GB2302170A

GB2302170A - Plaque for use in gas burners

Info

Publication number: GB2302170A
Application number: GB9611868A
Authority: GB
Inventors: Kulwant Mandir
Original assignee: Valor Ltd
Current assignee: Valor Ltd
Priority date: 1995-06-10
Filing date: 1996-06-07
Publication date: 1997-01-08
Also published as: GB9611868D0; GB9511817D0

Abstract

A plaque (1) for use in a gas burner has a surface (5) within which a number of burner ports (7) are formed. A raised wall (13) is provided around and/or across the surface (5) to provide stability for the flames which are, in use, located above such ports (7).

Description

DESCRIPTION IMPROVEMENTS RELATING TO PLAOUES FOR USE IN GAS BURNERS The present invention relates to a plaque for use in a gas burner.

In particular the present invention relates to a plaque for use in a gas-fired heater. Such plaques are commonly constructed from a ceramic material as a rectangular block having a generally planar face in which a large number of burners ports are provided.

Each burner port opens into a burner passage which extends through the plaque, the burner passages being parallel to each other and opening into what is usually a gas/air mix chamber located under the plaque.

In use gas/air mix passes along the burner passages in the plaque and burns above or contiguous to the respective burner ports, the heat of the flames heating the plaque which then serves as a radiant heater. Such surface burning plaques have been used for many years to provide relatively high levels of radiant heat from gas energy sources. However, to comply with the combustion requirements of various Official Government Standards, it is necessary for such plaques to be designed and used such that the gas energy being burnt for a particular plaque size, is closely controlled. Normally an increase in gas/pressure in a correctly running plaque often does not create the problem of poor combustion. However a reduction of a few percent can give serious combustion problems.

An aim of the present invention is to provide a plaque with a wider acceptable operational band of parameters.

According to the present invention there is provided a plaque for use in a gas burner, the plaque comprising a surface within which a plurality of burner ports are formed, a raised wall being provided around and/or across said surface.

A typical known plaque, during use, draws air to the centre of a generally planar surface of the plaque, for combustion purposes and in so doing, creates a draught at the edges of the generally planar surface of the plaque causing the flames at the burner ports adjacent to the edge ports, to lift and give poor combustion. However, the raised edge wall of the present invention, which is adjacent to the edge ports protects the flames at these edge ports, from the draught as the flames tend to burn in the valley formed between the edge wall and the edge ports.

Further, as the flames play on the raised wall further flame stability is achieved. Also the raised wall becomes hot and adds to the radiant heating effect.

If the plaque of the present invention is located generally horizontally, the raised wall will have an advantageous effect all around the edge of the burner port region. If however the plaque is generally upright then of course the top row of burner ports will not be influenced by a draught as the combusted products will be moving upwards over this region.

However the side and bottom edge ports will be advantageously affected by the raised wall of the present invention.

Whilst the burner ports in the plaque of the present invention may be flush with the said surface of the plaque, at least some of the burner ports may have a raised lip to provide for a particular flame construction. The raised wall is then preferably higher than the raised lip of said burner ports.

Further, the burner ports and the burner passages extending therefrom, through the plaque itself, may have different diameters, ports and passages of like diameters being arranged in a regular or irregular pattern, and especially located adjacent to the raised wall, to improve flame stability.

In a further embodiment of the present invention at least one raised wall may be provided across the surface of the plaque either in addition to or in place of the raised edge wall referred to hereabove.

This raised wall or walls will divide the surface into smaller regions and have the same advantageous effect as discussed hereabove with regard to flame stability, better combustion, resultant more efficient heating of the plaque and resultant enhanced radiant performance.

The raised wall may be formed integrally with the plaque or be formed by a separate structure bonded to or otherwise secured to the plaque.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of one embodiment of the present invention; and Fig. 2 is an enlarged perspective view of a cutaway corner section of the embodiment of Fig. 1.

A plaque 1 constructed according to the present invention is shown in Figs. 1 and 2 of the accompanying drawings. The plaque 1 is made of a ceramic material and is in the form of a generally rectangular block or slab 3. The block 3 has an upper generally planar surface 5 on which a plurality of burner ports 7 are formed, each burner port 7 leading to a burner passage 9 which extends completely through the block 3. The burner passages are parallel to each other and certain burner ports 7 have a lip 11 which is raised above the said surface 5.

Around the edge of the block 3 a raised wall 13 is provided, this raised wall 13 protecting the burner ports 7 in the edge region of the block 3 - see Fig.

2. Whilst the raised wall 13 is integral with the block 3, in an alternative embodiment (not illustrated) the raised wall is a separate structure bonded to or otherwise secured to the block 3.

To explain, with a known plaque and the plaque of the present invention, air is drawn towards the centre region of the said surface 5 during use, for combustion purposes. Thus a draught is produced at the edge regions of the plaque causing the flames in the known plaque, in the edge regions of the plaque, to lift and give poor combustion. In contrast, the raised wall of the present invention serves to at least reduce the effect of the draught, the flames burning in the valley formed between the raised wall and the burner ports in the edge region of the plaque.

Further, the flames in the edge region of the plaque of the present invention, heat the raised wall causing it to get hot, further flame stability being thus achieved.

In a further embodiment (not illustrated) of the present invention further raised walls, integrally formed or secured as separate structures, are provided across the said surface 5 dividing the surface into smaller regions and enhancing flame stability in these smaller regions as discussed hereabove with regard to the raised wall of Figs. 1 and 2.

The present invention thus provides an improved plaque for use in a gas burner, specially in a gas fired heater, the improved plaque providing better flame stability over the area of the plaque, and thus enhancing the efficiency of heating of the plaque, and the resultant radiant performance.

Claims

1. A plaque for use in a gas burner, the plaque comprising a surface within which a plurality of burner ports are formed, a raised wall being provided around and/or across said surface.

2. A plaque as claimed in claim 1, in which the or each raised wall is formed integrally with the surface of the plaque.

3. A plaque as claimed in claim 1, in which the or each raised wall is formed as a separate structure which is secured to the surface of the plaque.

4. A plaque as claimed in any one of claims 1 to 3, in which the burner ports are flush with the surface of the plaque.

5. A plaque as claimed in any one of claims 1 to 3, in which at least some of the burner ports have a raised lip.

6. A plaque as claimed in claim 5, in which the raised wall is higher than the said raised lip.

7. A plaque as claimed in any one of the preceding claims, in which raised walls are provided to divide said surface into a number of smaller regions.

8. A plaque as claimed in any one of the preceding claims, in which a number of different diameter burner ports are provided on said surface.

9. A plaque for use in a gas burner, constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.