GB2300475A - Heat accumulating stove - Google Patents

Abstract

A heat accumulating stove having at least one oven (18, 20) above a heating chamber (16) from which hot gases exit to pass through passages (26) formed within the metal walls of the oven or ovens in order to heat the oven or ovens, which are enclosed by insulation (38, 40) on the outside of the walls.

Description

Heat Accumulating Stove This invention relates to a heat accumulating stove of the kind having a metallic heat accumulator and a heating chamber burning wood, coal, oil or gas, or consuming off-peak electricity.

According to the invention, a heat accumulating stove has at least one oven with metallic walls, and the oven is heated by hot gases (including air) from the heating chamber which are directed through one or more passages formed within one or more of the walls of the at least one oven.

In the prior art, the hot gases from the heating chamber in a heat accumulating stove are directed past the outside of the metallic walls of one or more ovens to be heated. The gases thereby pass from a space or void below the oven through relatively wide spaces to the sides of the oven to a space or void above the oven.

The spaces or voids in question are bounded by sharp corners and regions at which the gases are caused to change direction of flow relatively abruptly. The resulting flow of gases is thus relatively turhulent, creating a characteristic undesirable "roaring" noise when a stove with oil or gas, air blown burners is in use.

The present invention aims to overcome this problem by providing a more controlled flow of the hot gases such that turbulence is minimised.

Preferably, the hot gases flow through a plurality of passages formed within one or each of the side walls of the at least one oven.

The heating chamber is preferably enclosed and has a hot gas exit from which a manifold arrangement extends and splits into a plurality of hot gas inlets connected to the passage in the wall or walls of the at least one oven.

Above the oven, an analogous manifold arrangement may collect the hot gases exiting from the passage and feed said gases to one or more channels in the underside of a hot plate located above the oven.

The hot gases may then exit from the hot plate channel or channels to a plenum chamber to be connected to a flue.

Preferably, the at least one oven is thermally insulated. The manifold arrangement or arrangements are preferably also thermally insulated. The stove is thus thermally more efficient than stoves known hitherto, which primarily rely on thermal insulation around the exterior walls.

A preferred stove has at least two ovens side by side above the level of the heating chamber. In this preferred stove, four manifold arrangements are provided to feed hot gases from the heating chamber to passages in each of the side walls of the two ovens, but clearly two more complex manifold arrangements could be provided, for example, one for each oven. Two hot plates are preferably provided, one above each oven, associated manifold arrangements being provided to feed gases to channels in the undersides of these hot plates from the exits of the passages in the side walls of the oven. Throttling means for the hot gas flows, of any suitable kind, may be provided such that one oven in use operates at a higher temperature than the other.

Additionally, a low temperature oven may be provided to the side of the heating chamber, primarily heated by conduction and convection from the oven above it, although a gas passage fed through one or more manifold arrangements could also be provided for this oven.

A heat accumulating stove in accordance with the invention is now described by way of example with reference to the accompanying drawings, in which: Figure 1 shows the stove diagrammatically in transverse cross-sectional view taken inside the front wall; Figure 2 is a diagrammatic cross-sectional view at right angles to the crosssection of Figure 1; and Figure 3 shows the underside of a hot plate.

Referring to Figures 1 and 2, the illustrated heat accumulating stove comprises a relatively thick-walled metallic housing 10 capable of acting as a heat sink, lined within an outer skin 14 with thermal insulation 12 to reduce heat loss. Reference 12A denotes ceramic material also forming part of the insulation.

The housing 10 accommodates a fire box (or heat storage chamber operating on off-peak electricity) and three ovens. The fire box 16, for example burning gas or oil or a solid fuel such as wood or coal, is located to one side at the bottom of the housing 10. Above the fire box 16 is provided a roasting oven 18, typically in use maintained at about 400 to 450 degrees F, whilst to one side of the roasting oven on the same level is provided a baking oven 20, typically in use maintained at about 300 to 350 degrees F.

The ovens 18 and 20 are heated by hot gases drawn from the fire box 16 towards a flue by natural or forced draught. In accordance with the invention, these hot gases exit the fire box 16 into manifolds 22, 22A, 24, 24A through which the hot gases are directed into passages 26 formed within the two side walls of each oven 18, 20. As will be clear from Figure 2, which shows the near wall of the roasting oven 18 in side view, four vertical passages 26 may be provided within each oven side wall, the manifold 22 (and likewise the other manifolds), splitting into four spurs connecting to the individual passages.

Ahove the ovens 18, 20, two hot plates 28, 30 are formed with underside channels 32 (see also Figure 3) which receive the still hot but cooler gases exiting from the top of the passages 26. Manifolds 34, 34A, 36, 36A serve to direct the hot gases from the exits of the passages to the leading ends of the channels 32, the exit ends of which lead into a plenum chamber (not shown) having a restricted or throttled outlet to a flue box.

Whereas conventionally the hot gases are directed through the voids and spaces around and between the ovens in order to heat the ovens, in the present arrangement the ovens are thermally insulated externally, as indicated at 38 and 40. Moreover, the manifold arrangements employed are most preferably of metallic pipework with coated thermal insulation. Thus, the heat from the hot gases emanating from the fire box 16 is much more efficiently utilised than in the prior art stoves. Moreover, minimisation of turbulence in the gas flows reduces the noise levels of the stove.

Conveniently, below the baking oven 20 is provided a simmering oven 42. This oven 42 could also be heated by a throttled flow of hot gases, but in the present invention it is preferably heated, to a temperature of about 200 to 250 degrees F, by heat conduction and convection from the baking oven 20. Thermal insulation is thus omitted at the underside of the baking oven and the top of the simmering oven.

The illustrated arrangement is capable of modification in a number of ways within the scope of the invention hereinbefore defined. in particular, various geometrically different manifold arrangements, which may incorporate throttling means or the like for temperature control, may be employed in place of the illustrated arrangements, for example to suit ovens having walls incorporating different arrangements of passages for the flow of hot gases.

Claims (14)

Claims

1. A heat accumulating stove which has at least one oven with metallic walls, and the or each oven is heated hy hot gases (including air) from a heating chamber which are directed through one or more passages formed within one or more of the walls of the at least one oven.

2. A stove according to claim 1, wherein the hot gases flow through a plurality of passages formed within one or each of the side walls of the at least one oven.

3. A stove according to claim 1 or claim 2, wherein the heating chamber is enclosed and has a hot gas exit from which a manifold arrangement extends and splits into a plurality of hot gas inlets connected to the passage or at least one of the passages in the wall or walls of the at least one oven.

4. A stove according to claim 3, wherein, above the oven, a manifold arrangement collects the hot gases exiting from the passage or at least one of the passages and feeds said gases to one or more channels in the underside of a hot plate located above the oven or above at least one oven.

5. A stove according to claim 4, wherein the hot gases exit from the hot plate channel or channels to a plenum chamber to he connected to a flue.

6. A stove according to any of claims 1 to 5, wherein the at least one oven is thermally insulated.

7. A stove according to claim 6, wherein the manifold arrangement or arrangements are also thermally insulated.

8. A stove according to any of claims ] to 7, having at least two ovens side by side above the level of the heating chamber.

9. A stove according to claim 8, wherein four manifold arrangements are provided to feed hot gases from the heating chamber to passages in each of the side walls of the two ovens.

10. A stove according to claim 9, wherein two hot plates are provided, one above each oven, associated manifold arrangements being provided to feed gases to channels in the undersides of these hot plates from the exits of the passages in the side walls of the oven.

11. A stove according to any of claims 8 to 10, wherein throttling means for the hot gas flows are provided such that one oven in use operates at a higher temperature than the other.

12. A stove according to any of claims 8 to 11, wherein a low temperature oven is provided to the side of the heating chamber, heated at least in part hy conduction and convection from the oven above it.

13. A stove according to claim 12, wherein a gas passage fed through one or more manifold arrangements is also provided for the low temperature oven.

14. A heat accumulating stove substantially as hereinhefore described with reference to the accompanying drawings.