GB2495506A

GB2495506A - Cooking and heating stove with heat resistant walls

Info

Publication number: GB2495506A
Application number: GB201117528A
Authority: GB
Inventors: Michael Graham Reid
Original assignee: ALSITEK Ltd
Current assignee: ALSITEK Ltd
Priority date: 2011-10-11
Filing date: 2011-10-11
Publication date: 2013-04-17
Also published as: WO2013054095A1; GB201407557D0; GB201117528D0; GB2511659B; GB2511659A

Abstract

A cooking and heating stove has cast heat resistant walls, a combustion chamber 15, and a cooking surface 11 above the chamber 15. The stove is mainly mineral polymer (e.g. made by adding alkaline solution to a calcined aluminosilicate) for rapid deployment to a disaster area. The stove is constructed in situ by fabricating a frame structure including an outer shell 1 and liner 3 for temporary support (e.g. from cardboard); and casting a mineral polymer foam into voids in the frame to become solid heat resistant walls. Once the foam has set a fire lit in combustion chamber 15 burns away the temporary combustible frame leaving mineral polymer walls. The stove also has a flue 4,8, exhaust 10 and damper 14, and the cooking surface 11 is steel.

Description

A COOKING APPARATUS ND METHOD FOR MAKING SAME

The present invention relates to a oooking apparatus and method of making same, particularly as a means of providing a low cost efficient stove for disaster relief and reducing fuel poverty. The invention also extends to use as an apparatus for heating in similar situations.

BACKGROUND TO THE INVENTION

It is an unfortunate reality that immediately after a disaster such as a flood or an earthquake there are often no easy means for providing water boiling or cooking facilities.

In many situations simple stone circle fires are used to cook upon, however, these use a lot of wood or other fuel such as coal or refuse. This solution is ineffioient for cooking and usually results in fuel poverty and pollution from insufficiently burnt fuel.

The need for simple but efficient cooking/heating facilities is not only limited to natural disasters. For example those who live, ordinarily, cooking on rings of stones or inefficient s.toves also need improved faci utica, e.g. in Kenya where deforestation has resulted from inoffioient means for cooking; and Mongolia in the s1anties of Ulanhaataar where the smog from ineffioient heatino stoves is a health and economic disaster.

SUMMARY OF THE INVENTION

The present invention seeks to propose a cooking apparatus and method of making same that provides an efficient stove at low cost, able to be rapidly deployed.

In one broad aspect according to the invention there is provided a cooking apparatus including walls made of mineral polymer, a cooking surface and a chamber for receiving a source of heat or fuel.

It should be noted that "cooking apparatus" could also be more broadly defined as "an apparatus for cooking and/or heating" within the scope of the invention.

Preferably the mineral polymer is in a foamed form. Such materials are known to be low cost, low embodied energy fireproof insulating materials. The cooking apparatus of the invention describes a stove made largely from mineral polymer foam thus containing the heat within the stove and delivering the heat to a hot plate or the like where it is needed and burning the fuel efficiently. As a result, less fuel is needed for cooking.

One embodiment of the invention is produced by casting mineral foam in a cardboard container within which the combustion gas path is described by a series of cardboard tubes. Once cast and set, the mineral polymer comprises the body of the stove and the combustion process consumes the tubular cardboard formers.

Therefore, according to a second broad aspect the invention provides a method of fabricating a cooking apparatus including the steps of: providing an outer shell; inserting a chamber liner to form a chamber within the shell; locating a cooking surface above the chamber liner; and casting a heat resistant material into the shell to surround the chamber liner.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a cooking apparatus and method of construction according to the invention, in the form of a stove; Figure 2 illustrates a general view of a cooking apparatus according to the invention; Figures 3a and 3b illustrate side and frontal views respectively of the cooking apparatus from Figure 2.

Figure 1 shows the main elements for constructing a cooking apparatus according to the invention. For example, a cardboard box 1 or outer shell is supplied, packed thereinto, with all of the components needed to produce a stove for rapid deployment. A precast block 2, preferably made from mineral polymer foam, is placed at the bottom of the box to serve as a support for a cardboard combustion chamber liner or former 3 placed thereon and taped to box 1 to seal the joint. Cardboard flue means in the form of tube 4 is taped similarly over hole 5 in former 3. Taped to a vertical side of tube 4 is a smaller tube 6 which is also sealed with tape to box 1. A seoond block 7, also preferably of mineral polymer foam, is placed upon chamber liner 3 to serve as a support for a further tube B that is then sealed to tube 4 with tape. A (generally hollow) saddle piece 9 is sealed atop tube 8 to serve as a support for a steel hot plate 11 placed thereon. Finally, a light gauge steel tube 10 is sealed with tape to tube 8 to act as a chimney or exhaust means.

It should be noted that the example of "cardboard" referred to herein merely represents a convenient and generally combustible material that can provide a frame or temporary structural support. It could be interchangeable with another suitable material, e.g. paperboard or even thin particle board/plywood, as a replacement.

As background to the invention, mineral foam is made by adding an alkaline solution to a caloined aluminosilicate powder and a foaming agent. A suitable mineral polymer that will meet the reguirements of the invention is EcoFoam F35, produced by EcoFoam Limited. The unset foam is poured into void spaces 12 within the main shell formed by the cardboard structure and allowed to set up to level 13.

By way of example, the foam is added in layers of approximately 70mm and each layer takes 3ominutes to cure at 35°C up to 8 hours at 2000. The formulation can be modified dependent on the ambient temperature. Furthermore, different formulations would allow different thicknesses of layer to be cast. In general the assembly kit is intended so that the solid raw materials come In one-layer bags which means the user does not have to measure out the materials.

Once the foam has set solid a fire is lit with suitable fuel placed in the combustion chanter 15 formed by liner 3 and the combustion products are drawn through tubes 4, 8 and 10 by convection. As the fire develops the combustible chamber liner 3 burns away exposing foamed mineral walls. Similarly tubes 4, 6, 9 and 8 burn away, exposing the underside of hot plate 11 to hot combustion gases, while the exhaust tube 10 remains functionally in place since, preferably, it is not combustible.

The stove can be used immediately and there are usable temperatures on the hotplate within 10 minutes of lighting the stove for the first time.

A loose fitting damper 14 is inserted into an aperture/hole formed through a mineral polymer side wall of the cooking apparatus produced by the burning of tube 6 and, locally, box 1. The damper itself may also be made of mineral polymer.

Air may pass by damper 14 in small quantities sufficient to burn any partially burnt combustion gases not completely oxidised in chamber 15.

If the combustion process in chamber 15 needs to be slowed then damper 14 may be adjusted accordingly. A taper 16 is provided on damper 14 making it a wedge shape. Therefore, the amount of air allowed to enter past the damper may be adjusted by the degree to which it is withdrawn. By this means, the rate of combustion in chamber 15 can be controlled and thus the rate of fuel use and the temperature of hot plate 11 and, hence, the rate of cooking of any food item placed on the hot plate can also be controlled.

Advantageously, the insulating effect of the mineral polymer causes an elevation of the temperature in chamber 15 when compared to open fires or uninsulated stoves. This high temperature reduces the amount of polluting gases emitted by the stove and thus many of the negative health effects caused by pollution from open fires and inefficient cooking devices.

It can be recognised that the layout of the stoves illustrated in Figures 1 and 2/3 is different in that the combustion chamber 15 can have its opening at the "front" (as in Figure 2) or "back" (Figure 1) of the stove as defined by the location of the cooking surface ii which will generally be situated convenient for a user. For safety, the configuration of Figure 1 is probably preferable because the open fire is behind the stove and the damper means 14 is readily accessible.

In a further embodiment of the stove, the mineral polymer filled space 12 may be additionally thick thus reducing tc near ambient temperature the exterior of the stove. Such an embodiment would be suitable used in hot climates where the sole purpose of the stove is cooking (and not external heating) thus further reducing fuel use and improving the comfort of the user.

Yet another embodiment of the invention may include a heat exchange element in place of the flue means, thus providing further heating in cold climates without reducing the combustion temperature and thus maintaining the polluting effects at a low level.

It should be appreciated that a mineral polymer foam, while preferred, may be superseded by another suitable heat resistant material that can be cast into the cardboard framework according to method of construction of the apparatus.

A cooking apparatus, with all components packed in a cardboard outer shell ready for assembly, can be rapidly deployed with portability where needed and can achieve relatively low cost and weight.

Claims

<claim-text>What We Claim Is: 1. A cooking apparatus including walls made of mineral polymer, a cooking surface and a chamber for receiving a source of heat or fuel.</claim-text> <claim-text>2. The cooking apparatus of claim 1 wherein the mineral polymer is foamed.</claim-text> <claim-text>3. The cooking apparatus of either claim 1 or 2 wherein there is a flue means in communication with the chamber.</claim-text> <claim-text>4. The cooking apparatus of claim 3 wherein there is an exhaust means in communication with the flue means.</claim-text> <claim-text>5. The cooking apparatus of claim 4 wherein the exhaust means is a tube of non-combustible material extending upwards from a mineral polymer wall of the cooking apparatus.</claim-text> <claim-text>6. The cooking apparatus of any of claims 3 to 5 further including an external aperture communicating with the flue means or chamber.</claim-text> <claim-text>7. The cooking apparatus of claim 6 wherein the aperture receives a damper means.</claim-text> <claim-text>8. The cooking apparatus of claim 7 wherein the damper means is a wedge-shaped element.</claim-text> <claim-text>9. A method of fabricating a cooking apparatus including the steps of: providing an outer shell; inserting a chamber liner to form a chamber within the shell; locating a cooking surface above the chamber liner; and casting a heat resistant material into the shell to surround the chamber liner.</claim-text> <claim-text>10. The method of claim 9 including a further step, prior to casting, of inserting a flue liner to form a flue means adjacent the chamber liner.</claim-text> <claim-text>11. The method of claim 10 including a further step, prior to casting, of inserting a non-flammable tube into communication with the flue liner.</claim-text> <claim-text>12. The method of claims 9, 10 or 11 wherein a cavity forming element is located between the outer shell and chamber liner or flue liner.</claim-text> <claim-text>13. The method of any of preceding claims 9 to 12 wherein the chamber liner is supported by a block element in order to distance it from the outer shell.</claim-text> <claim-text>14. The method of claim 10 wherein the flue liner is supported by a block element located between the flue liner and chamber liner.</claim-text> <claim-text>15. The method of any of preceding claims 9 to 14 wherein, after casting, fuel is placed within the chamber and a fire set.</claim-text> <claim-text>16. The method of any of preceding claims 9 to 15 wherein the heat resistant material is a mineral polymer.</claim-text> <claim-text>17. The method of claim 16 wherein the mineral polymer is poured into the shell as a foam.</claim-text> <claim-text>18. The method of any of preceding claims 9 to 17 wherein the outer shell and chamber liner are constructed of either cardboard, paperboard, plywood or particle board or equivalent materials.</claim-text> <claim-text>19. A cooking apparatus substantially as herein described with reference to the accompanying drawings.</claim-text> <claim-text>20.A method of fabricating a cooking apparatus substantially as herein described with reference to the accompanying drawings.</claim-text>