GB2112674A - Modular gas burner - Google Patents

Abstract

A gas burner tube 1 is simply and effectively divided into modules separated by gas-tight seals by collapsing the tube at the required intervals 8. The collapsing is effected by the use of a pressing tool which, when the collapsing results in a flattening of the tube, may also bend the tube where it is flattened. <IMAGE>

Description

SPECIFICATION Method of manufacturing gas burners The invention relates to gas burners of the type divided into separate sections or "modules" which are separately fed with gas from a common manifold, and to methods of manufacturing same.

Hitherto, such burners have frequently suffered from leakage of gas from a module supplied with gas into an adjacent module which was not intended to be so supplied, with the result that an undesireable mixture of gas and air is produced in that adjacent burner. Moreover, the manufacture of such burners has proved difficult and it has been particularly difficult to modify the production technique to provide modules of different lengths. Additionally it has hitherto been im practicabie to produce modular gas burners other than straight.

According to one aspect of the present invention there is provided a method of manufacturing modular gas burners comprising the step of collapsing an elongate burner tube intermediate its ends to separate one portion of the tube from another and providing each portion with gas inlet means and gas outlet ports.

The collapsing of the tube is preferably effected by pressing with a pressing tool and may be effected at intervals along the length of the tube to provide the tube with a plurality of modules. The collapsing preferably is such as to bring transversely opposed portions of the wall of the tube into such close proximity as to provide a gas-tight seal between adjacent modules.

The collapsing may result from a distortion wholly or mainly of one of the transversely opposed portions or from an equal distortion of each of the portions. The transversely opposed portion may be the respectively upper and lower portions or the laterally opposite portions of the burner tube as arranged horizontally in use.

Where the tube has been collapsed, the transverse section may be rectilinear, and the tube may be bent where it is collapsed.

According to a further aspect of the invention there is provided a modular gas burner produced by collapsing an elongate burner tube intermediate its ends to separate one portion of the tube from another and providing each portion with gas inlet means and gas outlet ports.

According to yet a further aspect of the invention there is provided a modular gas burner which in at least one plane is nonrectilinear.

The invention will now be further described by way of example and with reference to the accompanying drawings of which: Figure 1 is a partial side elevation of a modular burner made by the method of the invention; Figure 2 is an end elevation of the Fig. 1 embodiment; Figure 3 is a section on lines Ill-Ill of Fig.

1; Figure 4 is a partial side elevation of a modular burner according to a further embodiment; Figure 5 is a schematic plan view of a modular gas burner which is non-rectilinear in one plane; Figure 6 is a detail of a portion of the burner shown in Fig. 5; and Figure 7 is side elevation of the portion shown in Fig. 6.

In the Figs. 1-3, a burner tube 1, originally a cylindrical stainless steel tube of approximately 25mm outside diameter and 1 mm wall thickness is flattened at its ends 2 to form a gas-tight seal, and the flat portions 4 are pierced with holes 5 for mounting screws. The tube is perforated by a series of holes 3 extending from one flat portion to the other and around a portion, less than one-half, of its circumference which in use will be uppermost.

At spaced positions between the flat portions, the tube is compressed with a tool vertically so that over a predetermined portion 8 of its length, the half of the circumference which in use is to be lowermost is pressed towards the upper half, the outer curvature of the lower half is reversed from convex to concave and the inner faces 6, 7 of the respective upper and lower halves of the tube are brought together in gas-tight sealing relationship. The pressing tool is such that at positions 9, a predetermined distance at each side of the portion 8, the tube retains its circular cross section, whilst at positions between portion 8 and positions 9, the tube is partially collapsed as shown particularly in Fig. 3.

The portions 8 of complete collapse of the tube define boundaries between adjacent modules of the burner tube between which the gas-tight relationship prevents leakage from one module which may be supplied with gas by means to be described below, and an adjacent module which may not be so supplied. For the length of the portions 8, the holes 3 which otherwise provide gas outlet ports are closed by the proximity of the inner face 7 of the lower half of the deformed tube, but in another embodiment not shown the tube may not be perforated over the portions 8.

The pressing tool is applied to the tube at spaced positions dictated by the required lengths of the modules which in turn are governed by the widths of ceramic elements or radiants 1 3 (shown for example in Fig. 4) to be supported above them. In practice, the tool will probably be designed so that with the closest likely application a sufficient length of tubing 1 of original circular section remains intermediate adjacent portions 8 so that a gas inlet tube 10 may be introduced into the tube where it is cylindrical and where the inlet tube can be welded to the burner tube most effectively. Tubes with longer modules will have correspondingly longer portions retaining their circular cross-section.

In the embodiment shown in Fig. 4, the tube is completely collapsed over a portion 8 much shorter than in the Fig. 1 embodiment, but still long enough to effect a gas-tight seal.

Adjacent the portion 8, the tube is substantially but not completely collapsed, that is to say the faces 6, 7 are closely spaced, over a length portion 11. The combined lengths of the completely and substantially collapsed portions of the Fig. 4 embodiment approximate to the length of the completely collapsed portion 8 of the Fig. 1 embodiment.

The holes 3 defining gas ports in the portion 11 are not, like those in the portion 8, closed. Because of the restricted passage between the faces 6, 7, in the portion 11 gas is able to pass out of the ports of that portion only at a much lower flow rate than at positions where the faces 6, 7 are more widely spaced. As a result, with gas supplied to module A but not to adjacent module B, the flame pattern of the radiant 1 3 may be as indicated by line 1 2. The low flame rising from portion 11 will make little difference to the appearance of the radiant 1 3 but will be of advantage in helping the ignition of gas flowing from module B if and when gas is supplied also to that module.

The burner tube shown schematically in Fig. 5 has a generally curved appearance and as such contrasts markedly with those in conventional domestic gas fires which are invariably straight because of the difficulty in bending such tubes. In fact, however, the tube of the illustrated embodiment is not truly curved but consists of five straight modules 14 linked together, each at an angle to its neighbour, by an articulation zone 1 5.

The articulation zones are formed by collapsing the tube 1 by equal distortion from both sides, as shown in more detail in Figs. 6 and 7, by the use of pressing tools acting on the tube in a horizontal direction. This results in the opposed internal surfaces 17, 1 8 coming together in gas-tight relationship and the complete flattening of the tube at positions 16.

Because of the flattening of the tube it is much more readily bent at positions 1 6 than over the portions 14, and bending is effected through an angle a at each articulation zone simultaneously with or subsequently to the collapsing by the use of appropriately shaped tools.

To one side of the position 1 6 of gas-tight relationship, gas outlet ports 1 9 lie within a zone of substantial collapse where the internal cross-sectionai area of the tube is considerably less than in the portion 1 4. Gas introduced into portion 14 by inlet pipe 20 consequently flows at a lower rate out of the ports 1 9 than out of ports 21 within portion 14, so that in use the outlets 1 9 provide a low flame suitable for ignition of gas issuing from the ports of the adjacent module.

The flattening at 1 6 is in a vertical plane, but if desired the flattening can be arranged to be in any other plane by appropriately modifying the angle of approach of the pressing tools.

According to design requirements, the burner tube 1 may be divided into two, three, four, five or more modules, and the inlet tubes 10 may be fed from a common manifold. Whilst the invention has been described as being applied to a tube of steel and of circular section, it may of course be applied to tubes of other material and other initiai crosssectional shape.

Claims (11)

1. A method of manufacturing modular gas burners comprising the step of collapsing an elongate burner tube intermediate its ends to separate one portion of the tube from another and providing each portion with gas inlet means and gas outlet ports.

2. A method according to Claim 1 wherein the collapsing of the tube is effected by pressing with a pressing tool.

3. A method according to Claim 1 or Claim 2 wherein the collapsing of the tube is effected at intervals along the length of the tube to provide the tube with a plurality of modules.

4. A method according to any one of the preceding Claims wherein the collapsing is such as to bring transversely opposed portions of the wall of the tube into such close proximity as to provide a gas-tight seal between adjacent modules.

4. A method according to any one of the preceding Claims wherein the collapsing results from a distortion wholly or mainly of one of the transversely opposed portions.

5. A method according to Claim 4 wherein the transversely opposed portions are the respectively upper and lower portions of the burner tube as arranged horizontally in use.

6. A method according to Claim 4 wherein the transversely opposed portions are the laterally opposite portions of the burner tube as arranged horizontally in use.

7. A method according to any one of the preceding Claims wherein, where the tube has been collapsed, the transverse section is rectilinear.

8. A method according to Claim 1 wherein the tube is bent where it is collapsed.

9. A modular gas burner produced by collapsing an elongate burner tube intermediate its ends to separate one portion of the tube from another and providing each portion with gas inlet means and gas outlet ports.

10. A modular gas burner which in at least one plane is non-rectilinear.

11. A method of manufacturing modular gas burners substantially as described.

1 2. A modular gas burner substantially as described with reference to Figs. 1 to 3, Figs.

1 to 3 as modified by Fig. 4, or Figs. 5 to 7 of the drawings.