RU2230965C2 - Check valve with axial direction of flow - Google Patents

Abstract

FIELD: mechanical engineering; valves and fittings.

SUBSTANCE: invention is designed for use in high-pressure gas mains for preventing back flow of gas. Proposed valve contains outer housing with inlet and outlet channels. Inner-shaped housing is rigidly secured in inner space of valve housing to form ring channel in form of Venturi nozzle. Shutoff member with working surface in form of part of sphere in contact with seat is installed in cone-shaped housing by means of displacement mechanism. Seat is made in form of ring with contact conical surface inscribing the seat into profile of ring channel. Displacement mechanism is provided with compression spring installed on rod. Rod moves in sliding bearings installed in guide bushing. The latter is rigidly secured in inner housing. Seat and inner housing are installed in ring slots made, respectively, on inner surfaces of inlet and outlet channels of outer housing. Seat and inner housing are fixed on surfaces of slots perpendicular to longitudinal axis of valve. Fixing is done by threaded fasteners. Seal is placed between seat and fixing surface. Said is placed between seat and fixing surface. Said seal is made of material featuring elastic deformation properties, for instance, graphite containing material. Guide bushing has union nut in ring groove of which made n end face part, scraper is installed in form of ring made of elastic material. Scraper is in contact with surface of rod.

EFFECT: improved reliability of valve owing to provision of stable sealing in process of its service life.

2 cl, 4 dwg

Description

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

Known self-sealing check valve, comprising a locking body located with the possibility of movement in the tubular body, loaded with a compression spring, with an effort against the direction of flow, and pressed against the seat (1) made in the inlet channel. The locking body, in the area of the sealing surfaces, is made limitedly compliant. The sealing surfaces of the locking element and the seat are made curved. In the closure body, in the area adjacent to the sealing surface, an annular channel is made, communicating with 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 shut-off member, subject to wear and damage, which reduces the tightness of the valve during operation. Another disadvantage of the valve is the difficulty of adjusting the valve to operating pressure, as the movement of the shut-off member in the tubular body is accomplished 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. In addition, the valve design does not provide for the possibility of replacing internal elements, which makes it difficult to repair.

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 casing with the possibility of movement along the longitudinal axis of the valve, a locking element with a conical and cylindrical parts of the surface is installed, which is pressed by the conical part to the seat installed in the outer casing 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, low pressure, in which it is possible to use the valve. This is due to insufficient streamlining of the internal surfaces having joints of conical and cylindrical surfaces and insufficient rigidity of the fastening mechanism for moving the locking member in the inner case. The presence of joints at the junctions of the conical and cylindrical surfaces of the shutoff member and the inner housing at high pressures affects the hydrodynamic characteristics of the passage channel, which can cause unstable valve operation. 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 result, to loss of valve tightness and increase of its noise characteristics.

Also known is a non-return valve with an axial direction of flow, comprising an outer cast housing, in a spherical cavity of which an inner cone-shaped housing (3) is rigidly fixed. In the inner case movably, by means of a movement mechanism, a locking member is installed with a working surface in the form of a part of a sphere having a mating surface in contact with the end of the inner case. The locking body is equipped with a movement mechanism comprising a compression spring mounted on a rod moving in sliding bearings fixed in a guide sleeve. The spring serves to close the valve, the opening of which occurs under the influence of the hydrodynamic forces of the passing stream. A saddle is mounted on the inner surface of the outer casing, in the valve inlet channel, fixed by means of a thread on the channel surface and the surface of the saddle facing it. The saddle is made in the form of a cylinder and contacts the surface of the sphere of the locking organ with a conical surface at the end. A sealing seal is installed in the area of the threaded surface of the seat. The shape of the saddle with the conical contact and cylindrical parts, the conical surface of the inner 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 in the form of a Venturi nozzle.

The disadvantage of the valve is the possibility of damage to the seals when installing the seat, which will reduce the tightness of the valve, which is one of the parameters that determine the applicability of valves for main pipelines, i.e. the possibility of using it at high pressures, and the reliability of the design. The placement of the sealing seal on the side surface of the seat does not allow to calculate the compression force in the seat and to accurately determine the initial shape of the seal, sufficient to ensure the required tightness. In addition, the threaded connection on the side surface of the seat, which is subjected to lateral impact loads from the side of the locking member, deforms over time, causing the seat to move and reduce valve tightness. The tightness of the valve can be reduced due to deposits formed from the particles of impurities and mechanical inclusions contained in the flow of the transported medium that form during the operation on the surfaces of the sliding bearings and the rod stem.

Closest to the claimed valve, the opposite in 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, in grooves made on the inner surface of the inlet and outlet channels, are fixed by threaded connections inner cone-shaped body of the locking member and a seat in the form of a ring (4). On the inner casing by means of a movement mechanism located in the cavity of the inner casing, a locking member with a working surface as a part of a sphere is movably mounted. The mechanism for moving the locking member includes a compression spring mounted on a rod moving in sliding bearings fixed in the guide sleeve. 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 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 nozzle with the inlet pipe.

The disadvantage of the non-return valve is its unreliability in operating conditions at high and variable pressures of the transported media and the possibility of reducing tightness. As a result of the impact on the saddle of the loads arising from the actuation of the locking element, the threaded fastening of the saddle is subjected to lateral impact loads. When the calculated pressures are exceeded in the transported medium, loads arise that lead to the deformation of the threaded fastenings of the saddle and the inner housing of the locking element. When the threaded fastening of the seat and the inner casing is deformed, a change in their position occurs, the valve tightness is lost.

The probability of a change in the position of the seat and the inner casing as a result of deformation of their threaded fasteners reduces the reliability of the valve and imposes restrictions on the pressure range of the transported medium for which the non-return valve is intended.

Threaded connections on the lateral surfaces of stiffeners, which attach the inner casing, are also subjected to lateral loads. These loads are directional and are determined by the effect of the flow of the transported medium passing through the valve on the shut-off element. With prolonged use and heavy loads, threaded connections also undergo deformation.

Reliability of the check valve and its tightness can also be reduced due to deposits formed from the particles of impurities and mechanical inclusions contained in the flow of the transported medium that form during operation on the surfaces of the rod of the displacement mechanism of the shutoff member and sliding bearings.

In addition, the known valve is characterized by the complexity of disassembling and assembling (if necessary, repair), requiring special devices, in particular, for removing the seat and when removing the locking member, which is difficult in the field. In the event of a valve failure, it must be removed from the trunk line for delivery to the repair base, which entails the need to shut off the pipeline for a long time and causes economic losses to the transporting company. And the deformation of the threaded joints in the fasteners of the seat and the inner body of the shut-off element makes the valve generally non-separable, and the repair requires special devices designed to cut off the deformed threaded fasteners of the valve body internals.

The aim of the invention is to increase the reliability of the valve design by ensuring stable tightness during the entire service life and simplifying the repair process.

This goal is achieved by the fact that in the valve with the axial direction of flow, containing the outer casing with inlet and outlet channels, in the inner cavity of which is rigidly fixed with the formation of an annular channel with a profile in the form of a Venturi nozzle, the inner cone-shaped casing, in which the shut-off mechanism is installed an organ with a working surface in the form of a part of a sphere in contact with a saddle made in the form of a ring with a contact conical surface that inscribes the saddle in the profile of the annular channel, wherein the movement mechanism is equipped with a compression spring mounted on a rod moving in sliding bearings mounted in a guide sleeve rigidly fixed in the inner case, and the saddle and inner case are installed in annular grooves, respectively made on the inner surfaces of the input and output channels of the outer case, according to the invention, the seat and the inner body are fixed on the surfaces of the grooves perpendicular to the longitudinal axis of the valve, and the fixation is made by threaded fasteners With the tapes, in addition, between the seat and its fixation surface there is a seal made of a material having elastic deformation, for example, graphite-containing material, for example, graphlex, and the guide sleeve is provided with a union nut, in the annular groove of which is made in the end part, a scraper is installed in the form of a ring of elastic material in contact with the surface of the rod.

Placing a saddle in an annular groove in the inlet channel of the outer casing and fixing it on the groove surface perpendicular to the longitudinal axis of the valve provides the possibility of unloading this assembly during impacts of a locking member, since the impact is perceived by the end surface of the annular groove belonging to the outer casing. The threaded fasteners in the saddle mount in the annular groove are not exposed to lateral impact loads and are not weakened during operation of the valve, which ensures a stable position of its internal components and increases the reliability of the valve.

The fastening of the seat and the inner casing with threaded fasteners uniformly distributed around the circumference on the surfaces of the annular grooves perpendicular to the longitudinal axis of the valve provides removability of the seat and the inner valve body, since threaded fastening of internals on the end surfaces of the annular grooves facilitates their removal for repair. When carrying out maintenance or repair in the field, serviceable internal units can be installed in the outer casing, which will reduce the time for disconnecting the line.

The use of a material with elastic deformation properties, for example, graphite-containing materials, in particular graphlex, for a seal installed between the seat and its fixing surface, for example, allows not only to calculate the exact initial seal shape necessary and sufficient to ensure valve tightness at high pressures, but also ensures the preservation of the desired shape and seal properties throughout the life of the valve.

The supply of the guide sleeve with a union nut, which ensures the stability of the assembly of the bearing assemblies and prevents impurities from entering the working medium flow, and the installation of a scraper in the form of an elastic material ring in the annular groove of the nut made in the end part in contact with the stem surface prevents pollution the surface of the rod, eliminates sticking and jamming of the locking body, which increases the reliability of the valve.

In Fig.1 shows the described valve with an axial direction of flow in section.

Figure 2 presents the remote element R.

Figure 3 - remote element C.

Figure 4 shows the remote element T.

The valve comprises an outer housing 1 with inlet A and outlet B channels. In the inner cavity of the outer casing there are installed inner bodies, represented by the inner casing 2, which forms an annular channel B for passage of the working medium, and an annular seat 3. In the cavity G of the inner casing, a locking member 4 is installed with a working surface as part of a sphere. The locking mechanism for moving the locking member comprises a rod 5 mounted in sliding bearings 6 and an intermediate sleeve 7, fixed with a union nut 8 and a lock nut 9 in the guide element D, which is part of the housing 2 (figure 3). The locking element 4 is pressed by a spring 10 to the saddle 3, mounted in an annular groove 11, made at the boundary of the input channel. The saddle is fixed on the surface 12 of the annular groove by means of threaded elements 13 uniformly distributed around the circumference. Between the saddle and the surface 12 there is a seal 14 made in the form of a flat graphlex ring.

In the annular groove E of the union nut, made in its end part, there is a scraper 15 in the form of a ring of elastic material and a damping ring 16 fixed by a washer 17 (in FIGS. 2 and 4).

In the rear part of the inner case, a discharge chamber Ж is made, connected by a throttle channel I and cavity G.

The position of the inner casing in the cavity of the outer casing 1 is determined by an annular groove K and fixed by threaded fasteners 18 on the end surface of the annular groove perpendicular to the longitudinal axis of the valve. The surface L of the inner case, which is the “supporting” for the locking member, is supplemented by a cylindrical groove M, and the locking member is provided with a guide ring N.

The valve is shown closed when the flow direction is in the direction of the arrow. With the spring 10, the locking element 4 is pressed against the seat 3, closing the inlet channel A. In this case, the stem 5 is in the extreme right position. When the pressure of the medium increases and the hydrodynamic forces of the flow exceed the spring force, the shut-off body moves away from the surface of the seat 3, opening the passage of the working medium to the annular channel B and compressing the spring 10. The compression force of the spring is determined by the working pressure in the working medium flow and is determined by the selection of the spring. The rod 5 moves in the bearings 6, while creating in the unloading chamber W increased pressure. The surface of the rod during this movement is cleaned of admixture particles adhering to it by a scraper 15, equipped with a damping ring 16, fixed by a washer 17 in the annular groove E, made in the end part of the union nut 8. The pressure from the unloading chamber Ж through the channel And is discharged into the cavity Г and exerts counteracting the compression force of the spring, which prevents shock when the locking member approaches the end surface L of the inner housing 2. Thanks to the guide ring M, the locking member is installed in the cylindrical groove H inside rennego housing and the valve opens, providing a working fluid passage. This valve position is operational.

With increasing pressure in the line or an adjustable object (not shown in the drawing), at the moment of excess of pressure (with the direction of flow in the direction of arrow P) in the output channel B over the pressure in the input channel A, the effect of hydraulic forces on the shut-off element 4 is excluded, and under the action spring 10, it is pressed against the saddle 3, fixed on the surface 12 of the annular groove with threaded fasteners 13. Graphlex ring seal 14 is pressed against the surface 12 of the annular groove by the force of the threaded fasteners 13, transmitted saddle surface. This provides the necessary tightness of the seat. The valve is hermetically closed, preventing the flow of the transported medium from moving in the opposite direction.

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.

In addition, graphite-containing seals are heat and cold resistant and extend the temperature range of valve use.

Thanks to the threaded fastening in the cavity of the outer casing of the main valve elements, their removal and repair is facilitated, and the recovery of the product is accelerated by replacing its internal elements.

Sources of information

1. RF patent 1838702, cl. F 16 K 15/02, 08/30/1993.

2. German application 3610965 A1, cl. F 16 K 15/02, 08/10/1987.

3. The brochure of the company “Mokveld” “Check valves”.

4. US patent 5921276 A, cl. F 16K 15/06, 07/13/1999.

Claims (2)

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 rigidly fixed, with the formation of an annular channel with a profile in the form of a Venturi nozzle, an inner cone-shaped casing, in which, through the movement mechanism, a shut-off element with a working surface in the form of a part of the sphere in contact with the saddle, made in the form of a ring with a contact conical surface, inscribing the saddle in the profile of the annular channel, while the movement mechanism is equipped with a compression spring mounted on a rod moving in sliding bearings installed in a guide sleeve rigidly fixed in the inner housing, and the saddle and inner housing are installed in annular grooves, respectively made on the inner surfaces of the input and output channels of the outer housing, characterized in that the saddle and the inner body are fixed on the surfaces of the grooves perpendicular to the longitudinal axis of the valve, and the fixation is made by threaded fasteners, in addition, between the seat and In order to fix it, a seal is made, made of a material with elastic deformation, for example, graphite-containing material, and the guide sleeve is provided with a cap nut, in the annular groove of which is made in the end part, a scraper is installed in the form of a ring of elastic material in contact with the surface of the rod. 2. The check valve with the axial direction of flow according to claim 1, characterized in that, for example, graphlex is used as the seal material installed between the seat and its fixation surface.

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