US2794600A - Valve operator - Google Patents

Description

June 4, 1957 E. c. EHLKE VALVE OPERATOR Filed Dec. 1o, 1954 To CH Akcleo FEELER 5131,@

INVENTOR. EDWARD C, Enum?.

United States Patent O vALvE oruRA'ron Edward C. Ehlke, Milwaukee, Wis., assigner, by mesne assignments, to Controls Company of America, Schiller Park, lll., a corporation of Delaware Application December 10, 1954, Serial No. 474,449 1 Claim. (Cl. 236-48) This invention relates to a v-alve operating mechanism which has operating characteristics particularly adapting the device to the control of gas ow to a burner.

It is well known that a gas burner requires a greater iiow for ignition purposes than is required to sustain combustion 'after ignition has taken place. ln many cases it is desirable to provide a modulating ame at a burner within the limits of the combustion range. Controls aiording a modulating ow nate have heretofore been generally characterized by the fact that the low limit of the modulating range was necessarily the ow ratte occurring when the operating mechanism opened the valve for ignition purposes. Therefore, the low limit on the modulating range was higher than desirable when considering the modulating portion of the operation alone. The present control apparatus will provide a lower limit for the modulating portion of the operating cycle while providing |a high initial ow rate for ignition purposes. Thus, the present unit provides a high iiow rate for ignition purposes with a far greater modulating range than found in the prior art devices.

The principal object of this invention is to provide a valve operating mechanism capable of modulating the valve over `a wide range while opening the valve for ignition to a high flow position well above the low ow rate encountered in the modulating portion of the operating cycle.

Another object of the present invention is to provide a control of the type described which may be produced at low cost. A

Other objects Iand advantages willbe pointed out in, or be apparent from, the specification and claim, as will obvious modications of the single embodiment shown in |the drawing in which the single figure represents a vertical section through a control unit incorporating the present invention.

The device illustrated in the drawing is adapted to be used in connection with other apparatus such Ias Athe basic unit shown in application Serial No. 475,174 of Heiser et al., now Patent Number 2,743,871. However, the present device could yalso be used las a separate control by adapting the inlet and outlet ports for pipe fittings or the like. The control is encased in a split housing 16 having `a bottom portion 12 and an upper housing 14. The bottom housing is provided with inlet 16 and iiow through outlet 18 is regulated by the series valves 29 and 22; although, as will be pointed out more fully hereinafter, the flow can be regulated by Ia single valve if desired. Inner or small valve is provided with a short stem 24 having a shoulder or washer 26 limiting the downward movement of the valve with respect to outer or annular valve 22 under inuence of light spring 28 by contact with annulus 30 mounted in the outer valve structure. Thus, the light spring 28 urges small valve 20 downwardly to the limit position determined by contact of washer 26 with annulus 30. As shown in the drawing, light spring 28 has been deflected by reason of seating both the small valve land annular valve 22, It

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will be appreciated that as the large valve moves up-Y wardly, the small valve would remain seated until the lost motion is taken up between the two valve structures whereupon the small valve would be unseated also. The stem of annular vtalve 22 projects through a cooperating hole in lever 32 and is connected to the lever by coil spring 34 compressed between the lever band washer 36.

The small valve 20 is designed to control the main flow to the outlet 18 and when valve 20 is seated, the major portion of the flow to the outlet is cut oir. However, until lthe `annular valve 22 seats `a small ow rate can occur by passage between the annular valve 22 and its seat 38 into the annular well 40 and through the small by-pass conduit 42. The low limit of the modulating portion of the operating cyole of this valve mechanism is determined by the seating of valve 20 on its seat 44 while flow continues through the ny-pass 42. The o position is, of course, determined by seating both valves.

Lever 32 which carries both valves is pivotally on pin 46 mounted in Ihousing 10. The lever is provided with a cut-out 48 through which the right-hand end Si) of lever 52 may project to overlie lever 32. Lever 52 is also pivotally mounted on pin 46 and is urged upwardly by compressed spring 54. Lever 32 is yieldably con-` nected to lever 52 by means of spring 56 compressed between the underside of lever 32 and the head of depending adjustable screw 58 threaded into the right end 50 of lever 52. Thus, when the lever 52 tends to move upwardly, the spring 56 would be compressed if the valve lever 32 were restrained from upward movement. The force of spring 56 can be adjusted by adjusting screw 58 and will increase as the degree ofl compression of the spring is increased as encountered when the levers 52, 32 tend to move Iapart under the conditions just described.

Lever 52 constitutes the control lever in that it receives the conltrol motion from the temperature responsive mechanism. This mechanism is mounted on the upper housing 14 in the tubular portion 60. The temperature responsive mechanism includes a charged bellows assembly including the cylindrical outer cas-ing 62 containing the bellows 64. The casing 62 is adapted for vertical movement within the tubular chamber 69 las will be pointed out more fully hereinafter. Bellows chamber 66 is connected by capillary tube 68 to a charged temperature responsive bulb, not shown. As the temperature at the bulb varies, the pressure within chamber 66 will vary to eX bellows 64. This movement is transmitted to control lever 52 by means of pin 70. The headed upper end of the pin normally seats against shoulder 72 in fitting 74 by reason of the compression of spring 76 between the underside of tting 74 rand Washer 78 mounted on the pin. This spring is employed solely to allow overtravel in the event the system is subjected to an abnormally high temperature calling for greater bellows movement than can be had whereupon the spring 76 will collapse to permit the relative movement between the bellows Iand the pin :and prevent damage to the bellows. The top of fitting 74 is sealed by cap 75 soldered to the iitting. It is to be noted that the pin is brought into the inside of housing l0 through the seal Si) to prevent leakage of gas at this point.

The capillary tube 68 connects to chamber 66 through the iitting S2 projecting laterally from casing 62 through a slot 84 in the side of the tubular well 61B. The bellows `assembly is held in position by means of cap or knob-86 threadably mounted on the upper end of the tubular chamber 69 for rotation through approximately 360 degrecs determined by engagement of lug 88 with either side of the stop pin 90 mounted on housing 1t?. Rotation of the knob 86 is employed to determine the operating characteristics or the maintained temperature of the control. Thus, as the knob is turned from the position shown, the spring 54 acting on the underside of control lever 52 will move the enti-re bellows `assembly .upwardly to follow the position of vthe .knob S6. This will, of,

the bias of spring 54. This would normally tend totop'enV the valves. However, the valve lever 32 yis urged .towards the valve closed position bymeans of spring 94 compressed between seat 96 carried on the adjustable point 98 and seat lili?. carried on pin 102 projecting from lug 149,4 projecting from valve lever 32. Therefore, the spn'ng94 exerts a force component generally parallel to the tofA the valves and thus tending to seat the valves. This force can be adjusted by adjusting member'98 tand-the force .of the spring is adjusted to be greater Vthan the force of spring 56 when the parts are in the position shown. Therefore, when the control lever 52 moves upwardly, the valve lever 32 will not yfollow and this results in compressing spring 56 until the increased Vforce of spring V56 is greater than the vertical lcomponent of spring 94. When this occurs, the spring 56 will act to swing 'lever 32 upwardly and open both valves to the substantially `fully open position. The reason -that the valves go to the substantially full open position is that upon the lever 32 starting its upward movement the vertical force component of spring 94 steadily decreases and the system acts with a snap action up to the point at which the valve lever contacts the underside of the control lever. As the pressure within the chamber 66 varies now with temperature changes, the two levers will act in unison to achieve a modulating action between the upper and lower ranges of flow.' The low range of flow is determined when the small valve 2Q seats. At this point, the force of spring 94 is substantially equal to the force of spring 56 andany further downward movement of the control 'lever will necessarily result in swingingk pivot point 102 of spring 94 downwardly to result in Ia greater vertical force component exerted by spring 94. This will snap the valve 22 shut since the .initial movement of lever'32 from this point onWardly results .in further increase of the vertical force component of spring 94. Therefore, the valve will open and shut'with asnap action with the opening movement being substantially to the full open position and the closing movement occurring 'from a very low flow rate position.

While the present structure is shown -as employing two series valves, the device can be made to operate with only one valve controlling flow through a single port. This will be appreciated since the forces exerted by springs 94 and 56 can be balanced so the single valve would be at its lowest ilow position just prior to spring 94 overbalancing spring 56. The present structure permits of slightly greater accuracy in regulating flow land is for that reason preferred.

It will be appreciated that other variations of the present structure can be employed. For instance, the biasing forces need not be springs, but can be any other devices which will vary the exerted force upon changes inV spatial relationships of parts. One such device which would be readily suggested would be a magnet which,of course, increases its pull as the pole faces approach. For this reason, the present structure is to be taken as being exemplary only, but not as being a limitation upon the scope of the claim. It will also be appreciated that other temperature responsive devices might be employed in lieu of the bellows system illustrated. The bellows system is preferable in that it is Well ,suited to a modulating action.L

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art .that various changes and modiiications may be made therein without departing from Ythe spirit of the vinvention or from the scope of ,the appended claim.

I claim:

A valve operator comprising, a housing having an inlet and an outlet, a pivot `in said housing, a valve lever mounted on said pivot, a valve carried'by the lever and adapted to cooperate with theY outlet in regulating ilow from the casing, temperature responsive means including an element movable in response to temperature variations, aV control lever mounted on said pivot and ,operatively connected to said element so thelever follows movement ofthe element, a spring connecting the levers to normally cause 'the levers to move inunisonbut allowing the valve lever to move toward or remain at the valve closed Vposition independently of thecontrol lever action,V saidrspring exerting an increasing force on the valve 'lever urging the valve lever towards the control lever as the levers moverapart, means for adjusting the force exerted by the spring, a second spring ycompressed lbetween the valve lever and the housing 'to exert an increasing vforce component on Vthe lever in the Vvalve seating direction as the lever moves the valve .towards the seat, and means for adjusting `the force exerted by said second spring.

References Cited n the tile of this patent UNITED STATES PATENTS ,1,340,513 Youngman .M'ay 18, 1920 2,249,623 Taylor `Iuly l5, `1941 2,267,688 Landon Dec. 23, A1941V 2,387,792 Holmes Oct. 30, 1945

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