RU220550U1 - Axisymmetric control valve - Google Patents

Abstract

The utility model relates to pipeline fittings, in particular to control valves designed to regulate pressure in specified sections of the pipeline. The axisymmetric control valve contains a body (1) with inlet (2) and outlet (3) pipes and a fairing (5) located inside the body to form an annular channel. The outlet part of the valve is covered by a separator (14) with holes, rigidly connected to a seat (18) fixed in the outlet pipe (3). Inside the seat (18), with the possibility of axial movement, there is a piston (13) mounted on the rack (9) of the rack and pinion mechanism. The rod (10) of the rack and pinion mechanism is connected to the drive. The piston (13) is made with unloading channels at the end. The helical gearing of the rack and pinion mechanism and the free ends of the rod (10) and rack (9) are located in the cavities formed for them. In this case, the cavities of the helical gear and the end of the rod (10) are isolated from the pressure of the working medium. In the groove of the guide bushing (7) and in the groove of the rack (9) bearings 28 and 29 are installed, respectively, with a low coefficient of friction made of a composite material made of polytetrafluoroethylene with additives. Glass fiber and molybdenum disulfide are used as additives. The reliability of the valve is ensured. 3 ill.

Description

The utility model relates to pipeline fittings, in particular to control valves designed to regulate pressure before and after installing the valve on specified sections of the pipeline by throttling the flow of the working medium, at newly built and reconstructed existing facilities of the linear part of main pipelines and pumping stations at main oil pipeline facilities and petroleum product pipeline transport.

An axisymmetric axial flow control valve is known, containing a housing with inlet and outlet pipes and a fairing placed inside the body to form an annular channel, the outlet of which is covered by a separator perforated with holes, rigidly connected to a seat fixed in the outlet pipe, and placed inside it with the possibility of axial movement. a piston mounted on the rack of a rack and pinion mechanism, the rod of which is connected to the drive, the piston is made with unloading channels at the end, and the helical engagement of the rack and pinion mechanism and the free ends of the rod and rack are located in cavities formed for them, the cavities of the helical engagement and the end of the rod are isolated from the working pressure environment (Patent RU No. 191873 U1, IPC F16K 1/12, F16K 1/226, F16K 47/08, priority dated January 10, 2019, published August 26, 2019).

The closest in purpose, technical essence and achieved result to that claimed as a utility model is an axisymmetric control valve, containing a body with inlet and outlet pipes and a fairing placed inside the body to form an annular channel, the outlet of which is blocked by a separator perforated with holes, rigidly connected to a seat fixed in the outlet pipe, and a piston placed inside it with the possibility of axial movement, fixed to the rack of the rack and pinion mechanism, the rod of which is connected to the drive, the piston is made with unloading channels at the end, and the helical engagement of the rack and pinion mechanism and the free ends of the rod and rack are located in cavities formed for them, while the cavities of the helical gear and the end of the rod are isolated from the pressure of the working medium, a guide bushing with a channel in the form of an annular groove on the outer surface at the point of connection with the fairing plug with channels in the form of through windows for the flow of medium (RU Patent No. 196436 U1, IPC F16K 1/12, F16K 47/14, priority from 09.09.2019, publ. 02/28/2020).

A disadvantage of the known valve designs is the increased friction in the rack and pinion pair when the valve moves, which results in an increase in the drive force required to move the rack; wedging and jamming are possible when the valve moves, which reduces the reliability of the valve.

The technical problem that the utility model is aimed at solving is ensuring the reliability of the valve by installing bearings with a low coefficient of friction, which reduces friction between the rack and the guide bushing.

To solve a technical problem in an axisymmetric control valve containing a housing with inlet and outlet pipes and a fairing placed inside the body to form an annular channel, the outlet part of which is covered by a separator with holes, rigidly connected to a seat fixed in the outlet pipe, and placed inside it with the possibility axial movement of the piston mounted on the rack of the rack and pinion mechanism, the rod of which is connected to the drive, the piston is made with unloading channels at the end, and the helical engagement of the rack and pinion mechanism and the free ends of the rod and rack are located in cavities formed for them, while the cavities of the helical engagement and the end of the rod are isolated from the pressure of the working medium, according to the utility model, low-friction bearings made of a composite material made of polytetrafluoroethylene with additives are installed in the groove of the guide bushing and in the groove of the rack.

Glass fiber and molybdenum disulfide are used as additives.

Installation of low-friction bearings made of a composite material made of polytetrafluoroethylene with additives, for example, glass fiber and molybdenum disulfide, into the guide bushing and rack ensures sealing of the rack mechanism cavity, as well as centering of the rack mechanism, prevents metal-to-metal contact between the rack and the guide bushing, in As a result, the reliability of the rack and pinion mechanism increases. Due to the centering property of the bearings, the load on the seals is reduced, and therefore there is less wear on the seal. In turn, the reduced load on the seals and the low coefficient of friction of the bearings help reduce the force on the actuator when moving the valve rack. As a result, the reliability of the valve operation is increased.

The axisymmetric control valve is illustrated by drawings where:

in fig. 1 - shows a general view of an axisymmetric control valve, longitudinal section;

in fig. 2 - view A in Fig. 1 shows the location of the bearing in the groove of the rack.

in fig. 3 - view B in Fig. 1 shows the location of the bearing in the groove of the guide bushing.

When describing an axisymmetric control valve, the positions in the drawings indicate:

1 - body;

2 - inlet pipe;

3 - outlet pipe;

4 - flanges;

5 - fairing;

6 - annular passage channel;

7 - guide bushing;

8 - nut;

9 - rack;

10 - rod;

11 - nut;

12 - washer;

13 - piston;

14 - separator;

15 - support ring;

16 - seal;

17 - threaded clamping bushing;

18 - saddle;

19 - seal between the seat and the separator;

20 - seat seal;

21 - screw;

22 - seal along the guide bushing;

23 - seal along the guide bushing;

24 - rubber rings along the guide bushing;

25 - seal along the rail;

26 - seal along the guide bushing;

27 - nut;

28 - bearing;

29 - bearing;

30 - bushing on the rod;

31 - bearing;

32 - seal;

33 - support ring;

34 - rings;

35 - seal;

36 - nut.

The axisymmetric control valve contains a housing 1 with 2 inlet and 3 outlet pipes. The valve body 1 is made of one-piece casting with flanges 4 for joining with the pipeline. The central part of the body 1 is made in the form of a fairing 5, mounted on two ribs that are integral with the body 1, and forms an annular passage channel 6 (Fig. 1). On the right, in the fairing 5 of the body 1, there is a groove for installing the guide bushing 7 of the rack and pinion mechanism, secured with a nut 8.

The guide bushing 7 has two mutually perpendicular holes, machined with high precision. In the horizontal hole there is a rack 9, and in the vertical hole there is a rod 10. The rack 9 and the rod 10 are equipped with teeth cut at an angle of 45 degrees relative to the axis and, interacting with each other through the said teeth, are capable of reciprocating movement. When rod 10 moves down, rack 9 moves to the right (to close the valve). When rod 10 moves upward, rack 9 moves to the left (to open the valve). The cylindrical surfaces of the holes in the sleeve 7, as well as the surfaces of the rack 8 and rod 9, have a high-strength coating, which ensures scuff-free operation of the mechanism and minimal friction.

At the right (according to the diagram) end of the rack 9, a piston 13 is installed by means of a nut 11 and a washer 12, which moves back and forth together with the rack 9. The outer surface of the piston 13 is strengthened by ion nitriding and interacts with the inner surface of the separator 14 installed in the bore of the fairing 5 housing 1. The piston 13 is centered relative to the inner surface of the separator 14 in the presence of a constant minimum gap between the outer surface of the piston 13 and the inner surface of the separator 14. This ensures a minimum coefficient of friction in the piston-separator pair.

To equalize the force on the piston 13 and the rack 9 from the action of the differential pressure of the working medium, the cavities in the valve on one and the other side of the ends of the rack 9 are made communicating. Pressure equalization occurs through the holes in the piston 13, the holes in the guide bushing 7, the channels and the cavity in the fairing 5 of the body 1.

The separator 14 has several rows of holes and a number of grooves. The outer and inner surfaces of the separator 14 are strengthened by ion nitriding. On the left (according to the diagram) the separator 14 rests against the body 1. A support ring 15 and a seal 16 are installed in the groove of the body 1, ensuring the tightness of the valve in the closed position.

A seat 18 is attached to the right (according to the diagram) end of the separator 14 with a threaded clamping sleeve 17. To ensure the tightness of the piston 13 in the closed position, a seal 19 is installed in the cavity formed by the profiled surfaces of the separator 14 and seat 18. A seal 20 is installed in the seat 18. Threaded clamping sleeve 17 is secured against unscrewing with screw 21.

The internal cavities of the rack and pinion mechanism are isolated relative to the working environment in order to eliminate the buoyancy force from the pressure of the working environment on the rod 10. The tightness of the internal cavities of the rack and pinion mechanism is ensured by:

along the guide bushing 7, seals 22, 23, rubber rings 24;

along rail 9 - seals 25, 26 (Fig. 2, 3). Seal 25 is installed in the groove of rack 9, and seal 26 is installed in the groove of guide bushing 7 and secured with nut 27, in which a wiper is located to protect the cuffs from mechanical impurities.

Rack 9 is centered using low-friction composite bearings:

in the groove of the guide bushing 7 - by bearing 28;

groove of rack 9 - bearing 29.

Low friction bearings 28 and 29 are made of a composite material of polytetrafluoroethylene with additives, while additives are used, for example, glass fiber and molybdenum disulfide, which ensures sealing of the rack and pinion cavity, as well as centering of the rack and pinion and prevents metal-to-metal contact between rail 9 and guide bushing 7, and thereby reduces friction between them.

The upper end of the rod 10 is centered in the body using a sleeve 30. A bearing 31, a seal 32 with a support ring 33, rings 34, a seal 35 are installed in the sleeve 30, ensuring the tightness of the valve with respect to the external environment in the event of failure of the internal sealing elements of the guide sleeve 7 and racks 9. The sleeve 30 is fixed in the body using a nut 36, in which the wiper is installed.

The direction of movement of the working medium is one-way, in the direction of the arrow on the body. The valve has an external anti-corrosion coating.

The valve works as follows.

The principle of operation of the valve is to maintain pressure “before itself” and “after itself”, throttling the flow of the medium by moving the regulating body, which is the piston 13 along the axis of the separator 14. In this case, a certain number of through holes in the separator 14 opens or closes, which entails entails a change in the valve flow area.

In the closed position of the valve, piston 13 occupies the extreme right position. In this case, the seal is carried out by pressing the piston 13 against the seal 20, which is pressed against the surface of the piston 13 due to compression resulting from the presence of a pressure difference in the working medium.

The controlled medium enters the inlet pipe 2 and, passing through the annular channel 6 formed by the body 1 and the fairing 5, through the radial holes of the separator 14, enters the outlet pipe 3. If it is necessary to reduce the volume of the controlled medium (when closing the valve), the piston 13 by means of the rack 9 and rod 10, is shifted by the drive to the right position, blocking the holes of separator 14. The volume of the passing controlled medium is determined by the number of open holes in separator 14. When the holes of separator 14 are completely blocked, the valve is closed.

To move the valve from the “closed” position to the “open” position, a control signal is sent to the actuator. The actuator rod moves upward in accordance with the magnitude of the control signal. The drive force is transmitted to the rod 10, which, through teeth, interacting with the rack 9, moves it, and, accordingly, the piston 13 attached to the rack 9, to the left to open. Piston 13, moving to the left, opens a certain number of holes in the separator 14, providing a given flow and pressure of the oil product.

Closing the valve is similar to opening in the opposite direction. When a “closing” signal is given, the drive moves the rod 10 down, thereby ensuring that the rack 9 with the piston 13 moves to the right to close.

Thus, the result of improving the design of an axisymmetric control valve is to increase its reliability, maintaining stable operation of the valve by installing rack-mounted bearings in the valve to reduce friction (metal/polymer instead of metal/metal).

Claims (2)

1. An axisymmetric control valve containing a body with inlet and outlet pipes and a fairing placed inside the body, in which a guide bushing is installed, while the fairing forms a flow-through annular channel of the valve body, the outlet of which is blocked by a separator with holes, rigidly connected to a seat fixed in outlet pipe, and a piston placed inside it with the possibility of axial movement, mounted on the rack of the rack and pinion mechanism, the rod of which is connected to the drive, the piston is made with unloading channels at the end, and the helical engagement of the rack and pinion mechanism and the free ends of the rod and rack are located in the cavities formed for them , while the cavities of the helical gear and the end of the rod are isolated from the pressure of the working medium, characterized in that low-friction bearings made of a composite material made of polytetrafluoroethylene with additives are installed in the groove of the guide bushing and in the groove of the rack. 2. An axisymmetric control valve according to claim 1, characterized in that glass fiber and molybdenum disulfide are used as additives.