WO1998053255A1

WO1998053255A1 - Improved brazier

Info

Publication number: WO1998053255A1
Application number: PCT/AU1998/000345
Authority: WO
Inventors: Geoff Roach
Original assignee: Geoff Roach
Priority date: 1997-05-16
Filing date: 1998-05-12
Publication date: 1998-11-26
Also published as: AUPO686197A0

Abstract

A brazier (1) including a chamber (2) to contain a fuel (4) for combustion, a plurality of elongate support members (5) to maintain the chamber at a predetermined height above a support surface (6), and at least one convection duct mounted adjacent the chamber. The duct has upper (8) and lower (9) apertures arranged such that air heated within the duct rises by convection and is expelled through the upper aperture, thereby causing relatively cool air to be drawn into the duct through the lower aperture for subsequent heating in a substantially continuous cycle.

Description

TITLE: IMPROVED BRAZIER

FIELD OF THE INVENTION

The present invention relates to combustion based heating devices, and more

specifically to heaters used for burning coal, charcoal or other solid fuel, out of doors.

The invention has been developed primarily for use with coal burning braziers, and

will be described hereinafter with reference to this application. It will be appreciated,

however, that the invention is not limited to this field of use.

BACKGROUND OF THE INVENTION

Braziers have existed in a number of forms for use as heating devices for many

years. Usually, they include some form of generally cylindrical combustion chamber

defined by a base and peripheral side walls adapted to contain fuel such as wood or coal.

The side walls are often perforated, or formed from metal strips, to form a cage to

contain the burning fuel whilst ensuring an adequate supply of air to facilitate

combustion. The cage is usually supported above the ground or other support surface on

a relatively rigid stand, or may be hung from an overhead bracket.

In use, a fuel such as coal, charcoal or wood is stacked into the combustion

chamber and ignited. As the fuel burns, the brazier becomes hot, and radiates heat into

the surrounding atmosphere. Although most often used outdoors for heating, braziers

can also be used indoors, subject to the provision of an appropriate exhaust flue or

adequate ventilation.

A substantial disadvantage with prior art braziers is energy wastage. More

specifically, as the fuel burns and the brazier heats up, a substantial proportion of the

energy of combustion is wasted as the exhaust gases rise rapidly into the atmosphere. These exhaust gases radiate very little heat to the surrounding atmosphere, and so tend

not to provide much additional warmth. As such, braziers rely almost entirely on radiant

heat from the cage and the fuel, whilst convective heat is almost entirely lost in a vertical

updraft.

It is an object of the present invention to overcome or substantially ameliorate at

least some of the disadvantages of the prior art.

DISCLOSURE OF THE INVENTION

Accordingly, the invention provides a brazier including a chamber to contain a fuel

for combustion, a plurality of elongate support members to maintain the chamber at a

predetermined height above a support surface, and at least one convection duct mounted

adjacent the chamber, the duct having upper and lower apertures arranged such that air

heated within the duct rises by convection and is expelled through the upper aperture,

thereby causing relatively cool air to be drawn into the duct through the lower aperture

for subsequent heating in a substantially continuous convection cycle.

Preferably, the upper aperture is configured to expel the heated air away from the

brazier in a lateral or radial direction.

Preferably also, the duct is defined by a bore extending longitudinally within one

of the support members. Preferably, each of the support members includes a duct

defined by a longitudinally extending bore such that the support members and the

convection ducts are effectively integral.

In alternative embodiments, however the ducts may be formed separately from the

support members. Preferably, each support member takes the form of a hollow generally vertically

extending pipe, the upper and lower apertures being defined by respective openings at

opposite ends of the pipe.

Preferably also, an upper portion of the pipe is curved outwardly such that the

upper aperture faces laterally away from the brazier.

Preferably, a lower end of each pipe is similarly curved such that the lower

opening also faces laterally away from the brazier.

It is preferable that the lower aperture is disposed, in use, at a height below the

combustion chamber, whilst the upper aperture is generally located above the

combustion chamber.

Desirably, the support members are welded or bolted to the combustion chamber.

Preferably, the base and peripheral side walls of the chamber are formed from

scored and expanded metal plate to form a perforate mesh.

BRIEF DESCRIPTION OF THE DRAWING

A preferred embodiment of the invention will now be described, by way of

example only, with reference to the accompanying drawing which is a longitudinal

section through the central axis of a brazier, according to the invention.

PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawing, a brazier 1 includes a chamber 2 defined by a base and

peripheral side walls 3 forming a generally cylindrical cage to contain fuel 4 for

combustion. The base and peripheral side walls 3 are formed from scored and expanded

metal plate, to ensure adequate airflow to the interior of the combustion chamber 2.

However, any other suitable configuration or material may be used. The brazier further includes a plurality of elongate support members 5 attached to

the side walls 3 to maintain the chamber 2 at a predetermined height above a support

surface, in this case the ground 6. The brazier also has a plurality of ducts defined by

bores 7 extending longitudinally through respective support members 5. Each duct

includes an upper aperture 8 and a lower aperture 9.

The support members 5 are welded to the outside of the peripheral side walls 3 in a

generally vertical orientation. Respective upper and lower ends of the support members

5 are curved outwardly .to point away from brazier in a generally radial direction. In the

embodiment shown, six circumferentially spaced apart support members 5 are used.

However, any suitable number and combination of support members, with or without

integral internal ducts, may be used. For example, the support members may simply be

feet or legs which maintain the chamber at a predetermined height from the ground. The

ducts may then take the form of separate tubes or similar formations disposed adjacent

the side walls, such that a similar convective cycle is established.

In use, the chamber is loaded with a charge of fuel 4, which is then ignited. As the

fuel burns, the side walls 3 become hot, as do the adjacent portions of support members

5. Air thus heated within the bores rises due to its lower relative density, and is expelled

from the upper apertures 8 in a direction laterally away from the brazier 1. Displacement

of air from within the bore 7 causes relatively cool air to be drawn into the ducts through

the lower apertures 9, and so the cycle continues.

In other embodiments, apertures may simply be formed at one or more points

along the length of one or more hollow support members similar to those shown in the accompanying drawings. The apertures need only be configured to ensure that a

convection current is induced by the effects of the burning fuel on the duct.

It will be appreciated that this arrangement causes a continuous convective flow of

air into the lower apertures, through the ducts and out of the upper apertures 8 in a

generally horizontal, rather than vertical direction, so as to provide additional heat

around, as distinct from above, the combustion chamber. In this way, the present

invention substantially increases the efficiency and effectiveness of the brazier by

making use of convective as well as radiant heat and thereby making available for

heating more of the energy released by the burning fuel. Moreover, this occurs

automatically, without the need for fans or other mechanical devices or moving parts.

Thus the invention represents a commercially significant improvement over the prior art.

Although the invention has been described with reference to a number of specific

examples, it will be appreciated by those skilled in the art that the invention may be

embodied in many other forms.

Claims

CLAIMS:-

1. A brazier including a chamber to contain a fuel for combustion, a plurality of

elongate support members to maintain the chamber at a predetermined height above a

support surface, and at least one convection duct mounted adjacent the chamber, the duct

having upper and lower apertures arranged such that air heated within the duct rises by

convection and is expelled through the upper aperture, thereby causing relatively cool air

to be drawn into the duct through the lower aperture for subsequent heating in a

substantially continuous convection cycle.

2. A brazier according to claim 1 wherein the upper aperture is configured to expel

the heated air away from the brazier in a lateral or radial direction.

3. A brazier according to either one of the preceding claims wherein the duct is

defined by a bore extending longitudinally within at least one of the support members.

4. A brazier according to any one of the preceding claims wherein each of the support

members includes a duct defined by a longitudinally extending bore such that the

support members and the respective convection ducts are effectively integral.

5. A brazier according to claim 4 wherein each support member takes the form of a

hollow generally vertically extending pipe, the upper and lower apertures being defined

by respective openings at opposite ends of the pipe.

6. A brazier according to claim 5 wherein an upper portion of the pipe is curved

outwardly such that the upper aperture faces laterally or radially away from the brazier.

7. A brazier according to claim 6 wherein a lower end of each pipe is similarly

curved such that the lower opening also faces laterally or radially away from the brazier.

8. A brazier according to any one of claims 1 to 3 wherein at least one of the ducts is

formed separately from the support members.

9. A brazier according to any one of the preceding claims wherein the lower aperture

is disposed, in use, at a height below the combustion chamber, whilst the upper aperture

is generally located above the combustion chamber.

10. A brazier according to any one of the preceding claims wherein the support

members are welded or bolted to the combustion chamber.

11. A brazier according to any one of the preceding claims wherein the base and

peripheral side walls of the chamber are formed from scored and expanded metal plate to

form a perforate mesh.

12. A brazier substantially as herein described with reference to the accompanying

drawing.