US3477641A

US3477641A - Flow interrupter type gas safety control operated by rotary knob for pilot,on and off in any rotary position of knob

Info

Publication number: US3477641A
Authority: US
Inventors: Richard K Fairley; Lourdes V Mccarty
Original assignee: Controls Company of America
Current assignee: Eaton Corp
Priority date: 1967-06-23
Filing date: 1967-06-23
Publication date: 1969-11-11
Anticipated expiration: 1986-11-11
Also published as: DE1751431A1; FR1573352A; GB1201106A; JPS5016539B1; NL6808838A

Description

NOV. 11, 1969 R, K FMRLEY ET AL 3,477,641

FLOW INTERRUPTER TYPE GAS SAFETY CONTROL OPERATED BY ROTARY KNOB FOR PILOT, ON AND OFF IN ANY ROTARY POSITION OF KNOB Filed June 23, 1967 oFF 52 E- 74 76 @Si 72 Q2 M 66 B n ze 7- I/azJl l ,l Il Il 00 Je ,GO f@ @W96 1V l@ 5246 'l l K 44 e4 8o 40 42 1 1 f 43 32 l f/g 20* /7 20 Ix k f a 3 7 'l J7 j A Q/fzwwzw' United States Patent O 3,477,641 FLOW INTERRUPTER TYPE GAS SAFETY CON- TROL OPERATED BY ROTARY KNOB FOR PILOT, ON AND OFF IN ANY ROTARY POSI- TION OF KNOB Richard K. Fairley, Deerfield, Ill., and Lourdes V. McCarty, Milwaukee, Wis., assignors to Controls Company of America, Melrose Park, Ill., a corporation of Delaware Filed June 23, 1967, Ser. No. 648,490 Int. Cl. F23n 5/06; G05d 23/12 U.S. Cl. 236-1 10 Claims ABSTRACT OF DISCLOSURE The manually operated knob is rotated to turn cam surface to set the bias on and temperature to be maiutained by the temperature responsive valves. In any rotary position of the knob it can be pushed in (pilot position) to interrupt gas ow to the main burner while allowing flow to the pilot burner for ignition purposes and the knob may be pulled out to allow the safety valve to close even though the thermo-electrically energized electromagnet is energized. The knob cannot be depressed to pilot if the magnet is still energized after having moved the knob to olf On, off, and pilot functions are obtained without changing temperature setting.

CROSS-REFERENCES TO RELATED APPLICATIONS The means preventing movement to pilot after off actuation until the thermomagnet is de-energized is claimed in application Ser. No. 648,489.

The snap andmodulating valve arrangement is claimed in application Ser. No. 647,766.

BACKGROUND OF INVENTION The flow interrupter type safety control is well known in the art but has generally required some separate means to turn off the gas. There have, however, been some designs which can turn off the gas. For example, Thomas United States Patent No. 2,988,098 shows an arrangement for rotating the knob to uncouple the safety valve from the electromagnet and allow the valve to close. This patent also shows an arrangement requiring recoupling before the safety valve can be reopened and the recoupling is possible only after the electromagnet is de-energized. This latter feature satisfies some of the newer safety requirements.

SUMMARY OF INVENTION The present invention combines the aforesaid features of a ow interrupter operable to pilot-on-ofr' with a rotary knob which also sets Ithe temperature to be maintained by the control and the rotary position (temperature Setting) of the knob need not be disturbed to obtain the pilot-on-of operation. Hence a single knob controls all functions.

DESCRIPTION OF DRAWING The single figure in the drawing shows a vertical section through the control with some of the parts simplilied or rendered schematically for the sake of clarity.

DESCRIPTION OF PREFERRED EMBODIMENT `The control 'housing 10 is provided with an inlet 12 leading to chamber 14 through the cylindrical filter 16. The safety valve 17 comprises a slightly dished resilient seating member 18 backed up by plate 20 which is slidable on stem 22 between the limits defined by the two 3,477,641 Patented Nov. 11, 1969 ice wire snap rings 24, 26. The upper hub portion of plate 20 has a threaded section receiving the cap 28. The very light spring 30 urges the safety valve upwardly to the limit imposed by the upper ring 24. A release plate 32 is fixed on the stem with its outer rim turned downwardly and is urged upwardly by the compressed spring 34. The lower end of the shaft 22 carries the usual armature inside the housing 36. Also contained in the housing is an electromagnet which is connected to a thermocouple 37 heated by llame at pilot burner 39 to generate suflicient energy to energize the electromagnet sufficiently to hold the armature to the magnet but insuiciently to attract the armature. This isa rather customary use of electromagnetic safety controls. If the electromagnet becomes de-energized because the pilot flame goes out then spring 34 will move release plate 32 and stem 22 upwardly `to close the safety valve on seat 38.

Immediately downstream of the safety valve there is a conduit 40 leading to the pilot burner 39. Immediately downstream of this conduit there is a seat 42 against which the ow interrupter valve 44 may seat. This valve is urged downwardly by spring 46 to rest on the outwardly turned flange 48 of sleeve 50 connected to plunger or shaft 52 and containing spring 54 which acts against the head of pin 56 to urge the pin downwardly with a force greater than spring 30 but less than spring 34. In the position shown the thermocouple has been energized sufficiently to hold the safety valve open and there is flow to the pilot burner through outlet 40 and the interrupter valve is held open by reason of its engagement with the shoulder 48 on sleeve 50 which is unable to move downwardly. In this position it will be noted that spring 54 is slightly compressed. If the electromagnet becomes deenergized spring 34 has sufficient force to overcome spring S4 acting on pin 56 to move the safety valve upwardly and close the safety valve to thereby interrupt all ow of gas both to the pilot 39 and the main burner 57.

1f, starting from the normal on position shown in the drawing, the knob 55 is retracted, shaft 52 will be pulled outwardly which necessitates the movement of the spring loaded detent ball 58 until it is free to drop on the other side of the spindle portion 60 of the plunger. Th-us it would then be seated on the underside of the spindle. At this point the pin 56 has taken up the lost motion between the head of the pin and the inside surface of the sleeve member 50i and has been withdrawn, whereupon the light spring 30 acting on the underside of the safety valve can move the safety valve 17 upwardly at least far enough for the flexible valve portion 18 to seat against seat 38 and interrupt ow. This having occurred, the thermocouple will cool sufliciently to release the armature and allow spring 34 to move the release plate 32 upwardly and continue the closing action on the safety valve. If, however, rather than waiting for the thermocouple to cool down, the user immediately tried to reset the control by pushing down on knob 55 past the position shown so as to rst seat the interrupter valve 44, the action would be ineffective to accomplish the normal resetting action since the inwardly

biased latches

62, 62 would have moved in underneath the plate 20 of the safety valve and would prevent any opening of the safety valve. It will be appreciated that

latches

62, 62 are selfbiased inwardly and if plate 32 is down (retained) and plate 20 is up (seating valve 18) the latches can move between plates 32 and 20 until plate 32 is released to spread the latches. Therefore, the user would of necessity have to wait until the thermocouple became cool to de-energize the electromagnet and allow the release plate 32 to move upwardly and spread the

latches

62, 62 to the position in which they can no longer block downward movement of the safety valve. This, then, prevents the 3 user from undertaking to light the burner under conditions which could allow full ow of raw gas to an unlighted burner.

Under normal operating conditions the resetting action occurs by depressing the knob 55 which will again move the detent 5S out of the way and the interrupter valve 44 is seated rst and during this period of time the spring 54 is compressed until it virtually goes solid, that is, acts as a solid member. Continued downward motion of the knob and its plunger 52 will now act to move the safety valve off its seat and move the armature to the electromagnet. This now allows flow only to the pilot burner 39 since flow past the interrupter valve is prevented. After ignition has been effected release of the knob allows spring 64 to return the knob to the normal position shown and the parts will have been restored to the normal operating condition shown.

The present control is unique in that the knob 55 can be rotated to adjust the temperature. Thus it will be noted that keyed to the shaft 52 there is a collar 66 having a cam track 68 formed therein and the left end 70 of lever 72 contacts and is positioned by the cam track. The lever 72 pivots about pin 74 and the right end is connected by means of adjusting screw 76 to actuating pin 78. The lower end of the actuating pin acts on a combined snap and modulating valve arrangement. For the purpose of understanding the present invention it is only necessary to know that as the pin 78 moves down the rst action which occurs is to open snap valve 80 and thereafter continued motion will operate to open the modulating valve 82. When the snap valve 80 is opened flow passes through the pressure regulator, designated by the box 84, and thence through the now open snap valve to conduit 86 which leads to the main outlet 88. The amount of gas which can flow through the bypass conduit 86 is adequate for the low re condition. Then as the pin moves down more the valve 82 can open to add additional fuel to that supply until the maximum flow rate is reached. The pin 78 and lever 72 are actuated by bellows 90 acting on lever 92 which is pivoted on pin 94 and urged by spring 96 to follow the motion of the bellows pin 100. The lever 92 carries the pivot pin 74 and the spring 102 compressed between the two levers causes lever 72, to follow the motion of pin 74 as modified by the position of cam 68 acting on the end 70` of lever 72. It will be understood that the bellows is connected by capillary tubing 104 to a suitable bulb 106 placed in the heated medium so that the pressure within the bulb and bellows assembly varies in accordance with temperature.

From the foregoing it will be appreciated that the present control provides a single knob 55 which can be used to actuate a ow interrupter assembly both to the normal operation of resetting and the on position but can also cause the safety valve to close even though the pilot is still energizing the electromagnet. Furthermore, all of these functions can occur in any rotary position of the knob. The knob can set the temperature control and the setting need not be altered during operation of the knob to reset or oi What is claimed is:

1. A gas control including a housing having an inlet, a pilot outlet and a main outlet,

resettable safety valve means requiring a linear resetting action and operative when reset to respond to a control condition to allow flow to both outlets and to prevent such flow when in its off position,

reset means for imparting the linear reset action to the resettable means and including interrupter valve means for preventing ilow to the main outlet during resetting,

a manually operable knob having a normal axial position and mounted for axial movement and connected to the reset means for operating the reset means upon being depressed,

said knob also being rotatable about its axis,

control means including temperature responsive valve means the response temperature of which is affected by the rotary position of the knob,

'a spring biasing the knob to its normal axial position,

`said knob being mounted for withdrawal from its noranal position and operative upon such withdrawal to effect movement of the resettable safety valve means to the off position.

2. A gas control including a housing having an inlet,

a pilot outlet anda main outlet,

a safety valve operative when closed to prevent flow to both outlets and when open to allow such flow,

an armature,

an electromagnet energized in response to a control condition to retain the armature in attracted position,

said safety valve being connected to the armature and held open when the armature is in attracted position,

reset means for moving the armature to attracted position and opening the valve,

said reset means including an interruptor valve preventing ow to the main outlet during resetting,

said pilot outlet being supplied from the space between said valves,

a manually operable knob mounted on the housing for rotary and axial movement and connected to the reset means for actuating the reset means upon axial movement of the knob from its normal position to ya reset position,

and a thermostat adjusted by rotary movement of the knob,

said knob being axially movable in any of its rotary positions to eifect resetting without affecting the adjustment of the thermostat.

3. A control according to claim 2 in which the safety valve is connected for limited motion relative to the armature with la spring acting therebetween tending to close the safety valve notwithstanding the attraction of the armature to the electromagnet,

said reset means including means for yieldably holding the safety valve to the armature with a force greater than the force of the spring acting between the safety valve and the armature,

said knob being movable from its normal axial position in a direction opposite the reset position to an off position in which the yieldable holding means is ineffective and the safety valve can close.

4. A gas control of the type having a housing lprovided with an inlet, a main outlet and a pilot outlet with a safety valve controlling flow to both outlets and held open by an electromagnet which requires resetting following de-energization of the electromagnet, and resetting means including a plunger which is depressed from its normal position to reset the safety valve while an interrupter valve carried by the plunger blocks flow to the main outlet, the improvement comprising,

thermostatic control means,

adjusting means carried by the plunger yand operative upon rotation of the plunger to adjust the thermostatic control means,

means responsive to withdrawal of the plunger from its normal position to close the safety valve regardless of the state of energiz'ation of the electromagnet,

said plunger being actuatable to reset or close the safety valve in any rotary position so the adjustment of the thermostatic means is unaifected.

5. A -gas control according to claim 4 in which the electromagnet armature is connected to the safety valve with a limited motion connection and a spring biases the safety valve to closed position even when the armature is held by the electromagnet,

said plunger including a pin acting on the safety valve when the plunger is in its normtal or reset position and withdrawn from the safety valve when the plunger is withdrawn from its normal position,

a spring biasing the pin from the plunger with a force `greater than the spring biasing the safety valve closed,

said yarmature being biased to the valve closed by a spring exerting a force greater than the force of the spring biasing the pin from the plunger.

6. A control according to claim 5 including a detent acting on the plunger t0 hold it in either its normal or its withdrawn position,

and a spring acting on the plunger to move it from the reset position to the normal position upon removal of the actuating force applied to the plunger during resetting.

7. A control according to claim 6 including valve means downstream of the nterrupter valve for controlling flow to the main outlet,

said thermostatic means includin-g a motor device responsive to the temperature of the heated medium and lever means connected to the motor device and the valve means.

8. A control according to claim 7 in which the adjusting means comprises a cam carried by the plunger for rotation therewith but allowing 'axial movement of the plunger without movement of the cam, said cam acting on the lever means.

9. A gas control of the type having a housing provided with an inlet, a main outlet and a pilot outlet with a safety valve controlling flow to both outlets land held open by an electromagnet which requires resetting following de-energization of the electromagnet, and resetting means in cluding a plunger which is moved axially from its normal position to a reset position to reset the safety valve while an interrupter valve carried by the plunger blocks flow to the main outlet, the improvement comprising,

mounting the plunger for axial movement to an 01T position,

means responsive to movement of the plunger to the oi position to close the safety `valve regardless of the state of energiz-ation of the electromagnet.

10. A gas control according to claim 9 in which the plunger is rotatably mounted and the plunger is axially movable to elect its functions in any rotary position of the plunger.

References Cited UNITED STATES PATENTS 3,129,884 4/1964 Baatrup.

2,557,927 6/ 1951 Abrams et al.

2,628,677 2/ 1953 Strobel.

2,690,873 10/ 1954 Vaughn 236-21 2,7017,5 17 5/ 1955 Strobel.

2,911,152 11/1959 Weber et a1.

EDWARD I. MICHAEL, Primary Examiner U.S. Cl. XR. 137-66; 431-75