This invention relates to heaters and more especially, but not exclusively,
to heaters of the type traditionally known as braziers and used mainly out of doors
for heating and cooking purposes.
In a traditional brazier, charcoal or other solid fuel is burnt in
an open topped, cylindrical metal basket or drum and heat is dispersed by radiation
and convection from the burning fuel. Characteristics of braziers include a large
heat dispersement surface and an appealing visual effect.
Disadvantages include the unwelcome smoke and fumes created as the
brazier burns and the time taken to light the brazier and to extinguish it after
The present invention sets out to provide a heater which retains the
advantageous characteristics of a brazier but which does not suffer from or at
least alleviates the disadvantages referred to above.
In the US-A-1 475 450 there is described a heater including a columnar
According to the present invention in one aspect there is provided
a heater which comprises a combustion tube connected to receive gaseous fuel or
liquid fuel dispersed within a gaseous carrier gas from a source of such fuel and
an expansion chamber in communication with the combustion tube, the heater being
characterised in that the expansion chamber has formed in its surface a plurality
of openings and is housed within an outer perforated container, the internal surface
of the perforated container being spaced from the external surface of the expansion
chamber to receive heating blocks.
The expansion chamber is preferably positioned about the circumference
of the combustion tube. Preferably, the combustion chamber is also housed within
the perforated container.
The heating blocks may comprise pieces of lava rock or stone.
The perforated container may comprise a cylindrical metal drum whose
sides are formed from metal wire. The expansion chamber and/or the combustion chamber
may be produced from steel, especially stainless steel.
The invention will now be described by way of example only with reference
to the accompanying diagrammatic drawings, in which:-
- Figure 1 is a side view in section of a heater in accordance with the invention;
- Figures 2 and 3 are side views in section of alternative heaters in accordance
with the invention.
As will be seen from Figure 1, the illustrated heater comprises a
tubular open-ended combustion chamber 1 positioned generally coaxially within
a tubular expansion chamber 2 which is closed at its upper and lower ends respectively
by a generally circular plate 3 and a ring shaped plate 4 through which the combustion
tube 1 projects. The sides of the chamber 2 are perforated to provide a multiplicity
of openings 5. These openings may be circular, rectangular or other suitable shape.
The combustion chamber and/or expansion chamber may be produced from a stainless
The combustion chamber and expansion chamber are housed within a
cylindrical container 6 whose sides are perforated to provide a multiplicity of
openings 7. The upper end of the container 6 may be closed, open or perforated
as for the container sides. The sides of the container 6 may be formed from wire
The assembly of the container, combustion chamber and expansion chamber
is supported on a stand including a plurality of legs 9. Positioned between the
legs 9 is a cylinder 10 of gaseous fuel, e.g. a liquified gas such as propane.
The cylinder is connected via a regulator valve 11 and nozzle 12 to inject gaseous
fluid into the open lower end of the combustion tube 1. A piezo electric igniter
13 is positioned within the annular spacing defined by the lower open end of the
tube 1, air for combustion purposes being drawn into the tube 1 through this spacing.
Shielding may be positioned between the cylinder 10 and the assembly
of the combustion and expansion chamber.
As will be seen from Figure 1, an annular space is provided between
the opposed side faces of the expansion chamber and the container. This space
is filled with lava rocks 14 or other heat retaining medium. Lava rocks may also
be supported on the plate 3 positioned above the expansion chamber.
In use, gaseous fuel from the cylinder 10 passes into the combustion
tube at a rate consistent with the setting of the regulator valve 11 and is ignited
by operation of the igniter 13. The igniter may be operated remotely. The ignited
mix of fuel and air passes through the combustion tube and enters the chamber 2
in which it expands and from which heat is dissipated through the openings 5 to
heat the lava rocks 14. Burning of the air fuel mix may cease within the chamber
2 or may continue within the annular space between the opposed surfaces of the
chamber 2 and container 6 and, possibly, at the surface of the container itself.
The lava rocks quickly become red hot thereby creating the heating
and visual effects of a brazier without the disadvantages normally associated
In the arrangement illustrated in Figure 2, (in which the same reference
numerals have been used for the same or similar integers of Figure 1) a cylinder
10 of liquid fuel, e.g. paraffin, is employed in place of the gas canister of Figure
1. The cylinder 10 can be pressurised using a hand or foot operated pump 15, the
pump being connected to the cylinder through a non-return valve 16. Fuel under
pressure is delivered via a tap 17 through a pipe 18 to a vaporising coil 19 and
thence to a nozzle 20 through which a jet of fuel is discharged. A shallow container
21 supporting a wick 22 is positioned below the open end of the combustion tube
In the arrangement illustrated in Figure 3, a fuel pump 23 is connected
to a fuel tank 10 through a pipe 24 to deliver fuel at a high pressure through
a pipe 25 to the fuel jet nozzle 20.
The heaters shown in Figures 2 and 3 operates effectively in the same
way as that described for Figure 1.
A restrictor may be provided within the inlet to the combustion tube
to enhance combustion efficiency. Also, the combustion tube may be positioned remote
from the expansion chamber, the one simply being in communication with the other.
The combustion tube may also be positioned outside the confines of the perforated