GB2486696A

GB2486696A - Heating device

Info

Publication number: GB2486696A
Application number: GB1021799.0A
Authority: GB
Inventors: Anthony Laurence Friend; George Lawrence Friend
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-12-23
Filing date: 2010-12-23
Publication date: 2012-06-27
Also published as: GB201021799D0

Abstract

A heating device such as a barbecue comprises a casing 1 containing a tray 2 separated by a perforated plate 12. A gas/air mixture introduced into the lower compartment of the tray, perculates through the perforated plate, permeates non-combustible granular material contained within the upper compartment of the tray and upon ignition at the surface creates a fluidised bed of flame which disperses evenly over the containment. This heat source can be utilised in a number of ways: the cooking of food, supported on a grid above the heat source, which rests on rods located and supported via side-screens attached to the ends of the casing and secured against the raised lid. When not in use this grid, the side-screens, the non-combustible granular material and rods are all retained within the confines of the casing making the entire device self contained and portable. A tapered venture 6 may be secured to an end plate so that gas and air may be mixed in a compartment below the tray 2.

Description

HEATING DEVICE

Background

Conventional gas fired barbecues use the gas to heat a layer of lava rock to a suitable temperature for cooking and require to be lit for a considerable time (20 -40 minutes) before cooking can commence.

The lava rock and gas burner are housed within a common container which gets very hot prior to and during the cooking process and can present a danger to the cook and others.

The grid for supporting the food whilst cooking can be at a fixed height and so limits the quality of the cooking.

Upon completion of the cooking when the gas is turned off,considerable latent heat in the lava rock and casing dissipates into the air and is wasted.

This invention relates to a heating device, which has particular, but not exclusive, application in a gaseous fuel fired grill or barbecue. The invention also relates to such a gril or barbecue which requires no warm up period and leaves minimal latent heat after the gas is turned off.

The casing can be made in such a way that it remains relatively cool whilst cooking is in progress with a food support grid that can be adjusted for height whilst the cooking is in progress and after use can be stowed within the casing and transported.

U.K. Patent Specification:-2219391B discloses a gaseous fuel fired grill having a tray for holding a bed of non-combustible granular material within which are embedded apertured gas distribution members. ln use, the gas permeates through the bed to the surface thereof where it can be ignited. The gas distribution members are supplied from a common manifold into which a venturi chamber feeds a gas/air mixture produced in said chamber. The venturi chamber and manifold are disposed outside of the tray within a casing of the grill. It would clearly be desirable to reduce the size, inefficiency and/or number of parts of the gas/air production supply assembly and also by this, or other means to produce a more compact grill.

Statement of Invention

An object of the invention is to provide an effective, compact heating device which can be used, but not exclusively, for the conversion of other existing types of heaters, grills and barbecue type devices of various types, styles, shapes and configurations, to enable functionality utilising the configuration of the parts and system described herein which produces the gas/air mixture and which is delivered by the means so described from suitably manufactured containers and a further object is to provide an efficient and compact grill or barbecue.

According to one aspect of the present invention, there is provided a heating device comprising an open-topped container, the container having an area to which a mixture of air and gaseous fuel passes, said area being separate from and in communication with a compartment of the container, which compartment is intended to be filled or partly filled with a non-combustible granular material, so that in use, the gas/air mixture passes into said compartment and percolates upwardly through said material for combustion at the surface thereof. Preferably the heating device includes means within the container for inducing air through said means to mix with gaseous fuel supplied to the means, in use, the resuftant mixture being received in said area. More preferably the compartment is above said area.

According to a second aspect of the present invention there is provided a portable grill/barbecue comprising a casing with a lid, an open topped container disposed in the casing, a compartment in the container intended to be filled or partly filled with a non-combustible granular material, the container having an area, separate from and in communication with said compartment, into which a mixture of air and gaseous fuel is received, in use, the gas/air mixture passing into the compartment and percolating upwardly through said material for combustion at the surface thereof, and removable cover means receivable over the surface of said material, in use, and retained there against by closure of the lid so that the grill/barbecue can be transported.

Desirably the cover means are respective side screens fittable to opposite sides of the grill/barbecue, in use, and preferably these plates, either alone, or together with grid support bars, support, conveniently in a height adjustable manner, a grid for cooking food.

The grid and support bars, if provided, advantageously is or are stowable above or below the side plates and within the confines of the casing and when said lid is closed, can form part of the cover means.

The invention will now be described by way of example with reference to the accompanying drawing -page 4 of this manuscript.

A Gas Fired Barbecue comprising a Metal Casing (Detail 1) and located within the casing a Metal Tray (Detail 2).

The Metal Tray (Detail 2) has a perforated base and is supported within the casing (detail 1).

This assembly is welded between End Plates (Detail 3) and so creates a compartment below the tray.

A Tapered Venturi (Detail 6) is secured to the end plate (detail 3) with the throat of the venturi open to the Air Intake (Detail 7).

The air intake is fitted with an injector (Detail 8).

The tray (detail 2) is filled with a Non-Combustible Granular Material, (Detail 12).

When gas (Propane, Butane or Natural Gas) is fed through the appropriate injector (detail 8), air is induced and a gas/air mixture is formed in the lower compartment of the casing/tray assembly.

The air/gas mixture passes through the perforations in the tray (detail 2), perculates throughout the granular material (detail 12) and upon ignition at the surface produces a Fluidized Bed of flame.

The Hinged Lid (Detail 4) when opened for use is supported on either side by Side-Screens (Detail 5).

The side-screens are secured to the end plates (detail 3) by Hinges (Detail 14) which are attached to the side-screens and to the casing end plates.

The Side-Screens are provided with vertical lines of holes having a connecting slot between them.

A Food Support Grid (Detail 9) is located between the side-screens and is supported by the Food Grid Support Rods (Detail 10).

The Food Grid Support Rods (Detail 10) have Spring Loaded Locating Spigots (Detail 11) which locate within the holes in the Side-Screens (Detail 5).

By withdrawing the spigots from the holes in the side-screens, the rods which support the Food Grid (Detail 9) are enabled to be raised or lowered and by relocating the spigots in another set of holes the food grid can be positioned to a different height.

On completion of cooking the food grid support rods (detail 10) are withdrawn from the side-screens and are stowed between the End Plates (Detail 3) underneath the casing.

The food grid locates on the top of the tray and the side-screens fold down.

The Lid (Detail 4) is closed and secured by the Allen Screws (Detail 15) and the complete barbecue can be relocated.

Advantages Thus a grill of the present invention possesses several advantages over both conventional gas fired barbecues which use gas to heat a layer of lava rock and also over the prior art fuel fired grill referred to hereinbefore and in a preferred embodiment the quality of the cooking can be improved in that a grid for supporting the food is not fixed at a single height. Moreover a device of the present invention requires no warm up period prior to cooking and leaves minimal latent heat after the gas is turned off. As described, components of the device can after use, be stowed within itself and transported.

With regard to the prior art referred to, it will be apparent that in one embodiment of the present invention mixing of the air and gas takes place within the tray and not by way of a venturi and manifold connected outside of the tray. In this way the number of component parts is reduced and the construction thus simplified, the mixture being received in a lower part of the tray rather than directly into the granular bed. Despite not positively feeding the mixture to various parts of the bed, the embodiment shown has been found to be effective to distribute the mixture equally to all parts of the bed so as to provide a substantially uniform flame bed over the whole surface of the refractory material so as to provide a uniform convention effect for the cooking process. In particular, the air/gas mixture travels only a short distance from the initial mix point and undergoes only one change of direction before reaching the the combustible surface area, in one example. In the prior art construction the mixture travels much further and undergoes several changes of direction before combustion. It can thus be appreciated that as the mixture travels a shorter distance and with far less deflections, a stronger initial induction will occur leading to a corresponding resultant improvement in effective heat delivery at the combustible surface.

A further advantage of mixing the air and gas within the tray is that it enables the tray to constitute a self-contained heating device and according to one aspect of the present invention, this heating device can be used in applications other than a grill/barbecue. Although, as described, this self contained heat source can be used to convert a conventional non-gas fired barbecue or appliance to a gas fired one. This self-contained and thus portable heat source can be used in other applications, for example, where a heat exchange arrangement is required. It has been found that the same gas jet can be used with butane or propane and possibly with other bottled gases, a different nozzle only being required for use with Natural Gas.

Accordingly in one aspect, the invention relates to the provision of a heating device which has a wide range of applicability. In another aspect of the invention, the mixing of the air and gas could take place either within or outside of the tray, but with the tray being thermally isolated from the casing at its sides, for example by way of an air gap or by way of thermal insulation.

With all embodiments having mixing outside the tray the air supplied for

S

mixing with the fuel could be compressed air, rather than induced ambient air from the exterior of the casing. The use of compressed air would increase the performance of the heat sourceS However, even using compressed aire, induction of the primary mixing air as in the described embodiment may be required in order to effect initial combustion.

Finally, in a further aspect of the invention there is provided a portable grill/barbecue, it mer&y being necessary to provide, for use a suitable stand on which to place the casing and to connect a source of bottled gas to the gas tap at the exterior of the casing. As described the quick warm up and cool down together with the means of securing the bed in place allows quick and easy transportation or storage between periods of use. In an alternative embodiment the casing could be enclosed such that it could contain the liquid gas required for combustion, being refilled as required. A tube or pipe would lead from the enclosed casing to deliver the gas, now in gaseous instead of liquid form, to the venturi mouth where, as previously described, it mixes with primary air. Thus without the need to transport a bottle of gas, the device is even more portable and self contained.

Claims

Claims 1). A heaUng device comprising a metal casing containing a fixed metal tray horizontally divided into two compartments by a suitably caUbrated perforated metal plate, the upper compartment s fifled with a non-combustible granular material, within the lower compartment a venturi is fixed with the throat of the venturi open to the side of the tray for the purpose of introducing a gas/air mixture to the lower compartment of the casing, this mixture passes through the perforations in the metal plate, permeates through the granular material and on ignition at the surface, produces a fluidized bed of flame.
2). A Gas Fired Fluidic Barbecue/Char Grill according to Claim 1, comprising a hinged lid with side screens secured on each side of the casing which retain the lid in the open posifion and hold rods which support a food holding grid above the surface of the tray.
3) A Barbecue/Char Grill according to Claim 2, with means of raising and lowering the food support grid to different positions above the surface of the tray whilst cooking is in progress.

4). A Barbecue/Char Grill according to Claim 3, whereby after use the side screens and food support grid are stowed within the tray to restrict and contain the granular material from movement when the lid is closed and secured and the Barbecue/Char Grill is transported.

5). A Barbecue/Char Grill according to Claim 4, whereby after use the food support grid rods are located within the confines of the casing to enable the unit to be complete and self contained.