GB2045419A - Gas burner - Google Patents

Abstract

A burner box 11, 12, 13, 14, for a surface burning plague 50 has a venturi tube 21 extending from one wall into the interior of the box, the bottom wall 15 of the box being formed so as to define at least a longitudinal portion of the venturi tube. <IMAGE>

Description

SPECIFICATION Gas burners The present invention relates to gas burners and is particularly concerned with the mounting of surface burning plaques.

Surface burning plaques are normally mounted on a burner box so as to form one side of the box.

The box is supplied with a gas/air mixture which perculates through the plaque to be burnt on the outerside surface of the plaque.

Normally, the box is a metal pressing and is provided with an aperture in one side which receives the neck of a venturi tube. The venturi tube is normally welded to the surrounding wall of the aperture.

The position of the outlet of the venturi in relation to the plaque affects the distribution of the gas/air mixture within the box with the consequence that an uneven flame on the surface of the plaque can result if the venturi is not correctly positioned.

Consequently, when assembling the box it is necessary for the venturi to be accurately located prior to welding. To assist in location of the venturi it has been proposed to form a projection in the bottom wall of the box. The outlet end of the venturi is rested on the projection and is then spot welded thereto. Consequently, the outlet end of the venturi is accurately located at a predetermined height above the bottom wall of the box.

The above assembly of a burner box is undesirable since even with the provision of the projection it is still necessary for care to be taken in ensuring that the axis of the venturi is substantially parallel to the side walls of the box.

Additionally, it is possible for the spot weld between the venturi and the projection to fail in use with the consequence of the venturi working loose.

According to one aspect of the present invention there is provided a burner box for a surface burning plaque, the burner box having a venturi tube extending from one wall into the interior of the box, the bottom wall of the box being formed so as to define at ieast a part of the venturi tube.

Advantageously, several burner boxes arranged side by side may be formed from a single metal pressing.

According to another aspect of the present invention there is provided a gas fire including a burner box as defined above. The gas fire may be a wall mounted gas fire or a mobile type gas fire.

Reference will now be made to the accompanying drawings, in which: Figure 1 is a plan view, partly broken away of a burner assembly according to the present invention; Figure 2 is a side view of the burner assembly shown in Figure 1; Figure 3 is an end view, partly broken away, of the burner assembly shown in Figure 1; Figure 4 is a plan view of a plaque support; Figure 5 is a sectional view along line V-V of Figure 4.

Referring initially to Figures 1 to 3 there is shown a burner assembly 10 having four side by side burner boxes 11, 12, 13 and 14 which are all formed in one-piece from a single metal pressing.

Each burner box has a bottom wail 1 5 which during the pressing operation is formed so as to define the lower half 1 8 of a venturi tube 21. The bottom wall 1 5 is also formed so as to define planar marginal portions 19, 20 extending along each side of the venturi lower half 1 8. The upper half 22 of the venturi tube which is also a metal pressing is provided with similar planar marginal portions which are secured to one another by spot welding to form a complete venturi tube. Since the position of the lower half 18 is determined during the pressing process of each burner box in relation to the upper peripheral edge portion 25 of each box, the requirement for accurately positioning the venturi tube during assembly is avoided.

The bottom wall 1 5 is also provided with an inclined portion 1 5a which extends from the base of the venturi outlet mouth 21 a up towards the upper edge portion of each box in order to provide a deflection surface for the gas/air mixture exhausting from the venturi. The deflection surface helps to encourage even distribution of the aas-air mixture throuahout the box.

The metal pressing from which the boxes 11, 12, 13 and 14 are formed also includes a pair of support flanges 30, 31 which are located at opposed ends of the boxes.

A plaque retaining member 40 is secured to support flanges 30, 31 preferably by self tapping screws 41 thereby enabling the retaining member tobe easily removed.

The holes 42 for receiving the screws 41 are preferably punched out when forming the metal pressing so that pairs of holes 42 are accurately located along the centre line of each box. Location of the holes 42 in this manner ensures that the position of the retaining member and hence the plaques retained thereby are accurately located in relation to the boxes.

The flange 31 is also provided with a depending flange 32 which is provided with a series of apertures 33 accurately positioned during the pressing process so as to be aligned co-axially with the axis of each venturi tube. Gas jets (not shown) are located in each aperture 33 and are therefore accurately positioned relative to each venturi tube.

As mentioned above, each plaque 50 is held in position above a respective box by means of the retaining member 40. A gasket (not shown) is placed between each plaque and the surrounding edge portion 25 of each box and the retaining member urges each plaque into contact with its associated gasket to form a gas tight seal.

The retaining member 40 is also a one piece metal pressing having a pair of flanges 42, 43 for securing to flanges 30, 31 respectively. The retaining member 40 also includes struts 44 which extend between flanges 42, 43 to define recessed windows for receiving the plaques. Each strut 44 is basically 'L' shaped in cross-section, one leg 44a of which defines a partition wall between adjacent plaques and the other leg 44b of which abuts against the marginal portion of the front of a plaque. Leg 44a is formed so as to have a length which gives it sufficient rigidity so as to be able to exert an even pressure on the plaques when urging them into contact with the burner boxes. Lugs 44c are also formed in struts 44 for engaging the plaque located on the side of the strut opposite to that which is engaged by leg 44b.

It will be appreciated that any number of burner boxes may be produced from a single metal pressing.

Claims (14)

1. A burner box for a surface burning plaque, the burner box having a venturi tube extending from one wall into the interior of the box, the bottom wall of the box being formed so as to define at least a longitudinal portion of the venturi tube.

2. A burner box according to claim 1 wherein the longitudinal portion of the venturi tube formed in the bottom wall of the box is bordered on both longitudinally extending sides by a planar marginal portion.

3. A burner box according to claim 2 wherein the remainder of the venturi tube is bordered on both longitudinally extending sides by a planar marginal portion which are secured to the planar marginal portions in the bottom wall.

4. A burner box according to any preceding claim wherein the longitudinal portion of the venturi tube formed in the bottom wall constitutes one half of the venturi tube.

5. A burner box according to any preceding claim wherein the burner box is a metal pressing.

6. A burner box according to any preceding claim including a depending flange spaced from said one wall, said depending flange including an aperture for receiving a gas jet, the aperture being co-axially aligned with the venturi tube.

7. A burner box substantially as described with reference to the accompanying drawings.

8. A gas burner including at ieast one burner box according to any preceding claim.

9. A gas burner according to claim 8 wherein several burner boxes are formed side by side from a single metal pressing.

10. A gas burner according to claim 9 wherein each burner box is provided with a burner plaque and a common retaining means is provided for securing the burner plaques in position.

11. A gas burner according to claim 10 wherein the retaining means includes a plurality of side by side recessed windows, each window receiving an individual plaque, the retaining means including a pair of spaced flanges for securing to the burner boxes and spaced struts extending between the flanges, each window being defined by the flanges and a pair of struts.

12. A gas burner according to Claim 11 wherein each strut in cross-section is 'L' shaped, one leg of which defines a partition wall between adjacent plaques and the other leg abuts against a marginal portion of the front of one plaque, and the struts located between two plaques also being provided with projecting lugs spaced along the strut and which abut against the front face of the plaque located on the side of the strut opposite to said one plaque.

13. A gas burner substantially as described and illustrated in the accompanying drawings.

14. A gas fire including a burner box according to any one of Claims 1 to 7.

1 5. A gas fire including a gas burner according to any of Claims 8 to 13.