US2315959A

US2315959A - Safety shutoff device for gas valves

Info

Publication number: US2315959A
Authority: US
Publication date: 1943-04-06
Anticipated expiration: 1960-04-06

Description

April 1943- J. H. G. HORSTMANN 2,315,959

SAFETY SHUT-OFF DEVICE FOR GAS VALVES Filed Sept. 11, 1941 Fig.1.

2 Sheets-Sheet l 4 V //vl/E/YTOR. 15 7 J/{Q//06T/VM/V/V.

April 6, 1943.

J. H. G. HORSTMANN SAFETY SHUT-OFF DEVICE FOR GAS VALVES Filed Sept. 11, 1941 2 Sheets-Sheet 2 33 ,8 12: i 1 30 34- v 6 i Patented Apr. 6, 1943 2,315,959 SAFETY SHUTOFF DEVICE. FOR GAS VALVES John Hermann Gustav Horstmann, Bath, England Application September 11 In Great Britain 2 Claims.

This invention relates to safety shut-off devices for gas valves feeding a main burner or burners f the kind incorporating a cut-off valve operable by a thermo-sensitive element, such as a bi-metal bow which, when cold, tends to maintain said valve in its closed position and wherein there is provided a by-pass or subsidiary burner, the flame of which is adapted to heat the said thermo-sensitive element, with a view to opening the cut-off valve and thereby permitting the passage of gas to the main burner of the appliance. An arrangement of this kind is generally preceded by a main tap operable manually or by time-controlled or other automatic mechanism.

Safety shut-off devices of the foregoing kind are intended to prevent unignited gas from escaping should the gas flame of the main burner become accidentally extinguished or should any ignition device which may be attached to the apparatus fail to operate upon the gas being turned on.

According to the present invention there is associated with the thermo-sensitive element a subsidiary burner having for its sole function the application of initial heat to the element for a predetermined time period sufficient to bring about the opening of the safety valve, said subsidiary burner being associated with automatic means adapted to extinguish its flame when this function has been fulfilled. The continuance of heat for maintaining the thermo-sensitive element in its valve-opening condition is provided for either by the contiguity of the flame from the main burner or by a separate continuously burning by-pass burner method of igniting the first mentioned subsidiary burner may be automatic (e. g. by means of an electro-catalytic filament), by a permanently burning igniting flame fed by a suitable by-pass, or by an applied match flame or the like.

An advantage of a safety shut-01f device according to the invention is that the said subsidiary burner may have a comparatively intense flame and thus whilst the controlled valve would be opened thereby very speedily, the said flame is not sustained to the detriment of the thermosensitive element. Once the valve is opened the element may be kept in its valve-opening condition by a less intense heat from the source or sources mentioned. The converse is also the case, i. e. as the intense flame useful for opening the valve quickly has been automatically extinguished after completing this function, and a less degree of heat is employed for maintaining the valveopen position, cooling-ofi of the parts on cessation of heat and consequent shutting of the valve is also a comparatively quick process.

One way of carrying out the invention is shown, by way of example, in the accompanying drawings wherein:

Figure 1 is an elevation;

or by both, and the I 1941, Serial No. 410,472 January 15, 1940 Figure 2 is a plan;

Figure 3 is a view similar to Figure 1, but with the subsidiary non-continuously burning burner omitted for clearness.

Figure 4 is a longitudinal sectional view of the safety valve.

Figure 5 is an enlarged sectional view through the control means for the momentarily acting subsidiary burner.

Referring to the drawings, the numeral l designates generally a safety valve controlled by the devices according to the invention. This safety valve I has a valve member 2 (Figure 4), the valve spindle 3 of which passes through a tube 4 fixedly mounted in the body of the valve l A bimetal bow 5 constitutes the thermo-sensitive element, and its legs are secured respectively to the valve spindle 3 and fixed tube 4. When the bow 5 is heated it opens the valve member 2, in this case by pushing the valve spindle 3 into the tube 4 and lifting the valve member 2 ofi its seating, to permit gas to pass from the inlet side 6 to the outlet side I and thence to the main burner 8.

Associated with the safety valve 1 is a main control tap 9, and in the embodiment illustrated (being provided with automatic ignition) it is merely necessary to open and close the main tap 9 to light and extinguish the main burner 8.

Referring now more particularly to the safety control of the valve member 2, there are employed in combination two auxiliary burners, one being the subsidiary non-continuously burning burner l0, and the other the continuously burning burner H. The former, I9 is adjusted to give a comparatively intense flame for speedily heating up the how 5 and opening the valve member 2, and the latter I! is adjusted to give a less intense flame which may be just sufiicient to maintain the bow 5 at a requisite temperature for maintaining the valve member 2 in its open condition.

The subsidiary burner ill for providing the non-continuous initiating flame may be served by a pressure-operated igniter appliance such as described for example in prior U. S. Patent No. 2,065,972. The effect of such an igniter appliance is that when the main tap 9 is opened the gas passing through the igniter will automatically cause the by-pass flame at H! to be ignited, the thermo-sensitive device to be operated and the main burner 8 to be lighted. whereupon the by-pass flame at Hi becomes extinguished. In this case the arrangement is such that the cutofi valve member 2 controlled by the thermosensitive device remains open under the action of the heat of the additional by-pass burner ll. said burner H being fed either from a point l5 between the main tap 9 and the cut-off valve member 2 as shown, or, if desired from a point between the valve member 2 and the outlet 1.

The operation of the embodiment described is as follows: The main tap 9 is turned on whereupon gas flows to both burners IE) and l and the pressure serves to ignite the burner l5! automatically (as fully explained in the aforesaid prior specification) and at the same time shuts off the burner l9 after a predetermined time interval. The burner H! has meanwhile ignited the burner l l, heated the bow 5, opened the valve member 2, and ignited the main burner 8. The valve member 2 will remain open so long as the burner continues alight. Should the main burner 8 become extinguished accidentally it will re-light from the burner I i, but should the latter become extinguished the how 5 will cool and the valve member 2 close.

Figure 5 of the drawings illustrates an igniter appliance of the type disclosed in prior Patent No. 2,055,972, for controlling the subsidiary burner i0. This appliance comprises a casing l2 having primary and secondary gas chambers, designated as and H, respectively, separated by a partition IS in which is a port i9 controlled by a valve 28. Defining the outer sides of the chambers H3 and I? are flexible diaphragms 2| and 22, respectively, to the former of which the valve 26 is attached, said valve being normally open and be ing movable to a position closing the port I!) by outward flexure of the diaphragm 2| under the influence of gas under pressure admitted to the chamber Hi.

The diaphragm 22 is provided at its outer side with a contact stud 23 for cooperation with a second contact stud 24 mounted on an insulating support 25 fixed to the casing [2. A leaf spring 25 tends constantly to flex the diaphragm 22 inwardly and thus tends constantly to separate the contact stud 23 from the contact stud 24. When, however, gas under pressure is admitted to the chamber ii the diaphragm ll is flexed outwardly and the contact stud 23 thereby is moved into engagem cut with the contact stud 24. A dry cell 25 is contained in a casing l4 depending from the support 25 and has one terminal thereof suitably connected with the contact stud 23 and its other terminal connected by a conductor 21 with one side of a. suitable electrical ignition device, designated generally as 28, disposed with respect to the burner it so as to be operable, when energized, to ignite gas supplied to said burner. A conductor 29 connects the other side of the ignition device 28 with the contact stud 24. The contact studs 23, 24 thus constitute a switch in the circuit between the dry cell 26 and the ignition device 28 for controlling said circuit.

Outwardly of the diaphragm 2| is an enclosed space 36 which is in communication with the atmosphere through a vent orifice 31 the effective area of which may be regulated by a manually adjustable valve 32. Thereby the rate of outward flexure of the diaphragm 2| under the influence of gas under pressure admitted to the chamber l6 may be predetermined to the end of predetermining the time period required for closing of the valve when gas under pressure is admitted to said chamber IS.

A pipe 33 connects the chamber IS with the valve I at a point between the main tap 9 and the valve member 2 and a pipe 34 connects the chamber l! with the burner 10.

The diaphragms 2| and 22 being normally in inwardly flexed positions and the valve 20 thereby bein normally open and the contact stud 23 thereby being normally spaced from the contact stud 24, opening of the main tap 9 with consequent supply of gas under pressure to the chamber It results in gas being supplied. through the port l9 and the chamber F to the burner l0 and in reasonably quick outward flexure of the diaphragm 22 with consequent closing of the switch comprised by the contact studs 23 and 24. The circuit of the ignition device 23 thereby is closed and the gas issuing from the burner i0 is ignited, with consequent quick heating of the thermal element 5 and opening of the valve member 2. At th same time, the flame from the burner H3 ignites the burner I. The burner I continues to burn until the valve 29 is closed by delayed ou ward flexure of the diaphragm 2|, whereupon the gas supply to said burner is cut on and remains out ch until the gas pressure in the chamber I6 is relieved by closing of the main tap 9. However, the burner continues to burn and to act upon the thermal element 5 to maintain the valve member 2 open, but if said burner H then is extinguished the thermal element 5 cools and closes said valve member 2.

I claim:

1. In a gas burning appliance, a main burner, a gas supply line for said burner, a main valve in said gas supply line for controlling flow of gas to said burner, a thermally operable valve in said gas supply line between said main valve and said main burner for controlling flow of gas to said main burner, a thermosensitive element operatively connected to said thermally operable valve and operable when heated to open said thermally operable valve and when cool to close said thermally operable valve, an auxiliary burner mounted adjacent to said thermo-sensitive element in a position to direct its flame when lighted to apply intense heat to said thermo-sensitive element to quickly heat the same and thereby cause the same quickly to open said thermally operable valve, a gas supply tube for said auxiliary burner connected with said gas supply line between said main valve and said thermally operable valve, control means for said auxiliary burner interposed in said gas supply tube and including means whereby it is operable by the supply of gas thereto to ignite said auxiliary burner and then to cut off the supply of gas thereto and thereby extinguish the same after the elapse of a brief predetermined period of time, and a second auxiliary burner separate from said first mentioned auxiliary burner and having a gas sup-ply connection with said gas supply line between said main valve and said thermally operable valve, said second mentioned auxiliary burner being intended to burn constantly and being mounted in a position relative to said thermo-sensitive element to apply a small non-damaging amount of heat to said thermosensitive element sufficient to cause the latter to maintain said thermally operable valve open, said thermo-sensitive element thereby being operable to close said thermally operable valve to cut on the supply of gas to said main burner upon extinguishment of said second mentioned auxiliary burner and consequent cooling of said thermo-sensitive element.

2. A gas burning appliance as set forth in claim 1 in which the first mentioned auxiliary burner is mounted in a position relative to said second mentioned auxiliary burner to direct its flame when lighted to effect lighting ol'said second mentioned auxiliary burner should the latter be extinguished.

JOHN HERMANN GUSTAV HORSTMANN.