Ultralow-temperature gate valve and using method

Abstract

The invention discloses an ultralow-temperature gate valve and a using method, the gate valve comprises a valve body, a first cover plate and a valve rod, a closed cavity is formed in the first cover plate, and the cavity is connected with a middle cavity through a third through hole; the sealing component is installed between the first cover plate and the valve rod, the pressure relief component comprises a pressing block and a first bag body, the pressing block is located in the cavity and used for opening and closing the third through hole, and the first bag body is connected with the cavity and can expand to act on the sealing component. When the pressure in the middle cavity reaches a certain degree, the third through hole is opened by the pressing block, so that the first bag body expands to act on the sealing part, on one hand, the pressure in the middle cavity can be properly relieved, and sealing performance reduction caused by too large pressure is avoided, and on the other hand, the contact force between the sealing part and the valve rod and between the sealing part and the first cover plate can be increased through expansion of the first bag body; the sealing effect is improved; and the expansion change of the first capsule body can be adjusted along with the pressure in the middle cavity, so that the applicability is higher.

Description

Technical Field

[0001] The present invention relates to the field of valve technology, and in particular to an ultra-low temperature gate valve and a use method thereof. Background Art

[0002] The gate valve drives the valve stem 30 up and down through the valve wheel, so that the valve plate at the lower end of the valve stem 30 is separated from and fitted with the sealing surface 20 in the valve body 10, thereby intercepting and conveying the fluid medium; the movement direction of the valve plate in the gate valve is perpendicular to the direction of the fluid, so that the medium does not change its movement direction when flowing through the valve. It has the advantages of small flow resistance, flexible medium flow direction, and small opening and closing torque. It is widely used in pipeline systems in various fields such as petroleum, metallurgy, and electric power;

[0003] In ultra-low temperature pipeline systems, sealing is very important for gate valves. Take the ultra-low temperature gate valve for LNG ships as an example. The temperature can reach -100°C. In ultra-low temperature use environments, metal seals are used between the valve plate and the sealing surface 20 of the gate valve. As shown in the figure, when the gate valve is in a closed state, the middle cavity 11 in the valve body 10 will contain low-temperature medium. The low-temperature medium is easily gasified due to the influence of the ambient temperature, which increases the pressure in the middle cavity 11. That is, on the one hand, the pressure cannot be released in time, and on the other hand, due to the influence of high pressure, the sealing component between the valve stem 30 and the valve cover is easy to fail, which leads to poor sealing.

[0004] For example, the Chinese invention patent with publication number: CN112283376A: A self-pressure-relieving bidirectional sealing gate valve with ultra-low temperature middle cavity 11, the disclosed technical solution: the bottom of the valve disc is higher than the bottom of the middle cavity 11, a pressure relief device is arranged on the lower part of the valve disc, and the pressure relief device is a bidirectional pressure relief device; the pressure relief device is designed on the middle cavity 11, and the pressure relief hole is used to relieve pressure by the pressure relief device, and at the same time, the function of bidirectional sealing is realized;

[0005] After the medium is trapped in the middle cavity 11, the pressure relief method of the above technical solution is to appropriately discharge the liquid at the lower end of the middle cavity 11 through the pressure relief device, but the gas in the upper end of the middle cavity 11 is still in a certain high-pressure state. When the valve stem 30 moves relative to the cover plate, the sealing component is still under great pressure, which makes the sealing performance worse, especially in an ultra-low temperature environment, the sealing component will shrink and affect the overall sealing effect. Summary of the invention

[0006] The object of the present invention is to provide an ultra-low temperature gate valve, which can not only relieve the pressure of the low-temperature medium in the gate valve to avoid the reduction of sealing due to excessive pressure in the middle cavity, but also adjust the contact force between the sealing component and the valve stem and the first cover plate according to the pressure in the middle cavity to improve the sealing effect.

[0007] To achieve the above purpose, the present invention provides an ultra-low temperature gate valve, comprising:

[0008] The valve body, the first cover plate, and the valve stem are provided with a channel for the medium to flow through in the valve body. The first cover plate is sealed and installed on the upper end of the valve body to form a middle cavity with the inside of the valve body. The upper part of the valve stem passes through the valve body, and the first cover plate is located on the outside and is driven to move up and down so that the lower part of the valve stem can open and close the channel.

[0009] Wherein, a closed cavity is provided in the first cover plate, and the cavity is connected to the middle cavity through the third through hole;

[0010] Also includes:

[0011] A sealing component installed between the first cover plate and the valve stem;

[0012] Pressure relief components, including:

[0013] A pressing block is located in the cavity and opens and closes the third through hole;

[0014] A first capsule connected to the cavity and capable of expanding to act on the sealing component;

[0015] Among them, the pressure block initially closes the third through hole. When the pressure in the middle cavity reaches a certain level, the pressure block opens the third through hole. At this time, the first sac expands and acts on the sealing component, so that the sealing component is squeezed between the valve stem and the first cover plate.

[0016] In some examples of the present invention, the pressure relief component further includes:

[0017] The elastic member is located in the cavity, and two ends of the elastic member are in contact with the inner wall of the cavity and the pressing block respectively;

[0018] The lower end of the pressing block is a hemispherical or stepped columnar structure, and under the downward elastic force of the elastic member, the lower end of the pressing block closes the third through hole.

[0019] In some examples of the present invention, the first cover plate is provided with radially arranged first through holes;

[0020] The first through hole is in communication with the cavity, and a pressure relief valve in a closed state is connected to the outer end thereof;

[0021] When the pressure in the cavity reaches a certain level, the pressure relief valve is in the open state.

[0022] In some examples of the present invention, the sealing component includes a support body of an annular structure and an elastic lip for sealing;

[0023] The middle part of the lip is provided with a cavity, and the first sac is located in the cavity. When the first sac expands, the first sac drives the inner and outer sides of the lip to act on the first cover plate and the valve stem respectively.

[0024] In some examples of the present invention, the lip portion includes an inner lip and an outer lip;

[0025] The inner lip is located on the inner side of the support body and contacts the valve stem, and the outer lip is located on the outer side of the support body and contacts the first cover plate;

[0026] An open cavity is formed between the inner lip and the outer lip, and the first capsule is located in the open cavity.

[0027] In some examples of the present invention, the lip portion further includes a side lip located on the inner lip and the outer lip and close to the open cavity;

[0028] A pair of side lips limits the first capsule in the open cavity.

[0029] In some examples of the present invention, a second cover plate is connected to the upper end of the first cover plate;

[0030] A packing component is provided between the second cover plate and the valve stem; the packing component is configured to absorb moisture on the valve stem.

[0031] In some examples of the present invention, the packing component includes:

[0032] The support net is an elastic ring structure;

[0033] Moisture-proof packing, which is filled inside the support mesh and contacts the valve stem.

[0034] In some examples of the present invention, the filler component further comprises:

[0035] A second capsule is connected to the cavity, the second capsule is ring-shaped, and can expand and act on the outer peripheral side of the support net;

[0036] The valve stem is provided with a blind hole in the axial direction and a pair of through holes in the radial direction;

[0037] A pair of through holes are respectively connected to the upper part and the lower part of the blind hole;

[0038] When the lower portion of the valve stem closes the channel, a pair of through holes are communicated with the first sac body and the second sac body respectively.

[0039] The present invention also aims to provide a method for using an ultra-low temperature gate valve, by opening and closing the third through hole through a pressure block. On the one hand, the pressure in the middle cavity can be properly relieved to avoid excessive pressure in the middle cavity causing a decrease in the sealing performance of the sealing component. On the other hand, the pressure in the cavity increases, and the expansion of the first bladder can increase the contact force between the sealing component and the valve stem, and the first cover plate, thereby improving the sealing effect; and the expansion change of the first bladder can be adjusted according to the pressure in the middle cavity, which is more applicable.

[0040] A method for using an ultra-low temperature gate valve, specifically comprising the following steps:

[0041] S1, initially, under the action of the elastic member, the pressing block closes the third through hole, the first capsule is in a contracted state, and the sealing component at the first cover plate seals the valve stem normally;

[0042] The valve stem is moved up and down, and the lower end of the valve stem opens and closes the channel in the valve body;

[0043] S2, when the valve stem moves downward to close the channel, the middle cavity in the valve body will trap the low-temperature medium, which will be gasified by the ambient temperature and increase the pressure in the middle cavity;

[0044] When the pressure in the middle cavity is greater than the pressure in the cavity and can overcome the pressure of the elastic member under the action of the pressure difference, the pressing block opens the third through hole, and the pressure in the middle cavity can be properly relieved;

[0045] At this time, the pressure in the cavity increases, and the first bladder gradually expands from contraction and can act on the sealing component, so that the sealing component increases the contact force with the valve stem and the first cover plate, thereby enhancing the sealing effect of the sealing component;

[0046] S3, when the pressure in the cavity reaches a certain level, or the first bladder is close to the expansion limit, the pressure relief valve is opened to release the pressure again and reduce part of the pressure in the cavity;

[0047] After the pressure in the middle cavity is appropriately released, or the pressure relief valve releases the pressure, the pressing block closes the third through hole again under the elastic force of the elastic member;

[0048] S4, when the valve stem moves upward to open the channel, the middle cavity in the valve body will not trap the low-temperature medium, and the pressure in the middle cavity will decrease; the first bladder can maintain a certain expansion to keep the sealing component sealed, or the pressure relief valve is actively opened to return the pressure in the cavity to the initial state.

[0049] Compared with the prior art, the present ultra-low temperature gate valve has the third through hole closed by the pressure block at the beginning. When the pressure in the middle cavity reaches a certain level, the pressure block opens the third through hole, so that the first sac expands and acts on the sealing component. Therefore, on the one hand, the pressure in the middle cavity can be properly relieved to avoid the sealing performance of the sealing component being reduced due to excessive pressure in the middle cavity. On the other hand, as the pressure in the cavity increases, the expansion of the first sac can increase the contact force between the sealing component and the valve stem and the first cover plate, thereby improving the sealing effect. Moreover, the expansion change of the first sac can be adjusted according to the pressure in the middle cavity, so the applicability is stronger.

[0050] Since the first through hole is connected to the cavity and the outer end is connected to the pressure relief valve, when the pressure in the cavity reaches a certain level, the pressure relief valve opens. On the one hand, the pressure in the middle cavity can be buffered and relieved through the cavity first, and then relieved through the pressure relief valve. The stepped pressure relief method can avoid the impact caused by excessive pressure relief in the middle cavity. On the other hand, the pressure relief valve can ensure the expansion effect of the first sac, and avoid the first sac from being damaged due to excessive expansion due to excessive pressure, thus playing a protective role.

[0051] Since the lip in the sealing component includes an inner lip, an outer lip, and a side lip close to the open cavity, on the one hand, the inner lip and the outer lip form a cavity in which the first bladder can be placed, and the side lip can wrap the open cavity to a certain extent, so that when the first bladder is expanded, the peripheral side can contact the lip with a large area, so that the lip can be deformed evenly, and this deformation can better increase the sealing contact between the side lip and the first cover plate and the valve stem;

[0052] Due to the provision of the packing component, the second cover plate can not only further seal the cavity at the first cover plate, but also extend the valve stem seal, and absorb and dry the moisture on the valve stem through the packing component, thereby avoiding the problem of obstruction of the valve stem opening and closing due to condensation of moisture in the outside air on the valve stem; in addition, the second bladder is connected to the cavity, and can expand and act on the supporting net, thereby squeezing the moisture-proof packing through the supporting net, thereby enhancing the moisture-proof packing's effect of removing moisture from the valve stem. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is the overall front view of the present invention;

[0054] Figure 2 yes Figure 1 A partial enlarged view of position A in the middle;

[0055] Figure 3 is a front view of the first capsule in the present invention located inside the sealing component;

[0056] Figure 4 is a schematic diagram of a first cover plate in the present invention from a first viewing angle;

[0057] Figure 5 is a schematic diagram of a second viewing angle of the second cover plate in the present invention;

[0058] Figure 6 yes Figure 1 A partial enlarged view of position B in the middle;

[0059] Figure 7 It is a top view of the packing component in the present invention.

[0060] In the figure: 10, valve body, 11, middle cavity;

[0061] 20. Sealing surface;

[0062] 30, valve stem, 31, blind hole, 32, through hole;

[0063] 40. first cover plate, 41. cavity, 42. first through hole, 43. pressing block, 44. elastic member, 45. pressure relief valve, 46. sealing cover, 47. second through hole, 48. third through hole;

[0064] 50. Second cover plate;

[0065] 60. Sealing component, 61. Inner lip, 62. Outer lip, 63. Side lip, 64. Cavity;

[0066] 70. The first capsule;

[0067] 80. Filling component, 81. Moisture-proof filler, 82. Support net, 83. Second capsule. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solution and advantages of the technical solution of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the drawings of specific embodiments of the present invention. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not necessarily indicate a quantity limitation. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0070] As explained, the axis close to the valve stem 30 is taken as a reference, and the area far from the axis of the valve stem 30 is defined as the outside, and the area close to the axis of the valve stem 30 is defined as the inside;

[0071] like Figure 1 , Figure 2 , Figure 4 , Figure 5 As shown, the present invention is an ultra-low temperature gate valve, comprising:

[0072] The valve body 10, the first cover plate 40, and the valve stem 30 are provided in the valve body 10 with a passage for the medium to flow through. The first cover plate 40 is sealed and installed on the upper end of the valve body 10 to form a middle cavity 11 inside the valve body 10. The upper part of the valve stem 30 passes through the valve body 10, and the first cover plate 40 is located outside and is driven to move up and down so that the lower part of the valve stem 30 can open and close the passage.

[0073] The first cover plate 40 is provided with a closed cavity 41, and the cavity 41 is connected to the middle cavity 11 through a third through hole 48;

[0074] The ultra-low temperature gate valve also includes:

[0075] A sealing component 60 is installed between the first cover plate 40 and the valve stem 30;

[0076] Pressure relief components, including:

[0077] The pressing block 43 is located in the cavity 41 and opens and closes the third through hole 48;

[0078] A first capsule 70 connected to the cavity 41 and capable of expanding to act on the sealing member 60;

[0079] The pressing block 43 closes the third through hole 48. When the pressure in the middle cavity 11 reaches a certain level, the pressing block 43 opens the third through hole 48. At this time, the first capsule 70 expands and acts on the sealing component 60, so that the sealing component 60 is squeezed between the valve stem 30 and the first cover plate 40.

[0080] Specifically, the valve body 10, the first cover plate 40, and the valve stem 30 are of existing structures, that is, a channel for the medium to flow through is provided in the valve body 10, and the channel can be arranged horizontally or curvedly; the first cover plate 40 and the valve body 10 are sealed and installed, for example, the first cover plate 40 and the valve body 10 are first positioned by a positioning pin, and then a plurality of sealing rings or sealing gaskets are provided between them to meet the requirements of low temperature and high pressure sealing;

[0081] like Figure 4 , Figure 5 As shown, the first cover plate 40 is provided with a second through hole 47, that is, the upper part of the valve stem 30 passes through the second through hole 47 to be connected with the driving component, and the driving component can be a handle or a motor. The driving component rotates to drive the valve stem 30 to move up and down, so that the lower end of the valve stem 30 can contact the sealing surface 20 at the channel to complete the opening and closing of the channel. It is explained that the lifting and moving of the valve stem 30 belongs to the prior art and will not be further elaborated here;

[0082] A sealing component 60 and a liquid blocking component are provided between the first cover plate 40 and the valve stem 30; the liquid blocking component is located below the sealing component 60 and is used to block and isolate the liquid on the valve stem 30; the sealing component 60 is a general term for sealing, which can be a sealing ring of a special structure, which can ensure the sealing performance of the upper part of the valve stem 30;

[0083] The pressure block 43 in the pressure relief component can open and close the third through hole 48; the first capsule 70 can expand and contract and contact with the sealing component 60;

[0084] When the ultra-low temperature gate valve is initially used, the pressing block 43 closes the third through hole 48, and the first capsule 70 is in a contracted state; the sealing component 60 normally seals the valve stem 30;

[0085] When the valve stem 30 moves upward and is located at the upper part, the passage in the valve body 10 is in a connected state, and the medium passes normally. Figure 1 As shown, the medium moves from left to right; when the valve stem 30 moves downward and is located at the bottom, the lower part of the valve stem 30 contacts the sealing surface 20 at the channel, so that the channel is in a closed state;

[0086] When the channel is in a closed state, the middle cavity 11 in the valve body 10 will retain part of the low-temperature medium. Affected by the ambient temperature, after a period of time, the low-temperature medium is prone to gasification, which increases the pressure in the middle cavity 11. When the pressure in the middle cavity 11 reaches a certain level, the pressure block 43 is in an open state. For example, the pressure in the middle cavity 11 is 1.1-1.5 times the pressure in the cavity 41.

[0087] When the third through hole 48 is opened, on the one hand, the pressure in the middle cavity 11 can be properly relieved to avoid excessive pressure in the middle cavity 11 causing the sealing performance of the sealing component 60 to decrease. On the other hand, the pressure in the cavity 41 increases. Since the first sac 70 is connected to the cavity 41, the first sac 70 gradually expands from a contracted state and can act on the sealing component 60, so that the sealing component 60 is squeezed between the valve stem 30 and the first cover plate 40, that is, under the action of the first sac 70, the contact force between the inner side of the sealing component 60 and the valve stem 30 is increased, and the contact force between the outer side of the sealing component 60 and the first cover plate 40 is increased, so as to achieve an efficient sealing effect; in addition, the expansion change of the first sac 70 can be adjusted according to the pressure in the middle cavity 11, that is, the greater the pressure in the middle cavity 11, the more the first sac 70 expands, so that the contact between the sealing component 60 and the first cover plate 40 and the valve stem 30 is closer, and the applicability is stronger, so as to avoid the sealing effect being affected by the shrinkage of the sealing component 60 in an ultra-low temperature environment.

[0088] In some examples of the present invention, Figure 2 As shown, the pressure relief component also includes:

[0089] The elastic member 44 is located in the cavity 41, and two ends of the elastic member 44 are in contact with the inner wall of the cavity 41 and the pressing block 43 respectively;

[0090] The lower end of the pressing block 43 is a hemispherical or stepped columnar structure. Under the downward elastic force of the elastic member 44, the lower end of the pressing block 43 closes the third through hole 48.

[0091] Specifically, a slot hole may be provided on the first cover plate 40 , and the slot hole is sealed by a cover 46 to form a cavity 41 of the first cover plate 40 ;

[0092] The elastic member 44 may be a cylindrical spring, which is compressed and located in the cavity 41. At this time, the spring is in contact with the pressing block 43 and the cover 46 respectively.

[0093] When the lower end of the pressing block 43 is a hemispherical structure, under the action of the spring, the hemispherical shape can block the upper end of the third through hole 48 to put it in a closed state. When the lower end of the spring is a columnar structure, under the action of the spring, the columnar shape can be inserted into the third through hole 48 to put it in a closed state.

[0094] It is explained that when this ultra-low temperature gate valve is initially used, a suitable elastic member 44 is selected so that the pressure in the middle cavity 11 can be greater than the pressure in the cavity 41 and reaches a certain level. Under the action of the pressure difference, the pressure block 43 squeezes the elastic member 44 in an open state. After the pressure in the middle cavity 11 drops to a certain level, that is, after the pressure is released, under the action of the elastic force of the elastic member 44, the pressure block 43 closes the third through hole 48 again.

[0095] In some examples of the present invention, Figure 2 As shown, the first cover plate 40 is provided with radially arranged first through holes 42;

[0096] The first through hole 42 is in communication with the cavity 41, and a pressure relief valve 45 in a closed state is connected to the outer end thereof; when the pressure in the cavity 41 reaches a certain level, the pressure relief valve 45 is controlled to be in an open state;

[0097] Specifically, the radially arranged first through holes 42 can facilitate the communication between the first capsule 70 and the cavity 41, and the connection between the pressure relief valve 45 and the cavity 41;

[0098] When the valve stem 30 closes the passage and the low-temperature medium in the middle cavity 11 is gasified so that the pressure in the middle cavity 11 increases, the pressure in the middle cavity 11 reaches a certain level and can overcome the pressure of the elastic member 44 under the action of the pressure difference, and the pressing block 43 is in an open state. For example, the pressure in the middle cavity 11 is P1a, the pressure in the cavity 41 is P2a, and P1a>P2a, and the pressure difference △P=P1a-P2a can overcome the pressure of the elastic member 44, the pressing block 43 is opened, at this time, the pressure in the cavity 41 increases from P2a to P2b, and the pressure in the middle cavity 11 decreases from P1a to P1b, the first capsule 70 expands to pressurize the sealing component 60, and enhances the sealing performance of the sealing component 60; when the pressure difference △P=P1b-P2b cannot overcome the pressure of the elastic member 44, the pressing block 43 closes the third through hole 48;

[0099] When the low-temperature medium in the middle cavity 11 continues to gasify, the pressure in the middle cavity 11 increases from P1b to P1z. It is explained that P1z can be a multiple of P1. Similarly, under the pressure difference overcoming the action of the elastic member 44, the pressure in the cavity 41 increases from P2b to P2z. At this time, the first sac 70 expands to the maximum limit, and the pressure relief valve 45 is in an open state, so that the pressure P2z in the cavity 41 will not continue to increase; the first sac 70 can still pressurize the sealing component 60 to enhance the sealing performance of the sealing component 60, that is, the pressure relief valve 45 can ensure that the cavity 41 and the middle cavity 11 are in a balanced pressure state, and the first sac 70 will not expand due to the pressure change in the middle cavity 11;

[0100] In addition, when the valve stem 30 moves upward to open the channel, the middle cavity 11 in the valve body 10 will not retain the low-temperature medium, and the pressure in the middle cavity 11 decreases; the first capsule 70 can maintain a certain expansion to keep the sealing component 60 sealed, or the pressure relief valve 45 is actively opened, so that the pressure in the cavity 41 returns to the initial state. The active opening or closing of the pressure relief valve 45 can be actively controlled by the lifting and lowering movement of the valve stem 30 and the pressure in the cavity 41, that is, the opening and closing threshold of the pressure relief valve 45 can be manually adjusted or automatically controlled;

[0101] On the one hand, this example can first buffer the pressure of the middle cavity 11 through the cavity 41, and then release the pressure through the pressure relief valve 45. The stepped pressure relief method can avoid the impact caused by the excessive pressure relief of the middle cavity 11. On the other hand, the pressure relief valve 45 can ensure the expansion effect of the first sac 70, and avoid the first sac 70 from being damaged due to excessive expansion due to excessive pressure, thereby playing a protective role.

[0102] In some examples of the present invention, Figure 3 As shown, the sealing component 60 includes a supporting body of an annular structure and an elastic lip for sealing;

[0103] The middle part of the lip has a cavity 64, and the first capsule 70 is located in the cavity 64. When the first capsule 70 expands, the first capsule 70 drives the inner and outer sides of the lip to act on the first cover plate 40 and the valve stem 30 respectively.

[0104] In some examples of the present invention, the lip portion includes an inner lip 61 and an outer lip 62;

[0105] The inner lip 61 is located on the inner side of the support body and contacts the valve stem 30 , and the outer lip 62 is located on the outer side of the support body and contacts the first cover plate 40 ;

[0106] An open cavity 64 is formed between the inner lip 61 and the outer lip 62, and the first capsule 70 is located in the open cavity 64;

[0107] Furthermore, the lip portion further includes a side lip 63 located on the inner lip 61 and the outer lip 62 and close to the opening cavity 64;

[0108] A pair of side lips 63 limits the first capsule 70 in the opening cavity 64;

[0109] Specifically, the support body facilitates the installation and fixation of the sealing component 60;

[0110] In terms of a single cross-section, the outer lip 62 and the inner lip 61 form an approximately "Y"-shaped structure, and a cavity 64 for placing the first capsule 70 is formed therebetween. Preferably, the outer side of the outer lip 62 and the inner side of the inner lip 61 are both arc-shaped structures, which can ensure that there is a certain amount of extrusion between the outer lip 62 and the first cover plate 40, and between the inner lip 61 and the second cover plate 50. At this time, an open, approximately circular cavity 64 is formed between the outer lip 62 and the inner lip 61.

[0111] The side lip 63 is located on the outside of the inner lip 61 and on the inside of the outer lip 62, that is, the side lip 63 can wrap the open cavity 64 to a certain extent, so that when the first bladder 70 is expanded, the peripheral side can contact the lip over a large area, so that the lip can deform evenly, and this deformation can increase the sealing contact between the side lip 63 and the first cover plate 40 and the valve stem 30.

[0112] In some examples of the present invention, Figure 1 , Figure 6 , Figure 7 As shown, the upper end of the first cover plate 40 is connected to the second cover plate 50;

[0113] A packing member 80 is provided between the second cover plate 50 and the valve stem 30;

[0114] The packing member 80 is configured to absorb moisture on the valve stem 30;

[0115] Specifically, when the ultra-low temperature gate valve is opened and closed for the low temperature medium, the valve stem 30 moves up and down, and the temperature of the position of the valve stem 30 near the middle cavity 11 of the valve body 10 is relatively low. There is a situation where the temperature of the valve stem 30 is lower than the ambient temperature. At this time, due to the temperature difference, part of the water vapor between the upper part of the valve stem 30 and the second cover plate 50 condenses into ice, so that the valve stem 30 is blocked from moving up and down, affecting the normal use of the gate valve;

[0116] The second cover plate 50 is sealingly connected to the upper end of the first cover plate 40. At this time, the valve stem 30 passes through the second cover plate 50. The second cover plate 50 can not only further seal the cavity 41 at the first cover plate 40, but also extend the seal of the valve stem 30, and absorb and dry the moisture on the valve stem 30 through the packing component 80, so as to avoid the problem of the valve stem 30 being blocked from opening and closing due to condensation of moisture in the outside air on the valve stem 30.

[0117] In some examples of the present invention, Figure 7 As shown, the filler component 80 includes:

[0118] The support net 82 is an elastic annular structure;

[0119] A moisture-proof filler 81 is filled inside the support net 82 and contacts the valve stem 30;

[0120] In some examples of the present invention, the filler component 80 further includes:

[0121] A second capsule 83 connected to the cavity 41, the second capsule 83 is ring-shaped and can expand to act on the outer peripheral side of the support net 82;

[0122] The valve stem 30 is provided with a blind hole 31 in the axial direction and a pair of through holes 32 in the radial direction;

[0123] A pair of through holes 32 are respectively connected to the upper and lower parts of the blind hole 31;

[0124] When the lower portion of the valve stem 30 closes the passage, the pair of through holes 32 are connected to the first capsule 70 and the second capsule 83 respectively;

[0125] Specifically, the second capsule 83 is similar to the first capsule 70 and can expand and act on the support net 82, and squeeze the moisture-proof filler 81 through the support net 82 to enhance the moisture-proof filler 81's effect of removing moisture from the valve stem 30, that is, the moisture-proof filler 81 is in the form of small particles, which can increase the contact force between the moisture-proof filler 81 and the valve stem 30;

[0126] The blind hole 31 and the pair of through holes 32 on the valve stem 30 can ensure that the cavity 41 on the first cover plate 40 can be connected to the second capsule 83 located on the second cover plate 50;

[0127] It is explained that only when the lower part of the valve stem 30 is closed to the channel, the second capsule 83 is connected to the cavity 41, that is, when the lower part of the valve stem 30 is closed to the channel, the cavity 41 is connected to the through hole 32 on the lower side, the through hole 32 on the lower side is connected to the through hole 32 on the upper side through the axially arranged blind hole 31, and the through hole 32 on the upper side is connected to the second capsule 83.

[0128] A sealing method for an ultra-low temperature gate valve specifically comprises the following steps:

[0129] S1, initially, under the action of the elastic member 44, the pressing block 43 closes the third through hole 48, and the first capsule 70 is in a contracted state;

[0130] The valve stem 30 is moved up and down, and the lower end of the valve stem 30 opens and closes the channel in the valve body 10, and the sealing component 60 at the first cover plate 40 normally seals the valve stem 30;

[0131] S2, when the valve stem 30 moves downward to close the channel, the middle cavity 11 in the valve body 10 will trap the low-temperature medium, and the low-temperature medium will be gasified under the influence of the ambient temperature, so that the pressure in the middle cavity 11 increases;

[0132] When the pressure in the middle cavity 11 is greater than the pressure in the cavity 41 and can overcome the pressure of the elastic member 44 under the action of the pressure difference, the pressing block 43 opens the third through hole 48, and the pressure in the middle cavity 11 can be properly relieved;

[0133] At this time, the pressure in the cavity 41 increases, and the first capsule 70 gradually expands from contraction and can act on the sealing component 60, so that the sealing component 60 increases the contact force with the valve stem 30 and the first cover plate 40, thereby enhancing the sealing effect of the sealing component 60;

[0134] S3, when the pressure in the cavity 41 reaches a certain level, or the first bladder 70 is close to the expansion limit, the pressure relief valve 45 is opened to release the pressure again and reduce part of the pressure in the cavity 41;

[0135] After the pressure in the middle cavity 11 is appropriately released, or the pressure relief valve 45 is released, the pressing block 43 closes the third through hole 48 again under the elastic force of the elastic member 44;

[0136] S4, when the valve stem 30 moves upward to open the channel, the middle cavity 11 in the valve body 10 will not trap the low-temperature medium, and the pressure in the middle cavity 11 decreases; the first bladder 70 can maintain a certain expansion to keep the sealing component 60 sealed, or the pressure relief valve 45 is actively opened, so that the pressure in the cavity 41 returns to the initial state.

[0137] An exemplary implementation of an ultra-low temperature gate valve proposed by the present invention is described in detail above with reference to a preferred embodiment. However, those skilled in the art will appreciate that, without departing from the concept of the present invention, various modifications and variations may be made to the above-mentioned specific embodiments, and various technical features and structures proposed by the present invention may be combined in various ways without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. A cryogenic gate valve, comprising: A valve body (10), a first cover plate (40), and a valve stem (30); a passage for a medium to flow through is provided in the valve body (10); the first cover plate (40) is sealingly mounted on the upper end of the valve body (10) and forms a middle cavity (11) with the interior of the valve body (10); the upper portion of the valve stem (30) passes through the valve body (10), the first cover plate (40) is located on the outside, and is driven to move up and down so that the lower portion of the valve stem (30) can open and close the passage; It is characterized in that A closed cavity (41) is provided in the first cover plate (40), and the cavity (41) is connected to the middle cavity (11) via a third through hole (48); Also includes: A sealing component (60) is installed between the first cover plate (40) and the valve stem (30); Pressure relief components, including: A pressing block (43) is located in the cavity (41) and opens and closes the third through hole (48); A first sac (70) connected to the cavity (41) and capable of expanding to act on the sealing component (60); Initially, the pressure block (43) closes the third through hole (48). When the pressure in the middle cavity (11) reaches a certain level, the pressure block (43) opens the third through hole (48). At this time, the first sac (70) expands and acts on the sealing component (60), so that the sealing component (60) is squeezed between the valve stem (30) and the first cover plate (40).

2. The ultra-low temperature gate valve according to claim 1, characterized in that: The pressure relief component also includes: An elastic member (44) is located in the cavity (41), and two ends of the elastic member (44) are in contact with the inner wall of the cavity (41) and the pressing block (43) respectively; The lower end of the pressing block (43) is a hemispherical or stepped columnar structure, and under the downward elastic force of the elastic member (44), the lower end of the pressing block (43) closes the third through hole (48).

3. The ultra-low temperature gate valve according to claim 2, characterized in that: The first cover plate (40) is provided with radially arranged first through holes (42); The first through hole (42) is in communication with the cavity (41), and a pressure relief valve (45) in a closed state is connected to the outer end thereof; When the pressure in the cavity (41) reaches a certain level, the pressure relief valve (45) is in an open state.

4. The ultra-low temperature gate valve according to claim 1, characterized in that: The sealing component (60) comprises a supporting body of an annular structure and an elastic lip for sealing; A cavity (64) is provided in the middle of the lip, and a first sac (70) is located in the cavity (64). When the first sac (70) expands, the first sac (70) drives the inner and outer sides of the lip to act on the first cover plate (40) and the valve stem (30) respectively.

5. The ultra-low temperature gate valve according to claim 4, characterized in that: The lip portion includes an inner lip (61) and an outer lip (62); The inner lip (61) is located on the inner side of the support body and contacts the valve stem (30), and the outer lip (62) is located on the outer side of the support body and contacts the first cover plate (40); An open cavity (64) is formed between the inner lip (61) and the outer lip (62), and the first capsule (70) is located in the open cavity (64).

6. The ultra-low temperature gate valve according to claim 5, characterized in that: The lip portion further includes a side lip (63) located on the inner lip (61) and the outer lip (62) and close to the open cavity (64); A pair of side lips (63) limits the position of the first capsule (70) in the open cavity (64).

7. The ultra-low temperature gate valve according to any one of claims 1 to 6, characterized in that: The upper end of the first cover plate (40) is connected to a second cover plate (50); A packing component (80) is provided between the second cover plate (50) and the valve stem (30); the packing component (80) is configured to absorb moisture on the valve stem (30).

8. The ultra-low temperature gate valve according to claim 7, characterized in that: The packing component (80) comprises: The support net (82) is an elastic annular structure; The moisture-proof filler (81) is filled inside the support net (82) and is in contact with the valve stem (30).

9. The ultra-low temperature gate valve according to claim 8, characterized in that: The packing component (80) further comprises: A second capsule (83) is connected to the cavity (41), and the second capsule (83) is ring-shaped and can expand to act on the outer peripheral side of the support net (82); The valve stem (30) is provided with a blind hole (31) in the axial direction and a pair of through holes (32) in the radial direction; A pair of through holes (32) are respectively connected to the upper part and the lower part of the blind hole (31); When the lower portion of the valve stem (30) closes the channel, the pair of through holes (32) are respectively connected to the first sac (70) and the second sac (83).

10. A method for using the ultra-low temperature gate valve according to claim 3, characterized in that: The specific steps include: S1, initially, under the action of the elastic member (44), the pressing block (43) closes the third through hole (48), the first capsule (70) is in a contracted state, and the sealing component (60) at the first cover plate (40) performs a normal sealing process on the valve stem (30); The valve stem (30) is moved up and down, and the lower end of the valve stem (30) opens and closes the passage in the valve body (10); S2, when the valve stem (30) moves downward to close the passage, the middle cavity (11) in the valve body (10) will retain the low-temperature medium, and the low-temperature medium will be vaporized under the influence of the ambient temperature, thereby increasing the pressure in the middle cavity (11); When the pressure in the middle cavity (11) is greater than the pressure in the cavity (41), and can overcome the pressure of the elastic member (44) under the action of the pressure difference, the pressing block (43) opens the third through hole (48), and the pressure in the middle cavity (11) can be appropriately relieved; At this time, the pressure in the cavity (41) increases, and the first bladder (70) gradually expands from contraction and can act on the sealing component (60), so that the contact force between the sealing component (60) and the valve stem (30) and the first cover plate (40) is increased, thereby enhancing the sealing effect of the sealing component (60); S3, when the pressure in the cavity (41) reaches a certain level, or the first bladder (70) approaches the expansion limit, the pressure relief valve (45) is opened to release the pressure again and reduce part of the pressure in the cavity (41); After the pressure in the middle cavity (11) is appropriately released, or the pressure relief valve (45) releases the pressure, the pressing block (43) closes the third through hole (48) again under the elastic force of the elastic member (44); S4, when the valve stem (30) moves upward to open the channel, the middle cavity (11) in the valve body (10) will not retain the low-temperature medium, and the pressure in the middle cavity (11) will decrease; the first bladder (70) can maintain a certain expansion to keep the sealing component (60) sealed, or the pressure relief valve (45) is actively opened, so that the pressure in the cavity (41) returns to the initial state.

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