US1711430A - spencer - Google Patents

Description

April 30, 1929. J, A, SPEN ER 1,711,430

PILOT CUT-OFF FOR GAS BURNERS Filed Sept. 16, 1927 Patented Apr. 30, 1929.

UNITED STATES PATENT OFFICE.

JOHN A. SPENCER, OF REVERE, MASSACHUSETTS, ASSIGNOR TO SPENCER THERMO- STAT COMPANY, OF CAMBRIDGE, MASSACHUSETTS,

CHUSETTS.

A CORPORATION OF MASSA- PILOT CUT-OFF FOR GAS BURNERS.

Application filed September 16, 1927. Serial 30.219338.

This invention relates to controlling means for gas consuming devices and more particularly to an automatic safety cut on associated with the main burner or pilot, 1f one 18 used, for cutting off the supply of gas in the event that the main burner and pilot flame are both extinguished.

Heating by gas 18 now very common for water heaters, stoves, furnaces and certain types of automatic refrigerators and it is cus-- tomary to vary and in some cases cut oil the heat appliedby automatic or manually controlled devices, the burners being often rela tively inaccessible. For the purpose of insuring the continuous automatic action of burners of this character, it is customary to provide a pilot to relight the main burner when necessary, although the pilot need not be used if the controlling means is adapted merely to regulate the height of the flame of the main burner. It sometimes happens in th s latter case that the flame in the main burner is accidentally extinguished, or, in the case where a pilot is used and the mam burner is intentionally extinguished, the pilot also goes out; so that when the flow of gas to the mam burner is reestablished, it is not igmted, but escapes to the surrounding parts of the bullding in which the burner is located with the attendant risks to the occupants both from fire and asphyxiation.

Among the objects of the present invention, therefore, are to provide an automatlc control or safety device responsive to the temperature of the pilot, if one is used, or to the temperature in the heated zone in which the gas is burned, which will function quickly and in a certain manner to cut oil" the entire flow of gas both to the main gas burning devices and to the pilot, if one is used, in the event that the flame is accidentally extinguished; to provide for manually relighting the main burner and pilot without the necessity of first warming the thermostat, and in this connection to provide a device in. which entirely automatic at the lowest temperature at which the thermostatic element chan s shape thus obviating the delay in relighting the burner due,to the hysteresis of the thermostatic element as well as the inertia of the moving parts; to provide in a device of this character an arrangement whereby the main valve may be located away from the high heat zone surrounding the burner consequently making it more durable and less likethe operation is again ly to get out of order; to provide a sim le yet eificient apparatus for mounting the t ermostatic element so as to protect it from extreme heat and yet permit it to be sensitively responsive to important changes of temperature; to provide a means for introducin air to mix with the gas in the pilot if one 1s used; and geperally to improve devices of this charac er.

Other objects and advantages of the invention will be apparent from the following specification and appended claims when taken in connection with the accompanying drawings, in which:

Figs. 1 and 2 are central sections on the line 7 A-A in Fig. 3 showing the valve opened and closed respectively;

Fig. 3 is a section on the line 33 in Fi 2;

Fig. 4 is a fragmentary section substantlally on the line 44 in Fig. 2'; and

Fig. 5 is a fragmentary section on a large scale showing a detail of construction.

The device comprises a valve casing I having .a gas inlet opening 2 and an outlet open-. mg 3, A valve seat 4 is provided between the so openings 2 and 3, which cooperates with a valve generally indicated at 5. This valve is mounted upon a shaft 6 extendin through the sides of the valve housing 1 am? provided at the outside with a suitable handle 7 by 86 which the valve may be opened. A tension spring 8 is preferably provided between a point 9 on the valve and a suitable point within the valve casing tending to close the valve. Any suitable valve construction may be used, but I have shown a sup orting member 10 having an aperture 11 therein to receive a block 12, which is held in place by .a. screw bolt 13, the bolt 13also holding metal washers 14 and 15 having therebetween a resilient member 16 which may be of rubber, leather or other suitable material, the member 16 being adapted to engage the edges of the valve seat 4 to out 01f the gas supply.

I provide a means for holding the valve in its open position comprising a latch 17 pivoted to a rod 18 which is suitably mounted in the casing 1, the latch havin a forwardly extending hook portion 19 adapted to engage over a shoulder 20 integral with the valve 5. The latch 17 is also provided with an abutting portion 21 adapted to be engaged b a portion 22 integral with the valve 5 so 1; at when the valve is opened by rotating the handle 7, the latch will be rotated in a clockwise 1 0 direction, as seen in Figs. 1 and 2 and the hook portion 19 engaged over the shoulder 20 and hold the valve in its open position.

A tubular member 23 is slidably mounted in a cover 24'which is screwed to the casing 1 by two or more screws 25 and also in a plug 26 screwed into the interior of the casing 1, this member being provided at its inner end with a pin 27 which is adapted to bear against the latch 17 to rotate it to release the valve 5 when the tubular member is moved to its right-hand position, shown in Fig. 2. The outer end of the tubular member is provided with a constricted passage 28 serving as a pilot flame opening. The tubularmember is made in two portions 29 and 30 telescoping together and clamping between them a bimet'allic thermostatic disk 31, later to be described, these members being fastened together in any suitable manner, as for example by a pm 31 passing through the telescoping partsof both members. The member 30 is provided with a diametrical elongated slot 32 into which protrudes the upper end of a gas nozzle member 33, which is suitably fixed to the valve housing 1 and is provided with a bore 34 extending from its lower end to a point adjacent to the top thereof, and a radial bore 35 opening into the bore 34 and aligned with the bore 36 in the member 30. The bore 34 is enlarged as by counterboring and internally threaded at its lower end, as shown at 37, for the reception of needle valve 38. A duct 39 extends through the lower wall of the valve housing 1 and the side wall of the nozzle member 33, and connects the outlet side of the valve with the lower end of the bore 34. The plug 26 is threaded into the valve housing 1, as shown at 40, and separates the gas chamber at the right-hand side of this plug, as seen in Figs. 1 and 2, from an air chamber 41, which communicates with the atmosphere in any suitable manner, as for example by a port 42.

From the above description, the operation of the pilot will be obvious. The bore 39 communicates with the main gas supply at the outlet side of the valve and conducts the gas to the inside of the nozzle member 33 where its flow is controlled by the needle valve 38, thence through the bores 34 and 35 to the bore 36 in the member 30, air entering at this point which comes in through the bore 42 and is drawn in and mixed with the gas by aspirating, and the mixture then goes through an aperture in the center of the thermostatic disk 31 and thence through the outlet opening 28 of the pilot and serves there to lgnite the main burner whenever this action is necessary. v

I provide means for mounting the thermostatic disk to permit it to flex one way or another according to the temperature to which it is subjected. This means may comprise a pair of cupped members 43 and 44, the member 43 having two or more ears 45 adapted to be clamped between the cover member 24 and the valve housing 1, and the member 44 having bent over flanges or ears 46 clam ing it to the member 43. Between the mem rs 43 and 44 I provide an annular spacing ring 47 whose internal diameter is slightly greater than the diameter of the disk 31 and whose thickness is slightly (e. g. .005) greater than that of the disk whereby free motion of the disk is permitted. As. previously stated the disk is held in position by bein clamped between members 29 and 30, a s oulder being formed upon member 29 cooperating with the end of member 30.

The disk 31 is preferably bimetallic, being formed of two component disks welded together, the materials such as iron and brass of the respective disks having different coeflicients of expansion. The disk 31 is normally cupped (as by swaging) in such direction that the component part having the higher coefficient of expansion is on the concave side. Consequently upon raising the temperature of the disk the unequal expansion of the materials forming the disk will cause a tendency to flatten the cupped surface until at a predetermined temperature a.

sudden curving in the opposite direction occurs, which reversal of shape will be maintained until the temperature has been substantially lowered. Thereafter upon reaching a substantially lower temperature, the disk will suddenly return to its initial shape. The materials and thickness of the component parts and the degree of curvature are so chosen that the disk will snap in one direction when heated to the desired temperature (e. g. 120 F.) and will snap back at a lower temperature (e. g. 100 F.). Suitable materials are sheet brass and nickel steel having a thickness of .005 and .005inches respectively and suitable cupping for a disk inches in diameter is .02 inches.

It will be understood however that the presentinvention is not limited to any particular combination of materials having different thermal coefiicients of expansion but is intended to embrace in its scope any combination of materials having dissimilar thermal coeflicients of expansion sufiicient to cause the reversal of curvature. Furthermore, the two materials comprising the composite thermostatic disk may be secured together in any desired manner by riveting, soldering, brazing, or otherwise although it is preferred to unite the materials comprising the disk by welding or similar means to secure a substantially indivisible sheet.

The operation of the thermostatic portion of the device is as follows: when the pilot is lit at the end of member 29, heat is transmitted along this member to the disk, and in the event that the pilot is not used the transmission of heat takes place through a solid member corresponding to member 29 from the highly heated zone around the main burner to the disk as well as through the walls 7 to of the valve casing member 24 to the eriphery of the disk, in either case maintaining it in the position shown in Fig. 1, that is convex to the left; and the latch 17 retains b the valve 5 in its open position. However if the flame goes out and the diskcools to a predetermined temperature, it will abruptly reverse its concavity and snap to the position shown in Fi 2, thus pushing the rod 27 to the right, lifting the latch 17, and permitting the valve tion of aspring 8.

When it is desired to again open the valve, the handle 7 is turned which opens the valve and in so doing brings the portion 22 thereof against the abutting member 21 of the latch, thus rotating the latch to lock the valve in open position, as seen in Fig. 1, and simultaneously pushing the rod 27 and the hollow member 23 to the left and flexing the disk back to its hot position, seen in Fig. 1. The burner may then be lit, but as in all thermostatic safety cut-offs, the handle to reset the valve at its open position must be held until the thermostat has reached its critical temperature. However, due to the fact that the link connectin and the valve operates in bot directions and resets the thermostat at its hot position the loss of time in holding the thermostat in position between its low critical temperature when it turns from hot to cold position, and

its high critical temperature, from cold to hot, is saved as well as the loss of time incident to heating the thermostat to a point where the forces therein are suflicient to overcome the inertia of the various moving parts of the device.

From the fore oing it will be obvious that one of the mem ers 43 and 44 holding the thermostatic disk may be omitted leaving only a single member having an annular groove at its periphery in which the spacing ring 47 and the disk 31 are received.

As many modifications may be made in this device without departin from the spirit of the invention, I do not WlSh to be limited except by the scope of the appended claims.

I claim:

1. In a gas burner controlling device, a valve ada ted to cut off the flow of gas to the burner, a latch engaging said valve normally to hold it in an open position, a bimetallic burner flame and to move said latch to permit the valve to close when the flame is extinguished and the disk cools to a predetermined temperature, and manually operable means for opening the valve and simultaneously forcing said thermostatic disk into its hot position.

2. In a gas burner controlling device, a

saidvalve to closewhen the 5 to be closed by the acl the thermostat b valve adapted to cut off the flow of gas to the burner a latch engaging said valve normally hold it in an open position, a gas pilot, a bimetallic disk thermostat having its center fixed to the tube of said gas pilot and adapted to receive heat therefrom and means engaged y said disk to trip said latch and permit pilot is extinguished and the disk cools to a predetermined temperature.

3. In a gas burner controlling device, a valve adapted .to cut ofl" the flow of gas to the burner, means tending to close said valve, a atch engaging said valve normally to hold it in an open position, a gas pilot, a thermostatic element which is perforated for the passage of gas to said pilot, means for conducting gas to said element and thence to said pilot, the pilot being bodil movable with said element, and means inc uding a part of the gas conduit to said element for actuating said latch to release the valve when the pilot is extinguished and the thermostat cooled to a predetermined temperature the parts being so constructed and arranged that opening the valve forces said element into its hot position.

4. In a gas burner controlling device, a valve adapted to cut ofl the flow of gas to the urner, means tendingto close said valve, a latch engaging said valve normal] to hold it in an open position, a substantia ly tubular member movably mounted in the valve casing having a pilot jet opening at its outer end, means fixed to the inner end of said tubular member for actuating said latch, a thermostatic element having a portion rigid with said tubular member and adapted to move it longitudinally in response to changes in temperature thereof, a duct fixed with respect to said valve casing for conductin gas to said tubular member, the duct exten ing through an elongate "slot in said tubular member and having an aperture in line with the bore thereof, whereby the latch is released by the action of the thermostatic element moving said tubular member and thus'permitting the valve to close when the pilot is extinguished 'and the thermostat cools to a predetermined temperature, and manually operable means for opening said valve, the parts bein so constructed and arranged that opening t e valve moves the latch the tubular member and the thermostatic element to their hot position.

5. In a gas burner controlling device, a

valve adapted to cut oil the flow of gas to the r disk thermostat adapted to be heated by the b and to which it is fixed, a duct extending from the outlet side of said valve and fixed with respect to said valve casing for conducting gas to said tubular member, the-duct extending through an elongate slot in said tubular member and having an aperture in line with the bore thereof, whereby the latch is released by the action of the thermostatic disk moving said tubular member and thus permitting the valve to close when the pilot is extinguished and the thermostat cools to a predetermined temperature, and manually operable means for opening said valve, the valve having an integral abutment cooperable with a protruding portion of said latch so that when the valve is opened the latch is rotated to engage it and also to move said tubular member to flex said disk to its hot position.

'6. In a pilot cut-off mechanism for gas burners, a tube having a pilot jet at one end thereof, a pair of cupped members surrounding said tube and in heat conducting relation therewith, one of said members having a pcripheral flange adapted to overlap the periphery of the other member to hold them together, a bimetallic disk thermostat, an annular spacing ring separating the edges of said members, said ring having an internal diameter slightly greater than the thermostatic disk and a thickness slightly greater than said disk, the disk being mounted between said members with its center free, a main gas supply valve, and means cooperating with said disk for closing said valve if the thermostat cools below a predetermined temperature.

7. A mounting for a bimetallic disk thermostat comprising a pair of on ped members fastened together at their peripheral edges, and an annular ring separating said members near their peripheries, said ring having an internal diameter slightl greater than the thermostatic disk and a t ickness slightly greater than said disk, the disk being loosely mounted between said members.

8. A thermostat comprising a snap-acting element which moves abruptly from one position to another when the temperature varies and a holder for said element having opposing surfaces on opposite sides of the element spacedapart a distance slightlygreater than thethickness of said element, thereby to permit the element freely to snap from one position to another.

9. A thermostat comprising a snap-acting disk which moves abruptly from one'posion opposite sides of the disk interengaging over the periphery of the disk with an annular space thcrebetween to receive the periphery of the disk and a ring surrounding the disk in said space, the thickness of the rin being slightly greater than the thickness 0 the disk, whereby the disk is free to snap from one position to another.

11.. A thermostat comprising a snap-acting I disk which moves abruptlyfrom one position to another when the temperature varies, a support for the disk including members on opposite sides of the disk, one of the members being bent over the periphery of the disk and over the other member with an annular space therebetween to receive the periphery of the disk, and a ring surrounding the disk in said space, the thickness of the ring being slightly greater than the thickness of the disk, whereby the disk is free to snap from one position to another.

Signed by me at Cambridge, Mass, this 15th day of September, 1927.

i JOHN A. SPENCER.

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