GB2195018A - Stoves - Google Patents

Abstract

A stove has a body which houses a primary burning chamber (10) and a secondary burning chamber (12). A heat exchanger (14) is disposed between the chambers (10, 12) so as to be exposed to heat generated in both chambers (10, 12). The stove is preferably a solid fuel stove and the heat exchanger a water jacket which forms a dividing wall between the chambers. The preferred stove has preheated air introduced at the top of the primary burning chamber (10) where primary combustion occurs, the combustion gases passing down through a passage (18) under the water jacket to the secondary burning chamber (12) where additional air is added for secondary combustion, the combustion gases being vented through a flue outlet (64) at the top of the secondary burning chamber (12). <IMAGE>

Description

opening into the top of the primary burning chamber to deliver air for combustion to that chamber. This conduit can be in the form of one or more tubes or ducts of circular or other cross-sectional shape and can pass up one or both sides of the primary burning chamber or elsewhere to enable the preheating of the combustion air. Some of this combustion air passes from the conduit 42 through one or more outlets 52 to the secondary burning chamber to provide combustion air for the secondary combustion which occurs in that chamber. Thus, the paths followed by the combustion air are indicated by the arrows A in the drawing. The path followed by the combustion or exhaust gases is shown by the arrows B in the drawing.It can be seen that in the preferred form of the invention illustrated the flames are drawn down from the primary burning chamber 12, under the heat exchanger 14 and up into the secondary burning chamber where more air is mixed with the combustion gases to create a secondary burn.

This arrangement minimizes smoking problems.

The heat exchanger is preferably adapted for the heating of water in which case it can be in the form of a jacket comprising, for example, a non-corrosive copper tank having a cold water inlet 54 at the bottom and a hot water outlet 56 at the top. This inlet and outlet can be connected to a household hot water system, which can include other means for heating water such as an electric or gas hot water cylinder. Copper fins 58 are preferably attached to the back of the water jacket to project out into the secondary burning chamber to buffet the exhaust gases and thereby increase heat absorption through to the water. Steel baffles 60 can be placed on the back wall 62 of the secondary burning chamber to "bounce" the exhaust gases back to the water jacket again.These fins and baffles are preferably arranged alternately to provide a zig-zag path through the secondary burner for the exhaust gases which eventually leave the burner by the flue 64.

Thus, according to the present invention, the placement of the water jacket or other heat exchanger allows the heat from both burning chambers to be utilised for heating water. This provides very effective water heating. With a burner designed for household use it is possible to obtain a water heating output of about 4 to 5 kilowatts depending on the fire. An equivalent size of burner having a conventional wetback typically has a water heating output nearer 1 kilowatt.

The above describes the preferred form of the invention and indicates some possible modifications but other modifications can be made without departing from the scope of the invention as has been broadly defined. Obviously the burner need not be provided with a cooking top and it can be adapted to burn other than solid fuels. Other liquids can be passed through the heat exchanger to be heated and indeed even gases can be heated by the burner of the present invention. A feature of the invention is that the fluid path through the heat exchanger is isolated from the burning chambers so that, at least within the burner. there is no mixing of the fluid passing through the heat exchanger with the combustion air or combustion or exhaust gases.

The air fed to the burning chambers may not be preheated although this is preferred and where the burner has dampening means a separate damper can be provided for controlling air flow rate into each of the burning chambers.

A door in the front of the body can be used to place fuel in the primary burning chamber, especially if there is no openable top, and air can be introduced into the burning chambers in places other than the places specified in relation to the preferred embodiment of the invention.

CLAIMS 1. A burner having a body housing a primary burning chamber, a secondary burning chamber, a passage connecting the burning chambers for combustion gases to pass through, and a heat exchanger disposed between the burning chambers so as to be exposed to heat generated in both burning chambers when the burner is used, the heat exchanger having a fluid path therethrough for fluid to be heated which path is isolated from the burning chambers.

2. A burner as claimed in claim 1 wherein the burner has means whereby fuel can be fed to the primary burning chamber, means whereby air can be fed to the primary burning chamber, and means whereby air can be fed to the secondary burning chamber, and wherein primary combustion occurs in the primary burning chamber, combustion gases therefrom passing through the passage to the secondary burning chamber to mix with air fed thereto to undergo secondary combustion in the secondary burning chamber.

3. A burner as claimed in claim 2 wherein the burner is a solid fuel burner.

4. A burner as claimed in claim 2 or claim 3 wherein the burner has a cooking top to be useable as a stove.

5. A burner as claimed in claim 4 wherein the cooking top is operable to the primary burning chamber providing said means whereby fuel can be fed to the primary burning chamber.

6. A burner as claimed in any one of claims 2 to 5 wherein the air fed to the primary burning chamber enters at or near the top of that burning chamber.

7. A burner as claimed in claim 6 wherein the passage connects the burning chambers at SPECIFICATION A burner The present invention is concerned with im provements in or relating to a burner. The burner is preferably, though not necessarily, a solid fuel burner such as a chip heater. Depending on the design of the burner it can be used for heating and/or cooking.

Burners are known which are designed to provide a source of hot water. Such a burner typically has a burning chamber with a wetback. The wetback is usually in the form of a jacket through which water to be heated flows in use and which functions as a heat exchanger, transferring heat generated in the burning chamber through to the water in the jacket. A disadvantage of this is that usually only a small part of the jacket functions as a heat exchanger.

Burners are also known which have two burning chambers. A typical arrangement is to have the primary burning chamber towards the front of the burner and the secondary burning chamber towards the back of the burner. Typically this type of burner is a solid fuel burner and the solid fuel is placed in the primary burning chamber where the primary burn occurs. Air for combustion passes from outside the burner through a duct or conduit to the primary chamber and may be pre-heated. The hot gases formed in the primary burning chamber flow through to the secondary burning chamber to which combustion air, which again may be pre-heated, is provided so that a secondary burn occurs in that chamber.

From that secondary burning chamber the hot gases usually pass to a flue pipe or chimney.

This type of burner can also be designed to heat water in which case it is usually the secondary burning chamber that is provided with a wetback. However, this burner suffers from the same disadvantage mentioned above in relation to the heating of water.

It was with this disadvantage in mind that the present invention was devised.

The present invention broadly consists in a burner having a body which houses a primary burning chamber, a secondary burning chamber, and a heat exchanger disposed between the burning chambers so as to be exposed to heat generated in both burning chambers when the burner is used, the heat exchanger having a fluid path therethrough for the fluid to be heated which path is isolated from the burning chambers.

Preferably the burner is a solid fuel burner which has a cooking top to be useable as a stove.

Preferably the heat exchanger is a water jacket and the heat exchanger provides a dividing wall between the primary and the secondary burning chambers.

The heat exchanger may have fins attached which extend into the secondary burning chamber and the wall of the secondary burning chamber opposite the heat exchanger may have baffles which extend into the secondary burning chamber. Where the burner has both fins and baffles these are preferably arranged alternately to provide a zig-zag path through the secondary burning chamber for the hot gases.

The above gives a broad description of the present invention a preferred form of which will now be described with reference to the accompanying drawing which shows a crosssectional view, from the side, through the burner.

The preferred burner shown in the drawing has a primary burning chamber 10 and a secondary burning chamber 12. A heat exchanger 14 is disposed between the two burning chambers so as to be exposed to heat generated in both burning chambers when the burner is being used. In the preferred burner the heat exchanger provides the dividing wall between the primary and the secondary burning chambers so that it is directly exposed to the flames in both chambers. In the preferred construction shown in the drawing the heat exchanger extends to the tops of the burning chambers but stops short of the bottom 16 of the burning chambers on which the ash bed forms. Thus, a passage 18 passes between the bottom ends of the burning chambers.

The burning chambers and the heat exchanger are housed within the body of the burner. This body comprises a front 20, a top 22, a base 24 and opposite sides which are not shown. The base can be mounted on feet 26. Heat shields 28, 30 and 32 are preferably disposed between the burning chambers and the front, and the base of the burner, and at the back of the burner respectively. Similar heat shields are preferably disposed between the burning chambers and the sides of the burner.

The top of the burner is preferably provided with a solid steel cook top so that the burner can be used as a stove. The preferred burner has the cook top constructed to be capable of being lifted to open the top of the primary burning chamber to allow solid fuel such as logs 34 to be dropped into that burning chamber, The cooking top has a heat insulated handle 36 attached to enable it to be lifted while the burner is in use.

The back of the burner has one or more apertures 38 through which ambient air can be drawn to an aperture 40 in the bottom end of a conduit 42. The degree of opening of the aperture 40 is controlled by a damper 44.

This damper is mounted at one end of a member 46 which extends through to the front of the burner and has a burning control lever 48 attached.

The conduit 42 passes up to an outlet 50

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   SPECIFICATION A burner The present invention is concerned with im provements in or relating to a burner. The burner is preferably, though not necessarily, a solid fuel burner such as a chip heater. Depending on the design of the burner it can be used for heating and/or cooking.

   Burners are known which are designed to provide a source of hot water. Such a burner typically has a burning chamber with a wetback. The wetback is usually in the form of a jacket through which water to be heated flows in use and which functions as a heat exchanger, transferring heat generated in the burning chamber through to the water in the jacket. A disadvantage of this is that usually only a small part of the jacket functions as a heat exchanger.

   Burners are also known which have two burning chambers. A typical arrangement is to have the primary burning chamber towards the front of the burner and the secondary burning chamber towards the back of the burner. Typically this type of burner is a solid fuel burner and the solid fuel is placed in the primary burning chamber where the primary burn occurs. Air for combustion passes from outside the burner through a duct or conduit to the primary chamber and may be pre-heated. The hot gases formed in the primary burning chamber flow through to the secondary burning chamber to which combustion air, which again may be pre-heated, is provided so that a secondary burn occurs in that chamber.

   From that secondary burning chamber the hot gases usually pass to a flue pipe or chimney.

   This type of burner can also be designed to heat water in which case it is usually the secondary burning chamber that is provided with a wetback. However, this burner suffers from the same disadvantage mentioned above in relation to the heating of water.

   It was with this disadvantage in mind that the present invention was devised.

   The present invention broadly consists in a burner having a body which houses a primary burning chamber, a secondary burning chamber, and a heat exchanger disposed between the burning chambers so as to be exposed to heat generated in both burning chambers when the burner is used, the heat exchanger having a fluid path therethrough for the fluid to be heated which path is isolated from the burning chambers.

   Preferably the burner is a solid fuel burner which has a cooking top to be useable as a stove.

   Preferably the heat exchanger is a water jacket and the heat exchanger provides a dividing wall between the primary and the secondary burning chambers.

   The heat exchanger may have fins attached which extend into the secondary burning chamber and the wall of the secondary burning chamber opposite the heat exchanger may have baffles which extend into the secondary burning chamber. Where the burner has both fins and baffles these are preferably arranged alternately to provide a zig-zag path through the secondary burning chamber for the hot gases.

   The above gives a broad description of the present invention a preferred form of which will now be described with reference to the accompanying drawing which shows a crosssectional view, from the side, through the burner.

   The preferred burner shown in the drawing has a primary burning chamber 10 and a secondary burning chamber 12. A heat exchanger 14 is disposed between the two burning chambers so as to be exposed to heat generated in both burning chambers when the burner is being used. In the preferred burner the heat exchanger provides the dividing wall between the primary and the secondary burning chambers so that it is directly exposed to the flames in both chambers. In the preferred construction shown in the drawing the heat exchanger extends to the tops of the burning chambers but stops short of the bottom 16 of the burning chambers on which the ash bed forms. Thus, a passage 18 passes between the bottom ends of the burning chambers.

   The burning chambers and the heat exchanger are housed within the body of the burner. This body comprises a front 20, a top 22, a base 24 and opposite sides which are not shown. The base can be mounted on feet 26. Heat shields 28, 30 and 32 are preferably disposed between the burning chambers and the front, and the base of the burner, and at the back of the burner respectively. Similar heat shields are preferably disposed between the burning chambers and the sides of the burner.

   The top of the burner is preferably provided with a solid steel cook top so that the burner can be used as a stove. The preferred burner has the cook top constructed to be capable of being lifted to open the top of the primary burning chamber to allow solid fuel such as logs 34 to be dropped into that burning chamber, The cooking top has a heat insulated handle 36 attached to enable it to be lifted while the burner is in use.

   The back of the burner has one or more apertures 38 through which ambient air can be drawn to an aperture 40 in the bottom end of a conduit 42. The degree of opening of the aperture 40 is controlled by a damper 44.

   This damper is mounted at one end of a member 46 which extends through to the front of the burner and has a burning control lever 48 attached.

   The conduit 42 passes up to an outlet 50

   or near their bottom ends so that combustion gases are drawn down the primary burning chamber to pass through the passage and up the secondary burning chamber to a flue outlet at or near the top of the secondary burning chamber.

   8. A burner as claimed in any one of claims 2 to 7 wherein the heat exchanger provides a dividing wall between the primary and the secondary burning chambers and the passage passes under the heat exchanger.

   9. A burner as claimed in any one of claims 2 to 8 wherein the heat exchanger has fins which extend into the secondary burning chamber.

   10. A burner as claimed in claim 9 wherein the secondary burning chamber has a wall opposite the heat exchanger from which wall baffles extend into the secondary burning chamber.

   11. A burner as claimed in claim 10 wherein the fins and baffles are arranged alternately to provide a zig-zag path through the secondary burning chamber for the combustion gases.

   12. A burner as claimed in any one of claims 2 to 11 wherein the heat exchanger is a water jacket having a cold water inlet and a hot water outlet.

   13. A burner as claimed in any one of claims 2 to 12 wherein the burner has dampening means to control air flowrate to either one or both of the burning chambers.

   14. A burner as claimed in any one of claims 2 to 13 wherein the air fed to either one or both of the burning chambers passes through one or more conduits exposed to heat generated by the burner in use to preheat the air before it enters the respective one or both of the burning chambers.