Ball valve

Abstract

This utility model relates to the design of ball valves, primarily cryogenic, and is aimed at increasing their reliability and service life. The utility model involves applying a polymer antifriction coating to the friction surfaces of the metal sealing inserts of the valve seats that contact the ball plug, as well as to the mating surface of the ball plug. The coating is a solid lubricant, such as MODENGY 1005, 0.5-1.0 mm thick, maintaining its properties over a wide temperature range (from -200°C to +255°C).

Description

[0001] Technical field

[0002] This utility model pertains to mechanical engineering, specifically to pipeline valves, and can be used in the design of ball valves intended for operation in cryogenic environments. Specifically, the utility model concerns a ball valve valve assembly, including seats with sealing elements.

[0003] Prior Art

[0004] Ball valve designs are known to include a body, a ball plug, seats with metal sealing inserts, and a stem for rotating the plug. These valves are widely used as shutoff valves.

[0005] The closest analogue of this utility model is the ball valve described in patent RU 124345 U1. The design includes a body, a ball plug, seats with metal sealing inserts, and a stem. When operating in the absence of lubrication and under increased contact stress, scoring, scratching, and other abrasive wear occur in the contact area between the ball plug and the metal seats, leading to a loss of seal, the need for frequent repairs and seat replacement, and shortened service intervals.

[0006] A technical problem for known solutions is the insufficient wear resistance of the sealing surfaces of seats and plugs of ball valves operating under dry friction conditions, especially in the cryogenic temperature range, which leads to a decrease in the reliability and service life of the product.

[0007] Disclosure of Utility Model

[0008] The technical result of the claimed utility model is to increase the service life of the shutter unit of a cryogenic ball valve by increasing the wear resistance of the sealing surfaces of the seat and plug, reducing scuffs and scratches on their mating surfaces, which ultimately extends the intervals between repairs and improves operational reliability.

[0009] The technical result is achieved by a ball valve containing a body, a ball plug, seats installed in the body with metal sealing inserts in contact with the surface of the ball plug, and a stem for rotating the plug.

[0010] The distinguishing feature of the utility model is that a polymer antifriction coating based on a solid lubricant is applied to the friction surfaces of the metal sealing inserts of the seats that contact the ball plug, as well as to the mating surface of the ball plug, the width of which exceeds by 1 mm to 2 mm the diameter of the metal sealing inserts of the seats, including film formers, solvents, highly dispersed particles of solid lubricants based on molybdenum disulfide and functional additives, with a thickness of 0.5 mm to 1.0 mm.

[0011] Justification of the achievement of the technical result

[0012] Due to the fact that a polymer antifriction coating based on a solid lubricant is applied to the rubbing surfaces of the metal sealing inserts of the seats that are in contact with the ball plug, as well as to the mating surface of the ball plug, whose width exceeds the diameter of the metal sealing inserts of the seats by 1 mm to 2 mm, which includes film formers, solvents, highly dispersed particles of solid lubricants based on molybdenum disulfide and functional additives, the coefficient of friction between the rubbing surfaces of the plug and seats is reduced, minimizing the friction forces during opening / closing, their wear resistance is increased due to the properties of the coating (good adhesion due to the content of film formers, high load-bearing capacity, abrasion resistance due to the presence of molybdenum disulfide and functional additives), which prevents the formation of scuffs and scratches,Maintains performance properties over a wide temperature range (from -200°C to +255°C), which is critical for cryogenic valves, compensating for the impossibility of using traditional lubricants under these operating conditions. Furthermore, the optimal coating thickness range (0.5-1.0 mm) ensures its integrity under these operating conditions, as thinner coatings lead to microcracks, while thicker coatings increase the risk of delamination.

[0013] At the same time, due to the fact that the polymer antifriction coating is applied to all the friction surfaces of the metal sealing inserts of the seats that are in contact with the ball plug, as well as to the mating surface of the ball plug, the width of which exceeds the diameter of the metal sealing inserts of the seats by 1 mm to 2 mm, the effective use of the coating and the achievement of the technical result are ensured, since the specified increase in the coating application area on the mating surface of the ball plug in the range from 1 mm to 2 mm makes it possible to compensate for temperature expansions and manufacturing errors of the ball valve elements, preventing friction on the metal, while a further increase in the width of the coating application area on the ball plug does not lead to a further increase in the wear resistance of the sealing surfaces of the seat and plug, and at a smaller value, guaranteed compensation for temperature expansions and manufacturing errors is not achieved, i.e.the technical result is no longer achieved.

[0014] Thus, the specified set of features of the proposed technical solution provides a cause-and-effect relationship with the declared technical result - a significant increase in the resource of the shutter unit.

[0015] Brief description of drawings

[0016] Fig. 1 - Isometry of a ball valve.

[0017] Fig. 2 - Longitudinal section of the ball valve showing the elements of the valve assembly.

[0018] Fig. 3 - Metal seat sealing insert.

[0019] Fig. 4 - Metal seat seal insert with applied polymer coating (view A in Fig. 3).

[0020] List of items:

[0021] 1 - Crane body

[0022] 2 - Ball plug

[0023] 3 - Metal Seat Insert

[0024] 4 - Rod

[0025] 5 - Area of ​​application of polymer antifriction coating on the ball plug (shown by the dashed line in Fig. 2)

[0026] 6 - Area of ​​application of polymer antifriction coating on the metal sealing insert of the seat (shown by the dashed line in Fig. 4)

[0027] Implementation of a utility model

[0028] The utility model is implemented as follows.

[0029] The cryogenic ball valve (Fig. 1) comprises a body 1 containing a ball plug 2 with a through hole. The plug 2 is pressed on both sides by seats, the sealing elements of which are made in the form of metal sealing inserts 3. Rotation of the plug 2 is transmitted from the actuator via a stem 4.

[0030] When the valve is closed, the ball plug 2 rotates, its spherical surface is tightly pressed against the surface of the metal sealing inserts 3 of the seats in the contact zone, ensuring the tight shut-off of the medium flow.

[0031] According to the utility model, a polymer antifriction coating is applied to the friction surfaces of the metal sealing inserts 3 of the seats facing the ball plug 2 (zone 6 in Fig. 3), as well as to the mating surface of the ball plug 2, the width of which exceeds by 1 mm to 2 mm the diameter of the metal sealing inserts 3 of the seats (zone 5 in Fig. 2). The polymer antifriction coating is a coating based on a solid lubricant, which includes film-forming agents, solvents, highly dispersed particles of solid lubricants based on molybdenum disulfide and functional additives, for example, solid lubricant MODENGY 1005, which has high wear resistance and a low friction coefficient in the temperature range from -200 °C to +255 °C. The coating is applied by spraying, covering areas where it should not be applied, followed by heat treatment (curing at 150°C for 30-60 minutes) to a thickness of 0.5 mm to 1.0 mm.

[0032] When the ball valve is in operation, the coating reduces friction in the contact area between the ball plug 2 and the metal sealing insert 3, prevents scoring and abrasive wear of the metal, thereby significantly increasing the service life of the seat, ball plug and the entire valve assembly of the cryogenic ball valve.

Claims

1. A ball valve comprising a body, a ball plug installed in the body, seats with metal sealing inserts in contact with the surface of the ball plug, and a stem for rotating the plug, characterized in that a polymer antifriction coating based on a solid lubricant is applied to the rubbing surfaces of the metal sealing inserts of the seats in contact with the ball plug, as well as to the mating surface of the ball plug, the width of which exceeds the diameter of the metal sealing inserts of the seats by 1 mm to 2 mm.

2. A ball valve according to paragraph 1, characterized in that the solid lubricant includes film formers, solvents, highly dispersed particles of solid lubricants based on molybdenum disulfide and functional additives.

3. A ball valve according to paragraph 1, characterized in that the thickness of the polymer antifriction coating is from 0.5 mm to 1.0 mm.

4. A ball valve according to paragraph 1, characterized in that the polymer antifriction coating is operational in the temperature range from -200°C to +255°C.

Images