RU2521701C1 - Ball valve - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: ball valve comprises a casing with an inlet hole and an outlet hole and a supporting surface on its lower part, a seat with conical sealing surface, a part taken-out from a globe valve with spherical surface, a lamp with a gland, a drive with reciprocating rod and a device to provide for the interaction of the sealing surfaces of the globe valve and the casing seat. The casing is equipped by the second seat set opposite to the first seat. The globe valve is made from two movable segments with disks. Sealing surfaces are provided on the disk. The movable segments are interconnected pivotally via an axis set in the casing supporting surface. In the upper part each segment is connected pivotally to the lower end of the rod through the introduced levers with axes. The said introduced device consists of a nut with nonlocking thread which is rigidly fixed in the drive slider and interacts with the respective rod thread, and a set of disk springs set with preload in the lamp casing.EFFECT: improved leakproofness of a globe valve and, on the whole, longer service life of fittings at the operation in main pipelines with large diameters and flows of working medium with abrasive inclusions and low drive forces.9 cl, 3 dwg

Description

The invention relates to pipe fittings and is intended to control the flow of a working medium in high pressure pipelines at high flow rates of a working medium containing impurities with abrasive inclusions, and can also be widely used in technological processes of petrochemical processing with temperatures up to 500 ° C.

Known designs of a single-seat segment rotary valve (Bragin B.F. Pipe fittings for abrasive hydraulic mixtures. M .: Mechanical Engineering, 1981, Fig. 22, 25), containing a housing with inlet and outlet openings, a tapered valve seat and a locking element made in the form segment with a spherical sealing surface.

The disadvantage of these valves is the constant contact between the sealing surfaces in the process of their mutual movement, which entails their strong wear when abrasive particles get between the rubbing surfaces.

This circumstance complicates the use of these valves in main pipelines, where the working medium is oil or gas containing minor impurities with abrasive inclusions.

There is a design of a ball valve with movable seats, where the ball valve rotates in two axes by 90 °, and the movable saddles provide compression and squeezing of the sealing conical surfaces, providing sealing of the valve in the closed position and clearance when the valve is rotated, protecting the sealing surfaces from wear in an abrasive medium . The saddle control system is technically quite complicated, especially if the valve works at high temperatures of the working medium (patent No. 2355933, publ. 05.20.2009).

The closest technical solution taken as a prototype is the construction of a Cameron ball valve ORBIT (website http://www.cam.com/Forms/Resource.aspx?ResourceID=al 83a4fe-b027-4941-912b-cf0799f6flb2 p. 5 )

The design of the ball valve comprises a housing with an inlet and an outlet and a supporting surface made in its lower part, a seat with a conical sealing surface, a removable part consisting of a ball valve with a spherical surface, a lamp with an oil seal, an actuator with a reciprocating rod, a device leading to the interaction of the sealing surfaces of the ball valve and the housing seat.

To close the crane, along the rotation of the handwheel, the rod begins to lower, while the spiral grooves in the rod interact with the fixed guide fingers, causing the rotation of the rod and the ball. Further rotation of the steering wheel rotates the ball and stem 90 °, while the sealing surface of the ball does not touch the seat. At the last turns of the helm, the spiral grooves change into grooves parallel to the axis of the stem. The latter in the lower position tightly presses the ball to the saddle with a wedge surface. When the valve opens with a similar wedge surface, the stem presses the valve away from the seat, creating a gap between the sealing surfaces. The lack of friction of the sealing surfaces of the shutter during both opening and closing allows the crane to work with contaminated working fluids, including at high temperatures up to plus 427 ° C, providing high tightness of the sealing surfaces and its wear resistance. However, this design does not exclude the following disadvantages.

1. When the ball valve is turned to close and open at a high speed of the working medium, high contact stresses arise between the surface of the spiral grooves and the guide fingers, which leads to increased wear of the rubbing surfaces.

2. When preloading and depressing the ball valve between the rubbing wedge surfaces, high contact stresses arise, which also negatively affect the performance.

All this ultimately affects the reduction of the resource of work. The practical application of the ORBIT brand crane proves the validity of these findings. Due to these shortcomings, the valves have to be repaired often, especially if the working medium contains abrasive components.

3. The one-way seal design of the shutter limits the use of the ORBIT crane on oil and gas pipelines, where a two-way seal is required in emergency situations.

It should be noted that the developers of the ORBIT brand crane declare that the crane is sealed in any direction of flow of the working medium. However, the conclusion is somewhat inaccurate, since the forces from the differential pressure of the working medium acting on the valve with one seat will differ significantly depending on the direction of flow.

Today, valve customers are paying increased attention to the process of choosing the right valve in order to reduce additional production costs and maintenance costs, and in some cases environmental impacts.

Shut-off valves "at the entrance" and "at the exit" are required more and more often. For this purpose, reinforcement with the function of bilateral cut-off and controlled leakage is being developed. Typically, this function can only be performed using two shut-off valves with an intermediate drain valve. This is especially true when the valves operate on a contaminated environment, and the requirements for tightness of the shut-off section of the pipeline are high (class A).

The objective of the invention is to expand the functionality of the valve operating on contaminated media, increase the tightness of the valve and increase the resource of the valve as a whole.

The technical result from the use of the invention lies in the possibility of using it on trunk pipelines of large DN and PN with low drive forces and work on contaminated media with increasing shutter tightness and increasing valve life in general.

The technical result is achieved due to the fact that the ball valve, comprising a housing with an inlet and an outlet and a supporting surface made in its lower part, a seat with a conical sealing surface, a withdrawal part consisting of a ball valve with a spherical surface, a lamp with an oil seal, a drive with the reciprocating movement of the rod, a device leading to the interaction of the sealing surfaces of the ball valve and the seat of the housing, according to the invention, the housing is equipped with a second seat located for example Having cast off the first saddle, the ball valve is made of two movable segments with discs on which sealing surfaces are made, movable segments are pivotally interconnected via an axis installed in the supporting surface of the housing, and in the upper part, each segment is pivotally connected to the lower one through the introduced levers with axes the end of the rod, which, after turning and combining the sealing surfaces of the ball valve, ensures the compression of the sealing surfaces during its further translational movement, a device that converts the translational movement of the rod with the bolt into a rotary one consists of a nut with a non-braking thread installed motionlessly in the inserted drive slider and interacting with the corresponding rod thread, and further translational movement of the rod is provided by the inserted supporting parts of the device that transmit force from the rod to the disk spring package installed with preliminary preload in the lamp housing.

The supporting parts of the device can be located coaxially relative to the rod and consist of two half rings installed in the annular groove of the rod, two rings holding the half rings, two thrust bearings perceiving the rotation of the rod, and two rings centering the thrust bearings.

The optimal location of the sealing surfaces of the shutter with seats after rotation can be fixed by turning the actuator housing relative to the lamp housing due to the inserted flange.

The supporting surface of the housing can be made in the form of a nut with the ability to adjust and fix it relative to the housing.

To adjust the stroke of the rod to open the shutter, a locking nut located in the actuator housing can be inserted.

To control the position of the valve shutter on the rod perpendicular to the axis of the latter can be installed pointer.

At the end of the stem, a coupling can be fixedly mounted that transmits torque when the shutter is turned.

The sealing surfaces of the shutter can be made on hermetically mounted removable disks and serve simultaneously as compensators to ensure synchronous preloading of the sealing surfaces of the shutter.

The discharge of the shutter in any direction of the working medium can be achieved by introducing a bypass line having a shut-off valve at the outlet of the internal cavity of the crane and two check valves, each installed on the line of the inlet and outlet of the crane, and connecting the internal cavity of the crane with the outlet.

Figure 1 shows a longitudinal section of a crane in the "open" position.

Figure 2 shows a longitudinal section of the crane in the closed position.

Figure 3 shows a ball valve with the discharge of the shutter bypass line.

The crane contains a cast body 1 with two welded seats 2 with sealing surfaces from corrosion and carbide surfacing. The inlet and outlet pipes 3 are made for welding with a pipeline. The upper flange 4 and the lower flange 5 of the housing 1 allows you to remove the removable part of the crane during repair without dismantling the housing from the pipeline. The extraction part consists of a ball valve, consisting of two movable segments 6 and 7 and removable disks 8 and 9 with sealing spherical surfaces, fixedly and hermetically fixed to segments 6 and 7. In the lower part of the valve, segments 6 and 7 are pivotally connected through axis 10. The axis 10 is mounted on a fixed adjustable threaded support 12 with a nut 11. The support 12 is made in the form of a nut with an external thread for connection with the housing 1. The support 12 is fixed with the housing 1 by a screw 13. In the upper part of the shutter segments 6 and 7 are pivotally connected to the end the rod 16 through the levers 14 and 15. The shutter is rotated 90 ° with the help of the coupling 17, which is fixedly mounted on the lower end of the rod 16. At the upper end of the rod 16 a non-self-locking thread is made. Between the rod 16 and the housing of the lantern 18 there is a stuffing box seal 19 of the rod 16. The lantern 18 in the upper part is fixedly connected to the housing 20 of the drive with a flange 21 and fastening elements. The drive consists of a nut 22 installed in the thrust bearings 23, and a slider 24, which progressively moves in the keyways of the housing 20.

In the upper part of the lantern 18 and the slider 24 there is a device that converts the translational movement of the rod 16 into a rotary, and then again into translational. The device consists of a nut 25 with a non-self-locking thread fixed in the slide 24 and mating with the stem 16 with the corresponding thread, a disk cup spring 26 installed in the lamp 18 with preliminary compression, the ring 27, the thrust bearing 28, two half rings 29 installed in the ring the groove of the rod 16 and held by two rings 30, a thrust bearing 28, a ring 31 and an adjustable support nut 32 fixed by a screw 33. The nut 22 is rotated by the flywheel 34. A shutter position indicator 35 is mounted on the rod 16.

The flange fastening of the withdrawal part of the lantern 18 and the flange 4 of the housing 1 is provided by the fasteners 36 and 37. The sealing is provided by the gasket 38. The connection of the flange 5 of the housing 1 with the plug 39 is carried out by the fasteners 40 and 41. The sealing is by the gasket 42.

Ball valve works as follows.

In the open position (figure 1), the passage opening of the segments 6 and 7 coincides with the holes of the nozzles 3 of the housing 1. The crane provides minimal hydraulic resistance.

When closing the valve, the flywheel 34 of the actuator rotates clockwise. The screw of the slider 24 (left-hand thread) is translationally moving downward, and the nut 25 with a non-self-locking thread of the slider 24, being in mesh with the end of the rod 16, rotates the latter with a lock by 90 °. The rotation takes place until the end of the slider 24 touches the ring 31, pre-pressed by the force of the disk spring package 26. The spherical surfaces of the disks 8 and 9 of the segments 6 and 7 stand opposite the sealing surfaces of the seats with a guarantee gap. With a further downward movement of the slider 24, the force is transmitted through the ring 31 to the bearing 28, the ring 30, the half rings 29, the ring 30, the bearing 28, the ring 27 and the disk spring package 26. In this case, the end of the rod 16, lowering down, spreads the levers 6 and 7, pressing the spherical surfaces of the disks 8 and 9 to the conical sealing surfaces of the seats 2, providing two-way closing of the valve. Between the ends of the support of the nut 32 and the ring 31, a gap A is formed.

When you open the crane (figure 2), the flywheel 34 of the drive rotates counterclockwise. The screw of the slider 24 translationally moves up and pulls the stem along the gap A. The end of the rod 16, through levers 14 and 15, diverts the sealing surfaces of the disks 8 and 9 of segments 6 and 7 from the conical sealing surfaces of the seats 2, ensuring a guaranteed clearance. After the clearance A has been selected, the force from preloading the disk spring package 26 through ring 27, bearing 28, ring 30, half rings 29, ring 30, ring 31, nut 32 closes on the lamp housing 18. The forward movement of the rod 16 stops, but the slide 24 continues to move . In this case, the nut 25 with a non-self-locking thread of the slider 24 and the rod 16 with the corresponding thread at the end are rotated with a lock by 90 ° until the position indicator 35 makes contact with the lamp housing 18. The crane is in the "open" position.

In the proposed design, the description is made for a ball valve, where the valve seal was provided for high-temperature working environments (above 200 ° C). Naturally, this design is also applicable for low-temperature environments (below 200 ° C), where a more effective seal of the shutter - metal-elastomer can be used.

When using a ball valve, especially on high-temperature environments, it is necessary to take into account the two-way tightness of the shutter, which can cause re-pressing of the valve body in its closed position. To protect against this undesirable phenomenon, a safety valve must be installed on the valve body.

Of particular interest is the proposed design of a ball valve for main pipelines, where large DN and PN valves are used and where the necessary condition is the two-way direction of the working medium.

Figure 3 presents a diagram of the use of a ball valve with unloading the shutter when opening and closing, which is possible only for the proposed shutter with two saddles. The internal cavity of the ball valve through the nozzle 36 is connected by a bypass line to the pipe 3 of the body 1 of the valve through the fittings 37 and 38. On the bypass line there is a small valve 39 and two check valves 40 and 41. When the ball valve is in the open position, the valve 39 is also open and the bypass line through the check valve 40 and the fitting 37 or the check valve 41 and the fitting 38 (depending on the direction of flow of the medium) is connected to the main pipeline. In the process of closing a ball valve (especially towards the end of closing), the force on the actuator is reduced due to the unloading of the shutter. After closing the ball valve, the bypass valve 39 closes. Before opening the ball valve, the valve 39 opens, the pressure of the medium inside the valve and in the cut-off line is equalized (dumped) almost instantly, since the volume of the internal cavity of the valve is significantly less than in the line. The shutter segment, together with the sealing surface of the disk, which is under the differential pressure, is unloaded and easy to open. And the opposite segment of the shutter with the sealing surface of the disk, on which the pressure differential continues to act, tends to spontaneously open, acting through the lever on the rod, and also reduces the drive force. The check valves 40 and 41 introduced into the bypass line, depending on the direction of the medium flow in the main pipeline, connect the bypass line after valve 39 with the corresponding cavity of the valve body nozzles.

Pilot manufacturing of the proposed design and testing proved its effectiveness compared to the prototype and fully confirmed its increased service life due to the high wear resistance of power elements in the form of multi-thread non-self-locking threads and lever-joint mechanisms that absorb high specific pressures when opening and closing the shutter under a differential pressure of the working medium. Two-way valve tightness significantly expands the functionality of the proposed design and is a full-fledged alternative to existing ball valves on clean and especially on contaminated working fluids, as it has a higher cycle life and high tightness of a two-way valve throughout operation.

The use of a ball valve with unloading by-pass line significantly expands its functionality for use on main pipelines with large DN and PN with low drive forces.

Claims (9)

1. Ball valve, comprising a housing with an inlet and outlet opening and a supporting surface made in its lower part, a seat with a conical sealing surface, a withdrawn part consisting of a ball valve with a spherical surface, a lamp with an oil seal, an actuator with a reciprocating rod and a device leading to the interaction of the sealing surfaces of the ball valve and the housing seat, characterized in that the housing is equipped with a second seat located opposite the first seat, the ball valve is made of two x movable segments with disks on which sealing surfaces are made, movable segments are pivotally interconnected via an axis installed in the supporting surface of the housing, and in the upper part, each segment through pivoted levers with axes is pivotally connected to the lower end of the rod, which after rotation and alignment the sealing surfaces of the ball valve provides compression of the sealing surfaces during its further translational movement, and the introduced device that converts the translational motion The rod with a rotary bolt consists of a nut with a non-self-locking thread installed motionlessly in the inserted drive slider and interacting with the corresponding rod thread, and further translational movement of the rod is provided by the inserted support parts of the device, which transmit the force from the rod to the disk spring package installed with preliminary pressing in the lamp housing. 2. Ball valve according to claim 1, characterized in that the supporting parts of the device are located coaxially relative to the rod and consist of two half rings installed in the annular groove of the rod, two rings holding the half rings, two thrust bearings that sense the rotation of the rod, and two rings, centering thrust bearings. 3. Ball valve according to claim 1, characterized in that the optimal location of the sealing surfaces of the shutter with seats after rotation is fixed by turning the actuator housing relative to the lamp housing by an inserted flange. 4. Ball valve according to claim 1, characterized in that the supporting surface of the housing is made in the form of a nut with the ability to adjust and fix it relative to the housing. 5. Ball valve according to claim 1, characterized in that for fixing the stroke of the rod to open the shutter, a fixed nut is introduced located in the actuator housing. 6. Ball valve according to claim 1, characterized in that to control the position of the valve shutter on the rod perpendicular to the axis of the latter is a pointer. 7. Ball valve according to claim 1, characterized in that at the end of the rod is fixedly mounted coupling transmitting torque when the shutter is rotated. 8. Ball valve according to claim 1, characterized in that the sealing surfaces of the shutter are made on hermetically mounted removable disks and serve simultaneously as compensators to ensure synchronous preloading of the sealing surfaces of the shutter. 9. The ball valve according to claim 1, characterized in that the discharge of the shutter in any direction of the working medium is provided by an introduced bypass line having a shut-off valve at the outlet of the internal cavity of the valve and two check valves installed each on the line of the inlet and outlet of the valve and connecting internal cavity of the crane with an outlet.

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