GB2486184A

GB2486184A - Solid fuel cooker with secondary combustion and catalyst

Info

Publication number: GB2486184A
Application number: GB1020515.1A
Authority: GB
Inventors: Malcolm Craig Nutter
Original assignee: ESSE ENGINEERING Ltd
Current assignee: ESSE ENGINEERING Ltd
Priority date: 2010-12-03
Filing date: 2010-12-03
Publication date: 2012-06-13
Anticipated expiration: 2030-12-03
Also published as: GB2486184B; GB201020515D0

Abstract

A cooking and/or heating device 10 has a combustion section 12 for allowing combustion of solid fuel for heating a hot plate 16 and an oven 20a, 20b of the device 10, with a secondary combustor 14 of steel mesh downstream of the combustion section 12 and a catalytic combustor 17. The ovens 20a, 20b can vent cooking odours into the combustion gases, and the device can vent to a room. A manually operated bypass 35 diverts smoke around catalytic combustor 17 after refuelling.

Description

Solid Fuel Cooker This invention relates to a cooking and/or heating device, particularly, but not limited to, a cooking/heating device powered by solid fuel.

Existing cooking/heating devices have been designed based on a heat storage principal, in which fuel is combusted in a combustion section to maintain hotplates and ovens of the cooking/heating device at a working temperature. Disadvantages arise with this type of device in that fuel consumption can be undesirably high, because a temperature of the device is 1 0 maintained throughout a 24 hour period. This causes substantial exhaust emissions which can harm the environment. In certain countries new legislation exists to limit the emission of these devices to a level that conventional cooking/heating devices of this nature cannot comply with.

In particular, new limits of 2g/kg and under of particle emissions have been introduced in combination with minimum efficiencies of 65%. These limits are effectively stopping any usage of such cooking/heating devices, and since no existing devices can yet reduce emissions to the new limits, some markets remain elusive to manufacturers.

It is an object of the present invention to address the above mentioned disadvantages.

According to an aspect of the present invention there is provided a cooking/heating device, the device having at least one combustion section for allowing combustion of solid fuel for heating the device, the combustion section being operable to heat a hot plate of the device and at least one oven of the device, wherein the cooking/heating device further comprises a secondary combustor located downstream of the combustion section and a catalytic combustor downstream of the secondary corn bustor.

Downstream refers to a direction of flow of the combustion gases, i.e. the combustion section is upstream and in use issues combustion gases in a downstream direction.

The combustion section may be a wood or coal combustion section, most preferably a wood combustion section.

The one or more burners may be operable to heat an underside of the hot plate.

The secondary combustor is preferably adapted to be heated by the combustion section. The secondary combustor is preferably a mesh. Even more preferably the secondary combustor is made of steel.

The combustion section may be operable to heat an exterior of the at least one oven. The heat source for the at least one oven is preferably external to a cavity of the oven.

The at least one oven may be adapted to vent at least some odours/gases/vapours from the oven into an exhaust duct.

Said exhaust duct may contain within it the catalytic combustor. Preferably the catalytic combustor is operable to extract harmful odours/gases/vapours from the combustion process before release into the atmosphere, and acts as a filter to reduce tar build up within the flueway. Preferably the catalytic combustor is operable to acts together with the secondary combustor to reduce emissions of the cooking/heating device and increase the efficiency of the device. More preferably the catalytic combustor acts together with the secondary combustor to reduce emissions of the cooking/heating device to 2g/kg. Most preferably the catalytic combustor acts together with the secondary combustor to reduce emissions of the cooking/heating device to below 2g/kg.

The position of said catalytic combustor maintains the ideal working temperature of the catalyst and allows it to be protected from the direct flame of the combustion section whilst allowing easy access for maintenance.

The exhaust duct may incorporate a diverter, which may be operable to divert gases around the catalytic combustor. The diverter may be manually actuable. Preferably, the diverter is adapted to be opened to prevent exhaust gases from passing through the catalytic combustor and closed to allow exhaust gases to pass through the catalytic combustor.

The combustion section is preferably provided with a control to vary heat output and thus temperature of the respective hotplate and at least one oven.

Preferably a first duct is provided to channel combustion gases and heated air to the hotplate.

Preferably a second duct is provided to channel combustion gases and heated air around the at least one oven.

Insulation may be provided inside exterior walls of the device.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a schematic cross-sectional front view of a cooking/heating device having for simplicity one burner.

Figure 2 is a schematic plan view of the device of Figure 1 Figure 3 is a schematic front view of the device shown in figure 1.

Figure 1 shows a cooking/heating device 10 having a solid fuel burner 12 and insulator material 11 around its exterior walls.

The solid fuel burner 12 is arranged to heat a hotplate 16 by channelling combustion gases and heat from the burner 12 through a duct 13 to an underside of the hotplate 16. The combustion gases and heated air are then channelled along the length of the hotplate 16, from left to right as shown in Figure 1. From there, the exhaust gases are channelled to an output flue 18 at a rear part of the device 10.. The device may vent into a room in which it is located; in a similar way to a conventional gas oven.

Above the solid fuel burner 12 is located a secondary combustor 14 preferably made of steel and preferably formed in a mesh configuration. The secondary combustor 14 is arranged so that the burner 12 may heat it and cause further combustion of the fuel to thereby increase the efficiency of the device 10. The secondary combustor 14 also prevents flames from the material burning in the burner 12 from passing beyond the secondary combustor 14 towards a catalytic combustor 17 described below.

The solid fuel burner 12 is also arranged to heat upper and lower ovens 20a and 20b respectively. From the solid fuel burner, combustion gases and heated air are channelled from duct 13 to duct 15 down the right side of the upper and lower ovens 20a, 20b, across the top of the lower oven 20b in a circular manner, then the combustion gases and hot air are channelled to a rear of the upper and lower ovens 20a, 20b and to the output flue 18.

The upper and lower ovens 20a and 20b are arranged to vent cooking odours into the combustions gases to be channelled to the output flue 18.

The output flue 18 contains a catalytic combustor 17 that filters harmful chemicals from the combustion gases before release into the atmosphere or before release through the vent 19 into a room in which device 10 is located. The catalytic combustor 17 benefits from the presence of the secondary combustor 14, because flames are stopped from passing the secondary combustor 14, which flames would otherwise damage the catalytic combustor 17.

There is a also a manually operated bypass duct 35 that diverts flue gases around the catalytic combustor 17. A user operates a manual bypass lever 36 to close off the catalytic combustor 17 to allow the gases to bypass it to get to the flue 18. The bypass duct 35 is used when a user has refuelled the burner 12 and there is excessive smoke, which may damage the catalytic combustor 17. When the refuelled burner 12 is burning more efficiently the user can close the bypass duct 35 to allow the catalytic combustor 17 to clean the gases from the burner 12.

The solid fuel burner 12 has a fuel supply (not shown) placed in the bottom left hand compartment 28 according to usual design. The solid fuel may be wood or coal. Preferably, the solid fuel is wood to allow the catalytic converter to operate at maximum efficiency.

The solid fuel burner 12 is controlled by a flue control (not shown) in the usual manner.

The upper and lower ovens 20a, 20b are shown with respective doors 30a, 30b, compartment 29 is shown as an external access to the secondary combustor 14 for maintenance.

The cooking/heating device disclosed herein does not require the device to be maintained at a constant working temperature. Instead, a user can put fuel in the burner when required for cooking to reduce an amount of fuel that the device uses. Given the change in functionality, materials for the hotplate 16 and for walls of the upper/lower ovens 20a,b can be chosen to allow rapid conduction of heat to allow rapid heating when the burner 12 is ignited. They may be thinner materials. Lids 31 may optionally be provided on the hotplate. They may be provided for aesthetic reasons, rather than the practical reason of reducing heat flux from the device 10.

The configuration of said secondary combustor 14 and said catalytic combustor 17 within the device 10 allows combustion gases to be fully combusted then further filtered and therefore vastly reduces the exhaust emissions of the device as compared to existing devices. This has the benefits of reducing harmful gaseous products released into the environment and increasing the efficiency of fuel usage. In the current format as detailed above the device 10 consistently produces less than 2g/kg of particle emissions, and is therefore marketable in lower limit states.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims 1. A device for cooking/heating, having at least one combustion section for allowing combustion of solid fuel for heating the device, the combustion section being operable to heat a hot plate of the device and at least one oven of the device, wherein; the cooking/heating device further comprises a secondary combustor located downstream of the combustion section and a catalytic combustor downstream of the secondary combustor.
2. The device as claimed in claim 1, wherein the combustion section is a wood or coal combustion section.
3. The device as claimed in claims 1 and 2 wherein the combustion section is a
4. The device as claimed in any preceding claim wherein at least one combustion section is operable to heat an underside of the hot plate.
5. The device as claimed in any preceding claim wherein the secondary combustor is adapted to be heated by the combustion section.
6. The device as claimed in any preceding claim wherein the secondary combustor is a mesh.
7. The device as claimed in any preceding claim wherein the secondary combustor is made of steel.
8. The device as claimed in any preceding claim wherein the combustion section is operable to heat an exterior of the at least one oven.
9. The device as claimed in any preceding claim wherein the heat source for the at least one oven is external to a cavity of the oven.
10. The device as claimed in any preceding claim wherein the at least one oven is adapted to vent odours/gases/vapours from the oven into an exhaust duct.
11. The device as claimed in claim 10, wherein the exhaust duct contains within it the catalytic combustor.
12. The device as claimed in any preceding claim wherein the catalytic combustor is operable to extract harmful odours/gases/vapours from the combustion process before release into the atmosphere, and acts as a filter to reduce tar build up within the flueway.
13. The device as claimed in any preceding claim wherein the catalytic combustor is operable to act together with the secondary combustor to reduce emissions of the cooking/heating device and increase the efficiency of the device.
14. The device as claimed in any preceding claim wherein the catalytic combustor acts together with the secondary combustor to reduce emissions of the cooking/heating device to 2g/kg.
15. The device as claimed in any preceding claim wherein the catalytic combustor acts together with the secondary combustor to reduce emissions of the cooking/heating device to below 2g/kg.
16. The device as claimed in claims 10 to 15 wherein the exhaust duct incorporates a diverter which is operable to divert gases around the catalytic combustor.
17. The device as claimed in claim 16 wherein the diverter is manually actuable.
18. The device as claimed in claims 16 and 17 wherein the diverter is operable to be opened to prevent exhaust gases from passing through the catalytic combustor and closed to allow exhaust gases to pass through the catalytic combustor.
19. The device as claimed in any preceding claim wherein the combustion section is provided with a control to vary heat output and thus the temperature of the respective hotplate and the at least one oven.
20. The device as claimed in any preceding claim wherein a first duct is provided to channel combustion gases and heated air to the hotplate.21 The device as claimed in any preceding claim wherein a second duct is provided to channel combustion gases and heated air around the at least one oven.22. The device as claimed in any preceding claim wherein insulation is provided inside the exterior walls of the device.