Control valve with water hammer mitigation function

Abstract

The present invention relates to the technical field of control valves. Disclosed is a control valve with a water hammer mitigation function. The control valve comprises a valve body, an adjustment frame, a hand wheel, a force transmission pipe, a buffer assembly, a valve core assembly, a valve rod and a force transmission assembly. The present invention converts, by means of a compression medium, kinetic energy generated by fluid impact force into mechanical transmission energy for deflecting a first transmission ring and a second transmission ring, ultimately achieving the purpose of deploying buffer plates without an external driving force. By means of the synchronous deployment of a first buffer plate and a second buffer plate, a dual buffer barrier is formed, and water hammer impact energy is effectively dispersed. Stage-wise buffering is performed on a forward-impacting fluid, and secondary energy absorption is performed on a counter-flow fluid, thereby achieving the purpose of two-stage mitigation of water hammer. By means of the design of a variable-volume compression chamber, the compression chamber can automatically adaptively change on the basis of the magnitude of a water hammer impact force, which in turn enables the first buffer plate and the second buffer plate to be adaptively deployed at corresponding angles on the basis of the magnitude of the water hammer impact force.

Description

A control valve with water hammer reduction function Technical Field

[0001] Control valves play a crucial role in various piping systems, enabling precise fluid regulation and rapid shut-off of media flow when necessary, ensuring system safety and stability. By adjusting the valve opening, control valves regulate fluid velocity and flow rate, allowing the system to operate under optimal conditions according to design requirements. Control valves not only provide regulation and protection during routine operation but are also vital devices for ensuring system safety in emergency situations.

[0002] However, many problems still need to be overcome in the use of control valves. When water or other fluids flow at high speed in a pipeline, they have a certain inertia. If the valve is suddenly closed, the fluid cannot stop immediately due to inertia, resulting in a sharp drop in flow velocity and generating a momentary high-pressure shock wave. The momentary high-pressure shock wave generated by the water hammer effect can cause the control valve to be subjected to pressures exceeding its design capacity, leading to mechanical fatigue, deformation, or even rupture of the valve body and internal components. It also accelerates the wear of seals and sealing surfaces, and the resulting vibrations can affect the operating mechanism and installation components, thereby reducing the valve's isolation function and increasing system leakage and safety hazards. Summary of the Invention

[0003] The purpose of this invention is to provide a control valve with water hammer reduction function to solve the problems mentioned in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a control valve with water hammer reduction function, comprising a valve body and a force transmission tube, a valve stem slidably mounted on the valve body, a valve core assembly mounted on the valve stem, an adjusting frame mounted on the valve body, a handwheel rotatably mounted on the adjusting frame, the handwheel being threadedly connected to the valve stem, a buffer assembly mounted on the inlet side of the valve body, a force transmission assembly mounted on the buffer assembly, one end of the force transmission tube communicating with the valve stem, and the other end of the force transmission tube communicating with the buffer assembly.

[0005] The valve stem is slidably connected to the valve body and can only slide up and down on the valve body. Since the handwheel is threadedly connected to the valve stem, when the handwheel is turned, the valve stem slides up and down by adjusting the thread.

[0006] When the control valve is in the open position, fluid enters the valve body from the pipeline through the buffer assembly, passes through the gap between the valve core assembly and the valve body, and then flows out from the valve body outlet. When flow regulation is required, rotating the handwheel causes the valve stem to slide up and down, which in turn moves the valve core assembly, changing the gap between the main valve core and the valve body. A larger gap increases the flow rate, while a smaller gap decreases the flow rate, thus achieving the purpose of flow regulation.

[0007] Furthermore, the valve core assembly includes a main valve core, which is mounted on the valve stem. A secondary valve core is slidably mounted inside the main valve core. A buffer spring is installed between the secondary valve core and the main valve core. The secondary valve core is connected to the valve stem. A compression chamber is provided inside the secondary valve core, and the compression chamber is filled with a compression medium. An opening and closing component is installed inside the main valve core, and an expansion airbag is installed on the main valve core.

[0008] When the control valve is suddenly shut off, the bottom of the valve core assembly is impacted by water hammer. After being impacted, the auxiliary valve core overcomes the spring force of the buffer spring and moves upward in the buffer chamber.

[0009] When the impact force is small, the secondary valve core moves slightly, and the deformation of the buffer spring absorbs part of the impact force, thereby reducing the water hammer impact force and achieving the purpose of primary water hammer reduction.

[0010] Furthermore, the main valve core is provided with a buffer chamber and a flow guide channel. One end of the flow guide channel is connected to the buffer chamber, and the other end of the flow guide channel is connected to the expansion airbag. The opening and closing assembly is located at the inlet of the flow guide channel. The auxiliary valve core is located in the buffer chamber. The main valve core is provided with a sliding groove, and the auxiliary valve core is slidably connected to the main valve core through the sliding groove.

[0011] Furthermore, the main valve core is also provided with a damping groove, the groove wall of which is provided with annular corrugations, the secondary valve core is provided with a wing ring, the bottom end of the buffer spring is connected to the wing ring, and the top end of the buffer spring is connected to the top end of the damping groove.

[0012] The annular corrugations in the damping groove are used to apply damping to the compressed buffer spring, delaying the rebound time of the buffer spring.

[0013] Furthermore, the opening and closing assembly includes a baffle located at the inlet of the flow channel, a wing plate on the baffle plate, and a return spring installed between the wing plate and the main valve core.

[0014] Under normal conditions, the baffle blocks the inlet of the guide channel.

[0015] When the fluid impact force is too large, the secondary valve core moves upward to the top of the buffer chamber under the impact force. The wing ring on the secondary valve core squeezes the buffer spring, and the buffer spring fully retracts into the damping groove. At the same time, when the wing ring moves to the height of the opening and closing assembly, it pushes the wing plate to move upward synchronously. The wing plate drives the baffle to lift upward, the inlet of the guide channel opens, the reset spring is compressed, and the fluid rushes into the expansion bladder from the guide channel. After the water flow is diverted, the impact on the valve core assembly is reduced, achieving the purpose of three-stage reduction of water hammer.

[0016] After the expansion bladder is filled with fluid, it expands rapidly. When the water hammer dissipates, the buffer spring in the damping groove cannot rebound immediately due to the damping effect of the annular corrugation. The secondary valve core remains at the top of the buffer chamber, and the guide channel remains open. At this time, the expansion bladder contracts rapidly, the fluid is squeezed out, and flows back into the valve body from the guide channel. Then the buffer spring gradually rebounds, and the secondary valve core is reset under the push of the buffer spring. The reset spring rebounds and drives the baffle to block the inlet of the guide channel again.

[0017] Furthermore, the valve stem is provided with an overflow channel, one end of which is connected to the compression chamber, and the other end of which is connected to the force transmission component through a force transmission tube. The valve stem is provided with an adjusting thread, and the valve stem is threadedly connected to the handwheel through the adjusting thread.

[0018] Furthermore, the force transmission component includes a force transmission housing, which is mounted on the buffer component. The force transmission housing has a liquid inlet, which is connected to the overflow channel through a force transmission pipe. A piston head is slidably installed inside the force transmission housing, and a force transmission bent rod is installed on the piston head. A connector is installed at one end of the force transmission bent rod, and the connector is connected to the buffer component.

[0019] When the impact is large, the secondary valve core undergoes a significant upward displacement, reducing the volume of the compression chamber within it. The compressed medium, under pressure, sequentially enters the transmission housing through the overflow pipe, transmission pipe, and inlet. This compressed medium pushes the piston head to make a curved displacement around the first transmission ring within the transmission housing. The piston head then drives the transmission rod to extend out of the transmission housing. The transmission rod, through a connector, causes the first transmission ring to deflect on the first buffer housing. The first transmission ring then drives the first buffer plate, which meshes with it, to unfold. The first transmission ring, through a transmission rod, drives the second transmission ring to deflect, causing the second buffer plate to unfold. The unfolded second buffer plate, along with the first buffer plate, provides step-by-step buffering for the fluid flowing towards the control valve. Simultaneously, the second and first buffer plates provide secondary buffering for the backflowing fluid after impacting the valve core, thus achieving a two-stage reduction of water hammer.

[0020] The greater the impact on the secondary valve core, the greater the upward displacement, and the greater the compressive pressure of the compressed medium on the piston head. The greater the deflection angle of the first and second transmission rings driven by the force transmission rod, the higher the expansion of the second and first buffer plates, and the greater the resistance of the second and first buffer plates to the fluid. This achieves the purpose of automatically adjusting the secondary reduction intensity according to the strength of the water hammer.

[0021] Furthermore, the buffer assembly includes a buffer tube installed on the inlet side of the valve body. A first buffer and a second buffer are provided on the buffer tube. A force transmission rod is installed between the first buffer and the second buffer. A force transmission housing is installed on the first buffer, and a connector is connected to the first buffer.

[0022] Furthermore, the first buffer includes a first buffer housing, which is mounted on a buffer tube. A force transmission housing is mounted on the first buffer housing. Several first buffer plates are rotatably mounted inside the first buffer housing. A first transmission ring is rotatably mounted on the force transmission housing. The first buffer plates mesh with the first transmission ring for transmission. A connecting piece is connected to the first transmission ring. A force transmission rod is connected to the first transmission ring. The first buffer plates are provided with transmission teeth. Several ring teeth are provided inside the first transmission ring. The transmission teeth mesh with the ring teeth for transmission.

[0023] Furthermore, the second buffer includes a second buffer housing, several second buffer plates, and a second transmission ring. The surface area of ​​the second buffer plates is smaller than that of the first buffer plates. The second transmission ring is connected to the force transmission rod. The second buffer housing is mounted on the buffer tube. The second buffer plates are rotatably mounted inside the second buffer housing. The second transmission ring is rotatably mounted on the second buffer housing. The second transmission ring meshes with the second buffer plates for transmission.

[0024] The first and second buffers have identical internal structures, differing only in surface area. When fluid flows over the deployed first and second buffers, its velocity decreases due to their obstruction. The larger the obstructing area of ​​the buffer, the greater the obstruction. The second buffer offers less resistance to the fluid than the first. By progressively obstructing the fluid through these buffers, the fluid velocity and flow rate are reduced, thus decreasing the impact force on the secondary valve core.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The kinetic energy generated by the fluid impact is converted into mechanical transmission energy by the deflection of the first and second transmission rings through a compression medium, ultimately achieving the purpose of deploying the buffer plates without external force. The synchronous deployment of the first and second buffer plates forms a double buffer barrier, effectively dispersing the water hammer impact energy. This provides both staged buffering of the forward-impacting fluid and secondary energy absorption of the reverse-flowing fluid, thus achieving a two-stage reduction of water hammer.

[0027] 2. Through the design of a variable volume compression chamber, the compression chamber can automatically adapt to the magnitude of the water hammer impact force, thereby causing the first and second buffer plates to adaptively expand to the corresponding angles according to the magnitude of the water hammer impact force, without the need for manual intervention and adjustment, achieving the purpose of automatically adjusting the secondary reduction intensity according to the strength of the water hammer.

[0028] 3. The flow channel is opened in conjunction with the displacement of the secondary valve core, enabling rapid diversion of the impacting fluid; the expansion bladder diverts excess fluid and buffers the fluid through its own deformation, achieving three-stage reduction of water hammer. The wing ring, wing plate, and baffle are linked to trigger the opening and closing of the flow channel, automatically achieving overload protection without external control.

[0029] 4. When the inflatable airbag retracts, it actively discharges fluid to achieve rapid fluid return; through the damping effect of the annular corrugation on the buffer spring, the secondary valve core is delayed in resetting, which not only ensures complete fluid return but also avoids the risk of secondary impact.

[0030] 5. The auxiliary valve core converts the water hammer impact into its own displacement, which in turn causes the buffer spring to compress and deform, absorbing the impact force and achieving the purpose of primary water hammer reduction. Attached Figure Description

[0031] Figure 1 is an overall perspective view of the control valve of the present invention;

[0032] Figure 2 is a perspective view of the control valve of the present invention;

[0033] Figure 3 is a perspective view of the buffer assembly and valve core assembly of the present invention;

[0034] Figure 4 is a perspective view of the valve core assembly of the present invention;

[0035] Figure 5 is a perspective view of the main valve core of the present invention;

[0036] Figure 6 is a partial enlarged view of region A in Figure 5 of the present invention;

[0037] Figure 7 is a perspective view of the wing ring of the present invention;

[0038] Figure 8 is a perspective view of the first buffer of the present invention;

[0039] Figure 9 is a perspective view of the first buffer sheet and the first transmission ring of the present invention;

[0040] Figure 10 is a perspective view of the force transmission component of the present invention.

[0041] In the diagram: 1. Valve body; 2. Adjusting bracket; 3. Handwheel; 4. Force transmission tube; 5. Buffer assembly; 6. Valve core assembly; 7. Valve stem; 8. Force transmission assembly; 51. Buffer tube; 52. First buffer; 53. Force transmission rod; 54. Second buffer; 71. Adjusting thread; 72. Overflow channel; 61. Main valve core; 62. Secondary valve core; 63. Buffer spring; 64. Inflation bladder; 65. Opening and closing assembly; 66. Compression chamber; 61 1. Flow guide channel; 612. Damping groove; 613. Sliding groove; 614. Buffer chamber; 651. Baffle; 652. Return spring; 653. Wing plate; 621. Wing ring; 521. First buffer shell; 522. First buffer plate; 523. First transmission ring; 5221. Transmission gear; 5231. Ring gear; 81. Force transmission shell; 82. Force transmission bent rod; 83. Piston head; 84. Connecting piece; 85. Liquid inlet. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] As shown in Figures 1-10, the present invention provides a control valve with water hammer reduction function: including a valve body 1 and a force transmission tube 4, a valve stem 7 is slidably mounted on the valve body 1, a valve core assembly 6 is mounted on the valve stem 7, an adjusting frame 2 is mounted on the valve body 1, a handwheel 3 is rotatably mounted on the adjusting frame 2, the handwheel 3 is threadedly connected to the valve stem 7, a buffer assembly 5 is mounted on the inlet side of the valve body 1, a force transmission assembly 8 is mounted on the buffer assembly 5, one end of the force transmission tube 4 is connected to the valve stem 7, and the other end of the force transmission tube 4 is connected to the buffer assembly 5.

[0044] The valve stem 7 is slidably connected to the valve body 1 and can only slide up and down on the valve body 1. Since the handwheel 3 is threadedly connected to the valve stem 7, when the handwheel 3 is rotated, the valve stem 7 is driven to slide up and down by adjusting the thread 71.

[0045] The valve core assembly 6 includes a main valve core 61, which is mounted on the valve stem 7. A secondary valve core 62 is slidably mounted inside the main valve core 61. A buffer spring 63 is installed between the secondary valve core 62 and the main valve core 61. The secondary valve core 62 is connected to the valve stem 7. A compression chamber 66 is provided inside the secondary valve core 62, which is filled with a compression medium. An opening and closing assembly 65 is installed inside the main valve core 61, and an expansion airbag 64 is installed on the main valve core 61.

[0046] The main valve core 61 is provided with a buffer chamber 614 and a flow guide channel 611. One end of the flow guide channel 611 is connected to the buffer chamber 614, and the other end of the flow guide channel 611 is connected to the expansion airbag 64. The opening and closing assembly 65 is located at the inlet of the flow guide channel 611. The auxiliary valve core 62 is located in the buffer chamber 614. The main valve core 61 is provided with a sliding groove 613. The auxiliary valve core 62 is slidably connected to the main valve core 61 through the sliding groove 613.

[0047] The main valve core 61 is also provided with a damping groove 612, and the groove wall of the damping groove 612 is provided with annular corrugations. The secondary valve core 62 is provided with a wing ring 621. The bottom end of the buffer spring 63 is connected to the wing ring 621, and the top end of the buffer spring 63 is connected to the top end of the damping groove 612. The annular corrugations in the damping groove 612 are used to apply damping to the compressed buffer spring 63, delaying the rebound time of the buffer spring 63.

[0048] The opening / closing assembly 65 includes a baffle 651 located at the inlet of the flow channel 611. A wing 653 is provided on the baffle 651, and a return spring 652 is installed between the wing 653 and the main valve core 61. Under normal conditions, the baffle 651 blocks the inlet of the flow channel 611.

[0049] The valve stem 7 is provided with an overflow channel 72. One end of the overflow channel 72 is connected to the compression chamber 66, and the other end of the overflow channel 72 is connected to the force transmission component 8 through the force transmission tube 4. The valve stem 7 is provided with an adjusting thread 71, and the valve stem 7 is threadedly connected to the handwheel 3 through the adjusting thread 71.

[0050] The force transmission assembly 8 includes a force transmission housing 81, which is mounted on the buffer assembly 5. The force transmission housing 81 is provided with a liquid inlet 85, which is connected to the overflow channel 72 through the force transmission pipe 4. A piston head 83 is slidably installed inside the force transmission housing 81. A force transmission bent rod 82 is installed on the piston head 83. A connector 84 is installed at one end of the force transmission bent rod 82, and the connector 84 is connected to the buffer assembly 5.

[0051] The buffer assembly 5 includes a buffer tube 51, which is installed on the inlet side of the valve body 1. A first buffer 52 and a second buffer 54 are provided on the buffer tube 51. A force transmission rod 53 is installed between the first buffer 52 and the second buffer 54. A force transmission housing 81 is installed on the first buffer 52. A connector 84 is connected to the first buffer 52.

[0052] The first buffer 52 includes a first buffer housing 521, which is mounted on the buffer tube 51. A force transmission housing 81 is mounted on the first buffer housing 521. Several first buffer plates 522 are rotatably mounted inside the first buffer housing 521. A first transmission ring 523 is rotatably mounted on the force transmission housing 81. The first buffer plates 522 and the first transmission ring 523 mesh and transmit power. A connecting piece 84 is connected to the first transmission ring 523. A force transmission rod 53 is connected to the first transmission ring 523. The first buffer plates 522 are provided with transmission teeth 5221. The first transmission ring 523 is provided with several ring teeth 5231. The transmission teeth 5221 and the ring teeth 5231 mesh and transmit power.

[0053] The second buffer 54 includes a second buffer housing, several second buffer plates, and a second transmission ring. The surface area of ​​the second buffer plates is smaller than that of the first buffer plate 522. The second transmission ring is connected to the force transmission rod 53. The second buffer housing is mounted on the buffer tube 51. The second buffer plates are rotatably mounted inside the second buffer housing. The second transmission ring is rotatably mounted on the second buffer housing. The second transmission ring meshes with the second buffer plates for transmission.

[0054] The first buffer 52 and the second buffer 54 have the same internal structure, with the only difference being the surface area of ​​the first buffer plate 522 and the second buffer plate. When the fluid flows through the deployed first buffer plate 522 and the second buffer plate, the flow velocity decreases after being blocked by the first buffer plate 522 and the second buffer plate. The larger the blocking area of ​​the buffer plate, the greater the obstruction to the fluid. The resistance of the second buffer plate to the fluid is less than that of the first buffer plate 522. The first buffer plate 522 and the second buffer plate block the fluid step by step. After the fluid velocity and flow rate are reduced, the impact force on the secondary valve core 62 is reduced.

[0055] The working principle of this invention is as follows: When the control valve is in the open state, fluid enters the valve body 1 from the pipeline through the buffer assembly 5, passes through the gap between the valve core assembly 6 and the valve body 1, and then flows out from the outlet of the valve body 1. When flow regulation is required, rotating the handwheel 3 causes the valve stem 7 to slide up and down. The valve stem 7 moves the valve core assembly 6, changing the gap between the main valve core 61 and the valve body 1. A larger gap increases the flow rate, and a smaller gap decreases the flow rate, thereby achieving the purpose of flow regulation.

[0056] When the control valve suddenly shuts off, the bottom of the valve core assembly 6 is impacted by water hammer. After being impacted, the auxiliary valve core 62 overcomes the elastic force of the buffer spring 63 and moves upward within the buffer chamber 614. When the impact force is small, the auxiliary valve core 62 moves slightly, absorbing part of the impact force through the deformation of the buffer spring 63, thereby reducing the water hammer impact force and achieving the purpose of primary water hammer reduction.

[0057] When the impact is large, the secondary valve core 62 displaces upward, reducing the volume of the compression chamber 66 within it. The compressed medium, after being compressed, enters the force transmission housing 81 sequentially through the overflow pipe, the force transmission pipe 4, and the inlet 85. The compressed medium pushes the piston head 83 to make a curved displacement around the first transmission ring 523 within the force transmission housing 81. The piston head 83 drives the force transmission bent rod 82 to extend out of the force transmission housing 81. The force transmission bent rod 82, through the connector 84, drives the first transmission ring 523 to deflect on the first buffer housing 521. The first transmission ring 523 drives the first buffer plate 522, which meshes with it, to unfold. The first transmission ring 523, through the force transmission rod 53, drives the second transmission ring to deflect, and the second transmission ring drives the second buffer plate to unfold. The unfolded second buffer plate and the first buffer plate 522 provide step-by-step buffering for the fluid flowing to the control valve. Simultaneously, the second buffer plate and the first buffer plate 522 provide secondary buffering for the fluid that flows back after impacting the valve core, thereby achieving the purpose of secondary reduction of water hammer.

[0058] The greater the impact on the auxiliary valve core 62, the greater the upward displacement, and the greater the compressive pressure of the compressed medium on the piston head 83. The greater the deflection angle of the first transmission ring 523 and the second transmission ring driven by the force transmission rod 82, the higher the expansion degree of the second buffer plate and the first buffer plate 522, which makes the resistance of the second buffer plate and the first buffer plate 522 to the fluid greater, thereby achieving the purpose of automatically adjusting the secondary reduction intensity according to the strength of the water hammer.

[0059] When the fluid impact force is too large, the secondary valve core 62 moves upward to the top of the buffer chamber 614 under the impact force. The wing ring 621 on the secondary valve core 62 squeezes the buffer spring 63, and the buffer spring 63 is fully contracted into the damping groove 612. At the same time, when the wing ring 621 moves to the height of the opening and closing assembly 65, it pushes the wing plate 653 to move upward synchronously. The wing plate 653 drives the baffle 651 to lift upward, the inlet of the guide channel 611 opens, the reset spring 652 is compressed, and the fluid rushes into the expansion air bag 64 from the guide channel 611. After the water flow is diverted, the impact on the valve core assembly 6 is reduced, achieving the purpose of three-stage reduction of water hammer.

[0060] After the expansion bladder 64 is filled with fluid, it expands rapidly. When the water hammer dissipates, the buffer spring 63 in the damping groove 612 is damped by the annular corrugation and cannot rebound immediately. The secondary valve core 62 is still located at the top of the buffer chamber 614, and the guide channel 611 remains open. At this time, the expansion bladder 64 retracts rapidly, the fluid is squeezed out and flows back into the valve body 1 from the guide channel 611. Then the buffer spring 63 gradually rebounds, and the secondary valve core 62 is reset under the push of the buffer spring 63. The reset spring 652 rebounds and drives the baffle 651 to block the inlet of the guide channel 611 again.

[0061] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A control valve with water hammer reduction function, characterized in that: The control valve includes a valve body (1) and a force transmission tube (4). A valve stem (7) is slidably mounted on the valve body (1). A valve core assembly (6) is mounted on the valve stem (7). An adjusting frame (2) is mounted on the valve body (1). A handwheel (3) is rotatably mounted on the adjusting frame (2). The handwheel (3) is threadedly connected to the valve stem (7). A buffer assembly (5) is mounted on the inlet side of the valve body (1). A force transmission assembly (8) is mounted on the buffer assembly (5). One end of the force transmission tube (4) is connected to the valve stem (7), and the other end of the force transmission tube (4) is connected to the buffer assembly (5).

2. A control valve with water hammer reduction function according to claim 1, characterized in that: The valve core assembly (6) includes a main valve core (61), which is mounted on the valve stem (7). A secondary valve core (62) is slidably installed inside the main valve core (61). A buffer spring (63) is installed between the secondary valve core (62) and the main valve core (61). The secondary valve core (62) is connected to the valve stem (7). A compression chamber (66) is provided inside the secondary valve core (62). The compression chamber (66) is filled with a compression medium. An opening and closing assembly (65) is installed inside the main valve core (61). An expansion airbag (64) is installed on the main valve core (61).

3. A control valve with water hammer reduction function according to claim 2, characterized in that: The main valve core (61) is provided with a buffer chamber (614) and a flow guide channel (611). One end of the flow guide channel (611) is connected to the buffer chamber (614), and the other end of the flow guide channel (611) is connected to the inflatable airbag (64). The opening and closing assembly (65) is located at the entrance of the flow guide channel (611). The secondary valve core (62) is located in the buffer chamber (614). The main valve core (61) is provided with a sliding groove (613). The secondary valve core (62) is slidably connected to the main valve core (61) through the sliding groove (613).

4. A control valve with water hammer reduction function according to claim 3, characterized in that: The main valve core (61) is also provided with a damping groove (612), the damping groove (612) has annular corrugations on its groove wall, the secondary valve core (62) is provided with a wing ring (621), the bottom end of the buffer spring (63) is connected to the wing ring (621), and the top end of the buffer spring (63) is connected to the top end of the damping groove (612).

5. A control valve with water hammer reduction function according to claim 3, characterized in that: The opening and closing assembly (65) includes a baffle (651) located at the inlet of the guide channel (611). The baffle (651) is provided with a wing plate (653), and a return spring (652) is installed between the wing plate (653) and the main valve core (61).

6. A control valve with water hammer reduction function according to claim 2, characterized in that: The valve stem (7) is provided with an overflow channel (72). One end of the overflow channel (72) is connected to the compression chamber (66), and the other end of the overflow channel (72) is connected to the force transmission assembly (8) through the force transmission tube (4). The valve stem (7) is provided with an adjusting thread (71), and the valve stem (7) is threadedly connected to the handwheel (3) through the adjusting thread (71).

7. A control valve with water hammer reduction function according to claim 6, characterized in that: The force transmission component (8) includes a force transmission housing (81), which is mounted on the buffer component (5). The force transmission housing (81) is provided with a liquid inlet (85), which is connected to the overflow channel (72) through the force transmission tube (4). A piston head (83) is slidably installed inside the force transmission housing (81), and a force transmission bent rod (82) is installed on the piston head (83). A connector (84) is installed at one end of the force transmission bent rod (82), and the connector (84) is connected to the buffer component (5).

8. A control valve with water hammer reduction function according to claim 7, characterized in that: The buffer assembly (5) includes a buffer tube (51), which is installed on the inlet side of the valve body (1). The buffer tube (51) is provided with a first buffer (52) and a second buffer (54). A force transmission rod (53) is installed between the first buffer (52) and the second buffer (54). The force transmission housing (81) is installed on the first buffer (52). The connector (84) is connected to the first buffer (52).

9. A control valve with water hammer reduction function according to claim 8, characterized in that: The first buffer (52) includes a first buffer housing (521), which is mounted on a buffer tube (51). A force transmission housing (81) is mounted on the first buffer housing (521). A plurality of first buffer plates (522) are rotatably mounted inside the first buffer housing (521). A first transmission ring (523) is rotatably mounted on the force transmission housing (81). The first buffer plates (522) and the first transmission ring (523) mesh and drive each other. The connecting piece (84) is connected to the first transmission ring (523). The force transmission rod (53) is connected to the first transmission ring (523). The first buffer plate (522) is provided with transmission teeth (5221). The first transmission ring (523) is provided with a plurality of ring teeth (5231). The transmission teeth (5221) and the ring teeth (5231) mesh and drive each other.

10. A control valve with water hammer reduction function according to claim 9, characterized in that: The second buffer (54) includes a second buffer housing, several second buffer plates and a second transmission ring. The surface area of ​​the second buffer plate is smaller than that of the first buffer plate (522). The second transmission ring is connected to the force transmission rod (53). The second buffer housing is installed on the buffer tube (51). The second buffer plate is rotatably installed inside the second buffer housing. The second transmission ring is rotatably installed on the second buffer housing. The second transmission ring meshes with the second buffer plate for transmission.

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