Metal diaphragm valve

Abstract

The metal diaphragm valve comprises a valve body, a valve seat, a diaphragm and an actuator, the actuator comprises a shell, a piston rod, a first piston and a second piston, the first end of the first piston elastically abuts against a spring, a first driving air cavity is formed in the second axial side of the first piston, and a second driving air cavity is formed in the second axial side of the second piston. The first piston can be driven to axially slide towards the spring relative to the piston rod by inflating the first driving air cavity so as to compress the spring. The first piston is arranged to be of a structure capable of axially sliding between the protruding part and the spring relative to the piston rod, so that when the second flow dividing channel is blocked and the second piston cannot work, the first piston can be independently pushed by gas to move towards the spring so as to overcome the thrust applied to the piston rod by the spring; the elastic force of the diaphragm is enough to overcome the pressure applied to the diaphragm by the piston rod to open the valve seat, the situation that the diaphragm cannot be opened or cannot be opened to the maximum degree is avoided, and stable opening and closing of the diaphragm to the valve seat are achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of semiconductor valves, and particularly relates to a metal diaphragm valve. BACKGROUND

[0002] In atomic layer deposition technology (ALD) in a semiconductor manufacturing process, gas is supplied in a small amount. In order to supply the gas in a small amount with good precision, a metal diaphragm valve needs to be used. In ALD, a high-temperature gas of about 200 DEG C, such as liquefied titanium (boiling point 160 DEG C), can be supplied. In order to withstand the high-temperature gas, a metal diaphragm made of nickel-cobalt alloy with a thickness of about 0.1 mm is used, and due to the ALD process characteristics, the metal diaphragm of the diaphragm valve for ALD is controlled to be opened and closed within 20 ms and the metal diaphragm is opened and closed more than 30 million times, therefore, the metal diaphragm valve is required to have the three characteristics of high-temperature resistance, fast response and long service life, the metal diaphragm is subjected to heat treatment to make it resistant to high temperature, however, the fast response and long service life are closely related to the linkage of the metal diaphragm and the actuator, because in use, the metal diaphragm is deformed by the piston rod to open and close the fluid passage or adjust the gas delivery of the fluid passage in the open state.

[0003] At present, the existing metal diaphragm valve on the market usually adopts a driving structure in which two pistons are connected with the piston rod in a limiting mode, the spring is pressed against the lower end flange of the piston rod, and the gas enters the corresponding gas cavities of the driving structure through two shunt gas channels on the piston rod to push the two pistons, and the two pistons and the piston rod are linked as a whole to make the piston rod overcome the elastic force of the spring and move, but the structure has the following shortcomings: because the elastic force of the spring is large, and the two pistons and the piston rod are metal parts and also have a large weight, once one of the shunt gas channels on the piston rod is blocked by foreign matters or lubricating grease, etc., the gas inlet efficiency of the gas cavity will be greatly reduced, the force applied by the gas cavity on one piston is not enough to push the piston to overcome the elastic force of the spring and the gravity of the two pistons and the piston rod, so that the piston rod cannot be separated from the diaphragm or the distance between the piston rod and the diaphragm is not enough, thereby causing the diaphragm to be unable to open the metal diaphragm valve or the opening of the metal diaphragm valve to be insufficient, and affecting the response speed and service life of the metal diaphragm valve. SUMMARY

[0004] The technical problem to be solved by the utility model is to provide a metal diaphragm valve to solve the problem that the piston rod gas channel part of the metal diaphragm valve is blocked, so that the piston rod cannot stably push the diaphragm to open and close the valve seat.

[0005] To solve the above technical problems, the utility model discloses the following technical scheme: a metal diaphragm valve, comprising: a valve body, having the inflow channel and the outflow channel for the fluid to pass through, a valve seat is located in the valve body, is used for the intercommunication of inflow channel and outflow channel, the diaphragm of metal can be elastically deformed, the diaphragm seal installation is located in the valve body and is located above the valve seat, still include actuator, the actuator includes with the valve body connection's casing, be located in the casing and axially extend's piston rod, and the first piston and the second piston of sliding sleeve are set on the piston rod, the first piston and the second piston are arranged at intervals in the axial direction of the piston rod, the first end of the first piston is elastically pressed with spring, the first piston and the second piston all with the casing inner wall sliding seal connection, wherein, the piston rod is used to push the diaphragm and close the valve seat;

[0006] The axial first side of the first piston forms the first installation cavity containing the spring, the axial second side of the first piston forms the first drive air cavity, the axial first side of the second piston forms the second installation cavity, the axial second side of the second piston forms the second drive air cavity, the piston rod is provided with an air passage, and a first shunt passage and a second shunt passage are in communication with the air passage;

[0007] The first shunt passage is in communication with the first drive air cavity, and the first piston can be driven to slide axially relative to the piston rod towards the spring to compress the spring by inflating the first drive air cavity, the outer wall of the piston rod has a protruding portion located on the axial second side of the first piston, the protruding portion abuts against the second end of the first piston, and the piston rod can drive the first piston to move axially by the protruding portion to compress the spring;

[0008] The second shunt passage is in communication with the second drive air cavity, and the second piston can drive the piston rod to move axially by inflating the second drive air cavity. The technical scheme has the following technical effects:

[0009] The metal diaphragm valve provided by the utility model, through setting the first piston to be slidable along the axial direction between the protruding part and the spring relative to the piston rod, the linkage of the first piston, the second piston and the piston rod can be realized by charging and discharging the air passage, even if the second shunt passage is blocked during the charging process, the gas in the air passage can enter the first driving air cavity through the first shunt passage to push the first piston to the spring direction, and then the first piston is away from the protruding part and the spring is pressed to the compressed state, at this time, the protruding part on the piston rod is no longer pushed by the first piston, and then the force applied by the piston rod on the diaphragm is smaller than the elastic force of the diaphragm, the diaphragm is reset to open the valve seat under the action of the elastic force, and the piston rod is pushed upward during the resetting process to reset the piston rod, and the inflow passage and the outflow passage are communicated. When the second piston cannot work due to the blockage of the second shunt passage by dust particles, lubricating grease and other foreign matters, the first piston can also move to the spring under the pushing of the gas to overcome the thrust applied by the spring on the piston rod, and then the elastic force of the diaphragm is enough to overcome the pressure applied by the piston rod on the diaphragm to open the valve seat, avoiding that the diaphragm cannot be opened or cannot be opened to the maximum due to the blockage of the second shunt passage, realizing the stable opening and closing of the diaphragm to the valve seat, and ensuring the response speed and service life of the metal diaphragm valve.

[0010] In the metal diaphragm valve, the fixed seat between the first piston and the second piston is fixed in the shell, the protruding part is arranged axially through the fixed seat and abuts against the second piston at the end away from the first piston, the protruding part and the fixed seat are sealed by the O-ring, and the inner walls of the first piston and the second piston are sealed and sleeved on the piston rod by the O-ring. By matching the protruding part with the fixed seat and arranging the O-ring between the protruding part and the fixed seat for sliding sealing, the gas in the first driving air cavity can be prevented from leaking to the second installation cavity through the gap between the piston rod and the fixed seat, the stable charging and discharging of the first driving air cavity are ensured, and then the stable pushing of the first driving air cavity to the first piston is ensured, so that the metal diaphragm valve can respond quickly to opening and closing.

[0011] In the metal diaphragm valve, the first piston is located above the second piston, the lower end of the spring abuts against the upper end of the first piston, the upper end of the spring abuts against the top wall of the shell, the first shunt passage is located above the second shunt passage, and the first shunt passage is arranged radially through the protruding part. The structure that the first shunt passage is arranged radially through the protruding part can shorten the length of the first shunt passage, so that the gas flows more smoothly in the first shunt passage, and the possibility of blockage caused by the accumulation of particulate matter or lubricating grease and the like in the first shunt passage is greatly reduced.

[0012] In the metal diaphragm valve, the shell has a first neck portion and a second neck portion, a spring is sleeved on the outer circumferential side of the first neck portion, the first piston compresses the spring and can abut against the first neck portion, the first neck portion and the second neck portion are in a cylindrical shape and are arranged oppositely in the up-down direction, the piston rod is in an integrated structure, the upper end of the piston rod is inserted into the first neck portion and the two are sealed by an O-shaped ring in sliding, and the lower end of the piston rod is inserted into the second neck portion and the two are sealed by an O-shaped ring in sliding. The first neck portion and the second neck portion limit the piston rod in the radial direction, so that the piston rod can only move in the axial direction, the operation is more stable, the upper end and the lower end of the piston rod are sealed by O-shaped rings with the first neck portion and the second neck portion in sliding, respectively, so as to avoid the gap between the piston rod and the first neck portion or the second neck portion from being communicated with the internal space of the shell, thereby avoiding the impurities such as dust particles from the outside from entering the shell through the gap between the piston rod and the first neck portion or the second neck portion, and ensuring the cleanliness inside the shell.

[0013] In the metal diaphragm valve, the end faces of the two pistons facing the corresponding drive air cavities are drive faces, one of the drive faces and the inner wall of the corresponding drive air cavity is provided with a support protrusion at the outer edge, and the other one abuts against the support protrusion when the diaphragm closes the valve seat, so as to form an air gap communicated with the corresponding shunt passage between the drive face and the inner wall of the corresponding drive air cavity. When the air is filled, the gas in the air passage can quickly enter the two drive air cavities through the two shunt passages and the air gap, so as to avoid the drive faces of the two pistons from being too tightly attached to the inner bottom wall of the corresponding drive air cavity, and the support protrusion at the outer edge will not interfere with the flow of the drive gas in the shunt passage, so as to ensure the rapid inflation and deflation of the first drive air cavity, and further ensure the stable opening and closing of the valve seat by the piston rod through the diaphragm, and improve the response speed of the metal diaphragm valve.

[0014] In the metal diaphragm valve, the fixed seat is provided with a through hole for penetrating the protruding portion, one of the outer side wall of the protruding portion and the inner side wall of the through hole is provided with an O-shaped ring, and the other one is provided with a nickel-plated coating. During the axial movement of the protruding portion, the O-shaped ring slides along the surface of the nickel-plated coating and always seals and abuts against the nickel-plated coating. Because the nickel-plated coating has extremely fine crystals, it covers the surface in contact with the O-shaped ring, so that the surface in contact with the O-shaped ring has good polishing performance and is smoother. At the same time, the sealing effect between the O-shaped ring and the nickel-plated coating is good, the wear of the O-shaped ring is reduced, the nickel-plated coating has high surface hardness, good wear resistance and corrosion resistance, the surface in contact with the O-shaped ring can be reduced by the wear of the O-shaped ring, the wear of the lubricating grease on the O-shaped ring is reduced, and the service life is prolonged.

[0015] In the metal diaphragm valve, the two pistons and the shell are sealed by O-rings, one of the outer side walls of the pistons and the inner side walls of the shell is provided with an O-ring, and the other is provided with a nickel-plated coating, and during the sliding of the piston, the O-ring slides along the surface of the nickel-plated coating and is always in sealing contact with the nickel-plated coating. Because the nickel-plated coating has high surface hardness, good wear resistance and corrosion resistance, the surface in contact with the O-ring is provided, which can reduce the mutual wear between the piston and the shell, so that the sliding of the piston is smoother, the O-ring has good sealing effect between the piston and the shell, and the wear of the O-ring is reduced, the wear of the lubricating grease on the O-ring is reduced, and the service life is prolonged.

[0016] In the metal diaphragm valve, the outer side walls of the two pistons or the inner side walls of the shell are provided with sealing grooves for embedding O-rings, and the inner surfaces of the sealing grooves are covered with a nickel-plated coating. The nickel-plated coating provided on the inner wall of the sealing groove makes the inner wall of the sealing groove smoother, and even if the O-ring is compressed and deformed to contact the inner wall of the sealing groove, there will be little friction, the wear of the O-ring is reduced, and the sealing between the O-ring and the sealing groove is enhanced.

[0017] In the metal diaphragm valve, the O-ring is coated with lubricating grease. By coating the O-ring with lubricating grease, the friction between the two structures of the sliding seal can be reduced through the O-ring, so that the movement of the piston rod is smoother, the stability of the diaphragm is ensured, and the wear of the O-ring during sliding is reduced.

[0018] In the metal diaphragm valve, the diaphragm is a metal diaphragm sealingly installed on the valve body, and the actuator includes a pressing piece clamped between the lower end of the piston rod and the metal diaphragm. The piston rod pushes the metal diaphragm to close the valve seat through the pressing piece, the pressing piece increases the pressure area of the metal diaphragm, so that the pushing effect of the piston rod on the metal diaphragm is better, the local pressure of the metal diaphragm is avoided to be too large to damage, and the service life of the metal diaphragm is prolonged.

[0019] The characteristics and advantages of the present application will be described in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] The present application will be further described below in conjunction with the drawings and specific embodiments:

[0021] Figure 1 It is a perspective view of the metal diaphragm valve in embodiment one;

[0022] Figure 2 It is a sectional view of the metal diaphragm valve in embodiment one in an open state;

[0023] Figure 3 It is a partial sectional view of the metal diaphragm valve in embodiment one in a closed state;

[0024] Figure 4 isometric view of the piston rod in embodiment one;

[0025] Figure 5 isometric view of the fixed seat in embodiment one.

[0026] Reference signs:

[0027] 100, valve body; 110, inflow passage; 120, outflow passage;

[0028] 200, valve seat;

[0029] 300, diaphragm;

[0030] 400, actuator; 410, housing; 411, first neck; 412, second neck; 413, third sealing groove; 414, third O-ring; 420, piston rod; 421, air passage; 422, first shunt passage; 423, second shunt passage; 424, protrusion; 430, first piston; 431, first driving air cavity; 432, first mounting cavity; 433, first sealing groove; 434, first O-ring; 440, second piston; 441, second driving air cavity; 442, second mounting cavity; 443, second sealing groove; 444, second O-ring; 450, fixed seat; 451, fourth sealing groove; 452, fourth O-ring; 453, through hole; 460, driving face; 461, support protrusion; 470, air gap; 480, pressing piece;

[0031] 500, spring. DETAILED DESCRIPTION

[0032] The technical solutions of the embodiments of the present application will be explained and described below in combination with the drawings of the embodiments of the present application. However, the following embodiments are only preferred embodiments of the present application, and are not all. Based on the embodiments in the embodiments, other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0033] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise" and the like are the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0034] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more, unless otherwise explicitly limited.

[0035] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the present application, unless otherwise explicitly specified and limited, the "first" feature is "on" or "under" the "second" feature, which can include direct contact between the first and second features, or it can include indirect contact between the first and second features through another feature between them. Moreover, the "first" feature "on", "above" and "above" the "second" feature includes the "first" feature above and obliquely above the "second" feature, or only indicates that the "first" feature is higher than the "second" feature in horizontal height. The "first" feature "below", "below" and "below" the "second" feature includes the "first" feature below and obliquely below the "second" feature, or only indicates that the "first" feature is lower than the "second" feature in horizontal height.

[0037] Embodiment one:

[0038] A metal diaphragm valve, such as Figures 1 to 5As shown, the valve includes a valve body 100, a ring-shaped valve seat 200, a diaphragm 300 and an actuator 400, the valve body 100 has an inflow passage 110 and an outflow passage 120 for gas to pass through, the valve seat 200 is arranged on the valve body 100 for connecting the inflow passage 110 and the outflow passage 120, the peripheral side of the metal diaphragm 300 is sealingly mounted on the valve body 100 and above the valve seat 200, the metal diaphragm 300 is elastically deformable, which can be elastically deformed to open or close the valve seat 200, wherein the metal diaphragm 300 is made of nickel-cobalt alloy or stainless steel to provide certain strength and elasticity, the valve seat 200 is ring-shaped and made of fluororesin material such as PFA or PTFE or PCTFE, and the metal diaphragm 300 deforms the fluororesin valve seat 200 to seal. When the diaphragm 300 opens the valve seat 200, the inflow passage 110 and the outflow passage 120 are connected through the valve seat 200, so that the fluid in the inflow passage 110 flows into the outflow passage 120 through the valve seat 200; when the diaphragm 300 closes the valve seat 200, the inflow passage 110 and the outflow passage 120 are blocked to prevent the connection between the inflow passage 110 and the outflow passage 120, although Figure 1 and 2 The inflow passage 110 and the outflow passage 120 are shown, but they can also be the outflow passage 110 and the inflow passage 120, and the drawings are only for illustration.

[0039] The actuator 400 includes a housing 410, a piston rod 420, a first piston 430 and a second piston 440, as shown in Figure 1 The housing 410 is connected above the valve body 100 in the axial direction, as shown in Figure 2 The piston rod 420 is arranged in the housing 410 and extends axially in the housing 410, the upper end of the piston rod 420 is slidingly connected to the housing 410, the lower end of the piston rod 420 extends into the valve body 100 above the diaphragm 300, the piston rod 420 can slide up and down in the housing 410 in the axial direction, and when the piston rod 420 moves downward, it pushes the diaphragm 300 to deform downward to close the valve seat 200 by the diaphragm 300, wherein the piston rod 420, the first piston 430 and the second piston 44 are all made of metal to press and firmly press the metal diaphragm 300 when moving, so that the metal diaphragm 300 deforms and they themselves are not easy to deform.

[0040] The first piston 430 and the second piston 440 are sleeved on the piston rod 420 and are arranged axially spaced apart, with the first piston 430 above the second piston 440, and the outer circumferential sides of the first piston 430 and the second piston 440 are respectively in sliding connection with the inner side wall of the housing 410, and the upper end (first end) of the first piston 430 is elastically abutted by the spring 500, with the upper and lower ends of the spring 500 respectively abutting against the inner wall of the housing 410 and the top surface of the first piston 430, so as to push the first piston 430 towards the diaphragm 300, so as to configure the metal diaphragm valve as a normally closed valve, and when the valve is not used, the diaphragm 300 is pressed and sealed on the valve seat 200 to block the inflow passage 110 and the outflow passage 120.

[0041] The housing 410 is provided with two cavities, the first piston 430 is located in the upper cavity, the first driving gas cavity 431 is formed on the side of the first piston 430 axially towards the diaphragm 300 (i.e. below the first piston 430, i.e. the second side of the first piston 430 in the axial direction), the first mounting cavity 432 is formed on the side of the first piston 430 axially away from the diaphragm 300 (i.e. above the first piston 430, i.e. the first side of the first piston 430 in the axial direction), the spring 500 is accommodated in the first mounting cavity 432, and the first piston 430 is separated between the first driving gas cavity 431 and the first mounting cavity 432; the second piston 440 is located in the lower cavity, the second driving gas cavity 441 is formed on the side of the second piston 440 axially towards the diaphragm 300 (i.e. below the second piston 440, i.e. the second side of the second piston 440 in the axial direction), the second mounting cavity 442 is formed on the side of the second piston 440 axially away from the diaphragm 300 (i.e. above the second piston 440, i.e. the first side of the second piston 440 in the axial direction), and the second piston 440 is separated between the second driving gas cavity 441 and the second mounting cavity 442, so that the above-mentioned first side is the upper side of the first piston 430 and the second piston 440, and the above-mentioned second side is the lower side of the first piston 430 and the second piston 440. In addition, it should be understood that when the first driving gas cavity 431 and the second driving gas cavity 441 are closed and the first piston 430 and the second piston 440 are driven by air to move upwards to squeeze the first mounting cavity 432 and the second mounting cavity 442 to reduce the space, the first mounting cavity 432 and the second mounting cavity 442 can be communicated with the atmosphere through the through hole to release pressure.

[0042] An air passage 421 extending axially along the piston rod 420 is provided on the piston rod 420. A first diversion channel 422 and a second diversion channel 423 are also provided. The first diversion channel 422 is located above the second diversion channel 423. The first diversion channel 422 connects the air passage 421 to the first driving air chamber 431, and the second diversion channel 423 connects the air passage 421 to the second driving air chamber 441. Figure 4 As shown, the outer wall of the middle part of the piston rod 420 protrudes radially outward to form a protrusion 424 with an outer diameter larger than other parts of the piston rod 420. The protrusion 424 is located between the first piston 430 and the second piston 440, and abuts against the lower end (second end) of the first piston 430. The first piston 430 is slidably connected to the piston rod 420, that is, the first piston 430 can slide axially between the protrusion 424 on the piston rod 420 and the spring 500. It is easy to understand that, taking Figure 3 as an example, the axial and radial directions mentioned in this article refer to the cylindrical piston rod 420, where the axial direction is the vertical direction in the figure, and the radial direction is the horizontal direction.

[0043] In use, the air passage 421 is inflated. Air can be simultaneously supplied to the first driving air chamber 431 and the second driving air chamber 441 through the first diversion channel 422 and the second diversion channel 423. The driving gas pressure in the first driving air chamber 431 and the second driving air chamber 441 is constant. When the upward force of the gas in the first driving air chamber 431 and the second driving air chamber 441 on the two pistons is greater than the elastic force of the spring 500, the weight of the two pistons and the weight of the piston rod, the gas pressure in the first driving air chamber 431 and the second driving air chamber 441 can simultaneously push the first piston 430 and the second piston 440 upward. The first piston 430 compresses the spring 500 to a compressed state, and the second piston 440 abuts against the bottom of the protrusion 424 to drive the piston rod 420 to move upward at the same time. This causes the diaphragm 300, which is no longer compressed by the piston rod 420, to reset under its own elastic force to open the valve seat 200, thereby realizing the connection between the inflow channel 110 and the outflow channel 120.

[0044] In the process of inflation, if the second shunt passage 423 is blocked, and the gas in the overpassing passage 421 cannot enter the second driving gas cavity 441, that is, the gas in the overpassing passage 421 can only enter the first driving gas cavity 431 through the first shunt passage 422, under the constant pressure of the inflation driving gas, only the upward force of the gas in the first driving gas cavity 431 on the first piston 430 cannot push the piston rod 420 upward, the downward surface area of the first piston 430 is constant, according to the physical principle F=PS, the pressure of the inflation driving gas continues to increase, when the pressure in the first driving gas cavity 431 reaches a certain value, the first piston 430 can be pushed upward, the first piston 430 moves upward along the axis of the piston rod 420 to move away from the protruding portion 424 and press the spring 500, so that the spring 500 is in a compressed state. In the process of upward movement of the first piston 430 alone, only the elastic force of the spring 500 and the weight of the first piston 430 are overcome, that is, the force of the gas with increased pressure on the first piston 430 is greater than the elastic force of the spring 500 and the weight of the first piston 430. Then, the protruding portion 424 of the piston rod 420 is no longer pushed downward by the first piston 430, that is, the piston rod 420 is no longer pressed downward by the elastic force of the spring 500. At this time, the force exerted by the piston rod 420 on the diaphragm 300 is less than the elastic force of the diaphragm 300 itself, and the diaphragm 300 resets under the action of its own elastic force to open the valve seat 200, and in the process of resetting, the piston rod 420 is pushed upward to reset the piston rod 420, so as to realize the communication between the inflow passage 110 and the outflow passage 120. In summary, compared with the prior art, because the weight of the second piston 440 and the piston rod 420 does not need to be overcome, the requirement for the amplitude of the increased driving gas pressure is reduced, the driving gas entering the overpassing passage 421 comes from the entire system, and it is often very difficult to increase the pressure a little, which will affect the work of other parts of the system.

[0045] When it is necessary to close the metal diaphragm valve, the overpassing passage 421 is deflated, so that the gas in the first driving gas cavity 431 and the second driving gas cavity 441 is discharged through the overpassing passage 421, and the spring 500 pushes the first piston 430 downward under the action of its own elastic force. The first piston 430 moves downward under the pushing of the spring 500, the downward moving first piston 430 drives the piston rod 420 to move downward by abutting against the top of the protruding portion 424, the protruding portion 424 drives the second piston 440 to move downward by abutting against the top of the second piston 440, so that the piston rod 420 pushes the diaphragm 300 to elastically deform downward and closes the valve seat 200.

[0046] The utility model discloses a first piston 430 is set to the structure that can slide along the axial direction between the protruding portion 424 and spring 500 relative to the piston rod 420, make through the gas passage 421 inflation and deflation can realize the linkage of first piston 430, second piston 440 and piston rod 420, even if the second shunt passage 423 is blocked in the inflation process, the gas in the gas passage 421 can enter the first drive gas cavity 431 through the first shunt passage 422, slightly increase gas pressure to push first piston 430 to spring 500 direction, and further make first piston 430 away from protruding portion 424 and extrude spring 500 to compression state, at this moment, the protruding portion 424 on piston rod 420 no longer is pushed by first piston 430, and further make the force that piston rod 420 exerts on diaphragm 300 is less than the elastic force of diaphragm 300, and diaphragm 300 resets under the action of the elastic force of itself to open valve seat 200, and push piston rod 420 upwards in the process of resetting to make piston rod 420 reset, realize the intercommunication of inflow channel 110 and outflow channel 120. That is, when the second piston 440 cannot work due to the second shunt passage 423 is blocked by dust particles or lubricating grease and other foreign matters, first piston 430 can also move to spring 500 under the push of gas to overcome the thrust that spring 500 exerts on piston rod 420, and further make the elastic force of diaphragm 300 enough to overcome the pressure that piston rod 420 exerts on diaphragm 300 to open valve seat 200, avoid the second shunt passage 423 is blocked and causes diaphragm 300 to open or diaphragm 300 to open to the maximum extent, realize the stable opening and closing of diaphragm 300 to valve seat 200, guarantee the response speed and service life of metal diaphragm valve opening and closing.

[0047] As Figure 2As shown, the fixed seat 450 is arranged in the shell 410, and is horizontally arranged between the first piston 430 and the second piston 440. The fixed seat 450 is detachably connected with the shell 410, and the peripheral side of the fixed seat 450 is sealingly connected with the inner wall of the shell 410, so as to separate the second installation cavity 442 from the first driving gas cavity 431. The fixed seat 450 is provided with a through hole 453, and the protruding portion 424 passes through the fixed seat 450 through the through hole 453. The top end of the protruding portion 424 extends into the first driving gas cavity 431 above the fixed seat 450, and the bottom end of the protruding portion 424 extends into the second installation cavity 442 below the fixed seat 450. The O-rings are sealingly connected between the piston rod 420 and the inner wall of the through hole 453 of the fixed seat 450, between the piston rod 420 and the shell 410, between the piston rod 420 and the first piston 430, between the piston rod 420 and the second piston 440, between the shell 410 and the first piston 430, between the shell 410 and the fixed seat 450, and between the shell 410 and the second piston 440. Preferably, the O-rings are coated with lubricating grease. By coating the O-rings with lubricating grease, the friction between the two structures of the sliding seal can be reduced through the O-rings, so that the movement of the piston rod 420 is smoother, the stable opening and closing of the diaphragm 300 is ensured, and the wear of the O-rings during sliding is reduced. It can be understood that the O-rings involved in the valve are numerous, and the lubricating grease for reducing friction coated on the O-rings and the nickel plating coating described below are all to prevent the wear of the O-rings themselves and the lubricating grease. The debris generated by the wear of the O-rings themselves and the lubricating grease will cause the second shunt passage 423 on the piston rod 420 to be blocked.

[0048] As shown in the drawings, Figure 3 The O-rings arranged between the inner circle of the first piston 430 and the outer peripheral side of the piston rod 420 and between the outer circle of the first piston 430 and the inner wall of the shell 410 for sealing are first O-rings 434. The first sealing grooves 433 for accommodating the first O-rings 434 are arranged on the inner circle of the first piston 430 and the outer circle of the first piston 430. Of course, it can be understood that the first sealing grooves 433 can be arranged on the first piston 430. In another embodiment, the first sealing grooves can also be arranged on the piston rod and the shell opposite to the first piston.

[0049] The O-rings arranged between the inner circle of the second piston 440 and the outer peripheral side of the piston rod 420 and between the outer circle of the second piston 440 and the inner wall of the shell 410 for sealing are second O-rings 444. The second sealing grooves 443 for accommodating the second O-rings 444 are arranged on the inner circle of the second piston 440 and the outer circle of the second piston 440. Of course, it can be understood that the second sealing grooves 443 can be arranged on the second piston 440. In another embodiment, the second sealing grooves can also be arranged on the piston rod and the shell opposite to the second piston.

[0050] The O-ring arranged between the piston rod 420 and the housing 410 is defined as the third O-ring 414, and the inner wall of the housing 410 is provided with a third sealing groove 413 for accommodating the third O-ring 414. Of course, it can be understood that in other embodiments, the third sealing groove can also be arranged on the piston rod.

[0051] The O-ring arranged between the fixed seat 450 and the piston rod 420 and arranged between the fixed seat 450 and the housing 410 for sealing is defined as the fourth O-ring 452, and the outer circle of the fixed seat 450 and the inner circle of the fixed seat 450 are both provided with a fourth sealing groove 451 for accommodating the fourth O-ring 452. Of course, it can be understood that the fourth sealing groove 451 can be arranged on the fixed seat 450, and in other embodiments, the fourth sealing groove can also be arranged on the piston rod and the housing opposite to the fixed seat. The embodiment of arranging the first O-ring 434, the second O-ring 444, the third O-ring 414 and the fourth O-ring 452 is the preferred embodiment of the present embodiment, and in other embodiments, one or more of the first O-ring, the second O-ring, the third O-ring and the fourth O-ring can be selected and arranged.

[0052] In the present embodiment, the first shunt passage 422 is arranged radially through the protruding portion 424, and the second shunt passage 423 is arranged radially through the piston rod 420. The structure of the first shunt passage 422 and the second shunt passage 423 radially through the piston rod 420 can shorten the length of the first shunt passage 422 and the second shunt passage 423, so that the gas flows more smoothly in the first shunt passage 422 and the second shunt passage 423, greatly reducing the possibility of particles or lubricating grease in the gas accumulating in the first shunt passage 422 and the second shunt passage 423 to cause blockage.

[0053] As Figure 2As shown, the housing 410 of the present embodiment has a first neck portion 411 and a second neck portion 412, the spring 500 is sleeved on the outer peripheral side of the first neck portion 411, and the first piston 430 compresses the spring 500 and can abut against the first neck portion 411. The first neck portion 411 and the second neck portion 412 are both cylindrical and oppositely arranged in the up-down direction. The first neck portion 411 is formed by extending inward from the top of the housing 410. The second neck portion 412 is formed by radially contracting inward from the lower part of the housing 410. The piston rod 420 of the present embodiment is of an integrated structure. The upper end of the piston rod 420 is inserted into the first neck portion 411, and the lower end of the piston rod 420 is inserted into the second neck portion 412, so that the piston rod 420 is in sliding connection with the first neck portion 411 and the second neck portion 412 respectively, thereby limiting the piston rod 420 in the radial direction and allowing the piston rod 420 to move only in the axial direction. The upper end and the lower end of the piston rod 420 are respectively sealed by the third O-ring 414 and the first neck portion 411 and the second neck portion 412, so as to avoid the gap between the piston rod 420 and the first neck portion 411 or the second neck portion 412 from being in communication with the internal space of the housing 410, thereby avoiding the impurities such as dust particles from the outside from entering the housing 410 through the gap between the piston rod 420 and the first neck portion 411 or the second neck portion 412, and ensuring the cleanliness inside the housing 410. In addition, the third O-ring 414 on the second neck portion 412 is close to the second shunt passage 423, and the impurities generated after the lubricating grease on the third O-ring 414 rubs against the piston rod 420 for a long time are most likely to block the second shunt passage 423. Therefore, the integrated structure of the piston rod 420 in combination with the linkage design of the above-mentioned protruding portion 424 makes the metal diaphragm valve respond quickly and operate more stably, and has a long service life.

[0054] In the present embodiment, the inner wall of the housing 410 for abutting against the first O-ring 434 is provided with a nickel plating coating, and the outer side wall of the piston rod 420 for abutting against the first O-ring 434 is also provided with a nickel plating coating. When the first piston 430 moves axially relative to the housing 410 or the piston rod 420, the first O-ring 434 slides along the surface of the nickel plating coating and always seals against the nickel plating coating. Preferably, the inner wall of the first sealing groove 433 is also provided with a nickel plating coating, so that the inner wall of the sealing groove is smoother, thereby enhancing the sealing between the first O-ring 434 and the first sealing groove 433.

[0055] Similarly, the inner wall of the second sealing groove 443 is provided with a nickel plating coating, the inner wall of the housing 410 used for abutting the second O-ring 444 is provided with a nickel plating coating, and the outer side wall of the piston rod 420 used for abutting the second O-ring 444 is provided with a nickel plating coating. When the second piston 440 moves axially relative to the housing 410 or the piston rod 420, the second O-ring 444 slides along the surface of the nickel plating coating and is always in sealing abutment with the nickel plating coating. The inner wall of the third sealing groove 413 is provided with a nickel plating coating, and the outer side wall of the piston rod 420 used for abutting the third O-ring 414 is provided with a nickel plating coating. When the piston rod 420 moves axially relative to the housing 410, the third O-ring 414 slides along the surface of the nickel plating coating and is always in sealing abutment with the nickel plating coating. The inner wall of the fourth sealing groove 451 in the through hole 453 of the fixed seat 450 is provided with a nickel plating coating, and the outer side wall of the protruding portion 424 used for abutting the fourth O-ring 452 is provided with a nickel plating coating. When the protruding portion 424 slides axially in the through hole 453, the fourth O-ring 452 in the fourth sealing groove 451 slides along the surface of the nickel plating coating and is always in sealing abutment with the nickel plating coating.

[0056] The nickel plating coating has the effect of covering the surfaces in contact with the O-ring, making the surfaces in contact with the O-ring have good polishing performance and be smoother, achieving good sealing effect between the O-ring and the surfaces in contact with the O-ring while reducing wear on the O-ring. The nickel plating coating has high surface hardness, good wear resistance and corrosion resistance, and can reduce the wear of the surfaces in contact with the O-ring by the O-ring, thereby preventing the wear of the lubricating grease on the O-ring, reducing the risk of blockage, and prolonging the service life.

[0057] In the embodiment, the end face of the piston towards the corresponding driving air cavity is defined as the driving face 460, i.e. the end face of the first piston 430 towards the first driving air cavity 431 is the driving face 460, and the end face of the second piston 440 towards the second driving air cavity 441 is the driving face 460. An annular support protrusion 461 is arranged on the inner side wall or the inner bottom wall of the first driving air cavity 431, and the support protrusion 461 is located at the outer edge of the first driving air cavity 431. When the diaphragm 300 closes the valve seat 200, the driving face 460 of the first piston 430 abuts against the top of the support protrusion 461, so as to form an air vent gap 470 between the first piston 430 and the inner bottom wall of the first driving air cavity 431, which is in communication with the first shunt passage 422. In this way, when the air is filled, the gas in the air passage 421 can quickly enter the first driving air cavity 431 through the first shunt passage 422 and the air vent gap 470, so as to avoid that the driving face 460 of the first piston 430 and the inner bottom wall of the first driving air cavity 431 are too tightly fitted to be separated, and further avoid that the first piston 430 cannot quickly overcome the elastic force of the spring 500 under the above influence, so as to ensure the rapid filling and discharging of the first driving air cavity 431, and further ensure the stable opening and closing of the piston rod 420 to the valve seat 200 through the diaphragm 300.

[0058] Similarly, an annular support protrusion 461 is arranged on the inner side wall or the inner bottom wall of the second driving air cavity 441, and the support protrusion 461 is located at the outer edge of the second driving air cavity 441. When the diaphragm 300 closes the valve seat 200, the driving face 460 of the second piston 440 abuts against the top of the support protrusion 461, so as to form an air vent gap 470 between the second piston 440 and the inner bottom wall of the second driving air cavity 441, which is in communication with the second shunt passage 423. In this way, the gas in the air passage 421 can quickly enter the second driving air cavity 441 through the second shunt passage 423 and the air vent gap 470, so as to avoid that the driving face 460 of the second piston 440 and the inner bottom wall of the second driving air cavity 441 are too tightly fitted to be separated, and further ensure the rapid filling and discharging of the first driving air cavity 431 and the second driving air cavity 441, so as to enhance the stable opening and closing effect of the piston rod 420 to the valve seat 200. Of course, it can be understood that in another embodiment, the support protrusion arranged on the inner side wall or the inner bottom wall of the first driving air cavity can also be arranged on the driving face of the first piston, and the support protrusion arranged on the inner side wall or the inner bottom wall of the second driving air cavity can also be arranged on the driving face of the second piston.

[0059] In the embodiment, the actuator 400 comprises a pressing piece 480 clamped between the end of the piston rod 420 and the metal diaphragm 300, which can be fixed on the piston rod 420 or arranged separately from the piston rod 420. The piston rod 420 pushes the metal diaphragm 300 to close the valve seat 200 through the pressing piece 480. The arrangement of the pressing piece 480 increases the pressing area of the metal diaphragm 300, so that the pushing effect of the piston rod 420 on the metal diaphragm 300 is better, the local force of the metal diaphragm 300 is prevented from being too large to damage the metal diaphragm 300, and the service life of the metal diaphragm 300 is prolonged.

[0060] Embodiment two:

[0061] The difference between the embodiment and the embodiment one is that in the embodiment, the first axially slidable piston is located below the second piston, the second piston is clamped on the piston rod, the piston rod limits the second piston in the axial direction, the piston rod is further provided with a radial outwardly protruding stop portion, the stop portion is located on the side of the first piston facing the diaphragm, the first piston can slide along the axial direction of the piston rod between the fixed seat and the stop portion, the spring is abutted between the top surface of the first piston and the bottom surface of the fixed seat, the spring drives the stop portion abutting the first piston to move downward, and in turn drives the piston rod to move downward to push the diaphragm to close the valve seat.

[0062] The above only describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solution falling within the idea of the present application belongs to the protection scope of the present application. It should be noted that for ordinary technical personnel in the technical field, some improvements and decorations without departing from the principle of the present application are also considered as the protection scope of the present application.

Claims

1. A metal diaphragm valve, comprising: a valve body having an inflow passage and an outflow passage for fluid to pass through; a valve seat arranged on the valve body for communicating the inflow passage and the outflow passage; a metal diaphragm elastically deformable, the diaphragm being sealingly mounted on the valve body and above the valve seat for opening and closing the valve seat; characterized in that an actuator is further included, the actuator comprising a housing connected with the valve body, a piston rod arranged in the housing and extending axially, and a first piston and a second piston slidingly sleeved on the piston rod, the first piston and the second piston being arranged in axial direction of the piston rod, a first end of the first piston being elastically pressed against a spring, the first piston and the second piston being in sliding sealing connection with the inner wall of the housing, wherein the piston rod is used to push the diaphragm to close the valve seat; an axial first side of the first piston forms a first mounting cavity accommodating the spring, an axial second side of the first piston forms a first driving air cavity, an axial first side of the second piston forms a second mounting cavity, and an axial second side of the second piston forms a second driving air cavity, the piston rod is provided with an air passage and a first shunt passage and a second shunt passage in communication with the air passage; the first shunt passage is in communication with the first driving air cavity, the first piston is driven to slide axially relative to the piston rod towards the spring to compress the spring by inflating the first driving air cavity, the outer wall of the piston rod is radially outwardly convex with a protrusion located at the axial second side of the first piston, the protrusion is in abutment with the second end of the first piston, and the piston rod can axially push the first piston to move axially to compress the spring through the protrusion; the second shunt passage is in communication with the second driving air cavity, and the second piston drives the piston rod to move axially together by inflating the second driving air cavity.

2. A metal diaphragm valve according to claim 1, characterized in that: a fixing seat is fixed in the housing between the first piston and the second piston, the protrusion is arranged axially through the fixing seat and in abutment with the second piston at an end away from the first piston, the protrusion and the fixing seat are in sliding sealing through an O-ring, and the inner walls of the first piston and the second piston are in sealing sleeve connection with the piston rod through O-rings.

3. A metal diaphragm valve according to claim 1, characterized in that: the first piston is located above the second piston, the lower end of the spring is in abutment with the upper end of the first piston, the upper end of the spring is in abutment with the top wall of the housing, the first shunt passage is located above the second shunt passage, and the first shunt passage is arranged radially through the protrusion.

4. A metal diaphragm valve as defined in claim 1, wherein: the housing has a first neck portion and a second neck portion, the spring is sleeved on the peripheral side of the first neck portion, the first piston can be in abutment with the first neck portion when the spring is compressed, the first neck portion and the second neck portion are in cylindrical shape and arranged oppositely in up-down direction, the piston rod is in integral structure, the upper end of the piston rod is inserted into the first neck portion and the two are in sliding sealing through an O-ring, and the lower end of the piston rod is inserted into the second neck portion and the two are in sliding sealing through an O-ring.

5. A metal diaphragm valve as defined in claim 1, wherein: The end face of each piston towards the corresponding driving air cavity is a driving face, and the driving face is provided with a support protrusion on one of the inner walls of the corresponding driving air cavity, and the other one of the inner walls of the corresponding driving air cavity is in abutment with the support protrusion when the diaphragm closes the valve seat, so as to form an air gap between the driving face and the inner wall of the corresponding driving air cavity, which is in communication with the corresponding shunt channel.

6. A metal diaphragm valve as defined in claim 2, wherein: The fixed seat is provided with a through hole for penetrating the protruding part, one of the outer side wall of the protruding part and the inner side wall of the through hole is provided with the O-ring, and the other one is provided with a nickel plating coating, and during the axial movement of the protruding part, the O-ring slides along the surface of the nickel plating coating and is in sealing abutment with the nickel plating coating at all times.

7. A metal diaphragm valve as defined in claim 1, wherein: The O-ring is provided on one of the outer side wall of the two pistons and the inner side wall of the shell, and the other one is provided with a nickel plating coating, and during the sliding of the piston, the O-ring slides along the surface of the nickel plating coating and is in sealing abutment with the nickel plating coating at all times.

8. A metal diaphragm valve according to claim 7, characterized in that: The outer side wall of the two pistons or the inner side wall of the shell is provided with a sealing groove for embedding the O-ring, and the inner surface of the sealing groove is covered with a nickel plating coating.

9. A metal diaphragm valve according to claim 2 or 4 or 6 or 7, characterized in that: The O-ring is coated with lubricating grease.

10. A metal diaphragm valve as defined in claim 1, wherein: The actuator comprises a pressing piece clamped between the lower end of the piston rod and the metal diaphragm.

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