JP4575790B2 - Chemical valve - Google Patents

Description

  The present invention relates to a chemical valve that controls a corrosive fluid by bringing a valve body into contact with or separating from a valve seat communicating with an input port and an output port using a driving means.

Conventionally, as shown in FIGS. 3 to 5, for example, chemical valves that control corrosive fluid by bringing a valve body into contact with or away from a valve seat communicating with an input port and an output port by using a driving means. It has been. FIG. 3 is a side view of the chemical valve 100. FIG. 4 is a top view of the chemical valve 100. FIG. 5 is an enlarged cross-sectional view of a screw fastening portion in the conventional chemical valve 100.
As shown in FIGS. 3 and 4, the chemical valve 100 includes a cover 51, a cylinder 52, a body 53, and a mounting block 54, and four mounting screws 55 are inserted. As shown in FIG. The cover 51, the cylinder 52, the body 53, and the mounting block 54 are integrated to form an external appearance by fastening the tip of the mounting screw 55 to the insert metal fitting 56 that has been insert-molded in 54. When the metal is exposed to the outside, the chemical valve 100 is corroded by being exposed to a corrosive atmosphere. Therefore, as shown in FIG. 3, in the chemical valve 100, a recess 72 for accommodating the head 71 of the mounting screw 55 is formed in the cover 51, a cap 73 is attached to the opening of the recess 72, and the recess 72 Is isolated from the corrosive atmosphere (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 61-131511

  However, in the conventional chemical valve 100, although the metal such as the mounting screw 55 is not exposed in appearance, a gap is actually formed between the cover 51, the cylinder 52, the body 53, and the mounting block 54. The mounting screw 55 was exposed to a corrosive atmosphere. On the other hand, as shown in FIG. 3, it is considered that the attachment screw 55 may be coated with a coating C made of a corrosion resistant material such as PTFE (polytetrafluoroethylene).

  However, when the coating C is applied to the portion where the male screw of the mounting screw 55 is applied to the female screw of the insert fitting 56, the screw slips and the fastening force is weakened. Therefore, as shown in FIG. The coating C could not be applied to the part. As a result, the end surface of the insert fitting 56 is corroded by being exposed to a corrosive atmosphere through a gap formed between the body 53 and the mounting block 54, and the corrosion further occurs inside the insert fitting 56 and the tip of the mounting screw 55. The screw was thinned. In the case of the chemical valve 100 used for the main valve of the semiconductor manufacturing apparatus, a force of about 2 kN to 3 kN acts on the screw fastening portion when used. If the mounting screw 55 is thin, the screw fastening force becomes small, and the chemical valve 100 may not be able to withstand the force at the time of the on-off valve, and may break and fall apart.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a chemical valve that can isolate mounting screws exposed between blocks from a corrosive atmosphere.

The chemical valve according to the present invention has the following configuration.

(1) A valve body is brought into contact with or separated from a valve seat communicating with the first port and the second port using a driving means to control a corrosive fluid, and a plurality of blocks are integrated with mounting screws. In the chemical valve, the sealing valve is provided around the mounting screw and elastically deformed between the first block and the second block, and the first block connects the first port and the second port. The formed body, wherein the second block is a mounting block laminated on the body, and has an insert fitting that is insert-molded to the mounting block and to which the mounting screw is fastened. Is characterized in that a screw portion except a portion fastened to the insert fitting is coated with a corrosion-resistant material, and the sealing member is attached to the opening of the insert fitting.

  In the chemical valve having the above-described configuration, the first block and the second block are used when the corrosive fluid is controlled by bringing the valve body into contact with or separating from the valve seat communicating with the first port and the second port using a driving unit. Is exposed to a corrosive atmosphere, and the sealing member disposed between the first block and the second block is elastically deformed to seal around the mounting screw. The mounting screw exposed between the second block can be isolated from the corrosive atmosphere.

  In addition, when a sealing member is attached to the opening of the insert fitting that is insert-molded in the mounting block, the body is stacked on the mounting block, and the mounting screw is inserted from the body into the mounting block and fastened to the insert fitting. The sealing member covers the fastening part between the insert metal fitting and the mounting screw and isolates it from the corrosive atmosphere, and the mounting screw exposed from the other blocks by the coating is isolated from the corrosive atmosphere, preventing the screw from thinning. Thus, pressure resistance can be secured.

Next, an embodiment of a chemical valve according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the chemical valve 50.
The chemical valve 50 of the present embodiment is used as a main valve of a semiconductor manufacturing apparatus and controls a high-pressure corrosive fluid of 0.7 MPa or more. The chemical valve 50 includes a cover 51, a cylinder 52, a body 53, and four mounting screws 55 that are inserted into the mounting block 54. 53 and the mounting block 54 are integrated, and the external appearance is comprised. The cover 51, the cylinder 52, the body 53, and the mounting block 54 are made of PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), PP (polypropylene), PPS (polyphenylene sulfide), etc., in order to ensure corrosion resistance. A resin is injection-molded.

  The cylinder 52 has a substantially cylindrical shape opened at one end, and the opening is closed by the cover 51 to form a piston chamber 57. A piston 58 is slidably loaded in the piston chamber 57, and the piston chamber 57 is airtightly divided into an upper chamber 57a and a lower chamber 57b. A compression spring 59 is contracted in the upper chamber 57a, and a downward force is applied to the piston 58 in the drawing. A breathing hole 60 communicates with the upper chamber 57a, and an operation port 61 communicates with the lower chamber 57b. By supplying compressed air to the operation port 61, an upward force in the figure is applied to the piston 58 to compress it. By stopping the supply of air, the upward force in the figure can be released. A valve shaft 62 is fixed to the piston 58, and a lower end portion of the valve shaft 62 extends through the cylinder 52 and protrudes from the body 53.

  The body 53 has a block shape, an input port 63 and an output port 64 are formed, and a valve seat 65 is provided in a cylindrical shape therebetween. The body 53 holds the outer edge portion of the diaphragm 66 between the lower end surface of the cylinder 52. The diaphragm 66 hermetically partitions a space formed between the cylinder 52 and the body 53 to form a valve chamber 67. The diaphragm 66 has a valve shaft 62 connected to a central portion via a diaphragm receiver 68 so that a driving force in the vertical direction in the figure can be applied.

  An attachment block 54 for assembling the chemical valve 50 to the semiconductor manufacturing apparatus is attached to the bottom surface of the body 53. The mounting block 54 has a plate shape and is provided with a plurality of insertion holes for inserting assembly screws. In the mounting block 54, an insert fitting 56 is embedded by insert molding, and a step 69 is provided along the opening of the insert fitting 56 by a mold used at the time of molding. An attachment screw 55 inserted from the body 53 side is fastened to the insert fitting 56, and the fastening portion is sealed with the sealing member 1.

FIG. 2 is an enlarged view showing the sealing structure.
The sealing member 1 is formed by molding an elastic material such as NBR (nitrile rubber), FKM (fluoro rubber), or FFKM (perfluoroelastomer) into a substantially cylindrical shape. The sealing member 1 includes a crushing margin 2 and a guide portion 3 with the outer peripheral surface formed in a step shape. A step-shaped space for compressing and holding the sealing member 1 is formed between the body 53 and the mounting block 54, and the body 53 and the mounting block 54 are brought into surface contact even when the sealing member 1 is interposed. It is supposed to be. In the body 53, the fitting recess 4 is formed in a cylindrical shape having a diameter larger than that of the step 69 on the same axis as the insertion hole through which the attachment screw 54 is inserted, from the side surface in contact with the attachment block 54. The squeezing margin 2 of the sealing member 1 is formed slightly larger than the fitting recess 4, is sandwiched in the axial direction between the bottom surface of the fitting recess 4 and the side surface of the mounting block 54, elastically deforms, and has a sealing force. It has been made to demonstrate. The crushing margin 2 is continuously provided with a guide portion 3 that is pushed into and attached to the step 69 so as to abut against the end surface of the insert fitting 56. The guide portion 3 is formed to be slightly larger than the step 69 and is guided by the step 69 of the mounting block 54 so that the sealing member 1 does not fall off even if the mounting block 54 is turned upside down. It has good characteristics. In the sealing member 1, a through hole 5 having a diameter smaller than that of the mounting screw 55 is formed at the center, and the inner peripheral surface of the through hole 5 is tapped when the mounting screw 55 is screwed into the insert fitting 56.

As shown in FIGS. 3 and 4, in the chemical valve 50, the head 71 of the mounting screw 55 is accommodated in the recess 72 formed in the cover 51, and the opening of the recess 72 is capped, as in the prior art. The head portion 71 is prevented from being corroded by covering the concave portion 72 with the cover 53.
Further, the mounting screw 55 is coated with a corrosion-resistant material C (see the point in FIG. 2) except for the tip portion screwed into the insert fitting 56 to prevent corrosion.

  In such a chemical valve 50, when compressed air is not supplied to the operation port 61, the diaphragm 66 is pressed against the valve seat 65 by the elastic pressure of the compression spring 59 to block the corrosive fluid. When compressed air is supplied to the operation port 61 and the piston 58 is raised against the compression spring 59, the diaphragm 66 is separated from the valve seat 65, and corrosive fluid flows from the input port 63 to the output port 64. Thereafter, when the supply of compressed air is stopped, the diaphragm 66 is lowered by the elastic pressure of the compression spring 59 to seal the valve seat 65.

  The chemical valve 50 is exposed to a corrosive atmosphere in order to control a corrosive fluid. The corrosive atmosphere also enters a gap formed between the cover 51, the cylinder 52, the body 53, and the mounting block 54. Although the male screw portion of the mounting screw 55 is exposed between the cover 51 and the cylinder 52 and between the cylinder 52 and the body 53, the exposed portion is coated with the coating C, so that it does not corrode. The tip of the mounting screw 55 is not coated with C, but the sealing member 1 is crushed between the body 53 and the mounting block 54 and elastically deformed to exert a sealing force. In addition, the sealing member 1 is tapped when the mounting screw 55 is screwed, and is in close contact with the outer periphery of the tip of the mounting screw 55. Therefore, even if the space between the body 53 and the mounting block 54 is exposed to a corrosive atmosphere, the sealing member 1 covers the insert fitting 56 and the tip of the mounting screw 55 and isolates them from the corrosive atmosphere.

  As described above, according to the chemical valve 50 of the present embodiment, when the diaphragm 66 is brought into contact with or separated from the valve seat 65 according to the vertical movement of the piston 58 to control the corrosive fluid, The space between the mounting block 54 and the mounting block 54 is exposed to a corrosive atmosphere, but the sealing member 1 disposed between the body 53 and the mounting block 54 is elastically deformed to seal around the mounting screw 55 ( The mounting screw 55 exposed from between the body 53 and the mounting block 54 can be isolated from the corrosive atmosphere. In particular, in addition to the sealing member 1, the head 71 of the mounting screw 55 is covered with a cap 73 and sealed in the recess 72, or the mounting bolt 55 is coated C, so that the exposed portion of the mounting screw 55 is completely covered. Can be isolated from corrosive atmosphere.

  Further, the inner diameter of the sealing member 1 is formed to be smaller than the outer diameter of the mounting screw 55, and the mounting screw 55 is screwed into the cover 51, cylinder 52, body 53, sealing member 1, and mounting block 54. Since the sealing member 1 is tapped at 55 so that the sealing member 1 is in close contact with the outer peripheral surface of the mounting screw 55 (see FIG. 2), the mounting screw 55 can be more reliably isolated from the corrosive atmosphere. .

  In addition, the sealing member 1 is attached to the opening of the insert fitting 56 that is insert-molded in the mounting block 54, and the body 53, the cylinder 52, the cover 51, and the like are sequentially stacked on the mounting block 54. When the tip of the mounting screw 55 is fastened to the insert fitting 56 through the cylinder 52, the body 53, and the mounting block 54, the sealing member 1 covers the fastening portion between the insert fitting 56 and the mounting screw 55 and corrodes. The mounting screw 55 exposed from between the cover 51 and the cylinder 52 or between the cylinder 52 and the body 53 is isolated from the corrosive atmosphere by the coating C (see FIG. 2). Can be prevented and pressure resistance can be secured.

  In particular, when the high-pressure corrosive fluid is controlled as in the present embodiment, a force of about 2 kN to 3 kN acts on the fastening portion of the screw. However, since the chemical valve 50 prevents the insert fitting 56 and the mounting screw 55 from being corroded by the sealing member 1, it can maintain the initial fastening force at which the mounting screw 55 is fastened. It cannot withstand elastic pressure and will not break down and fall apart.

  Although the embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various applications are possible.

(1) For example, in the said embodiment, the coating C was given to the part exposed between the cover 51 and the cylinder 52 of the attachment screw 55, and the part exposed between the cylinder 52 and the body 53, and corrosion was prevented. . On the other hand, the sealing member 1 may be disposed between the cover 51 and the cylinder 52 and between the cylinder 52 and the body 53 to prevent corrosion.

(2) For example, in the above embodiment, the sealing member 1 is tapped, and the male screw portion of the mounting screw 55 and the inner peripheral surface of the sealing member 1 are brought into close contact with each other. On the other hand, if the sealing member 1 of the mounting screw 55 can be elastically deformed to exhibit a sealing force, the sealing member 1 is formed in a cylindrical shape having a larger diameter than the mounting screw 55, and the mounting screw 55 and the sealing member 1 are formed. There may be a gap between them.

(3) For example, in the above embodiment, the through hole 5 is formed in the sealing member 1 in advance, but the through hole may be formed in the sealing member 1 only by tapping the mounting screw 55.

(4) For example, in the said embodiment, although the sealing member 1 was attached to the chemical | medical solution valve 50 which controls a high pressure corrosive fluid, you may attach the sealing member 1 to the chemical | medical solution valve 50 of a low voltage | pressure or an intermediate pressure. The chemical valve 50 is a two-port air operated valve, but may be a three-port air operated valve. The driving method is not limited to the air operated method, and other driving means such as a manual valve may be used.

It is a center longitudinal cross-sectional view of a chemical | medical solution valve concerning embodiment of this invention. Similarly, it is an enlarged view showing a sealing structure. It is a side view of a chemical | medical solution valve. It is a top view of a chemical | medical solution valve. It is an expanded sectional view of the screw fastening part in the conventional chemical | medical solution valve.

Explanation of symbols

1 Sealing member 50 Chemical valve 53 Body 54 Mounting block 55 Mounting screw 56 Insert metal fitting 63 Input port 64 Output port 65 Valve seat 66 Diaphragm

Claims (1)

A chemical valve for controlling a corrosive fluid by bringing a valve body into contact with or separating from a valve seat communicating with a first port and a second port using a driving means and integrating a plurality of blocks with mounting screws In
A sealing member provided around the mounting screw and elastically deformed between the first block and the second block;
A body in which the first block is formed with the first port and the second port;
The second block is a mounting block laminated on the body,
Insert molding is performed on the mounting block, and the mounting screws are fastened to the mounting screws.
Corrosion-resistant material is coated on the screw portion except the portion where the mounting screw is fastened to the insert fitting,
The chemical valve, wherein the sealing member is attached to an opening of the insert fitting.

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