GB2528854A

GB2528854A - Portable burner and oven assembly

Info

Publication number: GB2528854A
Application number: GB1413561.0A
Authority: GB
Inventors: Thomas Gozney
Original assignee: ROCCBOX Ltd
Current assignee: ROCCBOX Ltd
Priority date: 2014-07-31
Filing date: 2014-07-31
Publication date: 2016-02-10
Also published as: GB201413561D0

Abstract

An oven assembly 100 comprises a burner 10 arranged exterior to a cooking chamber 102 and supplies heat to the interior of the chamber. The burner comprises a cylindrical hollow body (12, fig 1) having a base (36, fig 2D) and one or more walls defining a compartment defining a combustion zone (X & Y, fig 6). The one or more walls comprises one or more concentric skins (16, 18, 20, figs 2C 2E) and a hopper 14 in communication with the compartment and through which fuel is delivered into the compartment. The burner may communicate with the underside of the cooking chamber. The skins may comprise of one or more lateral rows of apertures (30, fig 2A), (32, 34). The outer skin may be rotated relative to a middle skin to adjust the overlap of the apertures by predetermined amounts for air to traverse. The hopper may comprise a sliding door (26). The body may comprise a baffle plate (40) having vents (42) downstream of the combustion zone and the hopper for the escape of heated air. The assembly may comprise one or more hinged legs 104. The body may be stored in the chamber for transportation.

Description

PORTABLE BURNER AND OVEN ASSEMBLY

The present invention relates to a portable burner and to an oven assembly.

Embodiments of the present invention relate to a portable oven assembly comprising a cooking chamber and a portable burner external to said cooking chamber.

Background

Ovens are most commonly used in cooking for the heating, baking or drying of a substance and generally comprise a thermally insulated cooking chamber and an internal heat source.

In a traditional oven, the cooking chamber may comprise an earth pit dug into the ground or may be constructed of a material such as brick, concrete, stone or clay.

The heat source is commonly wood or coal.

Modern cooking ovens are typically constructed of metal and/or composite materials and use gas, electricity or even microwave radiation as a heat source. There is often the facility to control the cooking temperature inside the oven and/or to control cooking conditions e.g. grill, fan assisted, heated plate, microwave.

Other types of speciality oven will be known to those skilled in the art, for example, kilns for pottery, furnaces for metalworking and autoclaves for sterilisation.

The oven type, fuel, temperature and cooking conditions used largely depends on the type of food being cooked and the desired cooking result. For example, modern electric fan assisted ovens are often preferred for baking cakes as heat is distributed evenly around the cooking chamber whilst wood-fired ovens are often preferred for cooking pizzas and breads.

We have now devised an improved burner and oven assembly. The burner and oven assembly of the present invention are portable, affordable, relatively safe to use and may be used as a replacement to a traditional wood fired oven.

Statements of Invention

According to the present invention as seen from a first aspect there is provided a portable burner arranged exterior to a cooking chamber and arranged such that a supply of heat is directed from the burner to an interior of said cooking chamber, the portable burner comprising: a body comprising a base portion and one or more walls that define a compartment, wherein in use said compartment comprises a combustion zone and wherein the walls comprise one or more skins; a hopper in communication with the compartment of the body that is arranged to deliver fuel into the compartment substantially downstream of the combustion zone.

Some embodiments of the portable burner may be described as a hybrid of a rocket stove and a gasification stove.

The air vents provide an internal airflow to the burner which produce a secondary burn.

Advantageously, the baffle at the top to creates additional combustion and a rolling flame.

Burner may be attached to the cooking chamber by one of: a twist and lock mechanism, friction fit, push fit or other means.

The portable burner of the present invention is a highly efficient adjustable heat source and is able to heat an oven body (cooking chamber) up to a temperature of 350 -400 00. The burner can be fed fuel externally via the door in the hopper without the need to open the oven body door, thus reducing the possibility of heat escaping from the cooking chamber.

Advantageously, the burner may be fed a variety of different fuel types including wood, pellets, peat etc. The burner is relatively safe to use and can be readily handled without the risk of burns to the user.

According to the present invention as seen from a second aspect there is provided an oven assembly comprising the portable burner described above.

The applicants found that surprisingly, by removing the heat source from the traditional position of inside the oven body and installing the burner of the present invention to the outside not only saved space and decreased the size and weight of the oven product, but allowed a highly efficient and quality cooking process.

Existing burner technology was not suitable to be located externally of the oven body and did not maintain sufficient heat for cooking and/or lacked the necessary structural features.

Advantageously the oven assembly is lightweight and compact and thus can be readily transported and can be used where space is limited.

The cooking technique of the oven replicates a traditional wood fired oven but unlike a traditional oven, the oven assembly of the present invention is also portable, is much safer to use and can be manufactured at much lower costs.

Specific Description

An embodiment of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an illustration of a perspective view of a burner according to an embodiment of the present invention as seen from a first aspect; Figures 2 a-f illustrates the component parts of the burner shown in Figure 1 and how they are assembled together; Figures 3 a-e illustrates part of an oven assembly according to an embodiment of the present invention as seen from a second aspect; Figure 4a illustrates an oven assembly according to an embodiment of the present invention, comprising the burner shown in Figure 1 and the cooking chamber shown in Figures 3 1-e, the oven assembly is shown cut through and in an operational configuration in Figure 4b; Figure 5 illustrates the oven assembly as shown in Figure 4 with the burner shown in Figure 1, the oven assembly in a storage configuration; and Figure 6 illustrates the burner as shown in Figures 1 and 2 a-f in use.

Referring to Figures 1 and 2 a-f, there is shown a burner 10 comprising a substantially cylindrical hollow body 12 and a hopper 14 protruding from the body 12.

The body 12 comprises three skins: an inner skin 16, middle skin 18 and an outer skin 20. All three skins comprise a substantially rectangular shaped aperture 22 such that when the apertures of each skin respectively are aligned, an effective aperture is created from an outside of the burner 10 to an inside of the burner suitable for receiving the hopper 14 at an angle of 70 degrees relative to the longitudinal axis of the body 12. The inner 16 and middle 18 skins of the body 12 are secured together with three mechanical fixing elements (brackets) 24 ata top end of the burner 10.

The outer skin 20 is moveable relative to the inner 16 and middle 18 skins.

The hopper 14 is a substantially rectangular tray with an open end that is inserted and fixed through the effective aperture 22 in the burner body 12, and a closable end comprising a door 26. Due to the high temperatures created inside the burner body 12 in use, fixing the hopper 14 to the burner 10 by mechanical means would not be practical thus in this embodiment of the burner 10, a clip mechanism is used. The door of the hopper 26 has a sliding mechanism to move the door between open and closed positions and the door locks in place at each position. The door of the hopper 26 also has a catch or clip to secure it in the shut position. More specifically a sprung clip arrangement is used to secure the door. Two sprung clips, one located either side of the door include tabs, the tabs flex to securely hold the door when it is closed.

The mating surfaces of the door are flush when it is closed.

The triple-skinned burner 10 is designed to provide efficient airflow in use and to be safe for a user to handle. The inner skin 16 (or "burn chamber") comprises a lateral row of circular apertures 28 at the top end of the burner 10 which form air vents.

Further circular apertures (air vents) are arranged in four additional lateral rows 30 between a lower portion and a mid-portion of the burner 10.

The middle skin 18 is made of solid steel and comprises a lateral row of circular apertures 32 at the bottom end of the burner 10 which form air vents. In this embodiment, these circular apertures 32 on the middle skin are relatively larger in diameter to the circular apertures 28,30 on the inner skin 16.

The outer skin 20 is made of perforated steel which aids airflow between the outer 20 and middle 18 skins such that minimal heat is transferred from the inner 16 and middle 18 skins to the outer skin 20. This design feature enables a user to handle the outer skin 20 when the inner burn chamber 16 is still hot.

The outer skin 20 further comprises a row of substantially rectangular shaped apertures 34 at the bottom end of the burner which also form air vents. The outer skin 20 is moveable relative to the inner 16 and middle skins 18 such that the row of apertures 34 on the outer skin 20 may be overlapped with the row of apertures 32 on the middle skin 18 by a predetermined amount. The amount of overlap between these rows of apertures 32, 34 controls the air flow to a combustion zone inside the burner 10 and thus the temperature may be controlled.

The body further comprises a base plate 36 arranged to define the base of the combustion zone and a top plate 38 comprising a baffle 40 and air vents 42 adjacent the baffle 40 such that hot air can escape from the burner 10. The baffle 40 is located below the upper portion of the top plate 38, in the preferred embodiment 10 mm below the upper portion of the top plate. Both the base plate 36 and top plate 38 are fixed to the outer skin 20 of the body 12 with screws or similar.

Referring to Figures 3 a-e, there is shown part of an oven assembly 100 according to an embodiment of the present invention, the oven assembly 100 comprising a cooking chamber 102 and three legs 104. The cooking chamber 102 comprises a substantially rectangular, flat cooking floor 106 and a substantially domed roof 108 with closures at each longitudinal end of the chamber. The structure of the base of the domed roof 108 is tapered, the smaller end comprising the cooking floor 104. The distance from cooking floor 104 to the top of the oven assembly is 67mm. Similarly to the burner 10, the domed roof 108 of the cooking chamber 102 has a three-skinned construction comprising: inner 110, middle 112 and outer 114 skins. The closure at one end comprises a door 116 hinged along a lower edge, whilst the closure at the other end 118 is fixed.

A plurality of air vents 118 are located on the domed roof 108 at the longitudinal end comprising the door 116. When fully open, the total area of the air vents 118 on the domed roof 108 is equal to the area of the aperture in the cooking floor, and less than the cross-sectional surface area of the burner 10 of the oven assembly 100. These air vents 118 are hinged such that the heat inside the cooking chamber 102 can be adjusted i.e. heat can be set at the top of the cooking chamber 102 by opening the higher (or inner) vents and can be set at the bottom of the chamber by opening the lower (or outer) vents.

The three legs 104 are hinged from an underside of the cooking chamber 102 and also hinged part way down each leg. There is a lock and release mechanism to secure the legs 104 in folded and unfolded positions. The legs 104 are made of stainless steel and are perforated to reduce the overall weight of the oven assembly 100. Other suitable materials can be envisaged.

As seen in Figure 3e, the cooking floor 106 comprises a circular aperture 120 that extends from an underside to the inside of the cooking chamber 102. The aperture 120 is suitably dimensioned to receive atop portion of the burner 10 shown in Figures 1 and 2 a-f and further comprises a clip mechanism to fix the burner 10 in place.

In use, the burner 10 will be fixed in place in the aperture 120 on the cooking floor 106 such that the top plate 38 comprising the baffle 40 sits within the aperture 120 adjacent and close to but not flush with the cooking floor 106. The spacing in the preferred embodiment is 67mm from the baffle (plate) 40 to the cooking floor 106 of the burner and 57mm from the cooking floor 106 to the top of the burner 10. When fuel inside the burner 10 is lit, hot air will rise from the combustion zone near the base of the burner 10, will travel downstream of the burner 10 until it hits the baffle 40 and eventually escape through the air vents 42 in the top plate 38 of the burner 10.

This action transfers heat to the cooking floor 106 such that food items placed on the cooking floor 106 e.g. pizza can be cooked similarly to a wood-fired clay oven.

The burner can fed any solid fuel source such as wood, coal, pellets, peat briqueftes, smokeless fuels such as coalite, anthracite beans.

The oven assembly further comprises a handle on the door for easy opening and a strap such that the oven body may be safely and easily transported by a user. It is envisaged that the oven body will be transported by a user in a storage configuration with the hinged legs in their folded configurations and the fixed closure end 118 facing downwardly.

The majority of the oven assembly is made of stainless steel whilst the floor 106 of the cooking chamber 102 is made of cordierite.

Referring to Figure 4, there is shown an oven assembly 100 according to an embodiment of the present invention, as seen from the second aspect. The oven assembly 100 comprises the burner 10 shown in Figures 1 and 2 a-f and the cooking chamber shown in Figures 3 a-e. The oven assembly 100 is shown in an operational configuration ready for cooking.

The burner is attached to the oven body by inserting the top portion of the burner into the aperture in the underside of the oven body and twisting the burner to engage the catch mechanism which holds it securely in place. The simple catch mechanism means that the oven assembly can be quickly and simply assembled and disassembled.

Referring to FigureS, there is shown an oven assembly 100 in a storage configuration for transportation or storage. The legs 104 are in their folded position such that they lie flat against the underside of the cooking chamber 102. For storage or transportation, the burner 10 will be inserted into the cooking chamber 102 via the oven door 116 (as shown by the arrow in Figure 5). The oven door 116 will then be shut to contain the burner 10. It will be appreciated that it may only be safe to put the oven assembly 100 in said storage configuration when the inside of the oven cooking chamber 102 has cooled sufficiently after use. Thanks to the safety features of the burner 10, it is envisaged that the user will be able to handle the burner 10 immediately after use without risk of burns.

This particular embodiment of the oven assembly 100 hereinbefore described when in the storage configuration is advantageously designed to fit six-fold in a transportation pallet thus optimising the number of units per pallet. The oven assembly also complies with transportation weight restrictions and each oven assembly (including burner) weighs under 25 kg.

Figure 6 shows the burner 10 in use. Fuel is being burnt in the combustion zone X and the flow of air through the triple-skinned burner body 12 is shown by arrows.

It is envisaged that in use, after assembling the oven assembly 100 in the operation configuration as shown in Figure 4, the hopper door 26 will be opened and a lit organic firelighter (not shown) will be inserted. The firelighter will fall through the hopper 14 to rest at the base of the burner 10 to create a combustion zone X. Kindling will then be inserted into the burner 10 through the hopper 14 which will deliver and support the kindling above the firelighter, downstream of the combustion zone X. The angle of the hopper 14 will allow embers to fall to the base of the burner as the kindling burns to create a bed of embers. Fuel can be inserted into the burner 10 downstream of the combustion zoneXas and when required via the hopper 14. The main combustion zone (fire core) X will be just below the hopper in a lower portion of the burner 10 adjacent the base 36, and the hopper 14 holds additional fuel above said main combustion zone X creating a secondary combustion zone Y, located in the vicinity and just above the baffle (plate) 40. The secondary combustion zone is a ring of flame (blue flame) that is created by air being drawn in through the perforations at the bottom if the middle or inner skin and coming back in through the perforations at the top and upper portion and through the middle of the inner skin. As the fuel burns, hot air will rush around inside the burner 10 and travel downstream away from the base plate 36 towards the top portion of the burner 10 attached to the cooking chamber 102 of the oven assembly 100 where it will first hit the baffle plate 40. The baffle plate 40 acts as an obstacle and will force the air to move faster inside the burner and thus helps to reignite the hot oxygen from the secondary combustion zone Y just above the baffle plate 40. As hot air contacts or goes past the baffle plate 40 through the apertures 28 at the top of the burner 10, the top plate 38 is heated and the floor 106 of the cooking chamber 102 is heated.

In one embodiment (not shown), the oven assembly 100 comprises ridges on the baffle plate 40 which create a more turbulent airflow inside the burner 10. This has been found to improve the efficiency and quality of cooking.

The arrangement of air vents (apertures) in the inner 16, middle 18 and outer 20 skins of the burner 10 significantly aid the efficient combustion process. Air is sucked into the burner 10 through the apertures 30, 32, 34 in the base of the outer 20, middle 18 and inner 16 skin which may or may not be aligned. Air may then flow downstream towards the top of the burner 10 between the inner 16 and middle 18 skins and enter the burn chamber via the additional rows of apertures 30 on the inner skin located between the lower and upper portions of the burner wall.

It will be appreciated that when all three rows of apertures 30,32,34 in the lower portions of the three skins 16,18,20 are aligned, the flow of air will have little or no hindrance to the inside of the burner thus fuel will burn much hotter. The extent to which the apertures (air vents) 34,32 on the outer 20 and middle 18 skins are aligned may be adjusted by the user.

The door of the hopper 26 may optionally be left open for additional air flow.

It will be appreciated that the above described embodiments are given by way of example only and that various modifications thereto may be made without departing from the scope of the invention. For example, rather than being separate, the burner and oven body may integrally fixed together. The hopper may be removable and may be arranged in an alternative orientation, it may be at an angle of between 30 and 80 degrees relative to the longitudinal axis of the body.

Claims

Claims 1. A portable burner arranged exterior to a cooking chamber and arranged such that a supply of heat is directed from the burner to an interior of said cooking chamber, the portable burner comprising: a body comprising a base portion and one or more walls that define a compartment, wherein in use said compartment comprises a combustion zone and wherein the walls comprise one or more skins; a hopper in communication with the compartment of the body that is arranged to deliver fuel into the compartment substantially downstream of the combustion zone.
2. A portable burner according to claim 1, wherein the body is substantially cylindrical.
3. A portable burner according to any preceding claim, wherein the body walls comprise three skins: an inner skin, a middle skin and an outer skin.
4. A portable burner according to any preceding claim, wherein the inner skin comprises one or more lateral rows of apertures.
5. A portable burner according to any preceding claim, wherein the mid skin and outer skin each comprise a lateral row of apertures substantially adjacent the base portion.
6. A portable burner according to any preceding claim, wherein the outer skin comprises a plurality of perforations that extend between the base portion and an upper portion of the outer skin.
7. A portable burner according to any preceding claim, wherein when overlap between the apertures in the lower portion of the mid skin and the apertures in the lower portion of the outer skin may be adjusted by a predetermined amount.
8. A portable burner according to any preceding claim, wherein the outer skin may be rotated relative to the middle skin.
9. A portable burner according to any preceding claim, wherein the burner comprises a region located between the inner and middle skin for air to travel between the inner skin and middle skin.
10. A portable burner according to any preceding claim, wherein the hopper further comprises a door arranged to provide access to the inside of the burner.
11. A portable burner according to any preceding claim, wherein the portable burner further comprises a baffle plate downstream of the combustion zone and hopper.
12. A portable burner according to any preceding claim, wherein the hopper comprises multiple combustion elements.
13. A portable burner substantially as hereinbefore described with reference to Figures 1 and 2.
14. An oven assembly comprising a cooking chamber and a burner according to any of claims 1-13, wherein the burner is located exterior the cooking chamber and is arranged to direct heat into said cooking chamber.
15. An oven assembly according to claim 14, wherein the burner is in communication with an underside of the oven body such that in use, heat from the burner enters the oven body.
16. An oven assembly according to claim 14 or 15, wherein the oven further comprises one or more hinged legs.
17. An oven assembly according to any of claims 14-16, wherein said one or more legs are made of a perforated material.
18. An oven assembly substantially as hereinbefore described with reference to Figures 4 and 5.