A seal structure for a leak-proof bypass vent valve

Abstract

The application relates to the technical field of valve sealing, in particular to a sealing structure of a leakage-proof bypass discharge valve, which comprises a sealing seat sleeved on the outer portion of a valve rod, a packing cavity for inserting packing is arranged on the inner side of the top portion of the sealing seat, a packing pad, a lower packing ring, a partition ring, an upper packing ring and a packing pressing sleeve are sequentially arranged in the packing cavity from bottom to top, a plurality of studs are arranged on the top surface of the sealing seat, and a packing pressing plate is movably sleeved on the outer portion of the valve rod; the partition ring is arranged between the upper packing ring and the lower packing ring, when the packing pressing plate is pressed downward, the overall height of the partition ring can be increased, so that the upper packing ring and the lower packing ring are respectively extruded upward and downward, compared with the traditional one-way extrusion mode, the application can transmit bidirectional force through the partition ring, and the packing can be uniformly stressed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valve sealing, in particular to a sealing structure of a leakage-proof bypass discharge valve. BACKGROUND

[0002] In the industrial fields of petroleum, chemical industry, nuclear power and the like, a bypass discharge valve as a key component for fluid control, its sealing directly relates to production safety and process stability. In these fields, the medium is mostly corrosive, toxic or high-temperature and high-pressure, once the valve sealing fails and leakage occurs, not only resource waste will be caused, but also safety accidents or environmental pollution can be caused, therefore, the sealing of the bypass discharge valve has a very high requirement.

[0003] In the prior art, the valve rod sealing structure is usually based on a sealing seat as a basic component, specifically, the sealing seat is sleeved on the outside of the valve rod, and the annular gap formed between the two is filled with packing, and the common packing is mostly flexible sealing material. In order to ensure the sealing effect, the packing is pressed by the cooperation of the packing gland and the packing plate. Among them, the packing sleeve directly contacts the packing, and the packing plate provides driving force through connecting pieces such as bolts to transmit pressure to the packing sleeve, and then compacts the packing, so that the packing deforms to fill the gap, and the sealing between the valve rod and the sealing seat is realized.

[0004] However, the extrusion of the packing sleeve on the packing in the existing structure is a one-way action from top to bottom, which makes the stress of the packing present a obvious uneven state. That is, the packing close to the outer end bears the extrusion force of the sleeve directly, and the stress is larger; and the packing close to the inner end has smaller stress due to the influence of extrusion transmission efficiency. When the extrusion degree of the packing sleeve is insufficient, the inner end packing cannot deform sufficiently, which easily leads to poor sealing; when the extrusion degree is sufficient, the outer end packing will be tightly attached to the valve rod due to excessive extrusion, which generates large resistance to the rotation of the valve rod, and affects the operation flexibility of the valve. Therefore, we propose a sealing structure of a leakage-proof bypass discharge valve to solve the above-mentioned problems. SUMMARY

[0005] The present application relates to the technical field of valve sealing, in particular to a sealing structure of a leakage-proof bypass discharge valve.

[0006] The application is realized by the technical scheme that the sealing structure of the leakage-proof bypass discharge valve comprises a sealing seat sleeved on the outer part of the valve rod, a packing cavity for inserting packing is formed in the inner side of the top of the sealing seat, a ring-shaped packing pad, a lower packing ring, a spacer ring, an upper packing ring and a packing pressing sleeve are sequentially arranged in the packing cavity from bottom to top, a plurality of threaded studs are arranged on the top surface of the sealing seat, a packing pressing plate is movably sleeved on the outer part of the valve rod, a through hole is formed in the packing pressing plate and penetrates the threaded studs, a pressing nut is threadedly connected to the top of the threaded studs to tightly abut the top end of the packing pressing sleeve with the packing pressing sleeve.

[0007] The spacer ring comprises a middle annular body, an upper annular body and a lower annular body, the upper annular body and the lower annular body are respectively arranged on the upper and lower sides of the middle annular body, and the upper annular body and the lower annular body respectively abut the bottom surface of the upper packing ring and the top surface of the lower packing ring.

[0008] A pressing transmission assembly is arranged in the side wall of the sealing seat, the input end of the pressing transmission assembly extends above the sealing seat, when the packing pressing plate pushes the input end of the pressing transmission assembly to move downward, the upper annular body and the lower annular body respectively move towards the side away from the middle annular body.

[0009] Optionally, the number of the lower packing rings is four and the number of the upper packing rings is three.

[0010] Optionally, the lower packing ring and the upper packing ring are made of ceramic fiber material or flexible graphite material.

[0011] Optionally, a plurality of embedded grooves are formed in the inner surface of the middle annular body, a sliding block is symmetrically arranged on the inner surface of each embedded groove, a pushing column is arranged on the opposite surface of each sliding block, and the upper annular body and the lower annular body are respectively connected to the pushing columns.

[0012] Optionally, an inclined strut is hingedly arranged on the sliding block, the free ends of the two inclined struts in the same embedded groove are hingedly connected to a pushing block, and the pushing block and the inner wall of the embedded groove are slidingly connected along the depth direction of the embedded groove.

[0013] Optionally, a first guide groove is formed in the inner surface of the packing cavity and opposite to the embedded groove, a second guide groove corresponding to the first guide groove is formed in the top surface of the sealing seat, the second guide groove is communicated with the first guide groove, and the first guide groove is in a stepped shape with the diameter gradually increasing from inside to outside.

[0014] The pressing transmission assembly comprises an abutting column movably inserted into the first guide groove, and the abutting column and the inner wall of the first guide groove are connected by a return spring; when the return spring is in a natural state, one end of the abutting column extends into the second guide groove and the other end of the abutting column is located in the first guide groove.

[0015] Optionally, the pressing transmission assembly further includes a pressing column that is vertically inserted into the second guide groove. The pressing column and the sealing seat are elastically connected by a spring. One end of the abutment column extending into the second guide groove is provided with an inclined slot. The bottom end of the pressing column abuts against the inclined surface in the inclined slot. When the pressing column moves downward, the abutment column can move toward the side closer to the packing cavity.

[0016] Optionally, a sealing sheet is glued to one end of the first guide groove near the packing cavity, and the sealing sheet is made of an elastic material.

[0017] Optionally, the packing sleeve includes a lower sleeve and an upper sleeve, which are elastically connected vertically.

[0018] Optionally, the lower pressure sleeve is a two-stage stepped shaft with an outer diameter that gradually increases from bottom to top, and the bottom diameter of the lower pressure sleeve is adapted to the inner diameter of the packing cavity. In the sealed state, the lower edge of the top of the lower pressure sleeve abuts against the top surface of the sealing seat.

[0019] Compared with the prior art, the present invention provides a sealing structure for a leak-proof bypass discharge valve, which has the following advantages:

[0020] 1. The present invention provides a spacer ring between the upper packing ring and the lower packing ring. When the packing pressure plate is pressed down, the overall height of the spacer ring can increase, thereby squeezing the upper packing ring and the lower packing ring upward and downward respectively. Compared with the traditional unidirectional squeezing method, the present invention can transmit bidirectional force through the spacer ring, which helps to make the packing uniformly stressed.

[0021] 2. The present invention includes a pressing transmission assembly, which is used to convert the downward pressure of the packing plate into a force that drives the height of the spacer ring to increase. The pressing transmission assembly is located outside the packing cavity. Therefore, the setting of the pressing transmission assembly can not only realize the transmission of force, but also will not cause a decrease in the sealing performance of the valve.

[0022] 3. The packing sleeve in this invention has its own elasticity, and the position of the lower packing sleeve can be fixed after the lower packing sleeve abuts against the top surface of the sealing seat. Therefore, this invention can increase the height of the spacer ring alone without changing the position of the lower packing sleeve, so that the upper packing ring and the lower packing ring are subjected to uniform force. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a cross-sectional view of the sealing seat structure according to Embodiment 1 of the present invention;

[0025] Figure 3 This is a schematic diagram of the spacer ring structure of the present invention;

[0026] Figure 4 Figure is the structure diagram of the filler pressing sleeve of the embodiment one of the present application;

[0027] Figure 5 Figure is the structure diagram of the abutting column of the present application;

[0028] Figure 6 Figure is the structure diagram of the abutting column of the present application; Figure 2 Figure is the corresponding enlarged view of A in the middle;

[0029] Figure 7 Figure is the structure diagram of the sealing seat of the embodiment of the present application;

[0030] Figure 8 Figure is the structure diagram of the filler pressing sleeve of the embodiment two of the present application;

[0031] Figure 9 Figure is the structure diagram of the abutting column of the present application; Figure 7 Figure is the corresponding enlarged view of B in the middle.

[0032] In the figure: 100, valve rod; 200, sealing seat; 201, stud; 202, first guide groove; 203, second guide groove; 300, filler gasket; 400, lower filler ring; 500, spacer ring; 501, middle annular body; 502, upper annular body; 503, lower annular body; 504, embedded groove; 505, sliding block; 506, pushing column; 507, inclined support; 508, pushing block; 600, upper filler ring; 700, filler pressing sleeve; 701, lower pressing sleeve; 702, upper pressing sleeve; 703, guide rod; 800, filler pressing plate; 900, pressing transmission assembly; 901, abutting column; 902, sealing sheet; 903, reset spring; 904, inclined notch; 905, pressing column. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0034] Embodiment one: please refer to Figure 1 - Figure 6The embodiment of the present application provides a sealing structure of a leakage-proof bypass exhaust valve, which comprises a sealing seat 200 sleeved on the outside of a valve rod 100, a packing cavity for inserting packing is formed in the top inner side of the sealing seat 200, the packing cavity is annular, and the packing cavity is sequentially provided with an annular packing pad 300, a lower packing ring 400, a partition ring 500, an upper packing ring 600 and a packing pressing sleeve 700 from bottom to top, and the top surface of the sealing seat 200 is further provided with a plurality of threaded studs 201, the outside of the valve rod 100 movably sleeves a packing pressing plate 800, a through hole is formed in the packing pressing plate 800 and penetrates the packing pressing plate 800, the threaded studs 201 are threadedly connected with pressing nuts at the top, so that the packing pressing plate 800 is tightly abutted with the top end of the packing pressing sleeve 700; therefore, the packing pressing plate 800 can be driven to be pressed down by rotating the pressing nuts, so that the packing ring is tightly pressed to realize the sealing effect.

[0035] It should be noted that the number of the lower packing ring 400 is four, and the number of the upper packing ring 600 is three. The lower packing ring 400 and the upper packing ring 600 are made of ceramic fiber material or flexible graphite material, and the two materials have high-temperature resistance, so that they can be used for a long time in a high-temperature and high-pressure environment. In addition, the bottom end of the packing pressing sleeve 700 extends into the packing cavity, and the top end thereof is located above the sealing seat 200 and abuts against the packing pressing plate 800.

[0036] Further, the partition ring 500 comprises a middle annular body 501, an upper annular body 502 and a lower annular body 503, the upper annular body 502 and the lower annular body 503 are respectively located on the upper and lower sides of the middle annular body 501, and the upper annular body 502 and the lower annular body 503 are respectively abutted against the bottom surface of the upper packing ring 600 and the top surface of the lower packing ring 400; the middle annular body 501, the upper annular body 502 and the lower annular body 503 are made of stainless steel, and have good structural strength and high-temperature resistance and wear resistance.

[0037] In order to realize that the upper annular body 502 and the lower annular body 503 respectively extend upward and downward to tightly press the packing, the embodiment further has the following design:

[0038] A pressing transmission assembly 900 is arranged in the side wall of the sealing seat 200, the input end of the pressing transmission assembly 900 extends to above the sealing seat 200, when the packing pressing plate 800 pushes the input end of the pressing transmission assembly 900 to move downward, the upper annular body 502 and the lower annular body 503 respectively move away from the middle annular body 501. That is, the pressing transmission assembly 900 serves as a power transmission mechanism, which can convert the downward pressure of the packing pressing plate 800 into the acting force of the upper annular body 502 and the lower annular body 503 moving away from each other.

[0039] The outer surface of the middle annular body 501 is inwardly recessed to form a plurality of embedded grooves 504. In this embodiment, the number of the embedded grooves 504 is four. The inner part of each embedded groove 504 is symmetrically provided with a sliding block 505. The back surface of each sliding block 505 is provided with a push column 506. The two push columns 506 are connected to the upper annular body 502 and the lower annular body 503 respectively. Specifically, the top wall and the bottom wall of the middle annular body 501 are provided with shaft holes for the push column 506 to pass through. The push column 506 and the upper annular body 502 / lower annular body 503 can be integrally formed. The end of the push column 506 located in the embedded groove 504 is provided with external threads. The push column 506 penetrates through the corresponding sliding block 505 and is locked and fixed by a nut.

[0040] It is worth mentioning that the inner wall of the embedded groove 504 is also provided with a vertical sliding rail. The sliding block 505 is in sliding cooperation with the sliding rail, so as to improve the stability of the sliding block 505. In addition, the sliding block 505 is hingedly provided with a diagonal brace 507. The free ends of the two diagonal braces 507 located in the same embedded groove 504 are hingedly connected to a push block 508. The push block 508 is in sliding cooperation with the inner wall of the embedded groove 504 along the depth direction of the embedded groove 504. The inner wall of the embedded groove 504 is provided with a sliding groove along the depth direction of the embedded groove 504. The push block 508 is in sliding cooperation with the sliding groove, so as to enhance the stability of the push block 508.

[0041] In addition, the inner surface of the filler cavity and the position opposite to the embedded groove 504 are provided with a first guide groove 202. The top surface of the sealing seat 200 is provided with a second guide groove 203 corresponding to the first guide groove 202. The first guide groove 202 is horizontally distributed, and the second guide groove 203 is vertically distributed. The second guide groove 203 is in communication with the first guide groove 202, and the two form an L-shaped through groove. The first guide groove 202 is in the shape of a stepped diameter gradually increasing from inside to outside. In addition, the compression transmission assembly 900 includes an abutting column 901 movably inserted into the first guide groove 202. The diameter of the abutting column 901 is matched with the inner diameter of the thinnest section of the first guide groove 202. The cross section of the abutting column 901 is in the shape of a rounded rectangle.

[0042] In this embodiment, the end of the first guide groove 202 close to the filler cavity is glued and attached with a sealing sheet 902. The sealing sheet 902 is made of elastic material, such as fluorine rubber, which has a certain ductility and high temperature resistance. The sealing sheet 902 can prevent the medium in the valve body from entering the first guide groove 202, so as to ensure the sealing effect.

[0043] As Figure 6As shown, the abutting column 901 and the inner wall of the first guide groove 202 are connected through the reset spring 903; specifically, the reset spring 903 is sleeved on the outside of the abutting column 901, one end of the reset spring 903 is glued and fixed with the inner wall of the first guide groove 202, and the other end is glued and fixed with the outer end inner edge of the abutting column 901. And the glue used for gluing can adopt high-temperature silicone glue, which can still maintain good fixing effect in high-temperature environment.

[0044] When the reset spring 903 is in a natural state, i.e. not under external force, at this time one end of the abutting column 901 extends into the second guide groove 203, and the other end is located in the first guide groove 202. And the end of the abutting column 901 extending into the second guide groove 203 is provided with a beveled notch 904, which is opposite to the top end of the second guide groove 203.

[0045] In this embodiment, the compression transmission assembly 900 further comprises a pressing column 905 movably inserted into the second guide groove 203 in the vertical direction, and the pressing column 905 and the sealing seat 200 are elastically connected through a spring; both ends of the spring are respectively welded and fixed with the top surface of the sealing seat 200 and the top end lower edge of the pressing column 905. And the bottom end of the pressing column 905 abuts against the inclined surface in the beveled notch 904, and when the pressing column 905 moves downward, the abutting column 901 can move towards the side close to the packing cavity.

[0046] In summary, in the specific assembly process, the packing gasket 300, the lower packing ring 400, the spacer ring 500, the upper packing ring 600 and the packing pressing sleeve 700 are sequentially inserted into the packing cavity. It should be noted that since the lower packing ring 400 / upper packing ring 600 is a circular ring formed by a strip-shaped material, the joints of the adjacent two lower packing rings 400 / upper packing rings 600 need to be distributed staggered. And in this initial state, the top end of the packing pressing sleeve 700 is higher than the top end of the pressing column 905.

[0047] Then the packing pressing plate 800 is sleeved on the outside of the valve stem 100, and the packing pressing plate 800 is driven to move downward by continuously tightening the compression nut; at the beginning, the packing pressing plate 800 pushes the packing pressing sleeve 700 to move downward, and the packing pressing sleeve 700 extrudes the upper packing ring 600, the lower packing ring 400 and the spacer ring 500 downward; subsequently, the packing pressing plate 800 also abuts against the pressing column 905 and pushes the pressing column 905 to move downward, under the action of the pressing column 905, the abutting column 901 extends outward and extrudes the pushing block 508 inward, at the same time, the upper annular body 502 and the lower annular body 503 move towards the upper and lower sides respectively, further extruding the upper packing ring 600 and the lower packing ring 400.

[0048] Since the traditional packing pressing sleeve 700 can only extrude the packing ring from top to bottom, the force on the packing rings is uneven; in the embodiment, the upper packing ring 600 can be extruded from both top and bottom, and the lower packing ring 400 can also be extruded downward, which helps to make the force on the packing rings more uniform, thereby improving the packing sealing effect.

[0049] Embodiment two: please refer to Figure 7 Figure 9 The embodiment also provides a sealing structure of the anti-leakage bypass discharge valve, and the difference between the embodiment and the first embodiment is that the packing pressing sleeve 700 comprises a lower pressing sleeve 701 and an upper pressing sleeve 702, and the lower pressing sleeve 701 and the upper pressing sleeve 702 are elastically connected in the vertical direction. Specifically, the bottom surface of the upper pressing sleeve 702 is provided with a guide rod 703, the top surface of the lower pressing sleeve 701 is provided with a guide hole for inserting the guide rod 703, and the outer portion of the guide rod 703 is further sleeved with a spring, and the two ends of the spring are respectively in abutment with the lower pressing sleeve 701 and the upper pressing sleeve 702.

[0050] Further, the lower pressing sleeve 701 is in a two-segment stepped shaft shape with the outer diameter gradually increasing from bottom to top, and the bottom diameter of the lower pressing sleeve 701 is matched with the inner diameter of the packing cavity, and in the sealing state, the lower edge of the top portion of the lower pressing sleeve 701 is in abutment with the top surface of the sealing seat 200.

[0051] In summary, in the actual assembly process, when the packing gasket 300, the lower packing ring 400, the spacer ring 500, the upper packing ring 600 and the packing pressing sleeve 700 are sequentially inserted into the packing cavity, the lower edge of the top portion of the lower pressing sleeve 701 is not in contact with the sealing seat 200, and the top end of the upper pressing sleeve 702 is also higher than the top end of the pressing column 905; with the continuous downward movement of the packing pressing plate 800, first, the packing pressing plate 800 is in abutment with the upper pressing sleeve 702 and pushes the whole lower pressing sleeve 700 downward, and in this process, the upper packing ring 600, the spacer ring 500 and the lower packing ring 400 also move downward.

[0052] When the lower edge of the top portion of the lower pressing sleeve 701 is in abutment with the top surface of the sealing seat 200, the position of the lower pressing sleeve 701 is fixed and no longer moves, and with the continuous downward movement of the packing pressing plate 800, the packing pressing plate 800 is in abutment with the top end of the pressing column 905 and indirectly pushes the upper annular body 502 and the lower annular body 503 to move away from each other, thereby extruding the upper packing ring 600 and the lower packing ring 400.

[0053] ​The difference between this embodiment and Embodiment 1 is that: firstly, the upper packing ring 600 and the lower packing ring 400 are initially compressed by the packing sleeve 700, and then the upper packing ring 600 and the lower packing ring 400 are squeezed from the middle to both sides respectively. The purpose is to make the compression amplitude of the upper packing ring 600 and the lower packing ring 400 equal, so as to avoid the upper packing ring 600 being squeezed too much or the lower packing ring 400 being squeezed too little.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A sealing structure for a leak-proof bypass discharge valve, comprising a sealing seat fitted onto the outside of the valve stem, characterized in that: The sealing seat has a packing cavity for inserting packing material on its top inner side. The packing cavity contains, from bottom to top, an annular packing pad, a lower packing ring, a spacer ring, an upper packing ring, and a packing sleeve. The top surface of the sealing seat is also provided with several studs. A packing pressure plate is movably fitted on the outside of the valve stem. The packing pressure plate has a through hole for the studs to pass through. The top of the studs is threaded with a clamping nut so that the packing pressure plate and the top of the packing sleeve are tightly abutted together. The spacer ring includes a middle ring, an upper ring, and a lower ring. The upper and lower rings are located on the upper and lower sides of the middle ring, respectively, and the upper and lower rings abut against the bottom surface of the upper packing ring and the top surface of the lower packing ring, respectively. A pressing transmission assembly is provided inside the side wall of the sealing seat. The input end of the pressing transmission assembly extends to the top of the sealing seat. When the packing pressure plate pushes the input end of the pressing transmission assembly downward, the upper annular body and the lower annular body move toward the side away from the middle annular body, respectively. The outer surface of the middle annular body is recessed inward and has several embedded grooves. Slider blocks are symmetrically arranged on the upper and lower sides of the inner surface of the embedded grooves. Pushing posts are provided on the opposite sides of the two sliders. The two pushing posts are respectively connected to the upper annular body and the lower annular body. The slider is hinged with a diagonal brace. The free ends of the two diagonal braces located in the same inner groove are hinged to a push block. The push block and the inner wall of the inner groove slide in a sliding fit along the depth direction of the inner groove. The inner surface of the filling cavity is provided with a first guide groove at the position directly opposite the inner groove. The top surface of the sealing seat is provided with a second guide groove that corresponds to the first guide groove. The second guide groove communicates with the first guide groove. The first guide groove is in the shape of a step with the diameter gradually increasing from the inside to the outside. The pressing transmission assembly includes an abutment post that is movably inserted into the first guide groove. The abutment post and the inner wall of the first guide groove are connected by a return spring. When the return spring is in its natural state, one end of the abutment post extends into the second guide groove, and the other end is located in the first guide groove. The pressing transmission assembly also includes a pressing column that is vertically inserted into the second guide groove. The pressing column and the sealing seat are elastically connected by a spring. One end of the abutment column extending into the second guide groove is provided with an inclined slot. The bottom end of the pressing column abuts against the inclined surface in the inclined slot. When the pressing column moves downward, the abutment column can move toward the side closer to the packing cavity.

2. The sealing structure of the leak-proof bypass discharge valve according to claim 1, characterized in that: The number of lower packing rings is four, and the number of upper packing rings is three.

3. The sealing structure of the leak-proof bypass discharge valve according to claim 1, characterized in that: Both the lower and upper packing rings are made of ceramic fiber or flexible graphite.

4. The sealing structure of the leak-proof bypass discharge valve according to claim 1, characterized in that: A sealing sheet is glued to one end of the first guide groove near the packing cavity, and the sealing sheet is made of elastic material.

5. The sealing structure of the leak-proof bypass discharge valve according to claim 1, characterized in that: The packing sleeve includes a lower sleeve and an upper sleeve, which are elastically connected vertically.

6. The sealing structure of the leak-proof bypass discharge valve according to claim 5, characterized in that: The lower pressure sleeve is a two-stage stepped shaft with an outer diameter that gradually increases from bottom to top, and the bottom diameter of the lower pressure sleeve is adapted to the inner diameter of the packing cavity. In the sealed state, the lower edge of the top of the lower pressure sleeve abuts against the top surface of the sealing seat.

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