US3252472A - Unloading valve - Google Patents

Description

May 24, 1966 F. J. NATHO UNLOADING VALVE Original Filed Sept. lO, 1962 2 Sheets-Sheet l AGENT P. J. NATHO UNLOADING VALVE May 24, 1966 2 Sheets-Sheet 2 Original Filed Sept. lO, 1962 INVENTOR. PAUL J. NATI-IO United States Patent O 3,252,472 UNLOADING VALVE Paul Il. Natho, Houston, Tex., assiguor to ACF Industries, Incorporated, New York, N.Y., a corporation of New .llersey rginal application Sept. 10, 1962, Ser. No. 222,275, now Patent No. 3,171,628, dated Mar. 2, 1965. Divided and this application June 11, 1964, Ser. No. 374,467

Claims. (Cl. 137-102) This application is a division of my copending application Serial Number 222,275, tiled on September 10, 1962, issued March 2, 1965, as U.S. Patent Number 3,171,628.

This invention relates to a system for the control of an offshore or other remotely located hydraulically operated valve and the essential components therefor.

The discovery of petroleum products in offshore and other isolated locations has resulted in changes of technology in the completion of the well. In some instances, the Wellhead control units are located above the surface of the Water and the well is completed very much similar to a Well located on land. However, in such instances,

due to the inaccessibility of lthe location', the trend has been toward the use of automated equipment which can be automatically controlled from a central point. In other cases, the Wellhead control unit is located under the surface of the water, and in such cases it is necessary to use a new technology to complete the well. When the wellhead completion unit is located under the water, the wellhead and control system may be encased in a canister isolating it from the sea water. It is desirable that the control valves in the underwater Christmas tree be provided With automatic fail-safe hydraulic operators which permit automated control of the well. In both cases, the hydraulic lines to be automated operator may extend two or three miles from a control point. Due to the pressure of wells, it has been customary to use hydraulic operators designed to operate on a pressure of approximately 1000 p.s.i. Inasmuch as there is a large pressure drop in a hydraulic line of considerable length, it has been found necessary to provide a large line to the operator even though a large line is expensive. If a small line is used, line friction will result in a low rate of flow and a large pressure drop, and consequently the initial pressure has to be considerably greater than the pressure required at the operator to obtain a suitable ow rate, then when the hydraulic operator reaches the end of its stroke and no more tluid is required, the initial pressure will be developed which oftentimes is too great for the operator. Also, it is customary to use a single line system and rely on spring pressure to move the valve to the other position. In using long lines it is difficult for the return spring in the operator to develop suilicient pressure to force back the hydraulic iluid in the short time usually desired for the operation of the valve since line friction in the line reduces the speed of movement of the hydraulic iluid. In order to overcome the objections of a small line, and the expense of a large line, the present invention discloses a system which permits the utilization of a single small line without the possibility of overpressurization of the hydraulic operator to be controlled and which permits the utilization of a spring to operate the valve.

In order to accomplish the above, the control system of the present invention is comprised of a hydraulically operated valve requiring a relatively high pressure, for example in the neighborhood of 1000 p.s.i., to operate the valve in one direction and having a spring of sufllcient magnitude to move the valve to the other position upon release of pressure, a single small hydraulic line extending from the operator, a pressure source capable of delivering at the operator a pressure of at least 1000 p.s.i., a pressure regulator in the hydraulic line receiving the pres- 3,252,472 Patented May 24, 1966 Cce sure from the pressure source and transmitting a constant pressure to the hydraulic operator; The pressure regulator has a relief valve to relieve any excess pressure. Also provided is a hydraulic unloading valve between the regulator and the hydraulic operator which receives the pressure from the regulator and transmits it to the operator while the pressure in the line is increased or maintained at the selected operating pressure and which dumps the hydraulic fluid rather than returning it to the pressure source when the pressure in the line is decreased below a preset pressure. By dumping the hydraulic iluid close to the hydraulic operator, it is possible to return the valve to the otherv position in a short period of time Without the utilization of an extremely large and heavy spring.

In attempting to obtain units for the system, no cornmercial pressure regulator which included an internal relief adaptable for high pressure hydraulic service or a hydraulic unloading valve suitable for high pressure hydraulic service could be found. Accordingly, these two units had to be developed in order to permit the construction of the improved control system for automated valve operators.

The improved combined pressure regulator and internal relief valve is suitable for high pressure hydraulic service and permits the utilization of a single small line which has an originating pressure high enough to permit a relatively large pressure drop in the line and yet develop at the inlet of the regulator a pressure in ex-cess of 1000 p.s.i. The regulator transmits a regulated pressure to the operator. When the operator has finished its stroke, the regulator prevents any buildup of excess pressure and retains the required pressure on the operator. Should the regulating valve leak to increase the pressure on the operator, the included pressure relief valve which is set at a pressure approximately p.s.i. above the operating pressure will function to relieve the excess pressure. The valve is simple in construction and inexpensive to manufacture.

The improved hydraulic unloading or dump' valve delivers the pressure received from the pressure regulator to the operator. As long as the pressure is maintained on the inlet side of the dump valve, the fluid pressure is maintained on the operator and the dump port to the sea remains closed. However, as soon as the pressure is lowered beyond a set point for any reason, the discharge valve opens and permits the fluid in the operator to be discharged into the sea. Hydraulic fluid being incompressible, it is necessary to remove only a very small amount of fluid from the line to reduce the pressure thus eliminating the need for back llowing the iluid through the small line. The set dump pressure is still suflicient to prevent any operator piston movement and resulting iluid ffow when the pressure is reduced from the 1000 p.s.i. A novel safety feature of this. valve is that the fluid from the operator can return through the control line should the dump port to the sea become clogged for any reason. As previously mentioned, this would result in a very slow and undesirable Valve operationonly acceptable as an emergency measure. The unloading valve is simple in construction, inexpensive to manufacture and suitable for high pressure hydraulic service.

As can be seen from the above, the principal object of the present invention is to provide an unloading valve for use in a cont-rol system for an automated hydraulic operator which permits the utilization of a single small line.

Another object is to provide a hydraulic unloading valve which will deliver to the operator pressure from the regulator and by merely dropping the line pressure will discharge the hydraulic tluid to permit the valve to move to its other position by the utilization of normal spring pressure.

A further object is to provide a hydraulic unloading valve which has provisions that in the event the discharge port is inoperative lluid may discharge through the inlet port.

A further object is to provide a hydraulic unloading valve equipped with valving which permits pressure buildup without discharging, but on drop of pressure beyond preset point will discharge pressure from the outlet port.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiments about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

Preferred embodiments of the invention have been chosen for purpose of illustration and description and are shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. 1 is a schematic diagram of the control system of the present invention, with the valve being operated in open position.

FIG. 2 is a view similar to FIG. 1 with the valve closed.

FIG. 3 is a cross section of the unloading valve in the position shown in FIG. 1.

FIG. 4 is a view similar to FIG. 3 with the discharge valve open similar to the position in FIG. 2.

For the purpose of illustrating the invention, a hydraulically operated reciprocating gate valve has been chosen since this type is the most commonly used valve for wellhead service, however, any other type of valve capable of being operated by a hydraulic operator may be controlled by the proposed system of this invention.

Referring now to the drawings, there is disclosed a fail safe closed hydraulically operated valve which is controlled by the system of the present invention. The valve 10 is a reciprocating parallel expanding gate valve having a valve member 12 which reciprocates between the open and closed positions and expands in the fully open and fully closed position to form a seal with seats 13. The valve member has a port 14 in the upper portion thereof which in the open position is aligned with the inlet and outlet ports 16 of the valve. Extending from the valve member 12 is a stem 18 which is attached to a piston 20 located in a cylinder 22 of a hydraulic operator 24. Surrounding the cylinder 22 is a spring 26 which is attached to the outer end of the stem 18. Surrounding the spring 26 is a cover 28 which encloses the operator and seals all working parts from the elements. The operator 24 has a base 30 which is provided with a port 32 which leads to the upper side of the cylinder 22. Hydraulic pressure applied to the upper side of the cylinder overcomes the force of the spring 26 and moves the piston 20, stem 18 and valve member 12 axially inward so that the port 14 is aligned with the inlet and outlet ports 16. The valve 10 is then in the open position. Release of the pressure in the upper part of the cylinder 22 permits the spring 26 to extend thereby moving the piston 20, stem 18 and valve member 12 axially outward closing the valve. In addition to the power of the spring 26, the uid owing through the valve will also act on the valve member 12 assisting in moving the valve member 12 axially outward in the valve chamber. Attached to the port 32 in the base 30 of the operator 24 is a small hydraulic line 34. The line 34 extends to a pressure source 36 which is capable of delivering at the operator 24 hydraulic uid having a pressurevof at least sufcient magnitude to operate the valve 10. This pressure may be in the neighborhood of approximately 1000 p.s.i. which has been found to be suflcient in combination with the selected cylinder size to operate the valve against the flow of uids owing through the valve. Located close to the pressure source 36 is a three-way control valve 37 which will direct pressure to the operator 24 or will permit pressure from the operator to be discharged.

Positioned in the hydraulic line 34 near the operator 24 is a pressure regulator 38, which receives pressure from the pressure source 36 and transmits a regulated pressure.

Between the pressure regulator 38 and hydraulic operator 24 there is positioned an unloading valve 76 which receives the pressure from the pressure regulator 38 and transmits it to the hydraulic operator 24 while the pressure in the line 34 is being increased or maintained at the selected operating pressure and which will dump the hydraulic uid from the operator 24 when the pressure in the line 34 is decreased beyond a set pressure, see FIGS. 6 and 7. This permits the spring 26 in the hydraulic operator 24 to move the valve member 12 to the other position in a short period of time since it does not have` to overcome the line friction of the hydraulic Huid moving in a small line.

The unloading valve 76 is formed of a housing 78 having an inlet port 80 which receives the hydraulic line 34 coming from the outlet port 62 of the pressure regulator 38. In communication with the inlet port 80 is a cylindrical chamber 82 in which is positioned a piston 84 which is provided with a circumferential seal 86 sealing the inlet port 80 from the cylindrical chamber 82. The piston also has a second circumferential seal 88 which seals the cylindrical chamber from the remaining portion of the housing. The piston 84 has a central passage 90 at the inlet port end in which is located a poppet valve member 92. The piston has a second central passage 94 in which is located a stem 96. A seal 98 is provided around the stem to prevent leakage of fluid into the remaining parts of the housing. The poppet valve member 92 has an extension 100 which can be contacted by the stem to move the poppet valve member 92 from its seat. As previously mentioned, poppet valves have been found desirable; however, other types of valves known in the art to seal a passage may Ibe used. The housing has an outlet port 102 which communicates ywith the cylindrical chamber 82 `but is sealed by the circumferential seal 86 from the inlet port 80. The housing also has a second port 104 which is also in communication with the cylindrical chamber 82 and is likewise sealed from the inlet port 80 by the circumferential seal 86. The piston 84 has transverse passages 106 which communicate with the cylindrical chamber 82 adjacent the outlet passage 102 and the second port 104. Therefore, when the poppet valve 92 is opened, there will be tlow from the inlet port 80 through the central passage 90 and out through the ports 102-104, see FIG. 6. Surrounding the stem 96 is a spring 108 which bears against the end of the piston 84 through a spring plate 110. The other end of the spring 108 bears against a portion 112-of the housing 78. As'shown in the drawing, portion 112 of the housing is threaded into the other portion of the housing and pressure adjusting shims 114 may be positioned between the end of the spring and the portion 112 of the housing. Also located around the stem 96 is a piston stop 116 which permits a predetermined amount of piston movement. The unloading valve is also provided with a discharge passage 118 in which is positioned a poppet valve 120 which is held in its seat by a light spring 122. A collar 124 is positioned around the end of the stem and contacts an extension 126-of the poppet valve to move it off its seat in operating condition. The arrangement is such that when the pressure at the inlet port 80 is not suicient to overcome the action of the spring 108 the piston 84 will move toward the inlet end of the housing and the collar 124 will 4bear against the extension 126 of the poppet discharge valve 120 moving it off its seat opening the discharge valve 120, see FIG. 7. The housing 78 is provided with a passage 128 which communicates with the discharge passage 118. A line 130 connects the second passage 104 with the passage 128 whereby, when the valve 92 is closed, flow 'from the outlet port 102 will tiow through the second port 104 through the line 130 and out through the discharge passage 118 and through check valve 132 to the atmosphere or sea. The check valve 132 prevents vback ow. This will quickly discharge any fluid in the hydraulic operator 24 permitting the spring 26 to swiftly move the piston 20 to the other end of the operator thereby operating the valve within the required period of time. If for some reason the discharge passage 118 is blocked, the flow from the operator will flow through the outlet port 102 and will unseat the poppet valve 92 and will 'be permitted to flow back through the inlet passage to the pressure vsource and thereby the valve Will operate, however, at a much slower rate because of the line friction restraining the return llow of the hydraulic fluid.

Both the pressure regulator 38 and the unloading valve 76 are so designed that they may lbe vented to atmosphere, sea water or if desired enclosed in a canister with the Wellhead and operated against the pressure contained in the wellhead canister. The vent 136 of the regulator 38 may contain a check valve or be connected to a pressure source within a wellhead canister. In the line between the pressure regulator 38 and hydraulic operator 24 is the unloading valve 76 which has two primary functions. One,A during pressure buildup and operation, the unloading valve 76 receives theV pressure from the regulator 38 and transmits it to the hydraulic operator 24, see FIG. 1. Second, upon decrease of pressure beyond a set point, the discharge valve 120 is opened dumping the hydraulic lluid in the operator 24, see FIG. 2. Since hydraulic fluid is in effect incompressible, the relieving of a very small amount'of fluid, by moving the 3-way control valve 37 to discharge, will relieve the pressure in the unloading valve 76 which will close the valve 92 allowing the spring 108 to return the piston 34 and open the discharge valve 120 which will dump the hydraulic fluid in the operator 24 expeditiously. Such action permits fast action of the valve by the spring 26. If the hydraulic iluid in the cylinder 22 is not dumped close tothe operator 24, there will be a lag in operation as the line function of the fluid returning in the long line will substantially retard movement of the piston 20. However, as a safety feature the unloading valve 76 isv so designed that if the discharge passage 118 is blocked or the discharge valve 120 becomes inoperative, the valve 92 is unseated and the hydraulic fluid can flow back to th-e pressure source 36 where it can be discharged. As mentioned, this would drastically lengthen the time required for operation of the valve 10 and is only to 'be considered as an emergency means. As with the pressure regulator 38, the unloading Valve 76J is provided with means to permit adjustment of pressures and venting.

The control system of the present invention provides a means of facilitating operation of remotely located hydralically operated valves permitting use of an inexpensive small single control line yet at the same time insuring that the operator receives only the required pressure and assure fast return operation *by dumping the hydraulic fluid in the operator near the operator eliminating time lag due to line friction.

As various changes may be made in the form, construction and arrangements of the parts herein without. departing from the spirit and scope of the invention and without sacricing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. For a system having a hydraulically operated valve having a piston operator requiring the application of pressure on one side of the piston and a spring `on the other side of the piston which will move the valve to the other position on the release of pressure, operated by the pressure from` a small single hydraulic line extending some length from the valve, an unloading valve, said valve comprising: a housing having-an inlet port, a cylindrical chamber in communication with said inlet port, a piston in said cylindrical chamber having circumferential seals with the Wall of the cylindrical chamber; a central passage in the inlet port end of said piston,

a valve member in said passage, a second central passage in the other end of said piston, a stem through said second centr-al passage disposed in the housing and adapted to contact the valve member to move the valve from its seat upon movement of the piston away from the inlet end of the housing, an outlet port in the housing communicating with the cylindrical chamber but sealed from the inlet port by the circumferential seal of the piston, a plurality of transverse passages in the piston communicating with the cylindrical chamber adjacent the outlet port, the transverse passages in the piston being in communication with the central passage in the inlet end of the piston so that when the valve in the central p-assage is open ow from the inlet port will flow through the central passage and out the outlet port; a spring having one end bearing against the other end of the piston, a stop in the housing for the other end of the spring, a discharge passage in the housing located at the end of the housing opposite the part having the piston chamber, a line communicating said discharge passage with the outlet port, a valve in said discharge passage having yan operating extension, said stenl cooperating with the piston and contacting the extension of the valve in the discharge passage, the construction and -arrangement being such that when the pressure at the inlet end is not sufiicient to overcome the spring the piston will move the stem to cause the operating extension to open the discharge valve whereby ow from the outlet passage will flow through the discharge passage.

2. An unloading valve for a control system for a hydraulically operated valve, said unloadingvalve comprising: a housing having an inlet port, a cylindrical chamber in communication with said inlet port, a piston in said cylindrical chamber having circumferential seals with thewall of the cylindrical chamber; a central passage in the inlet port end of said piston, a poppet valve member in said passage, a second central passage in the other end of said piston, a stern in said second passage, the valve member having an extension which can be contacted by the stem to move the valve from its seat upon movement of the piston away from the inlet end of the housing, an outlet port in the housing communicating with the cylindrical chamber but se-aled from the inlet port by the circumferential seal of the piston, a second port in the housing communicating with the cylindrical chamber but sealed from the inlet port by the circumferential seal of the piston, a plurality of transverse passages in the piston communicating with the cylindrical chamber adjacent the' outlet port and the second port, the transverse passages in the piston being in communication with the central passage in the inlet end of the piston so that when the valve in the central passage is open flow from the inlet port Will flow through the central pass-age and out the outlet port and the second port; a spring surrounding the stem and having one end bearing against the end of the piston, a stop in -the housing for the other end of the spring, a discharge passage in the housing at the end of the housing opposite the piston chamber, a valve in said discharge passage having an operating extension, a portion on the end of the stem contacting the operating extension of the valve in the discharge passage, the construction and arrangement being such that Awhen the pressure at the inlet end is not suflicient to overcome the spring the piston will move the stem to cause the extension to open the discharge valve, a passage in the housing communicating with the discharge passage, a line connecting the second port and the passage in the housing communicating with the discharge passage whereby when the piston valve is closed flow from the outlet passage will flow through the second port, through the line and out the discharge passage,

3. An unloading valve for a control system for a hydraulically operated valve, said unloading -valve cornprising: -a housing having an' inlet port, a cylindrical chamber in communication with said inlet port, a piston in said cylindrical chamber having circumferential seals with the wall of the cylindrical chamber; a central passage in inlet port end of said piston, a valve member in said passage, a second central passage in the other end of said piston, a stem in said second passage, means by which the valve member can be contacted by the stem to move the valve from its seat upon movement of the piston away from the inlet end of the housing, an outlet port in the housing communicating with the cylindrical chamber but sealed from the inlet port by the circumferential seal of the piston, a plurality of transverse passages in the piston communicating with the cylindrical chamber adjacent the outlet port, the transverse passages in the piston being in communication with the central passage in the inlet end of the piston so that when the valve in lthe central passage is open flow from the inlet port will ow through the central passage and out the outlet port; a spring surrounding the stem and having one end bearing against the end of the piston, a stop in the housing for the other end of the spring, a discharge passage in the housing at the end of the housing opposite the piston chamber, a line communicating said discharge passage with the outlet port, a valve in said discharge passage having an operating extension, a portion on the end of the stem contacting the operating extension of the v-alve in the discharge passage, the construction and arrangement being such that when the pressure at the inlet end is not sucient to overcome the spring, the piston will move the stem to cause the operating extension to open the discharge valve whereby when the piston valve is closed ow from the outlet passage will ow through the discharge passage.

4. An unloading valve for a control system for a hydraulically operated valve, said unloading valve cornprising: a housing having an inlet port, a cylindrical chamber in communication with said inlet port, a piston in said cylindrical chamber having circumferential seals with the wall of the cylindrical chamber; a central passage in inlet port end of said piston, a valve member in said passage, a second central passage in the other end of said piston, a stem movably extending through said second central passage and adapted to contact said valve to move the valve from its seat upon movement of the piston away from the inlet end of the housing, an outlet port in the housing communicating with the cylindrical chamber but sealed from the inlet port by the circumferential seal of the piston, a plurality of transverse passages in the piston communicating with the cylindrical chamber adjacent the outlet port, the transverse passages in the piston being in communication with the central passage in the inlet end of the piston so that when the valve in the central passage is open flow from the inlet port will flow through the central passage and out the outlet port; a spring having one end bearing against the end of the piston opposite said inlet port end, a stop in the housing for the other end of the spring, a discharge passage in the housing at the end of the housing opposite the piston chamber, a line communicating said discharge pass-age with the outlet port, a valve in said discharge passage having an operating extension, said stern cooperating with the piston and adapted to contact the operating extension of the valve in the discharge passage, the construction and arrangement being such that when the pressure at the inlet end is not sufcient to overcome the spring the piston will move the stern to cause the operating extension to open the discharge valve whereby flow from the outlet passage will flow through the discharge passage.

5. An unloading valve for a control system for a hydraulically operated valve, said unloading valve comprising: a housing having an inlet port, a chamber in communication with said inlet port, a piston in said chamber having a peripheral seal with the wall of the chamber; a passage in the inlet port end of said piston, a valve member in said passage, a second passage in the other end of said piston, means passing through said second passage by Which the valve member can be contacted to move the valve from its seat upon movement of the piston away from the inlet end, an outlet port in the housing communicating with the chamber but sealed from the inlet port by the peripheral seal of the piston, a second port in the housing communicating with the charnber but sealed from the inlet port by the peripheral seal of the piston, passages in the piston communicating with the cylindrical chamber adjacent the outlet port and the second port, the passages being in communication with the passage in the inlet end of the piston, so that when the valve in the passage of the inlet end is open tiow from the inlet port will ow through the passage and out the outlet port and second port; a spring bearing against the piston of sucient strength whereby upon a decrease in pressure on the inlet side of the piston the piston will move toward the inlet end of the valve with the means operating the valve in the inlet end of the piston becoming disengaged from the valve and closing it, a discharge passage in the housing at the end of the housing opposite the piston chamber, a valve in said discharge passage, means operably associated with said means passing through the second passage for opening the discharge Valve when pressure in `the inlet is insufficient to overcome the spring, a passage in the housing communicating with the discharge passage, a line connecting the second port and the passage in the housing communicating with the discharge passage whereby when the piston valve is closed ow from the outlet passage will ow through the second port, through the line and out the discharge outlet.

References Cited by the Examiner UNITED STATES PATENTS 2,969,806 l/l96l Jensen 137-107 X 3,002,520 10/1961 Morse 137-102 FOREIGN PATENTS 707,165 3/1954 Great Britain.

[SADOR WEIL, Primary Examiner.

WILLIAM F. ODEA, Examiner.

I. ONEILL, A. COI-IAN, Assistant Examiners.

Claims (1)

1. 5. AN UNLOADING VALVE FOR A CONTROL SYSTEM FOR A HYDRAULICALLY OPERATED VALVE, SAID UNLOADING VALVE COMPRISING: A HOUSING HAVING AN INLET PORT, A CHAMBER IN COMMUNICATION WITH SAID INLET PORT, A PISTON IN SAID CHAMBER HAVING A PERIPHERAL SEAL WITH THE WALL OF THE CHAMBER; A PASSAGE IN THE INLET PORT END OF SAID PISTON, A VALVE MEMBER IN SAID PASSAGE, A SECOND PASSAGE IN THE OTHER END OF SAID PISTON, MEANS PASSING THROUGH SAID SECOND PASSAGE BY WHICH THE VALVE MEMBER CAN BE CONTACTED TO MOVE THE VALVE FROM ITS SEAT UPON MOVEMENT OF THE PISTON AWAY FROM THE INLET END, AND OUTLET PORT IN THE HOUSING COMMUNICATING WITH THE CHAMBER BUT SEALED FROM THE INLET PORT BY THE PERIPHERAL SEAL OF THE PISTON, A SECOND PORT IN THE HOUSING COMMUNICATING WITH THE CHAMBER BUT SEALED FROM THE INLET PORT BY THE PERIPHERAL SEAL OF THE PISTON, PASSAGES IN THE PISTON COMMUNICATING WITH THE CYLINDRICAL CHAMBER ADJACENT THE OUTLET PORT AND THE SECOND PORT, THE PASSAGES BEING IN COMMUNICATION WITH THE PASSAGE IN THE INLET END OF THE PISTON, SO THAT WHEN THE VALVE IN THE PASSAGE OF THE INLET END IS OPEN FLOW FROM THE INLET PORT WILL FLOW THROUGH THE PASSAGE AND OUT-

Images