Elastic valve clack for high-temperature sealing and safety valve

Abstract

The invention discloses an elastic valve clack for high-temperature sealing and a safety valve, and relates to the field of safety valves, the elastic valve clack comprises a valve clack body, an annular groove is formed in the surface, facing a valve seat, of the valve clack body, and the outer diameter of the annular groove is not changed firstly and then gradually increased and then gradually decreased in the direction from the surface, facing the valve seat, of the valve clack body to the direction away from the valve seat; the surface, facing the valve seat, of the valve clack body forms a sealing face on the outer side of the annular groove, the sealing face is matched with the valve seat, and the sealing performance of the steam safety valve is improved through the thermal compensation effect of the valve clack structure.

Description

Technical Field

[0001] The present application belongs to the technical field of safety valves, and in particular relates to an elastic valve flap and a safety valve for high-temperature sealing. Background Art

[0002] As the steam pressure equipment in the thermal power and nuclear power industries develops towards high parameters and high safety, higher requirements are placed on the reliability of steam safety valves that play an overpressure protection role. As a key component of the safety valve, the valve disc plays an important role in the sealing and reliability of the safety valve. The integrated elastic valve disc represents the highest level of elastic valve disc technology and is the direction of development of elastic valve disc technology.

[0003] The design concept of the integrated elastic valve disc takes into account both structural strength and sealing characteristics, which can further improve the reliability and stability of safety valve products to respond to the ever-increasing requirements of high-end fields such as electricity and nuclear power. It has important theoretical research significance and engineering application value.

[0004] The existing one-piece elastic valve flap is limited by the processing technology and insufficient technical solutions, and only has an integrated shape in appearance, but the actual valve flap still has the problem of poor sealing during use. Summary of the invention

[0005] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and to provide an elastic valve disc and a safety valve for high-temperature sealing, which can be applied to high-temperature and high-pressure working conditions to meet the requirements for excellent sealing and improve the sealing performance of the steam safety valve.

[0006] The technical solutions provided by this application are as follows:

[0007] An elastic valve flap for high temperature sealing comprises a valve flap body, a surface of the valve flap body facing the valve seat is provided with an annular groove, and along the direction from the surface of the valve flap body facing the valve seat to the direction away from the valve seat, the outer diameter of the annular groove first remains unchanged, then gradually increases and then gradually decreases;

[0008] The surface of the valve disc body facing the valve seat forms a sealing surface outside the annular groove, and the sealing surface cooperates with the valve seat.

[0009] A guide cone is arranged at the middle of the surface of the valve disc body facing the valve seat, and the large diameter end of the guide cone is connected to the end of the annular groove away from the sealing surface.

[0010] A step surface is provided at the edge of the surface of the valve disc body facing the valve seat. The step surface is located on the side of the sealing surface away from the valve seat, and the step surface and the sealing surface are transitioned through a step slope 7. The generatrix of the step slope 7 forms an obtuse angle with the sealing surface.

[0011] Along the direction from the surface of the valve disc body toward the valve seat to the direction away from the valve seat, the part where the outer diameter of the annular groove gradually increases and then gradually decreases forms a straight hole section and a sealing arc, and the inner wall part of the sealing arc is an arc surface.

[0012] The maximum diameter of the arc-shaped surface of the inner wall of the sealing arc is greater than the diameter of the straight hole section.

[0013] The valve flap body is made of elastic material.

[0014] A safety valve comprises: a valve body, a guide sleeve, a bushing, a valve stem and any one of the above-mentioned elastic valve discs for high-temperature sealing, the valve body being provided with an air inlet, an air outlet and a mounting port which are connected to each other, the air inlet being opposite to the mounting port, the valve body being provided with a valve seat at the inner end of the air inlet, the guide sleeve being fixedly installed in the mounting port of the valve body, the bushing being installed on the inner side of the guide sleeve, a circular ring body being connected to the inner wall of the bushing, a valve disc body being installed on the inner side of the bushing, an outer circumferential surface of the valve disc body being in contact with the inner wall of the bushing, a sealing surface of the valve disc body being opposite to the end of the valve seat, and an end of the valve disc body away from the valve seat being in contact with the circular ring body; a valve stem being installed on the valve body, the valve stem being connected to the end of the valve disc body away from the valve seat, and the valve stem applying a thrust to the valve disc body in the direction of the valve seat.

[0015] A plurality of outer annular grooves are arranged on the outer circumference of the valve flap body.

[0016] The end of the valve flap body away from the valve seat is provided with a mounting groove, the bottom of the mounting groove is provided with a spherical guide ball socket, and the end of the valve stem is matched with the guide ball socket.

[0017] The elastic valve flap of the present invention is used for high temperature sealing. The elastic valve flap is an integrated structure and is applied to steam safety valves under high temperature and high pressure working conditions. The working pressure has exceeded 35MPa. The elastic valve flap sealing structure with integrated multi-factor design has undergone a unique heat treatment process. The valve flap sealing lip relies on elastic deformation to meet the sealing requirements of long-term application under high temperature and high pressure harsh working conditions, which can improve the overall reliability of the steam safety valve.

[0018] The developed valve disc sealing performance and action performance meet the requirements of Volume I of ASME "Boiler and Pressure Vessel Code"; overpressure ≤3% of set pressure, opening and closing pressure difference ≤4% of set pressure; the continuous take-off action performance and sealing performance of the safety valve under hot test still meet the standard requirements.

[0019] In summary, this application at least includes the following beneficial technical effects:

[0020] Through the design of the elastic valve disc structure, the present invention has the following effects: the designed sealing lip structure can ensure good sealing at 96% of the set pressure in the hot test; the steam safety valve using the valve disc has no flutter and blocking phenomenon during operation, the overpressure is ≤3% of the set pressure, and the opening and closing pressure difference is ≤4% of the set pressure, which meets the requirements of Volume I of ASME "Boiler and Pressure Vessel Code"; the continuous starting action performance and sealing performance of the safety valve in the hot test can still ensure good sealing at 96% of the set pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the overall structure of the elastic valve disc;

[0022] Figure 2 Schematic diagram of rigid valve disc structure;

[0023] Figure 3 Schematic diagram of sealing lip structure;

[0024] Figure 4 Schematic diagram of valve disc force;

[0025] Figure 5 This is the overall diagram of the safety valve.

[0026] Explanation of the reference numerals: 1. Sealing arc; 2. Sealing lip; 3. Guide cone; 4. Guide ball socket; 5. Outer ring groove; 6. Sealing surface; 7. Step slope;

[0027] 81. Valve body; 82. Valve cover; 83. Guide sleeve; 84. Bushing; 85. Valve stem; 86. Spring; 87. Valve disc body. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] The present application embodiment discloses an elastic valve flap for high temperature sealing, such as Figure 1 and Figure 3 As shown, it includes a valve flap body 87. The valve flap body 87 is made of an elastic material, for example, a nickel-based alloy material suitable for high temperatures. An annular groove is provided on the surface of the valve flap body 87 facing the valve seat. Along the direction from the surface of the valve flap body facing the valve seat to the direction away from the valve seat, the outer diameter of the annular groove first remains unchanged, then gradually increases and then gradually decreases, forming a straight hole section and a sealing arc 1. The inner wall portion of the sealing arc 1 is an arc surface, and the maximum diameter of the arc surface of the inner wall of the sealing arc 1 is greater than the diameter of the straight hole section. Along the direction away from the axis of the valve flap body, there is a portion where the distance from the sealing surface 6 to the inner wall of the sealing arc 1 gradually increases, and this portion is the sealing lip 2. The surface of the valve flap body facing the valve seat forms a sealing surface 6 on the outside of the annular groove, and the sealing surface 6 cooperates with the valve seat.

[0030] A guide cone 3 is provided in the middle of the surface of the valve disc body 87 facing the valve seat, and the large diameter end of the guide cone 3 is connected to the end of the annular groove away from the sealing surface 6, and the cone angle of the guide cone 3 is 60°-120°. The guide cone 3 guides the steam flowing from the valve seat to the valve disc, so that the steam directly enters the sealing arc 1 along the cone surface of the guide cone 3. Since the sealing arc 1 is an arc surface, the steam generates a uniform pressure on the inner wall of the sealing arc 1, so that the sealing lip 2 is compressed and pressed toward the valve seat, that is, the inner side of the sealing surface 6 is pressed against the valve seat, and the outer side of the sealing surface 6 is slightly lifted. Since the sealing specific pressure = sealing force / sealing area, the above process reduces the sealing area, so the seal is tighter.

[0031] A stepped surface is provided at the edge of the surface of the valve disc body facing the valve seat. The stepped surface extends from the outer side of the sealing surface 6 to the circumferential surface of the valve disc body. The stepped surface is located on the side of the sealing surface 6 away from the valve seat, and the stepped surface and the sealing surface 6 are transitioned through a stepped slope 7. Along the radial direction of the valve disc body and away from the axis of the valve disc body, the stepped slope 7 gradually approaches the stepped surface from the outer edge of the sealing surface 6. When the sealing lip 2 "tiptoe" due to the pressure deformation of the steam medium inside the sealing arc 1, the setting of the stepped slope 7 and the stepped surface increases the flexibility of the sealing lip, so that the sealing lip 2 can have a larger deformation amount and is more likely to "tiptoe".

[0032] A mounting groove is provided at the end of the valve flap body 87 away from the valve seat, and the end of the valve stem is installed in the mounting groove. A spherical guide ball socket 4 is provided at the bottom of the mounting groove. The guide ball socket 4 is used to cooperate with the valve stem head. An outer ring groove 5 is provided on the outer circumferential surface of the valve flap body.

[0033] After the sealing surface 6 contacts the valve seat sealing surface of the safety valve, the safety valve is closed to achieve a sealing effect. When the safety valve is closed, the structure of the steam medium is the sealing arc 1, the sealing lip 2, and the guide cone 3. After the safety valve is opened, in addition to the above three parts, the guide ball socket 4 and the outer ring groove 5 will also contact the steam medium. The opening and closing process of the safety valve is short, which is extremely challenging to the reliability of the valve disc sealing structure.

[0034] When the safety valve is closed, it is subjected to the vertical downward spring force and the medium force in the normal direction, and the forces eventually reach a balanced state. The pressure generated by the medium in the sealing arc 1 will evenly act on the sealing surface 6 of the valve disc. The sealing lip 2 has extremely high elasticity. As the operating pressure and temperature continue to increase, the elastic structure produces a thermal compensation effect of structural deformation to ensure the good sealing performance of the safety valve. When the steam medium pressure is higher than the spring force, the safety valve opens. The sealing lip 2 structure of the valve disc returns to its original shape due to its elasticity. The medium flows through the guide cone 3, the sealing surface 6, and then through the outer ring groove 5. The steam medium flows through the gap all the way to the upper structure of the safety valve. After the medium is discharged, the spring force is greater than the medium force and the safety valve returns to its seat. The sealing lip 2 of the valve disc begins to play a role. The medium acts on the inner surface of the arc, and the inner surface of the arc is pushed downward by the pressure of the system medium. The valve has a good sealing effect under operating conditions.

[0035] The sealing arc 1 and the sealing lip 2 are the sealing structure of the elastic valve disc, the guide cone 3 is the guide structure of the elastic valve disc, the guide ball socket 4 is the guide structure of the elastic valve disc, and the outer ring groove 5 is the stabilization structure of the elastic valve disc. The elastic valve disc is an integrated hollow structure, and the sealing arc 1, the sealing lip 2, and the guide cone 3 of the lower half of the elastic valve disc contact the steam medium; the stepped slope 7 of the sealing lip 2 serves as a transition zone when the sealing lip 2 undergoes elastic deformation, and the sealing surface 6 plays a sealing role by contacting the valve seat of the safety valve; the guide ball socket 4 contacts the head of the safety valve stem, so that the spring transmits force evenly; the outer ring groove 5 is a groove opened on the outer circumferential surface of the valve disc body.

[0036] like Figure 4 As shown, under the structure of this patent, when the valve disc body is elastic, its force is evenly distributed on the sealing lip, and the deformation of the sealing lip plays a buffering role on the impact force generated when the sealing surface contacts the valve seat; Figure 2 As shown, under the structure of this patent, when the valve disc body is rigid, the sealing surface is subjected to force in the vertical direction. Since there is no thermal deformation, it cannot play a buffering role on the sealing structure.

[0037] As a comparison, Figure 2 As shown, since the conventional rigid valve flap cannot produce elastic deformation after being heated and cannot provide thermal compensation, the core of this patent is to replace the conventional rigid valve flap with an elastic valve flap with high-temperature elastic deformation and thermal compensation function. The material is a nickel-based alloy suitable for high-temperature and high-pressure working conditions. When the pressure increases or the temperature rises, the deformation of the sealing structure enhances the reliability of the sealing surface contact, compensates for the possible pre-discharge of the steam safety valve, improves the opening accuracy and sealing effect of the safety valve, and optimizes the reliable and stable performance of the steam safety valve.

[0038] The patent of this invention has the following obvious features:

[0039] The valve disc is an integrated structure.

[0040] The design of the guide ball socket 4 makes the spring force uniform.

[0041] The outer side of the valve disc is provided with a plurality of outer ring grooves 5.

[0042] The valve flap has a guide cone 3 structure.

[0043] The key technologies of the elastic valve disc structure are three points:

[0044] 1. The design of the integrated elastic disc structure relies on its own elastic deformation to maintain the sealing performance of the safety valve at 96% of the set pressure.

[0045] 2. The contact between the guide ball socket 4 and the head of the valve stem can balance the pressure and ensure the sealing performance.

[0046] 3. Structural design of the outer ring groove 5.

[0047] This embodiment also discloses a safety valve, such as Figure 5 As shown, it includes a valve body 81, a valve cover 82, a guide sleeve 83, a bushing 84, a valve stem 85, an elastic member, and the above-mentioned valve disc body 87.

[0048] The valve body 81 is provided with an interconnected air inlet, an air outlet and an installation port. The air inlet is opposite to the installation port. The valve body 81 is provided with a valve seat at the inner end of the air inlet. The guide sleeve 83 is fixedly installed in the installation port of the valve body 81. The guide sleeve 83 is a cylindrical structure with openings at both ends. The bushing 84 is installed on the inner side of the guide sleeve 83 and there is a gap between the guide sleeve 83. The bushing 84 is a cylindrical structure with openings at both ends. The inner wall of the bushing 84 is connected to a circular ring.

[0049] The valve flap body 87 is installed on the upper end of the bushing 84, the outer circumferential surface of the valve flap body 87 contacts the inner wall of the bushing 84, the sealing surface 6 of the valve flap body 87 faces the end of the valve seat, and the end of the valve flap body 87 away from the valve seat contacts the annular body.

[0050] The valve cover 82 is installed at the upper end of the installation port of the valve body 81, and the valve stem 85 is slidably connected relative to the valve cover 82 along the axial direction of the air inlet. The elastic member is a spring 86, and the spring 86 is installed on the outside of the valve stem 85 to give the valve stem 85 a thrust to move toward the valve seat. The valve stem 85 extends into the valve body 81 and cooperates with the guide ball socket 4 of the valve disc body 87, so that the valve stem 85 can push the valve disc body 87 to move.

[0051] The end of the valve cover 82 facing the valve body 81 is sealed with the end of the guide sleeve 83. The valve cover 82 is provided with a first through hole and a second through hole. The first through hole and the second through hole are both connected to the inner space of the guide sleeve 83 at one end and connected to the outer wall of the valve cover 82 at the other end. The first through hole and the second through hole are connected to different positions of the outer wall of the valve cover 82. The end of the first through hole of the valve cover 82 is internally threaded with a bolt.

[0052] Due to the setting of the outer ring groove 5, when the valve flap body 87 and the valve seat are opened, the steam will pass through the surface of the guide cone 3, the sealing arc 1, and the sealing surface 6 at one time, and then enter between the valve flap body 87 and the bushing 84, so that steam will be stored in the outer ring groove 5, which makes the valve flap body 87 and the bushing 84 float relatively, reduces friction, and is not easy to get stuck.

[0053] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0054] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. An elastic valve flap for high temperature sealing, characterized in that: It comprises a valve flap body (87), wherein a surface of the valve flap body (87) facing the valve seat is provided with an annular groove, and along a direction from the surface of the valve flap body facing the valve seat to a direction away from the valve seat, the outer diameter of the annular groove first remains unchanged, then gradually increases, and then gradually decreases; The surface of the valve disc body facing the valve seat forms a sealing surface (6) at the outer side of the annular groove, and the sealing surface (6) cooperates with the valve seat.

2. The elastic valve flap for high temperature sealing according to claim 1, characterized in that: A guide cone (3) is provided in the middle of the surface of the valve disc body (87) facing the valve seat, and the large diameter end of the guide cone (3) is connected to the end of the annular groove away from the sealing surface (6).

3. The elastic valve flap for high temperature sealing according to claim 1, characterized in that: A stepped surface is provided at the edge of the surface of the valve flap body facing the valve seat, the stepped surface is located on the side of the sealing surface (6) away from the valve seat, and a stepped slope 7 transitions between the stepped surface and the sealing surface (6), with a generatrix of the stepped slope 7 forming an obtuse angle with the sealing surface (6).

4. The elastic valve flap for high temperature sealing according to claim 1, characterized in that: Along the direction from the surface of the valve flap body toward the valve seat to the direction away from the valve seat, the part where the outer diameter of the annular groove gradually increases and then gradually decreases forms a straight hole section and a sealing arc (1), and the inner wall part of the sealing arc (1) is an arc surface.

5. The elastic valve flap for high temperature sealing according to claim 4, characterized in that: The maximum diameter of the arc-shaped surface of the inner wall of the sealing arc (1) is greater than the diameter of the straight hole section.

6. The elastic valve flap for high temperature sealing according to claim 1, characterized in that: The valve flap body (87) is made of elastic material.

7. A safety valve, characterized in that: include: A valve body (81), a guide sleeve (83), a bushing (84), a valve stem (85) and an elastic valve disc for high temperature sealing as described in any one of claims 1 to 6, wherein the valve body (81) is provided with an air inlet, an air outlet and a mounting port which are connected to each other, the air inlet is opposite to the mounting port, the valve body (81) is provided with a valve seat at the inner end of the air inlet, the guide sleeve (83) is fixedly installed in the mounting port of the valve body (81), the bushing (84) is installed on the inner side of the guide sleeve (83), and the inner wall of the bushing (84) is A circular ring body is connected, the valve flap body (87) is installed on the inner side of the bushing (84), the outer circumferential surface of the valve flap body (87) contacts the inner wall of the bushing (84), the sealing surface (6) of the valve flap body (87) faces the end of the valve seat, and the end of the valve flap body (87) away from the valve seat contacts the circular ring body; the valve stem (85) is installed on the valve body (81), the valve stem (85) is connected to the end of the valve flap body (87) away from the valve seat, and the valve stem (85) gives the valve flap body (87) a thrust in the direction of the valve seat.

8. The safety valve according to claim 7, characterized in that: A plurality of outer annular grooves (5) are arranged on the outer circumference of the valve flap body (87).

9. The safety valve according to claim 7, characterized in that: The end of the valve disc body (87) away from the valve seat is provided with a mounting groove, the bottom of the mounting groove is provided with a spherical guide ball socket (4), and the end of the valve stem (85) cooperates with the guide ball socket (4).

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