GB2182765A

GB2182765A - Gas burner assembly

Info

Publication number: GB2182765A
Application number: GB08624281A
Authority: GB
Inventors: Malcolm Campbell Oakes; John James Burgess
Original assignee: Taymar Ltd
Current assignee: Coleman Taymar Ltd
Priority date: 1985-11-08
Filing date: 1986-10-09
Publication date: 1987-05-20
Also published as: GB8527583D0; GB8624281D0; GB2182765B

Abstract

A liquifiable-petroleum-gas burner assembly, for a blowtorch, heater, or lantern comprises a body 12 connected to a gas supply pipe 11 and a burner tube 14, and carrying a jet nozzle 20. A tubular conduit 22 provides a fuel flow path, from the supply pipe 11 to the nozzle 20, which passes through a flame zone, at the free end 24 of tube 14, to ensure that any liquid fuel entering conduit 22 is vaporized before combustion. The conduit extends upwardly from fuel passage 17a, doubles back on itself, and feeds a passage 17b leading to the nozzle. <IMAGE>

Description

SPECIFICATION Gas burner assembly This invention relates to a gas burner for L.P.G., such as a propane or butane. The invention relates particularly, but not essentially, to a blow-torch.

When an L.P.G. appliance is tilted so that its reservoir is above its burner, a stream of liquid gas can issue from the burner. Such a stream burns coolly, so that the high temperature of the flame is lost which is detrimental in plumbing and other operations. Further, the liquid stream spreads a flame a large distance and can be a hazard if work is being performed near flammable substances or materials. Clearly, in plumbing and other operations the misfunction of a liquid stream flame is most convenient and potentially dangerous.

A diaphragm regulating valve can be used to prevent such flow, but is expensive and complicated.

An object of the present invention is to provide a gas burner assembly which eliminates the danger of a liquid gas flame and which is cheap and simple to produce.

Accordingly, the invention provides a burner assembly including a body having an inlet for gas and an outlet jet, a burner tube extending from the body, surrounding the jet and having an aperture or apertures for the entry of air for combustion, wherein a gas flow conduit provides a gas flow path which extends from the inlet to a flame zone of the burner tube and back to the jet, to ensure that all fuel reaching the jet must pass to the flame zone and be heated above its vaporization temperature before issuing from the jet, ensuring that a liquid fuel stream cannot issue from the jet.

The flame tube can be integral with or attached to the body. At or adjacent the flame zone, at an end of the flame tube remote from the body, the tube can contain a flame holding formation.

The body can be internally divided to have two separate chambers, an inlet chamber connected to a gas supply pipe and an outlet chamber connected to the jet nozzle.

The gas flow conduit can be in the form of a hairpin-shaped length of tubing having one of its ends connected to the inlet chamber and the other to the outlet chamber, its bight being disposed in the flame zone.

The conduit can be wholly within the flame tube, or can have only its bight within the tube. Alternatively, the central part of the conduit can surround the flame exit orifice of the tube, inside or outside the tube.

The tube can be of overall cylindrical shape, having a part of its walling deformed outwardly to form a U-section channel accommodating the conduit.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein: Figure 1 is an exterior perspective view of a preferred burner of the invention; Figure 2 is a longitudinal cross-sectional view on an enlaged scale, of the burner of Fig. 1; and Figure 3 is a view of the burner in the direction of arrow Ill in Fig. 1, a flame tube of the burner being cut away to show other parts.

A preferred burner assembly 10 of the invention can be part of an L.P.G. appliance (not shown) such as a blow torch which includes a reservoir of L.P.G. such as a disposable canister to which is detachably secured a connector having a simple on/off and regulating valve and from which extends a gas pipe 11.

The pipe 11 sealingly connects with a body 12 which has: a downstream part 13 constituting a receiving plug for an upstream end of a flame tube 14; a central larger diameter part providing a shoulder 15 for tube 14; and an upstream spigot 16 screwediy connected to pipe 11. The body 12 has, internally, a downstream outlet chamber 18 and an upstream inlet chamber 19. The chamber 18 has a jet nozzle 20 connected thereto and discharging along the axis of the tube 14.

A protrusion 21 on one peripheral part of the body 12 serves to mount a hairpin-shaped gas flow conduit 22. Respective bores 17a, 17b in the body 12 connect the ends of conduit 22 to the chambers 18 and 19. The bend 23 of the hairpin-shaped conduit 22 is adjacent a free downstream flame end 24 of the tube 14, which is generally cylindrical in shape, a part of the periphery adjacent body 12 having been deformed outwardly to create a channel-section recess 27 which encloses a part of the conduit 22. The part of tube 22 between recess 27 and end 24 of the tube 14 lies inside the cylindrical tube. A flame holder 28 is cut away at 29 to accommodate tube 22. Tube 14 has one or more apertures 25 to allow inflow of combustion air and a conventional flame holder 28.

In use, fuel from the pipe 11 enters chamber 19 and must flow, via bore 17a, conduit 22, through the heated area in the flame adjacent the end of flame tube 14 and back to bore 1 7b and chamber 18 before issuing from jet 20. Thus, if in use, liquid fuel enters conduit 22 due to tilting or inversion of the appliance, any such liquid is vaporised by the flame temperature and cannot issue from the jet nozzle 20. This feature enables an appliance such as a blow torch to be used in a tilted or inverted position without danger or misfunction. Further, appliances such as lanterns and heaters are intrinsically safer, because if they are inadvertently knocked over a stream of burning liquid gas cannot be generated.

The invention is not limited to details of the foregoing and variations can be made thereto.

For example, the conduit 22 can be wholly or partly outside the flame tube 14. Conduit 22 can loop around the flame zone if desired.

Many other variations are possible within the scope of the following claims.

Claims

1. A burner assembly including a body having an inlet for gas and an outlet jet, a burner tube extending from the body, surrounding the jet and having an aperture or apertures for the entry of air for combustion, wherein a gas flow conduit provides a gas flow path which extends from the inlet to a flame zone of the burner tube and back to the jet, to ensure that all fuel reaching the jet must pass to the flame zone and be heated above its vaporization temperature before issuing from the jet, ensuring that a liquid fuel stream cannot issue from the jet.

2. An assembly as claimed in claim 1 wherein the flame tube is integral with the body.

3. An assembly as claimed in claim 1 wherein the flame tube is attached to the body.

4. An assembly as claimed in claim 1, 2 or 3 wherein the flame tube has a flame holding formation.

5. An assembly as claimed in any preceding claim wherein the body has, internally, two separate chambers, namely an inlet chamber connected to a gas supply pipe and an outlet chamber connected to the jet nozzle.

6. An assembly as claimed in any preceding claim, wherein the gas flow conduit is in the form of a length of tubing having one of its ends connected to the inlet chamber and the other to the outlet chamber, a central portion thereof being disposed in the flame zone.

7. An assembly as claimed in claim 6 wherein the length of tubing is hairpin-shaped.

8. An assembly as claimed in claim 6 or 7 wherein the conduit is wholly within the flame tube.

9. An assembly as claimed in claim 6 or 7 wherein the conduit has its central part only within the flame tube.

10. An assembly as claimed in claim 6 wherein the central part of the conduit surrounds the flame exit orifice of the tube.

11. An assembly as claimed in any preceding claim wherein the flame tube is of overall cylindrical shape, having a part of its walling deformed outwardly to form a U-section channel accommodating a part of the conduit.

12. A gas burner assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.