US2490555A - Valve actuating mechanism - Google Patents

Description

L. W. SONGER VALVE ACTUATING MECHANISM Filed Oct. 28, 1944 Dec. 6, 1949 Inventor-z Leo W. Sorgen 5 His /Bctrtcw'rwe9` Patented Dec. 6, 1949 -fAT ENT" F FICE VALVE ACTUATING MECHANISM LeoW. Songer, Scotia, N. ik, assignor izo-Generall Electric Company, a. corporation of Newy York Application October 2,8, 1944, Serial No. 560,814

(Cl. 74A- 516) Claims.

The present' invention relates to valve actuating mechanisms including a hydraulic motor or power agency and a lever for positioning a valve. The invention is of particular interest in connection with unbalanced valves which have to be opened against the force of fluid pressure on one side, thereof. In order to overcome the unbalanced force it has been customary heretofore to provide a valve with a main valve member and a pilot valve member, which latter is opened first t0 balance substantially the pressure across the valve. In some instances even the actuation ofv the pilot valve of this type requires a large hydraulic motor.

The object-of my invention is to provide an improved construction and arrangement of valve actuating mechanisms whereby the valve may be fully opened or closed by a comparatively small hydraulic motor. This is accomplished in accordance with my invention by the provision of a special lever mechanism between the hydraulic motor and the valve to be operated. Such lever mechanism in a preferred embodiment includes a lever which has portions connected to a hydraulic motor and a valve to be actuated and other spaced portions alternately supported on spaced fulcrums by slot and pin connections. A lever of this type provides for a large lever ratio to start opening or closing of the valve and a small lever ratio for subsequent movement of the valve.

For a better understanding of` what I believe to be novel and my invention, attention is. directed to the following description and the claims` appended thereto in connection with the accompanying drawing.

in the drawing Fig. l illustrates a diagrammatic view of an arrangement embodying my invention; and Figs. 2 and 3 show parts of the arrangement of Fig. 1 in different operating positions.

The arrangement comprises a valve l having a casing with an inlet 2 for receiving iluid under pressure and an outlet 3 through which fluid is discharged. The outlet has two branches i and 5 connected to separate turbines or turbine parts S' and l respectively. The flow from the inlet 2 to the outlet 3 is controlled by a movable valve member including a main valve member 3 and a pilot'valve member 9. The pilot valve member is seated on the main valve member and the latter is seated on the casing. The valve members are connected to a stem I IJ. In the position shown both valve members are closed. Upon upward movement ofthe stem l0 the pilot valve 2. member is rst opened, permitting the flow of operating iiuidY fromthe inlet`2 through channels 5l ofthe main. valveV member into the outlet 3; thus balancing at least" partly the pressure across the main valve member. Upon further upward movement of the stem lil the main valve member 8 `is forced away from its seat. The initial opening movement, that is, the cracking open ci the valve, requires a considerable force while only a smaller force is needed to force the valve member through theremaining part of the opening stroke. This alsoapplies to the closing movement, especially with regard to stop valves of' turbines which often are held fully open for a considerable period of time. During this long period the valve stem may stick to thecasingldue to deposits formed between them. 'Ihis requires a considerable force to start closing movement of*v the valve and only a smaller force to complete the closing movement.

According to my invention, as pointed out above, this is accomplished by a special lever mechanism for connecting the valve to a power agency. The power agency is in the form of a hydraulic motor having a cylinder I2 and a piston i3 with a stem Hl` slidably disposed in the cylinder; The' piston I3 isbiased downwardby a compression spring l 5. Fluid under pressure is supplied to theunder side of the piston through an opening I6 in the casing and' leakage nuid is drained from the upper side of the piston through a channel. Il in the casing. The stem le ofthe servomotor is connected to the righthand end of a lever I8 which has an intermediate portion connected by a crossheadv I9" to the lower end ofthe valve stem I0.' The crosshead I9 in the; present example is guidedon projections 20 ci a plate 2l secured to the valve casing,

'The left-hand' end oi' the lever according to my invention has spaced portions connected to fulcrums by mea-ns ofpin and. slot connections. More specifically, the left-handend of the lever has spaced slots 22 and 23. The slot 22,is.connected by a pin 24 to a link or fulcrum 25 and theSlot 23 isconnected by a pin or pivot 26 toV another linlror fulcrum 2,1. The links 25, 21 in the present exampleaije pivotally supported on the valve casing.

During operatiomoilor like-operating medium under pressure iS supplied,to1the-pressurecham ber below thepiston I3 of the servomotor toeffeet upward movementcf the latter in order to open the valve. During the first part of this up.- wardmovement the lever Iapivotson the pin 2t, thus providing for a relatively large lever ratio, i. e. a large mechanical advantage, and a considerable force on the valve stem. During this counter-clockwise turning movement of the lever about the pivot 24 the slot 23 moves gradually downward relative to the pivot 26. In a certain position (Fig. 2) of the lever the upper end of the slot 23 engages the pivot 26. From then on the pivot 26 becomes the fulcrum for the lever, that is, during the final opening stroke the lever turns about the pin26 and the slot 22 moves upward relative to the pin 24 (Fig. 3) until the valve is fully open. During the first part of the closing movement of the valve the pin 24 acts as a fulcrum (Fig. 3), thus providing for a large mechanical advantage until the lower end of the slot 23 engages the pin 26 whereupon the latter acts as the fulcrum for the lever during the final closing movement of the valve.

If however stem IU while in the open position is capable or" moving freely in its bushing, during the iii-st part of the closing movement lever I8 fulcrums first about pin 26 until the upper end of slot 22 engages pin 24 whereupon the latter acts as a fulcrum during the final closing movement of the valve.

Having described the method of operation of my invention, together with the apparatus which I now believe to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. In combination with a rst movable member adapted to be actuated in substantially linear translational movement, actuating means for said member comprising a motor having a second actuating member adapted to produce linear reciprocating motion in a direction substantially parallel to the path of the rst member and linkage means connecting said second member to said rst member, said linkage including lever means having a rst end portion connected to the second member and an intermediate portion connected tojthe first member and two spaced fulcrum means each connected to the lever on the same side of the rst member and remote from said rst lever end portion, said fulcrum means engaging the lever through lost motion connections so arranged that initial movement of said second actuating member in either direction produces a force on the first member with a large mechanical advantage while subsequent movement of the actuating member in the same direction produces movement of the rst member with a smaller mechanical advantage.

2. The combination of a first movable member to be actuated, actuating means for said member comprising a motor having a second actuating member adapted to produce substantially linear reciprocating motion and llinkage means connecting said second member to said first member, said linkage including lever means having an intermediate portion connected to the rst member and a first end portion connected to said second member and a second end portion having cooperatively associated therewith variable fulcrum means including a first fulcrum connected to said third end portion of the lever by a first lost motion connection and a second fulcrum connected to the lever by a second lost motion connection at a point intermediate said nrst connection and the connection with said iirst member.

3. The combination of a first movable member to be actuated, actuating means for said member comprising a motor having a second actuating member adapted to produce substantially linear reciprocating motion and linkage means connecting said second member to said rst member, said linkage including lever means having an intermediate portion connected to the rst member and a rst end portion connected to said second member and a second end portion having cooperatively associated therewith variable fulcrum means including a rst fulcrum connected to said second end portion of the lever by a rst lost motion connection and a second fulcrum connected to the lever by a second lost motion connection at a point intermediate said rst connection and the connection with said irst member, said lost motion connections being constructed and arranged so that initial movement of the second member in either direction produces a force on said first member with a large mechanical advantage while subsequent motion of the second member in the same direction produces a force on the iirst member with a smaller mechanical advantage.

4. The combination of a rst movable member to be actuated, actuating means for said member comprising a motor having a second actuating member adapted to produce substantially linear reciprocating motion and linkage means connecting the second member to the first member including a lever having rst and second spaced portions connected to the rst member and the second member respectively, and variable fulcrum means associated with a third portion of the lever on the side of the rst lever portion remote from the second portion, said variable fulcrum including a first link connected by a lost motion connection to the third lever portion at a point remote from the connections with the first and second members and a second pivoted link connected by a second lost motion connection to the lever at a point between the iirst lost motion connection and said connectiton with the rst member.

5. The combination of a rst movable member to be actuated, actuating means for said member comprising a motor having a second actuating member adapted to produce substantially linear reciprocating motion and linkage means connecting the second member to the first member including a lever having rst and second spaced portions connected to the rst member and the second member respectively, and variable fulcrum means associated with a third portion of the lever on the side of the first lever portion remote from the second portion, said variable fulcrum including a first link connected by a lost motion connection to the third lever portion at a point remote from the connections with the first and second members and a second pivoted link connected by a second lost motion connection to the lever at a point between the rst lost motion connection and said connection with the rst member, said lost motion connections being constructed and arranged so that initial movement of the second member in either direction causes the lever to fulcrum on the second lost motion connection while subsequent movement of said second member in the same direction causes the lever to fulcrum on the rst lost motion connection.

LEO W. SONGER.

(References on following page) 5 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 368,347 Massey Aug. 16, 1887 374,786 Everitt et ai Dec. 13, 1887 518,700 Reynolds Apr. 24, 1894 1,000,439 Buck Aug. 15, 1911 10 1,382,020 Scoville June 21, 1921 1,547,133 Strickland July 21, 1925 Number Number

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