GB2451521A

GB2451521A - Heater with Combustion Chamber and Thermoelectric Powered Blower

Info

Publication number: GB2451521A
Application number: GB0715310A
Authority: GB
Inventors: Sean Paul Duffy; Michael Frank Palmer
Original assignee: ALPINE ENERGY Ltd
Current assignee: ALPINE ENERGY Ltd
Priority date: 2007-08-03
Filing date: 2007-08-03
Publication date: 2009-02-04
Also published as: GB0715310D0

Abstract

A heater has a combustion chamber 10 in which a fuel is burned to provide a source of heat. The combustion chamber has a fuel burner 12, and an air blower 22 delivers air to the burner. The blower is powered by a thermoelectric generator 18, i.e. a Peltier-Seebeck device, and the device has a hot side 18a heated by heat from the burner and a cold side 18b cooled by air from the blower. Fuel may be supplied from a liquid reservoir, such as a jerry can 14 containing diesel oil or kerosene, and the heater includes a regulator 16 which regulates fuel delivery to the burner. The regulator may include a fuel chamber with a float valve to maintain fuel flow within a safe limit, and the regulator may be manually adjustable. A water tank 28 may be releasably secured to the top of the combustion chamber, and removal of the water tank may provide access to the combustion chamber to allow the burner to be manually ignited. The heater may be used by the military as a portable heater, for example, to provide hot water or space heating in a field kitchen or on a boat.

Description

Portable Heater

This invention concerns portable fuel-fired heaters, suitable particularly but not necessarily exclusively for use by troops in the field.

To be portable, a heater must be relatively compact, which means that it cannot have a tall flue to draw combustion air through the heater. If the supply of combustion air is insufficient in relation to the fuel supply the fuel will burn inefficiently and the output from the flue will be dirty. (As well as both economic and environmental desirability of clean combustion, for military use it is also important to minimise any output that could be detected by enemy forces or weapons). The need for combustion air to at least a clean combustion level can be met by providing a fan to deliver combustion air to the heater, but portability demands that such a fan cannot be driven from an external source of power.

It is therefore an object of the present invention to provide a portable heater which is (a) compact and does not require a tall flue, (b) efficient in operation and (c) self-powered in that its operation does not does not require an external power source. S...

Thus according to the invention there is provided a self-powered heater comprising a combustion chamber, a fuel burner in the combustion chamber, a thermoelectric generator and an air blower powered by the thermoelectric generator and operative to deliver combustion air to the fuel : burner, characterised in that the thermoelectric generator comprises a Peltier-Seebeck device having a hot side heated by heat from the burner and a cold side cooled by air from the blower.

Preferably the heater is configured and arranged to burn liquid fuel, eg diesel oil or kerosene, and the heater includes a regulator operative to regulate delivery of the liquid fuel to the burner. The regulator may comprise a fuel chamber containing a float valve operative to increase the delivery of fuel if the fuel in the chamber falls below an operating level and to decrease the delivery of the fuel if the fuel in the chamber rises above an operating level and a closure device operative by the float valve to shut off the delivery of fuel if the fuel in the chamber rises above a safety limit. The regulator may be manually adjustable, not only to vary the burner setting but also to deliver a starter quantity of liquid fuel to the burner before the burner is ignited.

The combustion chamber is preferably configured and arranged to provide access to the burner whereby the starter quantity of fuel may be lit to ignite the burner by means of a spill or the like.

The fuel may be gravity-fed to the burner.

A heater according to the invention may be used in a variety of applications such as a field kitchen of a space heating system for use in the field or on a boat, but the invention has been developed particularly for heating water and for this purpose a water tank may be mountable above the combustion chamber. This water tank may be formed with a passage for combustion products from the combustion chambers, whereby water in the tank is heated. The passage for the combustion products may be serpentine and have a proximal end configured and arranged for sealing engagement * with the combustion chamber and a distal end from which in use the *** combustion gases exhaust to atmosphere. To ensure that the combustion products are dispersed away from users of the heater, a short flue may be *** * engageable with the distal end of the passage.

Other features of the invention will be apparent from the following description, which is made by way of example only with reference to the accompanying schematic drawings in which -Figure 1 illustrates a self-powered water heater embodying the invention and Figure 2 illustrates a regulator for regulating the supply of liquid fuel to the heater of Figure 1.

Referring first to Figure 1, the invention comprises a combustion chamber 10 within which is a fuel burner 12 bums diesel oil delivered from a jerry can 14 by way of a regulator 16. (Diesel fuel is recommended for use in the invention because it is comparatively inexpensive, widely available and easy to handle. However other liquid fuels may be used, kerosene for instance, or otherwise gas or even solid fuels might be used). The jerry can 14 is supported upon a stand (not shown) or otherwise raised above the level of the burner 12 to which thereby the diesel fuel is gravity-fed.

A Peltier-Seebeck thermoelectric generator 18 extends vertically adjacent the combustion chamber 10. The thermoelectric generator 18 comprises a stack of bismuth telluride (Bi-Te) semiconductor modules connected in series that generate an electrical voltage when there is a temperature difference across the stack. Thus the thermoelectric generator 18 has a hot side ISa facing towards the combustion chamber 10 to be heated by I...

heat from the burner 12 and a cold side 18b facing away from the combustion chamber 10 and into a plenum chamber 20. The cold side 18b is cooled as will be described hereinafter. Modules suitable for the thermoelectric generator 18 :. are made by Thermonamic Electronics (Xiamen) Company Limited and * available from Xiamen Taihuaxing Trading Company Limited. S..

An electrically powered air blower 22 is positioned in the wall of the plenum chamber 20 and arranged to blow air from outside into the plenum chamber 20, which is thereby pressurised. As indicated by arrows A, the air blown into the plenum chamber 20 is first of air directed on to the cold side 18b of the thermoelectric generator 10 and thereby serves to cool this side 18b. By this means, with the other side 18a of the thermoelectric generator 18a heated by heat from the burner 10, a temperature difference is in use maintained across the thermoelectric generator 18 and the output from this drives the air blower 22. Thus the air blower 22 is electrically connected across the thermoelectric generator 18 by leads 24 so as to be powered by the electrical output from the thermoelectric generator 18. A meter 26 is (optionally) included in one of the leads 24 to indicate the power delivered by the thermoelectric generator 18.

After cooling the cold side 18b of the thermoelectric generator 18 the air from the air blower 22 continues as indicated at B through the plenum chamber 20 to provide combustion air for the burner 12, the fuel burning as indicated at 26 in the combustion chamber 10.

On top of the combustion chamber 10 is a water tank 28 having a double wall (indicated by broken lines at 30) providing a passage for combustion gases C rising from the burner 12. Baffles 32 within the double wall 30 make the passage serpentine so that the combustion gases turn backwards and forwards as indicated by arrows D thereby to heat water in the I...

tanks 28. The proximal end of the serpentine passage is surrounded by a seal 34 whereby it is sealingly engaged with the combustion chamber 10. At the *..

distal end of the serpentine passage is a flue box 36 supporting a short flue 38 whereby the combustion gases vent to atmosphere.

Control of the supply of diesel fuel to the burner 12 by the regulator 16 will now be described briefly with reference to Figure 2. A suitable regulator is the BM3O Safety and Control Valve available from Karl Dungs GmbH & Co KG. As shown purely schematically in Figure 2 the regulator 16 comprises a fuel chamber 40 having connections for a fuel inlet pipe 42 and a fuel outlet pipe 44 respectively (see also Figure 1). The inlet pipe 42 is connected to a metering duct 46 alternatively openable and closable by a shut-off valve 48 manually operable by a control lever 50 extending through the wall of the fuel chamber 40. Within the fuel chamber 40 is a float 52 which floats on fuel in the chamber 40 at an operating level E. A tapered valve stem 54 extends upwards from the float 52 and into a correspondingly shaped valve seat 56 of the metering duct 46. If the level of fuel in the chamber 40 falls below the operating level E, the float 52 drops and the stem 54 moves out of the seat 56 to admit fuel to the chamber 40 at an increased rate and thereby restore its level. Conversely, if the level of fuel in the chamber 40 rises above the operating level E, the float 52 rises and the stem 54 moves into the seat 56 to reduce the admission of fuel to the chamber 40 and thereby restore its level. A closure arm 58 extends upwards from the float 52 and is so arranged that if the fuel in the chamber 40 rises above a safety limit F then the arm 58 lifts the lever 50 to shut off the fuel supply. The water tank 28 is releasably :. secured to the top of the combustion chamber 10 by catches (not shown) and it is provided with handles (not shown) whereby it may be lifted off the *...

combustion chamber 10. As well as allowing hot water in the water tank 28 to * be carried to a point of use, this enables the water tank 28 to be removed to provide access to the combustion chamber 10 to allow the burner to be manually ignited. By means of an adjuster 60 the metering duct 46 can be adjusted up and down, which serves to vary the operating level E and more generally the rate of delivery of fuel by the regulator 16.

For initial ignition of the burner 12, the water tank 28 is lifted off to provide access to the combustion chamber 10. The control lever 50 of the regulator 16 is then pressed down until a small pool of diesel oil forms in the bottom of the burner 12. This is ignited with a lighted spill or the like and, when it is properly alight, the water tank is put back in place. Within a short period, the heat from the burner heats the hot side 18a of the thermoelectric generator 18 which then generates power to operate the air blower 22. In turn the air blower 22 both cools the cold side 18b of the thermoelectric generator 18 and delivers combustion air to the burner 12. From this point the heater can continue to operate at maximum efficiency until the regulator 16 is turned off by means of the control lever 50.

It will now be appreciated that the invention provides a water heater which is compact, efficient in operation and self-powered. With such features, the heater is particular useful to military personnel in the field. It may be used in a variety of ways including heating sanitary water (for washing and cleaning), as a space heater or as part of a field kitchen.

The self-powered heater as described above uses manual ignition principally for reasons of simplicity and reliability (which those skilled in military science will appreciate are of particular importance in the field). S...

However the heater may be modified to include a rechargeable electrical *:*::* battery charged from the thermoelectric generator and such a battery may be . arranged to power the air blower during an intermediate warm-up period from :. ignition of the burner until the thermoelectric generator generates sufficient * power for the blower -thereby providing a cleaner flue output during that S..

period -and/or to power an electrical igniter for the burner.

Various modifications are possible. For instance, to provide forced combustion and therefore a clean flue output during the warm-up period, a manually operated generator may be connected to the air blower 22 for operation during that period. Electrical connections may be provided to power lighting or other equipment from the thermoelectric generator 18. A thermostat may be provided with a temperature sensor in the water tank 28 and operatively connected to the regulator so that the temperature of water in the tank 28 is brought to and maintained at a set temperature.

Other possible additions and modifications will be apparent to those skilled in the science. S. * . * ... * * I... * .* *. . * SS S..

S *. * S * S.. *.*

Claims

Claims 1. A self-powered heater comprising a combustion chamber, a fuel burner in the combustion chamber, a thermoelectric generator and an air blower powered by the thermoelectric generator and operative to deliver combustion air to the fuel burner, characterised in that the thermoelectric generator comprises a Peltier-Seebeck device having a hot side heated by heat from the burner and a cold side cooled by air from the blower.
2. A self-powered heater as claimed in claim I characterised in that the burner is configured and arranged to burn liquid fuel and the heater includes a regulator operative to regulate delivery of the liquid fuel to the burner.
3. A self-powered heater as claimed in claim 2 characterised in that the regulator comprises a fuel chamber containing a float valve operative to increase the delivery of fuel if the fuel in the chamber falls below an operating level and to decrease the delivery of the fuel if the fuel in the chamber rises :. above an operating level and a closure device operative by the float valve to shut off the delivery of fuel if the fuel in the chamber rises above a safety limit. *�.s * S.

S..'..
4. A self-powered heater as claimed in claim 2 or claim 3 S. * 20 characterised in that the regulator is manually adjustable. S. * . * ***
5. A self-powered heater as claimed in claim 4 characterised in that the regulator is manually adjustable to deliver a starter quantity of liquid fuel to the burner before the burner is ignited.
6. A self-powered heater as claimed in claim 5 characterised in that the combustion chamber is configured and arranged to provide access to the burner whereby the starter quantity of fuel may be lit to ignite the burner by means of a spill or the like.
7. A self-powered heater as claimed in any of claims 2 to 6 characterised in that the fuel is gravity-fed to the burner.
8. A self-powered heater as claimed in any of claims 2 to 7 characterised in that the fuel is diesel oil or kerosene.
9. A self-powered heater as claimed in any preceding claim characterised in that a water tank is mountable above the combustion chamber.
10. A self-powered heater as claimed in claim 9 characterised in that the water tank is formed with a passage for combustion products from the combustion chambers, whereby water in the tank is heated.
11. A self-powered heater as claimed in claim 10 characterised in that the passage is serpentine. * ** * S * * *.
12. A self-powered heater as claimed in claim 10 or claim 11 characterised in that the passage has a proximal end configured and arranged :. for sealing engagement with the combustion chamber.
13. A self-powered heater as claimed in claim 12 characterised in that the passage has a distal end from which in use the combustion gases exhaust to atmosphere.
14. A self-powered heater as claimed in claim 13 characterised in that the heater includes a flue engageable with the distal end of the passage.
15. A self-powered heater as claimed in any preceding claim characterised in that the heater includes a rechargeable electrical battery charged from the thermoelectric generator.
16. A self-powered heater as claimed in claim 15 characterised in that the air blower is powered by the electrical battery during an intermediate period from ignition of the burner until the thermoelectric generator generates sufficient output to power the blower.
17. A self-powered heater as claimed in claim 15 or claim 16 characterised in that the heater includes an electrical igniter for the burner, *.i5 which igniter is powered by the electrical battery. * *

**.* . . .
18. A self-powered heater as claimed in any preceding claim *:*::* characterised in that a manually operated generator is connected to the air blower and operative to power the air blower during the intermediate period from ignition of the burner until the thermoelectric generator generates sufficient output to power the blower.
19. A self-powered heater as claimed in any preceding claim characterjsed in that the heater includes electrical connections for lighting or other equipment to be powered from the thermoelectric generator.
20. A self-powered heater substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
21. A water heating system including a self-powered heater as claimed in any preceding claim.
22. A water heating system as claimed in claim 19 characterised in that the delivery of fuel to the burner is regulated thermostatically in response to temperature of the water.
23. A space heating system including a self-powered heater as claimed in any preceding claim.
24. A field kitchen including a self-powered heater as claimed in any preceding claim. * * **** * II * S S * *e * S..

S S. * . * *.* * S..

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