A hydraulic drive mechanism for a plug valve

Abstract

An economical and practical plug valve hydraulic drive mechanism is composed of a cylinder valve cover, a hydraulic cylinder barrel, a piston, a cylinder cover, an indicator rod, a pressure plate, an oil pipe joint, a valve stem, a thrust bearing, a cover flange and matching seals and connectors: a valve stem, two thrust bearings and a cover flange are installed at the center and lower end of the cylinder valve cover; in the hydraulic cylinder barrel, the insertion ends of the cylinder valve cover and the cylinder cover respectively cover the rectangular spline columns at both ends of the piston with rectangular spline holes; the lower end of the piston covers the spiral spline column at the upper end of the valve stem with a spiral spline hole; the upper end of the piston fixes the lower end of the indicator rod with a pressure plate and a countersunk screw; the two ends of the hydraulic cylinder barrel are connected to the cylinder valve cover and the cylinder cover with cylindrical head screws to form a whole; the upper end of the indicator rod and the lower end of the valve stem extend out of the upper end surface of the cylinder cover and the lower end surface of the cylinder valve cover and the cover flange respectively. It has a compact structure, is accurate and reliable, and is inexpensive, and is particularly suitable for remote automatic control of high-pressure, large-diameter plug valves.

Description

Technical Field

[0001] The invention relates to hydraulic drive of a high-pressure and large-diameter plug valve in the petroleum machinery and valve industries. Background Art

[0002] The high-pressure, large-diameter plug valve has a large switching resistance. When operated manually, the crowbar used is long, the movement range is large, and the operation is laborious. Therefore, the hydraulic drive of this type of plug valve can not only reduce the labor intensity of the operator, but also realize the automation of equipment control and adapt to the general trend of social development. In addition, it may also prevent personal safety accidents in situations where there are toxic or dangerous pressure media. However, the current high-pressure, large-diameter plug valves are rarely hydraulically driven due to factors such as cost and price. Second, some of them use traditional hydraulic cylinders to drive rack gears or rocker drive mechanisms, which have problems such as large size, loose structure, poor force, and easy damage. Third, the "spiral hydraulic swing cylinder" currently produced and sold professionally in the domestic and foreign markets can also be used to drive high-pressure, large-diameter plug valves, but its structure is complex, difficult to process, and expensive. The price of its drive mechanism is even higher than that of the plug valve body, which is unacceptable. Therefore, it is necessary to develop a hydraulic drive mechanism for high-pressure, large-diameter plug valves that is inexpensive and good quality. Summary of the invention

[0003] The present invention mainly aims at the problems of the existing "spiral hydraulic swing cylinder" such as complex structure, difficult processing and high price, and makes an innovative design to provide an economical and practical special hydraulic driving mechanism for a plug valve.

[0004] The present invention is composed of a cylinder valve cover, a hydraulic cylinder barrel, a piston, a cylinder cover, an indicating rod, a pressure plate, an oil pipe joint, a valve stem, a thrust bearing, a cover flange and matching sealing members and connecting members. The unique features of the present invention are as follows: a valve stem, two thrust bearings and a cover flange are installed at the center and the lower end of the cylinder valve cover; in the hydraulic cylinder barrel, the insertion ends of the cylinder valve cover and the cylinder cover respectively cover the rectangular spline columns at both ends of the piston with rectangular spline holes; the lower end of the piston covers the spiral spline columns at the upper end of the valve stem with spiral spline holes; the upper end of the piston fixes the lower end of the indicating rod with a pressure plate and a countersunk screw; the two ends of the hydraulic cylinder barrel are connected to the cylinder valve cover and the cylinder cover with cylindrical head screws to form a whole; the upper end of the indicating rod and the lower end of the valve stem respectively extend out of the upper end surface of the cylinder cover and the lower end surfaces of the cylinder valve cover and the cover flange.

[0005] Since the present invention combines the lower cylinder cover of the hydraulic cylinder and the valve cover of the plug valve into one, and installs the valve stem, thrust bearing, cover flange and matching sealing ring in the center hole thereof, the problem of repeated configuration of the thrust bearing, sealing ring, lower cylinder cover and valve cover when using an external "spiral hydraulic swing cylinder" is avoided, thereby simplifying the product structure, reducing the product volume and lowering the cost price. The inner end of the cylinder valve cover and the cylinder head adopts a rectangular spline hole to cooperate with the rectangular spline column at both ends of the piston to prevent rotation, which has a compact structure and is easy to process; the lower end of the piston uses a spiral spline hole to directly drive the spiral spline column at the upper end of the valve stem to rotate, avoiding the repeated configuration of rotating parts when using an external "spiral hydraulic swing cylinder", which is more conducive to reducing the product volume and reducing the cost price; the longer spiral spline column at the upper end of the valve stem and the piston stroke can convert most of the piston's thrust into the rotation force of the valve stem; the fixed piston stroke and valve stem spiral angle can accurately control the plug valve to rotate 90° for opening and closing without other limit parts; the rectangular splines and spiral splines at both ends of the piston are all immersed in hydraulic oil, which can be fully lubricated, reduce the friction resistance between parts, and extend its service life. The upper end of the indicator rod extends out of the upper end face of the cylinder cover to display the opening and closing status of the valve; the lower end of the valve stem extends out of the lower end face of the cylinder valve cover and the cover flange to transmit the driving force of the piston to the plug in the valve body. Therefore, the present invention has the characteristics of compact structure, easy processing, precision and reliability, low price, etc., and is particularly suitable for remote automatic control of high-pressure and large-diameter plug valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic cross-sectional view of the overall structure of the present invention;

[0007] Figure 2 For the present invention Figure 1 Schematic top view of the AA cross section.

[0008] The names of the parts indicated by the numbers in the figure are as follows:

[0009] 1. Cylinder valve cover, 2. Hydraulic cylinder, 3. Piston, 4. Cylinder head, 5. Cylindrical head screw, 6. Indicator rod, 7. Small sealing ring, 8. Pressure plate, 9. Countersunk screw, 10. Oil pipe joint, 11. Large sealing ring, 12. Valve stem, 13. Sealing ring, 14. Thrust bearing, 15. Copper gasket, 16. Cover flange. DETAILED DESCRIPTION

[0010] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0011] Figure 1 , Figure 2In the figure: the cylinder valve cover 1, the hydraulic cylinder barrel 2, the piston 3, the cylinder cover 4, the indicator rod 6, the pressure plate 8, the oil pipe joint 10, the valve stem 12, the thrust bearing 14, and the cover flange 16 are the main parts of the present invention, the small sealing ring 7, the large sealing ring 11, the sealing ring 13 and the copper gasket 15 are matching sealing parts, and the cylindrical head screw 5 and the countersunk screw 9 are connecting parts of the national standard.

[0012] The cylinder valve cover 1 is a part that has the dual functions of the lower cylinder cover of the hydraulic cylinder and the valve cover of the plug valve. On its large-diameter flange plane, two circles of evenly distributed through holes and a gasket groove are processed. The evenly distributed through holes on the outer circle are large-diameter bolt holes for connecting with the valve body of the plug valve; the evenly distributed through holes on the inner circle are step holes for installing cylindrical head screws 5, which are connected with the lower end of the hydraulic cylinder barrel 2; a gasket groove with an opening downward is used for sealing between the plug valve body; according to the specific requirements of the plug valve, the flange can also be processed with grease injection holes between the evenly distributed through holes, and other parts such as grease injection valves can be installed. The cylinder valve cover 1 is bounded by its large diameter flange, with a longer hollow cylindrical insertion end at the top and a shorter hollow cylindrical protruding end at the bottom; three grooves are cut on the cylindrical surface of the upper insertion end for installing a large sealing ring 11; at the center of the insertion end, the upper end is a rectangular spline hole, and below the rectangular spline hole is a longer cylindrical hole with an increased diameter that can be used as a back-off groove to provide space for the piston 3 to move. On the end surface of the lower protruding end, there are several threaded blind holes evenly distributed; at the center of the protruding end and the large diameter flange is a stepped through hole, and two sealing grooves are cut on the hole wall of the stepped hole with a smaller diameter, so that the valve stem 12, the sealing ring 13, the two thrust bearings 14, the copper gasket 15 and the cover flange 16 can be connected into one by a cylindrical head screw 5.

[0013] The hydraulic cylinder 2 is a hollow cylindrical part, and on the annular planes at both ends thereof, there are evenly distributed several threaded blind holes for external connection; on the circumferential surface of the cylinder, there are symmetrically distributed two reducing through holes with threads at the inlet for connecting the oil pipe joint 10.

[0014] Above the cylinder head 4 is a flange with several stepped holes evenly distributed. The center of the flange has a round boss and a through hole, and two grooves for installing small sealing rings 7 are cut in the through hole; below the flange is a longer hollow cylindrical insertion end, and three grooves for installing large sealing rings 11 are cut on the surface of the cylinder at the insertion end; at the center of the insertion end, the lower end is a rectangular spline hole, and above the rectangular spline hole is a longer cylindrical hole with an increased diameter that can be used as a backing groove, which also serves as the activity space of the piston 3.

[0015] The middle of the piston 3 is a flat cylinder with a relatively large diameter. Two grooves for installing large sealing rings 11 are cut on the circumference of the flat cylinder to precisely contact the inner wall of the hydraulic cylinder 2. At both ends of the flat cylinder, there are symmetrically distributed backsliding grooves and longer rectangular spline columns. The length of the rectangular spline columns must be guaranteed to be within the stroke range of the piston 3. The spline columns at both ends can be connected with the rectangular spline holes at the insertion ends of the cylinder valve cover 1 and the cylinder cover 4 respectively. At the center of the upper end of the piston 3, there are step holes and evenly distributed small threaded blind holes for fixing the indicator rod 6, the pressure plate 8 and the countersunk screw 9; at the center of the lower end of the piston 3, there are spiral spline holes and longer cylindrical holes with increased diameter that can be used as backsliding grooves to connect the spiral spline columns of the valve stem 12.

[0016] The valve stem 12 is a columnar part, and above it is a long spiral spline column, the length of which must ensure that when the piston 3 stops at the upper end of the stroke, the spiral spline hole at the lower end of the piston 3 is also completely connected with the spiral spline column above the valve stem 12; below the spiral spline column is a smooth cylinder, below the smooth cylinder is a raised shoulder, below the shoulder is also a smooth cylinder, and the lower end of the smooth cylinder is machined with a through-length flat key; the cylinder and the spiral spline column above and below the shoulder have the same diameter to facilitate the installation of the thrust bearing 14, and are sealed with the sealing ring 13 in the center hole of the cylinder valve cover 1 and the cover flange 16.

[0017] The indicator rod 6, the pressure plate 8, the oil pipe joint 10, the thrust bearing 14 and the cover flange 16 are either conventional parts with simple structures or universal parts and standard parts; the cover flange 16 is used to support and seal the valve stem 12 and the thrust bearing 14, and to withstand the axial force generated by them.

[0018] When the present invention is used, a sealing gasket and a large bolt are installed on the valve body of the plug valve through the uniformly distributed holes on the outer ring of the cylinder valve cover 1 and the gasket groove below. The full-length flat key at the lower end of the valve stem 12 is connected with the keyway on the plug in the valve. Hydraulic oil is input into the hydraulic cylinder 2 through the oil pipe joint 10, and the piston 3 is driven to make reciprocating axial motion in the center hole of the insertion end of the hydraulic cylinder 2, the cylinder valve cover 1 and the cylinder cover 4. The lower end of the piston 3 drives the valve stem 12 to reciprocate at an angle of 90 degrees through the spiral spline to drive the switch of the plug valve.

Claims

1. A plug valve hydraulic drive mechanism, consisting of a cylinder valve cover, a hydraulic cylinder barrel, a piston, a cylinder cover, an indicator rod, a pressure plate, a tubing joint, a valve stem, a thrust bearing, a cover flange and matching seals and connectors, and is characterized by: The valve stem, two thrust bearings and the cover flange are installed at the center and the lower end of the cylinder valve cover; in the hydraulic cylinder, the insertion end of the cylinder valve cover and the cylinder cover respectively covers the rectangular spline columns at both ends of the piston with rectangular spline holes; the lower end of the piston covers the spiral spline column at the upper end of the valve stem with a spiral spline hole; the upper end of the piston fixes the lower end of the indicator rod with a pressure plate and a countersunk screw; the two ends of the hydraulic cylinder are connected to the cylinder valve cover and the cylinder cover with cylindrical head screws to form a whole; the upper end of the indicator rod and the lower end of the valve stem extend out of the upper end surface of the cylinder cover and the lower end surface of the cylinder valve cover and the cover flange respectively; The middle of the piston is a flat cylinder with a relatively large diameter. Two grooves for installing large sealing rings are cut on the circumference of the flat cylinder. At both ends of the flat cylinder, there are symmetrically distributed backhoe grooves and longer rectangular spline columns. At the center of the upper end of the piston, there are step holes and evenly distributed small threaded blind holes for fixing the indicator rod, pressure plate and countersunk screws. At the center of the lower end of the piston, there are spiral spline holes and longer cylindrical holes with increased diameter that can be used as backhoe grooves. The valve stem is a cylindrical part, with a long spiral spline column on the top, a smooth cylinder below the spiral spline column, a raised shoulder below the smooth cylinder, and a smooth cylinder below the shoulder. A full-length flat key is processed at the lower end of the smooth cylinder; the diameters of the cylinder and the spiral spline column above and below the shoulder are the same; The cylinder valve cover is bounded by its large diameter flange, with a longer hollow cylindrical insertion end on the top and a shorter hollow cylindrical protruding end on the bottom; three grooves for installing large sealing rings are cut on the cylindrical surface of the upper insertion end; in the center of the insertion end, the upper end is a rectangular spline hole, and below the rectangular spline hole is a longer cylindrical hole with an increased diameter that can be used as a back-off groove; on the end surface of the lower protruding end, there are several threaded blind holes evenly distributed; in the center of the protruding end and the large diameter flange is a step through hole, and two sealing grooves are cut on the hole wall of the smaller diameter step hole; The cylinder valve cover is installed on the valve body of the plug valve with a sealing gasket and a large bolt through the evenly distributed holes on the outer ring and the gasket groove below. The full-length flat key at the lower end of the valve stem is connected with the keyway on the plug in the valve. Hydraulic oil is input into the hydraulic cylinder through the oil pipe joint, driving the piston to make reciprocating axial motion in the center hole of the hydraulic cylinder, the cylinder valve cover and the insertion end of the cylinder cover. The lower end of the piston drives the valve stem to make a 90° reciprocating rotation through the spiral spline to drive the plug valve to open and close.

2. The plug valve hydraulic drive mechanism according to claim 1 is characterized in that: Above the cylinder head is a flange with several step holes evenly distributed. In the center of the flange there is a round boss and a through hole with two grooves cut in the through hole for installing small sealing rings. Below the flange is a longer hollow cylindrical insertion end with three grooves cut on the surface of the cylinder for installing large sealing rings. In the center of the insertion end, at the lower end is a rectangular spline hole, and above the rectangular spline hole is a longer cylindrical hole with an increased diameter that can be used as a back-off groove.

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