RU2787087C1 - Gate valve assembly - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to the field of mechanical engineering, in particular to shut-off valves used to shut off the flow of liquid, gaseous abrasive and corrosive media, and can be used as gate valves. Protective elements made of elastomeric material are mounted in the gate valve assembly on the end surface of the seats coaxially installed in the valve body, from the side of contact with the gate valve, as well as on the back side. Due to their elastic properties and geometric dimensions, the protective elements are in constant contact with the seat, the sealing surface of the gate and the protective insert. The specified location of the protective elements and the presence of constant contact between the parts of the valve assembly (insert, gate, seats) makes it possible to prevent the ingress of mechanical impurities into the gaps formed during operation between the specified parts and prevent damage to the sealing elements of the seat and jamming of the seats. To protect the seats in the body for the installation of seats against corrosion and deformation, a protective insert with a nickel or chromium corrosion-resistant coating is used in the valve assembly, installed between the seat and the body. The insert compensates for body deformations due to the increased clearance between its outer diameter and the seat in the body, and the presence of a corrosion-resistant nickel or chromium coating prevents corrosion in the seat-to-body seal and seat jamming in the seat.

EFFECT: invention is aimed at ensuring the protection of the sealing elements of the seat and the insert of the slide gate valve from mechanical impurities contained in the transported medium, due to the optimal arrangement of the protective elements included in the design.

1 cl, 3 dwg

Description

The invention relates to the field of mechanical engineering, in particular to shut-off valves used to shut off the flow of liquid, gaseous, abrasive and corrosive media and can be used as a gate valve assembly.

The gate valve refers to a typical pipeline fitting with a locking element that moves back and forth, perpendicular to the direction of the working flow. It is used to block the flow of the working medium and to ensure the required level of tightness of the system. The gate valve assembly consists of seats coaxially installed in the valve body, equipped with sealing elements and a gate valve installed between the seats, with parallel sealing surfaces and a through hole.

When analyzing the prior art, technical solutions for gate valve assemblies were identified, in which the sealing of the “gate-seat” connection is ensured by installing sealing elements made of thermoplastic or elastomeric material in the saddles.

To prevent metal-to-metal contact, these sealing elements protrude a certain amount relative to the metal of the seat, thus forming a gap between the seat body and the gate.

Mechanical impurities and other contaminants that are in the working environment, passing through the flow section of the valve body during operation, enter the specified gap and damage the sealing elements of the seat and the sealing surfaces of the gate.

Some well-known technical solutions for gate valve assemblies provide protection from mechanical impurities in the form of installing scrapers in front of the end sealing elements of the seat, but this solution does not completely eliminate the problem, since the known materials of the scrapers and their geometric dimensions do not exclude the appearance of the above gap, as well as the gap between the end face. of the scraper and the sealing surface of the gate, since the sealing elements of the seat are primarily in contact with the gate, and only when the seat is additionally pressed against the gate by the pressure of the working medium, the gap between the end face of the scraper and the sealing surface of the gate is leveled.

The same problem, damage to the sealing elements of the seat and the sealing surfaces of the gate, occurs when mechanical impurities and other contaminants enter the gap between the seat and the gate, located in the internal cavity of the body (gate space). In practice, the protection of sealing elements from these effects of mechanical impurities is not provided.

Slide gate valve seats are movable - they have the ability to move along the axis of the valve body through pipes when creating a pressure drop across the gate in the closed position (shut off the flow of the working medium). At the same time, a significant gap is formed between the rear surface of the seats and the end face of the seat in the valve body. Mechanical impurities and other contaminants that are in the working environment also get into this gap, thereby preventing the free movement of the seats, and contributing to the jamming of the seats in the seats of the valve body.

Seats in the body of a sliding gate valve for the installation of seats during operation are subject to corrosion (if the body of the valve is not made of corrosion-resistant steel), as a result, there is a loss of tightness of the seat-to-body seal, and the appearance of pitting corrosion on the seats entails followed by jamming of the seats and, consequently, loss of tightness of the seat-gate seal.

Under the influence of loads (bending moments, axial forces) transferred to the body of the slide gate valve by pipelines connected to it, the seats in the body of the gate valve for the installation of seats are subject to deformation, which leads to a decrease in the gap between the outer diameter of the seat and the inner diameter of the seat and, in eventually jammed seats.

So known is the sealing system for industrial shut-off valves, described in the patent for invention No. 2570995, published on 12/20/2015. The seat contains two annular sealing elements on the end surface facing the gate, one is made of thermoplastic material and has a polygonal cross section, the second is made of elastomer and has a round or triangular cross section. The disadvantages of the known design of the valve sealing system are as follows. The design does not exclude tearing out of the seat of the sealing elements made of elastomer and displacement of the thermoplastic seal under the influence of pressure and high-speed flow of the transported medium, especially when seals are placed together, as well as at low operating temperatures.

Also known gate valve, containing a housing with a through hole, inlet and outlet nozzles installed in it with a shut-off body in the form of a gate with a hole, movable seats with a sealing element and independent support sleeves, each of which is fixed inside the housing, the sealing element on the side facing to the gate, made along the radius (Patent RU No. 2128308 C1, IPC F16K 3/20, dated 03/25/1997, publ. 03/27/1999).

The disadvantage of the gate valve is that the movable seats with the sealing element are located in direct contact with the working medium, which leads to premature wear of the sealing element, since all mechanical impurities of the working medium are perceived by this element, resulting in a decrease in tightness and reliability during operation of the valve.

A gate valve assembly is known (PM RF, 125664, F16K3/06, publ. 03/10/2013), containing a gate interacting on both sides with sealing fields of coaxial seats made in the form of stepped bushings placed in reciprocal concentric bores of the nozzles, and the smaller stage of the seats is sealed relative to the latter, and the ends of the nozzles interact with the elastic elements installed in the blind holes of the larger stage of the saddles, and the elastic elements are made in the form of cylindrical columns made of an elastomeric material, for example, polyurethane, and the elastic elements are made in the form of cylindrical tubes.

The closest technical solution, selected as a prototype, is a slide gate valve, described in the patent for the invention of the Russian Federation, No. 2594450, F16K3/02, publ. 08/20/2016 In the gate of a gate valve having a flat gate with a through hole, seats located coaxially with the through hole of the branch pipes, equipped with sealing and supporting elements, in accordance with the technical solution, the sealing element is a combined seal, including a fixed radial sealing element and a sealing element located in front of it from the side of the passage, which provides a cleaning function, and the seat is made collapsible with a rigid seal (in the lock) of the sealing and supporting elements.

The design of the seat is complicated by the presence of a pressure ring and a spaced support bearing.

The objective of this technical solution is to increase the level of reliability of the gate valve assembly:

- in terms of protection against the impact of mechanical impurities and other contaminants contained in the working environment;

- in terms of protecting the seats in the body for the installation of seats from corrosion and deformation arising as a result of loads transferred to the body of the sliding gate valve by pipelines connected to it.

The technical result achieved by using the claimed invention is to ensure the protection of the sealing elements of the seat and the insert of the slide gate valve from mechanical impurities contained in the transported medium due to the optimal arrangement of the protective elements included in the design.

The technical result is achieved by the fact that in the known gate valve assembly, on the end surface of the seats coaxially installed in the valve body, from the side of contact with the gate valve, as well as on the back side, protective elements made of elastomeric material are mounted. Due to their elastic properties and geometric dimensions, the protective elements are in constant contact with the seat, the sealing surface of the gate and the protective insert. The specified location of the protective elements and the presence of constant contact between the parts of the valve assembly (insert, gate, seats) makes it possible to prevent the ingress of mechanical impurities into the gaps formed during operation between the specified parts and prevent damage to the sealing elements of the seat and jamming of the seats. To protect the seats in the body for the installation of seats from corrosion and deformation, a protective insert with a nickel or chromium corrosion-resistant coating is used in the valve assembly, installed between the seat and the body. The insert compensates for body deformations due to the increased gap between its outer diameter and the seat in the body, and the presence of a corrosion-resistant nickel or chromium coating prevents corrosion in the seat-to-body seal and seat jamming in the seat.

The claimed invention is illustrated by the following illustrations:

Fig. 1 - shows a general view of the slide gate valve assembly;

Fig. 2 - shows the gate valve assembly with protective elements;

Fig. 3 - the saddle of the gate valve assembly is shown, where the following positions are indicated:

1. Housing

2. Shiber

3. Insert

4. Saddle

5. Protective element

6. Insert end seal

7. Spring

8. Radial sealing element of the insert

9. Radial seat seal

10. Protective element

11. Seat end seal

12. Protective element

13. Through hole

14. Pass pipes

15. Body cavity (gate space)

16. Groove of the protective element (outer)

17. Groove of the protective element (internal)

The gate valve assembly consists of two seats (4) based in inserts (3) installed coaxially in the seats of the valve body (1). Between the saddles (4) there is a gate (2) having parallel sealing surfaces and a through hole (13) located in the upper part. The seats (4) and gate (2) are able to move along the axis of the passage pipes (14) of the valve body (1) to ensure automatic relief of excess pressure from the cavity (gate space) (15) of the valve body (1) into the passage pipe (14) with working pressure. The gate (2) has the ability to move in the vertical direction to block the flow of the working medium by transmitting reciprocating motion from the control unit (not shown in Figure 1). Inserts (3) have a protective corrosion-resistant nickel or chrome coating to prevent corrosion in the seat-insert seal. On the rear surface and along the outer diameter of the insert (3) there are sealing elements (6) and (8) made of elastomeric materials, which ensure tightness in the "insert-body" seal. The seats (4) have end (11) and radial (9) sealing elements, which ensure tightness in the "seat-gate" and "seat-insert" seals, respectively. Protective elements (10), (12) and (5) made of elastomeric material, preventing the ingress of mechanical impurities and other contaminants into the gaps between the seats (4), gate (2) and inserts (3). The seats (4) are pressed against the gate (2) by the force of the springs (7).

In the claimed invention, to eliminate the shortcomings of the known technical solutions of gate valve assemblies, in terms of damage to the sealing elements (11) of the seat (4) and the sealing surfaces of the gate (2) in the presence of mechanical impurities in the working medium, as well as jamming of the seats (4) when exposed to on seats in the body of pitting corrosion, deformation and mechanical impurities, the seat (4) of the gate valve has two protective elements (10) and (12) located on the end surface of the seats (4), from the side of contact with the gate (2). Protective elements (10) and (12) are made of elastomeric material and have geometric parameters that allow constant contact with the sealing surface of the gate, even when the seats (4) are moved in the seats along the axis of the passage pipes (14) of the body (1), which allows have practically no effect on the values of the specific pressure in the sealing elements (11), which is necessary to ensure the tightness of the gate-seat seal, and protects the sealing elements (11) of the seat (4) and the sealing surfaces of the gate (2) from damage arising from exposure to mechanical impurities and other contaminants in the working environment. Protective elements (10) and (12) prevent the ingress of mechanical impurities into the gap between the seats (4) and the gate (2) both from the side of the passage pipes (14) and from the side of the internal cavity (15) of the body (1), thereby significantly increasing the level of reliability of the shutter assembly. The protective elements (10) and (12) have grooves (16) and (17) designed for the flow of the working medium and preventing the elements from being pulled out of their seats when the gate (2) is moved from the “closed” position to the “open” position. Inserts (3) are installed between the seats (4) and seats in the body (1) of the gate valve, which have a protective corrosion-resistant nickel or chrome coating that prevents corrosion in the seat-insert seal, which eliminates jamming of the seats (4) in the seat and reduces the risk of loss of tightness of the specified seal. The increased gap between the outer diameter of the insert (3) and the seat in the body (1) compensates for deformations that occur when exposed to loads (bending moments, axial forces) transferred to the body (1) of the sliding gate valve by pipelines attached to it and makes it possible to exclude deformation of the seats under the seats (4) in the inserts (3), and, consequently, the jamming of the seats (4). Protective elements (5) are installed between the rear surface of the seats (4) and the end surfaces of the seat of the inserts (3), which prevent mechanical impurities from entering the gap between the seats (4) and inserts (3). Protective elements (5) are made of elastomer material and have geometric parameters that allow constant contact with the rear surface of the seats (4) and the end surfaces of the seat of the inserts (3), even when the seats (4) move in the seats along the axis of the body through pipes ( 1). Seats for seats (4) in inserts (3) are protected from mechanical impurities and, therefore, the risk of seat jamming and loss of tightness of the valve assembly is excluded.

The gate valve works as follows.

In the initial position, when the valve is open, the through hole (13) of the gate (2) is aligned with the flow area of the branch pipes (14) of the housing (1) and the flow of the working medium passes through the valve.

When the valve is closed, the gate (2) moves in the vertical direction by transmitting reciprocating motion from the control unit and closes the flow area of the branch pipes (14) of the body (1).

The tightness of the gate is ensured by two seats (4) and a gate (2), constantly pressed against each other:

- "inlet" seat (on the side of pressure supply) - hermetically sealed due to the radial seal (9) mounted on the outer diameter of the seat, as well as due to the pressure against the gate by the force of the springs (7) installed on the rear side of the seat, and the pressure of the working medium (before shutter);

- the “outlet” seat is also hermetic due to the radial seal (9) and the gate valve (2) being pressed against it by the pressure difference between the inlet and outlet pipes (14) of the valve body (1). The “outlet” seat ensures reliable tightness of the valve in case of violation of the density of the “inlet” seat.

With the gate valve open and closed, all gaps between the gate (2), seats (4) and inserts (3) are closed by protective elements (10), (12) and (5), which contributes to the free passage of mechanical impurities and other contaminants through the valve, in the working environment. Mechanical impurities and other contaminants do not get into the gaps between the moving parts of the valve assembly and, consequently, do not damage the sealing elements (11) of the seats (4), and also do not prevent the free movement of the seats (4) in the seats of the insert (3).

Seats in inserts (3) for seats (4) are covered with nickel or chrome plating to prevent corrosion resulting from contact with the working medium and, consequently, jamming of seats (4).

Inserts (3), due to the increased gap between its outer diameter and the diameter of the seat in the body (1), compensate for deformations of the body (1) that occur when the valve is exposed to bending moments and axial forces from pipelines, which prevents jamming of the seats (4) and subsequent loss of seal tightness.

Thus, the implementation of the invention solves the problems set by the authors of ensuring the protection of the sealing elements of the seat and the insert of the slide gate valve from mechanical impurities contained in the transported medium due to the optimal arrangement of the elements included in the design and deformations resulting from the loads transferred to the body of the slide gate valve by the attached pipelines to it.

Claims (1)

Knife gate valve, including a flat gate with a through hole, seats installed coaxially with the through hole of the nozzles and equipped with sealing elements, characterized in that the saddles are equipped with annular inserts made of corrosion-resistant metal or metal with a corrosion-resistant coating, also provided with sealing elements , on the end surface of the seats, from the side of contact with the gate, protective elements made of elastic polyurethane are installed, made with the possibility of constant contact with the sealing surface of the gate and provided with grooves for the flow of the working medium and preventing them from being pulled out of their seats during the operation of the gate, in addition, protective elements made of polymeric material are installed on the rear surface of the saddles, from the side of the insert, with the possibility of constant contact with it.

Images