Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CWCAS-167 CA 02538881 2006-03-10
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Method And Device For Identifying And Localizing A Fire
DESCRIPTION
The invention relates to a method for detecting and localizing a fire and/or
the origin
of a fire in one or more monitored areas as well as a device for realizing the
method.
The invention starts out from a fire detecting device having a sensor for
detecting a fire
parameter which is fed a representative volume of room or device air through a
suction
pipe system by means of a suction device such as a fan.
The term 'fire parameter" is to be understood as physical variables which are
subject to
measurable changes in the vicinity of an incipient fire, e.g. ambient
temperature, solid or
liquid or gaseous content in the ambient air (accumulation of smoke particles
or particu-
late matter or accumulating smoke or gases) or local background radiation.
Both procedures as well as fire detecting devices of the cited type are known
and
serve for prompt detecting of fires still in their incipient phase. Typical
areas of
application are either rooms containing high-quality or important equipment
such as,
for example, rooms containing computer systems in banks or the like, or even
just the
computer equipment itself. To this end, representative samples of the room air
or the
device cooling air are continually extracted, referred to in the following as
"air sample."
An appropriate means for extracting such air samples and feeding same to the
fire
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sensor, to the housing of the fire sensor respectively, is a suction pipe
system designed
as a system of conduits which are mounted, for example, below the ceiling of
the room
and lead to air intake openings in the housing of the fire sensor and which
sucks the air
samples in through air suction openings provided in the suction pipe system.
An
important premise in detecting an incipient fire at its earliest stage is that
the fire
detecting device continually extracts a sufficiently representative amount of
air without
interruption to supply the sensor sensing chamber. An applicable sensor here
would
be, for example, a point-based smoke sensor which measures the light turbidity
in a
sensor smoke chamber caused by particulate matter, or also a scattered light
sensor
integrated in the intake path which detects scattered light caused by smoke
particles at
a center of the sensor.
Methods and devices using a plurality of suction pipe systems to detect and
localize
sources of fire in one or more monitored areas are known from the prior art
and have
been developed based on the fact that, for example, it is very difficult for
firefighting
crews to localize the source of a fire in large halls, office buildings,
hotels or ships.
One single smoke suction system having a single fire-detecting unit may -
subject to
national regulations - monitor an area of up to 2000 m2, which may also
comprise
several rooms. In order to enable an operative alarm site to be quickly
localized,
requirements have been defined such as those set forth, for example, in
Germany's
"Guidelines for Automatic Fire Reporting Installations, Planning and
Construction"
(VdS 2095). Pursuant thereto, a plurality of rooms may only be grouped
together into
one alarm area when the rooms are adjacent, the access to same can be readily
seen
at a glance, the total surface area does not exceed 1000 mZ, and there are
clear visual
alarm indicators at the fire alarm monitoring station which, in the event of a
fire alarm,
indicate the area where the fire is located.
While devices for detecting fire which operate on an aspirative principle, in
which a
plurality of areas to be monitored are connected by one individual smoke
suction
system, offer the advantage of the earliest possible detection of fire, there
is no
guarantee that the site of the fire can be localized in such a commonly-shared
smoke
suction system monitoring a plurality of areas. This is due to the fact that
the individual
air samples, each representing the room air from one individual monitored
area, are fed
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to the sensor for detecting a fire parameter after having been mixed together
in the
jointly-shared suction pipe system. All the sensor can thus establish is that
a fire broke
out and/or is imminent in one of the areas being monitored. In order to be
able to
additionally ensure a localization of the seat of the fire in one of said
monitored
areas, it is usually necessary to feed each air sample extracted from each
individual
monitored area to another sensor of a separate suction pipe system in order to
detect
a fire parameter. Yet when monitoring a plurality of monitored areas, this has
the
disadvantage that the corresponding number of suction pipe systems must be in
place, which involves a very complex implementation of the one or more
aspirative fire
detection system(s) both structurally as well as financially.
FR 2670010 Al discloses alarm boxes which serve to identify the smoke-sucking
joint
in a branched suction pipe system. These alarm boxes consist of a point-based
smoke
sensor built into a housing with a cable threading to connect the inlet and
outlet pipes
and a signal light on its cover. Yet disadvantageous to this construction is
that because
of their size, design and price, these alarm boxes cannot be employed at each
individual air intake opening.
Known further from WO 00/68909 is a method and a device for detecting fires in
monitored areas by means of which the source of a fire can be localized. This
method
utilizes an appropriate device in each monitored area comprised of two
crossing pipes,
into which one or more fans continually suck in air from the monitored areas
through
suction openings disposed in the pipes and feed same to at least one sensor
for
detecting one fire parameter per pipe. The localization of the seat of the
fire thereby
follows from the responding of the two sensors allocated to the crossing
pipes. A
plurality of areas is monitored by such pipes arranged as a matrix of columns
and rows,
where appropriate by one cumulative sensor each for the column and row
arrangement.
A disadvantage to this known device, however, is the very substantial
installation outlay
for the matrix-like system of pipes.
Known from the German DE 3 237 021 C2 patent specification is a selective
gas/smoke
detection system having a plurality of suction lines connected separately to
various
measuring points in an area to be monitored in order to withdraw samples of
air or gas at
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said measuring points. Here, a gas or smoke sensor connected to these lines
reacts to
the presence of a specific gas in the sample upon a fixed threshold being
exceeded and
emits a detection signal which controls an indicator and/or alarm circuit.
Shut-off valves
which are cyclically and periodically energized in a controlled loop are
furthermore
arranged on the individual suction lines. Detecting fire with this gas/smoke
detection
system ensues in that in the absence of a detection signal, the control unit
sets the
shut-off valves such that all the suction lines are simultaneously in open
connection
with the sensor, and upon a detection signal being received, switches them
over to a
sensing mode in which the suction lines are conventionally brought into open
connection with the sensor consecutively or in groups. This function for
detecting the
origin of fire presupposes, however, that the sensor can be brought into
connection
with each area to be monitored by way of individual and selectively-opened
feed lines.
This inherently means having to install an extensive system of pipes in order
to create
these individually selectable connections. Likewise disadvantageous is the
high cost of
installing the necessary suction lines.
WO 93/23736 further makes known an air pollution/smoke detection device based
on a
network-like configured suction system having a large number of sampling sites
at which
gas is extracted from each room to be monitored. This pollution/smoke
detection device
has a plurality of inlet ports connected to the grid-like suction system and
monitored
individually. Under normal circumstances, all these inlets remain open until
the
detection device detects pollution/smoke. Selectively closing the inlet ports
then allows
the localizing and detecting of a fire zone. But the operation of this
detection device also
requires an extensive installation of suction lines to form a grid-like
structure in order to
ensure reliable detection of a fire source. Here as well, the disadvantage to
this known
device lies in the high installation outlay for the system of pipes.
Further known from DE 101 25 687 Al is a device for detecting and localizing a
source of fire in one or more monitored areas. The device comprises a main
sensor
for detecting a fire parameter with an intake unit continuously feeding
samples of the
ambient air from the monitored areas through a line disposed with intake ports
arranged in each monitoring chamber. One sub-sensor each is thereby provided
on or
in the vicinity of at least one suction opening per monitored area, which is
switched on
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by a switch-on signal transmitted by a controller in accordance with a
detection signal
emitted by the main sensor. The switched-on sub-sensor thereby serves in the
detecting of the source of the fire and thus for localizing the fire source
from the
plurality of monitored areas. This device known from the prior art has the
disadvantage
that due to the number of sub-sensors employed, the costs associated with the
fire
detecting device are relatively high and furthermore necessitates a relatively
complex
wiring of the sub-sensors when installing the device.
One task addressed by the present invention is to provide a simple and
economical
device and a method for detecting sources of fire which combines the
advantages of
known smoke and gas suction systems - active intake and concealed mounting -
with the advantage of localizing each individual suction opening and thus
detecting an
actual seat of fire or actual gaseous impurity as occurs when a fire develops.
A further
task addressed by the present invention consists of providing a fire-
extinguishing
system comprising an aspirative fire detection device which affords both
reliable fire
detection as well as localization of the site of a fire from a plurality of
monitored areas,
whereby the fire detection device can dispense with the need for a plurality
of suction
pipe systems connecting the individual monitored areas to one sensor in order
to
detect a fire parameter.
According to the invention, this task is solved by a method of the type
described at the
outset having the following procedural steps: air samples representative of
each
individual monitored area are extracted from said individual monitored areas -
preferably
continuously - through a common suction pipe system; at least one fire
parameter is
established for the air samples sucked in through the suction pipe system by
the at
least one sensor provided for detecting fire parameters; the suctioned air
samples within
the suction pipe system are blown out by means of a blower or suction/blower
device;
representative air samples of the room air from each of the individual
monitored areas
are re-extracted through the suction pipe system for as long as necessary
until the at
least one sensor re-detects a fire parameter in the air samples; the time
elapsed before
the re-detecting of the fire parameter in the previously re-extracted air
samples is
evaluated in order to localize an actual fire or the site of an imminent fire
from one of
the many monitored areas; and a signal is emitted which indicates the
development
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and/or presence of a fire in one or more of the monitored areas, wherein the
signal also
contains further information for a precise localization of the fire in the one
or more
monitored areas.
The underlying technical problem of the present invention is further solved by
a device
comprising a suction pipe system connecting the plurality of areas to be
monitored
which communicates with each individual monitored area by means of at least
one
suction opening, a suction device to extract representative air samples from
the
individual monitored areas by means of the suction pipe system and the suction
openings, and at least one sensor for detecting at least one fire parameter in
the air
samples extracted through the suction pipe system, whereby the device is
characterized by a blowing device for blowing out the air samples sucked into
the
suction pipe system when the at least one sensor detects at least one fire
parameter in
the extracted air samples, and by at least one indicator element which
identifies the site
of a fire in one of the monitored areas and/or by a communication device which
transmits information on the development and/or presence of a fire in one or
more of
the monitored areas and on the precise location of the fire in the one or more
monitored
areas to a location remote of the device.
The task of applying the technique is solved by utilizing a device in
accordance with the
invention as a fire detection component of a fire extinguishing system for
activating the
introduction of a fire extinguishing agent in one of the monitored areas.
An essential aspect of the present invention relates to the fact that based on
the
already widespread use of installations for smoke or gas suction systems -
also known
as aspirative monitoring systems - the only technical approach that makes
sense is a
simple and economical retrofitting to achieve individual detection of fire
sources or gas
impurities under the criteria of existing norms. At the same time, a situation
where the
associated retrofitting runs into substantial construction and operating costs
in order to
meet desired safety standards must be avoided. The particuiar advantages of
the
invention are seen in that not only are the requirements of detecting and
localizing a
fire and/or the onset of a fire in one of a plurality of monitored areas
attainable following
simple retrofitting of existing aspirative systems together with concurrent
low operating
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costs utilizing a very easy to realize and thereby very effective method, but
the
inventive method's localizing of the site of a fire also opens up new
applications for
smoke suction systems. This thus dispenses with the need for, as an example, a
plurality
of point-based fire alarms as used to date in buildings having a plurality of
individual
rooms. The inventive method affords the reliable detection of a fire or the
onset of a fire
in a monitored area and for this monitored area to be localized from a
plurality of
monitored areas through the use of just one suction pipe system, one sensor to
detect
a fire parameter, and one suction/blowing device. Doing so does away with the
need for
an elaborate installation of a plurality of suction pipe systems in
combination with a
plurality of sensors, which clearly and advantageously reduces the structural
complexity of the installation or the retrofitting of a plurality of
monitoring areas with
such a fire detection device. Because the fire detection and localization is
aspiratively
based, the present method is extremely sensitive and in particular independent
of
spatial heights or high air speeds within the individual monitored areas. High
ceilings
or higher air speeds lead, for example in air-conditioned areas, to a vigorous
diluting
of smoke. The high detection sensitivity of the inventive fire detection and
localization
method is to a large extent independent of these parameters. The inventive
method
moreover offers the advantage that a fire and/or the onset of a fire can be
reliably
identified and located independent of disturbances such as dust, dirt,
humidity or
extreme temperatures in the individual monitored areas. The method according
to
invention also makes possible the use of only one single suction pipe system
which
can be integrated virtually invisibly into the building's architecture so that
aesthetic
interests can be commensurately taken into full account.
Blowing out the air samples sucked into and present within the suction pipe
system
after the sensor for detecting fire parameters detects at least one fire
parameter in the
air sample sucked through the suction pipe system occasions fresh air to then
fill the
entire suction pipe system; i.e., air which definitely no longer exhibits any
fire
parameter. Following the air samples being blown out, the suction pipe system
re-
extracts air samples representative of the room air of each individual
monitored area
from the individual monitored areas. An essential aspect of the method
according to the
invention is now the measuring of the transit time and/or specific transit
time values
until the sensor once again detects a fire parameter in the air samples sucked
through
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the commonly-shared suction pipe system. This transit time is subsequently
evaluated
in order to localize the site of the fire or the site where a fire is
developing, based on
the fact that each individual monitored area is at a certain distance from the
sensor and
also exhibits a transit time dependent on the suction pipe system.
In realizing the above-described method, the device according to the invention
allows for
providing a suction device to extract representative air samples of the room
air within the
individual monitored areas from each individual monitored area through the
suction pipe
system communicating with each individual monitored area via suction openings,
and
subsequently feed same to the sensor. Of course, to lower the probability of
sensor
failure, a plurality of sensors can also be used for detecting a fire
parameter with the
device according to the invention. It would also be conceivable to use one
sensor for
one specific fire parameter and another sensor for another fire parameter. The
device
in accordance with the invention is particularly advantageous in terms of
maintenance
and service. Utilizing only one sensor, one suction device and one blowing
device,
which can be arranged in a separate area external the monitored areas and thus
readily accessible to maintenance personnel, not only clearly reduces overall
maintenance costs, but also the maintenance and service personnel do not need
to
enter the monitored areas, which is a particularly important aspect in the
case of
cleanrooms, ship cabins or prison cells. In a particularly preferred
embodiment, the
device according to the invention additionally exhibits a communication
device, by
means of which information is transmitted to a site remote of the device
regarding the
emergence and/or presence of a fire in one or more of the monitored areas and
regarding the precise location of the fire in the one or more monitored areas.
A site
remote of the device in this context can be for example a fire alarm
monitoring station or
a control center for task force crews. The communication device thereby
enables for
example either a wired or wireless transmission of a corresponding signal
containing
the relevant information in the event of a fire to an associated receiver.
Said
communication device can itself be controllable, of course, for instance in
order to
change or test an operational state of the device. IR technology would also be
applicable as a conceivable communication medium.
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Preferred embodiments of the invention related to the method are indicated in
subclaims 2 to 9 and related to the device in subclaims 11 to 20.
For instance, it is particularly preferred in terms of the method for the flow
rate of an air
sample in the suction pipe system to be determined as the respective air
samples are
being withdrawn from the individual monitored areas. This flow rate then
serves in
calculating the time necessary to fully blow out the air samples located in
the suction
pipe system. The determination or measurement of the flow rate can thereby be
done
either directly or indirectly; i.e., for example based on device parameters
such as the
output of the suction device, the effective flow cross-section of the suction
pipe system
and the respective diameters to the suction openings disposed along the
suction pipe
system. A direct measurement is possible with a pluraiity of different flow
rate-
measuring methods known in the art. It would be conceivable here to make use
of, for
example, hot-wire or hot-film anemometry. Calculating the time necessary for
the
blowing device to fully blow the air samples out through the suction pipe
system can
advantageously realize a minimizing of the blow-out time and localizes the
site of the
fire in the shortest possible time.
A particularly advantageous realization of the inventive method provides for
the
process step of blowing out the extracted air samples present in the suction
pipe
system to further comprise the process step of determining the flow rate
during this
blowing out in order to calculate the time necessary to fully blow the air
samples out of
the suction pipe system. Here, note is made of the fact that suctioning and
blowing out
very probably take place at different flow rates, even if the same fan is used
for both
suctioning and blowing, since fans normally exhibit different characteristic
curves for
these two modes of operation. Based on the flow rate determined during the
blowing
out, the time which is necessary to fully blow all the air samples out of the
suction pipe
system is then calculated, whereby this calculated time is a very exact value.
It is furthermore particularly preferred to determine the flow rate of the air
samples in
the suction pipe system during the renewed extraction of the respective air
samples
from the individual monitored areas. The determined flow rate thereafter
serves as the
basis for calculating the transit time of the respective air samples
representative of the
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room air of the individual monitored areas during the renewed extraction of
the
respective air samples from the individual monitored areas. This embodiment of
the
method achieves a particularly high reliability and accuracy to the
localization of the
site of the fire. Of course, transit time occurring with the renewed
extraction of the
respective air samples from the individual monitored areas can also be
calculated on
the basis of, for example, the flow rate determined during the continuous
extraction of
the respective air samples from the individual monitored areas or on the basis
of
theoretical values.
Air sampling according to the inventive method is realized by means of a
suction
device, whereby the subsequent re-extraction of air samples from the
individual
monitored areas ensues with a suction line which is reduced in comparison to
the
suction line used for the previously performed air sample extraction. In
particularly
preferred manner, this thus achieves a longer transit time for the re-
suctioning and the
difference in transit times between the different suction openings also
increases. As a
result, a more reliable correlating of measured transit time to specific
monitored area is
attained. Allowing for a transit time measurement tolerance of, for example,
0.5 to 2
seconds would be conceivable. In order to avoid two neighboring suction
openings
overlapping in transit time tolerance ranges, which would result in
localization of a fire no
longer being possible, the re-extraction is therefore run at a lower suction
line. Thus, this
embodiment advantageously increases the accuracy of the transit time
measurement.
Yet it is, of course, also conceivable - additionally or in place of - to
increase the
sampling rate for the fire parameter in the sensor during re-suctioning, which
likewise
increases the accuracy of the transit time measurement.
A particularly preferred realization of the method according to the invention
further
provides for an auto-adjusting procedure, comprising the following process
steps: a fire
parameter is artificially produced at a suction opening at the most distant
monitored
area from the at least one sensor over the entire time of the auto-adjusting
procedure;
air samples are suctioned from the individual monitored areas through the
commonly-
shared suction pipe system until the at least one sensor detects the
artificially-generated
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fire parameter in the extracted air samples; the extracted air samples located
within the
suction pipe system are blown out by means of a blowing or suctioning/blowing
device;
new air samples are again suctioned out of the individual monitored areas
through the
suction pipe system at least until the at least one sensor re-detects an
artificially-
generated fire parameter in the air samples; the transit time elapsed until
the re-
detection of the artificially-generated fire parameter of the re-extracted air
samples is
evaluated in order to determine the maximum transit time for the suction pipe
system;
the transit times for the respective air samples representative of the room
air of the
individual monitored areas are calculated based on the previously-determined
maximum
transit times and the configuration of the suction pipe system, in particular
the distance
between the suction openings, the diameter to the suction pipe system and the
diameter of the suction openings; and the calculated transit times for the
respective air
samples are stored in a table. The advantage to this embodiment, using the
auto-
adjusting procedure, is particularly based on no longer needing to measure the
flow
rate of the air samples in the suction pipe system. In this regard, it is
provided to put the
fire detection device into operation in a self-learning mode, generate smoke
at the most
distant suction opening, and to measure the transit time with the process
steps of
suctioning, biowing out and re-suctioning. Based on the maximum transit time
and the
specific pipe configuration, the transit times for all suction openings can
then be
calculated. This calculation can be performed by the fire detection device
itself or
externally, for example on a laptop computer. The calculated fire detection
device
transit times are then subsequently stored to a table.
A particularly preferred embodiment of the method according to the invention
making
use of the auto-adjusting procedure further provides for utilizing a
correcting function on
the calculated transit times stored in the table in order to update the
transit time values
occurring for the individual monitored areas. Doing so takes into account that
the suction
pipe system and/or the suction openings may gradually get dirty over time,
which would
go hand in hand with a gradual change in the flow rate. A correcting function
can thus
be used to calculate current transit times from the transit times stored in
the table.
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Evaluating the transit times in the inventive method prior to the renewed
detecting of
fire parameters for the re-extracted air samples preferably ensues by
comparing the
resulting transit time with respective transit times computed theoretically
for the
individual monitored areas. Conceivable as applicable parameters on which the
theoretically-calculated transit times can depend include the length of the
respective
sections of the suction pipe system between the sensor and the suction
openings of the
respective monitored areas, the effective flow cross-section of the suction
pipe system
and/or the respective sections of the suction pipe system between the sensor
and the
suction openings of the respective monitored areas, and the flow rate of the
air samples
in the suction pipe system and/or in the respective sections of the suction
pipe system
between the sensor and the suction openings of the respectively monitored
areas.
However, other parameters on which the theoretically-calculated transit time
can
depend are, of course, also conceivable.
One advantageous embodiment to the inventive device is provided by the device
additionally exhibiting a controller to enable a time-coordinated controlling
of the suction
device and the blowing device in agreement with a signal emitted by the at
least one
sensor when the sensor detects at least one fire parameter in the air samples.
Said controller is preferably configured such that the suction device is first
set to effect
a continuous withdrawal of air samples representative of the room air from the
indivi-
dual monitored areas through the common suction pipe system. Should the sensor
then
detect at least one fire parameter in the extracted air samples, and thus send
the
corresponding signal to the controller, the controller sends a corresponding
signal to the
suction device in response thereto in order to shut off same, whereby at the
same time
or directly thereafter, a further signal is issued by the controller to the
blowing device to
switch on said blowing device in order to blow out the extracted air samples
located
within the suction pipe system. In accordance with the invention, it is
thereby provided
for the controller to send another signal to the blowing device after a fixed
time in order to
shut if off, whereby at the same time or directly thereafter, a signal issues
from the
controller to the suction device in order to effect a renewed continuous
extraction of air
samples representative of the room air of the individual monitored areas from
the
individual monitored areas through the suction pipe system. The fixed time
during
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which the blowing device is active is either a time determined theoretically
on the basis
of device parameters and stored in a memory, or is a time determined by means
of a
measured flow rate value to an air sample in the suction pipe system during
the continuos
extraction of the respective air samples from the individual monitored areas.
A particularly preferred embodiment of the inventive device further provides
for a
memory device in which transit time values can be stored. The values saved in
this
memory can be, for example, transit times determined during an auto-adjusting
procedure
based on a maximum transit time and the pipe configuration.
Particularly preferred is for the device according to invention to exhibit at
least one
smoke generator arranged near a suction opening and which can artificially
generate a
fire parameter for the purpose of setting and testing the fire detection
device. It is thus
possible when putting the fire detection device into operation to set it in a
self-learning
mode to measure the smoke generated by means of the smoke generator at the
most
distant suction opening and the transit time of the artificially-generated
smoke, the
artificially-generated fire parameter respectively. This thus enables the
measuring of a
maximum transit time, based on which and given knowledge of the pipe
configuration,
the transit times for all suction openings can be calculated. It is, of
course, also
conceivable here for the fire generator to be arranged at another suction
opening,
respectively a plurality of smoke generators provided at different suction
openings.
In one possible realization, the device according to the invention further
comprises a
sensor for measuring the flow rate of the air samples in the suction pipe
system. In so
doing, it is advantageously possible to determine the flow rate of the
extracted air
samples in the suction pipe system, in order to calculate based on same the
time
necessary for the blowing device to completely blow out the air samples
present in the
suction pipe system. The flow rate determined with the help of the sensor can
moreover
serve in calculating the transit times of the respective air samples
representative of the
air room of the individual monitored areas during the re-extraction of the
respective air
samples from said individual monitored areas. Examples of sensors for
measuring the
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flow rate are known in the prior art and include sensors based on the
principle of hot
film and/or hot wire anemometry. It would furthermore be conceivable to
determine the
flow rate based on theoretical device parameters instead of measuring the flow
rate with
a sensor. Likewise conceivable here would also be only switching on the sensor
to
measure the flow rate for the duration of one self-learning mode upon device
start-up.
Particularly preferred is to provide a processor for evaluating a signal
emitted by the at
least one sensor when the sensor detects a fire parameter in an air sample and
a control
signal emitted by the controller to the suction device and/or blowing device.
The
processor is thereby advantageously configured such that it determines the
transit time of
the air sample representative of the respective room air of the individual
monitored areas
by the renewed continuous extraction from each individual monitored area
through the
suction pipe system based on the signal, in order to thus localize the site of
the fire or
the developing fire. Evaluating the resulting transit time is thereby
performed in the
processor by comparing the resultant transit time with respective transit
times
computed theoretically for the individual monitoring areas. The theoretically-
computed
transit times can be dependent on, for example, the length of the respective
sections of
the suction pipe system between the sensor and the respective monitored areas,
the
effective flow cross-section of the suction pipe system and/or the respective
sections of
the suction pipe system between the sensor and the respective monitored areas,
and
the flow rate to the air sample in the suction pipe system and/or in the
respective
sections of the suction pipe system between the sensor and the suction
openings of the
respective monitored area. By analyzing the transit times, localizing the site
of the fire
becomes possible.
An advantageous embodiment of the inventive device provides for the diameters
and/or the cross-sectional shape to the individual suction openings to be
configured
contingent upon the respectively monitored areas.
Conceivable here in terms of the monitored areas which are disposed farther
from the
suction/blowing device would be to utilize suction openings with larger cross-
sections
CWCAS-167 CA 02538881 2006-03-10
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than the monitored areas which are closer to the suction/blowing device. The
respective distance of the monitored areas from the suction/blowing device is
defined
by the distance an air sample must traverse the suction pipe system from the
respective suction opening in the respective monitored area to the suction
device. The
respective cross-sectional shape or cross-sectional size to the individual
suction
openings are designed in such a way that they take the drop in pressure
occurring in
the suction pipe system into account. The inventive embodiment to the suction
openings
thereby enables the inventive device to be equally sensitive in terms of fire
detection and
fire localization for each of the plurality of monitored areas. In one
possible realization,
the individual suction openings in the suction pipe system could be adapted to
given
conditions following installation of the pipe system in the building. It would
be
conceivable, for example, to initially configure all suction openings to be
the same size,
having the same cross-sectional shape respectively, whereby the respective
suction
openings are defined post-installation by affixing a corresponding diaphragm
aperture
to the suction openings. Applicable here would be, for example, a perforated
film or
perforated clip, whereby the hole size in the film or the clip is adapted to
the given
spatial circumstances. Of course other embodiments are just as conceivable.
Also possible
would be for the suction pipe system to be configured such that the cross-
sectional
shape to the suction pipe system will vary according to installation
conditions.
A particularly advantageous realization provides for configuring the suction
device and
the blowing device together as one blower. Said blower is thus designed such
that it
changes the direction it conveys air in response to the control signal from
the controller.
This thus allows achieving a further reduction in the number of components
comprising
the inventive device, which in turn advantageously lowers the costs of
manufacturing
the device in accordance with the invention.
In order to further reduce the number of components comprising the fire
detection and
fire localization device according to invention, the suction device and the
blowing device
are advantageously configured together as one blower, whereby said blower is
one
affording reversal of rotation.
CWCAS-167 CA 02538881 2006-03-10
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A further realization of the device according to invention in which the
suction device
and the blowing device are configured together as one blower provides for the
blower
to be a fan having the appropriate ventilation flaps so as to change the
direction it
conveys air. Other embodiments are of course also conceivable here.
As indicated above, the inventive device comprises indicator elements which
identify the
site of a fire in one of the monitored areas. These indicator elements can be
in the
proximity of the entrances to these areas or in the proximity of the fire
detection device
respectively. The communication means or one input component for the
connection to a
communication bus with a fire alarm central station serves to forward
information on the
site of a fire to the central station, in order to display it, for example, in
plain text on the
control panel (e.g. "fire in Area X"). Additionally to or in place of the
indicator elements,
the inventive device can further comprise a communication device which
transmits
information regarding the onset and/or presence of a fire in one or more of
the
monitored areas and regarding the precise location of the fire in the one or
more
monitored areas to a site remote of the device, such as, for example, to a
fire alarm
central station or a control center for task force crews. Depending upon
application, the
communication device thereby preferably affords either the wired or wireless
possibility
of emitting an appropriate signal to at least one associated receiver disposed
at a
distance from the inventive device when the need arises. Said communication
device
can, of course, also itself be externally controllable, for instance in order
to change or
test an operational state of the device. IR technology would also be
applicable as a
conceivable communication medium.
The following will make reference to the drawings in describing a preferred
embodi-
ment of the inventive device in greater detail.
Shown are:
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Fig. 1 a schematic representation of an embodiment of the inventive device
for detecting a fire and localizing the fire in one monitored area out of
a plurality of monitored areas; and
Fig. 2a, b graphic representations of the signal dynamics.
Figure 1 is a schematic representation of a preferred embodiment of the
inventive
device for detecting a fire and for localizing the fire within one monitored
area (R,, R2,_..,
Rn) from a plurality of monitored areas (R,, R2,.., Rn). The inventive device
according to
Fig. 1 involves a centrally-arranged, aspirating fire detection device able to
precisely
localize the site of a fire. In the embodiment as depicted, the device is used
to monitor
four separate monitored areas (R,, R2, R3, R4). It is hereby provided for each
one air
sample (6), representative of the room air of the respective monitored areas
(R,,_..,R4)
to be continuously extracted from the respective monitored areas (R,,..., R4)
through a
common suction pipe system (3). To this end, a suction device (5) configured
as a
blower is provided at one end of the suction pipe system (3). The air samples
(6)
extracted through the common suction pipe system (3) by the suction device (5)
are
conveyed to a sensor or a plurality of sensors (7) to detect one or more fire
parameters.
It would be conceivable in this regard to arrange the suction device (5)
together with the
sensor (7) in one common housing (2).
Sensor (7) serves to analyze the air samples (6), each representative of the
room air of
the monitored areas (R,,.,.,R4) to be monitored, as suctioned through the
suction pipe
system (3) for a fire parameter. Applicable as sensor (7) would be any of the
devices
known in the prior art. In the event of a fire breaking out in one of
monitored areas
(R,,. R4) or the room air of a monitored area (R,, , R4) containing fire
parameters and
sensor (7) detects said fire parameters in the extracted air samples (6), same
emits the
corresponding signal to a controller (9).
In response to this signal, controller (9) emits the appropriate control
signal to suction
device (5) so as to switch it off. At the same time or immediately thereafter,
a further
CWCAS-167 CA 02538881 2006-03-10
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signal is emitted by controller (9) to a blowing device to activate same. Said
blowing
device (8) is advantageously arranged such that when in operation, it blows
out the air
samples (6) already extracted and still present in the suction pipe system
(3). In
particularly advantageous fashion in the embodiment as depicted, the suction
device (5)
and the blowing device (8) are configured together as one blower (11) which
changes its
air-conveying direction in response to a signal emitted by controller (9). As
an example,
the blower could be a reversing-rotation fan, yet also conceivable would be a
blower (11)
having a fan with ventilation flaps. When biowing out the suction pipe system,
blowing
device (8) brings in fresh air, i.e. outside air, toward the individual
suction openings (4)
of the respective monitored areas (R,, R4). Said fresh air thereby displaces
the air
samples (6) still within the suction pipe system (3) which are, for example,
blown back
out into monitored areas (R,, , R4) through the respective suction openings
(4).
In accordance with the invention, controller (9) is designed such that it
sends a further
signal to blowing device (8) after all the air samples (6) are blown out of
the suction pipe
system (3) in order to switch same off. At the same time or immediately
thereafter,
controller (9) reactivates suction device (5). By so doing, air samples (6)
representative
of the room air of the individual monitored areas (R, ... R4) are re-extracted
from the
individual monitored areas (R,,...,R4) through the suction pipe system (3) and
conveyed
to sensor (7). Said sensor (7) detects the presence of fire parameters in the
extracted
air samples (6) after a specific period of time following the restart of
suction device (5).
The time elapsing between the renewed starting of suction device (5) and the
initial
detecting of fire parameters in the re-extracted air sample (6) defines the so-
called
transit time, which serves as the basis for localizing the seat of the fire.
A processor (10) is provided to evaluate the transit time determined as such
which
compares the transit time determined with transit times calculated
theoretically. The
theoretically-calculated transit times stand in direct correlation to the
distance of
sensor (7) from suction openings (4) of the individual monitored areas (R,, ,
R4),
since they depend on at least one of the following parameters: length of the
suction
pipe system (3) between sensor (7) and the suction openings (4) of the
respective
CWCAS-167 CA 02538881 2006-03-10
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monitored areas (R,,.,R4); the effective flow cross-section of the suction
pipe system
(3) between sensor (7) and the suction openings (4) of the respective
monitored areas
(R,,.., R4); and the flow rate to the air sample (6) within suction pipe
system (3).
Thus, with knowledge of at least the length of the respective sections of the
suction
pipe system (3) between sensor (7) and the suction openings (4) of the
respective
monitored areas (R,, , R4) and the flow rate of the air samples (6) through
suction
pipe system (3), it is possible to localize the site of the fire based on the
transit time
as measured.
The preferred embodiment of the present invention further comprises a sensor
(12) to
measure the flow rate of the air samples (6) in the suction pipe system (3).
The
measured flow rates are used by processor (10) to evaluate the measured
transit
times. It is however also possible to forgo a sensor (12) for measuring flow
rate,
whereby the flow rate is determined on the basis of device parameters such as,
for
example, the effective flow cross-section of the suction pipe system (3),
suction
capacity of the suction device (5), cross-sectional shape and cross-section
opening
to the suction openings (4).
It is also possible for the fire detection device to determine a transit time
in a self-
learning mode and calculate all respective transit times from same, storing
them in a
memory-saved table.
Figures 2a and 2b each show a graphic representation schematically depicting
the signal
emitted by sensor (7) or controller (9) for controlling suction device (5) and
blowing
device (8). The x-axis here represents the time while the y-axis represents
the signal of
sensor (7) or the control signal of controller (10). In the toto t, time
interval, suction
device (5) is controlled by controller (10) so as to be continually active;
i.e., extracting
air samples (6) from the monitored areas (R,,..., R 4). A dotted line is used
to depict this
process in Fig. 2b. At time point t,, sensor (7) detects the occurrence of a
fire para-
meter in the extracted air samples (6). In response to the signal emitted by
sensor (7) at
time point t,, suction device (5) is switched off and blowing device (8)
simultaneously
CWCAS-167 CA 02538881 2006-03-10
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activated. The blowing-out period corresponds to the period from t, to t2,
which is a
time dependent upon the output of blowing device (8) and on specific
parameters of
the suction pipe system (3).
After all the air samples (6) within suction pipe system (3) are blown out at
time t2,
controller (9) deactivates blowing device (8) and simultaneously re-activates
suction
device (5). Sensor (7) is then again fed air samples (6) accordingly. Decisive
for
localizing the site of the fire is now the transit time Ot, to A t4. Transit
time (A t,,... A t4)
corresponds to the period of time from time point t2, at which suction device
(5) is re-
activated, to time point t3 to t6, at which sensor (7) again detects a fire
parameter in
the extracted air samples (6). Said transit times (A t,... A t4) are specific
to the
individual monitored areas (R,,..., R4) and serve the subsequent analysis of
localizing
the site of the fire.
