Hot isostatic press end cap seal structure and method

Abstract

The end cover sealing structure of hot isostatic press includes cylinder and end cover, the end cover extends into the cylinder, the cylinder is equipped with sealing combination for sealing the end cover, the bottom of the end cover is fixed with cooling cover, the top surface of the cooling cover is equipped with circulating water channel connected with external water source and O-shaped sealing ring sealing matched with the bottom surface of the end cover, the sealing combination includes lower sealing frame assembly coaxially fixed on the outer periphery of the cooling cover and sealing contacted with the inner wall of the cylinder and upper sealing ring assembly located above the lower sealing frame assembly, the upper sealing ring assembly includes inverted U-shaped cross-section without skeleton sealing ring and copper support ring, the inner ring of the inverted U-shaped cross-section without skeleton sealing ring is contacted with the outer wall of the cooling cover and a gap is formed between them, the outer ring is contacted with the inner wall of the cylinder and a gap is also formed between them, the copper support ring is matched with the top surface inclined surface of the inverted U-shaped cross-section without skeleton sealing ring and is respectively attached with the inner wall of the cylinder and the bottom surface of the end cover.The sealing life of the end cover of hot isostatic press is prolonged.The application also provides a sealing method of end cover of hot isostatic press.

Description

Technical Field

[0001] The invention relates to a hot isostatic press end cover sealing structure and method, belonging to the technical field of hot isostatic presses. Background Art

[0002] The hot isostatic pressing machine uses hot isostatic pressing technology to apply isostatic pressure to metal powder in a high-temperature and high-pressure sealed container with high-pressure argon, nitrogen and other inert gases as the medium. The temperature inside the container is generally 1000-2000℃, and the internal pressure can reach thousands of MPa. Under the action of high temperature and high pressure, the material is sintered and densified to form high-density billets or parts. It can replace traditional processes such as forging and casting, and can also serve as a complement to forming processes such as metal injection molding, pressing and sintering. It is an indispensable processing technology for the research and development of new materials. The working cylinder in the hot isostatic press includes a cylinder body and an end cover. The mold containing the workpiece is placed in the cylinder body and sealed with the end cover. The end cover is sealed by a sealing frame and a main seal. The sealing frame is equipped with one or more sealing rings to protect the main seal. The main seal is sealed by a combination of a copper sealing ring and a Y-shaped sealing ring. When the temperature and air pressure of the working cylinder increase, the outer lip and inner lip of the Y-shaped sealing ring will fully open, the outer lip and the inner wall of the working cylinder are fully in close contact, and the inner lip and the outer wall of the end cover are fully in close contact, forming a closed container in the working cylinder. As the pressure in the working cylinder increases, the Y-shaped sealing ring squeezes the copper sealing ring, causing it to deform and form a full mechanical seal with the inner wall of the working cylinder and the outer wall of the end cover, respectively, thereby completing the sealing during the entire extrusion process.

[0003] There are two main problems that need to be solved for the main seal: (1) The problem of the outer edge of the Y-shaped seal ring being squeezed into the gap between the copper seal ring and the inner wall of the working cylinder under high pressure needs to be solved: Since the Y-shaped seal ring is a rubber ring with a relatively soft texture, when the pressure is not high, the outer edge of the Y-shaped seal ring is squeezed into the gap between the copper seal ring and the inner wall of the working cylinder under the pressure of the working fluid. As the pressure in the working cylinder increases, the copper seal ring deforms sufficiently, and the outer edge of the Y-shaped seal ring squeezed into the gap will be cut off; as the number of uses increases, the outer edge of the Y-shaped seal ring is damaged more and more, and eventually the seal fails; (2) Under low pressure, since the copper seal ring provides support for the Y-shaped seal ring, under higher pressure, the diameter of the working cylinder is constantly increasing, and a gap is formed between the copper seal ring and the inner wall of the cylinder, which will cause the copper seal ring to be unable to provide support for the Y-shaped seal ring, and will also cause the seal to fail. Therefore, how to solve the sealing problem of the end cover seal of the ultra-high pressure and high temperature isostatic press is of great significance for the normal use of the equipment. Summary of the Invention

[0004] The hot isostatic press end cover sealing structure provided by the present invention effectively improves the sealing reliability and effectiveness of the frameless sealing ring, extends its service life, ensures effective support for the frameless sealing ring, and compresses the frameless sealing ring, copper support ring and the inner wall of the cylinder body from the inside to the outside in sequence to ensure the sealing effect, reduce the probability of sealing failure, and extend the sealing life of the hot isostatic press end cover.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The end cover sealing structure of the hot isostatic press comprises a cylinder body and an end cover covering the cylinder body, the end cover extends into the cylinder body, and a sealing combination for sealing the end cover is provided in the cylinder body, characterized in that: the bottom of the end cover is fixed with a cooling cover for cooling the end cover and the sealing combination, a circulating water channel connected to an external water source and an O-ring sealingly matched with the bottom surface of the end cover are provided on the top surface of the cooling cover, the sealing combination comprises a lower sealing frame assembly coaxially fixed to the outer periphery of the cooling cover and in sealing contact with the inner wall of the cylinder body, and an upper sealing ring assembly located above the lower sealing frame assembly, the upper sealing ring assembly comprises a frameless sealing ring with an inverted U-shaped cross section and a copper support ring covering the frameless sealing ring, the inner ring of the frameless sealing ring contacts the outer wall of the cooling cover and a gap is formed between the two, the outer ring contacts the inner wall of the cylinder body and a gap is also formed between the two, the copper support ring cooperates with the inclined surface of the top surface of the frameless sealing ring and fits respectively with the inner wall of the cylinder body and the bottom surface of the end cover.

[0007] Preferably, the lower sealing frame assembly includes an annular sealing frame coaxially fixed to the bottom of the cooling cover and a copper sealing ring clamped in the groove of the annular sealing frame. There are multiple copper sealing rings and they are respectively in sealing contact with the inner wall of the cylinder body. The cooling cover is clamped between the end cover and the annular sealing frame. The copper support ring, the cooling cover, the annular sealing frame and the inner wall of the cylinder body are combined to form an annular cavity, and the skeleton-free sealing ring is arranged in the annular cavity.

[0008] Preferably, the skeleton-free sealing ring has an inner lip and an outer lip, an inverted U-shaped cavity is formed between the inner lip and the outer lip, the inner lip is in transition fit contact with the outer wall of the cooling cover, and the outer lip is in interference fit contact with the inner wall of the cylinder body.

[0009] Preferably, the inner lip has an inner ring surface arranged opposite to the outer wall of the cooling cover, and the outer lip has an outer ring surface arranged opposite to the inner wall of the cylinder body, the inner ring surface and the outer ring surface are connected by the upper top surface, the copper support ring is covered on the upper top surface, the angle between the inner ring surface and the upper top surface is a right angle, the top surface of the copper support ring is in contact with the end cover, and the outer wall is in contact with the inner wall of the cylinder body.

[0010] Preferably, the outer ring surface and the upper top surface are transitioned by chamfering to form an inclined upper chamfered surface, and a positioning stop for positioning the copper support ring and having a right-angled cross-section is provided on the bottom of the end cover. The top surface of the copper support ring is fitted with the positioning stop, and the bottom surface is fitted with the upper top surface and the upper chamfered surface, forming an inclined surface fit between the copper support ring and the top surface of the skeleton-free sealing ring.

[0011] Preferably, the inner ring surface is composed of an inner upper ring surface and an inner lower ring surface connected in sequence from top to bottom. The inner upper ring surface is vertically arranged and connected perpendicularly to the upper top surface. An angle of 170 degrees to 180 degrees is formed between the inner upper ring surface and the inner lower ring surface. The inner lower ring surface and the bottom surface of the inner lip are transitioned through an inner chamfered surface. The angle between the inner chamfered surface and the inner lower ring surface is greater than 90 degrees, and the angle between the inner chamfered surface and the bottom surface of the inner lip is also greater than 90 degrees. The angle edge of the inner lower ring surface and the inner chamfered surface is in transition-fit contact with the outer wall of the cooling cover, and the inner ring surface is gap-fitted with the outer wall of the cooling cover.

[0012] Preferably, the outer ring surface is composed of an outer upper ring surface and an outer lower ring surface connected in sequence from top to bottom, the outer upper ring surface is connected to the upper chamfered surface, the outer lower ring surface and the bottom surface of the outer lip are transitioned through the outer chamfered surface, the angle between the outer chamfered surface and the outer lower ring surface is greater than 90 degrees, and the angle between the outer chamfered surface and the bottom surface of the outer lip is also greater than 90 degrees, the angle edge between the outer lower ring surface and the outer chamfered surface is interference fit with the inner wall of the cylinder body, and the outer ring surface is clearance fit with the inner wall of the cylinder body.

[0013] Preferably, the position of the angle edge between the inner chamfered surface and the bottom surface of the inner lip is higher than the position of the angle edge between the outer chamfered surface and the bottom surface of the outer lip, the inverted U-shaped cavity is in a downward flaring shape, and the flaring angle is 18 degrees to 25 degrees, the inner lower section annular surface and the outer lower section annular surface are not parallel, and a downward flaring angle of 8 degrees to 13 degrees is formed between the two.

[0014] A hot isostatic press end cover sealing method adopts the hot isostatic press end cover sealing structure described above for sealing, and is characterized in that: according to the sealing requirements of the end cover in the hot isostatic press, the sealing performance of the lower sealing frame assembly and the sealing performance of the upper sealing ring assembly are designed, and the lower sealing frame assembly and the upper sealing ring assembly form a two-layer sealing structure from bottom to top to seal the end cover; according to the sealing performance of the lower sealing frame assembly and the upper sealing ring assembly, the structure of the circulating water channel in the cooling cover and the flow rate and flow velocity of the cooling water in the circulating water channel are designed, so that the operating temperatures of the lower sealing frame assembly and the upper sealing ring assembly are respectively lower than their respective temperature resistance upper limits.

[0015] Preferably, designing the sealing performance of the upper sealing ring assembly refers to: determining the material and hardness of the skeletonless sealing ring, designing the contact area between the skeletonless sealing ring and the copper support ring and the structure of the skeletonless sealing ring, so that the skeletonless sealing ring pushes the copper support ring to deform synchronously radially during the compression deformation process to completely fill the radial gap between the cooling cover and the inner wall of the cylinder body. The skeletonless sealing ring generates pressure on the inner wall of the cylinder body and the end cover respectively through the copper support ring to achieve high-pressure static sealing.

[0016] The beneficial effects of the invention are:

[0017] In the hot isostatic press end cover sealing structure of the present invention, the circulating water channel on the cooling cover is connected to the external water source, which can form continuous cooling for the end cover and the sealing combination, reduce the working temperature of the end cover and the sealing combination under hot isostatic pressing, and reduce the influence of high temperature on the sealing combination. The lower sealing frame assembly provides the first layer of sealing for the end cover and forms protection for the upper sealing ring assembly. The upper sealing ring assembly provides the second layer of sealing for the end cover. The boneless sealing ring in the upper sealing ring assembly is in an inverted U shape, and a preliminary sealing is formed by the contact between the boneless sealing ring and the outer wall of the cooling cover and the inner wall of the cylinder. The sealing is achieved by increasing the deformation flow space of the skeleton-less sealing ring when under pressure through the gaps formed between the skeleton-less sealing ring and the outer wall of the cooling cover and the inner wall of the cylinder body, and the skeleton-less sealing ring will not form excessive force deformation when installed in place, the initial deformation is small, and the gap is gradually filled during the deformation process to form the skeleton-less sealing ring with multiple changes in stiffness, thereby reducing the flow deformation rate of the skeleton-less sealing ring and effectively reducing the probability of the skeleton-less sealing ring being squeezed into the space between the copper support ring and the inner wall of the cylinder body due to deformation. The circulating water channel in the cooling cover cools the skeleton-less sealing ring, increases the flow deformation space of the skeleton-less sealing ring, and changes the stiffness of the skeleton-less sealing ring multiple times during the deformation process. The combination of these three effects effectively improves the sealing reliability and effectiveness of the skeleton-less sealing ring and extends its service life. The copper support ring cooperates with the inclined surface of the top surface of the skeleton-less sealing ring to prevent the skeleton-less sealing ring from squeezing into the space between the copper support ring and the inner wall of the cylinder body, and also increases the contact area between the copper support ring and the skeleton-less sealing ring, thereby improving the support capacity of the copper support ring to the skeleton-less sealing ring, increasing the initial stiffness and pressure bearing capacity of the skeleton-less sealing ring, and reducing the skeleton-less sealing ring. The pressure-bearing deformation reduces the probability of permanent damage to the skeleton-free sealing ring under high pressure, and the pressure on the skeleton-free sealing ring is transmitted radially to the inner wall of the cylinder through the cooperation of the copper support ring and the inclined surface of the top surface of the skeleton-free sealing ring, and is transmitted vertically to the end cover, pushing the copper support ring to deform radially and keep in contact with the inner wall of the cylinder, ensuring effective support for the skeleton-free sealing ring. The skeleton-free sealing ring, copper support ring and the inner wall of the cylinder are pressed tightly from the inside to the outside, ensuring the sealing effect, reducing the probability of sealing failure, and extending the sealing life of the end cover of the hot isostatic press. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1Schematic diagram of the sealing structure of the end cover of the hot isostatic press in a specific embodiment.

[0019] Figure 2 for Figure 1 A partial enlarged schematic diagram.

[0020] Figure 3 Schematic diagram of the annular cavity formed by the copper support ring, cooling cover, annular sealing frame and cylinder inner wall.

[0021] Figure 4 Schematic diagram of a skeleton-free sealing ring.

[0022] Figure 5 Another schematic diagram of a frameless sealing ring.

[0023] Figure 6 This is a schematic diagram of the skeleton-less sealing ring being compressed and deformed to completely fill the radial gap between the cooling cover and the inner wall of the cylinder body. DETAILED DESCRIPTION

[0024] The following combination Figures 1 to 6 The embodiments of the present invention are described in detail.

[0025] The end cover sealing structure of the hot isostatic press comprises a cylinder body 1 and an end cover 2 covering the cylinder body 1. The end cover 2 extends into the cylinder body. A sealing assembly is provided in the cylinder body 1 to seal the end cover 2. The feature is that a cooling cover 3 for cooling the end cover 2 and the sealing assembly is fixed to the bottom of the end cover 2. A circulating water channel 31 connected to an external water source and an O-ring 32 sealingly matched with the bottom surface of the end cover are provided on the top surface of the cooling cover 3. The sealing assembly comprises a sealing ring 3 coaxially fixed to the outer periphery of the cooling cover 3 and in sealing contact with the inner wall of the cylinder body. The lower sealing frame assembly 4 and the upper sealing ring assembly 5 located above the lower sealing frame assembly 4, the upper sealing ring assembly 5 includes a frameless sealing ring 6 with an inverted U-shaped cross section and a copper support ring 7 covering the frameless sealing ring 6, the inner ring of the frameless sealing ring 6 contacts the outer wall of the cooling cover 3 and a gap is formed therebetween, the outer ring contacts the inner wall of the cylinder body 1 and a gap is also formed therebetween, the copper support ring 7 cooperates with the top inclined surface of the frameless sealing ring 6 and fits respectively with the inner wall of the cylinder body 1 and the bottom surface of the end cover 2.

[0026] In the above-mentioned hot isostatic press end cover sealing structure, the circulating water channel 31 on the cooling cover 3 is connected to the external water source, which can continuously cool the end cover 2 and the sealing combination. The O-ring 32 seals the cooling cover 3 and the end cover 2 to prevent the cooling water from leaking from the cooling cover 2 and the end cover 3 to the cylinder body 1. The circulating cooling water reduces the working temperature of the end cover 2 and the sealing combination under hot isostatic pressing to reduce the impact of high temperature on the sealing combination. The lower sealing frame assembly 4 provides the first layer of sealing for the end cover 2 and forms protection for the upper sealing ring assembly 5. The upper sealing ring assembly 5 provides the second layer of sealing for the end cover 2. The upper sealing ring assembly 5 has no The skeleton sealing ring 6 is in an inverted U shape, and a preliminary seal is formed by the contact between the skeleton sealing ring 6 and the outer wall of the cooling cover 3 and the inner wall of the cylinder body 1. The gaps formed between the skeleton sealing ring 6 and the outer wall of the cooling cover 3 and the inner wall of the cylinder body 1 respectively increase the deformation flow space of the skeleton sealing ring 6 when under pressure, and the skeleton sealing ring 6 will not form excessive force deformation when installed in place. The initial deformation is small, and the gap is gradually filled during the deformation process to form the skeleton sealing ring with multiple changes in stiffness, thereby reducing the flow deformation rate of the skeleton sealing ring 6 and effectively reducing the probability of the skeleton sealing ring being squeezed into the space between the copper support ring 7 and the inner wall of the cylinder body 1 due to deformation. The cooling of the skeleton-free sealing ring 6 by the circulating water channel in 3, the increase of the flow deformation space of the skeleton-free sealing ring 6, and the multiple changes in stiffness during the deformation process of the skeleton-free sealing ring 6, the combination of these three effects effectively improves the sealing reliability and effectiveness of the skeleton-free sealing ring and prolongs its service life. The cooperation between the copper support ring 7 and the top inclined surface of the skeleton-free sealing ring 6 prevents the skeleton-free sealing ring 6 from squeezing into the space between the copper support ring 7 and the inner wall of the cylinder body 1, and also increases the contact area between the copper support ring 7 and the skeleton-free sealing ring 6, thereby improving the supporting capacity of the copper support ring 7 to the skeleton-free sealing ring 6 and increasing the initial stiffness and pressure bearing capacity of the skeleton-free sealing ring 6. The ability to reduce the pressure deformation of the skeleton-less sealing ring 6, and the probability of permanent damage to the skeleton-less sealing ring 6 under high pressure, and the pressure on the skeleton-less sealing ring 6 is transmitted radially to the inner wall of the cylinder body 1 through the copper support ring 7 and the inclined surface of the top surface of the skeleton-less sealing ring 6, and is transmitted vertically to the end cover 2, pushing the copper support ring 7 to form radial deformation and keep in contact with the inner wall of the cylinder body 1, ensuring effective support for the skeleton-less sealing ring 6, the skeleton-less sealing ring 6, the copper support ring 7 and the inner wall 1 of the cylinder body are pressed sequentially from the inside to the outside, ensuring the sealing effect, reducing the probability of sealing failure, and extending the sealing life of the end cover of the hot isostatic press.

[0027] Among them, the lower sealing frame assembly 4 includes an annular sealing frame 41 coaxially fixed to the bottom of the cooling cover 3 and a copper sealing ring 42 clamped in the groove of the annular sealing frame 41. There are multiple copper sealing rings 42 and they are in sealing contact with the inner wall of the cylinder body 1 respectively. The annular sealing frame 41 is clamped with multiple annular copper sealing rings 42, and a spring part is provided in the groove of the annular sealing frame 41. The copper sealing ring 42 is clamped in the spring part to ensure that the copper sealing ring 42 is in close contact with the inner wall of the cylinder body in the working state, thereby ensuring the sealing performance; the cooling cover 3 is clamped between the end cover 2 and the annular sealing frame 41, and the copper support ring 7, the cooling cover 3, the annular sealing frame 41 and the inner wall of the cylinder body 1 are surrounded to form an annular cavity A, and the skeleton-free sealing ring 6 is arranged in the annular cavity A. The skeleton-less sealing ring 6 is arranged in the annular cavity A. During installation, the copper support ring 7 is first fitted with the bottom surface of the end cover 2 and the inner wall of the cylinder body 1 to form the annular cavity A, and then the skeleton-less sealing ring 6 is installed. The top surface of the skeleton-less sealing ring 6 is fitted with the copper support ring 7, the inner ring is in contact with the outer wall of the cooling cover 3, and the outer ring is in contact with the inner wall of the cylinder body 1. The installation positions of the skeleton-less sealing ring 6 and the copper support ring 7 are effectively determined, which is convenient for quick installation.

[0028] The frameless sealing ring 6 has an inner lip 61 and an outer lip 62, forming an inverted U-shaped cavity B between the inner lip 61 and the outer lip 62. The inner lip 61 forms a transition fit with the outer wall of the cooling cover 3, while the outer lip 62 forms an interference fit with the inner wall of the cylinder block 1. The transition fit between the inner lip 61 and the cooling cover 3 and the interference fit between the outer lip 62 and the inner wall of the cylinder block 1 allow the frameless sealing ring 6 to be smoothly installed between the cooling cover 3 and the inner wall of the cylinder block 1 without falling downward. The deformation caused by the interference fit imparts radially inward reverse prestress to the frameless sealing ring 6 when not under pressure, thereby improving the pressure-bearing capacity of the frameless sealing ring 6 and reducing the flow deformation of the frameless sealing ring 6 under high-temperature and high-pressure conditions.

[0029] The inner lip 61 has an inner annular surface 8 disposed opposite to the outer wall of the cooling cover 3, and the outer lip 62 has an outer annular surface 9 disposed opposite to the inner wall of the cylinder body 1. The inner annular surface 8 and the outer annular surface 9 are connected by an upper top surface 10. The copper support ring 7 covers the upper top surface 10. The angle between the inner annular surface 8 and the upper top surface 10 is a right angle. The top surface of the copper support ring 7 is in contact with the end cover 2, and the outer wall is in contact with the inner wall of the cylinder body 1. The inner annular surface 8 contacts the outer wall of the cooling cover 3 and has a gap therebetween, while the outer annular surface 9 contacts the inner wall of the cylinder body 1 and has a gap therebetween, making it easier for the boneless sealing ring 6 to be installed in place. At the same time, it also provides space for the compressive deformation flow of the boneless sealing ring 6, effectively reducing the probability of the skeletonless sealing ring being squeezed into the space between the copper support ring 7 and the inner wall of the cylinder body 1 due to deformation flow, thereby reducing the probability of damage to the skeletonless sealing ring 6.

[0030] The outer ring surface 9 and the upper top surface 10 are chamfered to form an inclined upper chamfered surface 11. The bottom of the end cap 2 is provided with a positioning stop 21 with a right-angled cross section for positioning the copper support ring 7. The top surface of the copper support ring 7 fits with the positioning stop 21, and the bottom surface fits with the upper top surface 10 and the upper chamfered surface 11, forming an inclined surface fit between the copper support ring 7 and the top surface of the skeleton-free sealing ring 6. Figure 4 As shown, the upper chamfered surface 11 is inclined to connect the upper top surface 10 and the outer ring surface 9, and the bottom surface of the copper support ring 7 has an inclined surface that fits with the upper chamfered surface 11. The fit between the upper chamfered surface 11 and the inclined surface enables the boneless sealing ring 6 to not only transmit the pressure vertically to the end cover 2 through the copper support ring 7 when it is under pressure, but also transmit the pressure radially to the inner wall of the cylinder 1 through the copper support ring 7. The radial pressure will push the copper support ring 7 to produce radial deformation and expansion, which is consistent with the deformation of the inner wall of the cylinder under high temperature and high pressure, and keep fit with the inner wall of the cylinder 1, ensuring effective support for the skeletonless sealing ring 6. The skeletonless sealing ring 6, the copper support ring 7 and the inner wall of the cylinder 1 It is pressed sequentially from the inside to the outside to ensure the sealing effect, reduce the probability of sealing failure, and extend the sealing life of the end cover of the hot isostatic press; and the inclined setting of the chamfered surface 11 can prevent the skeleton-less sealing ring 6 from squeezing into between the copper support ring 7 and the inner wall of the cylinder body 1, and at the same time also increases the contact area between the copper support ring 7 and the skeleton-less sealing ring 6, thereby improving the supporting capacity of the copper support ring 7 to the skeleton-less sealing ring 6, increasing the initial stiffness and pressure-bearing capacity of the skeleton-less sealing ring 6, reducing the flow deformation of the skeleton-less sealing ring 6, and reducing the probability of the skeleton-less sealing ring 6 forming permanent damage under high pressure, which can effectively extend the sealing life of the skeleton-less sealing ring 6.

[0031] Among them, the inner ring surface 8 is composed of an inner upper ring surface 81 and an inner lower ring surface 82 connected in sequence from top to bottom. The inner upper ring surface 81 is vertically arranged and vertically connected to the upper top surface 10. An angle of 170 degrees to 180 degrees is formed between the inner upper ring surface 81 and the inner lower ring surface 82. The inner lower ring surface 82 and the inner lip bottom surface 63 are transitioned through the inner chamfered surface 83. The angle between the inner chamfered surface 83 and the inner lower ring surface 82 is greater than 90 degrees, and the angle between the inner chamfered surface 83 and the inner lip bottom surface 63 is also greater than 90 degrees. The angle edge of the inner lower ring surface 82 and the inner chamfered surface 83 is in transitional contact with the outer wall of the cooling cover 3, and the inner ring surface 8 is gap-fitted with the outer wall of the cooling cover 3. After the skeleton-less sealing ring 6 is installed in place, the angle edge between the inner lower ring surface 82 and the inner chamfered surface 83 contacts the outer wall of the cooling cover 6, and a gap is formed between the inner upper ring surface 81, the inner lower ring surface 82 and the inner chamfered surface 83 and the outer wall of the cooling end 3, providing flow space for the skeleton-less sealing ring 6 to deform toward the outer wall of the cooling cover 3. At the same time, during the deformation process, the inner upper ring surface 81, the inner lower ring surface 82 and the inner chamfered surface 83 successively fit with the outer wall of the cooling cover 3 to form multiple variable stiffness of the skeleton-less sealing ring 6, so that the stiffness of the skeleton-less sealing ring 6 gradually increases during the deformation process, reduces the deformation speed, effectively reduces the probability of permanent deformation of the skeleton-less sealing ring 6, reduces the probability of sealing failure, and improves sealing reliability.

[0032] Among them, the outer ring surface 9 is composed of an outer upper ring surface 91 and an outer lower ring surface 92 connected in sequence from top to bottom. The outer upper ring surface 91 is connected to the upper chamfered surface 11, and the outer lower ring surface 92 is transitioned to the outer lip bottom surface 64 through the outer chamfered surface 93. The angle between the outer chamfered surface 93 and the outer lower ring surface 92 is greater than 90 degrees, and the angle between the outer chamfered surface 93 and the outer lip bottom surface 64 is also greater than 90 degrees. The angle edge of the outer lower ring surface 92 and the outer chamfered surface 93 is interference fit with the inner wall of the cylinder body 1, and the outer ring surface 9 is clearance fit with the inner wall of the cylinder body 1. After the skeleton-less sealing ring 6 is installed in place, the angle edge between the outer lower segment annular surface 92 and the outer chamfered surface 93 is in interference contact with the inner wall of the cylinder body 1, and gaps are formed between the outer upper segment annular surface 91, the outer lower segment annular surface 92 and the outer chamfered surface 93 and the inner wall of the cylinder body 1, providing flow space for the deformation of the skeleton-less sealing ring 6 toward the inner wall of the cylinder body 1. During the deformation process, the outer upper segment annular surface 91, the outer lower segment annular surface 92 and the outer chamfered surface 93 successively fit with the inner wall of the cylinder body 1 to form multiple variable stiffness of the skeleton-less sealing ring 6, so that the stiffness of the skeleton-less sealing ring 6 gradually increases during the deformation process, reducing the deformation speed, and the angle edge between the outer lower segment annular surface 92 and the outer chamfered surface 93 and the inner wall of the cylinder body 1 are in interference fit to form a reverse prestressing inward in the radial direction. The force is opposite to the pressure that deforms the skeleton-less sealing ring 6 radially outward, which can reduce the deformation speed of the skeleton-less sealing ring 6, improve its pressure-bearing capacity, reduce the probability of the skeleton-less sealing ring 6 squeezing into the space between the inner wall of the cylinder body 1 and the copper support ring 7, and reduce the damage and failure probability of the skeleton-less sealing ring 6; the inner ring surface 8 is in transition fit contact with the outer wall of the cooling end 3, and the outer ring surface 9 is in interference fit contact with the inner wall of the cylinder body 1. Only a small external force is needed to install the skeleton-less sealing ring 6 in place. After the skeleton-less sealing ring 6 is installed in place, it will not form excessive stress deformation, and the initial deformation is small, which is conducive to forming sufficient and effective elastic deformation when subjected to high pressure, reducing the probability of permanent deformation loss and improving sealing reliability.

[0033] The angle between the inner chamfered surface 83 and the inner lip bottom surface 63 is higher than the angle between the outer chamfered surface 93 and the outer lip bottom surface 64. The inverted U-shaped cavity is flared downward, and the flaring angle is 18 to 25 degrees. The inner lower segment annular surface and the outer lower segment annular surface are not parallel, forming a downward flaring angle of 8 to 13 degrees. The angle between the inner chamfered surface 83 and the inner lip bottom surface 63 is higher than the angle between the outer chamfered surface 93 and the outer lip bottom surface 64, which means that the height of the inner lip 61 is less than the height of the outer lip 62. Figure 4 The height difference between the two is H, and the heights of the two lips of the skeleton-free sealing ring 6 are not equal, which can reduce the space occupancy rate of the skeleton-free sealing ring 6 in the annular cavity A, and increase the deformation flow space of the skeleton-free sealing ring 6 in the annular cavity A while ensuring the sealing reliability of the skeleton-free sealing ring 6. At the same time, the inverted U-shaped cavity B is in a downward flaring shape, and the flaring angle is 18 degrees to 25 degrees, that is, Figure 4The angle α between the inner lower segment ring surface 82 and the outer lower segment ring surface 92 is 8-13 degrees. Figure 4 The angle β is 8-13 degrees, which increases the deformation flow space of the skeleton-free sealing ring 6 in the annular cavity A, reduces the extrusion damage probability of the skeleton-free sealing ring 6, and prolongs the service life of the skeleton-free sealing ring 6 on the basis of ensuring the sealing reliability of the skeleton-free sealing ring 6.

[0034] The hot isostatic pressing machine end cover sealing method adopts the hot isostatic pressing machine end cover sealing structure described above for sealing, characterized in that: according to the sealing requirements of the middle end cover of the hot isostatic pressing machine, the sealing performance of the lower sealing frame assembly 4 and the sealing performance of the upper sealing ring assembly 5 are designed, the lower sealing frame assembly 4 and the upper sealing ring assembly 5 form a two-layer sealing structure from bottom to top, and the end cover 2 is sealed; according to the sealing performance of the lower sealing frame assembly 4 and the upper sealing ring assembly 5, the structure of the circulating water channel 31 in the cooling cover 3 and the flow and flow rate of the cooling water in the circulating water channel 31 are designed, so that the working temperature of the lower sealing frame assembly 4 and the upper sealing ring assembly 5 is respectively lower than the upper temperature limit of each. According to the sealing requirements of the end cover, the sealing performance of the lower sealing frame assembly 4 and the upper sealing ring assembly 5 is designed, and a two-layer sealing structure is formed from bottom to top in the cylinder body 1. After determining the sealing performance of the lower sealing frame assembly 4 and the upper sealing ring assembly 5, the structure of the circulating water channel on the cooling cover 3, the flow and flow rate of the cooling water in the circulating water channel are designed, and the lower sealing frame assembly 4 and the upper sealing ring assembly 5 are cooled by the cooling water flow to take away heat and cool down in time, so that the working temperature does not exceed the upper temperature limit set for maintaining the sealing performance. That is, the lower sealing frame assembly 4 and the upper sealing ring assembly 5 are continuously cooled, and the working temperature does not exceed the upper temperature limit set for the sealing performance, avoiding the failure of the lower sealing frame assembly 4 and the upper sealing ring assembly 5 due to high temperature under high temperature and high pressure conditions, and the sealing reliability is high.

[0035] The design of the sealing performance of the upper sealing ring assembly 5 refers to determining the material and hardness of the skeleton-free sealing ring 6, designing the contact area of the skeleton-free sealing ring 6 and the copper support ring 7, and designing the structure of the skeleton-free sealing ring 6, so that the skeleton-free sealing ring 6 pushes the copper support ring 7 to deform radially synchronously to completely fill the radial gap between the cooling cover 3 and the inner wall of the cylinder body 1 during the pressure deformation process of the skeleton-free sealing ring 6, the skeleton-free sealing ring 6 forms pressure on the inner wall of the cylinder body 1 and the end cover 2 through the copper support ring 7, and high-pressure static sealing is realized. By determining the material and hardness of the skeleton-free sealing ring 6, designing the contact area of the skeleton-free sealing ring 6 and the copper support ring 7, and designing the structure of the skeleton-free sealing ring 6, the initial stiffness of the skeleton-free sealing ring 6, the deformation flow and stiffness change process during the pressure deformation process of the skeleton-free sealing ring 6 can be determined, the damage probability of the skeleton-free sealing ring 6 during the pressure deformation process is reduced, the skeleton-free sealing ring 6 pushes the copper support ring 7 to deform radially synchronously to completely fill the radial gap between the cooling cover 3 and the inner wall of the cylinder body 1 during the pressure deformation process of the skeleton-free sealing ring 6, the effectiveness and reliability of the sealing are ensured, the skeleton-free sealing ring 6 forms radial pressure on the inner wall of the cylinder body 1 and vertical pressure on the end cover 2 through the copper support ring 7, the skeleton-free sealing ring 6 bears the impact caused by high gas pressure, the damage failure probability is reduced, and high-pressure static sealing is realized.

[0036] The technical solutions of the embodiments of the application are described in detail above in combination with the drawings. It should be noted that the described embodiments are only some of the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the protection scope of the application.

Claims

1. The end cover sealing structure of the hot isostatic press comprises a cylinder body and an end cover covering the cylinder body, wherein the end cover extends into the cylinder body and a sealing assembly is provided in the cylinder body to seal the end cover, characterized in that: The bottom of the end cover is fixed with a cooling cover for cooling the end cover and a sealing combination. A circulating water channel connected to an external water source and an O-ring sealingly matched with the bottom surface of the end cover are provided on the top surface of the cooling cover. The sealing combination includes a lower sealing frame assembly coaxially fixed to the outer periphery of the cooling cover and in sealing contact with the inner wall of the cylinder body, and an upper sealing ring assembly located above the lower sealing frame assembly. The upper sealing ring assembly includes a frameless sealing ring with an inverted U-shaped cross-section and a copper support ring covering the frameless sealing ring. The inner ring of the frameless sealing ring contacts the outer wall of the cooling cover and a gap is formed therebetween. The outer ring contacts the inner wall of the cylinder body and a gap is also formed therebetween. The copper support ring cooperates with the inclined surface of the top surface of the frameless sealing ring and fits respectively with the inner wall of the cylinder body and the bottom surface of the end cover.

2. The hot isostatic press end cover sealing structure according to claim 1, characterized in that: The lower sealing frame assembly includes an annular sealing frame coaxially fixed to the bottom of the cooling cover and a copper sealing ring clamped in the groove of the annular sealing frame. There are multiple copper sealing rings, which are in sealing contact with the inner wall of the cylinder body respectively. The cooling cover is clamped between the end cover and the annular sealing frame. The copper support ring, cooling cover, annular sealing frame and the inner wall of the cylinder body together form an annular cavity, and the skeleton-free sealing ring is arranged in the annular cavity.

3. The hot isostatic press end cover sealing structure according to claim 2, characterized in that: The skeleton-free sealing ring has an inner lip and an outer lip, an inverted U-shaped cavity is formed between the inner lip and the outer lip, the inner lip is in transition fit contact with the outer wall of the cooling cover, and the outer lip is in interference fit contact with the inner wall of the cylinder body.

4. The hot isostatic press end cover sealing structure according to claim 3, characterized in that: The inner lip has an inner ring surface arranged opposite to the outer wall of the cooling cover, and the outer lip has an outer ring surface arranged opposite to the inner wall of the cylinder body. The inner ring surface and the outer ring surface are connected by the upper top surface. The copper support ring is covered on the upper top surface. The angle between the inner ring surface and the upper top surface is a right angle. The top surface of the copper support ring is in contact with the end cover, and the outer wall is in contact with the inner wall of the cylinder body.

5. The hot isostatic press end cover sealing structure according to claim 4, characterized in that: The outer ring surface and the upper top surface are transitioned by chamfering to form an inclined upper chamfered surface. A positioning stop for positioning the copper support ring and having a right-angled cross-section is provided on the bottom of the end cover. The top surface of the copper support ring is fitted with the positioning stop, and the bottom surface is fitted with the upper top surface and the upper chamfered surface, forming an inclined surface fit between the copper support ring and the top surface of the skeleton-free sealing ring.

6. The hot isostatic press end cover sealing structure according to claim 4, characterized in that: The inner ring surface is composed of an inner upper ring surface and an inner lower ring surface connected in sequence from top to bottom. The inner upper ring surface is vertically arranged and perpendicularly connected to the upper top surface. An angle of 170 degrees to 180 degrees is formed between the inner upper ring surface and the inner lower ring surface. The inner lower ring surface and the bottom surface of the inner lip are transitioned through an inner chamfered surface. The angle between the inner chamfered surface and the inner lower ring surface is greater than 90 degrees, and the angle between the inner chamfered surface and the bottom surface of the inner lip is also greater than 90 degrees. The angle edge between the inner lower ring surface and the inner chamfered surface is in transitional contact with the outer wall of the cooling cover, and the inner ring surface is in clearance fit with the outer wall of the cooling cover.

7. The hot isostatic press end cover sealing structure according to claim 6, characterized in that: The outer ring surface is composed of an outer upper ring surface and an outer lower ring surface connected in sequence from top to bottom. The outer upper ring surface is connected to the upper chamfered surface, and the outer lower ring surface and the bottom surface of the outer lip are transitioned through the outer chamfered surface. The angle between the outer chamfered surface and the outer lower ring surface is greater than 90 degrees, and the angle between the outer chamfered surface and the bottom surface of the outer lip is also greater than 90 degrees. The angle edge between the outer lower ring surface and the outer chamfered surface is interference fit with the inner wall of the cylinder, and the outer ring surface is clearance fit with the inner wall of the cylinder.

8. The hot isostatic press end cover sealing structure according to claim 7, characterized in that: The position of the angle edge between the inner chamfered surface and the bottom surface of the inner lip is higher than the position of the angle edge between the outer chamfered surface and the bottom surface of the outer lip. The inverted U-shaped cavity is in a downward flaring shape, and the flaring angle is 18 degrees to 25 degrees. The inner lower segment annular surface and the outer lower segment annular surface are not parallel, and a downward flaring angle of 8 degrees to 13 degrees is formed between the two.

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