Fixed ball valve and method for controlling flow through pressure difference before fluid flows in and after fluid flows out

Abstract

The invention discloses a fixed ball valve and method for controlling the flow through the pressure difference of fluid before flowing in and after flowing out, and belongs to the technical field of fixed ball valves. The wide ends of a first valve seat frame and a second valve seat frame are inserted into an opening in the innermost side of the inlet end and the outlet end of a valve body respectively, and the outer sides of valve seats make contact with the wide ends of the first valve seat frame and the second valve seat frame; the inner side of the valve seat is in contact with a valve element of the valve ball, and the valve seat is made of polytetrafluoroethylene. The narrow end of the first valve seat frame is sleeved with the inner side end of the inlet connector, the narrow end of the second valve seat frame is sleeved with the inner side end of the outlet connector, the narrow end of the first valve seat frame is sleeved with a first belleville spring set, one end of the first belleville spring set makes contact with the wide end of the first valve seat frame, and the other end of the first belleville spring set makes contact with the inner side end of the inlet connector. The narrow end of the second valve seat frame is sleeved with a second belleville spring set, one end of the second belleville spring set makes contact with the wide end of the second valve seat frame, the other end of the second belleville spring set makes contact with the inner side end of the outlet connector, and the fluid flow and the pressure difference before inflow and after outflow can be in a linear relation.

Description

Technical Field

[0001] The present invention belongs to the technical field of fixed ball valves, and in particular relates to a fixed ball valve and a method for controlling flow rate by pressure difference before fluid flows in and after fluid flows out. Background Art

[0002] A ball valve is a widely used pipeline device for controlling the flow, pressure and temperature of fluid media. The working principle of a ball valve is that the ball is driven by the valve stem and rotates around an axis perpendicular to the channel. The ball rotates with the valve stem to achieve the purpose of opening and closing the channel. When the ball valve rotates 90 degrees, the inlet and outlet should all present spherical surfaces, thereby closing the valve and cutting off the flow of the medium; when the ball valve rotates 90 degrees, the inlet and outlet should all present ball openings, thereby opening the flow, and there is basically no fluid resistance. Ball valves play an important role in various fields due to their low fluid resistance, good sealing, easy operation, and convenient maintenance.

[0003] The existing ball valve is mainly composed of a valve body, a valve seat, a valve ball, a valve stem, a seal and an operating part. It is structurally divided into a floating ball valve, a fixed ball valve, an elastic ball valve and a V-type ball valve. The valve ball of the floating ball valve has no supporting shaft. The ball is supported by the valve seats at both ends of the valve inlet and outlet. The valve stem and the ball are movably connected. Under the pressure of the medium, the ball of this ball valve can produce a certain displacement and press tightly on the sealing surface of the outlet end to ensure the sealing of the outlet end. It is widely used in medium and low pressure pipelines. The ball of the elastic ball valve is elastic. The ball and the valve seat sealing ring are made of metal materials, and the sealing pressure ratio is very large. This valve needs to rely on the pressure of the medium itself and the external force to achieve sealing, and is suitable for high temperature and high pressure media. The ball of the V-type ball valve is designed with a V-shaped opening, which can be used for flow regulation.

[0004] The valve ball of a fixed ball valve is fixed and does not move when under pressure. The ball of a fixed ball valve is connected to the upper and lower valve stems or made into an integral shaft-type ball, and the ball can rotate freely along an axis perpendicular to the valve channel. During the use of the fixed ball valve, when the opening degree of the valve increases, the flow area of ​​the fluid also increases, allowing more fluid to pass through the valve. However, the increase in flow also means that the flow rate of the fluid increases when passing through the valve, resulting in increased friction and turbulence between the fluid and the inside of the valve, that is, the resistance of the fluid passing through the valve increases, which in turn produces a greater pressure drop. After the current fixed ball valve passes a certain flow of fluid, when the flow reaches a certain level, the pressure drop value still changes nonlinearly with the flow of the fluid. It is impossible to control the flow by adjusting the pressure difference before and after the valve, which is not conducive to maintaining the overall stability of the fluid system. Summary of the invention

[0005] In response to the problems existing in the prior art, the present invention provides a fixed ball valve and method for controlling flow by the pressure difference before the fluid flows in and after the fluid flows out, which solves the problem that the current fixed ball valve cannot control the flow by adjusting the pressure difference before and after the valve, which is not conducive to maintaining the overall stability of the fluid system.

[0006] The present invention is achieved through the following technical solutions: A fixed ball valve that controls flow by pressure difference before and after fluid flows in and out, comprising a valve body, a valve seat, an inlet joint, an outlet joint and a valve seat frame, wherein the valve seat frame comprises a first valve seat frame and a second valve seat frame, both of which are T-shaped and hollow structures: The two ends of the valve body in the length direction are respectively an inlet end and an outlet end, both of which are stepped structures and the openings are continuously reduced from the outside to the inside, the wide end of the first valve seat frame is movably plugged into the innermost opening of the inlet end, and the wide end of the second valve seat frame is movably plugged into the innermost opening of the outlet end, and a plug-in matching valve ball and valve stem are installed from bottom to top in the channel center in the height direction of the valve body, the outer side of the valve seat contacts with the wide end of the first valve seat frame and the wide end of the second valve seat frame, and the inner side of the valve seat contacts with the valve core of the valve ball, and the material of the valve seat is polytetrafluoroethylene; The inlet joint is fixedly inserted at the inlet end, the inner side end of the inlet joint is pressed against the step closest to the first valve seat frame at the inlet end and is fixedly sleeved on the narrow end of the first valve seat frame, and the outlet joint is fixedly inserted at the outlet end, the inner side end of the outlet joint is pressed against the step closest to the second valve seat frame at the outlet end and is fixedly sleeved on the narrow end of the second valve seat frame; A first disc spring group is sleeved on the narrow end of the first valve seat frame, one end of the first disc spring group contacts the wide end of the first valve seat frame, and the other end contacts the inner end of the inlet joint. A second disc spring group is sleeved on the narrow end of the second valve seat frame, one end of the second disc spring group contacts the wide end of the second valve seat frame, and the other end contacts the inner end of the outlet joint.

[0007] A further improvement of the present invention is: The channels of the inlet joint and the outlet joint are both cylindrical, and the central axes of the channel of the inlet joint, the channel of the outlet joint, the channel of the first valve seat frame, the channel of the second valve seat frame and the valve core channel of the valve ball coincide with each other. When in the open state, the valve core channel of the valve ball coincides with the valve seat and the channel of the first valve seat frame.

[0008] It also includes a handle, a brass bushing is fitted inside the groove in the handle, the upper end of the valve stem is fixedly inserted in the brass bushing, and a transverse installation groove connected to the outside is radially arranged at a position on the handle corresponding to the brass bushing, a fixing screw is installed in the transverse installation groove, and the handle and the upper end of the valve stem are fixed by the fixing screw.

[0009] The valve stem is a T-shaped structure with a circular cross section. The channel in the height direction of the valve body is cylindrical. The inner diameter of the upper opening is smaller than the inner diameter of the channel. The diameter of the narrow end of the valve stem is the same as the inner diameter of the channel. The narrow end of the valve stem is inserted into the opening above the valve body from bottom to top, the lower surface of the wide end of the valve stem is provided with a rectangular groove, the top of the valve ball is provided with a rectangular boss that is inserted into the rectangular groove, the rectangular boss is inserted into the rectangular groove, and the handle and the end of the narrow end of the valve stem are fixed by fixing screws.

[0010] The valve ball includes a spherical valve core and an upper ear shaft and a lower ear shaft which are symmetrically distributed on the upper and lower sides of the valve core and have the same shape and size. The upper ear shaft includes an integrated first cylindrical section and a second cylindrical section from top to bottom. The diameter of the valve core is larger than the diameter of the second cylindrical section and smaller than the diameter of the first cylindrical section. A rectangular boss is extended upward from the center of the length direction of the upper surface of the first cylindrical section. The lower ear shaft includes an integrated third cylindrical section and a fourth cylindrical section from bottom to top. The lower surface of the third cylindrical section is close to the bottom of the valve body.

[0011] Two annular grooves are arranged along the circumference of the valve stem at a position near the wide end of the narrow end of the valve stem, each annular groove is filled with a valve stem O-ring, each valve stem O-ring is compressed and fits with the inner wall of the upper opening of the valve body, and a support ring is arranged between the upper end surface of the wide end of the valve stem and the lower end surface of the upper opening of the valve body; The first cylindrical segment is provided with a first annular groove circumferentially along the center position of its own height, the third cylindrical segment is provided with a second annular groove circumferentially along the center position of its own height, the first annular groove is provided with an ear shaft support ring and an ear shaft O-ring from top to bottom, and the second annular groove is provided with an ear shaft support ring and an ear shaft O-ring from bottom to top.

[0012] The wide ends of the first valve seat frame and the second valve seat frame extend deep into the channel in the height direction of the valve body and leave gaps with the outer walls of the second cylindrical section and the fourth cylindrical section respectively. The inner ends of the inlet joint and the outlet joint are both cylindrical, and the ends of the cylinders are each provided with an annular notch, and the annular notch is filled with a joint sealing ring.

[0013] A valve seat frame guide, a first valve seat frame support ring, a second valve seat frame support ring and a valve seat frame O-ring are arranged at a position corresponding to the narrow end of the first valve seat frame and the inner side end of the inlet joint, one end of the valve seat frame guide is in contact with the first disc spring group, and the other end is in contact with the first valve seat frame support ring, one end of the valve seat frame O-ring is in contact with the first valve seat frame support ring, and the other end is in contact with the second valve seat frame support ring, and the inner side end of the inlet joint is fixedly sleeved on the narrow end of the first valve seat frame through the valve seat frame guide, the first valve seat frame support ring, the valve seat frame O-ring and the second valve seat frame support ring; A valve seat frame guide, a first valve seat frame support ring, a second valve seat frame support ring and a valve seat frame O-ring are provided at a position corresponding to the narrow end of the second valve seat frame and the inner side end of the outlet joint. One end of the valve seat frame guide is in contact with the second disc spring group, and the other end is in contact with the first valve seat frame support ring. One end of the valve seat frame O-ring is in contact with the first valve seat frame support ring, and the other end is in contact with the second valve seat frame support ring. The inner side end of the outlet joint is fixedly sleeved on the narrow end of the second valve seat frame through the valve seat frame guide, the first valve seat frame support ring, the valve seat frame O-ring and the second valve seat frame support ring.

[0014] The first disc spring group and the second disc spring group are both formed by 5 to 8 disc springs stacked in the same direction.

[0015] The present invention provides a method for controlling flow rate by using the pressure difference before the fluid flows in and after the fluid flows out, based on any one of the above-mentioned fixed ball valves for controlling flow rate by using the pressure difference before the fluid flows in and after the fluid flows out, comprising the following steps: S1, when the fixed ball valve is fully opened, the fluid flows into the valve core of the valve ball from the inlet joint, the first valve seat frame and one side of the valve seat in sequence, and then flows out from the other side of the valve seat, the second valve seat frame and the outlet joint in sequence; S2, when the fluid flow reaches a certain amount, the fluid completely occupies the passages of the inlet joint, the first valve seat frame, the valve seat, the valve core of the valve ball, the second valve seat frame and the outlet joint; S3, the fluid flow rate continues to increase, pushing the first valve seat frame to move toward the valve core of the valve ball, the butterfly spring in the first disc spring group expands, and the valve core of the valve ball pushes the second valve seat frame to move toward the outlet joint through the valve seat, and the disc spring in the second disc spring group is compressed. The compression and expansion of the disc spring ensure that the valve seat and the valve core of the valve ball are always tightly fitted, reducing the pressure loss before and after the fluid flows in. The polytetrafluoroethylene material of the valve seat reduces the friction loss between the valve seat and the valve core of the valve ball, so that the fluid flow rate is linearly related to the pressure difference before and after the fluid flows in. Then, the pressure difference before and after the fluid flows out is adjusted to complete the control of the fluid flow rate.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention controls the flow of a fixed ball valve by the pressure difference before the fluid flows in and after the fluid flows out. The fluid flows into the valve core of the valve ball from the inlet joint, the first valve seat frame and one side of the valve seat in sequence, and then flows out from the other side of the valve seat, the second valve seat frame and the outlet joint in sequence. At this time, the fluid flow is small and cannot completely occupy the passage of the valve ball. The fluid flow and its pressure drop are in a nonlinear relationship. When the fluid completely occupies the passages of the inlet joint, the first valve seat frame, the valve seat, the valve core of the valve ball, the second valve seat frame and the outlet joint, the flow continues to increase, which will push the first valve seat frame to move toward the valve core of the valve ball. Since the disc spring has good buffering performance and can absorb and disperse impact force, the first disc spring assembly The butterfly spring in the valve will expand, and the valve core of the valve ball will push the second valve seat frame to move toward the outlet joint through the valve seat. The disc spring in the second disc spring group will be compressed. In this way, the compression and expansion of the disc spring can ensure that the valve seat and the valve core of the valve ball are always closely fitted, reducing the pressure loss before and after the fluid flows in. The polytetrafluoroethylene material of the valve seat is resistant to high and low temperatures, corrosion, and high lubricity. It can reduce the friction loss between the valve seat and the valve core of the valve ball, thereby reducing the pressure drop, making the fluid flow rate and the pressure difference before and after the fluid flows in a linear relationship, and can also protect the valve ball from damage. After that, the pressure difference before and after the fluid flows in can be adjusted to complete the control of the fluid flow. The stable flow-pressure drop relationship can ensure the stable operation and performance of the system in applications that require precise control of fluid flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the fixed ball valve of the present invention.

[0018] Figure 2 It is a cross-sectional view of the fixed ball valve of the present invention.

[0019] Figure 3a for Figure 2 Front view of the valve stem in.

[0020] Figure 3b for Figure 2 Cross-sectional view of the valve stem in .

[0021] Figure 4a for Figure 2 Front view of the valve ball in.

[0022] Figure 4b for Figure 2 Cross-sectional view of the valve ball in .

[0023] Figure 5 The relationship diagram between the pressure drop and flow rate of compressed air and water passing through the valve at 20°C.

[0024] In the figure: 1-handle; 2-fixing screw; 3-valve stem; 31-rectangular groove, 4-valve stem O-ring; 5-stop pin; 6-valve body; 61-inlet end; 62-outlet end; 7-panel nut; 8-support ring; 9-valve ball; 91-rectangular boss; 92-upper ear shaft; 93-lower ear shaft; 10-ear shaft support ring; 11-ear shaft O-ring; 12-inlet connector; 131-first valve seat frame support ring; 132-second valve seat frame support ring; 14-valve seat frame O-ring; 15-valve seat frame guide; 16-connector sealing ring; 171-first disc spring group; 172-second disc spring group; 181-first valve seat frame; 182-second valve seat frame; 19-valve seat; 20-outlet connector. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0026] The present invention can control the flow rate by the pressure difference (i.e., pressure drop) before the fluid flows in and after the fluid flows out. of The overall structure of the fixed ball valve is as follows Figure 1 As shown, it mainly includes a handle 1, a valve stem 3, a valve body 6, an inlet connector 12 and an outlet connector 20. The valve body 6 is a cross-shaped structure, and the cross-sections in the length direction and the height direction are both circular rings. The two ends in the length direction are respectively an inlet end 61 and an outlet end 62 with the same structure and symmetric along the length direction of the valve body 6. The cross-sectional view is shown in FIG. Figure 2 As shown, it can be seen that a valve seat 19 and a valve seat frame are also included. The valve seat frame specifically includes a first valve seat frame 181 and a second valve seat frame 182. The structures and sizes of the two are the same, and they are T-shaped hollow structures.

[0027] The valve ball 9 and the valve stem 3 are installed from bottom to top in the channel center in the height direction of the valve body 6. Figure 4a and Figure 4bAs shown, the valve ball 9 adopts a trunnion structure, including a spherical valve core and an upper trunnion 92 and a lower trunnion 93 symmetrically distributed on the upper and lower sides of the valve core. The upper trunnion 92 and the lower trunnion 93 have the same shape and size. The upper trunnion 92 includes an integral first cylindrical section and a second cylindrical section from top to bottom. The diameter of the valve core is larger than the diameter of the second cylindrical section and smaller than the diameter of the first cylindrical section. A rectangular boss 91 is extended upward from the center of the length direction of the upper surface of the first cylindrical section. Correspondingly, the lower trunnion 93 includes an integral third cylindrical section and a fourth cylindrical section from bottom to top, and the lower surface of the third cylindrical section is close to the bottom of the valve body 6. The inlet end 61 and the outlet end 62 are specifically a stepped structure, and the opening is continuously reduced from the outside to the inside. The wide end of the first valve seat frame 181 is inserted into the innermost opening of the inlet end 61 and the wide end of the first valve seat frame 181 is arranged in contact with the inner wall of the opening. Similarly, the wide end of the second valve seat frame 182 is inserted into the innermost opening of the outlet end 62, and the wide end of the second valve seat frame 182 is arranged in close contact with the inner wall of the opening. The valve seat 19 is an arc-shaped body with two hollow structures, the outer sides of which are respectively inserted into the gaps of the wide ends of the first valve seat frame 181 and the second valve seat frame 182 and contact each other, and the inner sides are in contact with the spherical valve core, so that the two sides of the spherical valve core can be tightened by the valve seat 19 to prevent the valve ball from rushing out. The material of the valve seat 19 is polytetrafluoroethylene, which has excellent corrosion resistance and sealing properties. At the same time, the friction coefficient is extremely low, which helps to reduce the friction loss between the valve seat 19 and the valve ball 9. The inlet joint 12 is fixedly inserted in the inlet end 61, specifically, its inner end is pressed against the step closest to the first valve seat frame 181 in the inlet end 61, and the inner end of the inlet joint 12 is fixedly sleeved on the narrow end of the first valve seat frame 181. Similarly, the outlet joint 20 is fixedly inserted in the outlet end 62, and its inner end is pressed against the step closest to the second valve seat frame 182 in the outlet end 62, and the inner end of the outlet joint 20 is fixedly sleeved on the narrow end of the second valve seat frame 182. A first disc spring group 171 is sleeved on the narrow end of the first valve seat frame 181, one end of which contacts the wide end of the first valve seat frame 181, and the other end contacts the inner end of the inlet joint 12. A second disc spring group 172 is sleeved on the narrow end of the second valve seat frame 182, one end of which contacts the wide end of the second valve seat frame 182, and the other end contacts the inner end of the outlet joint 20. The disc spring group plays a pressure-bearing role, ensuring that the ball valve has complete leakage-proof performance in both low-pressure and high-pressure systems, while reducing the wear of the valve seat 19 caused by operating torque and pressure mutations.

[0028] Generally, the channels of the inlet joint 12 and the outlet joint 20 are both cylindrical, and the central axes of the channels of the inlet joint 12, the channels of the first valve seat frame 181, the valve core channels of the valve ball 9, the channels of the second valve seat frame 182 and the channels of the outlet joint 20 coincide with each other. When in the open state, the valve core channels of the valve ball 9 coincide with the channels of the valve seat 19 and the first valve seat frame 181. The surface and channels of the valve ball 9 are coated with a zirconium oxide film to improve the wear resistance, corrosion resistance, oxidation resistance and sealing performance, thereby improving the performance and service life of the ball valve.

[0029] The present invention provides a special-shaped groove on the lower surface of the handle 1. The main structure of the special-shaped groove is cylindrical. The cylinder is provided with a semicircular ring extending radially from the outside to the inside. The thickness of the semicircular ring is 1 / 4 of the depth of the entire cylinder. A brass bushing is fitted in the cylindrical section inside the semicircular ring. The upper end of the valve stem 3 is fixedly inserted in the brass bushing. A transverse installation groove communicating with the outside is provided radially at a position corresponding to the brass bushing on the handle 1. A fixing screw 2 is installed in the transverse installation groove. The handle 1 and the upper end of the valve stem 3 are fixed by the fixing screw 2. The specific structure of the valve stem 3 is as follows: Figure 3a and Figure 3b As shown, it is T-shaped and has a circular cross section. The channel in the height direction of the valve body 6 is cylindrical, and the inner diameter of the upper opening is smaller than the inner diameter of the channel. The narrow end diameter of the valve stem 3 is the same as the inner diameter of the channel. The narrow end of the valve stem 3 is inserted from bottom to top in the opening above the valve body 6, which can prevent the valve stem 3 from rushing out of the valve body 6, thereby improving safety. The lower surface of the wide end of the valve stem 3 is provided with a rectangular groove 31 that can be plugged with the rectangular boss 91. The rectangular boss 91 is inserted into the rectangular groove 31. After the valve stem 3 and the valve ball 9 are locked in this way, the valve stem 3 is rotated, thereby driving the valve ball 9 to rotate, controlling the opening and closing of the valve, and the operating torque is small. Therefore, the handle 1 and the end of the narrow end of the valve stem 3 are fixed by fixing screws 2. There is a gap between the handle 1 and the upper surface of the valve body 6. Two stop pins 5 are fixedly inserted on the upper surface of the valve body 6 from top to bottom. The upper ends of the two stop pins 5 are higher than the upper surface of the valve body 6, and the central axes of the two stop pins 5 are at the same distance from the center of the upper surface of the valve body 6 and form an arc of π / 4. The parts of the two stop pins 5 that leak out of the upper surface of the valve body 6 are located in the semicircular ring of the special-shaped groove. In this way, when the handle 1 drives the valve ball 9 to rotate through the valve stem 3, it can ensure that the spherical valve core can only rotate 45 degrees, and the fixed ball valve can be opened and closed normally.

[0030] In addition, the present invention installs a panel nut 7 on the outer wall of the valve body 6 in the height direction, so as to facilitate the installation of the mechanical panel when needed.

[0031] In order to install the valve stem 3 and the valve ball 9 stably and tightly and enhance the safety of the fixed ball valve, the present invention sets two annular grooves along the circumference of the valve stem 3 at the position of the narrow end of the valve stem 3 near the wide end, and further fills the valve stem O-ring 4 in each annular groove. After compression, the valve stem O-ring 4 fits with the inner wall of the upper opening of the valve body 6. In addition, a support ring 8 is set between the upper end surface of the wide end of the valve stem 3 and the lower end surface of the upper opening of the valve body 6. For the valve ball 9, a first annular groove is set circumferentially at the center position of the first cylindrical section along its own height, and a second annular groove is set circumferentially at the center position of the third cylindrical section along its own height. A trunnion support ring 10 and a trunnion O-ring 11 are set from top to bottom in the first annular groove, and a trunnion support ring 10 and a trunnion O-ring 11 are set from bottom to top in the second annular groove. The trunnion support ring 10 and the trunnion O-ring 11 play a supporting and sealing role respectively.

[0032] Specifically, the wide end of the first valve seat frame 181 and the wide end of the second valve seat frame 182 penetrate into the channel in the height direction of the valve body 6, and both further leave gaps with the outer walls of the second cylindrical section and the fourth cylindrical section respectively. The inner ends of the inlet joint 12 and the outlet joint 20 are both cylindrical, and an annular notch is provided at the end of the cylinder. The annular notch is filled with a joint sealing ring 16, which can ensure the sealing of the inlet joint 12 and the outlet joint 20 inside the valve body 6.

[0033] The first valve seat frame support ring 131, the second valve seat frame support ring 132, the valve seat frame O-ring 14 and the valve seat frame guide 15 are provided at the position corresponding to the narrow end of the first valve seat frame 181 and the inner side end of the inlet joint 12. One end of the valve seat frame guide 15 is in contact with the first disc spring group 171, and the other end of the valve seat frame guide 15 is in contact with the first valve seat frame support ring 131. One end of the valve seat frame O-ring 14 is in contact with the first valve seat frame support ring 131, and the other end of the valve seat frame O-ring 14 is in contact with the second valve seat frame support ring 132. Therefore, the inner side end of the inlet joint 12 is fixedly sleeved on the narrow end of the first valve seat frame 181 through the first valve seat frame support ring 131, the second valve seat frame support ring 132, the valve seat frame O-ring 14 and the valve seat frame guide 15. Similarly, the first valve seat frame support ring 131, the second valve seat frame support ring 132, the valve seat frame O-ring 14 and the valve seat frame guide 15 are provided at the position corresponding to the narrow end of the second valve seat frame 182 and the inner side end of the outlet joint 20. One end of the valve seat frame guide 15 contacts the second disc spring group 172, and the other end of the valve seat frame guide 15 contacts the first valve seat frame support ring 131. One end of the valve seat frame O-ring 14 contacts the first valve seat frame support ring 131, and the other end of the valve seat frame O-ring 14 contacts the second valve seat frame support ring 132. Therefore, the inner side end of the outlet joint 20 is fixedly sleeved on the narrow end of the second valve seat frame 182 through the first valve seat frame support ring 131, the second valve seat frame support ring 132, the valve seat frame O-ring 14 and the valve seat frame guide 15. The valve seat frame guide 15 can be guided inside the joint. Specifically, the first disc spring group 171 and the second disc spring group 172 are both composed of 5 to 8 disc springs stacked in the same direction. Figure 2 Six disc springs are shown in FIG. The O-ring of the present invention is made of fluororubber, which is a polymer elastic material with excellent high temperature resistance, chemical resistance and oil resistance, and can achieve good sealing performance.

[0034] When the fluid passes through the fixed ball valve, due to the valve's obstruction to the fluid, a certain pressure loss, i.e., pressure drop, will occur. According to Bernoulli's theorem, when the fluid passes through the valve, if the speed increases, the pressure will decrease. When the valve opening remains unchanged, the greater the flow rate of the fluid, the greater the speed when it passes through the valve, resulting in a greater pressure drop. When the flow rate increases, the speed of the fluid passing through the valve will also increase, which will lead to greater energy loss and pressure drop. When the valve opening remains unchanged, that is, the passage area of ​​the valve remains unchanged, the resistance characteristics of the fluid passing through the valve are also relatively stable. Therefore, when the valve opening and other conditions remain unchanged, the increase in flow rate is usually accompanied by an increase in pressure drop. In general, the flow rate and pressure drop are sometimes not strictly proportional, but an approximate or restricted inverse proportional trend.

[0035] The present invention provides a method for controlling flow rate by using the pressure difference before the fluid flows in and after the fluid flows out, which can be based on the fixed ball valve of the above structure and can realize the positive proportional relationship between flow rate and pressure drop, and specifically comprises the following steps: Step 1, fully open the fixed ball valve, and the fluid flows into the valve core of the valve ball 9 from the inlet connector 12, the first valve seat frame 181 and one side of the valve seat 19 in sequence, and then flows out from the other side of the valve seat 19, the second valve seat frame 182 and the outlet connector 20 in sequence; At this time, the fluid flow rate is small and cannot completely occupy the passage of the valve ball. The fluid flow rate and its pressure drop have a nonlinear relationship; Step 2, when the fluid flow reaches a certain amount, the fluid completely occupies the passages of the inlet connector 12, the first valve seat frame 181, the valve seat 19, the valve core of the valve ball 9, the second valve seat frame 182 and the outlet connector 20; Step 3, the fluid flow rate continues to increase, which will push the first valve seat frame 181 to move toward the valve core of the valve ball 9. At this time, the butterfly spring in the first disc spring group 171 is relaxed, and the valve core of the valve ball 9 pushes the second valve seat frame 182 to move toward the outlet joint 20 through the valve seat 19. The disc spring in the second disc spring group 172 will be compressed. In this way, the compression and relaxation of the disc spring can ensure that the valve seat 19 and the valve core of the valve ball 9 are always tightly fitted, reducing the pressure loss before and after the fluid flows in. The polytetrafluoroethylene material of the valve seat 19 reduces the friction loss between the valve seat 19 and the valve core of the valve ball 9, so that the fluid flow rate is linearly related to the pressure difference before and after the fluid flows in. After that, the pressure difference before and after the fluid flows out can be adjusted to complete the control of the fluid flow rate.

[0036] according to Figure 5 When the ball valve is fully opened, when the fluid is compressed air, after the pressure drop is 1MPa, as the pressure drop of air increases, the air flow rate basically increases linearly. When the fluid is water, after the pressure drop is 5MPa, as the pressure drop of water increases, the water flow rate basically increases linearly.

[0037] The flow rate of a fluid is linearly related to its pressure drop, which means that when a fluid passes through a valve, there is a direct, proportional relationship between its flow rate (volume of fluid passing through the valve per unit time) and its pressure drop. Since the valve opening remains unchanged, the flow channel of the fluid remains stable, so the resistance encountered by the fluid when passing through the valve is also relatively constant.

[0038] Since the flow rate of a fluid is linearly related to its pressure drop, the flow rate can be controlled by adjusting the pressure difference before and after the valve. In a fluid system, a stable flow-pressure drop relationship helps maintain the overall stability of the system. For example, in applications that require precise control of fluid flow (such as chemical processes, water supply systems, etc.), a stable flow-pressure drop relationship can ensure stable operation and performance of the system.

Claims

1. A fixed ball valve that controls the flow rate by the pressure difference between the fluid before it flows in and after it flows out, characterized in that: It comprises a valve body (6), a valve seat (19), an inlet joint (12), an outlet joint (20) and a valve seat frame, wherein the valve seat frame comprises a first valve seat frame (181) and a second valve seat frame (182), both of which are T-shaped and hollow structures; The two ends of the valve body (6) in the length direction are respectively an inlet end (61) and an outlet end (62); the inlet end (61) and the outlet end (62) are both stepped structures and the openings are gradually reduced from the outside to the inside; the wide end of the first valve seat frame (181) is movably inserted into the innermost opening of the inlet end (61); the wide end of the second valve seat frame (182) is movably inserted into the innermost opening of the outlet end (62); the outer side of the valve seat (19) contacts the wide end of the first valve seat frame (181) and the wide end of the second valve seat frame (182); the inner side of the valve seat (19) contacts the valve core of the valve ball (9); and the material of the valve seat (19) is polytetrafluoroethylene; The inner end of the inlet joint (12) is fixedly sleeved on the narrow end of the first valve seat frame (181), and the inner end of the outlet joint (20) is fixedly sleeved on the narrow end of the second valve seat frame (182). A first disc spring group (171) is sleeved on the narrow end of the first valve seat frame (181), one end of the first disc spring group (171) contacts the wide end of the first valve seat frame (181), and the other end contacts the inner end of the inlet joint (12). A second disc spring group (172) is sleeved on the narrow end of the second valve seat frame (182), one end of the second disc spring group (172) contacts the wide end of the second valve seat frame (182), and the other end contacts the inner end of the outlet joint (20).

2. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 1, characterized in that: The inlet joint (12) is fixedly plugged into the inlet end (61), and the inner end of the inlet joint (12) is pressed tightly against the step of the inlet end (61) that is closest to the first valve seat frame (181); the outlet joint (20) is fixedly plugged into the outlet end (62), and the inner end of the outlet joint (20) is pressed tightly against the step of the outlet end (62) that is closest to the second valve seat frame (182); The channels of the inlet joint (12) and the outlet joint (20) are both cylindrical; the central axes of the channel of the inlet joint (12), the channel of the outlet joint (20), the channel of the first valve seat frame (181), the channel of the second valve seat frame (182) and the valve core channel of the valve ball (9) coincide with each other; in the open state, the valve core channel of the valve ball (9) coincides with the channel of the valve seat (19) and the first valve seat frame (181).

3. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 1, characterized in that: It also includes a handle (1), a valve ball (9) and a valve stem (3) which are plug-fitted and mounted from bottom to top at the center of the channel in the height direction of the valve body (6), a brass bushing being fitted inside the groove in the handle (1), the upper end of the valve stem (3) being fixedly plugged into the brass bushing, a transverse mounting groove which is in radial communication with the outside world being arranged at a position on the handle (1) corresponding to the brass bushing, a fixing screw (2) being mounted in the transverse mounting groove, and the handle (1) and the upper end of the valve stem (3) being fixed by the fixing screw (2).

4. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 3, characterized in that: The valve stem (3) is of a T-shaped structure and has a circular cross section. The passage in the height direction of the valve body (6) is cylindrical, the inner diameter of the upper opening is smaller than the inner diameter of the passage, and the diameter of the narrow end of the valve stem (3) is the same as the inner diameter of the passage. The narrow end of the valve stem (3) is inserted into the opening above the valve body (6) from bottom to top, the lower surface of the wide end of the valve stem (3) is provided with a rectangular groove (31), the top of the valve ball (9) is provided with a rectangular boss (91) that is inserted into the rectangular groove (31), and the rectangular boss (91) is inserted into the rectangular groove (31), and the handle (1) and the end of the narrow end of the valve stem (3) are fixed by a fixing screw (2).

5. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 4, characterized in that: The valve ball (9) comprises a spherical valve core and an upper ear shaft (92) and a lower ear shaft (93) which are symmetrically distributed on the upper and lower sides of the valve core and have the same shape and size. The upper ear shaft (92) comprises an integral first cylindrical section and a second cylindrical section from top to bottom. The diameter of the valve core is greater than the diameter of the second cylindrical section and smaller than the diameter of the first cylindrical section. A rectangular boss (91) is provided extending upward from the center of the length direction of the upper surface of the first cylindrical section. The lower ear shaft (93) comprises an integral third cylindrical section and a fourth cylindrical section from bottom to top. The lower surface of the third cylindrical section is close to the bottom of the valve body (6).

6. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 5, characterized in that: Two annular grooves are arranged along the circumference of the valve stem (3) at a position near the wide end of the narrow end of the valve stem (3); each annular groove is filled with a valve stem O-ring (4); each valve stem O-ring (4) is arranged to fit the inner wall of the upper opening of the valve body (6) after being compressed; and a support ring (8) is arranged between the upper end surface of the wide end of the valve stem (3) and the lower end surface of the upper opening of the valve body (6); The first cylindrical segment is provided with a first annular groove along the circumference of the center position of its own height, and the third cylindrical segment is provided with a second annular groove along the circumference of the center position of its own height, wherein a trunnion support ring (10) and a trunnion O-ring (11) are provided in the first annular groove from top to bottom, and a trunnion support ring (10) and a trunnion O-ring (11) are provided in the second annular groove from bottom to top.

7. The fixed ball valve for controlling flow rate by pressure difference between before fluid flows in and after fluid flows out according to claim 5, characterized in that: The wide ends of the first valve seat frame (181) and the second valve seat frame (182) extend deep into the channel in the height direction of the valve body (6) and leave gaps with the outer walls of the second cylindrical section and the fourth cylindrical section respectively. The inner ends of the inlet joint (12) and the outlet joint (20) are both cylindrical, and the ends of the cylinders are each provided with an annular notch, and the annular notch is filled with a joint sealing ring (16).

8. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 1, characterized in that: A valve seat frame guide (15), a first valve seat frame support ring (131), a second valve seat frame support ring (132) and a valve seat frame O-ring (14) are provided at a position corresponding to the narrow end of the first valve seat frame (181) and the inner side end of the inlet joint (12); one end of the valve seat frame guide (15) contacts the first disc spring group (171) and the other end contacts the first valve seat frame support ring (131); one end of the valve seat frame O-ring (14) contacts the first valve seat frame support ring (131) and the other end contacts the second valve seat frame support ring (132); the inner side end of the inlet joint (12) is fixedly sleeved on the narrow end of the first valve seat frame (181) through the valve seat frame guide (15), the first valve seat frame support ring (131), the valve seat frame O-ring (14) and the second valve seat frame support ring (132); A valve seat frame guide (15), a first valve seat frame support ring (131), a second valve seat frame support ring (132) and a valve seat frame O-ring (14) are provided at a position corresponding to the narrow end of the second valve seat frame (182) and the inner side end of the outlet joint (20); one end of the valve seat frame guide (15) contacts the second disc spring group (172), and the other end contacts the first valve seat frame support ring (131); one end of the valve seat frame O-ring (14) contacts the first valve seat frame support ring (131), and the other end contacts the second valve seat frame support ring (132); the inner side end of the outlet joint (20) is fixedly sleeved on the narrow end of the second valve seat frame (182) through the valve seat frame guide (15), the first valve seat frame support ring (131), the valve seat frame O-ring (14) and the second valve seat frame support ring (132).

9. The fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out according to claim 1, characterized in that: The first disc spring group (171) and the second disc spring group (172) are both formed by 5 to 8 disc springs stacked in the same direction.

10. A method for controlling flow rate by pressure difference before fluid flows in and after fluid flows out, based on the fixed ball valve for controlling flow rate by pressure difference before fluid flows in and after fluid flows out as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1, when the fixed ball valve is fully opened, the fluid flows into the valve core of the valve ball (9) from the inlet joint (12), the first valve seat frame (181) and one side of the valve seat (19) in sequence, and then flows out from the other side of the valve seat (19), the second valve seat frame (182) and the outlet joint (20) in sequence; S2, when the fluid flow reaches a certain amount, the fluid completely occupies the passages of the inlet connector (12), the first valve seat frame (181), the valve seat (19), the valve core of the valve ball (9), the second valve seat frame (182) and the outlet connector (20); At step S3, the fluid flow rate continues to increase, pushing the first valve seat frame (181) to move toward the valve core of the valve ball (9), the disc spring in the first disc spring group (171) expands, and the valve core of the valve ball (9) pushes the second valve seat frame (182) to move toward the outlet connector (20) through the valve seat (19). The disc spring in the second disc spring group (172) is compressed. The compression and expansion of the disc spring ensure that the valve seat (19) and the valve core of the valve ball (9) are always tightly fitted, thereby reducing the pressure loss before and after the fluid flows in. The polytetrafluoroethylene material of the valve seat (19) reduces the friction loss between the valve seat (19) and the valve core of the valve ball (9), so that the fluid flow rate is linearly related to the pressure difference before and after the fluid flows in. The pressure difference before and after the fluid flows out is then adjusted to complete the control of the fluid flow rate.

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