US2694408A

US2694408A - Valve control mechanism

Info

Publication number: US2694408A
Application number: US304707A
Authority: US
Inventors: Fred W Mcrae
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-08-16
Filing date: 1952-08-16
Publication date: 1954-11-16
Anticipated expiration: 1971-11-16

Description

Nov. 16, 1954 F. w. MCRAE VALVE CONTROL MECHANISM Filed Aug. 16, 1952 F950 U. M: 1645 INVEN TOR.

United States Patent 9 2 Claims: (G1. 137-460.);

This invention relates to: improvements in'valvecom trol mechanisms.

An object of. the inventionsisto provide a construction wherein there. is a. normally-- open valve closure urged into closed. position either'bygravityor otherwise,v

and which is.releasablyheldiin open positionand controlled by a mechanism responsive to the'rate of flow through the valve;

Valves of this type have a large variety'of: different For example, the combination embodying the present invention may be incorporated" ina pipe liner Theleading from a large ammonia storage tank. pressure at which the ammonia is maintained in the storage tank may vary widely; If such a line in which thepresent valve is incorporated leads-from:the storagetank to a compressor, the compressor will draw ammonia from the storage tank at a predetermined rate with very little variation. Inthe event'that the pipe line leading from the storage.tank.to-the.compressorshould break, the rate of flow through the valve would'materially increaseand it would be desirableto: immediately-close.

the'valve so that.all.of.the.arnmonia in'the storage tank would not be permittedtoescape, It will be appreciated that under such. circumstances. where: the pressure in the storage.:tank..may. vary considerably that the control mechanism that efiects.a.closing.-:of;'the:valve should be largely independent of..pressure..variations. but should 'be immediately responsive. to. material variations in= the rate of flow through. the valve.v

An object of the present invention is to provide a valve control mechanism that satisfactorily meets all of these requirements.

Another object of the invention is to provide a valve control mechanism having the above-mentioned characteristics wherein the valve can be closed if desired manually or from remotely located control points.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a longitudinal vertical section through a construction embodying the present invention; and

Fig. 2 is a vertical section taken substantially upon the line 2-2 upon Fig. 1.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved construction comprises a valve body or housing having an inlet 11 and an outlet 12. The inlet and outlet are preferably flanged to cooperate with companion flanges on the pipe line or conduit Within which the body is adapted to be inserted. Within the body there is disposed a valve seat 13 engageable by a closure 14 that is loosely mounted on a swingable arm 15. This swingable arm is mounted on a transversely ex tending pintle 16, a portion of which preferably extends through the wall of the housing 10 to the exterior thereof so that it may be rotated from the exterior of the housing to swing the closure into open position. The closure 14 is normally held in open position by means of a latch 17 pivotally mounted on a pin 18 that is supported on ears 19 within the housing. This pivoted latch has a dog 20 engageable with a finger 21 on the arm to releasably hold the closure in open position. The latch In this manner; if the rate of flowthrough the valve varies materiallyfrom apredetermined' orset rate. the valve. will be caused toautomatically ICC Z 1.74; has:- at; weight: 225 that .urgesithe. latch. to swing in: a. counterclockwise direction-as.viewecbiniFig.. l', to releasethe-i.closure.=. The..closure:.1i4; is. adapted" to swing by gravity orpitzmay befurgedbyi a2 springzinto'. closing 'posi tion against :the;seatr 13;

Thee abovedscribed construction is not. new "in the art and; ittwill? be? appreciatedtlthatother types of self closing valves may be'isubstituted itherefor'if 3 desired:

In association. with: the: valve: there is: :an'a orifice .plate: 23 having: an. orificet24i 'therein. Thisaorifice plate-is illustrated as being replaceably clamped between. the.- downstream end of. the body" 101 and the t adjacentr companion: flange: on the-conduit. The: orifice plate :may' be: removed and. replaced with. other: plates= having-larger: or smaller: orifices ttherein tormeettvarious conditionss Upstream with. respect". to the? orifice plate: there isa. tubing. 25: connected as: at 261 to. thevinterior 'of the housing 10: and serving: to'conduct pressureto a dia phragm' housing. generally" indicatedi at. 27. Down-- stream:.with' respectitoa the orifice plate 23 there" is a similar tubing '28 connectedftot the interior ofthecon'-- duitand serving. to conductrpressure: to: the: diaphragm housing v271 This tubings'may have aalthree way 'solenoid valve 29 incorporated therein" for:' a purpose; h'ereinafter tozbe. described.

The.. diaphragm: housing: 27 is divided into two' compartments-or: chambers? 3lliand; 31 by a.=diaphragm 32. The tubing 28 leads-:to"the-:chambersSOf andithe'tubing 25: leads to: the chamberr31i A compression spring 33 urges"the?diaphragm"325downwardly; 'and the pressure "exerted by-this springnion the .diaphragm' mayrbeadjusted.- by means of a threaded plug 34. 35 indicates merely a. closure: plug" for the top." of. the. diaphragm housing which may be:removedtfor"thespurposeflof adjusting the: plug-13A- andiconsequentljc the pressure: exerted by the springi33ionithesdiaphragmz.

Abovex.the-=latch r 17 "theretissav slida-ble pin 36 that en'- gages the-lop: of tliedatchz with. pin: is equipped" with? a-zhead 38 and: is.= surrounded by meansaofi'a compression". spring139! .hich urges the pin upwardly. The heart 38*; engages. a-pim 40 that slida-bly extends 7 through an gland. 41" with" aw relatively closer fit: The.-upper'end of thisapim is;engageab le: -with1a stud. 42 our the; under rside: of the diaphragm.

In; the normah position the closure 14'iiselatched i in" its 4 opencpositiomby thelatch lflr. Variationsin pressure in: the ammonia tank or in the fluid supplied to the valve have no noticeable effect on the valve. Thus, a high increase in pressure is conducted through both the

tubes

25 and 28 to opposite sides of the diaphragm 32 and are balanced or substantially so. Conversely, a decrease of pressure is effective through the

tubes

25 and 28 on opposite sides of the diaphragm without aifecting it. Under normal conditions a compressor downstream with respect to the orifice plate 23 will draw ammonia from the supply tank through the valve at a predetermined rate. As long as this rate persists there will be a slight dif ferential in pressure created by the orifice plate. Thus, the pressure transmitted to the diaphragm housing through the tube 25 will be slightly greater than the pressure transmitted through the tube 28. This slightly higher pressure in the chamber 31 than the pressure that exists in the chamber 30 would urge the diaphragm 32 upwardly. Such upward movement, however, is opposed by the compression spring 33. Consequently, under normal conditions, while the compressor is drawing fluid at a predetermined rate there is no tripping or actuation of the valve.

On the other hand, if the pipe line downstream from the orifice plate between the orifice plate and the compressor should break this would permit flow through the valve to occur at a very materially increased rate. The difierential in pressures in the

tubes

25 and 28 would consequently increase so that the pressure in the chamber 31 would be sufiiciently higher than the pressure in the chamber 30 to cause the diaphragm to lift against the pressure of the spring 33. When the diaphragm is lifted it permits the pin 36 to be elevated by its spring 39, thus permitting the weight 22 to rotate the latch 17, allowing the closure 14 to immediately close and seat against the seat 13. In this way, in the event that the pipe line leadmthe housing 10. This 1 ing to the compressor should break or become damaged the valve will be caused to automatically close to prevent further escape or loss.

The valve may be manually or intentionally tripped by means of the solenoid valve 29. The electric conductors leading to the solenoid of this valve may be connected to any electric switch located in the immediate neighborhood or at a remote control point. When this solenoid valve is energized by closing the electric circuit through its solenoid its effect is to shut off the tube 28 and open the chamber 30 to atmosphere. Any ammonia that may be in the chamber 30 and in that portion of the tube 28 that is between the solenoid valve 29 and the diaphragm housing 27 is lost to atmosphere but its volume is negligible.

From the above-described construction it will be appreciated that an improved valve control mechanism is provided which is not influenced by variations in pressure in the fluid conducted therethrough but which is infiuenced by variations in the rate of fiow therethrough. Consequently, any increase or decrease in the pressure of the fluid supplied to the valve does not cause it to trip. But in the event that some circumstance causes the rate of flow through the valve to materially change the valve will be automatically tripped and caused to close.

The tubings and 28 may have manually operable valves inserted therein if desired so as to isolate the diaphragm housing from the line during the period that the pipe line is being filled. When the line has been filled and conditions have been more or less stabilized in accordance with normal operations, such manual valves, not shown, may be opened and left open.

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A valve operable to shut off when flow therethrough exceeds a predetermined rate comprising a valve body having an inlet and an outlet and a valve seattherebetween facing toward the inlet, a valve closure swingably mounted in the body adapted to seat upon said seat, a latch pivotally mounted in said body engageable with the closure to releasably hold the closure in open position, said latch being biased to release the closure, a diaphragm and housing therefor on the exterior of the body, means operatively connecting the diaphragm and the latch through a wall of the body whereby the diaphragm may hold the latch in opposition to the bias thereon in engagement with the closure, means for creating a pressure differential in the flow of fluid that passes through the body, and means for conducting the differential pressures to opposite sides of the diaphragm in such a manner that as long as the pressure differential does not exceed a predetermined degree the diaphragm will hold the latch in engagement with the closure but when the differential exceeds a predetermined degree the diaphragm will allow the latch to release the closure and thus allow the closure to close.

2. A valve operable to shut off when flow therethrough exceeds a predetermined rate comprising a valve body having an inlet and an outlet and a valve seat therebetween facing toward the inlet, a valve closure swingably mounted in the body adapted to seat upon said seat, a latch pivotally mounted in said body engageable with the closure to releasably hold the closure in open position, said latch being biased to release the closure, a diaphragm and housing therefor on the exterior of the body, means operatively connecting the diaphragm and the latch through a wall of the body whereby the diaphragm may hold the latch in opposition to the bias thereon in engagement with the closure, said means including a spring exerting pressure on the diaphragm in a direction to cause said means to allow the latch to release the closure, a spring in the diaphragm housing arranged to exert pressure on the diaphragm in opposition to the mentioned spring, means for adjusting the pressure exerted by the last-mentioned spring, means for creating a pressure differential in the flow of fluid that passes through the body, and means for conducting the differential pressures to opposite sides of the diaphragm in such a manner that as long as the pressure differential does not exceed a predetermined degree the diaphragm will hold the latch in engagement with the closure but when the differential exceeds a predetermined degree the diaphragm will allow the latcli to release the closure and thus allow the closure to c ose.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 665,181 Confer Ian. 1, 1901 1,478,320 Baxter Dec. 18, 1923 1,787,686 Kerr Jan. 6, 1931 2,182,873 King Dec. 12, 1939 2,327,055 McMahon Aug. 17, 1943 2,357,133 Rider Aug. 29, -1944 2,587,358 McRae Feb. 26, 1952 2,613,683 Baird Oct. 14, 1952