GB2058297A - Gas cock and a device for preventing unburned gas discharge - Google Patents

Abstract

A gas cock (2) and a valve (3), for preventing unburned gas discharge are provided in combination, side-by- side, the gas cock being arranged to be operated to open and close a gas flow by an operation shaft (1) (the "gas tap") and the valve (3) having a driving shaft (4) and a connecting means (5) operably to connect the driving shaft (4) with the operation shaft (1) so that operation of the operation shaft (1) will drive the driving shaft (4) to set the valve (3) at the same time as the gas is turned on by the gas cock (2). Extinguishing of the gas flame will cause the safety device to cut off the gas supply through the gas cock. <IMAGE>

Description

SPECIFICATION Gas cock and a device for preventing unburned gas discharge This invention relates to a combination of a gas cock and a device for preventing unburned gas discharge.

Apparatus of this kind is known in which a gas cock incorporates a device for preventing unburned gas discharge such as a safety valve, a pilot gas valve or an ignition switch for automatic ignition or the like. A conventional gas cock is also known which does not have such a device. It has been desired that this latter type of gas cock be arranged to work in conjunction with such a device so that the device can be arranged to be operable in conjunction with an operation shaft of the gas cock, as occasion demands, without requiring any special adaptation of the gas cock.

According to the present invention, there is provided an combination of a gas cock and a device for preventing unburned gas discharge, the gas cock being arranged to be operated to open and close a gas flow by an operation shaft, and said device having a driving shaft and a connecting means operably to connect said driving shaft with said operation shaft so that operation of said operation shaft will drive said driving shaft to set said device.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a sectional side view of one form of gas cock in combination with a device for preventing unburned gas discharge, Figures 2a and 2b are sectional views taken along the line 11-Il in Figure 1 for explaining the operation thereof, Figures 3a and 3b are sectional views taken along the line Ill-Ill in Figure 1 for explaining the operation thereof, Figures 4a, 4b and 4c are sectional views taken along the line IV--IV in Figure 1 for explaining the operation thereof, Figure 5 is a sectional side view of a second embodiment of gas cock in combination with a device for preventing unburned gas discharge, Figure 6 is a view similar to Figure 5 but showing a third embodiment, Figure 7 is a view similar to Figure 5 but showing a fourth embodiment, and Figure 8 is a diagram showing a modification that a part of the apparatus shown in the preceding Figures can have.

Referring firstly to the embodiment shown in Figure 1 , with reference to Figure 2 to 4 explaining the operation thereof, the gas cock 2 has a gas inlet opening 2a on one side thereof, a pilot gas outlet opening 2b on the other side for connection to a pilot burner, and a main gas outlet opening 2c at one end (its lower end as shown) for connection to a main burner. An operation shaft 1 for the cock is connected through a connector 6 at its lower end to a tapered closure 7 and the tapered closure 7 is provided therein with a pilot gas valve 9 having a valve body 8 connected to the lower end of the connector 6.By pushing-in and turning the operation shaft 1 from its closed or "off" position, the pilot gas valve 9 is opened by a downward movement of the valve body 8 caused by a downward movement of the connector 6 against the action of a spring 6a, and the tapered closure 7 is opened by the turning movement of the connector 6. These movements cause the gas inlet opening 2a to be brought into communication with the main gas outlet opening 2c through a main gas passage opening 7a in the tapered closure 7 and with the pilot gas outlet opening 2b through a pilot gas passage opening 7b in the closure 7, the opening 7b being connected through the pilot gas valve 9 to the main gas passage opening 7a. Thus, gas supplied to the pilot burner and the main burner is effected.

Additionally, at that time, an operation ball 1 0a for an ignition switch 10 provided on the outside of the gas cock 2 is so pushed outwards by a cam 6b formed on the periphery of the connector 6 as to close the switch 10, whereby the pilot burner is ignited and thus the main burner is ignited through the pilot burner.

A device for preventing unburned gas discharge, which may be a safety valve, a pilot gas valve or an ignition switch, is shown as a safety valve 3 having a gas inlet opening 3a on one side thereof and a gas outlet opening 3b on its other side, the opening 3b being in communication with the gas inlet opening 2a of the gas cock 2. The safety valve 3 contains an electromagnetic 11 at its lower end and a valve body 12 constituting a driven member is so arranged that, by a turning movement of a driving shaft 4 against the action of a return spring 4a, a valve body 12 may be given a pushing and valve opening operation against the action of a spring 1 2a.More in detail, the safety valve 3 is provided above the valve body 12 with a connector 14 having on its lower side an operation rod 13 extending from the connector 14 towards the valve body 12 so that the connector 14 can be moved downwards against the action of a spring 1 4a. Thus, by the turning movement of the driving shaft 4 against the action of the return spring 4a, the connector 14, and accordingly, the operation rod 13 may be given a downward movement through a cam mechanism 1 7 comprising a cross pin 15, which is so inserted in a slot 4b formed in the lower end of the driving shaft 4 as to be movable upwards and downwards, and a cam 1 6 which is in slidable engagement with the pin 1 5. Thus, by the downward movement of the operation rod 13, the valve body 12 is pushed downwards to its predetermined valve open position at which the same is brought into pressure contact, at its magnet attraction member 1 2b on its lower end, with the electromagnet 11. By firing of the main burner, the electromagnetic 11 is energised by the electrical output of a flame or heat responsive element such as a thermocouple, so that the valve body 1 2 is retained by the magnetic attraction in its valve open position when the main burner is alight A connecting means 5 couples operation of the gas cock 2 with the safety valve 3 and has a first connecting member 18 fixedly mounted on the outer end portion of the operation shaft 1 remote from the connector 6 and has engaging claws 18a, 18a bent downwards, and a second connecting member 19 fixedly mounted on the outer end portion of the driving shaft 4 and having, on its outer periphery, engaging recesses 19a, 19a. A turning plate 20 having on its outer periphery engaging pins 20a, 20a, which are to be brought into engagement with the engaging recesses 19a, 19a, is loosely mounted on the operation shaft 1 below the first connecting member 18.The connecting means 5 can be changed over between its operative condition, in which as a result of a downwards movement of the first connecting member 18 caused by the pushing operation of the operation shaft 1 from its closed position against the action of the spring 6a, the engaging claws 18a, 18a are brought into engagement with engaging recesses 20b, 20b on the outer periphery of the turning plate 20 and consequently the two connecting members 18, 19 are interconnected through the turning plate 20, and its inoperative condition, in which, as a result of an upward movement of the operation shaft 1 caused by the action of the spring 6a resulting from the release of pushing pressure on the operation rod 1, the interconnection between the two connecting members 18, 19 is broken.The break in the interconnection results from the upward movement of the first connecting member 18 whereby the engaging claws 18a, 18a escape upwards out of the engaging recesses 20b, 2Ob.

Numeral 20c denotes a bracket for holding the turning plate 20 in its loosely mounted condition.

The operation of the apparatus shown in Figures 1 to 4 will now be explained.

In conjunction with a push and turning operation of the operation shaft 1 from its closed position (the condition shown in Figures 2a, 3a, 4a), opening of the pilot gas valve 9 and a changeover movement of the connecting means 5 to its operative condition are given first by a downward movement of the operation shaft 1.

Then, by the subsequent turning movement of the operation shaft 1, a cock opening of the tapered closure 7 (the condition shown in Figures 2b, 3b) is given and at the same time the driving shaft 4 is given a turning movement against the action of the return spring 4a (the condition shown in Figure 4b) and consequently the safety valve 3 is opened.

Thus, the pilot burner is supplied with gas from the pilot gas outlet opening 2b of the gas cock 2 and is ignited by closing of the ignition switch 10 and, at the same time, the main burner is supplied with gas from the main gas outlet opening 2c and is fired by the pilot burner. In addition, the safety valve 3 is retained in its valve open condition by the energisation of the electromagnet 11.

If, then, the operation shaft 1 is released from the pushed condition, by an upward movement of the operation shaft 1, the pilot gas valve 9 is closed and the ignition switch 10 is opened. At the same time, the connecting means 5 is changed over to its inoperative condition, and the driving shaft 4 is given a turning back movement by the return spring 4a. Thereby, through the connector 14, the operation rod 13 is moved back upwards by the spring 1 4a while being guided by the cam mechanism 17, so that the safety valve 3 is ready to make its valve closing operation which would be caused by an accidental extinguishing of the gas flame.

Additionally, by the foregoing turning back movement of the driving shaft 4, the turning plate 20 is also turned back by the turning back of the second connecting member 1 9 attached to the driving shaft 4. The engaging recesses 20h, 20b are brought out of such positions that are just below the engaging claws 1 8a, 1 8a of the first connecting member 18 (see the condition shown in Figure 4c), so that the pushing operation of the operating shaft 1 under this condition is prevented since the engaging claws 1 8a of the first connecting member 18 are brought into abutment with the surface of the turning plate 20. In this way, the turning plate 20 serves as a stop for preventing the pushing operation of the operation shaft 1 at positions other than the closed position.

Accordingly, in the case where the ignition fails, the operation shaft 1 is required to be turned back to its closed position and thereafter a reignition operation by the pushturning thereof can be effected. Thus, a danger can be prevented by reignition immediately after the ignition failure so that residual gas is fired.

The above explains the case in which the gas cock 2 does not itself have a safety valve but is provided with the safety valve 3. However, in such a burning device having a plurality of burners, such as an oven having a burner for an upper burning region and a burner for a lower burning region, for instance, a gas cock, even if it has a safety valve, is sometime desired to be further provided with one or more safety valves, corresponding to the number of burners.

Figure 5 shows an example used in such a case, and it will be seen that the gas cock 2 has a safety valve 22 on its lower end, the safety valve 22 not being in communication with the safety valve 3.

Comparing the constructions shown in Figures 1 and 5, it will be seen that the Figure 5 construction accommodates the safety valve 22 by extending the lower end of the valve body 8 for the pilot gas valve 9 downwardly to form an operation rod 24 facing a valve body 23 of the safety valve 22.

Thus, in this case, by a push and turning operation of the operation shaft 1, the pilot gas valve 9, the tapered closure 7 and the safety valve 22 are all opened so that gas from the gas inlet opening 2a in the side of the safety valve 22 is connected with the main gas outlet opening 2c through the main gas passage opening 7a in the tapered closure 7. Communication is also made from the opening 2a to the pilot gas outlet opening 2b through the pilot gas valve 9 and the pilot gas passage opening 7b.

The safety valve 3 provided on the outside of the gas cock 2 has substantially the same construction as that shown in Figure 1. Thus, by the push and turning operation of the operation shaft 1, as before, the valve 12 is opened by the turning movement of the driving shaft 4 against the action of the return spring 4a and thus gas is supplied from the gas inlet opening 3a to the gas outlet opening 3b.

Here, the main gas outlet opening 2c in the gas cock 2 and the gas outlet opening 3b in the safety valve 3 are connected, individually, to two burners of a gas burning device and pilot gas burners of the respective main burners are connected in common to the pilot gas outlet opening 2b of the gas cock 2. Thus, by closing the ignition switch 10, which is effected during the push and turning operation of the operation shaft 1, the respective pilot burners are ignited and so the two main burners are fired and also the respective safety valves 3, 22 are kept in their valve open conditions by the flames of the respective burners supplied with gas through those valves 3, 22. When either one of the two burners is extinguished by accident, the safety valve 3 or 22 corresponding thereto is closed and consequent discharge of unburned gas from that burner is prevented.

This arrangement can be changed into such a burning condition that, by the turning back movement of the operation shaft 1, burning at the burner connected to the gas cock 2 is stopped and burning at the burner connected to the safety valve 3 is continued.

Figures 6 and 7 show two further embodiments which are similar to one another in construction and are based on the Figure 5 embodiment.

However, in the embodiments of Figures 6 and 7, the safety valves 3 and 22 are in direct communication with one another and Figures 6 and 7 show two ways of achieving this.

As can be seen, the gas cock 2 has the safety valve 22 on its lower end and the safety valve 3 to one side. The gas outlet opening 3b of the safety valve 3 is in communication with the gas inlet opening 2a of the safety valve 22. In this case, two separate gas burners of a gas burning device are connected in common to the main gas outlet opening 2c of the gas cock 2 and the respective safety valves 3, 22 are retained in their valve open conditions by the flames of the respective burners.

Thus, when either one of the two burners is extinguished by accident, the safety valve 3 or 22 corresponding thereto is closed so that the gas supply to the two burners is cut out.

Consequently, the danger that unburned gas discharged from the burner which has been extinguished might be exploded by the flame of the other burner can be prevented.

The connecting means is not limited to that shown in the foregoing examples and may be modified as shown, for example, in Figure 8. In this Figure, the second connecting member 1 9 is formed with an L-shaped slot 25 for insertion of the first connection member 1 8. In this case, the connecting means 5 may be changed over between an operative condition and an inoperative condition by a pushing operation of the operation shaft 1 from its closed position, where the first connecting member is in one end of the L-shaped slot 25 and releasing the connection by causing the first connecting member 18 to be moved upwards and sidwards (as viewed in Figure 8) along the horizontal slot portion 25b of the L-shaped slot 25, this portion serving as a stop 21 for preventing the pushing operation of the operation shaft 1 at positions other than its closed position.

In the above examples, it has been shown that only a single device 3 constituting a safety valve is provided on the outside of the gas cock 2 but the gas cock 2 may be provided with two or more such safety valves around its outside.

Furthermore, in the case of a gas cock which does not have the pilot gas valve 9 or the ignition switch 10, the device 3 can comprise such a pilot gas valve or an ignition switch and it may also comprise a changeover valve or a timer or the like, as occasion demands.

Thus, the device 3 can be arranged to be operable in conjunction with the operation shaft 1 of the gas cock 2 without requiring any special work on the gas cock 2.

Claims (11)

1. A combination of a gas cock and a device for preventing unburned gas discharge, the gas cock being arranged to be operated to open and close a gas flow by an operation shaft, and said device having a driving shaft and a connecting means operably to connect said driving shaft with said operation shaft so that operation of said operation shaft will drive said driving shaft to set said device.

2. A combination as claimed in claim 1, wherein the gas cock is opened by a push and turning operation of said operation shaft.

3. A combination as claimed in claim 1 or 2, wherein said device is operated by a turning movement of said driving shaft against the action of a resilient bias.

4. A combination as claimed in claim 1,2 or 3, wherein said connecting means has first and second connecting members which are respectively attached to outer end portions of said operation shaft and said driving shaft, respectively, said connecting members being releasably engageable with one another.

5. A combination as claimed in claims 1 to 4, wherein said connecting members transmit rotary motion of said operation shaft to said driving shaft when said operation shaft is pushed and turned, the connection being released upon release of pushing pressure, whereafter said driving shaft is turned back to its original position by said resilient bias.

6. A combination as claimed in claim 5, wherein said connecting means is provided with a stop which is operated by reverse rotary movement of said second connecting member caused by release of connection between said connecting members, said stop serving to prevent, by its abutment with said first connecting member, pushing of said operation shaft at positions other than the gas closed position of said gas cock.

7. A combination as claimed in any one of preceding claims, wherein said device is a gas safety valve.

8. A combination as claimed in claim 7, wherein said safety valve includes a cam mechanism to convert rotary movement of said driving shaft into reciprocal movement for driving a rod against a resilient bias, said rod acting on parts to open and close gas flow through the safety valve, there being means to hold said rod to allow gas to flow through the safeW,valve only when a flame of a pilot gas burner or a main gas burner is alight.

9. A combination as claimed in claim 8, wherein a further safety valve is provided, this safety valve being incorporated in said gas cock, the two safety valves not being in communication with one another.

10. A combination as claimed in any one of claims 1 to 9, wherein a further safety valve is provided, this safety valve being incorporated in the gas cock itself, the two safety valves being in communication with one another.

11. A combination of a gas cock and a device for preventing unburned gas discharge, substantially as hereinbefore described with reference to any one of the embodiments shown in the accompanying drawings.