RU2313713C2 - Check valve with axial direction of flow - Google Patents

Abstract

FIELD: pipeline valves and fittings.

SUBSTANCE: invention relates to check valves and it can be used for cutting off reverse flow in high-pressure gas main lines. Proposed check valve with axial direction of flow has outer housing with inlet and outlet channels. Inner cone-shaped member in form of Venturi nozzles is made in inner space of housing to form ring channel. Shutoff member is installed in support cup of said member by means of bearing unit. Said shutoff member is made in form of rod with disk and is provided with spring displacement mechanism. Disk is in contact with seat over working surface. Seat is made in form of ring with contact conical surface inscribing seat into profile of ring channel. Seal of seat made in form of stressed two-layer U-shaped element. Said element is installed with its inner space opposite to cutoff flow in ring slot of outer housing in zone of contact conical surface of seat. Bearing unit of shutoff member is formed by at least two relatively overlapping bushings corresponding in assembly to length of support cup of inner cone-shaped member. Zone of overlapping of bushings is made stepped. Length of each zone of overlapping is minimum half as large as thickness of walls of bushings working surface of disk of shutoff member is formed by mated surfaces of sphere and torus, with radius of sphere 3.5 times greater than radius of torus. Tilting of conical contact surface of seat to longitudinal axis of valve is set at angle not exceeding 43 degrees.

EFFECT: improved reliability of valve owing to increased sealing of valve.

5 cl, 4 dwg

Description

The present invention relates to the field of valve engineering, in particular to check valves for high-pressure gas lines.

A self-sealing check valve is known, comprising a locking member located with the possibility of movement in the tubular body, loaded with a compression spring with a force against the direction of flow and pressed against the seat (1) made in the inlet channel. The locking element in the area of the sealing surfaces is limitedly compliant. The sealing surfaces of the locking element and the seat are made curved. In the locking body in the area adjacent to the sealing surface, an annular channel is made, communicating with the radial holes. The compression spring is mounted with support in the bottom of the blind hole of the locking member and is preloaded with a set screw that enters the threaded hole made in the housing.

A disadvantage of the known valve is the presence of a compliant zone on the surface of the shutoff member, subject to wear and damage, which reduces the reliability and tightness of the valve during operation.

Another disadvantage of the valve is the difficulty of adjusting the valve to operating pressure, as the locking body in the tubular body is moved with metal-to-metal friction and it needs to be taken into account in the spring loading force, which is difficult during operation when performing such operations with a set screw.

Also known is a shutoff valve comprising an outer casing and an inner casing housed therein, forming an annular passage for a controlled environment (2). In the inner case, with the possibility of movement along the longitudinal axis of the valve, a shut-off element with a conical and cylindrical parts of the surface is installed, pressed by the conical part to a seat installed in the outer case in the inner zone of the inlet channel. The horizontal part of the surface of the locking member is in contact with the inner surface of the inner housing. The saddle is made with a conical surface that fits into the profile of the input channel, while the angle of the cone of the surface in contact with the surface of the locking member is different from the angle of the conical surface of the latter. The locking body is equipped with a movement mechanism and is removed from the inner case by the force of a spring mounted on a rod connected to a piston moving in a sleeve fixed at the top of the conical part of the inner case by a threaded connection. The inner space of the sleeve is connected to the inner space of the inner casing by radial holes, one of which is a throttle. At least one radial hole is made in the body of the locking member, connecting the annular channel with the inner cavity of the inner case.

A disadvantage of the design of the known valve is the limited range, and not high pressures, in which it is possible to use the valve. This is due to the insufficient streamlining of the surface of the locking member formed by the cylindrical and conical surfaces having a joint, and the insufficient rigidity of the fastening mechanism for moving the locking member in the inner case. The presence of a junction at the junctions of the conical and cylindrical surfaces of the locking element and the inner housing at high pressures affects the hydrodynamic characteristics of the passage channel, which can cause unstable operation of the valve.

The fastening of the mechanism for moving the locking member at the top of the conical part of the inner case does not provide sufficient rigidity of the assembly, which at high pressures can lead to vibrations of the locking member, additional non-calculated impacts on the surface of the seat, leading to destruction of the latter, to damage to the contacting surfaces of the inner case and locking member and, as a consequence, to a loss of reliability and tightness of the valve and to an increase in its noise characteristics.

The closest to the inventive valve for the intended purpose and technical essence is a non-return valve with an axial direction of flow, containing an outer casing with inlet and outlet channels, in the cavity of which an internal cone-shaped support element is fixed with a rod of a locking member placed in it, made in the form of a disk with a spherical and a cone-shaped contact working surface, and a saddle in the form of a ring (3). The locking element is movably mounted in the cavity of the inner cone-shaped supporting element by means of a movement mechanism. The mechanism for moving the locking element includes a compression spring mounted on a rod moving in sliding bearings fixed in the guide cup of the inner cone-shaped supporting element. The spring serves to close the valve, the opening of which occurs under the influence of the hydrodynamic forces of the passing stream. The saddle is made in the form of a ring with a conical surface in contact with the surface of the sphere of the locking member. The conical contact surface of the seat mounted in the inner cavity of the outer casing and the spherical shape of the inner cavity in the outer casing determine the shape of the annular channel between the surfaces of the outer and inner casings, forming an inlet section of the valve in the form of a Venturi pipe with the inlet pipe.

On the contact conical surface of the disk of the locking body, a groove is made to accommodate the seal.

The disadvantage of the valve is the relatively large contact area of the locking member and the seat, due to the contact of the conical side surface of the locking disc and the tapered contact surface of the seat. The large contact surface of the locking element and the seat during valve operation requires a large effort to press the locking disk of the valve, and the impact on it of mechanical inclusions of the transported stream, causing erosion processes, leads to a decrease in the reliability and tightness of the valve.

A disadvantage of the known valve is the presence of a relatively soft seal on the surface of the disk of the locking member, subject to wear and damage, which reduces the tightness of the valve during operation. In addition, the placement of the sealing seal in the open groove on the lateral surface of the disk of the locking body does not allow you to set the compression force in the seat and determine the initial shape of the seal, sufficient to ensure the required valve tightness.

Reliability of the valve is also reduced as a result of the formation on the surfaces of the stem and sliding bearings of deposits formed from particles of impurities and mechanical impurities contained in the flow of the transported medium, and from corrosion products of the metal of the support cup.

The aim of the invention is to increase reliability and maintain valve integrity during the entire life cycle.

This goal is achieved by the fact that in the valve with the axial direction of flow, containing an outer casing with inlet and outlet channels, in the inner cavity of which is made, with the formation of an annular channel with a profile in the form of a Venturi nozzle, an inner cone-shaped element, in the supporting cup of which of the bearing assembly, a locking member is installed, equipped with a spring movement mechanism and made in the form of a rod with a disk having a working surface along which it contacts a saddle made in the form rings with a contact conical surface inscribing the saddle into the annular channel profile, wherein the saddle is provided with a sealing seal; according to the invention, the sealing seal of the saddle is made in the form of a strained two-layer U-shaped element installed in the annular groove of the outer casing in the direction of the contact conical surface of the saddle with an internal cavity towards to the cut-off flow, the bearing assembly of the locking assembly is represented by at least two mutually overlapping bushings corresponding to the assembly for without a support cup, while the overlapping zones of the bushings are made stepwise, and the length of each overlapping zones of the bushings exceeds the wall thickness of the bushings by at least 1.5 times, in addition, the working surface of the locking disk is formed by the mating surfaces of the sphere and torus with the radius of the sphere exceeding with respect to the radius of the torus is not less than 3.5 times, and the inclination of the contact conical surface of the seat to the longitudinal axis of the valve is set at an angle not exceeding 43 °, while the voltage of the sealing seal of the seat is set to the formation of its initial V-shaped profile in a U-shaped by installing it in the annular groove of the body when installing the seat, and the annular groove of the body is made with the installation groove, which has an angle of inclination to the valve axis not exceeding 15 °, and the sealing seal of the seat is made of polytetrafluoroethylene or polyurethane and is equipped with an elastic plate.

The implementation of the sealing seal in the form of a strained two-layer U-shaped element installed in the annular groove of the outer casing in the area of the contact conical surface of the saddle with the internal cavity facing the cut-off flow, improves the reliability and tightness of the valve. The voltage of the two-layer seal created when it is installed in the annular groove of the casing closed by the annular groove of the saddle is predetermined due to the change in shape from V-shaped to U-shaped, and ensures its tight placement in the ring groove of the outer casing formed by closable grooves, and the installation of the seal internal cavity in the direction of the cut-off flow allows you to include in the pressure force of the seal to the walls of the annular grooves of the saddle and the housing the force of the pressure of the return flow medium, thereby increasing the reliability of the valve in the reverse flow mode overlap. The value of the specified voltage of the U-shaped seal is determined by the size of the initial V-shaped seal and the size of the annular grooves of the seat and body, and affects the degree of tightness of the valve.

The execution of the annular groove in the outer casing with the installation groove facilitates closure of the seal with the annular groove of the outer surface of the saddle and the formation of the required voltage in the two-layer U-shaped seal. The implementation of the U-shaped seal with two layers ensures the maintenance of a constant value of its voltage.

The implementation of the bearing assembly of the rod in the form of at least two mutually overlapping bushings with a length corresponding to the assembly of the length of the support cup, increases the reliability of the valve by ensuring the reliability of operation of the locking element. The installation of mutually overlapping bushings along the entire length of the support cup, with a length of the overlapping zone exceeding the thickness of the wall of the bearing bush by at least 1.5 times, eliminates particles of mechanical impurities entering the bearing assembly and onto the surface of the rod, which prevents the formation of deposits on the surfaces of these elements and excludes braking and sticking of the rod during movements. The specified length of the overlapping zone provides a correlation of its size with the particle size of impurities in the flow of the transported medium, which prevents the latter from entering the protected zone (on the surface of the rod and the inner surface of the bearing sleeve).

The formation of the working surface of the disk of the locking body by the conjugate surfaces of the sphere and the torus, with the radius of the sphere exceeding the radius of the torus by at least 3.5 times, provides a decrease in the contact surface area of the disk with the conical contact surface of the saddle due to an increase in the curvature of the disk surface in the contact zone . Reliability of the valve is increased by increasing the specific pressure of the disk surface on the conical contact surface of the seat, created by the action of the spring of the locking member, and complemented by the force of the return flow of the transported medium to its surface. The specified ratio of the radii of the spherical surface and the surface of the torus in the formed working surface of the disk allows you to save the reliability and tightness of the valve for all sizes.

The implementation of the contact conical surface of the saddle at an angle to the valve axis, not exceeding 43 °, gives the specified surface of the saddle the properties of the guide wedge surface, acquiring the functions of a catcher. This allows you to reduce the effect of misalignment of the seat relative to the axis of the valve on the alignment of the locking element and the seat and maintains the reliability of the valve during operation.

In addition, the specified angle of inclination of the contact conical surface of the saddle determines the smooth conjugation of the surfaces of the housing and the saddle, which ensures a smooth flow of the transported medium and the stability of the valve due to the absence of impact on the shut-off element of the turbulence of the flow of the transported medium.

An example implementation of the inventive check valve with an axial direction of flow is shown in the drawings.

Figure 1 in section shows the inventive check valve with an axial direction of flow,

Figure 2 presents the remote element E is a locking body,

Figure 3 shows the remote element W - bearing unit,

Figure 4 shows the remote element And the sealing seal of the saddle.

The valve comprises an outer housing 1 with inlet A and outlet B channels. An inner supporting element 2 is installed in the inner cavity of the outer casing, which forms an annular channel B for the passage of the working medium with the outer casing, and an annular seat 3. In the cavity G of the inner supporting element 2, a locking member 4 with a working surface D made in the form of mating surfaces spheres 5 and torus 6. The mechanism for moving the locking member comprises a rod 7 mounted in a sliding bearing made of at least two mutually overlapping bushings 8 and 9 fixed in a glass 10, which I am the inner part of the supporting element 2 (figure 3). The zone 11 of overlapping bushings 8 and 9 is made stepwise and its length is greater than the wall thickness of the bushings by at least 1.5 times. The locking element 4 is pressed by a spring 12 to the seat 3, contacting on its conical end surface 13, the angle of inclination of which to the longitudinal axis of the valve does not exceed 43 °. Between the seat 3, fixed in the inlet channel A of the valve, and the inner surface of the housing 1 in the annular groove 14, a stressed U-shaped seal is made of elastic 15 and elastic 16 layers.

The shape of the strained U-shaped seal is determined by the shape of the surfaces of the annular grooves 17 and 18 closing it, forming an annular groove 14 and made respectively on the inner surface of the casing and the outer surface of the saddle, while the annular groove 17, made on the inner surface of the casing, is provided with an installation groove 19, the surface of which is inclined to the longitudinal axis of the valve at an angle of 15 degrees.

The housing of the inner supporting element 2 has a supporting surface 20, the shape of which is in response to the surface 21 of the locking member 4.

The valve is shown closed when flow direction is arrow K.

Spring 12, the locking element 4 is pressed against the seat 3, closing the input channel A. In this case, the rod 7 is in the extreme right position. When the pressure of the transported medium in the input channel A and the hydrodynamic flow forces exceed the force of the spring 12, the shut-off element 4 moves away from the surface of the seat 3, opening the passage of the transported medium into the annular channel B and compressing the spring 12. The compression force of the spring is determined by the working pressure in the working stream environment and is given constructively. The rod 7 moves in a sliding bearing made of two bushings 8 and 9. The length of the bushings 8 and 9 of the sliding bearing corresponds to the assembly of the length of the cup 10, and the length of the zone 11 of their overlap exceeds 1.5 times the wall thickness of the bearing sleeve. When the rod 7 is moved in the unloading chamber L of the inner supporting element 2, increased pressure is created that counteracts the compression force of the spring, which prevents a shock when the surface 21 of the locking member 4 approaches the end surface 20 of the inner supporting element 2. The valve opens, allowing the passage of the working medium.

When equalizing the pressure in the output channel B and in the input channel A, the influence of the hydraulic forces of the transported medium on the shut-off element 4 is eliminated, and under 8 the action of the spring 12 it smoothly presses the surface 6 to the conical end surface 13 of the seat 3. The valve is hermetically closed, preventing the flow of the transported environment in the opposite direction and providing increased tightness due to the tense two-layer U-shaped seal of the saddle.

Thus, the proposed implementation of the valve elements provides the maintenance of the specified valve tightness in the closed state, which increases the reliability of the valve and the ability to work in flows with variable mode.

Information sources

1. Description of the patent of the Russian Federation No. 1838702 by class. F 16 K 15/02. "Self-sealing valve", according to the application No. 4614987/29 of 09/28/89, published on 08/30/93 in bull. Number 32.

2. Description of the application to Germany No. 36 10 965 A1 by class. F 16K 15/02. "Check Valve" dated 2.04.86, published on 10.10.87.

3. Description of US patent No. 5921276A for class F 16 K 15/06 from 10/17/1995, (prototype).

Claims (5)

1. The check valve with an axial direction of flow, containing an outer casing with inlet and outlet channels, in the inner cavity of which is formed with an annular channel with a profile in the form of a Venturi nozzle, an internal cone-shaped element, in the supporting cup of which, by means of a bearing assembly, a shut-off element equipped with a spring a movement mechanism and made in the form of a rod with a disk having a working surface along which it contacts a saddle made in the form of a ring with a contact conical surface , inscribing the saddle into the annular channel profile, wherein the saddle is provided with a sealing seal, characterized in that the sealing seal of the saddle is made in the form of a strained two-layer U-shaped element installed by the internal cavity towards the cut-off flow in the annular groove of the outer casing in the area of the contact conical surface of the saddle, the bearing assembly of the locking member is represented by no less than two mutually overlapping bushings corresponding in assembly to the length of the support cup of the inner cone a shaped element, while the overlap zone of the bushings is made stepwise, and the length of each overlap zone exceeds the wall thickness of the bushings by at least 1.5 times, in addition, the working surface of the shutter disc is formed by the mating surfaces of the sphere and torus when the radius of the sphere exceeds the radius torus not less than 3.5 times, and the inclination of the conical contact surface of the seat to the longitudinal axis of the valve is set at an angle not exceeding 43 °. 2. The check valve with the axial direction of flow according to claim 1, characterized in that the voltage of the sealing seal of the saddle is set by converting its initial V-shaped profile to a U-shaped. 3. A non-return valve with an axial flow direction of 2, characterized in that the U-shape of the valve sealing seal is set by closing the annular grooves made in the body and seat, while the annular groove in the body is made with an installation groove. 4. The check valve with the axial direction of flow according to claim 3, characterized in that the surface of the installation groove of the annular groove of the body has an angle of inclination to the valve axis not exceeding 15 °. 5. The check valve with the axial direction of flow according to claim 1, characterized in that the sealing seal of the seat is made of polytetrafluoroethylene or polyurethane and is equipped with an elastic plate.

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