Note: Descriptions are shown in the official language in which they were submitted.
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Catalytic heater
FIELD OF THE INVENTION
The present invention relates to a catalytic heating system comprising a main
catalyst
for flameless catalytic burning of fuel gas and a triggering system for
initiating the
catalytic burning, the triggering system comprising an electrical power source
electri-
cally connected to an electrical resistance heater for heating a catalyst
portion to a
temperature necessary for triggering the catalytic burning.
BACKGROUND OF THE INVENTION
Catalytic heating for hot water supplies is well known in the art and
described, for
example, in US patents 4,510,890 by Cowan, 4,886,017 by Viani, and 5,709,174
by
Ledjeff et al. Though, burning of fuel by combustion is easily started by a
piezo spark,
it is very difficult to start by such simple means, especially if the system
has small
dimensions. In order for the flameless catalytic oxidation of the fuel to
start, a tem-
perature of typically 150 C has to be achieved first for the catalytic
burning. Therefore,
as a starting mechanism, one common method, as also described in US patent
5,709,174 by Ledjeff, is to burn fuel in a flame in a combustion chamber prior
the
catalytic process in order to provide initial heat to start the catalytic
process.
Using flame combustion as a starting mechanism for a catalytic heater implies
a num-
ber of precautions to be taken. As the temperature for methane combustion
reaches
1300 C, the chamber needs a relatively large size for not leading to damage in
the ad-
jacent heat exchanger. Therefore, typically, the combustion products are mixed
with
air in order to reduce the temperature. The problem is described in US
4,886,017 by
Viani. A disadvantage of such systems may be seen in the provision of a
combustion
chamber, Which makes it difficult to provide small systems, for example
portable sys-
tems, when using a combustion chamber. Another disadvantage is the fact that
com-
bustion only starts if the oxygen content is between 2% and 9% in the case of
propane
or butane as fuel. However, this oxygen-poor mixture results in incomplete
burning,
such that the combustion products have a strong smell, which requires that
these burn-
ers also have an afterburner for burning the remaining fuel in the combustion
gases.
.00MI'MATI'M COPY.
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All in all, this kind of systems are generally large and expensive and not
suited for
portable devices.
An alternative starting mechanism is disclosed in US 4,886,017 by Viani, where
an
electrical resistance heater is embedded in the catalyst material having
between 0.01%
and 10% by weight of a catalytic metal on a solid support material of divided
form, for
example ceramics. This solution avoids the need of a combustion chamber and
has the
potential for small systems. However the need for heating the ceramic based
catalyst
implies a rather strong electric source. If used for a portable system, which
is interest-
ing for hikers and military purpose, relatively heavy batteries limit the
usefulness. It
would be desirable to provide a starting mechanism that can be made smaller
for port-
able systems.
DESCRIPTION / SUMMARY OF THE INVENTION
It is therefore the object of the invention to provide a catalytic heating
system with a
starting mechanism that is easy to implement in small systems having a minimum
weight.
This object is achieved with a catalytic heating system comprising a main
catalyst for
flameless catalytic burning of fuel gas and a triggering system for initiating
the cata-
lytic burning, the triggering system comprising an electrical power source
electrically
connected to a metallic catalyst portion. As electric current flows through
the metallic
catalyst portion, it is in itself heated as an electric resistance heater to a
temperature
necessary for triggering the catalytic burning.
The term catalyst portion means a portion of a catalyst, thus the catalyst
portion itself
is made of an electrically conducting, metallic catalytic material, for
example the same
material as the main catalyst. By using electrical current for direct heating
of a catalyst
portion, reaction starts as soon as the resistance heating achieves the
temperature for
initiating the catalytic reaction, because the oxygen enriched fuel gas is in
direct con-
tact with the heated catalyst. As soon as the reaction starts, the reaction is
transferred
to the main catalyst.
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In contrast to prior art document US 4,886,017 by Viani, there is no need for
heating a
non-catalytic electric resistance heater first and then transferring the heat
to the cata-
lyst. Especially in connection with prior art, if the main component of the
catalyst is
ceramics, as in US 4,886,017 by Viani, there is a need for relatively large
amounts of
current in order to provide enough energy for the reaction to start. In
contrast thereto,
according to the invention, no heat transfer is necessary to any catalyst, as
the catalyst
portion itself is heated by the current. This implies that only relatively
small amounts
of current are needed for the triggering process, especially if the catalyst
portion is
small. The advantage thereof is that power supplies in the form of
batteries/capacitors
can be made smaller and lighter without compromising the endurance of the
batteries,
which is advantageous in especially portable systems.
A flameless catalytic heating element - without initial flame combustion -
implies a
reduced danger when being operated in dangerous areas with flammable or
explosive
gases or steams, such as chemical or petrochemical storing sites and places. A
flame-
less catalytic heating element can also be safely operated in areas with
highly flamma-
ble dust or metal dust and in building areas, where gas-powered vehicles are
being
maintained, stored or parked.
The catalyst portion may be part of the main catalyst. However, this is not
necessary.
The catalyst portion can be a separate unit for triggering of the reaction
which, then, is
transferred to the main catalyst. This makes the triggering portion
independent of the
main catalyst, which may be made of metal, for example platinum, palladium,
rho-
dium, ruthenium or iridium, and/or which may be made with a non-metallic
support,
for example activated alumina, silica, or ceramics.
In order to reduce the electrical power consumption during the triggering, it
is advan-
tageous if the metallic catalyst portion is substantially smaller than the
main catalyst.
For example, the metallic catalyst portion through which current flows has a
size of
less than 1 cm, preferably less than 1 mm. In a practical embodiment, the
metallic
catalyst portion is a metal mesh, and the size of that part of the mesh
through which
current is flowing for the triggering is between 0.1 mm and 0.5 mm, for
example
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around 0.25 mm. The term "size" covers any dimension, that is the length,
width and
height, of that part that is heated to the temperature at which the reaction
starts. For
example, in a practical embodiment, current is flowing through a mesh wire,
where the
mesh wire has a thinner catalyst portion than the rest of the mesh wire. The
thinner
catalyst portion is heated up to the triggering temperature of around 150 C
first and
starts the catalytic process when the mesh wire has contact with the oxygen in
the
oxygen enriched gas/air mixture which raises the temperature to a higher
temperature
level which is necessary for start of the process.
A preferred embodiment comprises a main catalyst being a metallic mesh,
because IR
radiation can traverse the openings in the mesh and leads to a better heat
distribution.
Such a mesh may be a thin mesh which is arranged in a flat configuration or
bent, for
example bent into a tube. For example, such a tube may be provided with a
cross sec-
tion that is circular, oval, or polygonal. The tube formed mesh has the
advantage that
IR radiation inside the tube easily escapes through the openings in the mesh,
which
allows for use of the tube formed catalyst to heat liquids in a tank
surrounding the
catalyst. As the catalyst does not need to surround a liquid tank but heats
the liquid
form an internal position with respect to the liquid tank, the catalyst heater
according
to the invention can be constructed compact, which is especially useful in
portable
devices.
In a further preferred embodiment, the main catalyst is a tubular mesh formed
with
varying cross section. In this case, it is an advantage to provide the gaseous
fuel to the
narrow part of the main catalyst. It has been observed in an experiment with a
catalyst
shaped as a truncated cone that a reduction of the supplied gaseous fuel
reduces the
catalytic burning to the narrow part of the truncated cone shaped catalyst,
where the
gas is supplied. If the supply of gaseous fuel is increased into the catalyst,
the catalytic
burning is distributed gradually also to the part with the larger cross
section. This
yields a smooth regulation mechanism for the desired heating efficiency.
A certain experiment used a conical catalyst in a cylindrical fluid-proof,
infra-red
transparent enclosure immersed in a liquid tank. The conical metallic mesh
catalyst
was provided with the large end towards a bottom of the enclosure and the
narrow end
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of the cone was arranged towards the gas exhaust. It was observed in this
experiment
that this arrangement yielded a higher efficiency for the catalytic burning
and heat
transfer than in an embodiment with a cylindrical catalyst in a cylindrical
enclosure.
The reason for this is not fully understood but believed to be due to a better
transport
5 of emission gases. Preferably, the gas itself is blown into the upper narrow
part of the
conical catalyst in the direction of the wide end of the cone.
In a further embodiment, the catalytic heating system comprises a venturi
system for
mix of fuel gas and oxygen before the catalytic burning. The venturi system
comprises
a venturi nozzle with a nozzle exit and a channel surrounding the venturi for
provision
of oxygen, for example provided in an air stream through the channel. The exit
of gas
from the venturi nozzle pulls air or oxygen along the gas stream in order to
provide a
blend of gas and oxygen or gas and air. A venturi system is robust and
dependable and
may be manufactured in a great number for low costs, which for a system is a
great
advantage because is considered to be distributed among many users.
In experiments, good results have been achieved, if the channel formed between
the
outer wall of the venturi nozzle and a pipe portion surrounding the nozzle is
provided
by an outer concave wall of the venturi nozzle and a convex pipe portion
around the
venturi to form a smoothly bending channel towards the venturi nozzle exit. By
this
means, a smooth flow of air was achieved resulting in a high efficiency of the
catalytic
burner.
The venturi system just described may also improve prior art systems without
the need
of the triggering catalytic portion. The advantage lies in the fact that a
high amount of
oxygen can be supplied to the fuel gas resulting in an efficient catalytic
burning. Ex-
periments have shown that the achieved efficiency with such a venturi can be
near
theoretical values. In other words, a catalytic heater with a catalyst and a
fuel gas sup-
ply may on a general basis take advantage of having a venturi system between
the gas
supply and the catalyst for mixing the fuel gas with oxygen from an oxygen
supply, for
example in the form of air. Especially advantage is the venturi system with
the con-
cave wall of the venturi nozzle and a convex pipe portion around the venturi
to form a
smoothly bending channel towards the venturi nozzle exit.
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Catalysis occurs in the temperature range 370-425 T. These temperatures
correspond
to IR wavelengths about 3-7 pm, which basically coinciding with the maximal
absorp-
tion spectrum of water, which is in the range of 3-7 pm. Consequently, IR
heating is
well suited for heating of water or water containing liquids. For embodiments
intended
to be immerged directly into the medium to be heated, there has to be provided
a wa-
ter-proof separation between the medium to be heated and the catalytic heating
ele-
ment. In order to enhance the efficiency of the transmission of the IR
radiation it is
advantageous to provide a partition wall made in a material that can be
optimised with
regard to both transmission of IR radiation and transfer of convection heat.
For exam-
ple, the partition wall may comprise aluminium, copper or quartz glass or a
combina-
tion of these.
A preferred portable embodiment of the invention has an integrated fuel tank.
This
fuel tank may be a refillable fuel tank or an exchangeable tank, for example
screwed
unto a corresponding winding and with a tube connection to the heater.
Optionally,
this fuel tank can be integrated in a handle or constitute a handle by itself.
In the case
of a portable system, the device may comprise a handle with a heating pipe
containing
the catalyst arranged in extension hereof. The heating pipe is produced in a
material
that is transparent for infra-red radiation and fluid-proof for immersion in
liquids.
When fuel gas is extracted from a fuel tank with liquid fuel, the evaporation
of the
liquid into a gas causes a temperature drop in the fuel tank near the exit of
the fuel
tank. This can lead to a limit for the rate at which gas can be extracted from
the gas
tank, especially if the surroundings, where the heater is used, are cold. In
order to
counteract this reduction of the extraction rate, there may be provided a heat
ex-
changer between the fuel tank and an exhaust pipe system for heat exchange
between
emission gas from the catalytic burning and a wall of the fuel tank. As the
emission
gas from the catalytic burner is hot, this heat energy can be used to heat the
tank. By
keeping the gas pressure and gas flow speed high, it is assured that a venturi
system
can work efficiently and add the necessary amount of oxygen/air for the
catalytic proc-
ess.
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For use in the military, the portable heating system has the advantage that it
is more
difficult to trace in use than conventional heating methods. The heating
system does
not have any form of visible flame. The system layout secures that the
portable heating
unit is surrounded by the medium, which has to be heated, which acts as a
shield for
the heat. Furthermore, the emission gas is cooled efficiently by transferring
heat to the
gas tank. Also, the air providing oxygen for the catalytic burning is heated
by the
emission gas. This has triple advantage: 1) the air intake gas is heated for
an efficient
catalytic burning, the gas tank is heated for gas extraction at a higher rate,
and the ex-
haust gas is cooled, which reduces the traceability of the system, which is
crucial in
military operations. Accordingly, there is only a weak thermal profile in use.
The con-
cept layout secures furthermore, that the sound level is very low and that no
smoke is
formed. Furthermore, the efficient burning from the onset without a flame
combustion
chamber as a start mechanism reduces smell from unburned fuel of the system to
a
minimum.
Due to the high efficiency, which is more than 3 times better than the off
grid heating
systems with cooking vessels and pots used today, this heating system is both
energy-
efficient and environmentally benign. The energy consumption is very low,
namely
only about 10-12 gram gas per litre water heated from 20 C to 100 T. By way of
ex-
ample, a propellant as natural gas, propane gas, butane gas, isobutene gas or
a mixture
hereof is being used. According to all prognoses, it should be possible to
supply bu-
tane gas for the next 100 years. Heating units may in practice also apply
hydrogen as
propellant without significant changes.
The heating system has proved to heat water to the boiling point reliably even
under
extreme weather conditions including very low temperature and strong winds.
There-
fore, it is suited for military purpose and extreme sport.
In another embodiment, the catalyst is elongate and extends horizontally or
substan-
tially horizontally in a bottom area of a liquid tank. For example, the
catalyst is tube
formed, as described above and arranged inside a water-tight and IR
transparent tube.
In order to direct the IR radiation in a certain direction, an IR mirror may
be provided.
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Alternatively, the catalyst is sheet formed and contained in a corresponding
water-tight
and IR transparent enclosure.
The invention is useful for a large number of uses, for example in the case of
a port-
able, off-grid heater system,
= Heating of water - scalable
= Heating of pools
= Heating of infusion fluids/intravenous fluids /blood
= Personal body heater
Sterilization of surgical instruments
= Heating of milk/food for babies
= Catalytic cooking plates - IR
= Portable oil radiators
= Central heating garments - extreme sporters, outdoor workers, rescue work-
ers, first responders,
= Off grid autoclave
= Heating of water in petrochemical environments
= Weed burner
and in the case of using the catalytic burner in connection with a gas
refrigerator prin-
ciple
= Cooling garments - extreme sporters, outdoor workers, rescue workers
= Cooling of fluids, for example water, infusion fluids, intravenous fluids,
or
blood
In the case of an on-grid application
= Heating of water - petrochemical areas/offshore/boats
= Heating of pools
= Portable oil radiators
= Water heaters and boiler for central heating
Catalytic LPG stoves
= Booster for heating of houses
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In connection with catalytic heaters, especially off grid portable systems are
challeng-
ing to construct, in as much as a long catalytic burning chamber requires a
large di-
ameter in order to be possible to ignite with a spark. For a certain length to
width ratio,
spark ignition, for example by a piezoelectric crystal, may be successful for
large sys-
tems, but fail for small systems. Experience from large systems with respect
to igni-
tion of the catalytic process seems not to be scalable to small systems. This
is surpris-
ing but has led to the ignition approach according to the invention.
A preferred embodiment is a flameless catalytic burner with a ratio between
the di-
ameter and the length is larger than 4. Further, it is preferred that the
burning chamber
is closed for immersion heating of liquid. especially in the case of a
portable off grid
device.
A preferred embodiment is a catalytic heater with a closed burning chamber for
im-
mersion into liquid and with a gas fuel supply through a venturi for adding
between
1% and 9% air which is optimum for catalytic burning. In a vertical
orientation of a
tube formed burner, exhaust gases will seek upwards and leave the heater
analogous to
exhaust gas in a chimney. If the chamber has a diameter of less than 38 mm,
and a
length of about 160 mm, which are suitable dimensions for portable systems, it
has
turned out that such a device cannot be ignited by a spark. Therefore, the
ignition sys-
tem with an electric heater being a catalyst itself is ideal for such a
system.
Preferable dimensions for portable systems are diameters of the burner of
between 10
and 50 mm, preferably between 30 and 40 mm, and lengths between 50 mm and 300
mm, preferably between 100 and 200 mm.
A prototype has been fabricated along these lines with a total weight of less
than 200
grams, an efficiency of more than 70% yielding an effect of 650 W, which is
the ap-
proximate heat capacity of a ceramic heating plate with a nominal effect of
1600 W.
The heat effect of a burner with an inner diameter of 22 mm and an outer
diameter of
24 mm, and a length of 130 mm was measured to 16.5 W/cm2. It was able to start
in a
temperature of -40 C without problems.
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As mentioned above, in order to provide fuel for a catalytic burner, a gas
supply is
inserted into the burner, such as a gas cartridge. Such cartridges are
commercially
available for example from the company Braun , which also commercially
supplies
curling irons. Such cartridges are supplied with an internal seat valve for
delivery of
gas from the cartridge, when a tube member of the seat valve is pressed into
the car-
tridge by a stem.
In order to provide an even flow of gas from cartridges, there are typically
provided
pressure valves in prior art apparatuses. Constant flow valves are described
in the prior
art patents documents mentioned above. In order to vary the flow for keeping a
con-
stant temperature, bimetallic valve elements may be applied. Such regulation
is neces-
sary, in as much as a seat valve in a cartridge according to the prior art
primarily works
as an on-off valve and is very difficult to adjust. However, these regulation
systems
are rather expensive solutions.
A better solution is given by a gas cartridge having a built-in gas flow
adjustment
mechanism that can be produced at low cost as described in the following. This
car-
tridge can be used as part of the invention described above but also can be
provided
independently thereof for other purposes, mainly catalytic burners, however.
The cartridge for gas with or without aerosols comprises a container for
containing the
gas and comprises a valve arrangement for release of gas from the container.
The
valve arrangement comprises a valve, for example seat valve, with a tube
member and
a resilient member providing a resilient force against the tube member in a
direction
away from the container. The tube member has an inner channel between a first
open-
ing directed towards the outside of the container and a second opening
directed to-
wards the inside of the container for release of gas from the container
through the
channel when the tube member is pressed against the resilient force a distance
along a
pressing direction towards the inside of the container.
Optionally, the tube member has a tube wall around the channel with a
plurality of
second openings interspaced along the pressing direction for release of gas
through a
selection of these openings in dependence of the distance by which the tube
member is
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pressed towards the inside of the container. For example, the second openings
have
mutually varying cross sectional sizes. Optionally, the tube wall is
cylindrical with the
first opening at the first end with an opposite closed end.
By varying the cross section and/or the number of the used openings for the
gas re-
lease, there is provided a simple stepwise adjustable valve into a cartridge.
Thus, it is
possible to time the gas flow - with or without aerosols - without the
necessity of hav-
ing a complicated valve arrangement in the apparatus, into which the cartridge
is in-
serted. As the apparatus into which the gas cartridge is inserted does not
need any
complicated or dedicated valve arrangement, any corresponding maintenance work
is
avoided for the user. If the valve is not function properly, the cartridge can
be ex-
changed with. another cartridge. As these cartridges are mass produced, the
costs are
low.
Preferably, the tube wall of the tube member is surrounded by a resilient
polymer gas-
ket, typically a sealing ring, which tightens the second openings against the
gas pres-
sure from the container. In practice, this may be achieved by locating the
openings on
that side of the gasket which is facing away form the container. When the tube
mem-
ber is pressed towards the container, one opening after the other is pushed to
the oppo-
site side of the gasket allowing gas to be released through these second
openings. In
the most preferred embodiment, all the openings that have been pushed to the
opposite
side of the gasket allow gas to flow into the openings.
Alternatively, the pushing of the tube member in the pressing direction may
open only
a selection of openings, possibly only one opening at a time, and close all
neighbour-
ing openings by second gasket means. The latter is relevant, if the openings
have dif-
ferent cross sections, for example, such that the first opening is used for a
first flow
rate and the next opening is used for a second, higher flow rate.
It is an option that the cartridge is a replacement cartridge, which is
replaced by an-
other cartridge when emptied and not filled with new gas on site. However, the
car-
tridge is advantageously part of a recycling system, where the cartridge is
refilled for
re-use at a recycling factory. As a step in this recycling procedure, the
cartridge is also
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tested for proper functioning of the valve arrangement, preferably a seat
valve. This
testing can easily be automated such that only minor costs arise for this
testing step in
the recycling process. It should be stressed at this point that the production
costs of a
cartridge is almost negligible as compared to commercially available prior art
car-
tridges.
For military use, it is of importance that the risk for explosion of a
cartridge for the
catalytic burner is minimised also with respect to the possibility of being
hit by a bul-
let. This minimising of the risk is achieved by providing the cartridge with a
low fric-
tion surface, for example a polytetrafluorethylene (PTFE, Teflon) surface. In
case that
the cartridge is hit by a bullet, the low surface friction minimises the heat
that is de-
veloped on the surface due to the bullet sliding along the surface during
deformation.
If the heat production due to the low friction is low, the gas may be
prevented from
ignition and explosion despite the fact that the bullet penetrates the
cartridge wall.
Cartridges used for gaseous fuel, such as for catalytic burners, may comprise
a tube
extending from the valve arrangement and into the middle of the container. If
the car-
tridge is filled with liquid gas only to less than the middle height of the
cartridge, liq-
uid gas cannot flow into the tube, not even when the cartridge is turned
upside down.
However, shaking of the apparatus with the cartridge during gas release may
cause
liquid gas to find its way into the tube, and proper gas release is disturbed.
As a coun-
termeasure, the cartridge in a further embodiment comprises a fibrous
absorptive ma-
terial for absorbing liquid gas. Optionally the fibrous material contains
cellulose based
fibres or cotton or both. Alternatively or in addition, polymer fibres may be
contained.
First experiments have used a simple, typical, commercially available prior
art tam-
pon, which has proved highly satisfactory for the gas absorption purpose.
Though not
strictly necessary, the fibrous absorptive material is advantageously combined
with a
cartridge-insert combination according to the above.
Typically, gas cartridges are provided with a screw thread for fastening of
the cartridge
to the apparatus of interest. Such screw threads are standardized and only
very few
variants are available due to the low number of mass producers. This implies
that an
apparatus using these cartridges has to be designed with one of these
standardized
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threads or with means for fastening of cartridges without threads at all.
These re-
quirements limit the degrees of freedom for the design of such an apparatus.
Thus, it would be desirable to have a greater variation of fastening means
such that
there is greater freedom with respect to apparatus design. In other words, it
would be
desirable to provide a solution for a gas cartridge for having greater variety
of screw
connections. This is achieved with an insert for a gas cartridge, the gas
cartridge hav-
ing a valve arrangement for release of gas with or without aerosols from the
cartridge.
The cartridge has first fastening means and the insert has second fastening
means con-
figured for cooperation with the first fastening means for fastening the
insert to the
cartridge around the valve arrangement. The insert has a screw thread for
screw con-
nection with a gas consuming apparatus.
By such an insert, gas cartridges can be provided with screw threads adapted
to the
apparatus of interest. For example, such an insert may be used in connection
with the
cartridges having a stepwise adjustment mechanism as described above, however,
it
may also be used any other kinds of suitably dimensioned cartridges, for
example for
prior art standard cartridges without stepwise regulation.
By selecting a screw thread dimension which is different from prior art
commercially
available threads, it is prevented that the cartridge is used for other
apparatus than de-
signed with a corresponding thread. In turn, if an apparatus is provided with
a certain
thread, only those cartridges can be used that have a corresponding thread in
the insert.
Thus, the manufacturer of a specific apparatus needing a certain type of gas
or
gas+aerosol mixture may order a number of cartridges with the desired content,
and
may provide these with inserts of a kind that only matches the special thread
of the
specific apparatus. Thus, the cartridge itself may become a new production
standard,
whereas the insert may be selected in dependence of the desired content and/or
in de-
pendence of the manufacturer or specific apparatus. This implies that a fuel
gas car-
fridge may be provided with a different thread in the insert, for example a
larger
thread, than an aerosol cartridge, by which no accidental and possibly risky
mismatch
between the apparatus in question and the corresponding cartridge occurs.
Thus, the
system with the insert has a potential for a pronounced increase in safety for
the user.
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The cartridge may be produced with a cavity around the valve arrangement, the
cavity
having a side wall widening in an inward direction of the cavity so as to form
a shoul-
der in the cavity. For example, such a shoulder is formed during a press-
mounting of a
closure member with the valve arrangement onto the rim of a container, where
the side
walls of the closure member are deformed. Thus, no special production action
is re-
quired for producing these shoulders, because commercial cartridges are
already pro-
vided with such a circular shoulder along the rim of the cavity. Thus, such a
cartridge
can relatively easy be included in today's production processes. Typically,
the insert
would have an overall cross section similar to the cavity. In a preferred
embodiment,
the insert has resilient wings for fastening the insert to the cartridge by a
clip action of
the wings under the shoulder.
Commercially available cartridges have a seat valve with a tube member from
which
gas can be extracted when the tube member is pushed partly into the container.
In or-
der to protect such tube members, the insert may have a central protection cap
for cov-
ering a gas exit of the valve arrangement.
Preferably, the insert has a substantially circular cross section with a rim
part compris-
ing the wings and the screw threads, which preferably are directed inwards.
Advanta-
geously, the protection cap is connected to the rim part by a plurality of
bars config-
ured for manual breaking to release the cap from the rim part. These bars
imply a
safety signal for the user, because the cartridge can only be used without the
cap, and a
breakage of the bars for removal of the cap clearly indicates for a user that
the car-
tridge has been used before.
When the insert is inserted into the cavity of the cartridge, and the
cartridge with the
insert threads is screwed onto a cooperating thread of an apparatus, screwing
of the
cartridge relatively to the apparatus moves the cartridge towards or away from
the ap-
paratus. If the apparatus is equipped with a static counterpart pushing
against the tube
member, the turning also moves the tube member in or out of the cartridge for
adjust-
ment of the flow.
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As has turned out during experiments, a threading of 0.5 - 1.0 mm implies a
good
modulation and touch with the flow adjustment.
The cartridge is especially suited for a heating apparatus with a catalytic
burner. For
example, the heating apparatus has an enclosure for enclosing the cartridge.
When the
cartridge is emptied to run the catalytic burner, the shift of the fuel from
the liquid
phase to the gas phase may lower the temperature of the cartridge. In
addition, also
cold environments may result in a low temperature of the cartridge such that a
proper
flow out of the cartridge is no longer guaranteed. In order to improve this
situation, the
heating apparatus may have a flow path leading the burned gas from the
catalyst past
the cartridge, thereby providing a heat exchanger arrangement in the enclosure
around
the cartridge for heat exchange between burned gas from the catalytic burner
and the
cartridge surface. This reduces also the temperature of the exhaust gas, which
may be
a great advantage to reduce the thermal (infrared) traceability of the heater
in military
operations.
For reducing this traceability further, in another embodiment, the enclosure
also
houses a flow path for the intake air for the catalytic burner, the enclosure
comprising
a heat exchanger for heat exchange between the hot, burned gas from the
catalyst and
the intake air for the catalyst. Thus, the emission gas is cooled from the hot
state im-
mediately after the catalytic burning at more than 400 C to a cool state only
slightly
above ambient temperature.
For reducing this traceability even further, the envelope may have gas release
openings
for release of burned gas to the surrounding atmosphere after heat transfer
from the
gas to the surface of the cartridge, where the release openings have radially
outwards
directed flow paths. The term radially outwards has to be understood
relatively to a
cartridge having a cylindrical shape. Experimentally, it has been verified
that the mix-
ing with surrounding air is more efficient when the flow is radial as compared
to a
flow, where the emission gas is directed parallel with the cylindrical surface
of a car-
tridge.
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Such a catalytic heater is especially useful for military application, pre-
hospital envi-
ronments, and field hospitals, for use during hiking, trekking or camping, for
heating
of water or food, and for use as a warmer for parts of the body. The use for a
curling
iron is also possible among a large variety of other applications.
A preferred embodiment for catalytic burners, as already described above,
comprises a
catalyst being a metallic mesh, because IR radiation can traverse the openings
in the
mesh and leads to a better heat distribution. Such a mesh may be a thin mesh
which is
arranged in a flat configuration or bent, for example bent into a tube.
SHORT DESCRIPTION OF THE DRAWINGS
The invention will be explained in more detail with reference to the drawing,
where
FIG. 1 show a sketch of a portable heating system according to the invention,
FIG. 2 illustrates a portable system in more detail,
FIG. 3 illustrates a heating unit in a bottle, a) covered with a lid and b)
with a fuel tank
installed
FIG. 4 illustrates a portable pressurized sterilizer a) closed with a lid and
b) with a
heating unit inserted,
FIG. 5 illustrates a catalyst with plane straight units in a) end view and b)
side view,
FIG. 6 illustrates a catalyst with plane straight or plane bent units, wherein
a) shows a
straight unit, and b), c), and d) show different bent units, and e) is a
straight double
catalyst,
FIG. 7 illustrates an embodiment with a conical catalyst mesh,
FIG. 8 illustrates an embodiment for a warm water supply with a conical mesh
cata-
lyst,
FIG. 9 illustrates a portable flexible liquid heater bag,
FIG. 10 shows a portable infusion heater,
FIG. 11 illustrates a body heater,
FIG. 12 shows an embodiment for a triggering system in a heater system and
with a
venturi system for a heating system according to the invention,
FIG. 13 shows a gas cartridge in a side view a) before insertion of an insert,
and b)
after insertion of the insert;
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FIG. 14 shows the cartridge in a transparent view a) before and b) after
insertion of the
valve cup;
FIG. 15 shows the valve cup in greater detail;
FIG. 16 shows the cup insert in a) a cross sectional side view, b) in an end
view with
the protection cap, and c) in an end view with removed protection cap;
FIG. 17 shows the valve cup with inserted cup insert and adapter;
FIG. 18 shows an assembly sequence a) before and b) after insertion of the
valve cup
into an adsorptive media, c) before and d) after insertion of the adsorptive
media with
the valve cup into the container, and e) in an end view;
FIG. 19 shows the cartridge inserted into an apparatus in a) cross sectional
side view
and b) in an enlarged partial view;
FIG. 20 shows an alternative embodiment with a tube around the cartridge in
the appa-
ratus in a) an overview and b) partially stripped enlarged view;
FIG. 21 illustrates a heater with passive flow adjustment,
FIG. 22 illustrates a heating system for the cartridge.
DETAILED DESCRIPTION / PREFERRED EMBODIMENT
FIG. 1 shows a heating system 1 according to the invention. The heating system
1
comprises a heating unit 2 and a protecting container 163. The heating unit 2
has a
handle 4 for attachment of the heating unit 2 and a heating pipe 5 that emits
heat radia-
tion from the catalytic element contained in the heating pipe 5. The heating
pipe 5 can
be fitted into a protective container 163, when the heating system is not in
use. The
container 163 may also be used for storing fluids or other materials such as
powder,
for example in connection with heating with the heating pipe 5 or in order to
constitute
a storage container of fluid or other materials during transport and use. The
container
163 may be used for hot fluids and function as a thermo-isolating bottle or
for warn-
ing hands by holding the container 163. The container 163 may be thermally
isolated
in order to reduce the output of energy to the surroundings.
The container 163 has an upper opening 6 and a thread 7 corresponding to an
internal
thread (not shown) of an adapter 8 in one end of the handle 4. FIG. 1 a shows
the heat-
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ing unit 2 and the container 163 separated from each other, while FIG. lb
shows the
heating unit 2 and the container 163 in a situation, in which they are screwed
together.
It should be noted that the container 163 may have other shapes and sizes than
the one
shown in FIG. 1, and the heating system 1 may be provided with a number of
other
containers for heating of fluids or other materials. It would be beneficial to
provide
such other containers with an internal or external thread 7 in their open end
6, so that
they may be screwed together with the adapter 8 for heating of the material
therein. In
connection to heating of fluid or another material in the container 163, it is
up to the
user to take into account any pressure rise in the closed tank that could
occur during
the heating. In order to prevent damage to the material and/or the personnel
in case of
over-pressure in the container 163 due to the heating, the heating system 1
may ad-
vantageously be provided with a safety valve connected to the interior of the
container
163, in order to provide a passage for equalization of pressure relative to
the atmos-
phere in case of over-pressure in the container 163. It is not necessary that
a fluid-
filled tank is screwed together with the adapter 8 during the heating process.
The heating system 1 may, near the handle 4, furthermore, be provided with a
pivotal
hanger 9 for attachment of the system 1, for example in a belt on a uniform.
The heating pipe 5 is closed at the lower end in order to prevent fluid from
entering
the pipe 5. Accordingly, there is no entry of fluid from the container 163
into the han-
dle 4 or into the pipe 5. The safety valve for equalization of pressure may
also be lo-
cated in the adapter 8.
In the pipe 5, there is installed a catalytic burner in the form of a metallic
mesh that is
supplied with gas to the process from a fuel/gas tank in the handle 4. Between
the gas
tank and the catalytic burner in the pipe 5 there is provided a valve, which
can be con-
trolled by use of a regulator via a button 11 or a build in valve in the fuel
tank. In order
to make the catalytic process start, it is necessary to heat the catalyst.
This can be done
by pushing a push button 10 as shown in FIG. lb. The push button 10 both
provides
electricity to the catalyst portion that ignites the flameless catalytic
burning and opens
for the gas so that the heating unit 2 may be operated with one hand. Air
suction and
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19
exhaust of gas is provided via openings in the upper part of the handle, in
which there
in FIG. la and lb is shown the air suction opening 12, while the exhaust
opening on
the opposite side of the handle is not shown in this figure. Such suction
openings 12
and exhaust openings may be provided with a regulation valve 13 for regulation
of the
volume of intake air and emission gas, respectively, through the openings.
In FIG. 2 is shown a specific embodiment of the more general heating system 1
shown
in FIG. 1. The sketch in FIG. 2 shows the handle 4 with the heating pipe 5
inserted
into the built-on container 163. The handle 4 comprises a fuel/gas tank 14,
from which
gas via a regulator 15, for example operated by a button 11 as shown in FIG.
1a, is fed
into a nozzle 16. Such nozzle 16 is part of a venturi system 17, so that the
gas carries
air and hence oxygen along with it, when the gas is feed out of the tank 14.
This air is
provided via the pipeline 18 that is connected to the inlet port 12. The gas
and air mix-
ture is feed through a transport pipe 19 between the venturi system 17 and a
catalytic
element 20. The transport pipe 19 is on the same level as the catalytic burner
20,
which may be provided with apertures or an adjusted length in interaction with
a spe-
cial shaped bottom that forms the closing section of the catalytic element 21
in order
to ensure a smooth flow and gas-air distribution in the catalytic burner 20.
After the
catalytic process, in which the fuel gas is converted to carbon monoxide and
water
vapour, these emission gases are feed through another pipe system 22 to an
exhaust
opening 23 in the opposite section of the handle 4.
The catalytic burner 20 can have different geometrical shapes depending on the
in-
tended application and efficiency. As an example, it may comprise or be
comprised of
two plane units or of one or more curved units, for instance cylindrical
units, which is
illustrated in more detail in FIG. 5 and 6. FIG. 5a and 5b illustrate end view
and side
view of a heater system 30 inside which a plane straight catalyst 31 arranged
in a liq-
uid tight enclosure with flat enclosure walls 32 and 33 through which IR
radiation is
emitted to both sides. The system has an air inlet 34 and a gas exhaust 35. In
order to
provide an even flow of inlet gas/air mixture, there is provided a manifold
with multi-
ple inlets 36 in the lower part 37 of the heater system.
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Alternatives for plane catalysts are illustrated in FIG. 6. FIG. 6a is a
sketch of the
plane straight catalyst 31 with air inlet 34 and gas exhaust 35. FIG. 6b
illustrates a
plane curved catalyst 38 forming a bending of a half circle, whereas FIG. 6c
and 6d
illustrate plane catalysts 39, 40, 41 with a bending over larger angles. A
double
straight plane catalyst 42 with is illustrated in FIG. 6e.
With reference to FIG. 1 and 2, the catalytic process produces a great amount
of infra-
red radiation, which is being transmitted through the material of the heating
pipe 5 and
into the container 163, which is closed upwardly with a partition wall 29. The
medium
in the container 163 is being exposed to the infra-red radiation that
especially heats the
water in the container 163. In order to ensure an effective utilization of the
infra-red
radiation, the container 163 may be provided with a reflective coating on the
inside, in
order to reduce the emission of heat through the wall of the container 163. It
is fur-
thermore possible to construct the container 163 with a general heat
insulating wall,
optionally with a multi-layered structuring as known from thermo-isolating
bottles and
cans.
With a heat insulating container 163 and a handle that is not heated, it is
difficult to
trace the use of such heating system 1 in relation to military actions,
because the
emission of heat, by this way, is minimised. A certain kind of emission of
heat imply-
ing a potential risk for tracing during application is associated to the
heated emissions
(gas, water vapour) from the known catalytic process through the exhaust
opening 23.
To reduce the temperature of the emission gases, there is provided a counter
flow heat
exchanger 25 that, at least in part, encloses the gas tank 14 in order to
transform heat
from the exhaust emissions to the walls of the gas tank and further to the gas
exit of
the gas tank and to the liquid gas inside the gas tank 14. Moreover, the
pipeline 22 for
the emission gas is, at least in part, surrounded by the pipeline 18 for the
intake air
through the inlet port 12. Accordingly, heat is transferred from the emission
gases to
the gas tank 14 and to the intake air, which contributes towards an optimal
catalytic
combustion. In this connection it should be mentioned that the gas from the
gas tank
14 during expansion after the nozzle 16 in the venturi system 17 entails a
cooling of
the gas which increases the uptake of heat from the emission gas. Emission of
heat
from the emission gas to the intake gas and the gas tank 14 contributes
towards to en-
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21
sure an expedient function of the heating system 1 also in very cool
surroundings.
Therefore, the heating system 1 is well suited for use both in hot and cool
areas, and
due to its robust nature, it is well suited for use in the military sector.
In the case of heating of water, food or another medium 24 in the container
163, when
it is mounted on the adapter 8, a possibly generated over-pressure in the
container 163
due to the heating induces a risk for the heating system 1 and for the user of
it. In order
to reduce the risk for damage of the apparatus and the personnel, the heating
unit 1 is
provided with a safety valve 25 between to the interior of the container 163
and the
atmosphere outside the tank. The safety valve opens a passage between the
interior of
the container 163 and the surrounding atmosphere for equalization of pressure.
The
over-pressure valve is in the figure located in the adapter 8, but it is
possible to pro-
vide a over-pressure valve in other appropriate places in the apparatus.
To be even easier to operate, the heating unit 2 may, furthermore, be provided
with a
heat sensor 26, which by use of the infra-red radiation emitted by the medium
24 can
measure the temperature of the medium 24. Alternatively, such heat sensor 26
may
comprise a thermometer that measures the temperature of the medium while being
submerged into the medium. However, this embodiment is not shown in FIG. 2.
The
heat sensor may be connected to a temperature indicator on the handle (not
shown) or
to an acoustic device that indicates when the medium 24 has reached a certain
.preset
temperature. It may, as an example, be possible to set this temperature on a
unit on the
handle or the temperature may be preset, so that it is indicated when a
certain tempera-
ture is reached, for instance by a sound or light indication on the handle.
Hence, it may
also be considered to use installed light indicators in different colours or a
number of
light indicators that are turned on depending on the temperature reached in
order to
indicate to the user the temperature reached or exceeded.
As a further alternative, a temperature dependent valve that regulates the gas
flow di-
rectly to the catalytic burner may be inserted. If the temperature in the
catalytic burner
exceeds a preset temperature, this temperature dependent valve will regulate
the gas
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flow downwards until the temperature come down below the level that is
permitted in
the catalytic burner.
FIG. 3b shows a bottle 95 with an inserted heating unit 2 having a fuel tank
14 and a
heating pipe 5. An overpressure valve 92 prevents damage due to overpressure
in
analogy with the above mentioned embodiments. When the heating unit 2 is not
in
use, the fuel tank 14 may be removed and the remaining heating unit with the
heating
pipe 5 covered by a lid 89, as illustrated in FIG. 3a. The heating unit is
connected to
the bottle 95 by a standard adapter 8 as mentioned in connection with the
other em-
bodiments.
FIG. 4a and b illustrate a portable pressurized sterilizer 96 with a
pressurisable con-
tainer 97 closed with a pressure resistant lid 98, which is opened to insert
medical
tools or other effects to be sterilised. Optionally, these tools may be placed
into a grid
which is inserted into the container. When not in use, as illustrated in FIG.
4a, the con-
tainer 97 is closes by another lid 89. This other lid 89 is removed, when a
heating unit
2 is inserted into the container 97, which is illustrated in FIG. 4b.
Alternatively, the
heating pipe 5 may reside inside the sterilizer, and only the fuel tank 14 is
removed for
placing the another lid 89.In order for the sterilizer not to explode, the
heating unit 2 is
provided with a pressure valve 92. This overpressure for the valve to open may
be
adjusted to a predetermined value, for example 2 bars.
In fact, a portable pressurised sterilizer is generally useful when combined
with cata-
lytic burners, also if the burners have other ignition systems than the
present invention.
For example, a piezoelectric ignition system or a system as disclosed in US
4,886,017
by Viani could be used alternatively. Thus, useful is a portable pressurised
sterilizer
with a pressurizable container having an opening for insertion of elements to
be steril-
ized and with a catalytic burner immersed in a liquid inside the container.
Preferably,
the catalytic burner has a heating pipe containing the catalyst, where the
heating pipe
is produced in a material that is transparent for infra-red radiation and
fluid-proof for
immersion in liquids. Such a catalytic heater may be fastened to an opening in
the con-
tainer for submersing the heating pipe into the liquid in the container, where
the open-
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23
ing cooperates with an adapter of the catalytic burner in order to achieve a
tight fasten-
ing, for example a screw fastening.
FIG. 7 illustrates an embodiment with a conical catalyst. This embodiment
comprises
a conical main catalyst 50 connected to a gas supply tube 51 at the narrow end
of the
cone for release of fuel gas and air mixture in the upper end of the conical
main cata-
lyst 50. The gas is released under pressure, which transports the gas to the
lower, wide
end of the cone, where also a trigger mechanism with a catalyst portion 52 is
located.
Gas is supplied through a gas inlet 53 via a gas flow regulator 54 and a
venturi system
55, where gas and air from the air inlet 73 is mixed. For the triggering, the
flow regu-
lator opens for gas/air supply into the lower end of the main catalyst tube 50
and
switches electrical current in wire 56, which is electrically connected to the
catalyst
portion 52. The metal catalyst portion 52 in the bottom part of the main
catalyst tube
50 is electrically heated by electric conduction through the metallic catalyst
portion 52
acting as an electrical resistant heater up to a temperature high enough, for
example
between 150 C and 250 C with additional temperature increase due to the
provided
oxygen, to start catalytic reaction, which occurs typically between 300 C and
500 C.
The catalytic reaction triggers the catalytic burning inside the main catalyst
50. The
emission gas 57 is extracted through a gas exhaust 58.
The catalytic burning inside the conical main catalyst 50 emits IR radiation
through
the IR transparent enclosure 59, for example made of quarts glass or
aluminium, out-
side of which water is flowing within a water tube 60, the water being
provided
through water inlet 61 and released through water outlet 62. Alternatively,
the water
may be substituted by other liquids in connection with the embodiment. As the
water
absorbs the IR radiation efficiently, the wall 64 of the water tube may be
made of a
light weight material, such as plastic. However, other materials are possible,
for ex-
ample steel or other metals. Preferred is a material which is opaque to IR
radiation.
The conical metal mesh of the main catalyst 50 has proven to yield a proper
transport
of emission gases better than a cylindrical tube. As the emission gases are
hot, they
transfer heat to the water also in the part above the catalyst 50. In order to
provide as
much heat as possible to the water in the water tube 60, the gas supply tube
51 is pro-
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vided with a ceramic part 63, thermally isolating coating or surrounding
ceramic tube,
on the part above the catalyst, and, optionally, also inside the catalyst.
The electrical wire is connected to the catalyst portion 52 through the water
tube 60 by
way of tight flanges 66. The gas flow regulator is electrically connected 67
to a tem-
perature sensor 68 for measuring the actual temperature of the water in the
water tube
60. In addition, the flow regulator 54 is connected 71 to the venturi system
55 and
connected 70 to a lambda sensor 69 for adapting the burner to optimal
catalysis for
highest efficiency and reduced environmental load.
The portable embodiment of the invention is especially suitable for hikers and
for
military purposes
In FIG. 8, a conical catalyst 50 is illustrated in an embodiment, where the
catalyst 50 is
embedded in a liquid tank 60 for a non-portable application, for example for
water
distribution grid application, as an industrial liquid warmer, or as a
household water
heater. The reference numbers are as in FIG. 5 for likewise elements. The
arrangement
is different from the apparatus in FIG. 5 in that the catalyst is provided in
a horizontal
orientation in the bottom of the liquid tank 60, where the temperature,
normally under
heating conditions is substantially lower than at the top, where the heated
liquid is
extracted through liquid outlet 62. For example, the temperature profile of
the liquid
may be approximately linearly increasing with height from the catalytic
burner. Thus,
a typical temperature range between the bottom and the top of the liquid tank
is from
C at the bottom due to the cold inlet liquid with a temperature of around 15
C and
25 to around 80 C at the top, where liquid is extracted. In order to direct
the IR radiation
efficiently into the liquid tank 60, there is provided a reflector 72 below
the IR trans-
parent enclosure 59.
FIG. 9 shows a portable liquid heating bag 75, in a perspective view in FIG.
9a, illus-
trating a heating system 74 comprising a heating unit 2 with a heating pipe
inside a
flexible bag 75 the volume 91 of which filled with liquid, typically water.
For exam-
ple, the heating bag 75 may be used for melting snow added into the volume 91
through opening 90 in order to get water for consumption. The view in FIG. 9b
shows
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a cross sectional cut through the flexible bag 75 such that an arrangement
with a heat-
ing pipe surrounded by an outer tube 76 is visible. The outer tube 76 has
lower open-
ings 77 and upper openings 78 such that water or other liquid can flow into an
inter-
space between the heating pipe and the outer tube 76. The heating of the water
in this
5 interspace creates convection of the water or other liquid in the interspace
such that an
efficient circulation is created from the lower openings 77 to the upper
openings 78.
The liquid in the volume 91 may be used for heating other material. For
example, as
illustrated in FIG. 10a and 10b, a likewise system is illustrated, where a
liquid box 79
10 is inserted into the heating bag 75 for heating by the water or liquid in
the enclosure
75. This liquid box may contain an infusion liquid or blood for medical use or
other
material. The enclosure 75 can be equipped with an upper folding closure 80
which
can be unfolded for access to the inner volume of the enclosure. Through this
folding
closure, the liquid box 79 may be inserted or removed from the enclosure 75.
Other
15 closing mechanisms, for example a zip closure, may be used alternatively.
In fact, the liquid heating bag is generally useful when combined with
catalytic burn-
ers, also if the burners have other ignition systems than the present
invention. For ex-
ample, a piezoelectric ignition system or a system as disclosed in US
4,886,017 by
20 Viani could be used alternatively. Thus, useful is a portable liquid
heating bag made in
a flexible material and having an opening for insertion of a catalytic burner
immersed
in a liquid inside the container. Preferably, the catalytic burner has a
heating pipe con-
taining the catalyst, where the heating pipe is produced in a material that is
transparent
for infra-red radiation and fluid-proof for immersion in liquids. Such a
catalytic heater
25 may be fastened to an opening in the bag for submersing the heating pipe
into the liq-
uid in the bag, where the opening cooperates with an adapter of the catalytic
burner in
order to achieve a tight fastening, for example a screw fastening. Preferably,
the heat-
ing pipe 5 is surrounded by an outer tube 76 with lower openings 77 and upper
open-
ings 78 such that water or other liquid can flow into an interspace between
the heating
pipe 5 and the outer tube 76. The heating of the water in this interspace
creates con-
vection of the water or other liquid in the interspace such that an efficient
circulation
is created from the lower openings 77 to the upper openings 78. The latter
ebbodiment
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is also useful in connection with the sterilizer as describe above and with
the body
heater as described below.
In FIG. 11 a, a body heater 81 is illustrated with a tube system 82 to be
placed onto the
body surface, for example along arms and legs inside clothing. The tube system
is
connected by circulation tubes 83, 84 to a heat container 85 inside which a
heating
system 2 according to the invention is arranged. FIG. 1 lb shows the heat
container 85
in greater detail. A fuel tank 14 provides the necessary fuel for the heating
unit 2
which warms up liquid inside the heat container 85. By a pump system 86,
heated liq-
uid enters end exits the heat container through respective openings 87a, 87b.
Option-
ally, the pump system may comprise a pump speed regulator 88. When the body
heater
81 is not in use, the heat container 85 may be closed by a lid 89 after
removal of the
heating unit 2 or after removal of the fuel tank 14, which is illustrated in
FIG. 11c. An
overpressure valve 93 is provided in order to prevent explosion in case that
the liquid
is heated over the boiling point.
In fact, the body heater is generally useful when combined with catalytic
burners, also
if the burners have other ignition systems than the present invention. For
example, a
piezoelectric ignition system or a system as disclosed in US 4,886,017 by
Viani could
be used alternatively. Thus, useful is a portable body heater having an
opening for
insertion of a catalytic burner immersed in a liquid inside the container.
Preferably, the
catalytic burner has a heating pipe containing the catalyst, where the heating
pipe is
produced in a material that is transparent for infra-red radiation and fluid-
proof for
immersion in liquids. Such a catalytic heater may be fastened to an opening in
the bag
for submersing the heating pipe into the liquid in the bag, where the opening
cooper-
ates with an adapter of the catalytic burner in order to achieve a tight
fastening, for
example a screw fastening.
FIG. 12 shows a venturi system and a triggering system for a heating system
according
to the invention. It should be noticed that the venturi system is not
necessary for the
triggering system to function and the triggering system is not necessary for
the advan-
tages of the venturi. However, a combination is preferred due to the optimised
per-
formance.
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27
As illustrated in FIG. 12, a venturi system 55 is provided for mix of fuel gas
42 and
oxygen/air 43. The fuel is provided as evaporated fuel gas 42 through a
venturi nozzle
44 and the oxygen/air is added through a channel 45 smoothly bending towards
the
nozzle exit 49, the channel being provided as the space between the concave
outer side
46 of the nozzle 44 and the convex inner wall 47 of the surrounding pipe
portion 48.
The heating pipe 5 encloses a ceramic connection 63 between the venturi 44, 48
and
the fastening means 94 of the conical main catalyst mesh 50.
An electrode 99 is isolated 100 against a conducting base 101, which is
electrically
connected to a holder 102. The holder 102 is electrically connected to the
electrode 99
via a catalyst part 104 which is heated by current flowing from the electrode
99
through the catalyst part 104 to the base 101. As the gas mixture is provided
at the
upper end of the catalyst mesh 50, the gas has to be transported 104 to the
lower, wide
part of the catalyst mesh 50. At the lower end, the gas has to change
direction which is
achieved with very low flow resistance by a curved surface 105, preferably a
spheri-
cally curved surface. After being burned, the emission gas 57 leaves the
burner be-
tween the mesh 50 and the outer pipe 5. Relative to the main catalyst 50, the
surface
area of the catalyst part 104 is very small, such that only a small current is
necessary to
heat the catalyst part 104.
In FIG. 13a, a gas cartridge 14 is shown. In comprises a container 162 closed
by a
valve cup 163, from which a tube member 164 extends for release of gas from
the con-
tainer 162. As will be more obvious from the following, especially FIG: 14a,
the valve
cup 163 has a cavity 166, into which a cup insert 165 can be inserted. The
upper im-
age, FIG. 13a, shows the cup insert 165 outside the valve cup 163, and the
lower im-
age, FIG. 13b, shows the cup insert 165 positioned inside the valve cup 163.
The cup
insert 165 comprises a protection cap 106 covering the tube member 164 for
protec-
tion of it. Fastening of the protection cap 106 inside the cavity 166 of the
valve cup
163 is achieved by a number of resilient wings 107, which in illustrated in
greater de-
tail in FIG. 16a-c.
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28
FIG. 14a shows the cartridge 14 before insertion of the cup insert 165 and
FIG. 14b
shows the cartridge 14 after insertion of the cup insert 165. The cartridge 14
comprises
the container 162 with a container wall 108, inside which an absorptive media
109 is
located which absorbs liquid gas. When gas is released from the cartridge 14
through
tube member 164 the drop in pressure leads to a further evaporation of gas
from the
liquid gas in the absorptive media 109. The gas travels along tube 110 into
valve 111
and is released through tube member 4.
It should be mentioned that first experiments have revealed that fibrous
material in the
form of commercially available prior art tampons have proved efficient liquid
gas ab-
sorbers. These are efficient to a degree that proper upside down functioning
of the
cartridge is guaranteed despite the fact that the tube 110 can extend farther
than half
way down into the gas container and the amount of liquid gas in the container
fills
more than half the volume of the container.
FIG. 15 shows the valve 111 in the valve cup 163 in greater detail. The tube
member
164 has a tube wall 112 and an internal channel 113 through which gas is
released
through opening 113' at tube end 112'. The release of gas is achieved, when
the tube
member 164 is pressed into the space 114 by counteracting the resilient force
from the
spring 127 (or, alternatively another type of resilient member). The spring
127 presses
the tube member shoulders 115 against rubber sealing 116 in a seat valve
configura-
tion. This rubber sealing 116 closes for gas access to the three release
channels 117a,
117b, 117c. Gas finds its way into space 114 through tube 110 and pipe 118.
The tube
member 164 may be pressed a distance into the space 114 such that only the
first re-
lease channel 117a is open for gas release from the space 114. This leads to
gas release
at a first release rate. If the tube is pressed further into the space, gas is
released
through the first release channel 117a and through the second release channel
117b,
leading to a faster release rate of the gas. An even further pressing of the
tube member
into the space 114 leads to a release not only through the first 117a and
second 117b
release channel but also through the third release channel 117c, implying an
even
faster release of gas through internal channel 113 of tube member 4. The cross
sec-
tional size of the release channels 117a, 117b, 117c may be equal or may be
varying.
In addition, the number of release channels can be different from three in
dependence
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29
on the desired number of release steps. The seat valve 111 is gas-tightly
supported and
enclosed by a metal surrounding 119 and support cone 120 being part of the
valve cup
163.
The valve cup 163 has an open ring 121 with a sealing 122 for engagement with
the
neck 123 of container 162 as illustrated in FIG. 14a. During production, when
the
valve cup 163 is mounted on the container neck 123, the initially straight
side walls
124 of the valve cup 163, as shown in FIG. 15, are deformed into shoulders
126, as
shown in FIG. 14a, for secure and gas tight fastening of the valve cup 163 to
the con-
tainer neck 123. These shoulders 126 are used for holding the cup insert 165
in place,
as the resilient wings 107 during insertion slide along the inner side 125 of
the open
ring 121 and grab into the shoulders 126, which is illustrated in FIG. 14b.
FIG. 16a is a side projection of the cup insert 165 in analogy to FIG. 13a,
and FIG. 16b
is a top view before removal of the protection cap 106. The protection cap 106
has a
lower rim 106', which is not shown in FIG. 16a. The lower rim 106' is
connected to
the outer ring 128 by bars 129 which are broken for removal of the protection
cap 106,
after which the cup insert 165 appears as illustrated in FIG. 16c.
The cup insert 165 also comprises inner threads 130 for connection to a gas
consum-
ing apparatus, for example via an adapter 131, as illustrated in FIG. 17. The
adapter
131 has a first threaded part 132 engaging with the threads 130 and a second
part 133
with outer threads 134 for engagement with cooperating threads in an
apparatus. Such
an engagement will be explained in more detail later.
FIG. 18a-18e illustrates an assembly sequence for a cartridge according to the
inven-
tion. In FIG. 18a, the valve cup 163 with the tube 110 is provided with a
sleeve 135 of
an absorptive media 109. The sleeve 135 has an inner tubular channel 136 for
accom-
modation of the tube 110 and with a conical part 138 at the one end 137 for
facilitating
the insertion of the tube 110. FIG. 1 8b shows the situation when the tube 110
is ac-
commodated in the sleeve 135. The assembly of the valve cup 163 and the sleeve
135
is inserted into the container 162, as illustrated in FIG. 18c, and then
sealed by defor-
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mation of the straight walls 124 into shoulders 126, which is shown in FIG.
18d. FIG.
18e shows an end view of the final assembly.
The absorptive media 169 takes up liquid gas and prevents that liquid gas
enters the
5 tube 110 such that only evaporated gas is released through tube member 164.
The ab-
sorptive media 109 can be made of various kinds, however, first prototypes
used tam-
pons without superabsorbants. Tampons of the normal commercial type have
proven
to be suitable for absorbing all liquid gas efficiently. During filling of
liquid gas into
the container 162, the tampon absorbs the liquid and expands, until it fills
most of the
10 container, as illustrated in FIG. 2b.
It should be mentioned that the primary purpose of the invention is in
connection with
fuel cartridges. However, aerosol gas cartridges is another application. If
aerosols are
desired, the tube 110 may extend even further into the container 162.
FIG. 19a illustrates a possible embodiment of an apparatus in the form of a
catalytic
burner containing a cartridge 14. FIG. 19b is an enlarged view of part of FIG.
19a. The
outer threads 134 of the adapter 133 are engaged with inner threads 140 of the
appara-
tus 1 for mount of the cartridge 14 onto the apparatus 1. The tube member 164
extends
through a sealing ring 141 to a press member 142 against which the tube member
164
is pressed when the adapter 133 is screwed far enough into the apparatus.
Screwing
the cartridge 14 results in a longitudinal displacement of the adapter
relative to the
threads 140 of the apparatus 1 and, consequently, results in a longitudinal
displace-
ment of the cartridge 14 relatively to the apparatus 1. If the cartridge 14 is
screwed
into the apparatus 1, the tube member 164 is pushed into the space 114
providing pas-
sage between the space 114 through one or more of the release channels 117a,
117b,
117c and into the entrance channel 143 of the apparatus 1.
In prior art gas valve arrangements or aerosol valve arrangements, the tube
member
164 has an outer diameter of 2.76 mm, 3.08 mm, 3.70 mm, 4.70 mm, or 5.15 mm.
By
providing a cartridge with a different diameter of the tube member 164, for
example
4.00 mm, the cartridge 14 can be designed to only function correctly in
connection
with a certain type of apparatus.
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Practical experiments have shown that a fine adjustment threading between the
adapter
133 and the apparatus 1 leads to a smoothly adjustable gas flow over the
diameter of
the release opening 117a, 117b, 117c. Such release opening can also be
produced elon-
gate along the pressing direction, such that a smooth adjustment of the gas
flow rate
can be performed over a larger pressing distance.
With reference to FIG. 19b and FIG. 20, the gas pressure from the gas in the
tube
member 4, 4' pushes against rubber ball 44 such that it is displaced form its
seat 169
for letting gas pass around it into and into nozzle 16 being part of a venturi
55. In case
of overheating of the apparatus 1, a bimetallic plate 47 is deformed in its
seat 170 due
to the heat and pushes the rubber ball 44 back against the gas flow in order
to reduce
the gas flow such that a safe operating temperature can be assured for the
apparatus 1.
As illustrated in FIG. 19a, the container 2 is protected by a bottom cap 148.
Instead of using the engagement between threads 140 of the apparatus 1 and the
threads 134 of the adapter 133 for longitudinal distance adjustment of the
cartridge 14
relatively to the apparatus 1, a different mechanism may be provided. This is
illus-
trated in FIG. 20a and 8b.
In FIG. 20a, an embodiment is shown, where a protection tube 151 surrounds the
car-
tridge 14 and is fastened to the apparatus 1. FIG. 20b is an enlarged partial
view,
where most of the parts of the apparatus are not shown. With reference to FIG.
20a, an
end part 152 of the protection tube 151 has outer threads 153 engaging with
inner
threads 149 of the end cap 148. By turning the end cap 148, the engagement
between
the threads 149 and 153 displaced the end cap relatively to the protection
tube 151 by
which a bottom plate 150 displaces cartridge 14 relatively to the apparatus 1.
In this
case, no cup insert 105 is inserted into the cavity 3' of the valve cup 3. The
adapter
133 of FIG. 19b is substituted by a different adapter 133', which in the
embodiment of
FIG. 20b is fastened to the apparatus 1 in the same way as the adapter in FIG.
19b,
however, as there is no cup insert 165 in the embodiment of FIG. 20b, the
purpose of
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the adapter is a sliding guidance between a cylindrical part of the valve cup
165 and a
cylindrical surface of the adapter 133'.
By surrounding the cartridge 14 with a protection tube 4, the cartridge 14 is
protected
against damage from the outside. In addition, an efficient heat exchange can
be
achieved between the emission gas and the intake air. Furthermore, the
cartridge can
be heated by the emission gas, which is relevant in cold regions. These
advantages will
be described in more detail below.
FIG. 20b illustrates a situation, where the tube member 164 has been pressed
so far
into the space 114 that the first release channel 117a is just about to
connect the space
14 with the inner channel 113 of the tube member 164.
The cartridge is useful for a catalytic burner as disclosed in International
patent appli-
cation WO 2007/085251, the disclosure of which is included herein by
reference. In
the prior art catalytic burner of WO 2007/085251, there is provided a
regulator with a
valve for release of fuel gas operated by an external button. However, in
connection
with the stepwise regulation mechanism of the cartridge, this regulator can be
avoided,
because the cartridge itself has a stepwise regulation function. All other
parts can be
retained.
The catalytic process produces a great amount of infra-red radiation, which is
being
transmitted through the fluid-proof, infrared-transparent material of the
heating pipe 5
and into the fluid container 163. The medium, for example water containing
liquid, in
the container 163 is exposed to the infra-red radiation that especially heats
the medium
in the container 163. In order to ensure an effective utilization of the infra-
red radia-
tion, the container 163 may be provided with a reflective coating on the
inside in order
to reduce the emission of heat through the wall of the container 163.
Furthermore, it is
possible to construct the container 163 with a heat insulating wall,
optionally with a
multi-layered structuring as known from thermo-isolated bottles.
The quality of the catalytic process is depending on the amount of gas
delivered to the
catalytic burner, as the burner demands different amounts of gas in dependence
of the
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surrounding temperature and the required performance of the apparatus 1. The
deliv-
ered gas rate is adjusted as explained as above in connection with FIG. 19 and
FIG.
20.
With a heat insulating container 163 and a handle 51 that is barely heated, it
is difficult
to trace the use of such heating system 1 in connection with military action,
because
the emission of heat, by this way, is minimised. A certain kind of emission of
heat that
implies a potential risk of tracing during application is associated to the
heated emis-
sions (gas, water vapour) from the known catalytic process through the exhaust
open-
ing 170. To reduce the temperature of the emission gases there is provided a
counter
flow heat exchanger 171 that, at least in part, encloses the gas cartridge 14
in order to
transform heat from the exhaust emissions to the gas in the gas tank.
Moreover, the
pipeline 169 for the emission gas is, at least in part, surrounded by the
pipeline 161 for
the intake air through the inlet port 162. Accordingly, heat is transferred
from the
emission gases to the gas cartridge 14 and to the intake air, which
contributes towards
an optimal combustion. In this connection it should be mentioned that the gas
from the
gas cartridge 14 during expansion after the nozzle in the venturi system 55
entails a
cooling of the gas so that absorption of substantial amounts of heat from the
exhaust is
possible.
Emission of heat from the emission gas to the intake gas and the gas cartridge
14 con-
tributes towards ensuring an expedient function of the heating system also in
very cool
surrounding. Therefore, the heating system is well suited for use both in hot
and cool
areas and due to its robust nature it is well suited for use in the military
sector.
FIG. 21 illustrates a further embodiment of the catalytic burner, wherein a
pressure
regulator 146 is implemented in the catalytic burner. The cartridge has a
female
adapter 197 with an internal tube member 164' for release of fuel from the
cartridge
14. The internal tube member 164' of the cartridge 14 is pressed in the
direction into
the cartridge 14 by a mail adapter 196 such that gas is released through the
male
adapter into valve system 198. In valve system 198, a valve member 199 closes
for gas
exit into adjacent chamber 195 unless press member 155 presses against valve
mem-
ber 199. In operation conditions, this press member 155 presses valve member
199 in
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the direction of the cartridge such that fuel gas is released through valve
system 198
and into adjacent chamber 195. A certain predetermined amount of the gas
enters from
adjacent chamber 195 into channel 139 and further into the venturi system 55.
The
pressure on the valve member 199 is determined by the force of a spring 157
against a
resilient rubber membrane 194 which holds the press member 155 resiliently in
posi-
tion. If the pressure in adjacent chamber 195 increases, the press member 155
is resil-
iently pushed in a direction away from the cartridge towards spring 157, by
which the
valve member 199 is also moved in a direction away from the cartridge 14 with
the
result that the flow through the valve system 198 is reduced. When the
adjacent cham-
her 195 is emptied for gas again through channel 139, the pressure in adjacent
cham-
ber 195 decreases, and spring 157 presses press member 155 more against the
valve
member 199, which again increases the flow. This system passively regulates
the pres-
sure in adjacent chamber 195 and works as a passive flow regulator independent
of
temperature and independent of the gas pressure in the cartridge.
As illustrated in FIG. 20 in analogy to FIG. 19b, the gas pressure from the
gas pushes
against rubber ball 44 such that it is displaced form its seat 169 for letting
gas pass
around it into and into nozzle 16. In case of overheating of the apparatus 1,
a bimetal-
lic plate 47 is deformed in its seat 170 due to the heat and pushes the rubber
ball 44
back against the gas flow in order to reduce the gas flow such that a safe
operating
temperature can be assured for the apparatus 1. Also, the bimetallic disc 47
is config-
ured to changing shape when the temperature of the heated medium reaches a
prede-
termined temperature, for example 90 degrees centigrade. This is achieved by
influ-
ence of the temperature of the heated medium around the infrared transparent
tube 5
which is in thermal contact with the bimetallic plate 47 through the metallic
housing,
which preferably is made of aluminium with a good thermal conductivity.
Further-
more, it should be noted that in the situation where pipe 5 is not
sufficiently sur-
rounded by liquid to take up the irradiated heat from the catalytic burner,
the emission
gas 173 will have a higher temperature than under correct operation of the
burner. This
higher temperature, also, leads to a deformation of the bimetallic plate 47
which re-
sults in a reduction or even shut of the gas supply, which is an additional
safety meas-
ure against overheating of the apparatus. The bimetallic plate, thus, has a
triple safety
function.
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Further details that are illustrated in FIG. 20 are a spring calibrated
pressure relief
valve 156 as an overpressure safety arrangement, a heat shield 159 preferably
with low
thermal conductivity, and a thermo-isolating ceramic tube shield 171.
FIG. 22 illustrates an improved air intake and emission gas outlet system with
a dou-
ble tube system for heat recovery around the cartridge 14. The heating
apparatus 1
itself with the catalytic heater is not shown. Essential for this illustration
is the flow
172 of the gas from the catalytic heater 1. This gas is not exhausted at the
site of the
catalytic heater 1 but returned to the outer wall 162 of the cartridge 14,
which is illus-
trated by arrows 172, 173. The hot exhaust indicated by arrow 172 is led along
the
outer side of the wall 2 of the cartridge 14, which is illustrated by arrows
173 by which
the emission gas 172 gradually looses its heat towards the bottom plate 150 of
the end
cap 148, where the emission gas 172 is released to atmosphere. The outer wall
108 of
the cartridge 14 is preferably made of a material with proper heat conduction,
for ex-
ample aluminium. Thus heat is transferred to the gas inside the cartridge 14,
which
improves the gas flow out of the tube member 164 of the cartridge 14. It also
counter-
acts the loss of heat due to evaporation/expansion of the gas when' leaving
the car-
tridge 14.
During flow of the hot emission gas along the wall 162, the gas 172 is cooled
by the
heat exchange with the wall 162 before being released to atmosphere through
exit
openings in the end cap 148, which is illustrated by arrows 174. As these
openings are
directed radially outwards from the end cap 148, mixing with the surrounding
air is
almost instantaneous, such that infrared tracing of the heater is made
difficult due to a
reduced and blurred signal because of the mixing with the cold surrounding
air.
As an additional means to recover the heat from the catalytic burning, air
taken in for
catalytic burning flows - illustrated by arrow 175 - into the tube 161 and is
heated by
the emission gas 172 through a heat conducting partition wall 176, before it
flows -
illustrated by arrow 177 - to the catalytic heater. This measure reduces the
temperature
of the emission gas further, which minimises the possibility of thermally
tracing the
heater in military operations.
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Though use of the cartridge above has been explained above in connection with
hand
held, portable catalytic heaters, this is in no way limiting for the
invention. Such a car-
tridge may be used as an aerosol cartridge as a substitution for prior art
cartridges in
the different fields of application.
When used in connection with a catalytic heater, the application may extend
into a
heater for liquid in a water-tight flexible bag in order to heat up liquid in
the bag by
the heater. For example, a bag may be provided for heating water or other
liquids, such
as
- water for cleaning,
- medical infusion liquids,
- water used in body-tight circulation systems for heating human bodies,
optionally
incorporated in the garment/clothing of a person,
- general water provision by melting snow in a bag or other type of container.
