GB2258909A

GB2258909A - Gaseous fuel flow control arrangement

Info

Publication number: GB2258909A
Application number: GB9118131A
Authority: GB
Inventors: Frank Gostelow
Original assignee: New World Domestic Appliances Ltd
Current assignee: New World Domestic Appliances Ltd
Priority date: 1991-08-22
Filing date: 1991-08-22
Publication date: 1993-02-24
Anticipated expiration: 2011-08-22
Also published as: GB9118131D0; GB2258909B

Abstract

A gaseous fuel flow control arrangement comprises a gas rail 1, a plurality of disc-type gas laps (7 to 10) formed integrally with the gas rail for controlling the flow of gas between a gas inlet (3) and respective gas outlets (15), and a thermostatically controlled gas tap 12 formed integrally with the gas rail 1, the thermostatically controlled gas tap 12 comprising a first part 21 mounted on the gas rail 1 and including a rotatable disc valve member 13 for controlling gas flow from the gas inlet (3), and a second pan 22 mounted on the gas rail 1 and including a thermostatically controlled unit 37 which is coupled to the first part 21 and which controls a valve member 34 and thus the flow of gas from the first part 21 to a thermostatically controlled gas outlet 19. The valve member 34 is coupled to the disc member 13 by a rod 25 and to a screw-threaded spindle 36 secured to the unit 37. Rotation of disc member 13 causes rotation of the valve member 34 with axial movement thereof relative to a valve seat 33 resulting from the screw-threaded connection with the spindle 36. The unit 37 is itself rotatable with respect to the housing of the second part 22 for calibration purposes. <IMAGE>

Description

Gaseous Fuel Flow Control Arrangements This invention relates to gaseous fuel flow control arrangements and more particularly to such arrangements for use in gas cookers and gas hobs.

In Patent No. 2165337 there is disclosed a gaseous fuel flow control arrangement in which a plurality of gas taps are provided each of which makes use of a gas rail as an integral part thereof in order to control the flow of gas between a gas inlet and respective gas outlets of said gas rail. The gas rail is provided with a machined surface on which the gas taps are located, and each gas tap is provided with a disc valve member which has a machined and contoured base which co-operates with the machined surface of the gas rail whereby when the disc valve member is rotated the flow of gas is controlled.

In gas cookers which incorporate an oven, it is necessary to provide a thermostatically controlled gas tap for controlling the oven temperature. Normally, the thermostatically controlled gas tap is assembled and calibrated as an integral unit and if it malfunctions for some reason e.g. due to damage to the temperature sensor, or capillary, it is usual to replace it with a new one. When the gas tap is formed as an integral part of a gas rail which is provided with other gas taps formed integrally with it, it is not economically viable to replace the whole gas rail should the thermostatically controlled gas valve malfunction.

It is an object of the present invention to provide a gaseous fuel flow control arrangement comprising a gas rail and a plurality of gas taps formed integrally therewith and also an improved thermostatically controlled gas tap formed integrally with the gas rail.

According to the present invention there is provided a gaseous fuel flow control arrangement comprising a gas rail, a plurality of gas taps formed integrally with said gas rail for controlling the flow of gas between a gas inlet and respective gas outlets of said gas rail, and a thermostatically controlled gas tap formed integrally with said gas rail, said thermostatically controlled gas tap comprising a first part mounted on said gas rail and including a rotatable disc valve member for controlling the flow of gas from said gas inlet, and a second part separately mounted on said gas rail and including a thermostatically controlled unit which is coupled to said first part and which controls the flow of gas from said first part to a thermostatically controlled gas outlet.

In a preferred arrangement according to the invention it may be arranged that said gas rail is of generally rectangular cross-sectional form, the first part of said thermostatically controlled gas tap being mounted on one surface thereof and the second part of said thermostatically controlled gas tap being mounted on a second surface of said gas rail which is opposed to said one surface.

In carrying out the invention it may be arranged that the rotatable disc valve member of said first part of said thermostatically controlled gas tap is in sliding contact with said one surface of said gas rail, a control member being provided for rotating said disc valve member, and it may be further arranged that the second part of said thermostatically controlled gas tap comprises a body member having a valve seat disposed between a gas inlet and a gas outlet thereof, and a valve member which is movable into and out of sealing contact with said valve seat to control gas flow between said gas inlet and said gas outlet.

Preferably, the gas inlet of said second part is disposed in a surface of said body member which is in contact with the second surface of said gas rail.

It may be arranged that the second part of said thermostatically controlled gas tap further comprises a bellows unit disposed in said body member and a fluid filled temperature sensing member external of said body member which is coupled to said bellows unit, said bellows unit being adjustably connected to said valve member.

In one arrangement a threaded spindle may be attached to said bellows unit, said valve member being in threaded engagement with said threaded spindle, said bellows unit being rotatable relative to said body member and said valve member for calibration purposes, and said valve member being rotatable relative to said bellows unit to control the thermostatic setting of said thermostatically controlled gas tap.

It may be arranged that the valve member of the said second part of said thermostatically controlled valve is coupled to the disc valve member of the said first part thereof and is rotatable therewith to control said thermostatic setting, in which case, a coupling spindle may be provided which extends through said gas rail between said valve member of said second part and said disc valve member of said first part.

An exemplary embodiment of the invention will now be described reference being made to the accompanying drawings, in which: Fig. 1 depicts a plan view of a gaseous fuel flow control arrangement in accordance with the present invention; Fig. 2 is a side view, partly in cross-section, of the arrangement of Fig. 1; Fig. 3 is a cross-sectional side view of the thermostatically controlled gas tap of the arrangement of Figs. 1 and 2; and Fig. 4 is a cross-sectional side view of a modified form of the thermostatically controlled gas tap of Fig. 3.

The gaseous fuel flow control arrangement shown in Figs. 1 and 2 of the drawings comprises a gas rail 1 which is of generally rectangular cross-section and preferably of extruded form, and which is provided along its length with a through bore 2 one end of which affords a gas inlet 3 and the other end 4 of which is blocked by means of a plug 5.

On one of the major surfaces 6 of the gas rail 1 are mounted six disc-type gas taps 7 to 12. Gas taps 7 to 10 are of the kind disclosed in GB Patent No.

2165337 and each comprise a disc valve member 13 which slidingly engages the major surface 6 of the gas rail 1, the disc valve members being rotatable by means of control spindles 14 and provided with a contoured base which acts in conjunction with holes (not shown) in the surface 6 of the gas rail 1 to control gas flow between the gas inlet 3 and respective gas outlets 15 (Fig. 2), which in use would supply gas to respective gas burners of a gas cooker or hob (not shown). The gas taps 7 to 10 are each provided with a housing member 16 by means of which it is attached to the gas rail 1. The disc taps 7 to 10 may take any convenient form.

The gas rail 1 is also provided with a disc-type grill tap 11, which may take any convenient form, which controls gas flow from the gas inlet 3 to a gas outlet 17, and a gas shut-off valve 18 of the kind described in GB Patent No. 2178519, which is normally operated by a cooker or hob lid and which, when operated, shuts off gas flow to the gas taps 7 to 10.

It should be appreciated that the gas taps 7 to 11 and the gas shut-off valve 18 have been described by way of example only and their precise form is not crucial to the present invention and, in fact, the precise form and number of disc-type gas taps 7 to 10 may be different to those shown, and the provision of the disc-type grill tap 11 and the shut-off valve 18 is optional.

The present invention is mainly concerned with the thermostatically controlled gas tap 12 which is mounted on the gas rail 1 and which is used to thermostatically control gas flow from the gas inlet 3 of the gas rail 1 to a gas outlet 19 which would supply gas to the gas burner of an oven (not shown) which would be thermostatically controlled by the gas tap 12. The gas tap 12 is provided with a fluid-filled heat sensitive phial 20, the purpose of which will be described hereinafter, but which is placed within the oven in order to sense oven temperature.

The thermostatically controlled gas tap 12 of Figs. 1 and 2 is formed in two parts, a first disc-tap part 21 which is similar in construction to the disc-type gas taps 7 to 10 of Figs. 1 and 2, and a thermostatically controlled unit 22 to which the heat sensitive phial 20 is attached by capillary tube 23 and which affords the gas outlet 19. The disc-tap part 21 of the gas tap 12 is mounted on the major surface 6 of the gas rail 1 and the thermostatically controlled unit 22 is mounted on the opposed major surface 24 of the gas rail 1. The disc-tap part 21 is provided with a coupling member 25 which extends through the gas rail 1 and engages with the unit 22 as will be described hereinafter.

In Fig. 3 of the drawings there is depicted a cross-sectional side view of the thermostatically controlled gas tap 12 of Figs. X and 2. The gas tap 12 comprises the disc-tap part 21 which is mounted on the major surface 6 of the gas rail 1, and the thermostatically controlled unit 22 which is mounted on the opposed major surface 24 of the gas rail 1.

The disc-tap part 21 of the gas tap 12 shown in Fig. 3 comprises a disc valve member 13 the under surface of which engages the surface 6 of the gas rail 1 and which is provided with a cut-out 26 which, when the disc valve member is rotated by the control spindle 14, controls gas flow between an opening 27 in the surface 6 of the gas rail which is coupled to the gas bore 2 thereof, and a vertical gas bore 28 which extends through the gas rail 1. The disc-tap part 21 is provided with the housing member 16 by means of which it is attached to the gas rail 1. The disc-tap part 21 is also provided with the coupling member 25 which engages the disc valve member 13 and rotates with it, and which extends through the gas bore 28 in the gas rail 1.

The thermostatically controlled unit 22 of the gas tap 12 of Fig. 3 comprises a body member 29 which is secured to the surface 24 of the gas rail 1 by means of retaining screws 30 (Fig. 1), with a sealing washer 31 therebetween. The body member 29 is provided with an opening 32 adjacent the flared end of the bore 28 in the gas rail 1 and with an annular valve seat 33 which is disposed between the opening 32 and the gas outlet 19 in the body member 29. The valve seat 33 is provided with a resilient, cone-shaped, valve member 34 which is movable into and out of contact with the valve seat 33 to control gas flow to the gas outlet 19. The valve member 34 is provided with a central bore 35 which at one end is internally threaded and engages with an externally threaded spindle 36.The other end of the central bore 35 in the valve member 34 is adapted to receive the end of the coupling spindle 25 so that when the disc valve member 13 is rotated, the valve member 34 is also rotated. The threaded spindle 36 is mounted on a bellows unit 37 which is secured in a mounting cap 38 which locates in a counterbore 39 in the body member 29, the edge of the counterbore 39 being peened over to secure the cap 38 to the body member 29. The threaded spindle 36 is secured to one side 40 of the bellows unit 37 and a spring 41 is provided which acts between the side 40 and the valve member 34 to urge it towards the valve seat 33. The other side 42 of the bellows unit 37 bears against the mounting cap 38 and is connected to the capillary tube 23 coupled to the heat sensitive phial 20 (Fig. 1), not shown in Fig. 3.

The thermostatically controlled gas tap 12 thus far described with reference to Fig. 3 operates as follows: With the control spindle 14 in the OFF position, the cut-out 26 in the disc valve member 13 is arranged to block any gas flow from the gas bore 2 to the central gas bore 28. In this position the heat sensitive phial 20 will be cold, and the bellows unit 37 will be in its unexpanded state in which the valve member 34 is maintained clear of the valve seat 33.

When the control spindle 14 is turned to the ON position, the cut-out 26 in the disc valve member 13 aligns with the opening 27 connected to the gas bore 2 and the central gas bore 28 and permits gas flow from the gas bore 2 through the central gas bore 28, through the opening 32 in the body member 29, past the valve seat 33 and to the gas outlet 19. The gas outlet 19 would, in use, be coupled to an oven gas burner which could then be lit in the usual way. As the oven heats up, the heat sensitive phial 20 (Fig. 1) which is disposed in the oven is caused to be heated, thereby causing the fluid in it to be expanded. As the fluid expands the bellows unit 37 is caused to expand which causes the valve member 34 coupled to it to be moved into sealing contact with the valve seat 33, thereby to cut-off the gas flow to the gas outlet 19 and thus to the oven gas burner.It is not desirable that the oven gas burner should be allowed to be completely extinguished, and to avoid this, the gas rail 1 is provided with a fixed by-pass passage 43 which effectively by-passes the valve member 34 and permits a small amount of gas to flow to the gas outlet 19 and thus to the oven gas burner, sufficient to maintain the oven gas burner alight, but not sufficient enough to cause the oven to be heated.

With the valve member 34 seated on the valve seat 33, gas flow to the gas oven is restricted so that the oven cools down, thereby allowing the heat sensitive phial 20 to cool down. As it does so the fluid in it contracts, thereby causing the bellows unit 37 to contract so that the valve member 34 is lifted from the valve seat 33, thereby restoring gas flow to the gas outlet 19. In this way the temperature of the oven is maintained thermostatically dependent upon the setting of the thermostatically controlled gas tap 12.

It will be appreciated that because of the coupling member 25, as the control spindle 14 is rotated to rotate the disc valve member 13, the coupling member 25 is also rotated and this causes the valve member 34 to be rotated. The valve member 34 is in threaded engagement with the spindle 36 so that as it is rotated, it is moved towards or away from the valve seat 33, thereby changing the thermostatic setting of the gas tap.

As is usually the case it is necessary to calibrate the thermostatically controlled gas tap described with reference to Fig. 3. This is achieved by setting the valve member 34 to a preset angular position with the phial 20 heated to a predetermined temperature. The rotary position of the valve member 34 is then maintained constant and the mounting cap 38 is rotated relative to the body member 29, which has the effect of causing the spindle 36 on which the valve member 34 is mounted to be rotated thereby causing the valve member 34 to be moved relative to the valve seat 33. The valve member 34 may thus be set as required.

It will be appreciated that unlike known forms of thermostatically controlled gas taps, the thermostatically controlled unit 22 of the gas tap 12 of Fig. 3 can be calibrated separately from the remainder of the gas tap 12 which not only helps in the assembly of the gas taps, but means that should a gas tap malfunction when incorporated in an appliance, it is a simple matter to replace the thermostatically controlled unit 22 with another such calibrated unit, thereby obviating the need to replace the whole gas rail assembly.

In Fig. 4 of the drawings there is depicted a modified form of the gas tap 12 of Fig. 3. For convenience only those parts of the gas tap of Fig. 4 which are significantly different to those of Fig. 3 will be described.

In the gas tap of Fig. 4, the fixed by-pass passage 43 provided in the gas rail 1 of the gas tap 12 of Fig. 3 is dispensed with and replaced by an adjustable by-pass passage 43 provided in the body member 29, a by-pass adjusting screw 44 being provided for adjustment purposes. This can be useful where the thermostatically controlled gas tap 12 needs to be adjusted for different gases e.g. natural gas, LPG etc.

In the gas tap of Fig. 4, the mounting cap 38 of the gas tap of Fig. 3 is dispensed with and replaced by a machined top 38' which is secured to the body 29 by means of the peened over edge of the counterbore 39, a sealing ring 45 being provided between the two.

Claims

1. A gaseous fuel flow control arrangement comprising a gas rail, a plurality of gas taps formed integrally with said gas rail for controlling the flow of gas between a gas inlet and respective gas outlets of said gas rail, and a thermostatically controlled gas tap formed integrally with said gas rail, said thermostatically controlled gas tap comprising a first part mounted on said gas rail and including a rotatable disc valve member for controlling the flow of gas from said gas inlet, and a second part separately mounted on said gas rail and including a thermostatically controlled unit which is coupled to said first part and which controls the flow of gas from said first part to a thermostatically controlled gas outlet.

2. An arrangement as claimed in claim 1, in which said gas rail is of generally rectangular crosssectional form, and in which the first part of said thermostatically controlled gas tap is mounted on one surface thereof, and the second part of said thermostatically controlled gas tap is mounted on a second surface of said gas rail which is opposed to said one surface.

3. An arrangement as claimed in claim 2, in which the rotatable disc valve member of said first part of said thermostatically controlled gas tap is in sliding contact with said one surface of said gas rail, a control member being provided for rotating said disc valve member.

4. An arrangement as claimed in claim 2 or claim 3, in which the second part of said thermostatically controlled gas tap comprises a body member having a valve seat disposed between a gas inlet and a gas outlet thereof, and a valve member which is movable into and out of sealing contact with said valve seat to control gas flow between said gas inlet and said gas outlet.

5. An arrangement as claimed in claim 4, in which the gas inlet of said second part is disposed in a surface of said body member which is in contact with the second surface of said gas rail.

6. An arrangement as claimed in claim 4 or claim 5, in which the second part of said thermostatically controlled gas tap further comprises a bellows unit disposed in said body member and a fluid filled temperature sensing member external of said body member which is coupled to said bellows unit, said bellows unit being adjustably connected to said valve member.

7. An arrangement as claimed in claim 6, comprising a threaded spindle attached to said bellows unit, and in which said valve member is in threaded engagement with said threaded spindle, said bellows unit being rotatable relative to said body member and said valve member for calibration purposes, and said valve member being rotatable relative to said bellows unit to control the thermostatic setting of said thermostatically controlled gas tap.

8. A gaseous fuel flow control arrangement substantially as hereinbefore described with reference to the accompanying drawings.

8. An arrangement as claimed in claim 7, in which the valve member of the said second part of said thermostatically controlled valve is coupled to the disc valve member of the said first part thereof and is rotatable therewith to control said thermostatic setting.

9. An arrangement as claimed in claim 8, comprising a coupling spindle which extends through said gas rail between said valve member of said second part and said disc valve member of said first part.

10. A gaseous fuel flow control arrangement substantially as hereinbefore described with reference to the accompanying drawings.

AWDHENTS TO THE CLAMS HAVE BEEN FLED AS FOLLOWS

1. A gaseous fuel flow control arrangement comprising a gas rail, a plurality of gas taps formed integrally with said gas rail for controlling the flow of gas between a gas inlet and respective gas outlets of said gas rail, and a thermostatically controlled gas tap formed integrally with said gas rail, said thermostatically controlled gas tap comprising a first part mounted on said gas rail and including a rotatable disc valve member for controlling the flow of gas from said gas inlet, and a second part which is separately mounted on said gas rail, said second part comprising a body member having a valve seat disposed between a gas inlet and a gas outlet thereof, a valve member which is movable into and out of sealing contact with said valve seat to control gas flow between said gas inlet and said gas outlet, a bellows unit disposed in said body member and a fluid filled temperature sensing member external of said body member which is coupled to said bellows unit, said bellows unit being rotatable relative to said body member and said valve member for calibration purposes, and said valve member being rotatable relative to said bellows unit to control the thermostatic setting of said thermostatically controlled gas tap.

4. An arrangement as claimed in any preceding claim, in which the gas inlet of said second part is disposed in a surface of said body member which is in contact with the second surface of said gas rail.

5. An arrangement as claimed in any preceding claim, comprising a threaded spindle attached to said bellows unit, and in which said valve member is in threaded engagement with said threaded spindle.

6. An arrangement as claimed in any preceding claim, in which the valve member of the said second part of said thermostatically controlled valve is coupled to the disc valve member of the said first part thereof and is rotatable therewith to control said thermostatic setting.

7. An arrangement as claimed in claim 6, comprising a coupling spindle which extends through said gas rail between said valve member of said second part and said disc valve member of said first part.