A cryogenic and low-leakage high-pressure balanced control valve

Abstract

The present invention relates to an ultra-low temperature and low-leakage high-pressure balanced regulating valve, which includes a flanged upper sleeve, a lower sleeve, and a valve core; the valve core is fixedly connected to one end of a valve stem, and the other end of the valve stem passes through the upper valve cover and is connected to an actuator; an annular groove is formed on the upper end surface of the lower sleeve, and a guiding wedge-shaped retaining ring and a disc spring group are placed in the annular groove; a PCTFE wedge-shaped seal is sleeved on the outer wall of the valve core, and the wedge-shaped surface on the outer side of the PCTFE wedge-shaped seal abuts against the wedge-shaped surface of the guiding wedge-shaped retaining ring, so that the inner side of the PCTFE wedge-shaped seal is in close contact with the outer wall of the valve core for sealing; by arranging the PCTFE wedge-shaped seal outside the valve core, the upward supporting force of the disc spring group on the guiding wedge is converted into the force of the PCTFE wedge-shaped seal horizontally fitting against the valve core through the wedge-shaped surface, so that the valve core is always in close contact and sealed with the PCTFE wedge-shaped seal during the lifting process, solving the problem of large leakage of the balance seal ring in the ultra-low temperature environment.

Description

Technical Field

[0001] The present invention relates to a valve body, and more particularly to an ultra-low temperature and low-leakage high-pressure balanced control valve. Background Art

[0002] With the continuous expansion of the domestic LNG and air separation unit markets, the demand for cryogenic valves is increasing, and the requirements for the pressure rating of cryogenic valves are also higher. As a result, the problems of large internal and external leakage existing in traditional cryogenic high-pressure control valves have become more and more obvious and urgently need to be solved. Most of the cryogenic high-pressure valves used in China are imported. In the field of cryogenic industrial automation control in China, limited by the sealing performance and reliability of traditional single cryogenic balance seals, it is difficult to meet the requirements of users for ultra-low temperature, low leakage, and high pressure difference. This common phenomenon has greatly restricted the research and development of domestic ultra-low temperature high-pressure valves.

[0003] In summary, in order to meet the requirements of high pressure difference, low leakage, and ultra-low temperature, solving the problem of large leakage of domestic balance seals in ultra-low temperature environments has become an urgent problem for the researchers of the company. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the balance seal has a large leakage in an ultra-low temperature environment;

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention is an ultra-low temperature and low-leakage high-pressure balanced control valve, including an upper sleeve and a lower sleeve that are snap-connected to each other; through holes for the lifting of the valve core are formed in the upper sleeve and the lower sleeve in a penetrating manner; one end of the valve core is fixedly connected to one end of the valve stem, and the other end of the valve stem passes through the upper valve cover and is connected to the actuator; a ring groove is formed on the upper end surface of the lower sleeve, and a guiding wedge-shaped retaining ring and a disc spring group for supporting the guiding wedge-shaped retaining ring are placed in the ring groove; a PCTFE wedge-shaped seal is sleeved on the outer wall of the valve core, and the wedge surface on the outer side of the PCTFE wedge-shaped seal abuts against the wedge surface of the guiding wedge-shaped retaining ring, and the inner side of the PCTFE wedge-shaped seal is attached to and sealed with the outer wall of the valve core;

[0007] The traditional single cryogenic high-pressure balance seal deforms at ultra-low temperatures, resulting in the leakage of the medium from the balance seal. The present invention adopts a wedge-shaped seal made of PCTFE, which is not easily deformed at low temperatures; a ring groove is formed on the lower sleeve, and a disc spring group is arranged in the ring groove. The disc spring group is used to support the guiding wedge-shaped retaining ring. The wedge surface on one side of the guiding wedge-shaped retaining ring cooperates with the wedge surface on one side of the PCTFE wedge-shaped seal, and the upward supporting force of the disc spring group on the guiding wedge is converted into a force for the PCTFE wedge-shaped seal to horizontally adhere to the valve core through the wedge surface, so that the valve core is always in close contact and sealed with the PCTFE wedge-shaped seal during the lifting process.

[0008] To ensure that the supporting force of the disc spring group acting on the guiding wedge-shaped retaining ring remains consistent, the present invention adopts a limiting ring that extends downward from the guiding wedge-shaped retaining ring. The limiting ring is placed in the annular groove, and a disc spring group is sleeved on the limiting ring.

[0009] The limiting ring makes the guiding wedge-shaped retaining ring concentric with the valve core. The limiting ring is also restricted by the disc spring group and can only move up and down, thereby ensuring that the force acting on the PCTFE wedge-shaped seal is equal everywhere, and thus ensuring the coaxiality of the movement of the valve core.

[0010] To prevent rainwater and condensed water from entering the thermal insulation layer, the present invention adopts at least one drip plate horizontally welded to the outer wall of the upper valve cover.

[0011] The drip plate can not only prevent rainwater and condensed water from entering the thermal insulation layer, but also alleviate the upward transfer of the valve body temperature. Through theoretical research and experimental verification, the present invention welds two drip plates on the upper valve cover, which can effectively reduce the extended length of the upper valve cover. There are two advantages: one is to reduce the extended length of the upper valve cover, reduce the material consumption, and always keep the temperature at the packing above 0°C; the other is to reduce the length of the upper valve cover, the length of the valve stem is also correspondingly shortened, and the deflection of the valve stem deformation is correspondingly reduced, ensuring excellent coaxiality between the valve core and the valve stem, so as to achieve the goal of low leakage of the valve.

[0012] To ensure the seal between the valve stem and the upper valve cover, the present invention adopts a packing bottom pad arranged at the gap between the valve stem and the upper valve cover. An O-ring is arranged outside the packing bottom pad to fit with the inner wall of the upper valve cover; a valve stem seal ring is arranged inside the packing bottom pad to fit with the outer wall of the valve stem; a packing flat pad is arranged at the bottom of the packing bottom pad to prevent the valve stem seal ring from deforming and getting stuck in the gap between the valve stem and the upper valve cover.

[0013] The traditional seal at the stuffing box only prevents the leakage of the medium by compressing the packing. This not only requires high quality of the packing, but also greatly increases the frictional force of the valve stem after excessive compression of the packing. To solve this problem, by adding a valve stem balance seal ring to the inner hole of the packing bottom pad and installing an O-ring on the outer edge of the packing bottom pad, the frictional force of the valve stem is effectively reduced, realizing the characteristic of slight internal and external leakage at the stuffing box, and greatly improving the reliability and safety of the valve; in summary, O-rings and valve stem seal rings are respectively arranged on the inner and outer sides of the packing bottom pad, so as to achieve double internal and external seals for the medium flowing into the gap between the valve stem and the upper valve cover; to prevent the valve stem seal ring from deforming and getting stuck in the gap between the valve stem and the upper valve cover, the present invention installs a packing flat pad on the packing bottom pad, and the packing flat pad will not deform during the movement of the valve stem, so as to prevent the valve stem seal ring from getting stuck in the gap between the valve stem and the upper valve cover; in addition,

[0014] To illustrate the connection relationships among the valve body, the upper valve cover, the upper sleeve, and the lower sleeve, in the present invention, the upper valve cover is fixedly connected to the valve body. An annular lug is provided at the top of the upper sleeve, and sealing gaskets are provided on both the upper and lower end faces of the lug, and it is snap-connected to the connection part between the upper valve cover and the valve body; a notch is provided at the bottom of the lower sleeve, and a boss for supporting the notch is provided in the middle of the valve body.

[0015] In the present invention, bolts and nuts are used to connect the upper valve cover and the valve body. In addition, an ear is provided at the top of the upper sleeve, and a sealing gasket is provided on the ear and it is snap-connected to the connection part between the upper valve cover and the valve body to prevent the medium from leaking from the connection part between the upper valve cover and the valve body.

[0016] In summary, the boss of the valve body is used to support the lower sleeve, the upper and lower sleeves are snap-connected to each other, and the upper sleeve is connected to the upper valve cover and the valve body through the ear, realizing the connection among the valve body, the upper valve cover, the upper sleeve, and the lower sleeve.

[0017] The beneficial effects of the present invention: The present invention is a cryogenic low-leakage high-pressure balanced control valve. By providing a PCTFE wedge-shaped seal outside the valve core and a guiding wedge-shaped retaining ring that abuts against the PCTFE wedge-shaped seal, the supporting force of the disc spring group on the guiding wedge-shaped retaining ring upward is converted into the force for the PCTFE wedge-shaped seal to horizontally fit the valve core through the wedge surface, so that the valve core is always in sealing fit with the PCTFE wedge-shaped seal during the lifting process, solving the problem of large leakage of the balance sealing ring in the cryogenic environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the drawings and embodiments.

[0019] Figure 1 is the structural schematic diagram of the present invention;

[0020] Figure 2 is Figure 1 the enlarged view of part II;

[0021] Figure 3 is Figure 1 the enlarged view of part I;

[0022] Figure 4 is Figure 1 the enlarged view of part III;

[0023] In the figure: 1 - upper sleeve, 2 - lower sleeve, 3 - valve core, 4 - valve stem, 5 - upper valve cover, 6 - annular groove, 7 - guiding wedge-shaped retaining ring, 8 - disc spring group, 9 - PCTFE wedge-shaped seal, 10 - limiting ring, 11 - drip plate, 12 - packing bottom gasket, 13 - O-ring, 14 - valve stem seal ring, 15 - packing flat gasket, 16 - valve body, 17 - annular lug, 18 - notch. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, and therefore only showing the components related to the present invention.

[0025] As Figure 1-2 shown, the present invention is a cryogenic low-leakage high-pressure balanced control valve, including an upper sleeve 1 and a lower sleeve 2 that are snap-connected to each other; through holes for the lifting of the valve core 3 are formed through the upper sleeve 1 and the lower sleeve 2; one end of the valve core 3 is fixedly connected to one end of the valve stem 4, and the other end of the valve stem 4 passes through the upper valve cover 5 and is connected to the actuator; an annular groove 6 is formed on the upper end surface of the lower sleeve 2, and a guiding wedge-shaped retaining ring 7 and a disc spring group 8 for supporting the guiding wedge-shaped retaining ring 7 are placed in the annular groove 6; a PCTFE wedge-shaped seal 9 is sleeved on the outer wall of the valve core 3, and the wedge surface on the outer side of the PCTFE wedge-shaped seal 9 abuts against the wedge surface of the guiding wedge-shaped retaining ring 7, and the inner side of the PCTFE wedge-shaped seal 9 is attached to and sealed with the outer wall of the valve core 3;

[0026] The traditional single cryogenic high-pressure balanced sealing ring deforms at ultra-low temperatures, resulting in leakage of the medium from the balanced sealing ring. The present invention adopts a wedge-shaped seal made of PCTFE, which is not easily deformed at low temperatures; an annular groove is formed on the lower sleeve, and a disc spring group is arranged in the annular groove. The disc spring group is used to support the guiding wedge-shaped retaining ring. The wedge surface on one side of the guiding wedge-shaped retaining ring cooperates with the wedge surface on one side of the PCTFE wedge-shaped seal, and the upward supporting force of the disc spring group on the guiding wedge is converted into a force for the PCTFE wedge-shaped seal to horizontally adhere to the valve core through the wedge surface, so that the valve core and the PCTFE wedge-shaped seal are always adhered and sealed during the lifting process.

[0027] As Figure 2 shown, in order to ensure that the supporting force of the disc spring group acting on the guiding wedge-shaped retaining ring remains consistent, the present invention adopts a limiting ring 10 that extends downward from the guiding wedge-shaped retaining ring 8. The limiting ring 10 is placed in the annular groove 6, and a disc spring group 7 is sleeved on the limiting ring 10;

[0028] The limiting ring makes the guiding wedge-shaped retaining ring and the valve core concentrically arranged. The limiting ring is also restricted by the disc spring group and can only move up and down, so as to ensure that the force acting on the PCTFE wedge-shaped seal is equal everywhere, thereby ensuring the coaxiality of the movement of the valve core.

[0029] As Figure 1 shown, in order to prevent rainwater and condensate from entering the thermal insulation layer, the present invention adopts at least one drip plate 11 horizontally welded to the outer wall of the upper valve cover 5;

[0030] The drip plate can not only prevent rainwater and condensate from entering the insulation layer, but also relieve the upward transfer of the valve body temperature. Through theoretical research and experimental verification, two drip plates are welded on the upper valve cover in the present invention, which can effectively reduce the extended length of the upper valve cover. There are two advantages: firstly, reducing the extended length of the upper valve cover reduces the material consumption and always keeps the temperature at the packing above 0°C; secondly, reducing the length of the upper valve cover also correspondingly shortens the length of the valve stem, and the deflection of the valve stem deformation is correspondingly reduced, ensuring excellent coaxiality between the valve core and the valve stem, so as to achieve the goal of low leakage of the valve.

[0031] As Figure 3 shown, in order to ensure the seal between the valve stem and the upper valve cover, the present invention adopts a packing bottom pad 12 arranged at the gap between the valve stem 4 and the upper valve cover 5, and an O-ring 13 is arranged outside the packing bottom pad 12 to fit with the inner wall of the upper valve cover 5; a valve stem sealing ring 14 is arranged inside the packing bottom pad 12 to fit with the outer wall of the valve stem 4; a packing flat pad 15 for preventing the valve stem sealing ring 14 from deforming and getting stuck in the gap between the valve stem 4 and the upper valve cover 5 is arranged at the bottom of the packing bottom pad 12.

[0032] The traditional seal at the packing gland only prevents the external leakage of the medium by compressing the packing. This not only requires high quality of the packing, but also greatly increases the friction force of the valve stem after excessive compression of the packing. To solve this problem, a valve stem balance sealing ring is added to the inner hole of the packing bottom pad, and an O-ring is installed on the outer edge of the packing bottom pad, effectively reducing the friction force of the valve stem and realizing the characteristics of micro-leakage inside and outside the packing gland, greatly improving the reliability and safety of the valve; In summary, O-rings and valve stem sealing rings are respectively arranged on the inner and outer sides of the packing bottom pad, so as to achieve double sealing of the medium flowing into the gap between the valve stem and the upper valve cover; In order to prevent the valve stem sealing ring from deforming and getting stuck in the gap between the valve stem and the upper valve cover, the present invention is equipped with a packing flat pad on the packing bottom pad, and the packing flat pad will not deform during the movement of the valve stem, so as to prevent the valve stem sealing ring from getting stuck in the gap between the valve stem and the upper valve cover; In addition,

[0033] As Figure 4 shown, in order to illustrate the connection relationship between the valve body, the upper valve cover, the upper sleeve and the lower sleeve, the present invention adopts the upper valve cover 5 fixedly connected to the valve body 16. An annular ear 17 is arranged at the top of the upper sleeve 1, and sealing gaskets 18 are arranged on both the upper and lower end faces of the ear 17 and are clamped at the connection between the upper valve cover 5 and the valve body 16; a notch 18 is arranged at the bottom of the lower sleeve 2, and a boss for supporting the notch 18 is arranged in the middle of the valve body 1.

[0034] In the present invention, the upper valve cover and the valve body are connected by bolts and nuts. In addition, an ear is arranged at the top of the upper sleeve, and a sealing gasket is arranged on the ear and is clamped at the connection between the upper valve cover and the valve body to prevent the medium from leaking from the connection between the upper valve cover and the valve body;

[0035] In summary, the boss of the valve body is used to support the lower sleeve. The upper and lower sleeves are engaged with each other. The upper sleeve is connected to the upper valve cover and the valve body through the lug, realizing the connection of the valve body, the upper valve cover, the upper sleeve and the lower sleeve.

[0036] The present invention is a cryogenic low-leakage high-pressure balanced control valve. By arranging a PCTFE wedge-shaped seal outside the valve core and a guiding wedge-shaped retaining ring against the PCTFE wedge-shaped seal, the supporting force of the disc spring group on the guiding wedge upward is converted into the force of the PCTFE wedge-shaped seal fitting the valve core horizontally through the wedge surface, so that the valve core is always in sealing contact with the PCTFE wedge-shaped seal during the lifting process, solving the problem of large leakage of the balance sealing ring in the cryogenic environment.

[0037] Inspired by the above ideal embodiments of the present invention, through the above description, relevant staff can make various changes and modifications within the scope not deviating from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A cryogenic and low-leakage high-pressure balanced control valve, characterized in that: It includes a flange-type upper sleeve, a lower sleeve, and a valve core; One end of the valve core is fixedly connected to one end of the valve stem, and the other end of the valve stem passes through the upper valve cover and is connected to the actuator; An annular groove is formed on the upper end surface of the lower sleeve, and a guiding wedge-shaped retaining ring and a disc spring group for supporting the guiding wedge-shaped retaining ring are placed in the annular groove; A PCTFE wedge-shaped seal is sleeved on the outer wall of the valve core, and the wedge surface on the outer side of the PCTFE wedge-shaped seal abuts against the wedge surface of the guiding wedge-shaped retaining ring, so that the inner side of the PCTFE wedge-shaped seal is in close contact with the outer wall of the valve core for sealing; A limiting ring extending downward is provided on the guiding wedge-shaped retaining ring, the limiting ring is placed in the annular groove, and the disc spring group is sleeved on the limiting ring, and the limiting ring makes the guiding wedge-shaped retaining ring concentric with the valve core.

2. The cryogenic low-leakage high-pressure balanced control valve according to claim 1, characterized in that: At least one drip plate is horizontally welded on the outer wall of the upper valve cover.

3. The cryogenic low-leakage high-pressure balanced control valve according to claim 1, wherein: A packing bottom pad is arranged at the gap between the valve stem and the upper valve cover, and an O-ring is arranged outside the packing bottom pad and fits with the inner wall of the upper valve cover; a valve stem seal ring is arranged inside the packing bottom pad and fits with the outer wall of the valve stem; A packing flat pad for preventing the valve stem seal ring from deforming and being stuck in the gap between the valve stem and the upper valve cover is arranged at the bottom of the packing bottom pad.

4. The cryogenic low-leakage high-pressure balanced control valve according to claim 1, wherein: The upper valve cover is fixedly connected to the valve body, an annular lug is arranged at the top of the upper sleeve, and sealing gaskets are arranged on both the upper and lower end faces of the lug, and the lug is clamped at the connection between the upper valve cover and the valve body; A notch is arranged at the bottom of the lower sleeve, and a boss for supporting the notch is arranged in the middle of the valve body.

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