JP5184481B2 - Chemical valve - Google Patents

Description

  The present invention relates to a resin chemical valve used in a semiconductor manufacturing process and the like, and more particularly, to a chemical valve having a seal structure that prevents corrosion of a metal due to a chemical gas that has permeated through a thin film portion of a diaphragm or bellows.

  In the semiconductor manufacturing process, highly corrosive chemicals are used. Therefore, the chemical valve that controls the supply of chemical liquid is made of a material such as fluororesin that has corrosion resistance in its valve body, and the flow path section where the chemical liquid flows and the actuator section that operates opening and closing of the valve are shut off. Resin is also used for the diaphragm valve body. The diaphragm has an annular fixed portion formed on the outer periphery thereof, which is sandwiched and attached to the valve body, and sealing is performed at that portion.

  However, such a chemical valve has a problem in that the sealing force is reduced by using the chemical valve for a long period of time because the seal portion is pressed between the resins. In order to solve such a problem, Patent Document 1 described below describes a configuration in which an annular convex portion 115 formed in a fixed portion 111 of a diaphragm 110 is press-fitted into an insertion groove 120 formed in a valve body, as shown in FIG. . A structure is described in which the annular convex portion 115 is elastically deformed outward and brought into contact with the radially inner inner annular seal portion 121 and the outer outer annular seal portion 122 for sealing. In addition, Patent Document 2 described below describes a structure in which, as shown in FIG. 9, even if the force for holding the diaphragm 150 is weakened, the structure is made up by the elastic force of the O-ring 160.

JP 2007-321958 A JP 2003-247650 A

  By the way, although the amount of hydrofluoric acid used as a chemical solution handled by the chemical valve is very small, the gas passes through the thin film portion 112 of the diaphragm 110 shown in FIG. 8 and enters the actuator side. Chemical liquid gas such as hydrofluoric acid gas that has permeated through the thin film will corrode metal parts such as fixing bolts, so a breathing hole is formed on the actuator side so that the chemical liquid gas does not stay in the valve. To be released. However, not all of the permeated chemical gas is released to the outside, but a part of it stays, so the problem that it penetrates into the inside and corrodes the fixing bolt over time has not been solved. .

  As described above, the conventional chemical liquid valve is configured in consideration of leakage of the chemical liquid itself. As shown in FIG. 8, only the seal on the flow path side (lower side of the drawing) partitioned by the diaphragm 110 is considered. . On the other hand, in order to prevent the flow of the chemical gas to the fixing bolt, as shown in FIG. 9, it is effective to adopt a seal structure in which an O-ring 160 is arranged on the actuator side in the fixing portion 151 of the diaphragm 150. . However, this configuration uses the elastic force of the O-ring 160 as described above, and has an effect that is not intended initially. In addition, the seal structure using the O-ring 160 has a problem of forgetting the assembly in addition to an increase in the number of parts.

  In view of the above, an object of the present invention is to provide a chemical valve that seals an actuator side of a fixed portion of a diaphragm without adding the number of parts.

The chemical valve according to the present invention includes a flow path portion formed by a resin member including a primary flow path and a secondary flow path and a valve seat therebetween, and a valve that contacts and separates from the valve seat. An actuator portion formed by a resin member that moves the body is integrally assembled using a metal bolt, and the valve body is in contact with or separated from the valve seat; It is made of resin and includes a film part that blocks the chemical solution flowing through the passage part from flowing to the actuator part, and a fixed part that is sandwiched between members that constitute the flow path part and the actuator part. is, there is the breathing hole for discharging the gas in which the chemical solution is passed through the membrane unit gasified is formed, the pressing surface of the member to hold down the fixing portion of the actuator unit, the hold-down direction Protruding ring A convex portion is formed, and has a seal portion that prevents the gas permeated from the film portion from reaching the bolt on the actuator portion side by pressing and deforming the fixed portion by the annular convex portion. It is characterized by being.

In the chemical valve according to the present invention, the flow passage portion is formed with an annular insertion groove, and the fixing portion has an L-shaped cross section and has a press-fit annular convex portion that is press-fitted into the insertion groove. The pressing portion that performs sealing by pressing and deforming the fixed portion with the annular convex portion is positioned on the inner side of the contact surface on which the annular convex portion for press-fitting contacts the inner surface of the insertion groove and performs sealing. It is preferable.
Moreover, it is preferable that the said chemical | medical solution valve of this invention makes the said sealing part bite the said cyclic | annular convex part by which the cross section was formed in the trapezoid in the flat surface of the said fixing | fixed part.
Moreover, it is preferable that the said chemical | medical solution valve of this invention makes the said seal | sticker part bite into the flat surface of the said fixing | fixed part the said cyclic | annular convex part formed in the cross section in the triangle .

  In the conventional chemical liquid valve, the chemical liquid is gasified and permeates through the membrane portion of the valve body and corrodes the metal bolt on the actuator portion side. According to the chemical valve of the present invention, since the annular convex portion presses and seals the fixed portion of the valve body, the chemical gas that has permeated from the membrane portion of the valve body does not reach the bolt on the actuator side. Bolt corrosion can be prevented.

It is the top view which showed the chemical | medical solution valve of embodiment. It is sectional drawing which showed the chemical | medical solution valve of FIG. 1 by the AA arrow. It is sectional drawing which showed the chemical | medical solution valve of FIG. 1 by the BB arrow. It is the expanded sectional view which showed the attachment state of the fixing | fixed part of a diaphragm valve body. It is an expanded sectional view of the modified example which showed the attachment state of the fixing | fixed part of a diaphragm valve body. It is an expanded sectional view of the other modification which showed the attachment state of the fixing | fixed part of a diaphragm valve body. It is an expanded sectional view of the other modification which showed the attachment state of the fixing | fixed part of a diaphragm valve body. It is an expanded sectional view of the prior art example which showed the attachment state of the fixing | fixed part of a diaphragm valve body. It is an expanded sectional view of the prior art example which showed the attachment state of the fixing | fixed part of a diaphragm valve body.

  Next, an embodiment of a chemical valve according to the present invention will be described below with reference to the drawings. 1 is a plan view showing a chemical valve, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line BB in FIG. The chemical liquid valve 1 is piped to, for example, a semiconductor manufacturing apparatus and is used for adjusting the flow rate of the chemical liquid.

  The chemical liquid valve 1 is composed of a flow path section 2 through which a chemical liquid flows and an actuator section 3 that operates opening and closing of the valve, and is inserted from the actuator section 3 side to the flow path section 2 side as shown in FIG. The fixing bolts 5 are assembled together. The fixing bolt 5 is inserted through a washer 6 and is screwed to a nut (not shown) on the flow path portion 2 side. Metals such as the fixing bolt 5, the washer 6, and the nut are coated (fluororesin coating) so as not to be corroded by the chemical solution.

  An input port 22 and an output port 23 are formed with respect to the valve body 21 in the flow path portion 2 constituting the chemical liquid valve 1, and a valve portion is formed therebetween. In the valve portion, a valve seat 24 that contacts and separates the valve body protrudes toward the actuator portion 3 side. The valve body 21 includes a primary flow path that flows from the input port 22 to the inside of the valve seat 24, and a valve seat. A secondary-side flow path that flows to the outside of 24 and continues to the output port 23 is formed. The valve body 24 has a valve seat 24 portion opened upward, and the diaphragm valve body 10 is attached so as to close the opening portion.

  The diaphragm valve body 10 has a valve body portion 11 that contacts and separates from the valve seat 24 in the center, a thin film portion 12 that is curved and spreads in a circular shape around the valve body portion 11, and is fixed to the peripheral portion with a thick wall. Part 13 is formed. In the diaphragm valve body 10, the fixed portion 13 is sandwiched between the valve body 21 of the flow path portion 2 and the cylinder 31 of the actuator portion 3, and is incorporated into the chemical valve 1. In the diaphragm valve body 10, the valve body portion 11 is moved up and down by the actuator portion 3 to open and close the valve, and the thin film portion 12 blocks the flow path portion 2 side to block the flow of the chemical solution to the actuator portion 3. .

  On the other hand, the actuator part 3 is a piston cylinder that outputs vertical movement by operating air, and a piston part 32 a of a piston rod 32 is slidably inserted into the cylinder 31. The piston rod 32 is integrally formed with a rod portion 32b protruding downward from the piston portion 32a, and the valve body portion 11 of the diaphragm valve body 10 is connected to the lower end portion thereof. Further, the rod portion 32b is inserted into the guide portion 31a of the cylinder 31, and is configured to be able to move up and down accurately in the axial direction.

  A cover 34 is placed on the top of the cylinder 31, and a spring 35 is loaded between the cylinder 31 and the piston rod 32. The valve body 11 of the diaphragm valve body 10 is biased so as to be pressed against the valve seat 24 by the spring 35. The actuator unit 3 is an air operated valve that moves the piston rod 32 up and down by operating air to cause the diaphragm valve body 10 to open and close. The cylinder 31 is provided with an air supply / exhaust port 36 for operating air, and the cover 34 is for breathing. A port 37 is formed.

  In such a chemical valve 1, the piston rod 32 is normally biased downward by the biasing force of the spring 35, and the diaphragm valve body 10 connected to the rod portion 32b causes the valve body portion 11 to abut against the valve seat 24. It is pressed down. That is, this chemical valve 1 is a normally closed on-off valve, and the chemical liquid that has entered from the input port 22 is blocked and does not flow to the secondary side of the output port 23. On the other hand, when working air is supplied from the air supply / exhaust port 36, the piston portion 32 a is pressurized from below and rises against the urging force of the spring 35. Therefore, the valve body part 11 of the diaphragm valve body 10 is lifted away from the valve seat 24, and the chemical liquid flows to the secondary side.

  In this way, the chemical valve 1 that controls the supply of the chemical solution is blocked by the thin film portion 12 of the diaphragm valve body 10 so that the chemical solution does not flow into the actuator portion 3. However, hydrofluoric acid, which is a chemical solution, gasifies and permeates the thin film portion 12 of the diaphragm valve body 10, and the hydrofluoric acid gas penetrates into the actuator portion 3. Such chemical gas such as hydrofluoric acid gas has a problem of corroding the fixing bolt 5 which is a metal part. Therefore, in order to solve this problem, the chemical valve 1 of the present embodiment is provided with a seal structure on the actuator part 3 side with respect to the fixed part 13 of the diaphragm valve body 10.

  In the case of the chemical valve 1, the chemical solution is filled in the valve chamber 25 below the diaphragm valve body 10, the chemical liquid is gasified and permeates the thin film portion 12, and chemical liquid gas is generated in the space 26 above the diaphragm valve body 10. The chemical gas is released through a breathing hole 38 formed in the cylinder 31 shown in FIG. The breathing hole 38 is intended to facilitate the operation of the diaphragm valve body 10 when the pressure is increased due to the sealing of the space 26. In this embodiment, the breathing hole 38 releases the chemical gas to the outside. It also plays a function. However, even if there is such a breathing hole 38, the chemical gas in the space 26 is not positively released, so that the gas that stays by itself alone is fixed to the diaphragm valve body 10 shown in FIG. The portion 13 and the cylinder 31 penetrate through the abutted gap and reach around the fixing bolt 5. Therefore, the chemical valve 1 of the present embodiment is configured to prevent the penetration of chemical gas into the fixing bolt 5 as described below.

  For the formation of the valve body 21 and the cylinder 31, polyphenylene sulfide resin (PPS), polypropylene (PP), or the like is used as corrosion resistance. The diaphragm valve body 10 is flexible and is resistant to hydrofluoric acid. A durable Teflon (registered trademark) resin (PTFE) is used. Therefore, also in the chemical valve 1 of the present embodiment, the seal portion is pressed between the resins.

  Here, FIG. 4 is an enlarged cross-sectional view showing a mounting state of the fixed portion 13 portion of the diaphragm valve body 10. The fixed portion 13 has an L-shaped cross section and is formed with an annular protrusion 131, and is press-fitted into an annular insertion groove 210 formed in the valve body 21. The annular protrusion 131 is in contact with the side surface of the insertion groove 210 and can maintain a seal so that the chemical solution in the valve chamber 25 does not leak.

  In the cylinder 31, an annular convex portion 311 is formed on the pressing surface 310 at the lower end for pressing the fixed portion 13 of the diaphragm valve body 10. In the present embodiment, the annular convex portion 311 is sealed by contacting the fixed portion 13 of the diaphragm valve body 10 so as to bite. Since the material of the cylinder 31 is harder than that of the diaphragm valve body 10, the annular convex portion 311 causes the flat fixed portion 13 to be recessed as illustrated by pressing.

  In the chemical liquid valve 1, the chemical liquid flows into the valve chamber 25, but sealing is performed by the contact surface of the fixed portion 13 pressed against the valve body 21 and the cylinder 31, and liquid leakage can be prevented. On the other hand, most of the chemical liquid gas that has permeated through the thin film portion 12 of the diaphragm valve body 10 is released from the space 26 through the breathing hole 38, but a part of it takes time in the gap between the cylinder 31 and the fixed portion 13. To penetrate. However, in this embodiment, since the annular convex portion 311 bites into the fixed portion 13 and seals it, further intrusion can be prevented. Therefore, the chemical gas does not reach the fixing bolt 5.

  Therefore, in this embodiment, it is possible to prevent the fixing bolt 5 from being corroded by reliably sealing, and to extend the life of the chemical valve 1. Further, since the sealing is performed by the annular convex portion 311 formed on the cylinder 31, it is not necessary to separately prepare a sealing member such as an O-ring, and the problem of forgetting to attach it during assembly is solved.

  Next, FIG. 5 is an enlarged cross-sectional view showing a state where the fixed portion 13 of the diaphragm valve body 10 is attached, and is a view showing a modified example of the chemical gas sealing structure. In the embodiment shown in FIG. 4, the convex portion is pressed against the upper surface of the fixed portion 13 of the flat diaphragm valve element 10, but in this embodiment, the annular concave portion 132 of the fixed portion 13 is formed in advance. An annular convex portion 312 that fits into the annular concave portion 132 is formed on the pressing surface 310 of the cylinder 31. The annular convex portion 312 and the annular concave portion 132 are configured with a vertical side surface whose cross section is a pressing direction and a horizontal plane perpendicular to the vertical direction.

  Therefore, in the present embodiment, the annular convex portion 312 fits into the annular concave portion 132 of the fixed portion 13 and is sealed by the side surface and the horizontal surface to prevent the intrusion of the chemical gas. Even if the chemical valve 1 is used for a long period of time, the sealing performance is maintained because the side surfaces of the annular convex portion 312 and the annular concave portion 132 are in contact with each other. In this case, it is preferable that the depth of the annular concave portion 132 is made smaller than the height of the annular convex portion 312 so that the tip of the annular convex portion 312 is pressed against the bottom surface of the annular concave portion 132 during assembly.

  Thereby, since the annular convex part 312 of the cylinder 31 is always in contact with the fixed part 13 of the diaphragm valve body 10, the tip surface perpendicular to the pushing direction of the annular convex part 312 and the side surface parallel to the pushing direction are in contact. Even if the chemical gas in the space 26 has permeated into the gap between the cylinder 31 and the fixing portion 13, the sealing bolt 5 can be prevented from corroding by reliably sealing, and the life of the chemical valve 1 can be extended. It became possible. In particular, in the present embodiment, the annular recess 132 is formed so that the annular projection 312 is in contact with a wide surface. Therefore, higher sealing performance can be obtained in this respect. Furthermore, such a seal structure does not cause problems such as forgetting to attach the seal member during assembly.

  Further, FIG. 6 is an enlarged cross-sectional view showing an attachment state of the fixed portion 13 portion of the diaphragm valve body 10, and is a view showing another modified example of the sealing structure of the chemical gas. In the example shown in FIG. 4, the annular convex portion having a symmetrical trapezoidal shape is pressed against the upper surface of the fixed portion 13 of the flat diaphragm valve element 10, but in this embodiment, the inner diameter side surface is parallel to the pressing direction. An annular convex portion 313 having a side surface 330 and having a trapezoidal cross section is pressed. That is, the annular convex portion 311 shown in FIG. 4 has a shape that combines the effects of the annular convex portion 312 shown in FIG. Note that the annular convex portion 313 may have a trapezoidal cross section with the outer diameter side surface having an outer surface parallel to the pressing direction opposite to the inner surface 330.

  Therefore, when the cylinder 31 and the valve body 21 are assembled, the annular convex portion 313 formed on the pressing surface 310 at the lower end of the cylinder 31 is pressed against the fixed portion 13 of the diaphragm valve body 10 as shown in the figure. Therefore, a part of the chemical liquid gas that has permeated through the thin film portion 12 of the diaphragm valve body 10 penetrates into the gap between the cylinder 31 and the fixed portion 13, but is prevented by the seal of the annular convex portion 313 that bites into the fixed portion 13. The above penetration is prevented. The sealing property is also maintained by the inner surface 330 being in contact with the fixed portion 13.

  Therefore, since the annular convex portion 313 of the cylinder 31 is always in contact with the fixed portion 13 of the diaphragm valve body 10, even if the chemical gas in the space 26 has permeated into the gap between the cylinder 31 and the fixed portion 13, the sealing is surely performed. As a result, corrosion of the fixing bolt 5 can be prevented, and the life of the chemical valve 1 can be extended. Furthermore, such a seal structure does not cause problems such as forgetting to attach the seal member during assembly.

  FIG. 7 is an enlarged cross-sectional view showing a state where the fixed portion 13 of the diaphragm valve body 10 is attached, and is a view showing another modified example of the sealing structure of the chemical gas. Each of the annular convex portions 311 to 313 shown in FIG. 4 to FIG. 6 has a shape in which a flat surface is formed at the tip in the pushing direction, but this embodiment has a cross section so that the tip in the pushing direction is a curved surface. Is formed with a substantially semicircular annular convex portion 314. The annular convex portion 314 has a curved surface as a whole. However, the annular convex portion 314 may have a shape having a side surface parallel to the pressing direction or an inclined slope.

  Therefore, when the cylinder 31 and the valve body 21 are assembled, the annular convex portion 314 formed on the pressing surface 310 at the lower end of the cylinder 31 is pressed against the fixed portion 13 of the diaphragm valve body 10 as shown in the drawing. Therefore, a part of the chemical gas that has permeated through the thin film portion 12 of the diaphragm valve body 10 penetrates into the gap between the cylinder 31 and the fixed portion 13, but it is sealed by the seal of the annular convex portion 314 that bites into the fixed portion 13. The above penetration is prevented. Accordingly, the sealing bolt 5 can be prevented from corroding by sealing, and the life of the chemical valve 1 can be extended. Furthermore, such a seal structure does not cause problems such as forgetting to attach the seal member during assembly.

As mentioned above, although embodiment was shown and demonstrated about the chemical | medical solution valve which concerns on this invention, this invention is not necessarily limited to embodiment, A various change is possible in the range which does not deviate from the meaning.
For example, in the above embodiment, the flow path portion 2 and the actuator portion 3 are partitioned by the diaphragm valve body 10 so that the chemical liquid does not flow to the actuator portion 3 side. May be used.
For example, the annular convex portions 311 and 313 shown in FIGS. 4 and 6 have trapezoidal protrusions with a flat tip, but may have a triangular protrusion with a sharp tip. .

DESCRIPTION OF SYMBOLS 1 Chemical liquid valve 2 Flow path part 3 Actuator part 5 Fixing bolt 10 Diaphragm valve body 11 Valve body part 12 Thin film part 13 Fixing part 21 Valve body 24 Valve seat 31 Cylinder 32 Piston rod 36 Supply / exhaust port 38 Breathing hole 310 Pressing surface 311 Annular projection

Claims (4)

A flow path portion formed by a resin member having a primary side flow path and a secondary side flow path and a valve seat therebetween, and a resin made to operate a valve body that contacts and separates from the valve seat The actuator portion formed by the member is integrally assembled using a metal bolt, the valve body is in contact with and separated from the valve seat, and the chemical liquid flowing through the flow path portion is It is made of resin and includes a membrane part that is blocked so as not to flow to the actuator part, and a fixed part that is sandwiched between the flow path part and a member constituting the actuator part, and the chemical liquid is gasified in the actuator part. in the chemical liquid valve breathing hole for discharging are formed a gas having passed through the membrane portion Te,
An annular convex portion that protrudes in the pressing direction is formed on the pressing surface of the member that presses down the fixed portion of the actuator portion, and the fixed portion is pressed and deformed by the annular convex portion, and is transmitted from the film portion. A chemical valve having a seal portion that prevents the gas from reaching the bolt on the actuator portion side . In the chemical valve according to claim 1,
The channel portion is formed with an annular insertion groove,
The fixing portion has an L-shaped cross section and has a press-fitting annular convex portion that is press-fitted into the insertion groove,
The pressing portion that performs sealing by pressing and deforming the fixed portion with the annular convex portion is located on the inner side of the contact surface where the annular convex portion for press-fitting is in contact with the inner surface of the insertion groove and performs sealing. A chemical valve characterized by that. In the chemical valve according to claim 1 or 2 ,
The chemical valve according to claim 1, wherein the seal portion is configured such that the annular convex portion having a trapezoidal cross section is caused to bite into a flat surface of the fixed portion. In the chemical valve according to claim 1 or 2 ,
The chemical valve according to claim 1, wherein the seal portion is configured such that the annular convex portion having a triangular cross section is caused to bite into a flat surface of the fixed portion .

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