A pneumatic ultra-clean diaphragm valve with adjustable flow

Abstract

The present invention discloses an adjustable flow pneumatic ultra-clean diaphragm valve in the semiconductor field. A diaphragm is provided in the valve cavity connecting the inlet and outlet of the valve body. The upper end of the diaphragm is fixed to the lower end of the piston rod. The upper cavity and the lower cavity are sealed and fixedly connected and enclose an air chamber inside. The upper part of the piston rod can be sealed and installed in the air chamber in a movable direction toward or away from the valve cavity. The lower part of the piston rod extends out of the air chamber and is fixedly installed on the lower cavity of the valve body. The side wall of the lower cavity is provided with a flow regulating structure for controlling the equilibrium position of the diaphragm. The flow regulating structure is used to connect the air chamber and the atmosphere. The lower cavity is provided with air holes for cooperating with the flow regulating structure to adjust the equilibrium position of the diaphragm and thus control the opening of the valve body. The present invention can accurately adjust the flow rate and has excellent sealing performance, avoiding the entry of pollutants outside the valve and the leakage of the fluid transported in the valve. The diaphragm valve is made of PTTE material as a whole, which can meet the requirements of corrosion resistance, heat resistance and high cleanliness.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a pneumatic ultra-clean diaphragm valve with adjustable flow rate, which serves as a main component in the storage and transportation process of ultra-pure media. Background Art

[0002] Ultra-clean diaphragm valves, as precision fluid control components, play a vital role in many high-tech industries and are widely used in fields such as semiconductor manufacturing, biomedicine, and fine chemicals. Diaphragm valves separate the fluid from the outside world through a flexible diaphragm. A drive mechanism is installed within the valve cover and connected to the diaphragm. This mechanism drives the transmission element in a linear motion, raising and lowering the diaphragm, thereby regulating the valve's opening and closing.

[0003] Existing pneumatic ultra-clean diaphragm valves only function as switches during the storage and transport of ultrapure media. The diaphragm valve has two chambers, one upper and one lower. During opening and closing, compressed air is introduced into the corresponding chamber, while the other chamber is exhausted, enabling the diaphragm to move. The chambers lack internal limiters, allowing compressed air to flow continuously until the piston rod contacts the upper and lower inner surfaces of the chambers. At this point, the chamber volume no longer changes, and the diaphragm stops moving. Therefore, the diaphragm valve has only two states: fully open and fully closed. The opening cannot be adjusted, and the flow control system requires the installation of additional components to control the flow. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a pneumatic ultra-clean diaphragm valve with adjustable flow rate, which realizes flow rate regulation and prevents the entry of pollutants outside the valve and the leakage of the fluid transported in the valve.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0006] The present invention includes an upper cavity, a lower cavity, a diaphragm, a piston rod and a flow regulating switch; a diaphragm is provided in the valve cavity connecting the inlet and outlet of the valve body, the upper end of the diaphragm is fixed to the lower end of the piston rod, the upper cavity and the lower cavity are sealed and fixedly connected and form an air chamber inside, the upper part of the piston rod can be sealed and installed in the air chamber in a movable direction toward or away from the valve cavity, the lower part of the piston rod extends out of the air chamber and is fixedly installed on the lower cavity of the valve body, the side wall of the lower cavity is provided with a flow regulating structure for controlling the equilibrium position of the diaphragm, the flow regulating structure is used to connect the air chamber and the atmosphere, and the lower cavity is provided with air holes for cooperating with the flow regulating structure to adjust the equilibrium position of the diaphragm and thereby control the opening of the valve body.

[0007] The flow regulating structure includes a flow regulating switch and a flow regulating hole arranged on the side wall of the lower cavity. The flow regulating switch is rotatably and adjustable sealedly installed on the outer side wall of the lower cavity by bolts. A plurality of flow regulating holes are provided on the surface of the side wall of the lower cavity opposite to the flow regulating switch, which are spaced apart and connected to the air chamber in the lower cavity. The plurality of flow regulating holes are spaced apart along a circular arc from top to bottom and around the horizontal rotation center axis of the flow regulating switch. A connecting hole is provided on the flow regulating switch for connecting with the flow regulating hole after the flow regulating switch rotates, and the connecting hole is connected to the atmosphere.

[0008] The radial distance of the communicating through hole relative to the rotation center axis of the flow regulating switch is the same as the radial distance of the flow regulating hole relative to the rotation center axis of the flow regulating switch.

[0009] An air inlet is provided at the top of the air chamber in the upper cavity, and an air outlet is provided at the bottom of the air chamber in the lower cavity.

[0010] The air outlet and the flow regulating switch are located on different sides of the lower cavity.

[0011] A vertical limiting baffle is provided in the middle of the air chamber in the upper cavity, and the top end of the limiting baffle is fixed to the top surface of the air chamber.

[0012] The upper cavity, lower cavity and valve body are respectively provided with mounting through holes, and the upper cavity, lower cavity and valve body are connected together after bolts are sequentially passed through the mounting through holes respectively provided in the upper cavity, lower cavity and valve body.

[0013] The valve body is provided with a fluid inlet at one end and a fluid outlet at the other end. The fluid inlet and the fluid outlet are respectively connected to the two sides of the valve cavity. A weir is provided in the valve cavity for contacting and sealing with the lower surface of the diaphragm.

[0014] The lower cavity has a mounting screw hole on the outer wall opposite to the rotation center axis of the flow regulating switch. The flow regulating switch has a countersunk hole on the rotation center axis. The bolt passes through the countersunk hole of the flow regulating switch and is threaded into the mounting screw hole.

[0015] The outer edge of the flow regulating switch is provided with a protruding portion, the outer wall of the lower cavity is provided with a protrusion, the protrusion is provided with a mounting hole for installing the flow regulating switch, the hole wall of the mounting hole is provided with a groove, and the outer edge of the flow regulating switch is provided with a protruding portion for fitting into the groove.

[0016] In the present invention, the diaphragm valve is equipped with a piston rod in the valve cover, and the valve cover and the valve body are separated by a diaphragm. The diaphragm is pulled up and pressed down by the linear motion of the piston rod, thereby completing the opening and closing adjustment of the valve; when working, gases with the same pressure are introduced into the upper and lower chambers, and by adjusting the flow adjustment switch, different adjustment holes are connected to the outside, the pressure in the upper chamber drops, and a pressure difference is formed, thereby driving the piston rod to move and stay at different positions to achieve the function of flow regulation.

[0017] The technical solution provided by the present invention has the following effects:

[0018] The present invention utilizes a flow control switch to adjust the flow rate in stages. Before operation, the flow control switch must be adjusted to the appropriate position to connect the desired flow control holes. During operation, the pressure in the upper and lower air chambers remains constant. Because the piston rod stops at different positions due to the different connected flow control holes, the diaphragm expands and contracts to varying degrees, varying the valve opening and thus adjusting the flow rate.

[0019] Compared with the existing technology, the present invention can accurately adjust the flow rate and has excellent sealing performance, avoiding the entry of pollutants outside the valve and the leakage of the fluid transported in the valve; the diaphragm valve is made of PTTE material as a whole, which can meet the requirements of corrosion resistance, heat resistance and high cleanliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To illustrate the embodiments of the present invention in more detail, the following briefly describes the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below are merely embodiments of the present invention, and those skilled in the art can derive other drawings based on the provided drawings without inventive effort.

[0021] Figure 1 An overall cross-sectional view provided for an embodiment of the present invention;

[0022] Figure 2 1 is an overall top view of the diaphragm valve in an embodiment of the present invention;

[0023] Figure 3 This is a structural diagram of the flow regulating switch and related parts of the lower cavity in an embodiment of the present invention.

[0024] In the figure: upper cavity 110, lower cavity 120, diaphragm 130, piston rod 140, valve body 150, flow regulating switch 160;

[0025] Upper cavity 110: air inlet 111, upper mounting through hole 112, limit baffle 113, sealing groove 114;

[0026] Lower cavity 120: air outlet 121, flow regulating hole 122, mounting screw hole 123, lower mounting through hole 124;

[0027] Piston rod 140: sealing groove 141;

[0028] The valve body 150 includes a fluid inlet 151, a weir portion 152, a fluid outlet 153, and a valve body mounting through hole 154;

[0029] The flow regulating switch 160 includes a communicating through hole 161 , a countersunk hole 162 , and a sealing groove 163 . DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, an embodiment of the present invention provides a pneumatic ultra-clean diaphragm valve with adjustable flow.

[0032] The main body of the diaphragm valve 100 includes an upper chamber 110, a lower chamber 120, a diaphragm 130, a piston rod 140, a valve body 150, and a flow control switch 160. The upper chamber 110 includes an air inlet 111, a mounting hole 112, a stopper 113, and a sealing groove 114. The lower chamber 120 includes an air outlet 121, a flow control hole 122, a mounting screw hole 123, and a mounting hole 124. The piston rod 140 includes a sealing groove 141. The valve body 150 includes a fluid inlet 151, a weir 152, a fluid outlet 153, and a mounting hole 154. The flow control switch 160 includes a connecting hole 161, a countersunk hole 162, and a sealing groove 163.

[0033] More specifically, as for the framework, Figure 1As shown, it includes an upper cavity 110, a lower cavity 120, a diaphragm 130, a piston rod 140 and a flow regulating switch 160; the valve body 150 is provided with an inlet, an outlet and a valve cavity, the two ends of the valve cavity are respectively connected to the inlet and the outlet, the valve cavity is provided with a valve core, and the valve cavity of the valve body 150 that connects the inlet and outlet is provided with a diaphragm 130, the upper end of the diaphragm 130 is fixed to the lower end of the piston rod 140, the upper cavity 110 and the lower cavity 120 are sealed and fixedly connected and form an air chamber inside, the upper part of the piston rod 140 can be sealed and installed in the air chamber so as to be movable toward or away from the valve cavity, and the lower part of the piston rod 140 extends out of the air chamber and is fixedly connected to the upper end of the diaphragm 130. The lower cavity 120 is sealed and fixed on the valve body 150. The side wall of the lower cavity 120 is provided with a flow regulating structure for controlling the equilibrium position of the diaphragm 130. The flow regulating structure is used to connect the air chamber and the atmosphere. The lower cavity 120 is provided with air holes for cooperating with the flow regulating structure to adjust the equilibrium position of the diaphragm 130 and thereby control the flow and opening of the valve body 150.

[0034] The upper and lower chambers 110 and 120 form two air chambers, separated by a piston rod 140. The piston rod 140 is mounted within the lower chamber 120, and the two chambers are fitted with a clearance fit. Sealing grooves 141 and 114 seal the upper and lower chambers. A stopper 113 limits the upward movement of the piston rod 140. The bottom of the piston rod 140 is connected to the diaphragm 130, which separates the valve body 150 from the lower chamber 120.

[0035] like Figure 3 As shown, the flow regulating structure includes a flow regulating switch 160 and a flow regulating hole 122 provided on the side wall of the lower cavity 120. The flow regulating switch 160 is rotatably and adjustable sealedly mounted on the outer side wall of the lower cavity 120 by bolts. A plurality of flow regulating holes 122 are provided on the side wall surface of the lower cavity 120 facing the flow regulating switch 160. The plurality of flow regulating holes 122 are spaced apart and connected to the air chamber in the lower cavity 120. The plurality of flow regulating holes 122 are spaced apart on the side wall surface of the lower cavity 120 along an arc from top to bottom and around the horizontal rotation center axis of the flow regulating switch 160.

[0036] The flow regulating switch 160 is provided with a communication hole 161 for communicating with the flow regulating hole 122 after the flow regulating switch 160 rotates, and the communication hole 161 is communicated with the atmosphere.

[0037] The radial distance of the connecting hole 161 relative to the rotation center axis of the flow regulating switch 160 is the same as the radial distance of the flow regulating hole 122 relative to the rotation center axis of the flow regulating switch 160, so that after the flow regulating switch 160 itself rotates to a certain extent, the connecting hole 161 and the flow regulating hole 122 are opposite and connected.

[0038] An air inlet 111 is formed at the top of the air chamber in the upper cavity 110 , and an air outlet 121 is formed at the bottom of the air chamber in the lower cavity 120 .

[0039] The air outlet 121 and the flow regulating switch 160 are located on different sides of the lower cavity 120 , specifically, on both sides of the lower cavity 120 .

[0040] A vertical limiting baffle 113 is provided in the middle of the air chamber in the upper cavity 110 , and the top end of the limiting baffle 113 is fixed to the top surface of the air chamber.

[0041] The upper cavity 110, the lower cavity 120 and the valve body 150 are each provided with a mounting through hole. Bolts are passed through the mounting through holes of the upper cavity 110, the lower cavity 120 and the valve body 150 in sequence to connect the upper cavity 110, the lower cavity 120 and the valve body 150 together.

[0042] like Figure 2 As shown, the upper chamber 110, the lower chamber 120, and the valve body 150 all have mounting holes. These four mounting holes are symmetrically arranged at the four corners, and all three are connected and fixed by their own long bolts. In a specific implementation, the upper chamber 110 has upper mounting holes 112 at each corner, the lower chamber 120 has lower mounting holes 124 at each corner, and the valve body 150 has valve body mounting holes 154 at each corner. The mounting holes at the four corners of the upper chamber 110, the lower chamber 120, and the valve body 150 are aligned. Bolts are sequentially passed through the upper mounting holes 112 of the upper chamber 110 and the lower mounting holes 124 of the lower chamber 120 from top to bottom, and then screwed into the valve body mounting holes 154 of the valve body 150, thereby connecting the upper chamber 110, the lower chamber 120, and the valve body 150 together.

[0043] A sealing groove 114 is formed on the mating surface between the upper cavity 110 and the lower cavity 120 , and a sealing ring is installed in the sealing groove 114 .

[0044] The piston rod 140 has at least one sealing groove 141 on its outer circumference that cooperates with the lower cavity 120. A sealing ring is installed in the sealing groove 141. In a specific implementation, one sealing groove 141 can be provided on the upper and lower sides to strengthen the seal.

[0045] At least one sealing groove 163 is formed on the surface of the flow regulating switch 160 that cooperates with the outer wall of the lower cavity 120 , and a sealing ring is installed in the sealing groove 163 .

[0046] A fluid inlet 151 is provided at one end of the valve body 150, and a fluid outlet 153 is provided at the other end. The fluid inlet 151 and the fluid outlet 153 are respectively connected to the two sides of the valve cavity. A weir portion 152 is provided in the valve cavity. The weir portion 152 is used to contact and seal with the lower surface of the diaphragm 130. When the lower surface of the diaphragm 130 is in contact and sealing connection with the weir portion, the valve body 150 is closed.

[0047] The fluid inlet 151 and the fluid outlet 153 are connected to the weir portion 152 , and the diaphragm 130 is installed directly above the weir portion 152 . In a specific implementation, the groove on the outer ring of the diaphragm 130 cooperates with the protrusion of the valve body 150 to achieve sealing.

[0048] The lower cavity 120 has a mounting screw hole 123 on the outer wall opposite to the rotation center axis of the flow regulating switch 160. The flow regulating switch 160 has a countersunk hole 162 on the rotation center axis. The mounting screw hole 123 and the countersunk hole 162 are coaxially arranged. The bolt passes through the countersunk hole 162 of the flow regulating switch 160 and is threadedly connected to the mounting screw hole 123.

[0049] A groove is provided on the lower cavity along the radial direction of the flow regulating hole, and the flow regulating switch has a corresponding protrusion along the radial direction of the through hole, which is used to achieve precise correspondence between the through hole and the flow regulating hole when installing the flow regulating switch.

[0050] More specifically, if Figure 3 As shown, the flow regulating switch 160 is provided with a protruding portion on the outer edge, and a protrusion is provided on the outer wall of the lower cavity 120. The protrusion is provided with an installation hole for installing the flow regulating switch 160. The hole wall of the installation hole is provided with a groove. The flow regulating switch 160 is provided with a protruding portion on the outer edge for fitting into the groove.

[0051] In a specific implementation, the air inlet 111 and the air outlet 121 are respectively connected to an external air pressure source, and the air pressure of the external air pressure source is usually stable.

[0052] When flow regulation is not considered, by adjusting the gas pressure entering the air inlet 111 and the air outlet 121, the upper and lower pressure difference of the piston rod 140 is changed, the piston rod 140 is pushed up and down, and the expansion and contraction degree of the diaphragm 130 is changed, thereby affecting the contact degree and distance between the diaphragm 130 and the weir 152, thereby realizing the full opening and closing of the diaphragm valve.

[0053] When the diaphragm valve is fully closed, the bottom end of the diaphragm 130 presses against the weir 152 to form a seal, thereby closing the diaphragm valve. Fluid flowing in from the fluid inlet 151 is blocked by the weir 152 and cannot flow out from the fluid outlet 153. When the diaphragm valve is open, the bottom end of the diaphragm 130 leaves the weir 152 to form a gap, breaking the seal. The diaphragm valve is then opened, allowing fluid to flow in from the fluid inlet 151, pass through the gap between the weir 152 and the diaphragm 130, and flow into the fluid outlet 153.

[0054] When the flow rate and opening need to be adjusted and controlled, the connecting hole 161 needs to be connected to the appropriate flow regulating hole 122 so that the flow regulating hole 122 is connected to the atmosphere through the connecting hole 161, because there is a pressure difference between the air chambers on the upper and lower sides of the piston rod 140.

[0055] like Figure 1 As shown, the pressure difference is controlled by the flow regulating structure and the air holes opened in the lower cavity 120 in the following manner:

[0056] Initially, the air pressure in the air chamber above the piston rod 140 is greater than the air pressure in the air chamber below the piston rod 140 , and the top of the piston rod 140 is located below the flow regulating hole 122 .

[0057] Next, after the flow regulating hole 122 is connected to the atmosphere, the flow regulating hole 122 is now connected to the upper air chamber, causing the air pressure in the upper air chamber connected to the flow regulating hole 122 to decrease, while the air pressure in the lower air chamber remains unchanged. The air pressure in the lower air chamber then pushes the piston rod 140 toward the upper air chamber until the air pressure in the upper and lower air chambers is balanced or the piston rod 140 moves above the flow regulating hole 122.

[0058] Then, after the piston rod 140 moves to above the flow regulating hole 122, the flow regulating hole 122 and the lower air chamber are connected, which drives the air pressure of the lower air chamber connected to the flow regulating hole 122 to decrease, which will make the air pressure in the upper air chamber of the piston rod 140 greater than the air pressure in the lower air chamber of the piston rod 140, and then the air pressure in the upper air chamber pushes the piston rod 140 to move toward the lower air chamber until the air pressure in the upper air chamber and the lower air chamber is balanced or the piston rod 140 moves below the flow regulating hole 122.

[0059] Therefore, after the flow regulating hole 122 is connected to the atmosphere, the piston rod 140 will move back and forth up and down, and finally stop at the flow regulating hole 122 connected to the atmosphere, thereby adjusting the balance position of the piston rod 140, and then adjusting the degree of expansion and contraction of the diaphragm 130 at the lower end of the piston rod 140, thereby controlling the valve opening and flow of the diaphragm valve.

[0060] like Figure 3 As shown, when communication hole 161 is connected to the corresponding flow regulating hole 122, the protrusion on flow regulating switch 160 and the groove in lower chamber 120 interlock and position, achieving accurate switching. Bolts are then passed through countersunk holes 162 and mounting screw holes 123 to tightly assemble the flow regulating switch to lower chamber 120. A sealing ring is installed in sealing groove 163 to maintain a fixed valve opening and flow rate, and to achieve a gas seal.

[0061] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A pneumatic ultra-clean diaphragm valve with adjustable flow, comprising a valve body (150), characterized in that: The valve body (150) comprises an upper cavity (110), a lower cavity (120), a diaphragm (130), a piston rod (140) and a flow regulating switch (160); a diaphragm (130) is provided in the valve cavity communicating with the inlet and outlet of the valve body (150); the upper end of the diaphragm (130) is fixed to the lower end of the piston rod (140); the upper cavity (110) and the lower cavity (120) are sealed and fixedly connected and enclose an air chamber inside; the upper part of the piston rod (140) is sealed and mounted on the valve cavity so as to be movable in a direction toward or away from the valve cavity. In the air chamber, the lower portion of the piston rod (140) extends out of the air chamber, and the lower cavity (120) is fixedly mounted on the valve body (150). The side wall of the lower cavity (120) is provided with a flow regulating structure for controlling the equilibrium position of the diaphragm (130). The flow regulating structure is used to connect the air chamber with the atmosphere. The lower cavity (120) is provided with air holes on both upper and lower sides of the piston relative to the piston rod (140) for cooperating with the flow regulating structure to adjust the equilibrium position of the diaphragm (130) and thereby control the opening of the valve body (150). The flow regulating structure includes a flow regulating switch (160) and a flow regulating hole (122) provided on the side wall of the lower cavity (120); the flow regulating switch (160) is rotatably and adjustable sealedly mounted on the outer side wall of the lower cavity (120) by means of bolts; a plurality of flow regulating holes (122) are provided on the side wall surface of the lower cavity (120) facing the flow regulating switch (160), which are spaced apart and connected to the air chamber in the lower cavity (120); the plurality of flow regulating holes (122) are spaced apart along a circular arc from top to bottom and around the horizontal rotation center axis of the flow regulating switch (160); The flow regulating switch (160) is provided with a communication hole (161) for communicating with the flow regulating hole (122) after the flow regulating switch (160) rotates, and the communication hole (161) is in communication with the atmosphere; An air inlet (111) is provided at the top of the air chamber in the upper cavity (110), and an air outlet (121) is provided at the bottom of the air chamber in the lower cavity (120).

2. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: The radial distance of the communication through hole (161) relative to the rotation center axis of the flow regulating switch (160) is the same as the radial distance of the flow regulating hole (122) relative to the rotation center axis of the flow regulating switch (160).

3. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: The air outlet (121) and the flow regulating switch (160) are located on different sides of the lower cavity (120).

4. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: A vertical limiting baffle (113) is provided in the middle of the air chamber in the upper cavity (110), and the top end of the limiting baffle (113) is fixed to the top surface of the air chamber.

5. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: The upper cavity (110), the lower cavity (120) and the valve body (150) are each provided with a mounting through hole, and bolts are sequentially passed through the mounting through holes respectively provided in the upper cavity (110), the lower cavity (120) and the valve body (150) to connect the upper cavity (110), the lower cavity (120) and the valve body (150) together.

6. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: The valve body (150) is provided with a fluid inlet (151) at one end and a fluid outlet (153) at the other end. The fluid inlet (151) and the fluid outlet (153) are respectively connected to two sides of the valve cavity. A weir portion (152) is provided in the valve cavity. The weir portion (152) is used to contact and seal with the lower surface of the diaphragm (130).

7. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: The lower cavity (120) is provided with a mounting screw hole (123) on an outer wall directly opposite to the rotation center axis of the flow regulating switch (160), and the flow regulating switch (160) is provided with a countersunk hole (162) on the rotation center axis, and a bolt passes through the countersunk hole (162) of the flow regulating switch (160) and is threadedly connected to the mounting screw hole (123).

8. The flow-adjustable pneumatic ultra-clean diaphragm valve according to claim 1, characterized in that: The flow regulating switch (160) is provided with a protruding portion on its outer edge, the outer wall of the lower cavity (120) is provided with a protrusion, the protrusion is provided with a mounting hole for mounting the flow regulating switch (160), the hole wall of the mounting hole is provided with a groove, and the flow regulating switch (160) is provided with a protruding portion on its outer edge for fitting into the groove.

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