US2697999A - Low-pressure warning device - Google Patents

Description

1954 R. R. CROOKSTON ETAL 2,697,999

LOW-PRESSURE WARNING DEVICE Filed April 22, 1953 2 sheets-sheet} I i 29 F! G. I. 22 I !6- INV ENTOR.

Rqberf R. Crooksfon, By Irving Maser,

ATTOR E Dec. 28, 1954 R. R. CROOKSTON ETAL LOW-PRESSURE WARNING DEVICE Filed April 22, 1953 ii. l

2 Sheets-Sheet 2 F I G. 3.

11 72 Ill 62 mmvrm Robert R. Crooksfan, BY Irving Maser,

ATTO N United States Patent LOW-PRESSURE" WARNING' DEVICE Robert R..Crookston.and Irving Moser, Houston, Tex.,

assignors, by mesne assigmnenta tot Standard Oil D'evelopment Company,uElizabeth, N. J., a corporation of Delaware Application April 22, 1953, ,SerialN=..350,496

3 Claims. (Cl...11634) I The-present invention isdirected'ato' a low pressure warning device. rected to a device which-is operative. when pressure falls below a predetermined figure. In its more specific aspects, the invention is directed to a low air-pressure warning device-which emits an audible .signal.

Moreparticularly, the invention is di- The present invention may. be br iefly describ ed as a L Asecond-lateral passageway arranged in the chamber and is connected. to themovable valve actuating member and with the housing. Spaced apart from the firstdiaphragm inthe chamber is a second diaphragm whichis-provided with-ports communicating fluidly the first and second passageways. A

valve is arranged in the housing which-base valvestem 1 normally in inoperative relationship with the valve actuating member. A biasing means, such ,as-ahelical coil spring, embraces the valve actuating member and normally urges the valve actuatingmember toward and holds the valve actuating member intoengagement with the valve stem. The housing has an audible warning means connected thereto and to thechamber which allows the warning means--to be actuated by the biasing means overcoming a pressure exerted in a space between the diaphragms.

The valve may be arranged above: the-first-diaphragm and within the central'bore suchthat onthe-valve actuating member pressing against the valve stem air is allowed to pass intothe audible' means andcausesa signal to be emitted. Preferably,- however, the valve is arranged in the inlet in relationship with thevalveactuating member such that on the biasing means overcoming the diaphragms thevalve stem is urged downwa-rdly allowing air to pass from-the inlet through, the central bore to theaudible means causing-asound' tobe emitted. a

The invention will be furtherillustrated by--reference to the drawing in which Fig. l is a sectional view of a preferred device;

Fig. 2 is a partial sectional viewof the valve employed in the present invention; andz i t Fig. 3 is a sectional view of another modification of the invention.

Referring now to thedrawingand first to Fig. 1, numeral 11 designatesa housing having an inlet 12- which is designed to be connected by external threads 13 to a i source of pressure such as a tank and the like. The inlet 11 has a orifice 14 and a recess 15 in which is arranged a felt or cotton filter 16 to prevent passage of debris or dirt and the like into the inlet 12. Connecting to the source of pressure is a first lateral passageway 17 in the housing 11 which is parallel to the inlet 12 and then turns obliquely and terminates in a recess 18. The housing 11 is constructed in two parts which are designated as 19 and 20 and which is held together by a threaded bonnet 21.

The housing 11 encloses a chamber 22 in which is arranged diflerential diaphragms 23 and 24. The diaphragm 23 is held against the lower part 20 by an annular plate 25 which also holds the diaphragm 24 against the upper part 19 of the housing 11.

The diaphragm 23 is providednwith. a port: or: ports 26 whichallows the passageway 17 to communicate through. recess 18 with. a second lateralspassageway. 27i Lateral .passageway 17' and. lateral passageway 27 therefore communicate: with space 28 enclosed by the diaphragms 23 .and. 24.

Arranged in the chamber 22.is a valve actuatingmem' ber 29 which is providedwith a central-bore 30 which runs the length thereof and communicates with the lower portion of chamber. 22. through a lateral bore 31.- The valve. actuatingmember. 29 defines an external shoulder 32 which. providesta seat for'the diaphragm 24". The diaphragms 23. and 24 are held against-=the -valve actu ating member 29' by' a :cylindrical. sleeve 33 which maintains a tight fit and holdsthewtwo diaphragms'snugly against the member 29' with the aid of rubber cement and the like: adhesive...

Embracing .the .upper .end of the member -29--isa biasing means, such v as a helical coil spring 34,-one -'end of twhichbears .against the upper interiorwall---3S--of housing 11 and the other endof which bears-againstthe shoulderv 32. of the member 29.

Attached to an upper end of the housing -1 1-,is-'-an audible warningmeans 36 which maybe a suitable-whistle which communicates with the chamber 22*through an orifice 37 through a lateralpassageway 38 and a longitudinal passageway 39.

Arranged in inlet'12..is a valve generally indicatedas 40 which is provided. witha valve stem 41 -which 1 is adapted. to beurged downwardly on engagement with valve actuating means 29.

The valve 40 is attached to the housing 11' in theinlet 12.. through .mating'. threads. 42 and is sealed therein throughsa deformable sealing member 43.

InuFig. ;2 a detailed, partially sectional view oi the valve: 40 is given... It will be seen that-the valve 40 =is provided with valve stem 41, a sealing member 43, and a threaded collar. 44 provided with threads '42. t The barrel 45' of the valve 4i) encloses a central .bore 46 through which the .valve stem extends. The valve stemis biased upwardly against a shoulder 41' defined by valve stem 41 bya helical coil spring 47 which embraces the valve stem 41. The valve is held in the closed position by the spring 47 to prevent passage of air around the seal 48 and: seat 49.

A further embodiment of the invention is shown in Fig. 3 wherein. numeral 50- designates a valve housing comprised of an upper part 51 and a lower part 52; Arranged .on/the valvehousing 50 isa suitable whistle 53 which :communicates fluidly with a chamber 54 enclosed lgythe housing 50 by-wayof a longitudinal "passageway Thelower part 52 of the housing 50-is provided with external threads 56 and is also provided-with an inlet 57 to allow air or other gas to be led into the-deviceunder pressure; Extendinglaterally from the inlet .57- are passageways 58 which communicate, aswill-be described later, with second passageways 59, the passageways 59 being bored in a third portion 60 of the housing 50".- The upperhport-ion S1 is connected to the middle portion 60 bymeans of threaded bolts 61- while the-middle portion is connected to the lowerportion158j by threaded bolts Arranged in the chamber 54 is a valve actuatingmember generally designated as 63 which is comprised of a longitudinally extending portion 64 -on which is threadably arranged a cap 65 having passageways 66. The cap 65 engages by mating threads 67 with the extension 64. The valve actuating member generally indicated as 63 defines a first shoulder 68 and a second shoulder 69 between which is arranged a diaphragm 70 which is held in the housing 50 between the upper portion 51 and the middle portion 60, as shown.

The extension 64 has an annular projection 71 on which is arranged a second diaphragm 72 which is held in the housing 50 between the middle part 60 and the lower part 52, as shown. The diaphragm 72 is provided with a port or ports 73 which allow fluid communication between passageway 58 and passageway 59 and thence to the space 74 between the diaphragms 70 and 72.

Within the central bore 75 of the valve actuating memberss is arranged a longitudinally extending member 76 which carries a valve such as 40 which has been described with respect to Figs. 1 and 3. Since the valve 40 in this embodiment of my invention is identical to the valve 40 of Figs. 1 and 3, further description thereof need not be had. Suffice to say that the valve 40 is threadably arranged in the member 76 by mating threads 42. The member 76 is threadably connected by mating threads 77 with the lower portion 52 of the housing 50. A passageway 78 running the length of the member 76 communicates through orifice 79 with the inlet 57. An inset member 80 is provided which engages threadably by threads 81 with the member 76 and allows the orifice 79 to be varied at will. A sealing member, such as an O-ring 82, provides a seal and prevents fluid from escaping around the threads 77 and into the chamber 54 below the diaphragm 72. The clearance 83 between the member 76 and the member 64 is vented through lateral ports 84 which communicate with chamber 54.

Surrounding and embracing the member 63 is a biasing means 84, one end of which bears against the shoulder 68 and the other end of which bears against a shoulder 85 of a cylindrical sleeve 86 which rests on the shoulder 63. The member 63 is held snugly against the diaphragm 70 by a nut 87 by mating threads 88.

The device of the present invention works in the following manner with respect to Fig. l:

The device is assumed to be connected by threads 13 to a tank or conduit containing compressed air, gas or the like. It is desired that the whistle 36 blow when the pressure in the tank to which the device is connected falls below a predetermined level. The orifice 14 and the port 30 and passageway 37 would be selected to give the de sired operation with the differential diaphragms 23 and 24. Assuming that 90 pounds supply pressure enters through inlet 12 and passageways 17, the orifices 30 and 37 would be selected so that the pressure below the diaphragm 23 is 6 pounds per square inch gauge while the the pressure above the diaphragm 24 is 2.5 pounds per square inch gauge. The spring 34 would be designed to overcome the difierential pressure of the diaphragms 23 and 24 with the orifices being adjusted as required. As suming that proper adjustment has been made for the selected pressure, then the spring 34 would overcome the diaphragms 23 and 24 when the pressure in inlet 12 falls below a desired point. With the pressure being exerted in the space 28 the assembly 29 would be held off of the valve stem 41 preventing air from passing through the valve 40 into passageway 35 and thence by passageways 38 and 39 and orifice 37 into whistle 36. Thus when the pressure is held constant no signal will be emitted. On the other hand, if the supply pressure in passageway 17 should drop only slightly the spring 34 would overcome the differential diaphragms 23 and 24 which would cause the member 29 to bear against the valve stem 41 and in turn would cause the valve stem 41 and seal 48 to move off of the seat 49 allowing air to pass through the aforesaid passageways and into the whistle 36 causing an alarm. The passageway 17 must be upstream of orifice 14 so that passageway 17 always contains supply pressure. When the whistle is blowing, orifice 14 causes a pressure drop in the inlet. Therefore, the pressure in the inlet will never reach supply pressure as long as the whistle is blowing. However, with the above described arrangement of passages, the pressure in passageway 17 will build up as the supply pressure builds up to a point where the whistle will stop blowing even though the pressure in the inlet is low.

The device of Fig. 3 operates similarly to the device of Figs. 1 and 2. Assuming again that the device is connected by threads 56 to tanks or conduits under pressure the differential diaphragms 70 and 72 would be holding the cap off of the valve stem 41 preventing air or gas from escaping into the passageway 55 and thence through whistle 53 to emit a signal. Thus the helical coil spring 84 tends normally to urge the member 63 downwardly causing the cap 65 to press against the stem 41 unseating the valve. However, the differential diaphragms and 72 on having pressure exerted through passageways 58 and 59 against them in space 74 serves to hold the spring and works thereagainst preventing the contact of cap 65 with the stem 41. When this happens no signal is emitted. However, if the pressure in inlet 57 drops slightly then the spring 84 overcomes the difierential diaphragms 70 and 72 and the cap 65 presses against the stem 41 allowing air to pass from inlet 57 through orifices 79 into passageway 78 and thence through the valve 40, through port 66 and passageway 59 into whistle 53 and to the atmosphere by way of which a sound alarm is emitted.

The device of the present invention is useful where compressed air is employed in oil drilling and other operations where the operators need a warning against low pressures. The device may be used in connection with air brakes, clutch shifting, clutch actuation and other requirements where and/ or gas pressure is employed. The device is advantageous in that it employs only a small amount of air. For example, the size may be regulated to emit approximately 1 to 2 cubic feet of air per minute to blow the whistle. In fact, one of the advantages of our device is that it uses only a small amount of air.

The nature and objects of the present invention having been completely described and illustrated, what we wish to claim as new and useful and to secure by Letters Patent 1. A low pressure warning device adapted to be connected to a source of pressure which comprises, in combination, a housing enclosing a chamber provided with an inlet, a first lateral passageway in said housing adapted to communicate with said source of pressure, a second lateral passageway in said housing communicating said chamber with said first lateral passageway, a movable valve actuating member provided with a central bore arranged in said chamber, a first diaphragm in said chamber, a second diaphragm spaced apart from said first diaphragm in said chamber provided with ports communicating fluidly said first and second passageways, said diaphragms being operatively connected to said valve actuating member, a valve arranged in said housing in fluid communication with said inlet having a valve stem normally in inoperative relationship with said valve actuating member, biasing means embracing said valve actuating member normally urging said valve actuating member toward and holding said valve actuating member into engagement with said valve stem, and an audible warning means arranged on said housing and fluidly connected to said chamber adapted to be actuated by said biasing means overcoming pressure exerted through said passageways in the space between said diaphragms.

. 2. A device in accordance with claim 1 in which the valve is arranged within the central bore.

3. A device in accordance with claim 1 in which the valve is arranged in the inlet.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,417,168 Harris May 23, 1922 2,250,077 Henry July 22, 1941

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