GB2280747A - Oil or gas-burning stove - Google Patents

Abstract

A stove, suitable for domestic use, has a cooker and a boiler (12) individually heated by independently controllable burners (8, 9) which can be turned on and off as required. The user may, therefore, set the burners for heating the boiler or the cooker alone, or both together. Preferably the burners are of a pressure jet type with automatic ignition and thermostatic control. The burners fire into combustion chambers (10, 11) formed at least in part of ceramic material; the chambers, and products of combustion passages (24) leading from them to a flue, being thermally insulated from one another. A roasting oven (5) and a warming oven (4) of the cooker may both be heated directly by products of combustion from the cooker burner (8), or the warming oven may be heated by heat exchange from the roasting oven. <IMAGE>

Description

IMPROVEMENTS RELATING TO OIL OR GAS-BURNING STOVES This invention relates to oil or gas-buring stoves such as are used domestically and comprise in combination a cooker and a boiler for hot water.

It has been usual for stoves of this kind to be kept running continuously 24 hours a day for long periods of service. They have not normally been turned off except for service or repair but instead have simply been turned down to lower heat settings when not needed for cooking or when there is a reduced demand for heated water.

Previously stoves have been known which have had a single burner which has heated both the cooker and the boiler. The arrangement provides limited control of heat for the two functions of the stove. Additionally residual heat from the cooker has invariably been taken up by the boiler with the result that excess heat has been produced for the hot water which has been difficult to disperse.

A burner with dual nozzles to heat the cooker and boiler respectively has been proposed but both nozzles could not be operated effectively at once.

Stoves have also been known which have had two independent well burners to heat the cooker and the boiler. However, these burners were not normally turned off except for service and repair as they were not easy to light and therefore heat was often generated in excess of requirements.

The present invention aims to provide an oil or gas-burning stove which enables better control of heat than has generally been possible in previously known oil or gas-burning stoves.

According to the present invention an oil or gas-burning stove is provided which comprises in combination a cooker and a boiler for hot water and which has oil or gas-fired burners for the cooker and boiler, the burners being individual, independently controllable and easy to turn on and off as required.

The separate burners facilitate control of the heating of the cooker and boiler according to the user's requirements.

Preferably the burners are of a pressure jet type which have oil or gas and air supplied under pressure for combustion, and include automatic ignition means so that the burners can be turned on and off as required.

Each burner is preferably thermostatically controlled, the user setting the control as desired for use. This further improves the control of the heating in the stove, and the efficiency of the heating. Since the relevant burner can be turned off when it is not needed to heat the cooker or boiler, as the case may be, there can be significant saving in oil or gas consumption.

An additional advantage of using burners of the pressure jet type is that a higher level of combustion, and hence a cleaner burn, is possible than can be expected from the more conventional well-type oil burners that have been used in oil-burning stoves in the past. The cleaner burn is environmentally desirable, more efficient in its heating and reduces the level of sooting in the stove.

Conveniently the burners are operated on kerosene but they may possibly be operated on gas oil, or on gas.

The burners preferably fire into chambers formed at least in part of ceramic material, for example ceramic fibre material. The ceramic material reduces heat transfer between the chambers. At least one of the chambers may be formed wholly, or for the most part, of ceramic material, either compositely or as a unitary structure. The burners may extend a short distance into the chambers but the greater part of the volume of the chambers may be free for the burner flames and products of combustion to pass along them.

Dimensional constraints on the stove for it to be consistent with generally accepted sizes for stoves for domestic use inevitably restrict the space available for, and positioning of, the burners and the chambers in the stove. They have to be close to one another but heat transfer between the chambers is reduced by the use of ceramic material in the chamber structures and may be further reduced by providing a separating air gap between the chambers and/or insulating, or heat soak, partitioning.

The cooker may comprise at least one oven and preferably two - a roasting oven and a warming oven.

It may also include a hob with one or more hot plates.

The or each oven may be defined by metal box structures having hinged access doors. If there is a roasting oven it is convenient for the roasting oven to be positioned above the warming oven. The roasting oven may be heated by passing products of combustion from the burners over part or all of one or more of the walls of the roasting oven. This may be achieved by leading those products of combustion through separate passages to a flue. These passages may be located such that the products of combustion pass over two or more of the walls of the roasting oven before reaching the flue. This arrangement enables more rapid and uniform heating of the roasting oven to be achieved than that previously attainable in stoves of this kind where the products of combustion have only been passed over one wall of the roasting oven.Heat for the warming oven may be provided by heat exchange from the roasting oven, for example by radiation, or through one or more heat exchange components extending from the roasting oven to the warming oven, or by passing products of combustion from the cooker burner over part or all of at least one wall of the warming oven.

The boiler may be in two or more connected segments around each of which the products of combustion are circulated to enhance the heating of water in the boiler. There may be baffles to extend the flow path of the products around the segments of the boiler. The segments may comprise a double walled tubular shell part defining a jacket through which the water is circulated and one or more tubular components surrounded by and communicating with the interior of the jacket for water to pass through as well.

When the burners are of the preferred pressure jet type it is desirable where possible for the separate passages which lead the products of combustion from the two burners to the flue to lead the products to the flue with gradual changes of direction so as to reduce sound resulting from the fast flowing gases impinging upon surfaces of the passages.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a front view of an oil-burning stove in accordance with the present invention; Figure 2 is a front view of the stove with doors removed; Figure 3 is a simplified vertical section through part of the stove; Figure 4 is an enlarged fragmentary section showing a boiler burner of the stove; Figure 5 is an enlarged perspective view of a burner firing chamber in the stove, and Figure 6 is an enlarged perspective view of a boiler included in the stove.

In this embodiment of the invention an oil-burning stove is provided for domestic use, being dimensioned to be compatible with standard floor standing kitchen unit furniture. The stove comprises a cast iron body 1 on a plinth 2 and having a hob 3 at standard work-surface height for kitchen furniture. Within the body 1 in one half of the stove are a warming oven 4 and a roasting oven 5 directly above the warming oven, each oven having a side hinged door 6,7 respectively, at the front of the stove. Housed in the lower part of the body 1 in the other half of the stove are two oil-fired burners 8,9 Figure 2, mounted to fire into respective chambers 10,11. In the upper part of the body in that half of the stove is a boiler 12. There is an opening 13 in the front of the stove opposite the two burners 8,9 and a further opening 14 opposite the boiler 12.Side hinged doors 15,16 respectively close the openings 13,14.

The two ovens 4,5 are conventional box structures made up of cast iron components secured and sealed together.

Hot plates, not shown, are included in the hob 3.

One burner 8, the cooker burner, serves the ovens 4,5 of the stove and the other burner 9, the boiler burner, serves the boiler 12. The chambers 10,11 into which the burners 8,9 fire extend horizontally side by side from front to back of the stove. The burners are mounted at the front ends of their respective chambers to fire horizontally into the chambers. Each burner is of a pressure jet type developed to operate on kerosene and having automatic ignition and thermostatic control. The two burners are independently controlled and can be turned on and off by the user as required. Nozzles of the burners extend just a short distance into the chambers so that the chambers are largely free for the burner flames and products of combustion to pass along.

Controls, not shown, for the burners are on a panel 17, Figure 2, mounted behind the opening 14 in front of the boiler 12. Access is readily gained to them by way of the door 15 at that opening. The controls could be at another conveniently accessible position at the side, front or top of the body, if desired.

The two chambers 10,11 are supported below the boiler 12 on brackets 18 fixed to the body 1, the chamber 10 being nearest to the ovens 4,5.

The chamber 10 into which the cooker burner 8 fires is essentially a unitary moulding of ceramic fibre material. It is of hollow tubular shape of generally square cross-section, as best seen in Figure 5, closed at its rearward end by an integral back wall 19. The forward end of the chamber is closed by a cast-iron closure plate 20, Figure 4, covered internally by an insulating layer 21 of ceramic material and fixed to the body 1. That closure plate 20 also closes the forward end of the chamber 11 into which the boiler burner 9 fires, and it is on the closure plate that the two burners are mounted by a fixing bolt 22. Along the topside corner of the chamber 10 nearest to the ovens there is a products outlet 23.The products outlet 23 opens into the lower end of a products passage 24, Figure 3, extending upwards alongside the roasting oven 5 and also between that oven and the warming oven and over the roasting oven, below the hob, to a flue 25 at the rear of the stove. An integral upstanding rib 26 extending centrally along the top of the chamber 10 from front to back locates under a part of the boiler, as shown in Figure 3. Next to the rib 26 an insulating shoe 27 of ceramic material is located in the products passage 24 against the boiler 12.

The ceramic material of the chamber 10, the rib 26 and insulating shoe 27 all serve to reduce transfer of heat to the boiler from the cooker burner flame and its products of combustion. Heat transfer from products of combustion from the cooker burner passing along the products passage 24 to the flue 25 heats the roasting oven and the warming oven 4.

Chamber 11 into which the boiler burner 9 fires is of box form compositely defined by metal plates 28 and an L-section component 29 moulded from ceramic fibre.

The limbs of the L-section component 29 form respectively a bottom wall 30 and a side wall 31 of the chamber 11, the side wall 31 being adjacent to the chamber 10. At its rearward end the chamber 11 is open for the products of combustion from the boiler burner to pass into a products passage, not shown, which leads the products to the boiler above the chambers.

The boiler 12 is a metal plate structure bolted to the body 1. As shown in Figure 6 it comprises a vertically extending rectangular hollow shell 32, open at top and bottom but having inner and outer walls 33,34 respectively which are sealed together at the top and bottom of the shell to define a water containing cavity 35 between them, and a pair of tubular components 36 extending parallel to one another across, and for a substantial part of the depth of, the inside of the shell 32. The tubular components 36 open through the inner walls 33 of the shell to communicate with the cavity 36. Supply and discharge pipe connections, not shown, are provided for the connection of pipes to supply water to the boiler to be heated and to take heated water away from the boiler. Water supplied to the boiler circulates round the cavity 35 in the shell 32 and through the tubular components 36.

Products of combustion from the boiler burner 9 passing out from the rear of the chamber 11 are directed by the associated products passage into the bottom of the hollow inside of the shell 32. The products rise up through the shell, around the tubular components 36 and then pass out of the top of the shell under the hob and are channelled to the flue 25. Water in the cavity 35 and in the tubular components 36 is thus heated by the products of combustion. Although not shown, baffles are preferably provided inside the shell around the tubular components to interrupt the flow of the products through the shell and so promote the heat transfer from the products to the boiler for enhanced efficiency of heating the water in the boiler.

Hot water supplied from the boiler may be used for central heating and for domestic hot water supply.

The hot plates of the hob are heated by the products of combustion of the cooker burner as they pass to the flue. Insulation, not shown, is provided at the underside of the hob around the hot plates to reduce heat transfer at the hob except at the hot plates.

The burners may be used together to heat the ovens and boiler at the same time, or they may be used separately for heating the ovens alone or the boiler alone, as required. By virtue of the insulation provided there is minimal heat transfer between the cooker and boiler functions of the stove and so close control of the heating requirements of the two functions can be maintained.

Claims (24)

1. An oil or gas-burning stove which comprises in combination a cooker and a boiler for hot water and which has oil or gas-fired burners for the cooker and boiler, the burners being individual, independently controllable and able to be turned on and off as required.

2. A stove according to Claim 1 wherein the burners are of a pressure jet type which have oil or gas and air supplied under pressure for combustion, and include automatic ignition means.

3. A stove according to Claim 1 or Claim 2 wherein each of the burners is thermostatically controlled and can be adjustably set for, and in, use by the user.

4. A stove according to any preceding claim wherein the burners fire into chambers formed at least in part of ceramic material.

5. A stove according to Claim 4 wherein at least one of the chambers is formed wholly, or for the most part, of ceramic material.

6. A stove according to Claim 5 wherein at least one of the chambers comprises a unitary tubular moulding of ceramic material.

7. A stove according to any one of Claims 4 to 6 wherein the chambers are separated from one another by an air gap to reduce heat transfer between the chambers.

8. A stove according to any of Claims 4 to 7 wherein insulating partitioning is provided between the chambers to reduce heat transfer between the chambers.

9. A stove according to any of Claims 4 to 8 wherein a heat soak is provided between the chambers to reduce heat transfer between them.

10. A stove according to any of Claims 4 to 9 wherein the burners are disposed substantially outside the chambers.

11. A stove according to any of Claims 4 to 10 wherein the chambers are disposed side-by-side and are closed at one end by a common insulated closure plate on which the burners are mounted.

12. A stove according to any preceding claim wherein the cooker comprises at least one oven.

13. A stove according to Claim 12 wherein the cooker comprises a roasting oven and a warming oven.

14. A stove according to Claim 12 or Claim 13 wherein the or each oven comprises a metal box structure having an access door.

15, A stove according to any of Claims 12 to 14 wherein the oven, or at least one of the ovens, is heated by products of combustion from one of the burners passed over at least part of one or more of the walls of the oven.

16. A stove according to Claim 15 wherein products of combustion from the burners are directed through separate passages to a flue, the passages from said one burner being located such that the products of combustion from said burner pass over two or more walls of the oven, or of at least one of the ovens, before reaching the flue.

17. A stove according to either one of Claims 15 and 16 as dependent from Claim 13 wherein the roasting oven is heated by products of combustion from said burner, and the warming oven is heated by heat exchange from the roasting oven.

18. A stove according to any preceding claim wherein the cooker includes a hob with one or more hot plates heated by products of combustion from at least one of the burners.

19. A stove according to any preceding claim wherein the boiler comprises a plurality of connected segments around each of which products of combustion from one of the burners are circulated.

20. A stove according to Claim 19 wherein baffles are provided which extend the flow path of the products of combustion around the segments of the boiler.

21. A stove according the Claim 19 or Claim 20 wherein each segment comprises a double-walled tubular steel part defining a jacket through which water is caused to be circulated when the stove is fitted for use, and one or more tubular components surrounded by and communicating with the interior of the jacket for water to pass through as well.

22. A stove according to any preceding claim wherein the burners for the cooker and the boiler are positioned below the boiler.

23. A stove according to any preceding claim wherein controls for the burners are mounted at an opening at the front of the stove closed by an access door.

24. An oil-burning stove substantially as described herein with reference to the accompanying drawings.