CATALYTIC HEATER

Abstract

A catalytic heating system comprising a main catalyst (20, 50) for flameless catalytic burning of fuel gas and a triggering system for initiating the catalytic burning, the triggering system comprising an electrical power source electrically connected to a metallic catalyst portion (104). 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. 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. As soon as the reaction starts, it is transferred to the main catalyst.

Description

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 electrically 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 U.S. Patent No. 4,510,890 by Cowan, U.S. Pat. No. 4,886,017 by Viani, and U.S. Pat. No. 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 temperature 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 U.S. Pat. No. 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 number 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 adjacent heat exchanger. Therefore, typically, the combustion products are mixed with air in order to reduce the temperature. The problem is described in U.S. Pat. No. 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 systems, when using a combustion chamber. Another disadvantage is the fact that combustion 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 burners also have an afterburner for burning the remaining fuel in the combustion gases.

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 U.S. Pat. No. 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 interesting 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 portable 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 catalytic 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 contact with the heated catalyst. As soon as the reaction starts, the reaction is transferred to the main catalyst.

In contrast to prior art document U.S. Pat. No. 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 catalyst. Especially in connection with prior art, if the main component of the catalyst is ceramics, as in U.S. Pat. No. 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 fowl 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 flameless catalytic heating element can also be safely operated in areas with highly flammable 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, rhodium, 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 advantageous 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 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 section 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 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 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. Experiments 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 supply 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 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.

Catalysis occurs in the temperature range 370-425° C. These temperatures correspond to IR wavelengths about 3-7 μm, which basically coinciding with the maximal absorption spectrum of water, which is in the range of 3-7 μm. 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 water-proof separation between the medium to be heated and the catalytic heating element. 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 example, the partition wall may comprise aluminium, copper or quartz glass or a combination 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 exchanger 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 process.

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 exhaust 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 concept 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 ° C. By way of example, 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 butane 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. Therefore, it is suited for military purpose and extreme sport.

In another embodiment, the catalyst is elongate and extends horizontally or substantially 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.

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 portable, 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 workers, 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 principle
  • 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

In connection with catalytic heaters, especially off grid portable systems are challenging to construct, in as much as a long catalytic burning chamber requires a large diameter 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 systems, but fail for small systems. Experience from large systems with respect to ignition of the catalytic process seems not to be scalable to small systems. This is surprising but has led to the ignition approach according to the invention.

A preferred embodiment is a flameless catalytic burner with a ratio between the diameter 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 immersion 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 system 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 approximate 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.

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 cartridge 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 constant temperature, bimetallic valve elements may be applied. Such regulation is necessary, 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 cartridge 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 opening directed towards the outside of the container and a second opening directed towards 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 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 release, there is provided a simple stepwise adjustable valve into a cartridge. Thus, it is possible to tune the gas flow—with or without aerosols—without the necessity of having a complicated valve arrangement in the apparatus, into which the cartridge is inserted. 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 exchanged 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 gasket, typically a sealing ring, which tightens the second openings against the gas pressure 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 member is pressed towards the container, one opening after the other is pushed to the opposite 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 neighbouring openings by second gasket means. The latter is relevant, if the openings have different 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 another cartridge when emptied and not filled with new gas on site. However, the cartridge 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 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 cartridges.

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 bullet. This minimising of the risk is achieved by providing the cartridge with a low friction 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 developed 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 cartridge is filled with liquid gas only to less than the middle height of the cartridge, liquid 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 countermeasure, the cartridge in a further embodiment comprises a fibrous absorptive material 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 tampon, 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 threads or with means for fastening of cartridges without threads at all. These requirements 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 having 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 configured 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 connection 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 designed 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 dependence of the manufacturer or specific apparatus. This implies that a fuel gas cartridge 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.

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 shoulder 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 required for producing these shoulders, because commercial cartridges are already provided 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 order to protect such tube members, the insert may have a central protection cap for covering a gas exit of the valve arrangement.

Preferably, the insert has a substantially circular cross section with a rim part comprising the wings and the screw threads, which preferably are directed inwards. Advantageously, the protection cap is connected to the rim part by a plurality of bars configured 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 cartridge 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 apparatus. 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 adjustment of the flow.

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 immediately 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 mixing 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 cartridge.

Such a catalytic heater is especially useful for military application, pre-hospital environments, 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 catalyst,

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;

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 apparatus 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 radiation 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 warming 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 heating unit 2 and the container 163 separated from each other, while FIG. 1b 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 advantageously 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 atmosphere 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 handle 4 or into the pipe 5. The safety valve for equalization of pressure may also be located 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 controlled 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. 1b. 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 exhaust of gas is provided via openings in the upper part of the handle, in which there in FIGS. 1a and 1b 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 mixture 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 special 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 intended 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 FIGS. 5 and 6. FIGS. 5a and 5b illustrate end view and side view of a heater system 30 inside which a plane straight catalyst 31 arranged in a liquid 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 multiple inlets 36 in the lower part 37 of the heater system.

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 FIGS. 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 FIGS. 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 furthermore 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 implying 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 ensure 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 provide 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 temperature 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 directly 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 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 embodiments.

FIG. 4a and b illustrate a portable pressurized sterilizer 96 with a pressurisable container 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 container 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 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 U.S. Pat. No. 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 sterilized 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 container for submersing the heating pipe into the liquid in the container, where the opening cooperates with an adapter of the catalytic burner in order to achieve a tight fastening, 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 catalyst 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 regulator 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, outside 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 example 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 provided 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 temperature 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 25° C. at the bottom due to the cold inlet liquid with a temperature of around 15° C. and 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 transparent enclosure 59.

FIG. 9 shows a portable liquid heating bag 75, in a perspective view in FIG. 9a, illustrating 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 example, 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 a cross sectional cut through the flexible bag 75 such that an arrangement with a heating pipe surrounded by an outer tube 76 is visible. The outer tube 76 has lower openings 77 and upper openings 78 such that water or other liquid can flow into an interspace between the heating pipe and the outer tube 76. The heating of the water in this 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 FIGS. 10a and 10b, a likewise system is illustrated, where a liquid box 79 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 closing mechanisms, for example a zip closure, may be used alternatively.

In fact, the liquid heating bag 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 U.S. Pat. No. 4,886,017 by 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 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 cooperates with an adapter of the catalytic burner in order to achieve a tight fastening, for example a screw fastening. Preferably, the heating pipe 5 is surrounded by an outer tube 76 with lower openings 77 and upper openings 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 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 latter embodiment is also useful in connection with the sterilizer as describe above and with the body heater as described below.

In FIG. 11a, 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. 11b 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 liquid enters end exits the heat container through respective openings 87a, 87b. Optionally, 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 U.S. Pat. No. 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 cooperates 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 advantages of the venturi. However, a combination is preferred due to the optimised performance.

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 spherically curved surface. After being burned, the emission gas 57 leaves the burner between 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 container 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 image, FIG. 13a, shows the cup insert 165 outside the valve cup 163, and the lower image, 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 protection 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 detail in FIG. 16a-c.

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 absorbers. 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 configuration. 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 release 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 sectional 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 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 container 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 consuming 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 invention. 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 accommodation of the tube 110 and with a conical part 138 at the one end 137 for facilitating the insertion of the tube 110. FIG. 18b shows the situation when the tube 110 is accommodated 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 deformation 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 tube 110 such that only evaporated gas is released through tube member 164. The absorptive media 109 can be made of various kinds, however, first prototypes used tampons 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 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 apparatus 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 displacement 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 passage 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.

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 elongate 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 illustrated in FIGS. 20a and 8b.

In FIG. 20a, an embodiment is shown, where a protection tube 151 surrounds the cartridge 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 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 application 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 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. 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 surrounding temperature and the required performance of the apparatus 1. The delivered 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 emissions (gas, water vapour) from the known catalytic process through the exhaust opening 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 contributes 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 member 199. In operation conditions, this press member 155 presses valve member 199 in 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 position. If the pressure in adjacent chamber 195 increases, the press member 155 is resiliently 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 chamber 195 is emptied for gas again through channel 139, the pressure in adjacent chamber 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 pressure 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 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. Also, the bimetallic disc 47 is configured to changing shape when the temperature of the heated medium reaches a predetermined temperature, for example 90 degrees centigrade. This is achieved by influence 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. Furthermore, it should be noted that in the situation where pipe 5 is not sufficiently surrounded 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 results in a reduction or even shut of the gas supply, which is an additional safety measure against overheating of the apparatus. The bimetallic plate, thus, has a triple safety function.

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 thereto-isolating ceramic tube shield 171.

FIG. 22 illustrates an improved air intake and emission gas outlet system with a double 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 illustrated 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 example 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 counteracts the loss of heat due to evaporation/expansion of the gas when leaving the cartridge 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.

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 cartridge 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.

Claims

1-22. (canceled)

23. A catalytic heating system (1) comprising a main catalyst (20, 50) for flameless catalytic burning of fuel gas and a triggering system for initiating the catalytic burning, the triggering system comprising an electrical power source electrically connected to an electrically conducting, separate metallic catalyst portion (104) for causing electrical current to flow through the catalytic portion (104) and thereby heating the catalyst portion to a temperature necessary for triggering the catalytic burning at the catalyst portion.

24. A catalytic heating system according to claim 23, wherein the metallic catalyst portion (104) is substantially smaller than the main catalyst (50).

25. A catalytic heating system according to claim 24, wherein the metallic catalyst portion (104) through which current flows has a width and a height and a length, each of which is smaller than 1 mm.

26. A catalytic heating system according to claim 23, wherein the main catalyst (20, 50) is a metallic mesh.

27. A catalytic heating system according to claim 26, wherein the main catalyst (50) is a tubular mesh with varying diameter.

28. A catalytic heating system according to claim 27, wherein the main catalyst is a tubular mesh (50) in the shape of a truncated cone.

29. A catalytic heating system according to claim 23, wherein a venturi system (17, 55) is provided for mix of fuel gas and oxygen, the venturi system comprising a venturi nozzle (16, 44) with a nozzle exit (49), through which fuel gas is provided, and a channel (45) around the venturi nozzle, the channel being formed between the outer wall (75) of the venturi nozzle and a pipe portion (47) surrounding the nozzle, the outer wall of the venturi nozzle being concave and the surrounding pipe portion being convex to form a smoothly bending channel towards the venturi nozzle exit.

30. A catalytic heating system according claim 23, wherein the system is a portable system with integrated fuel tank (162) and comprising a handle (4) and an in extension hereof arranged heating pipe (5) containing the catalyst (20, 50), where the heating pipe is produced in a material that is transparent for infra-red radiation and fluid-proof for immersion in liquids.

31. A catalytic heating system according to claim 23, further comprising a heat exchanger (171) between a fuel tank (162) and an exhaust pipe system for heat exchange between emission gas from the catalytic burning and a wall of the fuel tank, the heat exchanger comprising a flow path for leading the burned gas from the catalyst past the fuel tank.

32. A catalytic heating system according to claim 23, wherein the catalyst (20, 50) is surrounded by a fluid-proof, infra-red transparent enclosure (5) immersed in a liquid tank for heating of liquid in the liquid tank (3) by the infrared radiation from the catalytic burning by the catalyst.

33. A catalytic system according to claim 32, wherein the catalyst is elongate and extends horizontally or substantially horizontally in a bottom area of the tank.

34. A catalytic system according to claim 32, wherein the main catalyst is a conical metallic mesh with a large end towards a bottom of the enclosure (5) and a narrow end of the cone arranged towards a gas exhaust.

35. A catalytic system according to claim 32, further comprising a flow path for intake air and a heat exchanger for heat exchange between hot, burned gas from the catalyst and intake air for the catalyst.

36. A catalytic system according to claim 28, wherein at a lower, wide part of the catalyst mesh there is provided a curved surface 105 for change of direction of fuel gas mixture.

37. A catalytic heating system according claim 23, further comprising a cartridge containing gas with or without aerosols, the cartridge (14) comprising a container (162) for containing the gas and comprising a valve arrangement (164, 112, 113, 114, 115, 116, 127, 117a, 117b, 117c) with a tube member (164) for release of gas with or without aerosols from the container (162) through a channel in the tube member, the valve arrangement comprising and a resilient member (127) providing a resilient force against the tube member (164) directed away from the container, the tube member (164) having an inner channel (113) for release of gas from the container (162, 163) through the channel (113) when the tube member (164) is pressed against the resilient force a distance along a pressing direction towards the inside of the container.