GB2327749A

GB2327749A - Gas fired heaters

Info

Publication number: GB2327749A
Application number: GB9715732A
Authority: GB
Inventors: Donald Whitehouse
Original assignee: Valor Heating Ltd; Valor Ltd
Current assignee: Valor Heating Ltd; Valor Ltd
Priority date: 1997-07-26
Filing date: 1997-07-26
Publication date: 1999-02-03
Anticipated expiration: 2017-07-26
Also published as: GB9715732D0; GB2327749A8; GB2327749B; CA2244307A1

Abstract

The present specification discloses a gas fired heater having a control lever (13) (Fig.1) which is movable to open a flame failure valve (53,59) and a main gas supply valve (49,50). The main gas supply valve (49, 50) is connected to at least one burner (5,7) (Fig.5) by a thermostatically controlled valve (71) and/or, when two or more burners are provided, via a preselector valve (75).

Description

DESCRIPTION IMPROVEMENTS RELATING TO GAS FIRED HEATERS The present invention relates to a gas fired heater.

More particularly, the present invention relates to a gas fired heater of the type used to heat open spaces in a private dwelling, office, hotel or restaurant, with the heater including a simulated solid fuel bed comprising simulated coals and/or logs.

The aim of the present invention is to provide a gas fired heater with an easy to use and versatile control.

According to the present invention there is provided a gas fired heater comprising a control lever which is movable to open a flame failure control valve and a main gas supply valve, the main gas supply valve being connected to at least one gas burner.

In a preferred embodiment of the present invention the control lever is manually operable and is a vertically arranged elongate rod, the upper end region of which is bent at right angles and projects through a gate-like aperture in the front fascia of the heater, towards the upper region of the heater. The lower end region of the elongate rod extends into a housing within which the flame failure control valve and the main gas supply valve are located, and is connected to a valve control plug. Rotation of the elongate rod about its longitudinal axis by movement of the bent upper end region of the rod, across the gate-like aperture, rotates the valve control plug so that a passage extending through the plug from the base thereof to an upper side wall region connects the region within the housing below the plug with a pilot burner outlet. Axial movement of the control rod by depressing the upper end region which projects through the gate-like aperture, moves the control rod downwards through the plug to open the flame failure control valve, gas flowing through the said passage in the plug to the pilot burner outlet which is connected to a pilot burner. The downward axial movement of the control rod causes a cam on the control rod to activate a micro-switch which is connected to an ignition unit, gas issuing from the pilot burner being thus ignited.

As per usual this pilot flame heats a thermocouple which is connected to a solenoid of the flame failure valve, the solenoid holding the flame failure valve open when the thermocouple has attained a sufficiently high temperature to produce the required e.m.f to hold the solenoid.

With the flame failure valve held open by the solenoid the elongate control rod can be released to move upwards under spring force, the plug having further passages which were aligned with a main burner outlet when the plug was initially rotated, and which now connect the space below the plug with a main burner outlet. This main burner outlet preferably connects with one or more main burners via a thermostatically controlled valve which preferably can be manually overridden, the pilot flame igniting the required main burners. Thus whilst the thermostatically controlled valve can automatically adjust gas flow therethrough dependent upon the temperature of the surroundings, this valve can preferably be manually adjusted as desired. In a preferred construction part of the perimeter of a manually operable control knob projects through part of the gate-like aperture allowing the control knob to be rotated to adjust the thermostatically controlled valve.

As an alternative to manual operation, the control lever may be controlled electrically via a suitable solenoid and/or motor drive.

Further, a preselector valve is preferably located between the thermostatically controlled valve and the main burners, so that the gas supply can be fed to the desired burner or selection of available main burners.

This preselector valve may be manually or electrically operable, and such a valve may be formed by a number of individual pulse valves, one for each burner. Each pulse valve may be of the battery operable type wherein an electrical pulse switches the valve to an open position or to a closed position.

Additionally pulse valves which determine high or low gas flow rates, may be located between the burners and the preselector valve, to enable easy adjustment of two possible burner settings for each burner.

The present invention thus provides an easy to use gas fired heater with the heater being turned off by rotation of the upper end region of the elongate control rod, this rotation engaging a further microswitch which disconnects the solenoid from the thermocouple so that the flame failure valve closes under spring action, shutting off the gas supply, the pilot and the main burners being thus extinguished.

Further, rotation of the elongate control rod rotates the plug to thus disconnect the passages therethrough from the pilot and main burner outlets. Thus, the gas supply is positively disconnected, avoiding the possibility of gas leakage should the spring action of the flame failure valve fail, or some other consequence e.g. dirt, prevent the flame failure valve from completely closing.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a partially cutaway front view of one embodiment of a gas fired heater constructed according to the present invention; Fig. 2 is a schematic perspective view of the combined flame failure control valve and the combined main gas supply valve used in the embodiment of Fig. 1; Fig. 3 is a schematic cross sectional view of the combined valve of Fig. 2; Fig. 4 is a cross sectional view of the control plug used in the combined valve of Figs. 1 to 3; and Fig. 5 is a diagrammatic illustration of a modified form of the burner control system shown in Fig. 1.

One embodiment of a gas fired heater 1 constructed according to the present invention is illustrated in partially cutaway section in Fig. 1 of the accompanying drawings. The heater 1 is a simulated solid fuel effect gas fired heater for heating open spaces in a private dwelling, restaurant or the like. The heater 1 has a simulated fuel bed comprising simulated logs 3 between and below which are located two main burners 5,7. Alternatively only one burner or more than two burners can be provided. Located adjacent to said main burners 5,7 is a pilot burner 9.

A combined flame failure control valve and main gas supply valve, generally designated 11 is located in the lower, right hand part of the heater 1, and controls the gas supply to the main burners 5,7 and to the pilot burner 9. This combined valve 11 is best understood with reference to Figs. 2, 3 and 4 of the accompanying drawings, and is controlled by elongate control rod 13, the upper end region 15 of which is bent at right angles to project through a gate like aperture 17 in the front fascia of the heater (see Fig.

1). The lower end region 19 of the elongate control rod 13 extends into the housing 21 of the combined valve 11 and is connected to a control plug 23.

As seen in Fig. 3, the control plug 23 has a passage 25 extending therethrough which can connect the space 27 below the plug 23 with a pilot burner outlet 29. Also the plug 23 has an axially extending passage 31 (see Fig. 4) through which a reduced dimension part 33 of the control rod 13 extends, a shoulder 14 being formed between part 33 and the remainder of rod 13.

The plug 23 has a hollow cylindrical projection 38 extending upwards from the upper surface of the plug, with the control rod 13 being an axially slidable close fit therein. A spring 37 is located around the reduced diameter part 33 of the control rod 13, the spring 37 engaging against shoulder 14 and against an annular washer 39 which is located above a flexible O-ring seal 41, the O-ring seal 41 resting in the upper region of passage 31 on a reduced diameter region 43 of passage 31. The reduced diameter part 33 is thus slidably and sealingly located in the O-ring seal 41. A further 0ring seal 45 is secured at a lower position on said part 33 between two laterally extending, annular retaining sections 47 of the said part 33, the radially outer extremities of this further O-ring seal 45 projecting beyond said retaining sections 47 and sealingly engaging the wall of passage 31. The lower region of passage 31 has a lateral port 49 which can connect with a main burner outlet 50 in the combined valve housing 21.

In use the upper end region 15 of control rod 13 is first moved sideways across the gate-like aperture 17, from a left off-position to a right on-position, this rotation of control rod 13 rotating the plug 23 to align passage 25 with the pilot burner outlet 29, and lateral port 49 with main burner outlet 50. Then the upper end region 15 of the control rod 13 is depressed ie moved downwards in the gate-like aperture, the control rod compressing spring 37 so that O-ring seal 41 is compressed and further seals against the reduced diameter part 33 of the control rod, as the control rod slides therethrough. This downward movement also moves the further O-ring seal 45 below the lateral port 49 so that the main burners 5,7 are disconnected from space 27 below the plug 23, with the lower end 51 of the control rod then engaging and forcing downwards a closure member 53 of the flame failure valve 55, against a spring 57. The closure member 53 is thus lifted off its seat 59 so that gas supplied via inlet 61 can pass to space 27, through passage 25 to the pilot burner 9.

During this downward movement of the control rod 13 a microswitch 63 (see Fig. 2) is tripped energising an ignition unit 65 so that the gas issuing from the pilot burner 9 is ignited. The flame of the pilot burner heats a thermocouple 67 in the usual manner, and when a sufficient temperature has been attained, the e.m.f. produced by the thermocouple will hold a solenoid 69 of the flame failure valve, in the open position ie. the closure member 53 will be maintained in the open position. Then by merely releasing the upper end region 15 of the control rod 13, the control rod 13 moves upwards under the action of spring 37 with further 0-ring seal 45 being moved above lateral outlet 49. Thus gas can then flow from space 27 via passage 31 and lateral port 49, to the main burners 5,7.

When the heater is to be turned off, the upper end region 15 of the control rod 13 is moved sideways in the gate-like aperture 17, from the right hand onposition to the left hand off-position. This movement rotates the control rod about its longitudinal axis so that a cam 13' trips a further microswitch 13'' to disconnect the solenoid 69 from the thermocouple 67 causing the flame failure valve 55 to close under the action of spring 57, thus cutting off the gas supply.

Also, the control plug 23 is rotated so that the passage 25 is moved out of alignment with the pilot burner outlet 29, the lateral outlet 49 being also moved out of alignment with the main burner outlet 50.

Thus the plug 23 positively closes off the gas supply, avoiding any possibility of gas leakage should spring 57 fail or the closure member 53 not seat properly due to, for example, the presence of dirt entrained in the gas flow.

With the combined valve operative, the pilot burner being ignited so that the flame failure valve 55 is held open and the control rod released, gas flows through the main burner outlet 50 to a thermostatically controlled valve 71 which controls the gas flow to main burners 5, 7 dependent upon the surrounding temperature. This thermostatically controlled valve 71 can be manually overridden using a rotatable control 73, part of which projects through the gate-like aperture 17. Thus, once ignited, the operation of the heater can be automatically and manually controlled, as desired.

The gas flows from the thermostatically controlled valve 71 to a preselector valve 75 which is manually operable to select one or other, or both main burners 5, 7, as desired. Thus the desired flame configuration/heat output can be selected.

In a modified heater illustrated diagrammatically in Fig. 5 pulse valves 77 are provided between the preselector valve 75 and the main burners 5, 7. These can be omitted as can the preselector valve, if desired. These pulse valves are battery operated with an electrical pulse being sufficient to switch a valvefrom a high throughflow rate to a low throughflow rate.

Thus at the mere push of a button or flick of a switch, the gas flow rate to a particular burner can be changed to vary the flame configuration and/or heat output, as desired. Further, the manually operable preselector valve 75 can be replaced by a pulse valve with an "on" or "off" characteristic as opposed to a "high" or "low" flow rate characteristic. Alternatively any other suitable electrically operated valve or valves can be substituted for the or each pulse valve.

The present invention thus provides a gas fired heater with simple, though versatile and positive control.

Claims

1. A gas fired heater comprising a control lever which is movable to open a flame failure valve and a main gas supply valve, the main gas supply valve being connected to at least one gas burner.

2. A gas fired heater as claimed in claim 1, in which the control lever is a vertically arranged elongate rod, which has an upper end region which extends laterally of the remainder of the rod and projects through an aperture in the upper region of the front of the heater.

3. A gas fired heater as claimed in claim 1 or claim 2, in which the control lever in the form of an elongate rod, has a lower end region which extends into a housing and is connected to a valve control plug, the flame failure valve and the main gas supply valve being located in said housing.

4. A gas fired heater as claimed in claim 3, in which the elongate rod is connected to the valve control plug so as to be axially movable relative thereto, though rotatable therewith, the rod extending through an axially extending passage in the plug and being axially movable therethrough against a spring to engage and move a closure member of the flame failure valve.

5. A gas fired heater as claimed in claim 4, in which a seal is provided on the elongate rod, said seal engaging the wall of the passage extending axially through the plug, and being located so that when the elongate rod is moved axially to engage and move the closure member of the flame failure valve, the seal disconnects a main burner outlet port provided in the wall of the passage in the plug, from the lowermost portion of said passage, the flame failure valve and a main gas supply passage.

6. A gas firred heater as claimed in claim 5, in which a further passage extends through the plug and is arranged to connect a space below the plug with a pilot burner outlet passage in said housing, when said plug is in a rotational position wherein the main burner outlet port in the plug is aligned with a main burner supply passage in the housing.

7. A gas fired heater as claimed In any one of claims 3 to 6, in which the control plug is tapered and located in a complimentarily tapered cavity in the housing.

8. A gas fired heater as claimed in any one of claims 2 to 7, in which a microswitch connected in an ignition circuit is arranged to be tripped by axial movement of said elongate rod.

9. A gas fired heater as claimed in any one of claims 2 to 8, in which a further microswitch connected to a solenoid of the flame failure valve is arranged to be tripped by rotational movement of the elongate rod.

10. A gas fired heater as claimed in any one of the preceding claims, in which the main gas supply valve is connected with at least one burner via a thermostatically controlled valve.

11. A gas fired heater as claimed in claim 10, in which a manually operable override is provided for the thermostatically controlled valve.

12. A gas fired heater as claimed in claim 10, in which an electrically operable override is provided for the thermostatically controlled valve.

13. A gas fired heater as claimed in any one of the preceding claims, in which a preselector valve is located between the main gas supply valve and at least one burner.

14. A gas fired heater as claimed in claim 13, in which the preselector valve is manually operable.

15. A gas fired heater as claimed in claim 13, in which the preselector valve is electrically operable.

16. A gas fired heater as claimed in claim 15, in which the preselector valve is in the form of a number of pulse valves which can be switched between an open position and a closed position.

17. A gas fired heater as claimed in any one of claims 13 to 16, in which a pulse valve which can be electrically switched between high and low gas flow rates is located between the preselector valve and the or each said burner.

18. A gas fired heater constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.