US1953446A

US1953446A - Control mechanism

Info

Publication number: US1953446A
Application number: US673864A
Authority: US
Inventors: Strong Archie Hugh
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-06-01
Filing date: 1933-06-01
Publication date: 1934-04-03
Anticipated expiration: 1951-04-03

Description

Ap 3, 1934. A. H. STRONG CONTROL MEcHANIsM Filed June 1, 11933 l l l,

Patented Apr. 3, 1934 yCONTROL MECHANISM` Archie Hugh Strong, Conshohocken, Pa.

Application June 1, 1933, Serial No. 673,864

Claims.

'I'his invention relates to control mechanism for appliances such as water heaters employing gas for a heating medium.

One of the primary objects of my invention is the provision of improved and simplified valve mechanism for controlling the heating medium of water heaters and the like employing a pilot, both, by the temperature of the liquid being heated and by the temperature in the region' of the 10 pilot.

Another object of my invention relates to improved valve mechanism'for controlling the heating medium of water heaters and the like in which service control of the valve is afforded through means responsive to the temperature of the liquid being heated and safety or emergency control of the same valve through means responsive to the temperature in the region of heat application.

A further object resides in providing service and safety control for devices of the character described with a minimum number of parts.

Still another object of my invention is to provide a combined service and safety valve mechanism which is extremely simple and economical to manufacture and very effective in operation.

How the foregoing, together with such other objects and advantages as may hereinafter appear or are incident to my invention are realized,

is illustrated in preferred form in the accompanying drawing, wherein- Figure 1 is a fragmentary elevational view illustrating my improved control mechanism with certain of the parts -appearing in section and with the casing cover of the mechanism removed;

Figure 2 is a plan section taken on the line 2-2 of Figure 1, and

Figure 3 is a vertical sectiontaken on the line 3 3 of Figure 1.

In Figure 1 the valve control mechanism is indicated as a whole by the reference letter A, and is shown applied to a water heater B, having a water tank or storage vessel 4 and a lower compartment 5 in whicha main burner 6, such 5 as a gas burner, is located. The supply of heating medium or gas to the burner is controlled by a control valve C having a gas inlet 7 and a gas outlet 8, 'gas being led from the outlet 8 to the burner 6 by means of al pipe 9. The valve member 10 of the control valve is provided with a valve stem 11 which extends into the casing 12 of the control mechanism A. A suitable seal against leakage at the valve stem is provided which, in this instance, is illustrated in the form of a diaphragm seal 13. The valve 10 is normally urged to its closed position by means of a spring 14 and is adapted to be moved to its open position upon actuation of the valve stem 11.

Ignition means for the burner is provided in the form of a pilot l5 which may be supported in any suitable manner at a point closely adjacent to the main burner 6. This pilot receives its gas directly from the main gas supply by means of a pipe 16 which, in this instance, is shown connected into the casing of the control valve C at the inlet side thereof.

The valve control mechanism A comprises in general a supporting casing 12 having a removable cover, a valve actuator or snap arm 17, a lever 18, which may be termed a compounding lever, a thermostatic device D for causing actuation of the lever 18, and a safety device E including a lever 19 adapted to be operated by a thermostatic device F.

The snap arm 17 is pivotally mounted on a support 20 carried by the casing l2, the pivot being provided by means of knife-edge portions 21 on the snap arm engaging in V-notches 22 in the support 20. This snap arm is resiliently connected to the lever 18 by means of a spring 23 connected at its upper end to the upper free end portion of the snap arm 17 and at its lower end to the lower free end portion of the lever 18. It is to be noted that the disposition of the lever 18 with respect to the snap arm 17, and the location of the points of connection of the spring 23 to these members, are such that the snap arm will assume the position shown in Figure l .when the lever l8'is moved to the `left by the thermostatic device D, and that it will snap to the position shown in dot and dash lines at 24 when the lever 18 is moved to the right by said thermostatic device. The spring connection also serves to hold the snap arm in proper pivotal relation with the support 20.

With the snap arm 17 in the full-line position the valve 10 is permitted to move to its closed poition but when it snaps over to the position indicated in dot and dash lines at 24 the lower portion 25 of the snap arm, through its engagement with the valve stem 1l, moves the valve to its open position and thus supplies gas to the burner 6. Actuation of the snap arm to the positions just described is accomplished through the medium of the thermostatic device D now to be described.

The thermostatic device D comprises a support 26 adapted to be secured in the wall of the water tank 4 and carrying a tube 27 extending into the tank. This tube isconstructed of material having a high coefficient of thermal expansion and has located therein a rod 28 constructed of material having a low coeicient of expansion. The tube 27 is secured to the support 26 at its end 29 and the rod 28 is secured to the tube at 30 as by means of screw threads. This rod extends outwardly through the support 26 and into the casing 12 of the control mechanism, and at its free or extending end 31 it engages the lever 18 at a point closely adjacent the pivot 32. It will thus be seen that any movement of the rod 28 due to expansion and contraction is greatly compounded because of the construction just described and of the length of the lever 18, so that ample movement is provided at the free end of the lever 18 to cause the desired snap action of the arm 17 with consequent snap opening and closing of the valve 10. Adjustment of the thermostatic device D may beprovided by turning the rod 28 to the left or right as by means of a nut 33.

The operation of the device as thus far described is as follows. When the water in the tank is cold, the tube 27 contracts, thus moving the rod 28 to the right, which, due to its contact with the lever 18 at 31, rocks the lever to the right. This moves the lower end of the spring 23 toward the right an amount such that the spring creates a pull on the upper end of the arm 17 in a direction to cause it to snap into the position shown in dot and dash lines. Such movement of the snap arm causes it to move the valve stem 11 to the left to open the valve 10 and supply gas to the burner 6 and, assuming that the pilot is lit, this causes ignition of the burner.

When the temperature of the water rises to a predetermined value, the tube 27 expands, and since the rod 28 is attached to the tube at its free end it moves in a direction away from the lever 18. However, the spring 23 is creating tension on the lever 18 in a direction tending to move it to the left, and therefore the lever follows the rod 28. When the lever moves in this direction a predetermined amount the arm 17 is snapped into its other position, namely, that shown in full lines, this being due to the shifting of the lower end of the spring to the left. Thus the lower end portion of the snap arm permits the valve 10 to snap into its closed position to cut oif the supply of gas to the burner. When the water drops to a predetermined low temperature the valve is opened in the manner above described, and so on. The above operation is what may be termed the service control of the heater.

Referring now to the thermostatic device F, it will be seen that it comprises a tube 34 secured at its end 35 in the casing 12, and a rod 36 located therein, the construction being similar to that of the tube 27 and rod 28 of the thermostatic device D. The rod 36 is secured at its end 37 in the tube 34wand its free end 38 is adapted to contact with the lever 19 of the safety device E. The lever 19 is pivoted` at 39 in the casing 12 and is spring pressed in a direction to contact with the rod 38. A projection 40 is provided at the lower end portion of the lever 19, the amount of projection of which is such that when the lever is in the position shown in the drawing the snap arm 17 is free to move from one of its snap positions to the other.

The device F is so positioned that its tube is subjected to heat from the pilot 15, and therefore when the pilot is lit the tubeexpands and moves the rod 38 in a direction away from the lever.

whereby the lever assumes its position of noninterference with the snap arm. However, when the pilot is extinguished the tube 34 cools and contracts, thus moving the rod 38 in its other direction, whereby the lever 19 is swung to the right on its pivot and the projection 40 thereof engages the arm 17 to move it to its full-line position and thereby hold or lock it in the position in which the valve 10 closes to cut oil the supply of gas to the burner 6.

It will thus be seen that in the event the pilot is extinguished when the thermostatic device D effects opening of the control valve, the safety device E actuates the control device in a manner t0 close the control valve and prevent the escape of gas at the burner. Similarly, if for any reason the thermostatic device F should cool oi to its predetermined low temperature when the service thermostatic device D is effecting operation of the control device to hold the valve closed, then the safety device E prevents opening of the valve by a change in condition at the thermostatic device D. In either case the control valve will remain closed until the pilot is again lit, which is the only operation necessary in order to again restore the heater to service operation.

It is to be observed that even through the snap arm may be locked by the safety device E in its position of maintaining the control valve closed,

the compounding lever 18 is still free to move throughits normal range due to its resilient connection rto the snap arm, thus avoiding any strains on the lever or associated thermostat after actuation of the safety device.

It will be seen from lthe foregoing that I have provided an improved control valve mechanism for water heaters and similar appliances in which both service control and safety control are afforded with but a single valve. This is advantageous for the reason that the valve, owing to its being a service valve, is being frequently operated, and therefore when it is called upon to act as a safety valve it will not stick as might very well be the case if a separate safety valve were employed adapted to be actuated only under emergency conditions. Thus by employing the service valve also as a safety valve, it is preconditioned, so to speak, to ensure effective operation as a safety valve under emergency conditions. The number of parts employed is relatively few and the arrangement of parts is such as to ensure at all times, positive and effective action.

I clainfu-I 1. In a water heater having a main burner, a valve controlling the flow of a heating medium to said burner, spring means normally tending to close said valve and pilot means for igniting the burner, a thermostatically controlled snap arm engageable with said valve to open it and adapted to control spring closing of said valve under predetermined water temperature conditions, and thermostatically controlled means engaging said snap arm to lock it in the position in which the valve is closed under predetermined temperature conditions at the pilot means.

2. In a water heater having a main burner, a valve controlling the flow of a heating medium to said burner, and pilot means for igniting the burner, a snap arm engageable with said valve toopen it and adapted to control closing of said valve, a thermostat subject to water temperatures for controlling said snap arm, and a thermostat subject to pilot temperatures for controlling said snap arm.

3. In a water heater having a main burner, a

valve controlling the flow oi' a heating medium to said burner, and pilot means for igniting the burner, a snap arm operable on said valve to eieot opening and closing thereof, thermostatically controlled means engaging said snap arm to efiect such opening and closing under predetermined Water temperature conditions, and thermostatically controlled means engaging said snap arm to effect closing of the valve under predetermined temperature conditions at the pilot means.

4. In a water heater having a main burner, a valve controlling the flow of a heating medium to said burner, and pilot means for igniting the burner, an arm operable on said valve to effect snap opening and closing thereof, means for pivoting said arm on a xed part, thermostatically controlled means resiliently connected to said arm to move it to positions eiecting such snap opening and closing of the valve under predetermined water temperature conditions, and there mostatically controlled means engaging said arm to hold it in its position of eiecting closing of the valve under predetermined temperature conditions at the pilot means.

5. In a water heater having a main burner, a valve controlling the oW of a heating medium to said burner, and pilot means for igniting the burner, an arm pivoted on a fixed part and movable in one direction to effect opening of Vthe valve and in an opposite direction to control closing of the valve, thermostatic means responsive to Water temperatures for moving said arm in said directions 'and thermostatic means responsive to temperatures at the pilot means for holding said arm in the position in which the valve is closed when the temperature at said pilot means drops to a predetermined low value.

6. In a Water heater having a main burner, a Valve controlling the flow of a heating medium to said burner and pilot means for igniting the burner, the combination of control means for the valve comprising a support, a valve operating arm, means for pivotally mounting said arm on said support, a compounding lever pivotally mounted on said support, spring means connecting the free end portion of said lever to said arm to impart snap action to the arm in directions to eiect opening and closing of the valve when the lever is moved in opposite directions, a thermostat responsive to water temperatures in the heater for so actuating said lever whereby the valve is opened and closed in accordance with changes in water temperature, and thermostatically operated means responsive to changes in temperature at the pilot means movable to a position, when said temperature is at a predetermined low value, to engage and hold said arm in its position in which the valve is closed.

7. In a Water heater having a main burner, a valve controlling the iiow of a heating medium to said burner and pilot means for igniting the burner, the combination of control means for the valve comprising a support, a valve operating arm, means for pivotally mounting said arm on said support, a compounding lever pivotally mounted on said support, spring means connecting the free end portion of said lever to said arm to impart snap action to the arm in directions to effect opening and closing of the valve when the lever is moved in opposite directions, a thermostat responsive to water temperatures in the heater for so actuating said lever whereby the valve is opened and closed in accordance with changes in Water temperature, and thermostatically operated means responsive to changes in temperature at the pilot means movable to a position, when said temperature is at a predetermined low value, to lock said arm in its position in which the valve is closed and movable to a position, when said temperature is at a predetermined higher value, to unlock said arm to permit its being moved to its other position by the rst mentioned thermostat.

8. In a water heater having a main burner, a valve controlling the iiow of a heating medium to said burner, and a pilot for igniting the burner, means for controlling said valve including a valve actuator pivotally mounted on a xed part, a pair of thermostats for operating said actuator, one being responsive to Water temperatures in the heater to eiect movement of the actuator to open the valve at predetermined 10W Water temperatures and to eiiect movement of the actuator to cause the valve to close at predetermined higher Water temperatures, and the other being responsive to pilot temperature to hold the actuator in its position of causing the valve to close when the pilot is extinguished.

9. In a Water heater having a burner and a valve controlling the now of a heating medium to said burner, means for operating said valve comprising a thermostatically controlled lever, a platelike valve actuating member having a knife edge intermediate of its ends, a fixed support having a notch receiving said knife edge to form a pivot for said member, said support being located so that one free end portion of said member is in engagement with said valve, and springi means connecting the free end of said lever to thI other free end portion of said member, said "spring means being tensioned to hold said valve actuating member in pivoted relation to the support and to snapsaid member into valve opening and closing positions as said lever is thermostatically operated. y

10. In a water heater having a main burner, a valve controlling the flow of a heating medium to said burner, spring means normally tending to close said valve, and pilot means for igniting the burner, a pivoted snap arm, a compound lever resiliently connected to said arm to rock it on its pivot, said arm being so positioned with respect to said valve to actuate the valve to open position when rocked in one direction and to control spring actuation of the valve to closed position when rocked in its other direction, thermostatic means for actuating the compound lever in accordance with water temperature conditions, and thermostatically controlled means engaging the snap arm to lock it in its position in which the valve is spring closed under predetermined temperature conditions at the pilot means.

ARCHIE HUGH STRONG.