GB2510173A - Reduced noise burner - Google Patents

Abstract

A gas burner 10 has an internal cavity 20 for receiving a gas and air mixture. A porous cylindrical distributor 18, 44 surrounds the cavity and a porous flame-strip 16, 42 coaxially surrounds the distributor. The cylindrical distributor and flame-strip are joined together at one end of the cylinder at discrete locations 60 (tabs) around the cylinder and a gap is provided between the cylinder and flame-strip. The distributor tabs 60 may be mounted to the flame strip by welding, and four tabs may be provided which may be integral with the distributor. The gap between the cylinder and flame strip provides a fluid bypass which helps to avoid noise during burning.

Description

Gas Burner This invention relates to a gas burner, and particularly but not exclusively to a gas burner for use in domestic heating appliances.

The burner may be of the "premix" type, meaning that all the air required for combustion is mixed with a fuel gas prior to burning.

This invention relates to burners of the type which include a cavity for receiving a gas and air mixture, a cylindrical distributor surrounding the cavity with relatively large through holes therein. A cylindrical flame strip surrounds the distributor, with a plurality of relatively small through holes therein defining flame ports through which the gas and air mixture may pass immediately prior to combustion.

In some instances it is required to provide a restrictor tube which is a tube of a smaller diameter which extends coaxially within the distributor for part of the length thereof. Restrictor tubes can help to alleviate noise in gas burners.

According to one aspect of the present invention there is provided a gas burner, the gas burner including an internal cavity for receiving a gas and air mixture, a distributor in the form of a cylindrical wall surrounding the cavity with a plurality of through holes in the wall, a flame strip in the form of a cylindrical wall coaxially surrounding the distributor, with a plurality of through holes in the wall of the flame strip, an external mounting flange being provided at one end of the cavity, the mounting flange being formed by the walls of the flame strip being turned outwardly at said one end to form an annular flange, with the cylinder and flame strip being joined together at said one end of the cylinder at a plurality of discrete locations spaced around the cylinder, with a gap being provided between the cylinder and flame strip at said one end other than at the discrete locations.

A tab may be provided at each discrete location on the distributor.

Each tab may include a part which extends at least generally parallel to the flame strip and can be mounted thereto.

In one embodiment the tabs are mounted to the flame strip by welding.

In other embodiments the tabs are mounted to the flame strip by interengaging formations on the tabs and flame strip. The interengaging formations may include an opening in a one of the tabs and flame strip, and a projection on the other of the tabs and flame strip, which projection once passed through an opening cannot be passed back thereoutof.

The discrete locations may be equispaced around the distributor. In one embodiment four discrete locations are provided.

The burner may also include a restrictor tube in the form of a cylindrical wall coaxially located in the distributor and extending for pad of the length thereof from said one end.

The burner may also include an end cap at the other end thereof, which end cap closes the flame strip and distributor. The end cap may be mounted on the other end of the flame strip by folding pad of the end cap over the end of the flame strip.

The distributor and/or flame strip may be formed from shaped sheet metal, and a mechanical join may be provided between ends of the sheet material to form the cylindrical shape.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:-Fig. 1 is a diagrammatic perspective view of a conventional burner in place within an appliance; Fig. 2 is a diagrammatic partially cut away perspective end view of a burner according to the inventions; Fig. 3 is a diagrammatic perspective cut away view of part of the burner of Fig. 2; and Fig. 4 is a diagrammatic cut away side view of part of the burner of Fig. 2; Fig. 1 shows by way of illustration a gas burner 10 located within a heating appliance including a combustion zone 12 and heat exchanger 14.

The gas burner 10 includes a cylindrical flame strip 16 with a concentric inner distributor 18, enclosing an internal cavity 20. An end cap 22 is attached to the flame strip 16 and closes one axial end of the gas burner 10. A mounting flange 24 is attached to the other axial end of the flame strip 16 and extends radially outwardly therefrom. The gas burner 10 is attached to a housing 26 via the mounting flange 24.

The flame strip is provided with through holes in the form of flame ports 32, just a few of which are shown in Fig. 1. The flame ports are about 1mm in diameter, and their centres are about 2 -3mm apart. The flame ports 32 are arranged evenly over the flame strip 16. The distributor 18 is provided with a regular pattern of larger through holes 28.

In use, a gas and air mixture is passed into the cavity 20 and passes through the holes 28 in the distributor 20, and out through the flame ports 32 and into the combustion zone 12 where burning takes place. The heat thereby produced is utilised via the heat exchanger 14, with the flue products passing out of the unit as indicated by the arrow A. Figs. 2 to 4 show a gas burner 40 according to the invention. The burner 40 comprises a flame strip 42, with a distributor 44 located therein. A mounting flange 46 is provided at one end of the burner 40, with an end cap 48 at the opposite end.

The flame strip 42 comprises a cylindrical wall 50 with a plurality of openings therethrough which form flame parts, but are not shown in the drawings. The openings, flame ports, in the flame strip 42 may be in a uniform pattern, or could for instance vary along the length of the flame strip 42. The openings may be circular and/or in the form of slots.

The flame strip 42 may be made from a strip of material, and a mechanical joint 52 may be provided at each end of the strip to enable the strip to be formed into the cylinder shown. The mechanical formation may be in the form of a plurality of tabs axially spaced alternately on each end which overlap respectively inside and outside of the cylinder to hold the flame strip in its configuration.

The distributor 44 is also of cylindrical form with through holes 54 formed in a cylindrical wall 56. The distributor 44 may be formed in a similar fashion to the flame strip 42 from a sheet of metal, with a mechanical fastening to retain the distributor 44 in a cylindrical configuration.

The mounting flange 46 is provided by the cylindrical wall 50 of the flame strip being turned outwardly at the one end to form the integral mounting flange 46.

The distributor 44 extends to a short distance from the one end of the flame strip 42 where the mounting flange 46 is provided. A small outwardly turned flange 58 is provided round the one end of the distributor 44. Four equispaced tab members 60 extend from the flange 58 spaced from each other, with a gap between each tab member 60 of significantly greater extent than the width of each tab member 60.

Each tab member 60 comprises a first part 62 extending outwardly from the flange 58 turning in to a second tab part 64 extending parallel to and adjacent part of the inner side of the flame strip cylindrical wall 50. Each of the tab parts 64 is mounted to the inner side of the cylindrical wall 50. In this instance the tab parts 64 are mounted to the wall 50 by spot welding.

Other types of mounting can however be used. For instance mounting portions may be provided on the tab 64 and wall 50, and these may comprise a projection on a one of the tab parts 64 or wall 50 extendable through an opening in the other, with the projection being such that it cannot pass back through the opening. It may be that the projection can be deformed to pass through the opening, or after passing through the opening so as to prevent withdrawal of the projection through the opening.

It is to be realised that there is therefore provided a gap between the one end of the distributor 44 and the flame strip cylindrical wall 50, except where the tab members 60 are provided.

This therefore provides a gas burner which only requires three components, namely the flame strip 42, distributor 44, and end cap 48. The flame strip 42 and distributor 44 can be mounted together readily by welding and particularly spot welding, or by a mechanical mounting as outlined above.

Only requiring three components provides for a cost saving relative to previous more complicated arrangements. The gap between the lower end of the distributor and the flame strip provides a bypass and helps to avoid noise during burning.

Various other modifications may be made without departing from the scope of the invention. As indicated different mounting techniques or formations could be used. A different number and/or spacing of tabs could be provided around the distributor.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.