Methods for replacing diaphragm valves and their seats

Abstract

This invention provides a method for replacing a diaphragm valve and its valve seat. The diaphragm valve can suppress valve seat crushing or deformation even when performing high-speed opening and closing operations at high temperatures, and can stably ensure a high Cv value without fluctuation when operating at high flow rates. The valve seat is easy to replace. The present invention is a diaphragm valve (1), characterized in that it comprises: an outer wall portion (20) for assembling a valve seat provided in a primary side opening (13) within a main body (2); a stepped portion (21) provided in the inner periphery of the outer wall portion (20); a seat ring (4) pressed and fixed to the stepped portion (21); a flange portion (32) provided in the seat ring (4); and a pressing groove (42) for assembling a valve seat formed between the seat ring (4) and the outer wall portion (20) with the flange portion (32) as the bottom. The valve seat (3) is pressed and fixed to the pressing groove (42) such that the upper part of the valve seat (3) is slightly protruding, with the extension portion (27) of the outer periphery of the upper part of the valve seat (3) covering the position near the top (23) of the outer wall portion (20) and the extension portion (28) of the inner periphery of the upper part of the valve seat (3) covering the position near the top (35) of the seat ring (4).

Description

Technical Field

[0001] This invention relates to diaphragm valves and methods for replacing valve seats, and particularly to diaphragm valves that can maintain extremely high durability and stable Cv values, such as those used in ALD (Atomic Layer Deposition) processes. Background Technology

[0002] In recent years, there has been an increasing trend in the introduction of gas supply equipment for semiconductor manufacturing, such as the ALD process, which involves opening and closing valves in a short period of time. In processes like ALD, various gases, such as precursors, inert gases, and oxidizing gases, are alternately supplied to the chamber at a stable flow rate through a high-temperature atmosphere (around 250°C) with extremely short cycles and high-speed switching. Inside the chamber, wafers are homogeneously / uniformly deposited with atomic layers at the nanoscale to form a thin film.

[0003] At this point, for diaphragm valves, in addition to ensuring sealing when the valve is closed, they also need to have the heat resistance to withstand high temperatures of around 250°C, the stability of the gas flow rate that can be correctly supplied in a short time, the high shut-off performance to avoid gas mixing and the high-speed operation to switch the gas supply in a short time, and the high durability to withstand multiple valve opening and closing cycles.

[0004] In the ALD process, in order to enable the diaphragm valve to open and close rapidly in a short time, the number of valve opening and closing actions is greatly increased. When closing the valve, the pressure applied from the metal diaphragm to the resin valve seat becomes greater. As a result, the temperature of the supplied raw gas is also at a high temperature of about 250°C, which makes the valve seat prone to crushing or deformation. When the valve seat is crushed or deformed, not only can the sealing performance not be maintained, but the Cv value also changes and cannot be stabilized.

[0005] In cases where the valve seat is crushed or deformed and cannot maintain a seal, the damaged valve seat needs to be quickly removed from the main body and replaced with a new one. Therefore, for diaphragm valves used in the ALD process, it is required that the valve seat is not easily crushed or deformed. In addition, if the valve seat is crushed or deformed, it should be easy to replace.

[0006] As a diaphragm valve that allows for easy replacement of the valve seat, Patent Document 1 proposes a diaphragm valve in which the valve seat is pressed into a valve seat recess located inside the main body when the valve seat is installed using a valve seat setting tool. When the valve seat is removed, a valve seat extraction tool with a male thread at the top is used to carve a female thread on the inner circumferential surface of the valve seat, and the valve seat with the thread engaged with the male thread is pulled upward.

[0007] In addition, in Patent Document 2, a diaphragm valve is proposed as follows: when installing the valve seat, a tool is used to press the valve seat with a metal sleeve inserted on its inner circumference into the valve seat mounting hole of the main body; when removing the valve seat, a manual tool such as a manual tap is engaged with the inner circumference of the valve seat to pull both the sleeve and the valve seat out of the main body.

[0008] Prior art literature

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Publication No. 2017-516039

[0011] Patent Document 2: Japanese Patent No. 5280208. Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] However, in the diaphragm valve of Patent Document 1, there are no supporting components on the inner circumference side of the valve seat. Therefore, especially when using a valve seat made of a soft material such as PFA at a high temperature of around 250°C, the valve seat is prone to deforming towards the inner circumference side when the valve is closed. Due to the deformation, the top of the valve seat becomes lower, and the durability of the diaphragm decreases.

[0014] Additionally, when removing the valve seat, a valve seat extraction tool is used to carve female threads on the inner circumference of the valve seat, which generates tiny chips that may contaminate the flow path inside the main body.

[0015] In the diaphragm valve of Patent Document 2, the upper end protrudes from the surface of the valve cavity and the end of the sleeve to form a valve seat, thus the durability of the valve seat is problematic.

[0016] In addition, the inner diameter of the sleeve is smaller than the inner diameter of the primary side opening of the main body, which narrows the flow path and thus causes a decrease in the valve's flow rate.

[0017] Therefore, the present invention was developed to solve the above-mentioned problems. Its purpose is to provide a diaphragm valve and a method for replacing the valve seat. The diaphragm valve can suppress the occurrence of valve seat crushing or deformation even when the valve is opened and closed at high speed under high temperature conditions, and can stably ensure a large flow rate. In addition, it can stably maintain a high Cv value without change. Furthermore, the valve seat is easy to replace.

[0018] Solution for solving the problem

[0019] To achieve the above objectives, the invention involved in technical solution 1 is a diaphragm valve, characterized in that it is a diaphragm valve having a diaphragm that opens and closes by contacting and separating from a valve seat disposed within a main body. It comprises a primary side opening disposed in a main body having an inlet and an outlet, an outer wall portion disposed in the primary side opening for assembling a valve seat, a stepped portion disposed on the inner periphery of the outer wall portion, a seat ring pressed and fixed to the stepped portion, a flange portion disposed on the seat ring, and a pressing groove for assembling a valve seat formed between the seat ring and the outer wall portion and with the flange portion as its bottom. The valve seat is pressed and fixed to the pressing groove such that the upper part of the valve seat slightly protrudes, with the extended portion of the upper periphery covering the outer wall portion near the top and the extended portion of the upper inner periphery covering the seat ring near the top. The top of the seat ring is lower than the height of the aforementioned outer wall portion, and the inner diameter of the seat ring is larger than the inner diameter of the primary side opening.

[0020] The invention involved in technical solution 2 is a diaphragm valve, wherein a female thread is provided on the inner circumferential surface of the seat ring.

[0021] The invention involved in technical solution 3 is a diaphragm valve, wherein a pressing step portion is further provided in the stepped portion, and a seat ring is pressed into the pressing step portion to press and fix the seat ring to the main body.

[0022] The invention involved in technical solution 4 is a diaphragm valve, wherein, regarding the bottom outer periphery of the valve seat, an expansion portion that increases the outer diameter in a manner that prevents it from falling off after being pressed in and fixed is engaged with an engagement portion provided on the outer wall portion, so that the valve seat will not fall off after being pressed in and fixed.

[0023] The invention involved in technical solution 5 is a method for replacing the valve seat of a diaphragm valve. In this method, when assembling the valve seat, the bottom of the valve seat is pressed into and fixed into the pressing groove while in contact with the upper surface of the flange. Then, when disassembling the valve seat, a clamp with a male thread is threaded into a female thread on the inner circumferential surface of the seat ring, and the clamp is lifted. The bottom of the valve seat is then locked by the flange of the seat ring, and the valve seat is pulled out at the same time.

[0024] The effects of the invention

[0025] According to the invention described in technical solution 1, a diaphragm valve can be obtained that can suppress valve seat crushing or deformation under high temperature conditions, and maintain a high flow rate (high Cv value) in a stable state with high durability and no change. Furthermore, even if a seat ring is provided, the flow path area of ​​the primary side opening will not be reduced, and the flow from the primary side opening to the valve chamber will not be obstructed, thus ensuring a large flow rate.

[0026] According to the invention involved in technical solution 2, the valve seat can be easily replaced without damage.

[0027] According to the invention involved in technical solution 3, the seat ring can be firmly pressed into and fixed to the main body, and the valve seat can be reliably fixed between the outer wall and the seat ring in a pressed-in state.

[0028] According to the invention involved in technical solution 4, the valve seat will not come out after being pressed and fixed, thus achieving high durability.

[0029] According to the invention involved in technical solution 5, the valve seat can be easily replaced. Attached Figure Description

[0030] Figure 1 This is a longitudinal cross-sectional view illustrating one embodiment of the diaphragm valve of the present invention.

[0031] Figure 2 yes Figure 1 A cross-sectional view of the main components of a diaphragm valve.

[0032] Figure 3 yes Figure 2 A partially enlarged cross-sectional view.

[0033] Figure 4 The accompanying drawings illustrate an example of a method for replacing a valve seat according to the present invention. (a) is a drawing illustrating a method for installing the valve seat, and (b) is a drawing illustrating a method for removing the valve seat. Detailed Implementation

[0034] Hereinafter, an example of an embodiment of the diaphragm valve of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a longitudinal cross-sectional view illustrating one embodiment of the diaphragm valve of the present invention. Figure 2 This is a cross-sectional view of the main parts of the diaphragm valve. Figure 3 This is a magnified cross-sectional view of the main part.

[0035] exist Figure 1 In the process, the diaphragm valve 1 consists of a body 2, a valve seat 3, a seat ring 4, a diaphragm 5, and an actuator 6.

[0036] The main body 2 is integrally formed of stainless steel material such as SUS316L, and is provided with an inlet 8 and an outlet 9. Inside it, a primary flow path 11 extending from the inlet 8 and a secondary flow path 12 extending from the outlet 9 are formed. The primary flow path is connected to the valve chamber 14 via a primary side opening 13, and the secondary flow path 12 is connected to the valve chamber 14 via a secondary side opening 15.

[0037] In addition, an opening 17 is provided on the upper part of the main body 2, and a female thread 18 is formed on the inner circumferential side of the opening 17, so that the male thread 19 formed at the lower end of the actuator 6 is threaded into the female thread 18, and the actuator 6 can be mounted on the upper part of the main body 2.

[0038] An outer wall portion 20 for assembling a valve seat is provided in the primary side opening 13, and a stepped portion 21 for pressing and fixing the seat ring 4 is provided on the inner circumference of the outer wall portion 20.

[0039] The top 23 of the outer wall portion 20 is formed in the shape of cross section R, and a recessed portion 24 in the shape of cross section R is formed on the lower inner circumferential side of the outer wall portion 20 for inserting the expanded diameter portion 30 of the valve seat 3.

[0040] In the step portion 21, there is a flange portion mounting step portion 25 for mounting the seat ring 4 and a pressing step portion 26 for pressing the seat ring 4 in. The bottom surface 25a of the flange portion mounting step portion 25 and the wall surface 26a of the pressing step portion 26 are connected by a gentle curved surface.

[0041] Valve seat 3 is made of resin material such as fluororesin and is arranged in a roughly cylindrical shape, such as... Figure 3 As shown in the figure, its cross-sectional shape is provided with an extension 27 of cross-sectional R shape with an increased upper outer periphery and an extension 28 of cross-sectional R shape with a decreased upper inner periphery. A gently curved surface connects the top 29 of the generally flat surface with the extension 27 and the extension 28. An expanded diameter section 30 of cross-sectional R shape with an increased outer diameter is provided at the bottom outer periphery.

[0042] In addition, such as Figure 2 As shown, the valve seat 3 is formed in such a way that when the valve seat 3 is pressed into and fixed to the press-in groove 42 for assembling the valve seat, the height of the valve seat 3 protruding above the top 23 of the outer wall portion 20 and above the top 35 of the seat ring 4 is as low as possible within the range that the lower surface 5a of the diaphragm 5 does not contact the top 23 of the outer wall portion 20 and the aforementioned top 35 of the seat ring 4 when the diaphragm 5 is closed.

[0043] In this example, the valve seat 3 is formed from PFA (perfluoroalkoxyethylene copolymer resin), but the material of the valve seat 3 is not limited to PFA, and the material can be changed appropriately. In addition, the flat shape connecting the top 29 of the valve seat 3 to the extensions 27 and 28 can be formed by machining or injection molding when forming the valve seat 3, or it can be formed by intentionally flattening it from the top using a jig or the like after assembling valve seats with different top shapes into the main body 2.

[0044] The seat ring 4 is made of stainless steel such as SUS316L and is generally cylindrical. It has a flange 32 on its outer circumferential surface that supports the bottom 31 of the valve seat 3, and a female thread 34 on its inner circumferential surface 33. The top 35 and the lower end 36 are formed in the shape of an R-section.

[0045] In addition, such as Figure 3As shown, the seat ring 4 is formed such that when the seat ring 4 is pressed and fixed to the pressing step portion 26, the top 35 of the seat ring 4 is ΔH lower than the top 23 of the outer wall portion 20. Furthermore, the inner diameter φD1 of the seat ring 4 is formed to be larger than the inner diameter φD2 of the primary side opening portion 13, and the outer diameter of the lower part of the seat ring 4 is set to be larger than the inner diameter of the wall surface 26a of the pressing step portion 26, thus enabling the seat ring 4 to be pressed into the pressing step portion 26.

[0046] In addition, in this example, the seat ring 4 is made of stainless steel (SUS316L), but the material of the seat ring 4 is not limited to stainless steel. It can also be made of plastic material as long as it is a material that can form a female thread 34 on the inner circumferential surface 33 and maintain its hardness appropriately at the operating temperature of the valve.

[0047] The diaphragm 5 is constructed by overlapping a predetermined number of thin metal plate-like components, so that in its natural state it presents a roughly disc-shaped appearance with a gently convex curved surface centered on the top and facing one side, and has an elastic force that allows it to self-restore to its natural state.

[0048] like Figure 2 As shown in the diagram, if the diaphragm 38 of the actuator 6 descends, the central area of ​​the diaphragm 5 is pressed and deformed around the central area, and the diaphragm 5 sits on the valve seat 3 and becomes a closed valve.

[0049] In addition, if there is no pressure from the diaphragm 38, the diaphragm 5 will push the diaphragm 38 upward by its elastic force and deform along the direction of restoring the convex surface. The diaphragm 5 will then leave the valve seat 3 and become open.

[0050] Actuator 6 is an air-driven actuator. If air is supplied from the air supply port 39 located at the top, piston 41 rises against the pressing force of spring 40, thus the pressing force of diaphragm 38 disappears, and the valve becomes open. If the air supply is stopped, piston 41 falls due to the elastic force of spring 40, generating the pressing force of diaphragm 38, and the valve becomes closed.

[0051] Next, the function of the diaphragm valve of the present invention in the above embodiments will be explained.

[0052] like Figure 3 As shown, if the seat ring 4 is pressed into the pressing step portion 26 provided on the main body 2, the lower part of the seat ring 4 can be reliably and firmly fixed to the pressing step portion 26 by setting the outer diameter of the lower part of the seat ring 4 to a diameter that can be pressed and fixed to the pressing step portion 26. The flange portion 32 is housed in the flange portion mounting step portion 25. Between the seat ring 4 and the outer wall portion 20, the upper surface 32a of the flange portion 32 forms a pressing groove 42 for mounting the valve seat.

[0053] At this time, the lower end 36 of the seat ring 4 is formed with a cross-section of R. In addition, a stepped portion 21 is formed by connecting the bottom surface 25a of the flange mounting step portion 25 and the wall surface 26a of the press-in stepped portion 26 using a curved surface, which makes it easy to press the seat ring 4 into the press-in stepped portion 26. Furthermore, the seat ring 4 is fixed to the press-in stepped portion 26 by an interference fit, so when removing the seat ring 4 from the press-in stepped portion 26, it is only necessary to pull the seat ring 4 upward.

[0054] If the valve seat 3 is pressed into the press-in groove 42 formed in this way, the valve seat 3 can be fixed to the main body 2. An enlarged diameter portion 30 with an R-shaped cross-section is provided on the outer periphery of the bottom of the valve seat 3, and the top 23 of the outer wall portion 20 is formed in the R-shaped cross-section, so the valve seat 3 can be easily pressed into the press-in groove 42. Furthermore, after being pressed into the press-in groove 42, the enlarged diameter portion 30 engages with the R-shaped recess 24 formed on the lower part of the inner periphery of the outer wall portion 20, preventing the valve seat 3 from coming out of the press-in groove 42.

[0055] If the valve seat 3 is assembled in the press-in groove 42, the valve seat 3 is fixed in a press-in state by the inner peripheral surface 43 of the outer wall portion 20 and the outer peripheral surface 44 of the seat ring 4. Therefore, the inner peripheral surface 43 of the outer wall portion 20 and the outer peripheral surface 45 of the valve seat 3 are reliably sealed, and thus no back leakage of the valve seat 3 will occur.

[0056] Furthermore, the valve seat 3 is fixed in a pressed-in state by the inner peripheral surface 43 of the outer wall portion 20 and the outer peripheral surface 44 of the seat ring 4. Therefore, even if the diaphragm valve 1 is in the closed state and the top 29 of the valve seat 3 is pressed by the diaphragm 5, the portion of the valve seat 3 supported from the inner and outer peripheries by the inner peripheral surface 43 of the outer wall portion 20 of the main body 2 and the outer peripheral surface 44 of the seat ring 4 will not tilt.

[0057] Furthermore, the top 29 of the valve seat 3 is formed as a generally flat surface, and an extension 27 with an increased outer periphery and an extension 28 with a decreased inner periphery and an R-shaped cross-section are provided on the upper part. A gently curved surface connects the top 29 with the extensions 27 and 28. Therefore, if the valve seat 3 is pressed into the pressing groove 42, then... Figure 3 As shown, the extension 27 is closed and covered near the top 23 of the outer wall portion 20, and the extension 28 is closed and covered near the top 35 of the seat ring 4. The top 29 of the valve seat 3 is supported from the outer peripheral side by the top 23 of the outer wall portion 20 and from the inner peripheral side by the top 35 of the seat ring 4.

[0058] As a result, the pressure-bearing area of ​​the top 29 of the valve seat 3 increases. When the diaphragm valve 1 is closed, the surface pressure of the top 29 of the valve seat 3 being pressed by the lower surface 5a of the diaphragm 5 decreases, thus suppressing the crushing of the valve seat 3.

[0059] In addition, such as Figure 2 and Figure 3 As shown, regarding the valve seat 3, when the valve seat 3 is assembled into the press-in groove 42 for assembling the valve seat, the height of the portion of the valve seat 3 that protrudes above the top 23 of the outer wall portion 20 and above the top 35 of the seat ring 4 is set as low as possible within the range where the lower surface 5a of the diaphragm 5 does not contact the top 23 of the outer wall portion 20 and the top 35 of the seat ring 4 when the diaphragm valve 1 is in the closed state. Therefore, the height of the portion of the valve seat 3 that protrudes above the top 23 of the outer wall portion 20 and above the top 35 of the seat ring 4 and is not supported from the inner and outer peripheries by the inner peripheral surface 43 of the outer wall portion 20 and the outer peripheral surface 44 of the seat ring 4 can be minimized.

[0060] As a result, the portion of the valve seat that is deformed by the lower surface 5a of the diaphragm 5 when the diaphragm valve 1 is in the closed state can be minimized, thereby suppressing the deformation of the valve seat 3.

[0061] Furthermore, the top 29 of the valve seat 3, which is impacted by the lower surface 5a of the diaphragm 5, is supported from the top 23 of the outer wall portion 20 via the extension 27, and from the top 35 of the seat ring 4 via the extension 28, from the inner and outer peripheries, thereby further suppressing the deformation of the valve seat 3 caused by the pressing of the diaphragm 5.

[0062] As described above, in the diaphragm valve of the present invention, when the valve is closed, the surface pressure of the valve seat 3 pressed by the lower surface 5a of the diaphragm 5 is reduced, suppressing valve seat crushing and greatly suppressing valve seat 3 deformation, thereby improving the durability of the valve seat 3. Furthermore, with the improved durability of the valve seat 3, the flow rate over time can be stabilized.

[0063] like Figure 3 As shown, the seat ring 4, pressed into the press-in step portion 26, forms a press-in groove 42 for assembling the valve seat between itself and the outer wall portion 20, with the flange portion 32 as its bottom. The bottom 31 of the valve seat 3 is supported by the flange portion 32. The inner diameter φD1 of the seat ring 4 is larger than the inner diameter φD2 of the primary side opening portion 13, so even if the seat ring 4 is positioned in the primary side opening portion 13, the flow path area of ​​the primary side opening portion 13 will not be reduced.

[0064] In addition, the top 35 of the seat ring 4 is formed in the shape of cross section R, and the height of the seat ring 4 is set such that the top 35 of the seat ring 4 is lower than the top 23 of the outer wall portion 20 by ΔH when the seat ring 4 is pressed and fixed to the pressed step portion 26, so as not to obstruct the flow from the primary side opening portion 13 toward the valve chamber 14.

[0065] As described above, even if the seat ring 4 is positioned in the primary side opening 13, the flow area of ​​the primary side opening 13 will not be reduced. In addition, the flow from the primary side opening 13 toward the valve chamber 14 will not be obstructed, thus ensuring a large flow rate and increasing the valve's Cv value.

[0066] Furthermore, a female thread 34 is formed on the inner circumferential surface 33 of the seat ring 4, so that the male thread of the clamp for loading and unloading the seat ring is threaded into the female thread 34, making it easy to load and unload the seat ring 4 from the body 2. In addition, the valve seat 3 supports the bottom 31 on the flange 32 and is pressed into the press-in groove 42, so that when the valve seat 3 is removed, if the seat ring 4 is pulled, the valve seat 3 is locked in the flange 32, so the valve seat 3 and the seat ring 4 can be removed at the same time, thus making it easy to remove the valve seat 3 and replace the valve seat 3 without damaging it.

[0067] Next, the method for replacing the valve seat of the present invention will be described. Figure 4 The accompanying drawings illustrate a method for replacing the valve seat of the diaphragm valve of the present invention, using an example of a clamp for loading and unloading the seat ring. The clamp for loading and unloading the seat ring differs during valve seat 3 assembly and disassembly; therefore, the assembly of valve seat 3 will be described first.

[0068] The clamp 47 for assembling the valve seat 3 consists of an adapter 48 and a pressing member 50. The adapter 48 is a part for pressing the pressing member 50 into the main body 2. It has an insertion through hole 51 in the center for inserting the pressing member 50 through, a male threaded portion 52 on the lower outer periphery that is threaded into the female threaded portion 18 of the main body 2, and a pressing surface 53 at the lower end for pressing the pressing member 50. The pressing member 50 is a part for pressing the seat ring 4 into the pressing step portion 26 of the main body 2. It has a flange portion 54 at the lower end that receives pressing pressure from the pressing surface 53 of the adapter 48, and a male threaded portion 55 at the lower top end for threadedly engaging the seat ring 4.

[0069] When using the clamp 47 to assemble the valve seat 3 into the main body 2, firstly, with the bottom 31 of the valve seat 3 in contact with the upper surface 32a of the flange portion 32, the valve seat 3 is installed on the seat ring 4, and the seat ring 4 is screwed into the male thread portion 55 at the lower top of the press-in member 50 until the top 29 of the valve seat 3 is connected to the lower surface 50a of the press-in member 50. Then, the press-in member 50 with the seat ring 4 threaded on the lower surface side of the adapter 48 is inserted into the through insertion hole 51.

[0070] Next, gently screw the male thread 52 of the adapter 48 into the female thread 18 provided on the inner circumference of the opening 17 of the main body 2, and install the adapter 48, with the pressing member 50 inserted through it, onto the upper part of the main body 2. In this state, the center of the opening 17 of the main body 2 is aligned with the center of the seat ring 4, so gently press the pressing member 50 in until the bottom 31 of the valve seat 3 contacts the top 23 of the outer wall 20. Then, gently screw the adapter 48 in until the pressing surface 53 of the adapter 48 abuts against the flange 54 of the pressing member 50.

[0071] After confirming that the pressing surface 53 of the adapter 48 abuts against the flange 54 of the pressing member 50, if the adapter 48 is screwed in forcefully, the flange 54 of the pressing member 50 is pressed by the pressing surface 53 of the adapter 48, and the pressing member 50 moves downward. As a result, the lower part of the seat ring 4, which is threaded into the male thread 55 provided at the lower top of the pressing member 50, is pressed into the pressing step 26, and the valve seat 3, whose top 29 is pressed by the lower surface 50a of the pressing member 50, is pressed into the pressing groove 42.

[0072] If the seat ring 4 is pressed into the step portion 26 and the valve seat 3 is pressed into the groove 42, the valve seat 3 is held in a tight contact between the inner circumferential surface 43 of the outer wall portion 20 and the outer circumferential surface 44 of the seat ring 4, and the assembly of the valve seat 3 into the body 2 is completed.

[0073] Next, the disassembly of valve seat 3 will be explained. The clamp 56 used to disassemble the seat ring consists of adapter 48, pressure-bearing metal part 57, spacer 58, locking bolt 59, and nut 60.

[0074] The adapter 48 is a part that can be used in conjunction with the clamp 47, but when used for removing the valve seat 3, the pressure-bearing metal part 57 is fitted into the mounting step portion 48a provided on the upper surface. The pressure-bearing metal part 57 is a part for transmitting the pressing pressure from the adapter 48 to the head 59a of the engaging bolt 59, and has a bolt insertion through hole 57a through which the engaging bolt 59 is inserted. The spacer 58 is a part for aligning and holding the center of the engaging bolt 59 with the center of the adapter 48, and is provided centered on the bolt insertion through hole 58a. The engaging bolt 59 is a part for threadedly engaging the female thread portion 34 provided on the inner circumferential surface 33 of the seat ring 4 to pull the seat ring 4 from the press-in step portion 26. The nut 60 is a part for holding the spacer 58 in the insertion through hole 51 of the adapter 48.

[0075] When using the clamp 56 to remove the valve seat 3 from the main body 2, firstly, after inserting the locking bolt 59 into the bolt insertion through hole 57a of the pressure-bearing metal part 57 and the bolt insertion through hole 58a of the spacer 58, the nut 60 is threaded onto the locking bolt 59 and screwed in until the gap between the lower surface of the spacer 58 and the upper surface of the nut 60 is about the thickness of the seat ring 4, so that the pressure-bearing metal part 57, the spacer 58, the locking bolt 59, and the nut 60 become a single unit.

[0076] Subsequently, the pressure-bearing metal part 57, spacer 58, locking bolt 59, and nut 60, which will become an integral unit, are inserted from above the adapter 48 into the insertion through hole 51. The pressure-bearing metal part 57 is assembled onto the mounting step portion 48a. The male thread portion 52 of the adapter 48 is screwed into the female thread portion 18 provided on the inner circumference of the opening portion 17 of the main body 2. The adapter 48 is then installed on the upper part of the main body 2. In this state, the center of the primary side opening portion 13 of the main body 2 coincides with the center of the locking bolt 59. Therefore, if the locking bolt 59 is screwed in, the locking bolt 59 is threadedly engaged with the female thread portion 34 provided on the inner circumferential surface 33 of the seat ring 4 of the press-in step portion 26, which is pressed and fixed into the main body 2.

[0077] After confirming that the head 59a of the locking bolt 59 abuts against the pressure-bearing metal part 57, if the adapter 48 is rotated in the direction of disassembly from the main body 2 (left turn), as the adapter 48 rises, the head 59a of the locking bolt 59 is lifted upward via the pressure-bearing metal part 57. Consequently, the seat ring 4, which is threaded into the locking bolt 59, is pulled out from the press-in step 26 within the main body 2. At this time, the valve seat 3 is supported by the flange 32 of the seat ring 4. Therefore, as the seat ring 4 is pulled out, the flange 32 locks the bottom 31 of the valve seat 3 and pulls it out simultaneously, thus allowing the valve seat 3 to be removed from the main body 2 together with the seat ring 4 without damage.

[0078] Thus, in the valve seat replacement method of the present invention, the valve seat can be easily replaced without damaging it.

[0079] As explained in detail above, the diaphragm valve of the present invention can suppress the crushing or deformation of the valve seat even when performing high-speed opening and closing operations at high temperatures, and can stably ensure a large flow rate. In addition, the valve seat replacement method according to the present invention allows for easy replacement of the valve seat without damage, and is therefore suitable for semiconductor manufacturing apparatus using ALD process.

[0080] Symbol Explanation

[0081] 1. Diaphragm valve

[0082] 2. Main Body

[0083] 3 Valve seat

[0084] 4 rings

[0085] 5. Diaphragm

[0086] 6 Actuators

[0087] 13. Primary side opening

[0088] 20. Outer wall section

[0089] 21 Steps

[0090] 23 Top of the outer wall

[0091] 26 Press into the step section

[0092] 27 Extension

[0093] 28 Extension

[0094] 32 Flange portion

[0095] Top of 35 seat rings

[0096] 42 Press into the groove.

Claims

1. A diaphragm valve, characterized in that, It is a diaphragm valve having a diaphragm that opens and closes by contacting and separating from a valve seat disposed within the main body. The valve includes a primary side opening disposed in the main body having an inlet and an outlet; an outer wall portion disposed in the primary side opening for assembling a valve seat; a stepped portion disposed on the inner periphery of the outer wall portion; a seat ring pressed and fixed to the stepped portion; a flange portion disposed on the seat ring; and a press-in groove for assembling a valve seat formed between the seat ring and the outer wall portion, with the flange portion as its bottom. The valve seat is pressed and fixed to the press-in groove in such a state that the extension of the upper periphery of the valve seat, which enlarges the upper part of the valve seat, covers a position near the top of the outer wall portion, and the extension of the upper inner periphery of the valve seat, which reduces the upper part of the valve seat, covers a position near the top of the seat ring, causing the upper part of the valve seat to protrude slightly. The seat ring is formed such that the top of the seat ring is lower than the height of the outer wall portion and the inner diameter of the seat ring is larger than the inner diameter of the primary side opening portion.

2. The diaphragm valve according to claim 1, wherein, The inner circumferential surface of the seat ring is provided with a female thread portion.

3. The diaphragm valve according to claim 1 or 2, wherein, A pressing-in step is further provided in the stepped portion, and the seat ring is pressed into the pressing-in step to fix the seat ring to the main body.

4. The diaphragm valve according to claim 1 or 2, wherein, Regarding the bottom outer periphery of the valve seat, an enlarged portion that increases the outer diameter so as not to fall off after being pressed in and fixed is engaged with a engaging portion provided on the outer wall portion, so that the valve seat will not fall off after being pressed in and fixed.

5. A method for replacing the valve seat of the diaphragm valve as described in claim 1, wherein, When assembling the valve seat, with the valve seat in contact with the upper surface of the flange, the bottom of the valve seat is pressed into and fixed to the pressing groove. Then, when disassembling the valve seat, the clamp with the male thread is threaded into the female thread on the inner circumferential surface of the seat ring, and the clamp is lifted up. The bottom of the valve seat is locked by the flange of the seat ring, and the valve seat is pulled out at the same time.

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