Stop valve with double valve cores and valve seats and sealing method

Abstract

The invention discloses a stop valve with a double-valve-element valve seat and a sealing method, and belongs to the technical field of high-medium-low-pressure pipeline conveying. The stop valve comprises a valve body, a hand wheel, a transmission mechanism, a valve rod and a sealing mechanism, a mounting hole and two inlet and outlet holes communicated with the mounting hole respectively are formed in the valve body, the sealing mechanism comprises a first valve seat, a first valve element, a valve element transmission assembly, a second valve element and a second valve seat which are sequentially connected, the hand wheel is connected with the head end of the valve rod, and the tail end of the valve rod is connected with the first valve element. When the valve rod pushes the first valve element to move towards the tail end, the second valve element moves towards the head end, the two valve elements leave the valve seat respectively so as to conduct the two inlet and outlet holes, when the valve rod drives the first valve element to move towards the head end, the second valve element moves towards the tail end, and the two valve elements make contact with the sealing face of the valve seat in a sealed mode respectively so as to isolate the two inlet and outlet holes. Two groups of sealing surfaces are formed through the sealing mechanism, double sealing is achieved, the sealing effect is improved, and normal work of the whole system is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of high, medium and low pressure pipeline transportation, and in particular relates to a stop valve with a double valve core and valve seat and a sealing method. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] In industrial production and fluid delivery systems, the stop valve is a key control component, widely used in many fields such as petroleum, chemical industry, electric power, water supply and drainage, etc.

[0004] With the development of industry, the requirements for automation and continuity of production processes are getting higher and higher, and the frequency of use and working time of stop valves are also increasing accordingly. Frequent switching operations and long-term operating conditions make the valve core seal face more severe tests, such as increased wear of the valve core and valve seat, aging of sealing materials, etc., which may lead to a decrease in sealing performance, thus affecting the normal use of the stop valve and the stable operation of the entire system.

[0005] The existing stop valve has a so-called single valve core and valve seat seal, and the valve core is a single compression seal. If there are hard particles in the medium that squeeze on the valve core and valve seat sealing surface, it will cause the valve core and valve seat to be scratched, resulting in leakage risks; frequent opening and closing can easily cause the valve core and valve seat to wear and cause leakage and other problems. During use, if leakage occurs due to valve core wear and other reasons, once the leakage occurs, the stop valve will not work properly, which will affect the normal operation of the entire system, and the stability and reliability will be low, and the service life will be short.

[0006] Therefore, how to provide a stop valve with excellent sealing effect, stability and reliability, and long service life is a technical problem that technical personnel in this field currently need to solve. Summary of the invention

[0007] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a stop valve with a double valve core and valve seat and a sealing method. During the opening and closing process of the stop valve provided by the present invention, the double valve cores move synchronously and the double valve core and valve seat are used for sealing, which has a good sealing effect.

[0008] In order to achieve the above object, the technical solution of the present invention is:

[0009] The first aspect of the present invention provides a stop valve with a double valve core and valve seat, including a valve body, a handwheel, a transmission mechanism, a valve stem and a sealing mechanism, wherein a mounting hole is provided in the valve body, and two inlet and outlet holes respectively connected to the mounting hole are provided in the valve body, and the sealing mechanism is arranged in the mounting hole, including a first valve seat, a first valve core, a valve core transmission assembly, a second valve core and a second valve seat connected in sequence, the handwheel is connected to the head end of the valve stem through the transmission mechanism, and the end of the valve stem is connected to the first valve core, when the valve stem pushes the first valve core to move in the direction of the second valve core, the second valve core moves in the direction of the first valve core under the drive of the valve core transmission assembly, and the two valve cores leave the valve seats respectively to connect the two inlet and outlet holes, the valve stem drives the first valve core to move in the direction away from the second valve core, and the second valve core moves in the direction away from the first valve core under the drive of the valve core transmission assembly, and the two valve cores respectively seal and contact the sealing surface of the valve seat to isolate the two inlet and outlet holes.

[0010] In some embodiments of the present invention, the mounting hole extends along the axis of the stop valve, and the openings of the two inlet and outlet holes connected to the side walls of the mounting hole are staggered in the axial direction.

[0011] In some embodiments of the present invention, the valve core transmission assembly includes a first connecting rod, a second connecting rod, a transmission wheel and a transmission shaft. The transmission wheel is sleeved on the transmission shaft and rotates around the transmission shaft. The first connecting rod and the second connecting rod are arranged on both sides of the transmission wheel. The rotation of the transmission wheel drives the first connecting rod and the second connecting rod to move in opposite directions. The transmission shaft is connected to the valve body.

[0012] In some embodiments of the present invention, the first connecting rod and the transmission wheel, as well as the second connecting rod and the transmission wheel are both driven by rack and pinion.

[0013] In some embodiments of the present invention, a sealing device is further provided in the valve body, which is sleeved on the outside of the valve stem and arranged in the mounting hole above the sealing mechanism.

[0014] In some embodiments of the present invention, the sealing device is a valve stem sealing ring.

[0015] In some embodiments of the present invention, a valve stem thrust mechanism is provided at the end of the valve stem, and the end of the valve stem thrust mechanism is fixedly connected to the first valve core. The valve stem thrust mechanism is composed of three cylinders with different diameters fixed in order of decreasing diameters, and the centers of the bottom circles of the three cylinders are on the same straight line. The cylinder with the largest diameter is connected to the end of the valve stem, and its diameter is the diameter of the mounting hole. The diameters of the remaining two cylinders are smaller than the diameter of the through hole in the first valve seat, and the cylinder with the smallest diameter is connected to the first valve core.

[0016] Preferably, the cylinder with the smallest diameter is embedded in the first valve core.

[0017] In some embodiments of the present invention, the stop valve further comprises a valve cover, which is arranged above the valve body and fixedly connected to the valve body, the valve stem passes through the valve cover and is connected to the transmission mechanism, and a groove for installing the transmission mechanism is provided on the top of the valve cover;

[0018] The transmission mechanism includes a driving nut, a driving bearing and a bearing pressure cover. A part of the driving nut is arranged in a groove on the top of the valve cover and is sleeved on the head end of the valve stem, and a part is fixedly connected to the handwheel. The driving bearing is arranged in the groove and sleeved on the driving nut. The bearing pressure cover is arranged on the driving nut and is arranged on the top of the valve cover to fix the driving bearing. The handwheel, the driving nut and the driving bearing cooperate so that the driving nut can move up and down in the groove by rotation.

[0019] In some embodiments of the present invention, the valve cover and the valve body are fixed by bolts.

[0020] A second aspect of the present invention provides a sealing method, using the above-mentioned stop valve to connect the pipeline to the inlet and outlet holes, turning the hand wheel to drive the valve stem to move upward, the first valve core seals the first valve seat upward, and the second valve core seals the second valve seat downward, the two inlet and outlet holes are isolated, and sealing is achieved; turning the hand wheel to drive the valve stem to move downward, the first valve core moves downward and leaves the first valve seat, the second valve core moves upward and leaves the valve seat, the two inlet and outlet holes are connected, and communication is achieved.

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides a stop valve sealing method with double valve core and valve seat sealing, and provides a double valve core and valve seat sealing structure with synchronous movement to improve the sealing reliability inside the stop valve. During the opening and closing process of the stop valve, the double valve core moves synchronously, and the double valve core and valve seat are sealed, with good sealing effect. If a valve core and valve seat are worn and leak, the sealing mechanism of the other valve core and valve seat can still maintain the sealing effect, and the fault tolerance rate is high. The stop valve sealing method with double valve core and valve seat sealing improves the sealing effect inside the stop valve and the fault tolerance rate of medium transportation, solves the problem of leakage caused by valve core and valve seat wear during the use of the existing stop valve, ensures the safety of valve use and production safety, and improves the production operation efficiency.

[0023] When the stop valve with double valve core and valve seat sealing provided by the present invention is closed or the second valve core and valve seat is damaged, the first valve core and valve seat are self-sealing, and become tighter with the pressure of the medium, so the sealing effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 This is a schematic structural diagram of a stop valve with double valve core and valve seat sealing according to Example 1 of the present invention;

[0026] Figure 2 for Figure 1 Enlarged view of part A.

[0027] In the figure, 1-valve body; 2-second valve seat; 3-second valve core; 4-second connecting rod; 5-transmission wheel; 6-transmission shaft; 7-first connecting rod; 8-first valve core; 9-first valve seat; 10-valve stem thrust mechanism; 11-valve stem sealing ring; 12-valve cover; 13-valve stem; 14-drive nut; 15-drive bearing; 16-bearing pressure cover; 17-handwheel; 18-mounting hole, 19-inlet and outlet holes. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0029] See also Figure 1 and Figure 2 ,in, Figure 1 Schematic diagram of the structure of the double valve core valve seat in this embodiment. Figure 2 for Figure 1 An enlarged view of part A in the structural schematic diagram shown.

[0030] A typical embodiment of the present invention provides a stop valve with a double valve core and valve seat, such as Figure 1 As shown, the stop valve with double valve core and valve seat includes a valve body 1, a hand wheel 17, a transmission mechanism, a valve stem 13 and a sealing mechanism. The end of each component close to the hand wheel 17 is defined as the head end, and the end close to the valve body 1 is defined as the tail end. The head end and the tail end of the valve body 1 are also extended with other components. In the contents shown in each figure, the upper end is the head end and the lower end is the tail end. The valve body 1 is provided with a mounting hole 18, which extends axially, with the head end opening located at the head end face of the valve body 1, and the tail end opening is closed and located at the lower part of the valve body 1. At the same time, the valve body 1 is also provided with two inlet and outlet holes 19 respectively connected to the mounting hole 18, the inner end ports of the two inlet and outlet holes 19 are connected to the mounting hole 18, the outer end ports of the two inlet and outlet holes 19 are arranged on opposite sides of the outer periphery of the valve body 1, and the outer end openings of the two inlet and outlet holes 19 are used to connect the liquid inlet pipe and the liquid outlet pipe. When the liquid flows, it flows through the liquid inlet pipe, one inlet and outlet hole 19, the mounting hole 18, the other inlet and outlet hole 19 and the liquid outlet pipe in sequence.

[0031] The sealing mechanism is arranged in the mounting hole 18, and includes a first valve seat 9, a first valve core 8, a valve core transmission assembly, a second valve core 3 and a second valve seat 2 which are connected in sequence. The sealing mechanism is arranged in the mounting hole 18, and the sealing mechanism is arranged between the inner end openings of the two inlet and outlet holes 19, and is an important component for isolating the two inlet and outlet holes 19. The diameters of the first valve seat 9 and the second valve seat 2 are the same as the diameter of the mounting hole 18. The two valve seats are fixed in the mounting hole 18, and through holes are provided at the center positions of the two valve seats to facilitate the flow of liquid. The diameters of the two valve cores are both larger than the diameters of the through holes to seal the valve seats and ensure excellent sealing effects. The valve core transmission assembly can make the two valve cores move synchronously in opposite directions to improve the sealing effect.

[0032] The hand wheel 17 is connected to the head end of the valve stem 13 through the transmission mechanism, and the end of the valve stem 13 is connected to the first valve core 8. When the hand wheel 17 is turned forward, the valve stem 13 is driven to move axially toward the end through the transmission mechanism. Further, when the valve stem 13 pushes the first valve core 8 to move toward the second valve core 3, the second valve core 3 moves toward the first valve core 8 under the drive of the valve core transmission assembly, and the two valve cores leave the valve seat respectively to connect the two inlet and outlet holes 19. When the hand wheel 17 is turned reversely, the valve stem 13 is driven to move axially toward the head end through the transmission mechanism. Further, the valve stem 13 drives the first valve core 8 to move away from the second valve core 3. Under the drive of the valve core transmission assembly, the second valve core 3 moves away from the first valve core 8. The two valve cores are sealed and contact the sealing surface of the valve seat respectively, forming two sets of sealing surfaces to isolate the two inlet and outlet holes 19.

[0033] Two sets of sealing surfaces are formed by the first valve seat 9 and the first valve core 8, the second valve seat 2 and the second valve core 3 to achieve double sealing of the stop valve. Compared with the single sealing of the traditional stop valve, if a valve core valve seat has a wear and leakage problem, the other valve core valve seat can still maintain the sealing effect, and the fault tolerance rate is high. And any valve core valve seat in the double valve core valve seat structure is self-sealing. If the second valve core 3 is worn and leaked, the liquid medium in the liquid outlet pipe enters the mounting hole 18, providing a certain pressure for the first valve core 8, and improving the sealing effect. If the first valve core 8 is worn and leaked, the liquid medium in the liquid inlet pipe enters the mounting hole 18 and is stored above the second valve core 3, providing a certain pressure for the second valve core 3, and improving the sealing effect. It can be seen that the sealing method of the stop valve with double valve core valve seat sealing improves the sealing effect and liquid medium transportation fault tolerance of the stop valve, solves the problem of leakage caused by the wear of the valve core valve seat during the use of the existing stop valve, ensures the safety of valve use and production safety, and improves production operation efficiency.

[0034] In some embodiments of this embodiment, the mounting hole 18 extends along the axis of the stop valve, the inner end openings of the two inlet and outlet holes 19 connected to the side wall of the mounting hole 18 are staggered along the axial direction, and the sealing mechanism is located between the two openings, so that the liquid flowing through the stop valve must flow through the sealing mechanism. Specifically, the two inlet and outlet holes 19 can extend radially completely perpendicular to the axial direction, and the outer end openings of the two inlet and outlet holes 19 are also staggered and not in the same straight line. The two inlet and outlet holes 19 may also not extend radially completely perpendicular to the axial direction, and the inlet and outlet hole 19 located above may be tilted downward, and the inlet and outlet hole 19 located below may be tilted upward, so that the outer end openings of the two inlet and outlet holes 19 are in the same straight line, making the installation of the stop valve more convenient and the layout more reasonable.

[0035] In some embodiments of this implementation mode, the valve core transmission assembly includes a first connecting rod 7, a second connecting rod 4, a transmission wheel 5 and a transmission shaft 6, the transmission wheel 5 is sleeved on the transmission shaft 6 and rotates around the transmission shaft 6, the first connecting rod 7 and the second connecting rod 4 are arranged on both sides of the transmission wheel 5, and the rotation of the transmission wheel 5 drives the first connecting rod 7 and the second connecting rod 4 to move in opposite directions, and the transmission shaft 6 is connected to the valve body 1.

[0036] It should be noted that the first connecting rod 7, the second connecting rod 4, the transmission wheel 5 and the transmission shaft 6 together constitute a valve core transmission assembly, and the first connecting rod 7 and the second connecting rod 4 are driven by the transmission wheel 5 to achieve synchronous operation. The first connecting rod 7, the second connecting rod 4 and the transmission wheel 5 can be connected by a variety of transmission methods, such as a gear rack transmission method, or a crank connecting rod transmission.

[0037] like Figure 2 As shown, the first connecting rod 7, the second connecting rod 4 and the transmission wheel 5 are transmitted by a gear rack. The transmission wheel 5 is a gear, which is sleeved on the transmission shaft 6 and rotates around the transmission shaft 6. A rack is provided on the contact surface of the first connecting rod 7 and the second connecting rod 4 with the transmission wheel 5. When the transmission wheel 5 rotates, the first connecting rod 7 and the second connecting rod 4 are driven to move in opposite directions through the meshing of the gear rack. Specifically, when the first connecting rod 7 is pushed downward by the valve stem 13, the transmission wheel 5 is driven to rotate around the transmission shaft 6, and the second connecting rod 4 is moved upward by the meshing of the gear rack, and the two valve cores leave the sealing surface of the valve seat to achieve conduction. When the first connecting rod 7 is pulled upward by the valve stem 13, the transmission wheel 5 is driven to rotate around the transmission shaft 6, and the second connecting rod 4 is moved downward by the meshing of the gear rack, and the two valve cores seal the sealing surface of the valve seat to achieve sealing, thereby achieving valve closure.

[0038] It should be noted that the first connecting rod 7, the second connecting rod 4 and the transmission wheel 5 can also be transmitted through a crank-connecting rod mechanism, and the valve core is driven downward or upward by the first connecting rod 7, the second connecting rod 4 and the transmission wheel 5 to achieve double sealing.

[0039] In some examples of this implementation, a sealing device is further provided in the valve body, which is sleeved on the outside of the valve stem 13 and is arranged in the mounting hole 18 above the sealing mechanism. Specifically, the sealing device is a valve stem sealing ring 11. The valve stem sealing ring 11 is sleeved on the outside of the valve stem 13, and the valve stem sealing ring 11 is located between the inner end opening of the upper inlet and outlet hole 19 and the top of the valve body 1, and the top of the valve stem sealing ring 11 is flush with the top of the valve body 1 to prevent the liquid medium from flowing out of the top of the valve body 1 through the gap between the valve stem 13 and the valve body 1. The valve stem sealing ring 11 can be made of rubber, polytetrafluoroethylene, graphite and other materials. Different materials have different temperature resistance, wear resistance and corrosion resistance. It is necessary to select a suitable material according to the working environment and use requirements.

[0040] In some examples of this embodiment, a stem thrust mechanism 10 is provided at the end of the valve stem 13, and the end of the stem thrust mechanism 10 is fixedly connected to the first valve core 8. It can be understood that the stem thrust mechanism 10 is used to withstand the thrust of the valve stem 13, drive the first valve core 8 to move up and down, and can also prevent the liquid medium from entering the gap between the valve stem 13 and the valve body sealing ring 11, thereby preventing the liquid medium from leaking from the top of the valve body 1 and improving the sealing effect.

[0041] The valve stem thrust mechanism 10 is composed of two parts, one part is a cylinder connected to the valve stem 13 and having a diameter equal to the diameter of the mounting hole 18, which is used to prevent the liquid medium from leaking from the top of the valve body 1, and the other part is a thrust rod installed below the cylinder, the diameter of the thrust rod is smaller than the diameter of the mounting hole 18, and the diameter of the end connected to the first valve core 8 is smaller than the diameter of the through hole on the valve body. The present invention does not limit the shape of the thrust rod, as long as it can transmit the force of the valve stem 13. For example, the thrust rod can be cylindrical, and the center of its bottom surface is on the same vertical line as the center of the bottom surface of the cylinder. In order to improve the strength of the thrust rod and prevent it from being damaged due to excessive force, the thrust rod can be cake-shaped, which can be composed of a plurality of cylinders of different diameters stacked from top to bottom in the order of diameter from high to low.

[0042] like Figure 1As shown, the valve stem thrust mechanism 10 is composed of three cylinders of different diameters fixed from top to bottom in the order of decreasing diameters, the centers of the bottom circles of the three cylinders are on the same vertical line, and the centers of the bottom circles of the three cylinders and the center of the bottom circle of the valve stem 13 are also on the same straight line, that is, the valve stem thrust mechanism 10 is coaxially arranged with the valve stem 13. The cylinder with the largest diameter is connected to the end of the valve stem 13, and its diameter is the diameter of the mounting hole 18. The diameters of the remaining two cylinders are smaller than the diameters of the through holes in the first valve seat 9, and the cylinder with the smallest diameter (i.e., the end of the valve stem thrust mechanism 10) is connected to the first valve core 8 to transmit the force of the valve stem 13 to the first valve core 8.

[0043] It can be understood that the valve stem thrust mechanism 10 and the valve stem 13 are integrally formed, and the diameter of the connecting portion of the valve stem thrust mechanism 10 and the valve 13 is enlarged to the diameter of the mounting hole 18 to prevent the liquid medium from entering the gap between the valve stem 13 and the valve body sealing ring 11, thereby leaking from the top of the valve body 1.

[0044] It can be understood that in order to avoid deformation, deviation and other problems of the first valve core 8 when the thrust rod pushes the first valve core 8 to move downward, the cylinder with the smallest diameter (i.e., the end of the valve stem thrust mechanism 10) is located directly above the center of gravity of the first valve core 8. In order to improve the transmission effect and the connection strength between the valve stem thrust mechanism 10 and the first valve core 8, the cylinder with the smallest diameter (i.e., the end of the valve stem thrust mechanism 10) can be embedded in the first valve core 8, and the connection strength and force transmission effect can be improved by increasing the contact area between the valve stem thrust mechanism 10 and the first valve core 8.

[0045] In some embodiments of the present invention, the stop valve further includes a valve cover 12, and the functions of the valve cover 12 are: sealing the valve body 1, pressing the valve stem sealing ring 11, and preventing the liquid medium from leaking from the top of the valve body 1; positioning the valve stem 13, and ensuring the normal transmission of the valve stem 13. The valve cover 12 is arranged above the valve body 1 and is fixedly connected to the valve body 1. The valve stem 13 passes through the valve cover 12 and is connected to the transmission mechanism. The top of the valve cover 12 is provided with a groove for installing the transmission mechanism.

[0046] like Figure 1As shown, the transmission mechanism includes a driving nut 14, a driving bearing 15 and a bearing cover 16. The driving bearing 15 can be a ball bearing, which is used to support and limit the rotation direction of the driving nut 14. The functions of the bearing cover 16 mainly include axial positioning, dust prevention and sealing. The lower half of the driving nut 14 is arranged in the groove at the top of the valve cover 12, and is sleeved on the head end of the valve stem 13 to drive the valve stem 13 to move upward or downward. The upper half of the driving nut 14 is fixedly connected to the hand wheel 17, so as to control the opening and closing of the stop valve by the rotation of the hand wheel 17. The driving bearing 15 is arranged in the groove and sleeved on the driving nut 14. The groove is provided with an internal thread, and the contact part of the driving nut 14 and the groove is provided with an external thread, and the external thread of the driving nut 14 is meshed with the internal thread on the groove. When the handle 17 is rotated, the driving nut 14 is driven to rotate, and the driving nut 14 moves up and down in the groove by rotating in different directions, thereby realizing the opening and closing of the stop valve. The bearing cover 16 is arranged on the driving bearing 15 and at the top end of the valve cover 12 to fix the driving bearing 15. The hand wheel 17, the driving nut 14 and the driving bearing 15 cooperate so that the driving nut 14 can move up and down in the groove by rotating to realize the switching from rotational motion to linear motion.

[0047] It can be understood that the valve cover 12 and the valve body 1 can be fixed by bolts, and the connection method of the two components can also be adjusted according to the situation, all of which are within the protection scope of the present invention.

[0048] Another typical embodiment of the present invention provides a sealing method, using the above-mentioned stop valve to connect the pipeline with the inlet and outlet holes 19. Specifically, the upper inlet and outlet 19 is connected to the liquid inlet pipe, and the lower inlet and outlet 19 is connected to the liquid outlet pipe.

[0049] When closing the valve, the hand wheel 17 is turned to drive the driving bearing 15 and the driving nut 14 to rotate, so that the driving nut 14 rises in the groove, drives the valve stem 13 to move toward the head end, and the first valve core 8 moves upward to contact the sealing surface of the first valve seat 9 to achieve the first seal. At the same time, the second valve core 3 moves downward to contact the sealing surface of the second valve seat 2 to achieve the second seal. The whole process achieves the purpose of double sealing, and the sealing effect is doubled.

[0050] When opening the valve, the hand wheel 17 is rotated in the opposite direction to drive the driving bearing 15 and the driving nut 14 to rotate, so that the driving nut 14 drops in the groove, and the valve stem 13 moves toward the end. The hand wheel 17 is rotated continuously, and the first valve core 8 moves downward to leave the first valve seat 9, and the sealing surface of the first valve core 8 is separated from the sealing surface of the first valve seat 9. At the same time, the second valve core 3 moves upward to leave the second valve seat 2, and the sealing surface of the second valve 3 is separated from the sealing surface of the second valve seat 2, and the two inlet and outlet holes 19 are connected. After the hand wheel 17 is continuously rotated to the required position, the valve is fully opened.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A stop valve with a double valve core and valve seat, characterized in that: The valve body comprises a valve body, a hand wheel, a transmission mechanism, a valve stem and a sealing mechanism, wherein a mounting hole is arranged in the valve body, and two inlet and outlet holes respectively connected to the mounting hole are arranged in the valve body, and the sealing mechanism is arranged in the mounting hole, and comprises a first valve seat, a first valve core, a valve core transmission assembly, a second valve core and a second valve seat which are connected in sequence, the hand wheel is connected to the head end of the valve stem through the transmission mechanism, and the end of the valve stem is connected to the first valve core, when the valve stem pushes the first valve core to move in the direction of the second valve core, the second valve core moves in the direction of the first valve core under the drive of the valve core transmission assembly, and the two valve cores leave the valve seat respectively to connect the two inlet and outlet holes, the valve stem drives the first valve core to move in the direction away from the second valve core, and the second valve core moves in the direction away from the first valve core under the drive of the valve core transmission assembly, and the two valve cores respectively seal and contact the sealing surface of the valve seat to isolate the two inlet and outlet holes.

2. The stop valve with double valve core and valve seat as claimed in claim 1, characterized in that: The mounting hole extends along the axis of the stop valve, and the openings of the two inlet and outlet holes connected to the side walls of the mounting hole are staggered in the axial direction.

3. The stop valve with double valve core and valve seat as claimed in claim 1, characterized in that: The valve core transmission assembly includes a first connecting rod, a second connecting rod, a transmission wheel and a transmission shaft. The transmission wheel is sleeved on the transmission shaft and rotates around the transmission shaft. The first connecting rod and the second connecting rod are arranged on both sides of the transmission wheel. The rotation of the transmission wheel drives the first connecting rod and the second connecting rod to move in opposite directions. The transmission shaft is connected to the valve body.

4. The stop valve with double valve core and valve seat as claimed in claim 3, characterized in that: The first connecting rod and the transmission wheel, as well as the second connecting rod and the transmission wheel are all driven by gear racks.

5. The stop valve with double valve core and valve seat as claimed in claim 1, characterized in that: The valve body is also provided with a sealing device which is sleeved on the outside of the valve stem and arranged in a mounting hole above the sealing mechanism.

6. The stop valve with double valve core and valve seat as claimed in claim 5, characterized in that: The sealing device is a valve stem sealing ring.

7. The stop valve with double valve core and valve seat as claimed in claim 1, characterized in that: The end of the valve stem is provided with a valve stem thrust mechanism, the end of the valve stem thrust mechanism is fixedly connected to the first valve core, the valve stem thrust mechanism is composed of three cylinders with different diameters fixed in the order of decreasing diameters, the centers of the bottom circles of the three cylinders are on the same straight line, the cylinder with the largest diameter is connected to the end of the valve stem, and its diameter is the diameter of the mounting hole, the diameters of the remaining two cylinders are smaller than the diameters of the through hole in the first valve seat, and the cylinder with the smallest diameter is connected to the first valve core; Preferably, the cylinder with the smallest diameter is embedded in the first valve core.

8. The stop valve with double valve core and valve seat as claimed in claim 1, characterized in that: The stop valve further comprises a valve cover, which is arranged above the valve body and fixedly connected to the valve body, the valve stem passes through the valve cover and is connected to the transmission mechanism, and a groove for installing the transmission mechanism is provided on the top of the valve cover; The transmission mechanism includes a driving nut, a driving bearing and a bearing pressure cover. A part of the driving nut is arranged in a groove on the top of the valve cover and is sleeved on the head end of the valve stem, and a part is fixedly connected to the handwheel. The driving bearing is arranged in the groove and sleeved on the driving nut. The bearing pressure cover is arranged on the driving nut and is arranged on the top of the valve cover to fix the driving bearing. The handwheel, the driving nut and the driving bearing cooperate so that the driving nut can move up and down in the groove by rotation.

9. The stop valve with double valve core and valve seat as claimed in claim 8, characterized in that: The valve cover is fixed to the valve body by bolts.

10. A sealing method, characterized in that: Use the stop valve described in any one of claims 1 to 9, connect the pipeline to the inlet and outlet holes, turn the hand wheel to drive the valve stem to move upward, the first valve core seals the first valve seat upward, and the second valve core seals the second valve seat downward, the two inlet and outlet holes are isolated, and sealing is achieved; turn the hand wheel to drive the valve stem to move downward, the first valve core moves downward and leaves the first valve seat, the second valve core moves upward and leaves the valve seat, the two inlet and outlet holes are connected, and communication is achieved.

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