WO2013054095A1

WO2013054095A1 - A cooking apparatus and method for making same

Info

Publication number: WO2013054095A1
Application number: PCT/GB2012/052479
Authority: WO
Inventors: Michael Graham Reid
Original assignee: Alsitek Limited
Priority date: 2011-10-11
Filing date: 2012-10-05
Publication date: 2013-04-18
Also published as: GB201117528D0; GB2511659A; GB201407557D0; GB2511659B; GB2495506A

Abstract

A cooking apparatus in the form of a stove substantially made from mineral polymer for the purposes of rapid deployment to a disaster area. Preferably the cooking apparatus is constructed in situ by fabricating a frame structure, including an outer shell (1) from combustible materials, e.g. cardboard. Thereafter a mineral polymer foam is cast into voids of the frame to become solid heat resistant walls. When the foam is set a fire is lit in a combustion chamber (15) and the combustible walls of the cooking apparatus burn away, leaving a mineral polymer wall. The cooking apparatus further includes a cooking surface (11), flue means (4,8), exhaust (10) and damper means (14). In another form the apparatus may be utilised as a heating apparatus.

Description

A COOKING APPARATUS AND METHOD FOR MAKING SAME

TECHNICAL FIELD The present invention relates to a cooking 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 inefficient 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 stoves also need improved facilities, e.g. in Kenya where deforestation has resulted from inefficient means for cooking; and Mongolia in the shanties of Ulanbaataar where the smog from inefficient heating stoves is a health and economic disaster. DISCLOSURE 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 which is 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.

A mineral polymer is a polymeric material created by the dissolution of certain solid inorganic minerals by acid or base reaction and the re-forming of the resulting solution to produce a polymeric solid. For example, certain aluminosilicates can be dissolved by the action of a strong base and the molecules in solution polymerise into long chain or cross linked polymeric macro-molecules characterised by covalent bonding. Other terminology for this kind of material includes geopolymers, alkali activated polymers, inorganic polymers, etc.

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.

Just like oil-based polymers, mineral polymers consist of long chain or cross-linked chains of atoms. The difference is that the atoms are not carbon but aluminium and silicon; the raw materials are not oils but alumina (aluminium oxide} and. silica (silicon oxide) based minerals that are commonly available worldwide. Like the oils, the minerals are processed to make feedstock for the various types of mineral polymers .

One embodiment of the invention is produced by casting mineral foam in a cardboard (i.e. flammable) 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 .

The method of the invention effectively requires the construction of a frame structure made up from the outer shell, chamber liner and, optionally, additional components. In practice the components may be supplied as a kit of parts, e.g. in a box which also acts as the outer shell. Preferably the heat resistant material cast into the frame structure is a mineral polymer (foam) .

In the case of a heating only apparatus it would be possible to omit the cooking surface entirely or, optionally, substitute this for a heat radiating/transfer surface more suited for a heating apparatus. Indeed the cooking surface itself can more broadly be interpreted as a transfer means for distributing the heat inside the apparatus to the outside, either for heating the air or a cooking apparatus such as a pan. In one form of the heating apparatus the heat transfer surface may be side/outward facing.

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; and

Figure 4 illustrates a block utilised as a door for the cooking apparatus.

MODE ( S ) FOR CARRYING OUT THE INVENTION

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 or other heat resistant material, 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 abutting joining surfaces. 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 second heat resistant block 7, also preferably of mineral polymer foam, is placed upon chamber liner 3 to serve as a support for a further tube 8 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. Notably, hot plate 11 is placed on the saddle piece 9 with its edges overhanging (which will later be supported by a ledge of solid mineral foam) . Finally, a light gauge steel tube 10 is sealed with tape to tube 8 to act as a chimney or exhaust means. This tube could be substituted for another suitable material or means, e.g. a pipework that directs exhaust out of a building etc.

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 thin particle board/plywood, as a replacement.

As background to the invention, mineral foam is made by adding an alkaline solution to a calcined aluminosilicate powder and a foaming agent. A suitable mineral polymer that will meet the requirements of the invention is EcoFoam F35, produced by EcoFoam Limited, or its later equivalent A-l from Alsitek 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 that is approximately flush with the hot plate 11 and effectively forming a support ledge therefor. A mineral foam formulated for faster setting properties is preferable.

By way of example, the foam is added in layers of approximately 70mm and each layer takes 30minutes to cure at 35°C up to 8 hours at 20°C. 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 chamber 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 11 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. Figure 4 illustrates a block 17, preferably made from mineral polymer or like heat resistant material, that can be utilised as a "door" in the entrance of the combustion chamber. It was found that, by restricting incoming air, it was possible to both increase the internal temperature and reduce fuel consumption .

The addition of a vee-groove 18 to the block 17 allows adjustment of the air flow into the combustion chamber 15 (similar to the taper on the damper means) and thus optimisation of the temperature. In testing it was found that the temperature can reach as high as 1200°C with this feature incporated. The widest part of the groove 18 should face into the chamber with air flow being restricted by the narrowing vee as the block 17 is pushed into the chamber.

In a further embodiment of the stove, the mineral polymer filled space 12 may be additionally thick thus reducing to 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. Another method of reducing the external surface touch temperature of the stove is to provide the shell 1 in a non-combustible, insulating material

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. INDUSTRIAL APPLICABILITY 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 the 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. The apparatus can be assembled with relatively slow skill and simple instructions for use.

Claims

CLAIMS :

1. A method for fabricating a cooking and/or heating apparatus including the steps of :

providing an outer shell;

inserting a chamber liner to form a chamber within the shell;

locating a cooking or heat transfer surface above or adjacent the chamber liner; and

casting a heat resistant material into the shell to surround the chamber liner.

2. The method of claim 1 wherein the heat resistant material is a mineral polymer.

3. The method of claim 2 wherein the mineral polymer, once set, is in the form of a foam.

4. The method of any one of the preceding claims including a further step, prior to casting, of inserting a flue liner to form a flue means adjacent and/or above the chamber liner.

5. The method of any one of the preceding claims including a further step, prior to casting, of inserting a non-flammable tube into communication with the flue liner.

6. The method of any one of the preceding claims wherein a cavity forming element is located between the outer shell and chamber liner or flue liner.

7. The method of any of the preceding claims wherein the chamber liner is supported by a support element in order to distance it from the outer shell.

8. The method of claim 4 wherein the flue liner is supported by a support element located between the flue liner and chamber liner.

9. The method of any of the preceding claims wherein, after casting, fuel is placed within the chamber and a fire set.

10. The method of any of the preceding claims wherein either or both of the outer shell and chamber liner are constructed of either cardboard, paperboard, plywood or particle board or equivalent combustible materials.

11. The method of any of the preceding claims wherein the cooking surface is located upon a support piece above the chamber liner.

12. The method of claim 11 wherein the support piece is a combustible saddle.

13. A cooking or heating apparatus obtainable by the method of any one of claims 1 to 12.

14. A kit of parts for fabricating a cooking and/or heating apparatus including:

an outer shell;

a chamber liner to form a chamber within the shell; a cooking surface; and raw materials for casting a heat resistant material into the shell to surround the chamber liner.

15. The kit of parts of claim 14 wherein the outer shell is a box within which the other components are transported .

16. The kit of parts of claim 14 or 15, further including a set of instructions based on the method of any one of claims 9 to 18.

17. A cooking apparatus including walls made of mineral polymer, a cooking surface and a chamber for receiving a source of heat or fuel.

18. The cooking apparatus of claim 17 wherein the mineral polymer is foamed.

19. The cooking apparatus of either claim 17 or 18 wherein there is a flue means in communication with the chamber .

20. The cooking apparatus of claim 19 wherein there is an exhaust means in communication with the flue means.

21. The cooking apparatus of claim 20 wherein the exhaust means is a tube of non-combustible material extending upwards from a mineral polymer wall of the cooking apparatus.

22. The cooking apparatus of any of claims 19 to 21 further including an external aperture communicating with the flue means or chamber.

23. The cooking apparatus of claim 22 wherein the aperture receives a damper means.

24. The cooking apparatus of claim 23 wherein the damper means is a wedge-shaped element.