage or in at least one compressed gas container of the
compressed gas storage to the enclosed area, and by fluidly connecting the
CA 03006864 2018-05-29
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compressed gas storage or at least one compressed gas container of the
compressed gas storage to the enclosed area.
In particular conceivable in this context is that after verifying that a fire
which had
broken out in the enclosed room has not been or not sufficiently suppressed,
the
oxygen content in the spatial atmosphere of the enclosed area is continued to
be
reduced until the oxygen concentration in the enclosed area reaches a
predefined or
definable target concentration which corresponds to a nitrogen concentration
at
least as equally high as an extinguishing gas concentration dependent on the
fire
load of the enclosed area. The predefined or definable target oxygen
concentration
in the enclosed area thereby preferentially corresponds to a fully inerted
level.
Alternatively or additionally conceivable in this context is maintaining the
predefined
or definable target oxygen concentration in the enclosed area (sustained
flooding)
subsequent the further reduction of the oxygen content in the spatial
atmosphere of
the enclosed area, and doing so by feeding an oxygen-reduced gas mixture
provided
at the outlet of the gas separation system to the enclosed area in regulated
manner,
and by the outlet of the gas separation system being fluidly connected to the
enclosed area. During said sustained flooding, at least a partial refilling of
the
compressed gas storage or respectively at least one compressed gas container
of
the compressed gas storage preferentially occurs, and that by the inlet of the
gas
separation system being fluidly connected to the compressed gas storage or the
at
least one compressed gas container of the compressed gas storage respectively.
Provided according to a further aspect of the inventive method is for the
enclosed
area to be preferably continuously monitored or monitored at predefined or
predefinable times/events with regard to the presence of at least one fire
characteristic. Conceivable in this context is for at least the initial or
respectively
rapid lowering to be preferably automatically initiated as soon as at least
one fire
characteristic is detected.
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29
According to a further aspect of the present invention, a control device is
provided
which is in particular designed to monitor the filling of the compressed gas
storage
or the at least one compressed gas container of the compressed gas storage
respectively in coordinating or regulating manner. The at least partial
refilling of the
compressed gas storage / at least one compressed gas container of the
compressed
gas storage can in particular also take place simultaneously to the reduced
oxygen
content in the enclosed area being maintained and/or the oxygen content in the
enclosed area being further reduced. This aspect of the invention is thereby
based
on the realization that different conditions must be met when filling the
compressed
gas storage, particularly when it is in the form of a battery of compressed
gas
cylinders, in order to properly and safely fill the individual compressed gas
cylinders
of the battery of cylinders with the gas provided by the gas separation
system.
Cited as just one example in this context is that there are different cylinder
filling
pressures for compressed gas cylinders. If a compressed gas cylinder is filled
at the
wrong pressure, the cylinder will not fill completely or an excess pressure
will be
generated which can damage the compressed gas cylinder (e.g. an excess
pressure
lid of the cylinder can then break).
The following will reference the accompanying drawings in describing example
embodiments of the inventive oxygen reduction system in greater detail.
Shown are:
Fig. 1 a schematic view of a first example embodiment of the oxygen
reduction
system according to the invention;
Fig. 2 a schematic view of a second example embodiment of the oxygen
reduction system according to the invention;
CA 03006864 2018-05-29
Fig. 3 a schematic view of a container valve arrangement by means of which
the respective compressed gas container is or can be connected to the
first and second collecting line of the oxygen reduction system in the
example embodiments;
Fig. 4 a schematic view of a third example embodiment of the oxygen
reduction
system according to the invention;
Fig. 5a a schematic block diagram to illustrate different example connections
of a control device of one example embodiment of the inventive
oxygen reduction system to components of the oxygen reduction
system;
Fig. 5b another schematic block diagram to illustrate different example
connections of a control device of one example embodiment of the
inventive oxygen reduction system to grouped components of the
oxygen reduction system; and
Fig. 6 a schematic flow chart of an example control sequence for
controlling or
respectively operating an oxygen reduction system according to one
example embodiment of the invention.
The present invention is based on the problem of after a conventional oxygen
reduction system having been activated; i.e. when the oxygen-reduced gas
mixture
or inert gas stored in compressed form in a compressed gas storage has been
piped
into an enclosed room for a rapid or initial lowering, the emptied compressed
gas
storage then usually has to be replaced. In many cases, however, replacing the
compressed gas storage can only be realized at increased effort since the
compressed gas storage of an oxygen reduction system is often not freely
accessible. Among other things, this circumstance also leads to the ongoing
operating costs of an oxygen reduction system often being relatively high.
CA 03006864 2018-05-29
31
Additionally, if no reserve compressed gas storage is provided, fire
protection
cannot be ensured or not fully ensured while the compressed gas storage is
being
replaced.
In view of these problems, it is the task of the present invention to specify
an
oxygen reduction system in which its ongoing operating costs can be reduced
without the effectiveness of the oxygen reduction system being compromised.
Accordingly proposed is an oxygen reduction system comprising at least one gas
separation system for the as-needed providing of an oxygen-reduced gas mixture
at
an outlet of the gas separation system and one compressed gas storage, in
particular in the form of one or more compressed gas containers, for storing
an
oxygen-reduced gas mixture or inert gas in compressed form. The compressed gas
storage is fluidly connected or connectable via a line system to at least one
enclosed
area for the as-needed feeding of at least a portion of the gas mixture/ inert
gas
stored in the compressed gas storage to the at least one enclosed area. It is
thereby provided for the outlet of the gas separation system to be fluidly
connected
or connectable selectively and/or when needed to an inlet of the compressed
gas
storage and/or to the at least one enclosed area for the as-needed feed of the
gas
mixture provided at the outlet of the gas separation system to the compressed
gas
storage and/or to the at least one enclosed area.
In accordance with implementations of the oxygen reduction system, at least
one
control device is provided in order to at least partly automatically and in
particular
selectively automatically establish the fluidic connection between the outlet
of the
gas separation system and the inlet of the compressed gas storage and/or the
at
least one enclosed area.
The at least one control device is preferably a combined hardware/software
mechanism. Input signals such as sensor measurements or user configuration
inputs
can be processed by the at least one control device and calculated by means of
a
CA 03006864 2018-05-29
32
control software, e.g. WAGNER OxyControl . The control device can comprise a
programmable logic control (PLC) such as available from Siemens AG, Munich, as
the S7 or from WAGO Kontakttechnik GmbH, Minden, as type 750.
In accordance with embodiments of the inventive oxygen reduction system, the
at
least one control device is configured to receive sensor data, to provide
information, e.g. by displaying or dispensing status or detector data, to
actuate a
compressor/compressor system and the gas separation system, and to actuate the
valve arrangements associated with the oxygen reduction system.
In one embodiment, the valve arrangements comprise both electromagnetic
control
valves as well as pneumatic area valves. The control device is thereby
configured to
generate and to emit electrical actuation signals in order to actuate the
electromagnetic control valves. The control valves are fluidly connected or
connectable to a control gas source, e.g. a pilot gas cylinder or control gas
cylinder.
As soon as the control valves are actuated, control gas flows out of the pilot
gas
cylinder or control gas cylinder and actuates the pneumatic area valves as
required.
In a further embodiment, an additional fire alarm control panel is provided as
a
secondary control device. The fire alarm control panel is configured so as to
receive
fire detection data from corresponding fire detectors, process fire alarm data
and
signal a fire alarm. One example fire alarm control panel can be obtained from
Labor Strauss Sicherungsanlagenbau GmbH, Vienna, Austria. Both the control
device
as well as the fire alarm control panel can be configured so as to be
activated in the
event of potentially dangerous conditions, e.g. smoke, fire or critical oxygen
concentrations.
According to a further aspect of the oxygen reduction system, a sensor unit is
allocated to the control device. The sensor unit preferably comprises at least
one
pressure sensor and/or at least one temperature sensor. In particular, the
pressure
sensor and/or the temperature sensor measure(s) the state of the compressed
gas
CA 03006864 2018-05-29
33
storage, in particular its fill level or respectively degree of filling.
During the refilling
of the compressed gas storage with an oxygen-reduced gas mixture, the
temperature in the compressed gas storage can increase, which leads to an
incomplete refilling of the compressed gas storage and thus also to a
subsequent
drop in pressure.
Preferentially, temperature-dependent pressure conditions in the compressed
gas
storage can be detected by means of the at least one pressure sensor and/or
the at
least one temperature sensor, as in particular provided in and/or on the
compressed
gas storage, and communicated to the control device so that the refilling of
the
compressed gas storage with oxygen-reduced gas mixture ensues subject to the
temperature-dependent pressure conditions. In this regard, it is also
conceivable for
the control device to control or respectively regulate the release of oxygen-
reduced
gas mixture from the compressed gas storage in response to a temperature-
dependent increase in pressure and thus prevent damage to the compressed gas
storage.
In one embodiment of the oxygen reduction system, the at least one gas
separation
system and/or a compressor system arranged upstream of the gas separation
system has a first operating mode and a second operating mode for feeding the
oxygen-reduced gas mixture to the compressed gas storage and/or to the at
least
one enclosed area. Preferably, each operating mode is associated with an
independent gas separation system. By so doing, the first and the second
operating
mode are individually or simultaneously operable by independent gas separation
systems. To this end, the gas separation system or the operational mode of the
at
least one gas separation system and/or a compressor system arranged upstream
of
the gas separation system is preferably, in particular automatically,
controlled by
the control device. To be noted in this regard is that the refilling of the
compressed
gas storage with an oxygen-reduced gas mixture is typically effected at a
higher
nitrogen concentration than is required for the feed to the enclosed area.
CA 03006864 2018-05-29
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In this way, the oxygen-reduced gas mixture produced in a first gas separation
system operating mode of higher nitrogen concentration, preferably at a
nitrogen
concentration of 99.5% by volume, can be used when needed to refill the
compressed gas storage. The gas mixture produced in a first gas separation
system
operating mode can optionally also be used simultaneously to provide an oxygen-
reduced gas mixture to the enclosed area, whereby the oxygen-reduced gas
mixture
is then diluted to a nitrogen concentration of e.g. 95% by volume.
The control device provides the further opportunity of operating the gas
separation system in a second mode of operation in which an oxygen-reduced gas
mixture having an effective nitrogen concentration, preferably a nitrogen
concentration of 95% by volume, is provided which can then be fed to the
enclosed area.
It is thus for example conceivable that when refilling the compressed gas
storage at
a high nitrogen concentration, a portion of the oxygen-reduced gas mixture
generated is fed to the enclosed area via a bypass. For example, the fluidic
connection between the outlet of the gas separation system and the enclosed
area
can be used as a bypass in conjunction with the third valve arrangement. For
this
purpose, the bypass preferably comprises an applicable baffle for reducing the
nitrogen concentration of the oxygen-reduced gas mixture to be fed to the
enclosed
area to an effectual level or e.g. a mixing chamber in which the oxygen-
reduced gas
mixture is mixed with an initial gas mixture. Advantageously controlling the
gas
separation system, preferably automatically by the control device, enables the
gas
separation system to be operated efficiently and the optimal use of the oxygen-
reduced gas mixture pursuant to the concentration as provided.
Furthermore, using two gas separation systems enables one gas separation
system
to be operated in a first mode of operation to refill the compressed gas
storage and
the other gas separation system to preferably be operated in parallel in a
second
mode of operation in order to provide the enclosed area with an oxygen-reduced
CA 03006864 2018-05-29
gas mixture at an effectual nitrogen concentration. It is conceivable for a
common
or an individual upstream compressor system to be provided for each of the gas
separation systems.
According to a further aspect of the oxygen reduction system, a system is
provided in
which the compressed gas storage comprises a plurality of compressed gas
containers
connected parallel to one another and preferably each having at least one
container
valve. In addition, a first and a second collecting line are provided.
The outlet of the gas separation system is thus connected or connectable to
the first
collecting line via a valve, while a first line section is provided for
preferably each of
the plurality of compressed gas containers via which the respective container
valve
is fluidly connected to the first collecting line. The respective container
valve of
preferably each of the plurality of compressed gas containers is furthermore
connected to the aforementioned second collecting line via a second line
section.
The second line section itself is fluidly connected or connectable to the at
least one
enclosed area via a valve, in particular an area valve.
In this embodiment, the valve via which the outlet of the gas separation
system is
or can be connected to the first collecting line forms the previously
mentioned first
valve arrangement. On the other hand, the valve via which the second
collecting
line is fluidly connected or connectable to the at least one enclosed area is
a part of
the second valve arrangement if the oxygen reduction system is associated with
several enclosed areas. If, however, the oxygen reduction system is only
assigned
to a single enclosed area, the valve via which the second collecting line is
fluidly
connected or connectable to the at least one enclosed area forms the second
valve
arrangement.
Example embodiments of the invention will be described in the following
referencing
the accompanying drawings.
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36
The first example embodiment of the inventive oxygen reduction system 100
depicted in Fig. 1 is characterized in particular by comprising a gas
separation
system 102 and a compressed gas storage 105 additionally thereto. The gas
separation system 102 and the compressed gas storage 105 together form the
"inert
gas source" of the oxygen reduction system 100.
A compressor system 101 is provided upstream of the gas separation system 102
in
order to accordingly compress the initial gas mixture to be fed to the gas
separation
system 102. By appropriately varying the pressure and volumetric flow of the
initial
gas mixture fed to the gas separation system 102, the gas separation system
102
can be adjusted to a stipulated nitrogen concentration and required volume of
oxygen-reduced gas.
To be emphasized at this point, however, is that it is not necessarily
imperative for
a corresponding compressor system 101 to be connected upstream of the gas
separation system 102.
The outlet of the gas separation system 102; i.e. the exit of the gas
separation
system 102, at which the oxygen-reduced gas mixture or nitrogen-enriched gas
mixture respectively is provided, is fluidly connected or connectable to an
enclosed
room 107 by means of a first line system and connected or connectable to the
aforementioned compressed gas storage 105 by means of an additional second
line
system. To that end, a first valve arrangement 104 is provided in the second
line
system; i.e. in the line system which connects the outlet of the gas
separation
system 102 to the compressed gas storage 105. A further valve arrangement 109
is
provided in the line system which fluidly connects the outlet of the gas
separation
system 102 to the enclosed room 107. Yet another valve arrangement 106 is
arranged in one line system which connects the compressed gas storage 105 to
the
enclosed area 107. So doing enables the compressed gas storage 105 to be
fluidly
connected to the enclosed area 107 when needed.
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37
A control device 10 is preferably allocated to the oxygen reduction system 100
according to the invention in order to be able to control the individual valve
arrangements 104, 106 and 109 in coordinated manner. The control device 10 is
thereby further allocated a sensor unit having at least one pressure sensor
and/or at
least one temperature sensor which is/are in particular provided in and/or on
the
compressed gas storage. For the sake of clarity, the sensor unit is not
depicted in
Figs. 1 to 4.
Specifically, the depicted example embodiment provides for the control device
10 to
be designed to control the individual valve arrangements 104, 106 and 109 such
that the outlet of the gas separation system 102 is then preferably only
fluidly
connected or connectable to the inlet of the compressed gas storage 105 when
there is no fluidic connection between the outlet of the compressed gas
storage 105
and the at least one enclosed area 107; i.e. when the third valve arrangement
106
is closed. Moreover, the control device 10 is designed such that the outlet of
the gas
separation system 102 is then only fluidly connected or connectable to the
compressed gas storage 105 via the first valve arrangement 104 when there is
no
fluidic connection between the outlet of the gas separation system 102 and the
enclosed area 107; i.e. when the second valve arrangement 109 is closed.
It is alternatively also possible to provide the inventive oxygen reduction
system
100, in particular the control device 10, such that the outlet of the gas
separation
system 102 can when needed be fluidly connected simultaneously to the inlet of
the
compressed gas storage 105 via the first valve arrangement 104 and to the
enclosed
area 107 via the second valve arrangement 109.
In the example embodiment of the inventive oxygen reduction system 100
depicted
schematically in Fig. 1, a further compressor system 103 is provided which is
arranged in the line system connecting the outlet of the gas separation system
102
to the compressed gas container 105. This further compressor system 103
enables
the oxygen-reduced gas mixture provided at the outlet of the gas separation
system
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38
102 to be compressed further as needed so it can then be stored in compressed
gas
container 105 in the desired compressed form. If a compressed gas cylinder or
a
battery of cylinders is used as the compressed gas container, it is
advantageous for
the further compressor system 103 to compress the oxygen-reduced gas mixture
provided at the outlet of the gas separation system 102 up to 300 bar.
The oxygen reduction system 100 depicted schematically in Fig. 2 differs from
the
schematically depicted embodiment in Fig. 1 particularly in that the oxygen
reduction system 100 according to the embodiment depicted in Fig. 2 is not
allocated to only one single enclosed area 107, but rather to a plurality of
enclosed
areas 107a, 107b. The oxygen reduction system 100 is thus realized as a so-
called
multi-zone system.
A further difference to the embodiment depicted in Fig. 1 is that the
compressed
gas storage 105 of the oxygen reduction system 100 depicted schematically in
Fig. 2
comprises a plurality of spatially separated compressed gas containers 105a,
105b,
105c, 105d connected in parallel. These compressed gas containers are e.g.
commercially available high pressure cylinders (300 bar cylinders).
The individual compressed gas containers 105a to 105d are connected in
parallel to
each other so as to be able to supply the gas mixture stored in compressed
form in
these compressed gas containers 105a to 105d to the enclosed area(s) 107a,
107b
as rapidly as possible when needed.
A first collecting line 110 as well as a second collecting line 111 is used
for the
parallel connection of the compressed gas containers 105a to 105d in the
embodiment depicted schematically in Fig. 2. The first collecting line 110 can
be
fluidly connected to the outlet of the gas separation system 102 via the first
valve
arrangement 104.
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As also in the embodiment depicted schematically in Fig. 1, the oxygen
reduction
system 100 shown in Fig. 2 employs a further valve arrangement to connect the
outlet of the gas separation system 102 to the first enclosed area 107a and/or
the
second enclosed area 107b as needed. In contrast to the embodiment depicted
schematically in Fig. 1, however, this valve arrangement comprises a total of
two
valves 109a and 109b, each designed as an area valve and allocated to one of
the
respective enclosed areas 107a, 107b.
The aforementioned second collecting line 111 is likewise fluidly connectable
to the
respective enclosed areas 107a, 107b via corresponding area valves 106a, 106b.
These valves 106a, 106b are likewise preferably designed as area valves.
The following will reference the schematic representation in Fig. 3 in also
describing
the parallel connection of the individual compressed gas containers 105a to
105d in
greater detail.
Specifically, provided in the embodiment depicted schematically in the
drawings is
for each compressed gas container 105a to 105d to be provided with a
corresponding container valve 108 (see Fig. 3). Each container valve 108 of
the
compressed gas container 105a to 105d is fluidly connected to the first
collecting
line 110 on one side via a first line section and to the second collecting
line 111 on
the other side via a second line section.
A connector piece 113, in particular in the form of a T-piece or Y-piece, is
allocated
to each container valve 108 of compressed gas containers 105a to 105d for that
purpose, via which the respective first line section on the one side and the
respective second line section on the other side is fluidly connected to the
respective container valve 108 or the interior of the compressed gas container
105a
to 105d respectively.
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Preferentially, the container valves 108 of compressed gas containers 105a to
105d
are in each case implemented as a quick-release valve assembly, in particular
as a
pneumatically actuatable quick-release valve assembly, in order to establish a
fluidic
connection between the respective compressed gas containers 105a to 105d and
the
second collecting line as needed. It is thereby of advantage for the valve
function of
the quick-release valve assembly to also be able to be disabled when required,
and
that in particular when the outlet of the gas separation system 102 is or is
to be
connected to the inlet of the respective compressed gas containers 105a to
105d for
the purpose of refilling.
As schematically indicated in Fig. 3, it is further conceivable for at least
one
backflow preventer 112 to be provided between the container valve 108 of the
respective compressed gas container 105a to 105d and the first and/or second
collecting line 111, and in particular the first and/or second line section,
in order to
block a flow of gas from the second collecting line 111 back into the
compressed
gas containers 105a to 105d and/or from the compressed gas containers 105a to
105d to the first collecting line 110. According to Fig. 3, the two backflow
preventers 112 can be directly provided on a connector piece 113, in
particular a T-
piece, and fluidly connected to the container valve 108 of the respective
compressed
gas container 105a to 105d. The inlet of the compressed gas storage and the
outlet
of the compressed gas storage are then connected to the interior of the
compressed
gas storage by a preferably common connector piece 113. So doing basically
ensures that no return flow from the second collecting line 111 into one of
the
compressed gas containers 105a to 105d will occur when the quick-release valve
assembly is activated, for example when one of the compressed gas containers
105a
to 105d is at lower pressure compared to the other compressed gas container.
The embodiment depicted schematically in Fig. 4 differs from the embodiment in
Fig. 2 particularly by the further compressed gas containers 105e to 105f
which are
able to be fluidly connected to the outlet of the gas separation system by a
further
valve of the first valve arrangement 104. The control device pursuant to the
present
CA 03006864 2018-05-29
41
invention is to thereby be designed to accordingly control multiple valves of
the first
valve arrangement 104.
Just as for the compressed gas containers 105a to 105d in Fig. 2, the further
compressed gas containers 105e to 105f shown in Fig. 4 are provided with a
further first collecting line 110 and a further second collecting line 111.
Each of
the further compressed gas containers 105e to 105f are also assigned a
container
valve 108 with a connector piece 113, particularly in the form of a T-piece or
a
Y-piece, via which the respective first line section on the one side and the
respective second line section on the other side is fluidly connectable to the
respective container valve 108 or to the interior of the further compressed
gas
container 105e to 105f respectively.
The further second collecting line 111 is likewise fluidly connectable to the
respective enclosed areas via corresponding area valves 106c, 106d. These
valves
106c, 106d are preferably likewise designed as area valves.
On the basis of the embodiment of the present invention schematically depicted
in
Fig. 4, it is advantageously possible to implement the further compressed gas
containers 105e to 105g and compressed gas containers 105a to 105d as being
controlled or regulated by the control device 10 preferably independently of
each
other. In particular, e.g. the further compressed gas containers 105e to 105g
can be
refilled subsequent a rapid and/or initial lowering while, at the same time,
the
compressed gas storages 105a to 105d are connected to the enclosed areas 107a,
107b in order to maintain or further lower a reduced oxygen content in the
enclosed
areas 107a, 107b.
Of course, the compressed gas containers 105a to 105d can also be refilled
with
oxygen-reduced gas mixture from the gas separation system 102 while the
further
compressed gas containers 105e to 105g are fluidly connected to the enclosed
areas
107a, 107b. Moreover, the use of further compressed gas containers 105e to
105g is
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42
not limited to the number of compressed gas containers as depicted in Fig. 4
but
rather can be for example supplemented by further compressed gas containers or
further independently controllable assemblages of multiple compressed gas
containers respectively.
The embodiment shown in Fig. 4 advantageously enables multi-stage
inertization. In
multi-stage inertization, the compressed gas containers 105a to 105d first
lower the
oxygen concentration to a base inerted level in the event of a fire and this
level is
maintained for example by an oxygen-reduced gas mixture produced by the gas
separation system 102 being introduced into the enclosed area 107. After a
predefinable or defined interval of time, a recheck is made as to whether a
fire is
still present, for example by means of fire detectors or visual verification.
If there
is no longer any fire, the base inerted level is maintained for a further
definable or
defined interval of time so as to prevent a re-ignition. If, however, fire is
still
present, the oxygen concentration is lowered to a fully inerted level by means
of the
further compressed gas containers 105e to 105g and maintained at that level by
means of the gas separation system 102.
In particular provided is for the compressed gas storage 105, or the at least
one
compressed gas container 105a-g of the compressed gas storage 105
respectively, to
be at least partially refilled subsequent the initial lowering or a rapid
lowering of the
oxygen content within the enclosed area 107a, 107b by the introducing of the
compressed gas mixture or inert gas into the at least one compressed gas
storage
105 or the at least one compressed gas container 105a-g of the compressed gas
storage 105, and that by fluidly connecting the outlet of the gas separation
system
102 to the compressed gas storage 105 or the at least one compressed gas
container
105a-g of the compressed gas storage 105 respectively.
One preferential realization provides for at least a portion of the gas
mixture or
inert gas stored in compressed form in the compressed gas storage 105 or the
at
least one compressed gas container 105a-g of the compressed gas storage 105 to
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43
be fed to the enclosed area 107a, 107b during the initial lowering or the
rapid
lowering of the oxygen content in the enclosed area 107a, 107b such that the
oxygen concentration in the enclosed area 107a, 107b does not fall below a
predefined or definable first value which is in particular dependent on the
fire load
of the enclosed area 107a, 107b nor exceed a likewise predefined or definable
second value, wherein the second value is less than the oxygen concentration
value
of the normal atmosphere and greater than the first value. Particularly
conceivable
in this context is for the oxygen-reduced gas mixture provided at the outlet
of the
gas separation system 102 during the sustained flooding subsequent the initial
or
rapid lowering to be fed to the enclosed area 107a, 107b in such a manner that
the
oxygen concentration in the enclosed area 107a, 107b does not fall below the
predefined or definable first value particularly dependent on the fire load of
the
enclosed area 107a, 107b and does not exceed the likewise predefined or
definable
second value.
Preferably, the first and second predefined or definable oxygen concentration
values
correspond here to lower and upper limit values of a base inerted level of the
enclosed area.
Provided according to a further aspect is for the oxygen-reduced gas mixture
provided at the outlet of the gas separation system 102 during the sustained
flooding subsequent the initial lowering or rapid lowering to then only be fed
in
regulated manner to the enclosed area 107a, 107b if it has been verified
during or
after the initial lowering / rapid lowering, preferably automatically, in
particular by
means of at least one fire detector 118, and/or manually, in particular by
actuating
a corresponding switch, that no fire is present in the enclosed area 107a,
107b.
One preferential realization provides for automatically verifying, in
particular by
means of at least one fire detector 118, and/or manually verifying, in
particular by
actuating a corresponding switch, that a fire having broken out in the
enclosed room
107a, 107b has not been or not sufficiently suppressed subsequent the initial
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lowering / rapid lowering. Hereby in particular provided is for the further
reducing
of the oxygen content in the spatial atmosphere of the enclosed area 107a,
107b
following verification that a fire which broke out in the enclosed area 107a,
107b
has not been or not sufficiently suppressed, and that by at least a portion of
the gas
mixture or inert gas stored in compressed form in the compressed gas storage
105,
or respectively at least a portion of the gas mixture or inert gas stored in
compressed form in at least one compressed gas container 105a-g of the
compressed gas storage 105 being fed to the enclosed area 107a, 107b, and
namely
by fluidly connecting the compressed gas storage 105, or the at least one
compressed gas container 105a-g of the compressed gas storage 105 respectively
to
the enclosed area 107a, 107b.
Particular conceivable in this context is for the further reducing of the
oxygen
concentration in the spatial atmosphere of the enclosed area 107a, 107b,
following
verification of a fire having broken out in the enclosed area 107a, 107b not
having
been or not sufficiently suppressed, to continue until the oxygen
concentration in
the enclosed area reaches a predefined or definable target concentration
corresponding to a nitrogen concentration which is at least equally as high as
an
extinguishing gas concentration dependent on the fire load of the enclosed
room
107a, 107b. The predefined or definable oxygen target concentration in the
enclosed area 107a, 107b thereby preferentially corresponds to a fully inerted
level.
Alternatively or additionally conceivable in this context is for the
predefined or
definable oxygen target concentration in the enclosed area 107a, 107b to be
maintained (sustained flooding) subsequent the further reducing of the oxygen
content in the spatial atmosphere of the enclosed area 107a, 107b, and that by
feeding an oxygen-reduced gas mixture provided at the outlet of the gas
separation
system 102 in regulated manner to the enclosed area 107a, 107b, and namely by
fluidly connecting the outlet of the gas separation system 102 to the enclosed
area.
At least a partial refilling of the compressed gas storage 105 or a refilling
of at least
one compressed gas container 105a-g of the compressed gas storage 105 thereby
CA 03006864 2018-05-29
preferentially occurs during said sustained flooding, and that by the outlet
of the
gas separation system 102 being fluidly connected to the compressed gas
storage
105 or to at least one compressed gas container 105a-g of the compressed gas
storage 105 respectively.
Provided according to a further aspect of the inventive method is for the
enclosed
area 107a, 107b to be preferably continuously monitored or monitored at
predefined
or predefinable times or events with regard to the presence of at least one
fire
characteristic. Conceivable in this context is for at least the initial or
respectively
rapid lowering to be preferably automatically initiated as soon as at least
one fire
characteristic is detected.
Fig. 5a shows a schematic block diagram illustrating different example
connections of
a control device 10 to components of the oxygen reduction system 100 according
to
one example embodiment. The control device 10 receives inputs via different
sensors.
The sensor unit identified by the reference numeral "114" furnishes the
control device
10 with data from a temperature sensor 115 and a pressure sensor 116 located
within, at or on a compressed gas container 105. By calculating the
temperature and
pressure data, the control device 10 can effect a more precise refilling in
response to
a temperature-dependent increase in pressure in the compressed gas container
105.
Moreover, the pressure sensor 116 enables the control device 10 to detect a
drop in
pressure in the compressed gas container 105, which can be a trigger condition
for
starting the refilling.
The oxygen sensor 117 furnishes the control device 10 with values from an
oxygen
concentration measurement in the enclosed area 107a, 107b, whereby control of
the
activation or deactivation of the gas separation system 102 and/or the
upstream
compressor system 101 is possible as a function of the current oxygen
concentration.
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An optional fire alarm control panel 121 can also be connected to the control
device
in order to trigger a fire alarm mode of the control device 10, whereby the
fire
alarm mode includes for example the triggering of the oxygen reduction
system's
extinguishing mode. The extinguishing mode comprises lowering the oxygen
concentration in the enclosed area 107a, 107b to a base or fully inerted
level. A fire
detector 118, which in this case is an aspirating smoke detector, is
configured to
furnish alarm information to the fire alarm control panel 121 when smoke or
fire is
detected in an enclosed area 107a, 107b in order to enable the earliest
possible
detection of smoke in the enclosed area 107a, 107b. In the case of potentially
dangerous conditions, e.g. smoke, fire or critical oxygen concentrations, the
control
device 10 and the fire alarm control panel 121 are configured to trigger the
alarm
means 119.
It is possible to display the available information in the control device 10
via a user
interface 120, e.g. status or alarm information, and for the control device 10
to
execute intended user inputs, for example configuration inputs. The control
device
10 is moreover connected to an upstream compressor system 101 in order to
activate or deactivate said compressor system 101 or to increase or lower the
compression level of the compressor system 101.
The control device 10 is further connected to a downstream compressor system
103 in order to activate said compressor system 103 for the refilling of the
compressed gas container 105 and to deactivate it when the refilling is
finished. In
order to enable the control device 10 to be able to control the base inerted
mode,
the rapid oxygen concentration lowering mode (for fully inerting) and the
refilling
mode, the control device 10 is connected to valves 104, 106 and 109 and can
change the open or close position of said valves 104, 106 and 109.
Fig. 5b shows the components of Fig. 5a in a grouped overview as well as the
communication directions between the control device 10 and the other connected
components.
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The control device 10 exchanges signals with the sensor unit 114 which in this
example embodiment comprises at least one temperature sensor 115 for measuring
and/or monitoring the temperature of the compressed gas storage 105, at least
one
pressure sensor 116 for measuring and/or monitoring the pressure of the
compressed gas storage 105, at least one oxygen sensor 117 for measuring
and/or
monitoring the oxygen concentration in the atmosphere of the enclosed area
107a,
107b as well as at least one oxygen sensor 122 for measuring and/or monitoring
the
residual oxygen concentration at the outlet of the gas separation system 102.
The control device 10 additionally exchanges signals with the fire alarm
control
panel 121, which in turn communicates with at least one fire detector 118, in
order
to signal a fire as detected by a fire detector 118, e.g. to a primary control
unit or
the control device 10 of the oxygen reduction system. The fire alarm control
panel
121 additionally controls alarm means 119a in order to draw the attention of
people
to the fire. The alarm means 19a can for example be flashing lights,
illumination
panels and/or signal horns.
The control device 10 can likewise control its own or respectively additional
alarm
means 119b when, for example, the oxygen concentration within the enclosed
area
107a, 107b as measured by the at least one oxygen sensor 117 exceeds or falls
short of an inadmissibly high or inadmissibly low concentration.
The control device 10 additionally exchanges signals with the user interface
120,
shown as an example in the present figure as a touch panel mounted on the
control device 10. The user interface 120 displays for example configuration,
status and alarm data to the user and enables, for example, the setting up or
customizing of the control functions of the control device 10 via user inputs.
For
instance, threshold values for the sensors of the sensor device 114 can be
specified or changed via the user interface 120, whereby falling short of or
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exceeding the thresholds can lead to a signaling or to the activating of alarm
means 119b.
The control device 10 additionally exchanges signals with the gas separation
system
102, for example switching it on or off or querying the status of the gas
separation
system 102. The compressor systems 101, 103 arranged upstream and downstream
of the gas separation system 102 are also activated via the control device 10,
e.g.
their switching on and off or stepped or stepless increasing or decreasing of
the
compression level.
Moreover, the control device 10 controls the valves of the first, second and
third
valve arrangements 104, 106 and 109, e.g. the opening or closing of the
valves, in
order to selectively establish or disconnect fluidic connections between the
gas
separation system 102, the compressed gas storage 105 and the enclosed area
107a, 107b.
Fig. 6 shows a flow chart of an example control sequence for controlling an
oxygen
reduction system as shown for example in Fig. 1.
The left branch of Fig. 6 shows a sequence for the initial lowering and/or
maintaining of an oxygen-reduced concentration in the enclosed areas 107a,
107b
("base inerted" mode). The right branch of Fig. 6 shows a sequence for fire
detection, fire extinguishing ("fully inerted" mode) and refilling of the
compressed
gas containers 105a to 105d.
Both sequences are shown for the example of enclosed area 107a. Such sequences
are of course also conceivable for enclosed area 107b. Both sequences as shown
in
the left and right branch of Fig. 6 can occur individually or in parallel.
The following description refers to the left branch in Fig. 6 ("base inerted"
mode):
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The oxygen concentration within the enclosed area 107a, 107b is continuously
measured during the operation of the oxygen reduction system and the
measurement
data is furnished to the control device 10. Upon a preset maximum oxygen
concentration being reached, the control device 10 opens valve 109a and starts
the
upstream compressor system 101; i.e. upstream of the gas separation system
102, as
well as gas separation system 102 in order to feed an oxygen-reduced gas
mixture to
the enclosed area 107a. As soon as a preset minimum concentration of oxygen is
reached, the control device 10 stops the upstream compressor system 101 and
the
gas separation system 102 and closes valve 109a.
Since the oxygen concentration rises naturally due to leaks in the enclosed
areas
107a, 107b, it eventually will reach a maximum concentration; thus thereby
triggering a restart of the upstream compressor system 101 and the gas
separation
system 102.
The minimum and maximum concentration can be individually defined and stored
in
the control device 10. An example minimum concentration could be 17.0% by
volume and an example maximum concentration could be 17.4% by volume, which
would correspond to a typical base inerting range.
A further example incorporates lower and upper limit values of 14.0% by volume
and 14.4% by volume, which would correspond to a typical full inerting range.
The
minimum and maximum concentrations can also be variably defined for day and
night mode in order to increase the fire protection efficiency, wherein the
day mode
represents a time with high human traffic within the enclosed area, requiring
a
higher oxygen concentration, and wherein the night mode represents a time in
which only few or no people enter into the enclosed area, which enables a
lower
oxygen concentration.
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The following description refers to the right branch of Fig. 6 which shows the
reciprocal action between fire detection, fire extinguishing ("fully inerted"
mode)
and refilling:
The fire detection can be realized with aspirating smoke detectors, whereby a
very practical, reliable and visually attractive fire alarm system can be
realized. If
a fire is detected within the enclosed area 107a, the detection signal is
transmitted from the fire alarm control panel 121 to the control device 10.
The
control device 10 consequently opens valve 106a and activates compressed gas
containers 105a to 105d to discharge via a collecting line 111 and valve 106a
so
that the oxygen-reduced gas mixture stored in the compressed gas containers
105a to 105d quickly enters into the enclosed area 107a and thereby
extinguishes
the fire.
As soon as the oxygen concentration in the enclosed area 107a reaches a
minimum,
the extinguishing or full inerting mode is ended by closing valve 106a. The
refilling
begins automatically or manually with the opening of valve 104 and the
starting of
the downstream compressor system 103.
Container pressure is measured continuously and the measurement data fed to
the
control device 10. The compressed gas containers 105a to 105d are refilled
until
the pressure reaches a preset maximum. In one preferential embodiment, the
pressure measurements are subject to temperature compensation. This is done
both by measuring pressure and measuring temperature in the compressed gas
containers 105a to 105d and by calculating a standardized pressure in
accordance
with thermodynamic formulas. The minimum and maximum pressure can be
individually defined and stored in the control device 10.
The refilling is completed by the control device 10 stopping the downstream
compressor system 103 and closing valve 104. The system then reverts to a mode
in
which the system reacts sensitively to fire alarm signals furnished in respect
of the
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51
enclosed area 107a, 107b, thus to a standby state for further rapid lowering
or full
inerting in the event of a re-ignition or another fire.
The invention is not limited to the embodiments of the oxygen reduction system
100
depicted schematically in the drawings but rather yields from an integrated
consideration of all the features disclosed herein.
Also particularly conceivable in this context is for another buffer storage to
be
provided directly at the outlet of the gas separation system in order to
temporarily
store the oxygen-reduced gas mixture provided at the outlet of the gas
separation
system.
Provided according to preferential realizations of the oxygen reduction system
100 is
making use of a gas separation system (nitrogen generator) which remains
stationary with the required additional downstream high pressure compressor
(compressor system 103) likewise being kept stationary or being provided so as
to
be mobile.
Should, however, the additional structural investment (high-pressure filling
lines,
valves, etc.) not be worthwhile for particular applications, a fully mobile
variant (gas
separation system 102, both compressor systems 101, 103) is of advantage.
In one alternative, a stationary gas separation system could be supported by a
mobile gas separation system since the stationary gas separation system would
otherwise need to be dimensioned larger just for a potential refilling in
order to
produce the necessary supply output. The possibility of providing two
stationary gas
separation systems (one for sustained flooding, one for refilling) is in
principle
likewise conceivable.
If (only) one, in particular stationary, gas separation system is provided, it
is
advantageous to be able to switch the nitrogen concentration of the oxygen-
reduced
CA 03006864 2018-05-29
52
gas mixture providable at the outlet of the gas separation system. Proven in
terms
of optimum supply conditions when being introduced into the room is a nitrogen
concentration of approx. 95% by volume; desirable for the filling, however, is
at
least 98% by volume, preferentially at least 99% by volume, in order to
optimize
the number of gas pressure containers.
In addition to the pressure of the gas stored in the compressed gas storage
(cylinder pressure), it is of advantage to monitor the temperature of the
compressed
gas storage (cylinder temperature). This not only serves the temperature-
compensated pressure measurement or filling respectively but also the
terminating
of filling upon a maximum temperature being exceeded so as to protect the
container valves. The temperature can be measured by means for example of
magnetic thermoelements on the outer wall of the cylinders. The temperature is
preferentially measured at least at two compressed gas storage points; i.e.
the
coldest and the warmest spot. The coldest and the warmest spot can be
determined
beforehand by testing or can be estimated based on the surrounding conditions,
e.g. on the basis of cool wall surfaces or radiators. The temperature at the
coldest
spot then serves the temperature-compensated pressure measurement/filling
whereas the measurement at the warmest spot seeks to prevent the exceeding of
a
maximum temperature potentially damaging to the container valves.
It is moreover of advantage to monitor the residual oxygen content at the
outlet of
the gas separation system in order for the nitrogen-reduced air to not be
conducted
into the compressed gas storage but rather diverted to the outside or into the
enclosed area in the event of inadmissibly low nitrogen concentration so as to
ensure the required purity.
CA 03006864 2018-05-29
53
List of reference numerals
control device
100 oxygen reduction system
101 upstream compressor system
102 gas separation system
103 downstream compressor system
104 first valve arrangement
105 compressed gas storage
105a-g compressed gas container
106, 106a-d third valve arrangement / third valve arrangement valves
107, 107a,b enclosed area
108 container valve
109, 109a,b second valve arrangement / second valve arrangement valves
110 first collecting line
111 second collecting line
112 backflow preventer
113 connector piece
114 sensor unit
115 temperature sensor
116 pressure sensor
117 oxygen sensor (area)
118 fire detector
119a, 119b alarm means
120 user interface
121 fire alarm control panel
122 oxygen sensor (gas separation system)
