US 3610573 A
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United States Patent 2,850,260 9/1958 Perazone 4. 251/203 X FOREIGN PATENTS 770,610 7/1934 France 25l/l67 Primary Examiner-Harold W. Weakley Attorneys-Harry G; Martin, Jr. and 1. Raymond Curtin ABSTRACT: The valve casing has openings in opposite sidewalls communicating with conduits in a pipeline. A stem is .mounted in the casing for rotation and axial sliding movement. A valve mechanism is carried at the inner end of the stem and includes valve plates movable upon rotation of the stem in one direction into engagement with the sidewalls of the casing to close the openings therein. Spring means is connected to the valve plates for urging the same away from the sidewalls upon reverse rotation of the stem. The entire valve mechanism is movable into and out of registration with the sidewall openings upon axial sliding movement of the stem. The valve mechanism also includes levers which, upon reverse rotation of the system, serve to pry the valve plates away from the opposite sidewalls in the event the valve is closed with high pressure within the casing.
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DAVID E. ROBERTSON BY @MW/ ATTORNEY VALVE STRUCTURE BACKGROUND OF THE INVENTION There are situations in which it is desirable to use a valve in a pipeline embodying an arrangement, when the valve is opened, to provide a direct full flow through valve passage dimensioned comparable to the pipeline. Such valves are commonly known as gate valves. Such valves are expensive due to the structure embodied in the valve. The interior of the gate valve is formed with converging sides in which the flow openings are formed. A stem is threaded into the valve body and carries at its inner end a pair of valve plates and a cam member. The plates are moved downwardly into registration with the side openings upon rotation of the valve stems, and thereupon the cam structure forces the valves against the sides of the body to close the openings therein.
The action of such gate valves is slow in that all the movement imparted to the valve members or discs is by way of rotation of the valve stem. The marginal area about the openings in the sides of the valve body form the seats of the valve, and they must be initially machined and thereafter maintained in perfect condition, and likewise the confronting surfaces of the valve discs. The entire valve structure is usually formed of metal. It is an expensive and time-consuming operation to resurface the valve seats in such a valve structure.
This invention has as an object a valve structure which is particularly intended to be used in large diameter pipelines, which is particularly economical to build, and which is rapid in both closing and opening operations. Also, the valve structure includes means, which functions to effect opening of the valve, where the valve casing is pressurized under high pressure when the valve is closed.
SUMMARY OF THE INVENTION The casing is in the form of a weldment readily fabricated from flat metal stock without machining. The casing is preferably of rectangular form with opposite sidewalls provided with flow openings for connection to the line. A valve assembly is mounted on the end of a stem and includes valve plates movable laterally into and out of engagement with the sidewalls to open and close the openings therein. The stem is mounted in the casing for rotation and axial movement. Lateral movement of the valve plates is effective by rotation of the stem and the entire valve assembly is movable, normal to the axis of the flow openings, into and out of registration therewith. The valve assembly also includes a lever arrangement operable upon rotation of the stem to forcibly pry the valve plates away from the casing sidewalls in the event the valve is closed when highly pressurized.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a valve structure embodying my invention;
FIG. 2 is a vertical sectional view taken on line 2-2 of FIG. 1 showing the valve in closed position;
FIG. 3 is a view of the lower portion of FIG. 2 showing the valve plates disengaged from the sidewalls of the housing;
FIG. 4 is a view similar to FIG. 3 showing the valve-operating mechanism elevated in the housing for clearthrough flow passage;
FIG. Sis a view taken on line 5-5 of FIG. 1;
FIG. 6 is a view taken on a line corresponding to line 66 of FIG. 2;
FIG. 7 is a view taken on line 7-7 of FIG. 2;
FIG. 8 is a view taken on line 8-8 of FIG. 3;
FIG. 9 is an enlarged view taken on line 9-9 of FIG. 8; and
FIG. 10 is a view similar to the lower portion of FIG. 2 showing the valve plates pried away from the casing sidewalls.
DESCRIPTION OF THE PREFERRED EMBODIMENT For economy of construction, the valve casing may be fabricated as a weldment from flat steel plate, resulting in a rectangular configuration, comprising upper and lower end wall plates 20,21; opposed sidewall plates 22,23; and intermediate sidewall plates 24,25. The opposed sidewall plates 22,23 are formed with openings 27 which communicate with the conduit in the pipeline in which the valve is installed. Preferably, cylindrical sleeves 30 are welded to the sidewalls 22,23 for convenient welded connection to the pipes in the line upon installation of the valve. A collar 31 is welded into the top end plate 20 and provided centrally with a bore in which a stem 33 is rotatably and slidably mounted. A gland nut 34 is provided for compressing a packing 35 about the stem. The stem has an outwardly extending portion 37 provided with a noncircular portion 38 for the reception of a wrench or other tool to effect operation of the stem 33.
The lower portion of the stem 33 is threaded to receive nuts 40,41 which serve to locate a cam block 43 against axial movement relative to the stem. The stem is journaled in the cam block 43, and the nuts 40,41 are maintained in adjusted position as by being brazed onto the stem. The stem 33 has threaded engagement with a plate 45 of rectangular form. The end edges of the plate 45 terminate in close proximity to the casing walls 24,25. The opposite side edges 46 of the plate 45 are spaced inwardly a distance from the plates 22,23. (See FIGS. 2 and 6.) A valve plate 47 is arranged in confronting relation to each of the sidewalls 22,23.
The valve plates are positioned between the side edges 46 of plate 45 and the adjacent walls 22,23. Each of the plates 47 is provided with a cam-engaging block 48, welded or otherwise fixed thereto. The blocks 48 have downwardly diverging surfaces 50 engaged by inclined surfaces formed on the sides of the cam block 43 carried by the stem 33. Eye screws 53 are threaded into the ends of the blocks 48 for the reception 0 tension springs 55.
With the lower edges of the valve plates 47 positioned on the bottom wall 21 of the casing, and plate 45 positioned on the blocks 48, rotation of the stem 33 in one direction will cause the stem and cam block 43 to be moved upwardly toward the plate 45, camming the valve plates 47 laterally toward the sidewalls 22,23. Referring to FIGS. 8 and 9, each valve plate 47 is formed with an annular groove in which there is molded an annular gasket member 57 of neoprene or other suitable yielding material. The gaskets 57 are dimensioned to overlie the marginal areas about the openings 27 in the sidewall plates to effectively seal off the openings. This condition is illustrated in FIG. 2 of the drawings. When the stem 33 is rotated in the reverse direction, the stem 33 and cam block are moved downwardly relative to plate 45, permitting the springs 55 to draw the plates 47 inwardly out of engagement with the sidewalls 22,23 as shown in FIG. 3.
With the valve plates 47 disengaged from the sidewalls 22,23 and moved inwardly therefrom, the entire valve assembly can be drawn upwardly by stem 33 toward the top wall 20 of the casing, as illustrated in FIG. 4, permitting direct full flow of fluid through the openings 27.
While this valve can advantageously be used in any fluid line, it was developed particularly for use on refrigeration equipment, especially such equipment consisting of a centrifugal compressor, a condenser, an economizer, and a cooler. It is advantageous to be able to isolate certain of these components to trap the refrigerant therein, which permits maintenance work to be performed on the other components without losing the refrigerant. For example, these valves are used in the line from the condenser to the economizer, in the line from the economizer to the second stage of the compressor, and in the line from the economizer to the cooler.
In such use on refrigeration equipment, the valve casing may contain a substantial quantity of refrigerant when the valve is closed to the position shown in FIG. 2. In the event that the temperature of the trapped refrigerant rises, pressure within the casing is developed, perhaps to a high value. In that situation, effecting relative axial movement between cam block 43 and plate 45 by reverse rotation of the stem 33, would not result in the springs 55 being able to draw the valve plates 47 out of engagement with walls 22,23.
That problem is solved by providing each valve plate 47 with a lever 60. These levers are pivotally mounted on a pin 61, supported in brackets 62, fixed to the valve plates in proximity to the upper ends thereof. The levers 60 extend from the pivot pins 61 inwardly over the plate 45. The levers have shorter end portions extending from the pivot pins 61 toward the walls 22,23. With the valve closed, as shown in FIG. 2, the lower end of the stem 33 is in close proximity with the bottom wall 21 of the casing. Upon reverse rotation of the stem, the lower end of the stem is moved into engagement with the bottom wall 21, and the plate 45 is threaded upwardly on the stem. This upward movement of the plate 45 results in the engagement of the inner ends of the levers 60 by plate 45, moving them upwardly and swinging the outer end portions 65 of the levers outwardly through slots 66, formed in the upper end portions of the plates 47, into engagement with the walls 22,23. This action results in the upper portions of the plates 47 being pried inwardly away from the walls 22,23 as shown in H0. l0. This results in breaking the seal between the valve plates 47 and the sidewalls 22,23 providing an opening as at 70 (H6. releasing the built-up pressure within the casing, permitting the springs 55 to move the valve plates 47 to the disengaged position shown in FIG. 3. The stem 33 may be then drawn axially outwardly to move the entire valve assembly upwardly, as shown in FIG. 4.
A stop collar 73 may be fixed to the stem 33 to limit upward movement of plate 45. Due to the fact the valve plates 47 are moved laterally into and out of sealing engagement with the casing sidewalls without any movement in a direction normal to the axis of the flow openings 27, there is no damage or wear imparted to the gaskets 57. Also, upon movement of the valve assembly into and out of registration with the flow openings 27, the valve plates 47 are drawn inwardly out of engagement with the sidewalls of the casing. Accordingly, the valve is free from maintenance for an extended period of operation.
l. A valve structure comprising a casing having opposed sidewalls, each formed with an opening for connection to a conduit, a stem mounted in said casing, a valve mechanism carried by the inner end of said stem and including a pair of valve plates disposed in confronting relation to said opposed sidewalls respectively, said stem being mounted in said casing for rotation about its axis and for axial sliding movement in a direction normal to the axis of said openings in the casing and having a portion extending exteriorly of the casing, whereby upon axial sliding movement of said stem, said valve plates are moved into and out of registration with said openings, said valve mechanism also including a cam member and a plate member mounted on said stem intermediate said valve plates, said stem being rotatable in both of said members, one of said members being fixed against axial movement relative to said stem, the other of said members having threaded engagement with said stem, camengaging blocks fixed to the confronting surfaces ofsaid valve plates and being disposed intermediate said members, said members being cooperable with said blocks, upon rotation of said stem in one direction, to move said valve plates into engagement with said opposed sidewalls of said casing to close the openings therein, a pry member pivotally mounted on each of said valve plates, said threaded member being movable into engagement with said pry mem bers upon reverse rotation of said stem, said pry members being operable upon such engagement to pry said valve plates inwardly from said opposed walls.
2. A valve structure as set forth in claim 1 wherein said cam member is fixed on said stern against axial movement relative thereto.
3. A valve structure as set forth in claim 1 wherein said plate member is threaded upon said stem.
4. A valve structure as set forth in claim 1 wherein said plate member is threaded on said stem and positioned upwardly from said cam member.
5. A valve structure as set forth in claim 1 wherein said pry members consist of a lever pivotally mounted intermediate the ends thereof to each of said valve plates, said levers havin portions extending inwardly for engagement by said threade