GB1585160A

GB1585160A - Gas burner

Info

Publication number: GB1585160A
Application number: GB4176376A
Authority: GB
Original assignee: U FAB Ltd
Current assignee: U FAB Ltd
Priority date: 1977-10-04
Filing date: 1977-10-04
Publication date: 1981-02-25

Description

(54) GAS BURNER (71) We, U-FAB LIMITED, a British Company formerly of 28 Beaumont Road, Totton, Southampton, Hampshire, and now of Romsey Industrial Estate, Greatbridge Road, Romsey, Hampshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a gas burner and particularly, but not exclusively, to a gas burner for use with a water heater.

According to the present invention there is provided a gas burner comprising an air inlet chamber, a mixing chamber, valve means for controlling air flow from. said air inlet chamber into said mixing chamber, means for supplying a gaseous fuel to said mixing chamber, a combustion region located downstream of the mixing chamber and separated therefrom by a perforated plate through which a mixture of air and gaseous fuel can flow into said combustion region from the mixing chamber, and means provided in the combustion region for igniting the air/fuel mixture, said mixing chamber being provided with a restricted passage through which the air supplied from the air inlet chamber passes and downstream of said passage is a ring of jet apertures through which gaseous fuel flows into the mixing chamber.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through the gas burner, Figure 2 is a view on one end, and Figure 3 is a view on the other end.

The burner comprises an air inlet chamber 10 formed between an end plate 11 and a plate 12 which is provided with an axially extending annular wall 13. The end plate 11 has an air inlet 14 which in use of the burner receives air from a fan, not shown. The annular wall 13 is provided with slots 15. Located within the annular wall 13 is an annular valve member 16 which can be rotated relative to the wall 13. The valve member 16 having slots 17 which can be readily aligned with the slots 15 to allow air from the chamber 10 to flow to a chamber 18 formed by the member 16. The chamber 18 is closed at one end by a cover plate 19.

The plate 12 has a tapered bore 20 through which the air inlet chamber 18 communicates with a mixing chamber 21 formed within a member 22. The member 22 has a radial flange 23 which carries an axial flange 24 which forms one wall of an annular chamber 25 and is provided with an inlet 26 which can be connected to a source of gaseous fuel under pressure.

Mounted on the member 22 is an annular member 27 provided with a plurality of radially extending jet apertures 28 through which gaseous fuel can flow from the chamber 25 into the mixing chamber 21.

The apertures 28 are located immediately downstream of the bore 20. The bore 20 produces a venturi effect so that the air flowing therethrough will create a suction effect in the region of the apertures 28 to assist in drawing the gaseous fuel into the mixing chamber 21.

The downstream end of the member 22 carries a perforated flame plate 29 which is retained by a ring 30 and a flame retention tube 31 is carried by the member 22 and extends beyond the flame plate 29.

Extending across the bore 20 and fixed to the plate 12 is a carrier bar 32 which supports a probe 33, a pilot tube 34 and a spark electrode 35. The probe 33, tube 34 and electrode 35 all extend through the plate 29 into a combustion region 36 located within the tube 31.

The burner is bolted to a mounting plate 37 provided at one end of a heat exchange tube 38 of a water heater, not shown.

The valve member 16 is provided with a tab-like portion 39 which can be moved in a slot 40 provided in the cover plate 19 in order to control the air flow through the slots 15 and 17.

The gas burner may be operated automatically by a suitable control system. Air from a fan is caused to flow into the inlet chamber 10 and through the slots 15 and 17 into the chamber 18 and then through the bore 20 into the mixing chamber 21, this air then flowing through the perforations in the plate 29 into the zone 36 and along the heat exchange tube 38. This flow of air is sensed by means (not shown) and after a purge period the spark electrode 35 is energised followed by a pilot gas valve (not shown) opening which allows gaseous fuel to pass through the pilot tube 34 into the combustion region 36. This gaseous fuel is ignited by the spark electrode 35 and a stable flame is then produced which is sensed by the sensing electrode 33.Then the control (not shown) will energise the main gas valve (not shown) which opens to allow gaseous fuel to flow through the inlet 26 into the chamber 25. The gaseous fuel then flows through the jets 28 into the chamber 21 where it is mixed with the airflow. The mixture of air and gaseous fuel then flows through the apertures in the plate 29 into the region 36 where it is ignited by the pilot flame. The gas flow to the pilot tube 34 is then cut-off.

The probe 33 will cause the burner to be cut-off if there is no flame present in the region 36. The probe 33 operates on the ionisation principle.

The gaseous fuel may be supplied to the chamber 25 under high pressure, i.e. a pressure greater than that used for normal domestic supply.

WHAT WE CLAIM IS:- 1. A gas burner, comprising an air inlet chamber, a mixing chamber, valve means for controlling air flow from said air inlet chamber into said mixing chamber means for supplying a gaseous fuel to said mixing chamber, a combustion region located downstream of the mixing chamber and separated therefrom by a perforated plate through which a mixture of air and gaseous fuel can flow into said combustion region from the mixing chamber, and means provided in the combustion region for igniting the air/fuel mixture, said mixing chamber being provided with a restricted passage through which the air supplied from the air inlet chamber passes and downstream of said passage is a ring of jet apertures through which gaseous fuel flows into the mixing chamber.

2. A gas burner as claimed in claim 1, in which the air inlet chamber is an annular chamber surrounding the upstream end of the mixing chamber, the annular wall dividing the chambers being provided with a plurality of circumferentially spacedapart axially-extending slots and said valve member comprises an annular member coaxial with the annular wall and rotatable relative thereto, said annular valve member being provided with a plurality of circumferentially spaced-apart axially-extending slots which can be radially aligned with the slots provided in the annular wall.

3. A gas burner as claimed in claim 1 or claim 2, in which the combustion region is formed within a flame retention tube connected to the downstream end of the burner.

4. A gas burner as claimed in any preceding claim, including an axially extending pilot tube for supplying starting gaseous fuel directed to the combustion region.

5. A gas burner as claimed in any preceding claim, including a spark electrode which extends through the perforated plate into the combustion region.

6. A gas burner as claimed in any preceding claim, including a flame sensing probe which extends through the perforated plate into the combustion region.

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

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

from a fan is caused to flow into the inlet chamber 10 and through the slots 15 and

17 into the chamber 18 and then through the bore 20 into the mixing chamber 21, this air then flowing through the perforations in the plate 29 into the zone 36 and along the heat exchange tube 38. This flow of air is sensed by means (not shown) and after a purge period the spark electrode 35 is energised followed by a pilot gas valve (not shown) opening which allows gaseous fuel to pass through the pilot tube 34 into the combustion region 36. This gaseous fuel is ignited by the spark electrode 35 and a stable flame is then produced which is sensed by the sensing electrode 33. Then the control (not shown) will energise the main gas valve (not shown) which opens to allow gaseous fuel to flow through the inlet 26 into the chamber 25.The gaseous fuel then flows through the jets 28 into the chamber 21 where it is mixed with the airflow. The mixture of air and gaseous fuel then flows through the apertures in the plate 29 into the region 36 where it is ignited by the pilot flame. The gas flow to the pilot tube 34 is then cut-off.

The probe 33 will cause the burner to be cut-off if there is no flame present in the region 36. The probe 33 operates on the ionisation principle.

The gaseous fuel may be supplied to the chamber 25 under high pressure, i.e. a pressure greater than that used for normal domestic supply.

WHAT WE CLAIM IS:- 1. A gas burner, comprising an air inlet chamber, a mixing chamber, valve means for controlling air flow from said air inlet chamber into said mixing chamber means for supplying a gaseous fuel to said mixing chamber, a combustion region located downstream of the mixing chamber and separated therefrom by a perforated plate through which a mixture of air and gaseous fuel can flow into said combustion region from the mixing chamber, and means provided in the combustion region for igniting the air/fuel mixture, said mixing chamber being provided with a restricted passage through which the air supplied from the air inlet chamber passes and downstream of said passage is a ring of jet apertures through which gaseous fuel flows into the mixing chamber.
2. A gas burner as claimed in claim 1, in which the air inlet chamber is an annular chamber surrounding the upstream end of the mixing chamber, the annular wall dividing the chambers being provided with a plurality of circumferentially spacedapart axially-extending slots and said valve member comprises an annular member coaxial with the annular wall and rotatable relative thereto, said annular valve member being provided with a plurality of circumferentially spaced-apart axially-extending slots which can be radially aligned with the slots provided in the annular wall.
3. A gas burner as claimed in claim 1 or claim 2, in which the combustion region is formed within a flame retention tube connected to the downstream end of the burner.
4. A gas burner as claimed in any preceding claim, including an axially extending pilot tube for supplying starting gaseous fuel directed to the combustion region.
5. A gas burner as claimed in any preceding claim, including a spark electrode which extends through the perforated plate into the combustion region.
6. A gas burner as claimed in any preceding claim, including a flame sensing probe which extends through the perforated plate into the combustion region.
7. A gas burner substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.