JP2020122533A - Diaphragm valve manufacturing method - Google Patents

Abstract

To provide a diaphragm valve manufacturing method capable of reducing an aging variation of a flow rate and an influence on durability.SOLUTION: A diaphragm valve comprises: a body which has a valve chamber with an opening on an upper face thereof and fluid inflow and fluid outflow passages, respectively open on a bottom face of the valve chamber, installed in the body; an annular seat arranged around an opening of the fluid inflow passage on the bottom face of the valve chamber; a diaphragm which seals the valve chamber and opens and closes the fluid inflow passage with the same elastically deformed to come in contact with or move away from the seat; and a diaphragm operation section which has a tip section pressing the diaphragm so that the same is elastically deformed to come in contact with or move away from the seat. A manufacturing method for the diaphragm valve comprises: a step d1 to adjust an uplift amount of the tip section of the diaphragm operation section to a prescribed amount when moving away upon pressing and a step d2 to break in the diaphragm to come into contact with and move away from the seat predetermined times by the diaphragm operation section.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method of manufacturing a diaphragm valve.

A direct diaphragm valve (hereinafter, also simply referred to as “diaphragm valve”) is used for ON/OFF control of a process gas for semiconductor manufacturing (for example, Patent Document 1).
The diaphragm valve presses the diaphragm by an opening/closing mechanism that uses an air cylinder to separate/contact between the diaphragm and the valve seat to open/close the fluid flow path and control the flow/stop of the fluid. It is a valve that does. The diaphragm valve has an advantage that the controlled fluid is completely isolated from the opening/closing operation mechanism by the diaphragm, so that there is little occurrence of leakage or contamination.
As this valve seat (hereinafter referred to as “seat”), a resin material such as PTFE having appropriate flexibility and having high sealing property in a closed state is used.
A sheet made of such a resin material is gradually crushed when it comes into contact with the diaphragm many times by opening and closing after the start of use, and as a result, the gap between the sheet and the diaphragm in the open state gradually increases to facilitate the flow. There was a problem that the Cv value, which is an index of the size, becomes large. To deal with this problem, aging (run-in operation) is performed to open and close the diaphragm valve many times during manufacturing adjustment of the diaphragm valve to finish the change in seat shape due to opening and closing, and then set the gap between the seat and diaphragm to a specified value. There is also proposed a method of adjusting so that such a change does not occur after delivery to the customer (Patent Document 2).

As such an aging method, Patent Document 2 describes opening and closing a predetermined number of times at a predetermined temperature (for example, 200° C.). Specifically, in the case of a diaphragm with an outer diameter of 26 mm, opening and closing aging is performed 3000 to 10,000 times with a full stroke (for example, lift amount ΔS is 1.2 mm), and then the lift amount is 55 to 70% of the full stroke (for example, 0.7%). mm) is used. As a result, the change in shape of the resin valve seat during actual use is reduced, the Cv value, which is an index of flowability, is stable, and since it is used with a short stroke during actual use, it is possible to ensure durability. Has been done.

Patent No. 6336345 Patent No. 5331180

However, the method of Patent Document 2 has the following problems.
Firstly, in this method, opening and closing aging is performed with the full stroke of which the lift amount is not adjusted, but when the lift amount is not adjusted, the lift amount is, for example, in the range of 1.1 mm to 1.3 mm due to the individual difference of the valve. Vary. If the opening and closing aging is performed in this state, the impact force applied to the seat by the opening and closing operation varies between the diaphragm valves, the effect of the opening and closing aging also varies, and as a result, the durability and the flow rate characteristic vary from product to product. Such variations are not desirable in recent years when there is an increasing demand for reducing machine differences.
Secondly, in the method of Patent Document 2, since opening and closing aging is performed with a large lift amount such as 1.2 mm before adjustment, the strain amount ε (outer diameter D, thickness t, lift amount) of the diaphragm during opening and closing aging. Is ΔS, the strain amount ε is considered to be proportional to tΔS/D), and there is a concern that opening and closing aging affects the durability of the diaphragm.

An object of the present invention is to solve the above problems, and to provide a method for manufacturing a diaphragm valve that can reduce the change over time in the flow rate and the variation between products, and can reduce the influence on the durability of the product.

The diaphragm valve manufacturing method of the present invention,
A body having a valve chamber having an opening on the upper surface and having a fluid inflow passage and a fluid outflow passage respectively open at the bottom surface of the valve chamber,
An annular seat disposed around the opening of the fluid inflow passage on the bottom surface of the valve chamber,
A diaphragm that is arranged so as to seal the valve chamber and that closes and opens the fluid inflow passage by elastically deforming and abutting and separating from the seat,
A diaphragm operating portion, the tip end portion of which moves up and down while pressing the diaphragm to bring the diaphragm into contact with and away from the seat,
A method of manufacturing a diaphragm valve comprising:
A step of adjusting a rising amount of the tip end portion of the diaphragm operating portion to a predetermined amount when the diaphragm is separated from the sheet when the sheet is pressed;
Thereafter, a step of performing a running-in operation of bringing the diaphragm into contact with and separating from the seat a predetermined number of times by the diaphragm operation unit is included.

Suitably, a configuration may be adopted in which the step of performing the break-in operation is performed at any temperature within a temperature range of 80°C to 150°C.

Suitably, the structure which is the upper limit temperature of the operating temperature range of the diaphragm valve can be adopted.

Preferably, the diaphragm is a circular laminated body having an outer diameter of 14.5 mm to 26.5 mm and made of a laminated body of a stainless steel thin plate and a nickel-cobalt alloy thin plate, and the predetermined number of times is at least 10,000 times. Can be adopted.

Preferably, the elastic deformation stroke can be configured such that the predetermined amount is 0.3 mm to 0.4 mm.

Suitably, the structure which further has the step of adjusting the Cv value of a diaphragm valve can be employ|adopted after the step which performs said break-in operation.

According to the present invention, the amount of lift (hereinafter referred to as "lift amount") of the diaphragm operation portion tip end when the diaphragm is pressed against the seat is separated from the seat, and then the opening/closing operation is performed a predetermined number of times (hereinafter referred to as "open/close aging"). Because the lift amount does not vary among the individual valves during opening and closing aging, it is possible to reduce variations in durability and flow rate among individual valves due to variations in the effect of opening and closing aging. ..
Moreover, since the opening and closing aging is performed with a small lift amount (for example, the lift amount at the time of product shipment 0.3 mm), the adverse effect on the durability of the diaphragm can be small. As a result of experience, if the lift amount is 0.3 mm, the durability of the diaphragm is 40 million times of opening/closing in actual value, so it is considered that there is no problem even if opening/closing aging is performed 10,000 times.

The schematic sectional drawing which shows the diaphragm valve of embodiment of this invention. FIG. 2 is an enlarged cross-sectional view when the diaphragm has a natural shape in FIG. 1. FIG. 2 is an enlarged cross-sectional view showing a state in which the diaphragm is in contact with the seat in FIG. 1. FIG. 2 is an enlarged cross-sectional view showing a state in which the diaphragm is separated from the seat in FIG. 1. 6 is a flowchart showing a manufacturing method according to the embodiment of the present invention. Explanatory drawing which shows the opening/closing aging method. Explanatory drawing which shows a Cv value measuring method. The graph which shows Cv value change by opening/closing aging. The graph which shows the Cv value change by 120 °C opening. Explanatory drawing about the factor of the shape change of a sheet.

(Diaphragm valve of the embodiment of the present invention)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the same NC (normally closed) type direct diaphragm valve as that of Patent Document 2 will be described as an example. FIG. 1 is a schematic cross-sectional view of this direct diaphragm valve. 2 is an enlarged cross-sectional view in which the diaphragm has a natural shape in FIG. 1, FIG. 3 is an enlarged cross-sectional view showing a state in which the diaphragm is in contact with the seat in FIG. 1, and FIG. 4 is a diaphragm in FIG. FIG. 6 is an enlarged cross-sectional view showing a state in which is separated from the sheet.

In FIG. 1, 1 is a body, 2 is a diaphragm, 3 is a presser adapter, 4 is a bonnet, 5 is a screw part, 6 is a spring, 7 is a diaphragm presser, 8 is a stem, 9 is an actuator, 10 is a fluid inlet, 11 is A fluid outlet, 12 a valve chamber, 13 a seat, 14 a drive shaft, 15 a stroke adjusting mechanism, 16 an electromagnetic valve, and 17 a proximity switch.

The body 1 is made of stainless steel in a substantially cross shape, and has a fluid inlet 10 and a fluid outlet 11 on both sides, and a concave valve chamber 12 that communicates with the fluid inlet 10 and the fluid outlet 11 and has an open upper portion. Has been formed. A seat 13 made of synthetic resin (PFA, PA, PI, PCTFE, etc.) is fitted and fixed to the bottom surface of the valve chamber 12. In this embodiment, the seat 13 is fixed in the valve insertion groove by so-called caulking.

The diaphragm 2 is disposed above the seat 13, maintains the airtightness of the valve chamber 12, and moves up and down with respect to the seat 13 by vertically moving the central portion thereof. In this embodiment, the diaphragm 2 has a circular shape by bulging the central portion of a metal thin plate (thickness 0.15 mm) such as special stainless steel or the like and a nickel-cobalt alloy thin plate (thickness 0.15 mm) upward. It is formed in a reverse dish shape, and three reverse stainless steel thin plates and a nickel-cobalt alloy thin plate are laminated in close contact with each other to form a reverse dish shape. Further, this diaphragm 2 has its peripheral edge portion placed on the protrusion of the inner peripheral surface of the valve chamber 12, and the lower end portion of the bonnet 4 inserted into the valve chamber 12 is screwed into the threaded portion 5 of the body 1. It is pressed against the protruding side of the body 1 via the stainless steel pressing adapter 3 and is sandwiched and fixed in an airtight state. The nickel-cobalt alloy thin film is arranged on the gas contact side.

In this embodiment, the diaphragm 2 has an outer diameter of 26 mm for a valve having a fluid passage inner diameter of 6.35 mmφ and a bulging portion having a radius of curvature of 60 mm. In addition to this, there are a diaphragm having a fluid passage inner diameter of 6.35 mmφ for an outer diameter of 20 mm and a radius of curvature of 62.6 mm, and a small valve of 6.35 mmφ for an outer diameter of 15 mm and a radius of curvature of 62.6 mm. Exists.

The bonnet 4 is formed in a tubular shape and is fixed to the body 1 side by being inserted into the valve chamber 12 of the body 1 and tightened by a screw portion 5 provided on the inner peripheral surface of the valve chamber 12. Has been done.

The stem 8 is inserted into the lower end portion of the bonnet 4 so as to be able to move up and down, and a synthetic resin diaphragm retainer 7 abutting against the upper surface of the central portion of the diaphragm 2 is fitted to the lower end surface.

More specifically, the stem 8 has a diaphragm retainer 7 made of polyimide attached to the lower end surface, which is vertically movable within the bonnet 4 so that the diaphragm retainer 7 contacts the diaphragm 2, and the elastic force of the spring 6 allows the diaphragm retainer to be pressed. It is pressed downward via 7 and the central portion of the diaphragm 2 is seated against the seat 13. A drive shaft 14 of an actuator 9 for operating the stem is fixed to the upper end of the stem 8.

A collar portion 8a is provided below the stem 8, and when the valve is fully closed (when the central portion of the diaphragm 2 is seated against the seat 13), the collar portion 8a is held by the pressing adapter 3. By contacting the upper surface of the stem 8, the excessive lowering of the stem 8 is restricted.

The stroke adjusting mechanism 15 is composed of a lock nut 15a or the like screwed to the supporting cylinder portion 9a of the actuator 9 screwed and fixed to the upper surface of the bonnet 4, and the screwing height of the supporting cylinder portion 9a into the bonnet 4. The lift amount ΔS is adjusted by adjusting the height position.

The electromagnetic valve 16 is directly fixed to the upper surface of the actuator 9 and controls the flow of the driving fluid (air) A supplied into the actuator 9. The actuator 9 is directly attached to the solenoid valve 16 in order to reduce the space of the drive fluid passage to enhance the responsiveness of the valve opening/closing operation as described later (shortening the opening/closing operation time). ..

The proximity switch 17 is for detecting the change state of the lift amount ΔS during valve opening/closing operation and the lift amount ΔS itself, and is fixed on the upper surface side of the actuator 9 and has a gap ΔG with the piston 9c. The lift amount ΔS is detected by measuring

Next, the operation of the diaphragm valve of this embodiment will be described. The valve shown in FIG. 1 is configured as an NC (normally closed) type, and the elasticity of the spring 6 normally presses the diaphragm 2 downward through the stem 8, and the lower surface (gas contact surface) of nickel The cobalt alloy thin plate is in contact with the sheet 13. The pressing force of the stem 8 is adjusted by the spring 6, and the descending amount of the stem 8 is restricted by the pressing adapter 3.

When the drive fluid A is supplied to the actuator 9, the drive shaft 14 is pulled upward by the lift amount ΔS via the piston 9c. As a result, the diaphragm 2 is restored to its original shape in which the central portion bulges upward due to its elastic force, and the valve is opened. The lift amount ΔS is adjusted to a predetermined value by the lock nut 15a of the stroke adjusting mechanism 15.

(Manufacturing Method of Embodiment of the Present Invention)
Next, the manufacturing method of the present invention for such a diaphragm valve will be described.
In the manufacturing method of the present embodiment, as a running-in (aging) method, the amount of rise (hereinafter referred to as "lift amount") of the tip of the diaphragm operation portion is adjusted when the diaphragm is separated from the sheet when pressed. After that, the method includes a step of performing opening and closing operations a predetermined number of times (hereinafter referred to as “opening and closing aging”) and further performing flow rate lift adjustment. FIG. 5 shows a flowchart of this embodiment.
The manufacturing method of the present embodiment,
(A) Parts manufacturing process,
(B) Parts cleaning and baking process,
(C) valve assembly process,
(D) Aging (run-in operation),
(E) Inspection process (He leak inspection, pressure inspection, cleanliness inspection, etc.),
including.
The production method of the present invention is characterized by the (d) aging (break-in) method, and the other steps (a), (b), (c), and (e) are the same as the conventional methods, and therefore, these Detailed description of the steps is omitted.
The (d) aging step of the present embodiment includes (d1) lift amount adjustment, (d2) opening/closing aging, and (d3) flow rate lift adjustment (Cv value adjustment).

(D1) Lift amount adjustment This step is a process of adjusting the amount of lift (that is, "lift amount") of the tip of the diaphragm operating portion when the diaphragm is pressed against the sheet and separated.
The purpose of this step is to ensure that the seat aging effect due to opening and closing becomes constant between valves in opening and closing aging (d2) described later, and that the load on the diaphragm due to opening and closing aging becomes excessive, leading to valve life. It is not to have an influence.
The lift amount set value is a predetermined value of 0.3 to 0.4 mm.

The reason for this is that with opening and closing aging, the larger the lift amount, the greater the impact force at the time of closing, so the aging effect is also considered to be large, but in the Cv value stability evaluation described below, opening and closing aging with a lift amount of 0.3 mm This is because a sufficient stabilizing effect is obtained.
As will be described later, the strain amount ε of the diaphragm during opening and closing aging (when the outer diameter is D, the thickness is t, and the lift amount is ΔS, the strain amount ε is considered to be proportional to tΔS/D) When the lift amount ΔS is 0.3 to 0.4 mm, the strain amount ε is smaller than that in the opening/closing aging of Patent Document 2 in any of the diaphragm outer diameters of 26 mm, 20 mm, and 15 mm. In addition, from experience, if the actual lift amount is 0.3 mm, the durability of the diaphragm has an opening and closing number of 40 million times in actual value, and it is considered that the influence of the opening and closing aging on the durability is small.

A specific method is, for example, turning on/off the operating air while measuring the height direction position of the piston 9c by the proximity switch 17 of the diaphragm valve shown in FIG. This is the lift amount. By rotating the actuator 9 screwed into the hood 4 and adjusting the vertical position of the actuator 9 so that the lift amount becomes, for example, 0.3 mm, the actuator 9 and the drive shaft 14 and the stem 8 are interposed. The upper limit position of the diaphragm retainer 7 connected by adjusting the upper limit is adjusted. After the adjustment, the lock nut 15a screwed onto the outer peripheral thread portion of the supporting cylinder portion 9a of the actuator 9 is tightened and fixed.

「リフト量」は前記理由で0.3mm〜0.4mmの所定の値に設定するが、本実施形態では0.3mmに設定した。
「閉動作の押付け力」は、本実施形態ではノーマルクローズ型のダイヤフラムバルブを使用するので、スプリング６の押付け力が閉動作の押付け力になる。
「開閉環境温度」は、120℃に限らず、80℃〜150℃の所定の温度を選択できる。但し、製品の使用可能温度範囲でなるべく高い温度に設定することが、エージング効果を促進できるので好ましい。なお、シートを構成するPTFE、PFA等の樹脂の最高使用温度は260℃程度とされており、上記温度範囲で開閉エージングを行うことは問題ない。
「開閉回数」を１万回としたのは、後述する開閉エージングによるＣｖ値変化の評価結果から、１万回の開閉でＣｖ値が安定し、かつ、120℃での開放置によるＣｖ値変化でも、好結果が得られたからである。なお、上記のように、経験上実使用リフト量0.3mmであれば、ダイヤフラムの耐久性は実力値で4000万回の開閉回数あるので、必要に応じて30万回程度まで開閉エージングを行うことは可能である。 (D2) Opening and closing aging Opening and closing aging is a process in which the valve is opened and closed a number of times under high temperature conditions and the seat is shocked and pressed a number of times by the diaphragm.
The purpose of this step is to complete the change with time of the seat by this opening and closing aging so that such change does not occur after delivery to the customer.
The opening/closing aging is performed under the conditions shown in Table 1, for example.

Although the "lift amount" is set to a predetermined value of 0.3 mm to 0.4 mm for the above reason, it is set to 0.3 mm in this embodiment.
Since the normally-closed diaphragm valve is used in this embodiment, the pressing force of the spring 6 becomes the pressing force of the closing operation.
The "opening and closing environment temperature" is not limited to 120°C, and a predetermined temperature of 80°C to 150°C can be selected. However, it is preferable to set the temperature as high as possible in the usable temperature range of the product because the aging effect can be promoted. The maximum operating temperature of the resin such as PTFE and PFA forming the sheet is set to about 260°C, and there is no problem in performing opening/closing aging within the above temperature range.
The "number of times of opening and closing" is set to 10,000 times because the Cv value is stable after 10,000 times of opening and closing and the Cv value changes due to opening at 120°C, based on the evaluation result of the change in Cv value due to opening and closing aging described later. However, the good result was obtained. As mentioned above, if the actual lift amount is 0.3 mm, the durability of the diaphragm is 40 million times of opening and closing in actual value, so open and close aging up to 300,000 times as necessary. Is possible.

FIG. 6 is an explanatory diagram showing the opening/closing aging method.
In the test device shown in FIG. 6, diaphragm valves configured as three air-operated valves can be opened and closed aged in parallel. Each diaphragm valve is placed in a thermostatic chamber set at a temperature of 120° C., the primary side is opened to atmospheric pressure, and the secondary side is evacuated by a vacuum pump.
The solenoid valve 16 (see FIG. 1) of each diaphragm valve (air operated valve) is supplied with nitrogen gas (0.5 MPa) as operating air from the operation unit, and a signal for turning the solenoid valve ON/OFF is also supplied. Sourced from.
Thereby, opening and closing is performed a predetermined number of times at a predetermined opening and closing speed.

式（１）においてQg〔m³/h（標準状態）〕は標準状態（15℃、760mmHgabs）に於ける気体の流量、t〔℃〕はガスの温度、Ggはガスの比重（空気＝1とした時の）、P₁〔MPa abs〕は一次側絶対圧力、P₂〔MPa abs〕二次側絶対圧力である。 (D3) Flow rate lift adjustment (Cv value adjustment)
In this step, after aging, the lift amount is adjusted again so that the Cv value, which represents the ease of flow of the controlled fluid when the valve is fully opened, becomes a predetermined value.
Although it is not an essential step in the present invention, it is a step for confirming whether a predetermined flow rate can be obtained when fully opened under a high temperature condition (for example, 120° C.) in which the sheet is easily expanded and the flow path is squeezed. Is preferred. For this purpose, it is preferable to set the temperature in this step to a temperature as high as possible within the usable temperature range of the product.
In the lift amount adjusting method of this step, as in the case of (d1), the actuator 9 screwed to the bonnet 4 is rotated to adjust the vertical position of the actuator 9.
When the fluid is a gas body, the Cv value is calculated by the following equation (1).

In the formula (1), Qg [m ³ /h (standard state)] is the gas flow rate in the standard state (15°C, 760 mmHgabs), t [°C] is the gas temperature, and Gg is the specific gravity of the gas (air = 1 , P ₁ [MPa abs] is the primary absolute pressure, and P ₂ [MPa abs] is the secondary absolute pressure.

FIG. 7 is an explanatory diagram showing a Cv value measuring method. Using the Cv value measurement test device shown in FIG. 7, the mass flow controller MFC measures the mass flow rate Qg of the nitrogen gas N2 supplied from the N2 (nitrogen gas) supply source, and the nitrogen gas N2 is cooled to a predetermined temperature ( It is heated to 120° C., passed through a diaphragm valve (open state with a predetermined lift amount) of a test product, and opened to the atmosphere via a dry pump DP. The pressures on the primary side and the secondary side of the diaphragm valve at this time are measured by pressure gauges P and P, respectively. The Cv value is calculated by the above equation (1) using the measurement result.

その結果、図８のグラフに示すように、各バルブとも、初期設定Cv値0.117からCv値が約15％上昇し、１万回の開閉エージングにより、Cv値の変化が安定することが分かる。 (Effects of the embodiment of the present invention)
FIG. 8 is a graph showing changes in Cv value due to opening and closing aging.
In this evaluation, three test valves were used, and opening/closing aging was performed with a lift amount of 0.3 mm. Each valve was taken out from the opening and closing aging device shown in FIG. 6 on a trial basis every 10,000 opening and closing times, and the Cv value was measured by the Cv measurement test device shown in FIG. 7.
Table 2 shows the test conditions.

As a result, as shown in the graph of FIG. 8, it can be seen that, for each valve, the Cv value increases from the initial set Cv value of 0.117 by about 15%, and the change of the Cv value is stabilized by 10,000 opening/closing aging.

その結果、図９に示すように、開閉エージングなしのバルブでは、１時間の開放置時間でＣｖ値が約30%低下したのに対し、開閉エージングを行ったバルブでは、Cv値低下がほとんど見られなかった。 Next, FIG. 9 is a graph showing changes in the Cv value due to being left open at 120° C.
The change in Cv value due to opening at 120° C. was compared and evaluated using three valves that were opened and closed aged 10,000 times with a lift amount of 0.3 mm and three valves that were not opened and closed aged.
Table 3 shows the test conditions.

As a result, as shown in FIG. 9, in the valve without opening/closing aging, the Cv value decreased by about 30% after 1 hour of open-duration, whereas in the valve subjected to opening/closing aging, the Cv value almost decreased. I couldn't.

It is considered that the reason why the change in Cv value after the opening and closing at 120° C. is reduced after the opening and closing aging is as follows.
As shown in FIG. 10, before opening and closing aging, there is a gap between molecules of the resin material such as PTFE and PFA forming the sheet, so that the sheet has room for deformation by the gap.
Next, when opening and closing aging is performed at 120° C., the sheet is repeatedly pressed and crushed, the gaps between the molecules are eliminated, and there is no room for deformation, so that the shape is stabilized.
Furthermore, when the sample is left open at 120°C, the gap between the crushed molecules slightly expands, increasing the room for deformation. However, there is less room for deformation than before opening and closing aging, so the amount of deformation is considered to be smaller.

(Summary of effects)
(1) Cv value stabilization effect by opening and closing aging By the opening and closing aging of the present embodiment, even with a small lift amount of 0.3 mm, the effect of sufficiently reducing the change in Cv value over time and the change in Cv value when left open at 120°C A reduction effect was confirmed.
In the opening and closing aging, the larger the lift amount, the larger the impact force at the time of closing, and thus the aging effect is considered to be large. However, in the present embodiment, the lift amount of the opening and closing aging in Patent Document 2 is smaller than about 1.1 mm. A sufficient effect was obtained even with an amount of 0.3 mm.

(2) Effect of opening/closing aging on diaphragm durability This time, no experiment was conducted, but empirically, if the lift amount used is 0.3 mm, the diaphragm durability is 40 million times in terms of actual opening/closing times. Therefore, it is considered that opening/closing aging about 10,000 times does not cause a problem in the durability of the diaphragm.
Let us consider a case where the lift amount ΔS during opening and closing aging is 0.4 mm. When the outer diameter of the diaphragm is D, the thickness is t, and the lift amount is ΔS, the strain amount ε due to opening and closing of the diaphragm is considered to be proportional to tΔS/D. When the diaphragm outer diameter D=26 mm, tΔS/D=0.015 t, when the diaphragm outer diameter D=20 mm, tΔS/D=0.02 t, and even when the diaphragm outer diameter D=15 mm, tΔS/D=0.027 t. (The outer diameter is 26 mm, the lift amount is 1.1 mm, and tΔS/D=0.042 t), the strain amount ε is smaller than that, and in this case, it is considered that opening/closing aging also has a small influence on the diaphragm life.

The present invention is not limited to the above embodiment. A person skilled in the art can make various additions and changes within the scope of the present invention.
For example, in the present embodiment, the manufacturing method of the present invention is applied to a diaphragm valve configured as an air operated valve using an air cylinder as an actuator, but the manufacturing method of the present invention is not limited to this, and a solenoid or a piezo element is used. It can also be applied to a diaphragm valve that uses an actuator.

1: Body 2: Diaphragm 3: Presser adapter 4: Bonnet 5: Screw part 6: Spring 7: Diaphragm presser 8: Stem 8a: Collar part 9: Actuator 9a: Supporting cylinder part (piston)
10: Fluid inlet 11: Fluid outlet 12: Valve chamber 13: Seat 14: Drive shaft 15: Stroke adjusting mechanism 15a: Lock nut 16: Solenoid valve 17: Proximity switch ΔS: Lift amount D: Diaphragm outer diameter t: Thickness ε: Strain amount

Claims (6)

A body having a valve chamber having an opening on the upper surface and having a fluid inflow passage and a fluid outflow passage respectively open at the bottom surface of the valve chamber,
An annular seat disposed around the opening of the fluid inflow passage on the bottom surface of the valve chamber,
A diaphragm that is arranged so as to seal the valve chamber and that closes and opens the fluid inflow passage by elastically deforming and abutting and separating from the seat,
A diaphragm operating portion, the tip end portion of which moves up and down while pressing the diaphragm to bring the diaphragm into contact with and away from the seat,
A method of manufacturing a diaphragm valve comprising:
A step of adjusting a rising amount of the tip end portion of the diaphragm operating portion to a predetermined amount when the diaphragm is separated from the sheet when the sheet is pressed;
After that, a step of performing a break-in operation in which the diaphragm is brought into contact with and separated from the seat by a predetermined number of times by the diaphragm operation section, is included. The method for manufacturing a diaphragm valve according to claim 1, wherein the step of performing the break-in operation is performed at any temperature within a temperature range of 80°C to 150°C. The method for manufacturing a diaphragm valve according to claim 2, wherein the temperature is an upper limit temperature of a use temperature range of the diaphragm valve. The diaphragm is a circular laminate having an outer diameter of 14.5 mm to 26.5 mm, which is a laminate of a stainless steel thin plate and a nickel-cobalt alloy thin plate, and the predetermined number of times is at least 10,000 times. A method for manufacturing a diaphragm valve according to any one of the above. The method for manufacturing a diaphragm valve according to claim 4, wherein the predetermined amount of the elastic deformation stroke is 0.3 mm to 0.4 mm. The method for manufacturing a diaphragm valve according to claim 1, further comprising a step of adjusting a Cv value of the diaphragm valve after the step of performing the break-in operation.

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