US2746711A

US2746711A - Valve actuating means

Info

Publication number: US2746711A
Application number: US281566A
Authority: US
Inventors: Clarence E Kenney; Charles L Ringle
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1952-04-10
Filing date: 1952-04-10
Publication date: 1956-05-22
Anticipated expiration: 1973-05-22

Description

May 22 1956 c. E. KENNEY ET AL 2,746,711

VALVE ACTUATING MEANS Filed April 10, 1952 & 2 i Q E Mar/J OVZWWC ai Qua QM 2 WWW @wwm United States Patent VALVE ACTUATING IVIEANS Clarence E. Kenney, Hartland, and Charles L. Ringle,

Milwaukee, Wis., assignors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Application April 10, 1952, Serial No. 281,566

3 Claims. (Cl. 251-26) This invention relates generally to control apparatus for valves and the like, and is particularly concerned with the provision of an improved valve actuating mechanism designed to insure a desired valve operation.

One such operation, by way of example, occurs in connection with the use of a safety valve positioned in a header line to immediately shut ofif a flow of fluid in response to attainment of a predetermined condition. In order to obtain a rapid and complete closing of such a valve, it is usually necessary to periodically effect at least some movement of the valve in order to prevent a sticking or binding of parts.

Heretofore safety valves of this type have been thus moved by mechanical means such as a jackscrew which is connected directly to the valve structure and provided with a handwheel. Rotation of the handwheel causes movement of the jackscrew and valve, thereby keeping the valve free from binding. Mechanical methods are slow and cumbersome, and in addition cannot be readily incorporated in systems employing hydraulic valve actuating mechanisms.

The present invention has as an object to provide a valve with a hydraulic actuating means incorporating features of improvement enabling an operator to readily periodically check and insure proper valve operation.

Another object of this invention is to provide a valve with ahydraulic valve actuating means incorporating features of improvement enabling an operator to readily periodically move said valve between predetermined limits, and to readily determine without the aid of visible means, when said movement has been elfected.

Other objects and advantages will appear from the following description of an embodiment of the invention, reference being had to the accompanying drawing, in which:

Fig. l is a vertical cross section of a hydraulically operated header line safety valve embodying the invention, with the valve shown in its fully closed position; and

Fig. 2 is similar to Fig. 1 except that the valve is shown in its fully open position in solid lines and in its partially closed position in broken lines.

As shown in Fig. l of the drawing, the invention is applied to a steam line control valve structure comprising a conventional housing 1 providing an annular valve seat 2 and an annular cage 3 coaxially spaced from seat 2 for guiding coaction with a safety or main valve 4. Housing 1 forms a part of a steam line 6, which for purposes of illustration is to be considered as placing a steam turbine (not shown) in communication with a boiler (not shown).

Valve 4 comprises a hollow body portion 7 defining an internal chamber 8 slidably receiving a terminal end of valve stem 9. This end of valve stem 9 carries an equalizer valve 11, which coacts with an annular seat 12 formed on an inner surface of body portion 7 forming the bottom wall of chamber 8. Body portion 7 is also provided with equalizer passages 13 placing chamber 8 in communication with the passage 6 on opposite sides of that portion of valve 4 adapted to engage seat 2.

2,746,711 Patented May 22, 1956 ice Steam flow through passages 13 and chamber 8 is controlled by equalizer valve 11.

With the parts positioned as shown in Fig. 1 the upper end of valve stem 9 is spaced from the inner top Wall of chamber 8. Consequently, an upward movement of valve stem 9 results first in an upward movement of equalizer valve 11 which allows steam to flow through passages 13 and chamber 8 thus tending to equalize the pressure on the upstream and downstream sides of the valve.

Continued upward movement of stem 9 engages the upper end of the stem with the top wall of chamber 8 which in turn moves valve 4 upward from seat 2 and into cage 3, the fully open position being shown in solid lines in Fig. 2. Valve stem 9 is slidably mounted in a guide bearing member 15 carried by housing 1 in coaxial alignment with seat 2 and cage 3. The valve stem extends below housing 1 into a depending liquid con- Bearing member 16 includes a packing gland 18, which coacts with valve stem 9 to provide a seal therefor. A helical compression spring or element 19 which surrounds valve stem 9, has one end engaging the inner surface of bearing member 16 and has its other end engaging the inner top side of servomotor piston 17. Spring 19 is a means for biasing valve 4 in a downward direction toward its closed position.

The lower end of cylinder 14 is closed by a detachable liquid tight cover plate 21 provided with a sleeve bushing 22 slidably receiving a second element, coaxial valve stem extension, or part 23, which may also be considered as an element, second valve, or a second control element. Two

bushing retainers

24 and 26 surround top and bottom portions, respectively, of bushing 22 and provide radial support therefor. In addition, a thrust collar member 27 coacts with the enlarged lower end of said bushing and serves to prevent a longitudinal movement thereof relative to cover plate 21. Retainer 24 is provided with bores 25 which extend coaxially therethrough and place the bottom portion of cylinder 14, that is the space beneath piston 17, in communication with an annular space 28 provided between the outer Wall of bushing 22 and the surrounding inner surface portion of cover plate 21. In addition, bushing 22 is provided with radial bores 29 which open into the lower portion of space 28. With the parts positioned as shown in Fig. l, valve stem extension 23 closes bores 29 thus preventing a flow of fluid therethrough from space 28. In this connection,

items

25, 28 and 29 can be considered as comprising drain passage means.

An automatic pressure responsive trip device or trip manner (not shown).

31, a pair of diametrically

opposite chambers

32 and 33, and an upper chamber 34 which overlies space 31Lv and the

chambers

32 and 33. Chamber 32 is in com-.

munication with the interior of cylinder 14 at a point beneath piston 17 by means of a bore 36, and with space 31 by means of a bore 37. Chamber 34 is in communication with cylinder 14 at a point above piston 17 by means of a bore 38, and with the open upper end-of,-

The portion of cylinder 14 above piston 17 is also in communication with a fluid return C01ldllit.-.:f

space 31.

39 by means of a bore 41. Chamber 33 is in communication with space 31 by means of a bore 42 and with a fluid supply conduit 43 by means of a bore 44. Conduit 43 communicates with a source of liquid under pressure (not shown) and embodies a flow restriction 46 therein. Cylinder 14, piston 17 and the source of liquid therefor (not shown) can be considered as comprising an actuating or operating mechanism for valve 4.

A cylinder valve 47 is reciprocably mounted in space 31 and provided with a peripheral groove 48 which, when valve 47 is positioned as shown, places chamber 33 in communication with chamber 32. Valve 47 is provided with an upwardly extending coaxial stem 49 having its upper end reciprocably mounted in a tubular guide element 51 projecting inward from a cover member 52 closing a coaxial opening in the top wall of housing 30. Stem 49 is provided with an annular shoulder 53 adapted to abut the inner end of guide 51 and thereby limit the upward movement of valve 47. Shoulder 53 is somewhat larger than guide 51 and presents a seat for one end of a compression spring 54 which surrounds guide 51 with its other end bearing against the inner surface of the cover 52. Housing 30 is also provided with a bottom cover member 56 having an opening 57 therethrough receiving the end of a conduit 58 communicating with a governor controlled source of pressure fluid (not shown).

With the various parts positioned as shown in Fig. l, the pressure of the fluid in conduit 58 has just moved valve 47 to its uppermost position against the force of spring 54, thereby placing cylinder 14 in communication with conduit 43 through

bores

36, 37, annular groove 48 in valve 47, and bores 42, 44. The opening of valve 4 is not instantaneous due to the constriction 46 in conduit 43. However, the fiow of pressure fluid into cylin der 14 results in a fairly rapid opening of valve 4 to its solid line position in Fig. 2, movement of the valve in this direction being limited by

shoulders

67, 68 provided on valve stem 9 and bearing member 15, re spectively, the coaction of which shoulders also serves to seal off the interior of steam line 6 from its external surroundings.

When valve 4 has moved to its fully open position (see Fig. 2), the valve stem extension 23 will also have moved upward placing the interior of cylinder 14 in communication with the interior of bushing 22 by means of bores 25, annular space 28, and radial bores 29. The thrust collar member 27 detachably receives means operatively associated with the chamber comprising an enlarged end portion 59 of a conduit 61 which embodies a normally closed, manually actuated first element or valve 62 and has its opposite end connected with an intermediate portion of return conduit 39. Valve 62 may also be considered as a manually operable part, device, or first control element. In addition, the bottom cover plate 21 of cylinder 14 is provided with a bore 63, which in conjunction with a conduit 64 including a valve 66 places the interior of cylinder 14 in communication with conduit 61 at a point between valve 62 and the enlarged end 59. Valve 66 is of the spring biased pressure relief type and is positioned in conduit 64 to open in response to attainment of a predetermined pressure in conduit 61, as hereinafter pointed out. In this connection, the combination of valve stem extension 23, bores 25, annular space 28, radial bores 29 and valve 62 may be considered as comprising a selectively operable means, selectively operable apparatus, or hydraulic control means.

The movement of valve 4 to its fully open position results in fluid flowing into and filling the bores 25, annular space 28, that portion of sleeve 22 beneath valve stem extension 23, and that portion of conduit 61 on the cylinder side of valve 62. It is extremely important to keep the valve 4 conditioned for immediate closure by the action of spring 19 in the event conditions arise causing the governor (not shown) to remove the source of fluid pressure acting on the bottom of valve 47. Of course, when such conditions arise, spring 54 first acts to move valve 47 downward sufficiently to place that portion of cylinder 14 beneath piston 17 in communication with return conduit 39, such communication being effected through bore 36, chamber 32, bore 37, space 31, chamber 34, bore 38, the portion of cylinder 14 immediately above piston 17, and bore 41. This results in an immediate reduction of the pressure of fluid beneath piston 17, whereupon spring 19 effects a closure of valve 4.

Normally, conditions necessitating the closing of valve 4 occur only infrequently, and consequently a sticking or binding of parts due to corrosion or other causes may prevent a timely closing of the valve. However, in accordance with this invention, a valve such as that designated 4 may be conditioned for immediate closing simply by periodically opening and closing valve 62. For example, with the valve 47 positioned as shown in Fig. 1 and the valve 4 positioned as shown in solid lines in Fig. 2, the opening of valve 62 results in a decrease in pressure of the fluid acting on the bottom of piston 17 (note the constriction in conduit 43) and a consequent closing movement of valve 4, such movement continuing until valve stem extension 23 closes radial bores 29 as indicated by the broken line position of valve 4 shown in Fig. 2, which can be considered as a third position. In this connection, the fully open and fully closed positions of valve 4 may be considered as first and second positions. During this partial actuation of valve 4, relief valve 66 remains closed, and the closing movement of valve 4 ceases when it reaches its broken line position in Fig. 2. This partial closing of valve 4 is such as will afford only a slight and immaterial throttling of the fluid flowing through line 6. However, even such a throttling is suflicient to produce a clearly audible hissing sound which informs the operator that the valve 4 has reached its partially closed position, whereupon the operator should immediately proceed to close valve 62. The closing of valve 62 results in an immediate increase in the pressure of the fluid beneath piston 17 and a consequent movement of valve 4 to its fully open position shown in solid lines in Fig. 2. In this connection, it may be desirable to provide a pressure relief bypass such as indicated by bore 63, line 64 and valve 66 for the purpose of minimizing any shock that might result from a sudden closing of valve 62, and what is more important, for the purpose of serving as a hydraulic pressure release on the fluid cushion beneath valve stem extension 23, so that the valve 4 can be rapidly closed as required when fluid is drained from the lower end of cylinder 14 through the automatic pressure responsive trip device.

The valve conditioning apparatus of this invention may be readily applied to a simplified single acting valve actuating mechanism without in any manner impairing the operation of such mechanism. In addition, the operator is positively informed as to when the main valve has been moved the predetermined extent deemed necessary to insure a prompt automatic closing of the valve in response to attainment of a selected abnormal condition which acts through a governor or other suitable means (not shown) to remove the force holding the trip valve 47 in the position shown in Fig. 1. Moreover, all this is readily accomplished with a minimum of expense and apparatus affording a high degree of simplification as to its construction, application and operation. Further, those skilled in the art will readily appreciate that apparatus embodying the invention may be readily applied to valve actuating mechanisms quite different from the practical embodiment herein shown and described for purposes of illustration.

It is claimed and desired to secure by Letters Patent:

1. In combination with a valve having means operable to open and close said valve, said means including a cylinder, a piston reciprocally disposed within said cylinder and connected to said valve for movement therewith, a cover plate enclosing one end of said cylinder defining with said cylinder and said piston a fluid pressure confining chamber, and means selectively communicating said chamber with a source of fluid pressure for moving said piston to open said valve, and with a drain for moving said piston to close said valve, apparatus for etfecting a closing movement of said valve to a predetermined partially closed position comprising a drain passage communicating with said chamber through said cover plate and including a manually operable drain valve for controlling the outflow of fluid through said drain passage, a stem connected to said piston and insertable into and movable within said drain passage, said stem moving to a position closing said drain passage as said valve moves in a closing direction to said predetermined closed position, and a pressure relief bypass passage for said drain passage connecting said drain passage upstream of said drain valve to said chamber.

2. In combination with a valve having means operable to open and close said valve, said means including a cylinder, a piston reciprocally disposed within said cylinder and connected to said valve for movement therewith, a cover plate enclosing one end of said cylinder defining with said cylinder and said piston a fluid pressure confining chamber, and means selectively communicating said chamber with a source of fluid pressure for moving said piston to open said valve and with a drain for moving said piston to close said valve, apparatus for effecting a closing movement of said valve to a predetermined partially closed position comprising a drain passage communieating with said chamber through said cover plate and including a manually operable drain valve for controlling the outflow of fluid through said drain passage, a stern connected to said piston and insertable into and movable within said drain passage, said stem moving to a position closing said drain passage as said valve moves in a closing direction to said predetermined closed position, and a 40 pressure relief bypass passage for said drain passage conmeeting said drain passage upstream of said drain valve to said chamber, said drain passage including a relief valve responsive to pressures in said drain passage in excess of a predetermined pressure to open said relief valve and communicate said excess pressures to said chamber.

3. In combination with a valve having means operable to open and close said valve, said means including a cylinder, a piston reciprocally disposed within said cylinder and connected to said valve for movement therewith,

3. In combination with a valve having means operable to open and close said valve, said means including a cylinder, a piston reciprocally disposed within said cylinder and connected to said valve for movement therewith, a cover plate enclosing one end of said cylinder defining with said cylinder and said piston a fluid pressure confining chamber, and means selectively communicating said chamber with a source of fluid pressure for moving said piston to open said valve and with a drain for moving said piston to close said valve, apparatus for eifecting a closing movement of said valve to a predetermined partially closed position comprising a drain passage communicating with said chamber through said cover plate and including a manually operable drain valve for controlling the outfiow of fluid through said drain passage, a stem connected to said piston and insertable into and movable within said drain passage, said stem moving to a position closing said drain passage as said valve moves in a closing direction to said predetermined closed position, and a pressure relief bypass passage for said drain passage connecting said drain passage upstream of said drain valve to said chamber, said drain passage including a relief valve biased to a closed position by an expanded spring and responsive to pressures in said drain passage in excess of a predetermined pressure to compress said spring to open said relief valve and communicate said excess pressures to said chamber.

Troy Nov. 17, 1942 Thurber Apr. 21, 1953