JP2019178757A - Diaphragm flow control valve - Google Patents

Abstract

To allow for proper control operation even for high-temperature fluid.SOLUTION: A diaphragm flow control valve is enclosed by upper and lower housings formed by injection molding of thermoplastic fluorine resin, and the upper housing is formed with an inflow pipe 1c and an outflow pipe 1d at an upper portion, and a vacant chamber 1e at a lower portion. A separate orifice portion 4 is disposed between the outflow pipe 1d and the vacant chamber 1e, and the vacant chamber 1e and the inflow pipe 1c are communicated to each other. A separate diaphragm portion 5 is disposed at a lower portion of the upper housing, the diaphragm portion 5 has a needle-shaped valve element 5b, and a flange 5d is formed at the periphery of the diaphragm portion 5 through a diaphragm film 5c. The orifice portion 4 and the diaphragm portion 5 are formed by cutting a non-meltable fluorine resin, and welded to the upper housing by laser beam. The fluid flowing from the inflow pipe 1c reaches the outflow pipe 1d through the orifice portion 4, and a vertical position of the valve element 5b inserted into the orifice portion 4 is adjusted to control a fluid flow volume.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a diaphragm type flow control valve used in, for example, a semiconductor manufacturing apparatus.

  In order to control a minute flow rate with high accuracy, a diaphragm type flow rate control valve as disclosed in the cited document 1 is often used. In this flow control valve, the diaphragm valve having a needle is made separately, but the orifice is provided integrally with a part of the body.

  In such a flow control valve, when a normal fluid such as water is used as a target, if a thermoplastic resin is used as a material, it can be manufactured at low cost by being manufactured by injection molding.

  In semiconductor production lines and the like, strong acids and high-temperature fluids are often used, and flow control valves are required to have chemical resistance and other performance, so fluororesin is used as a material. For example, if a thermoplastic fluororesin such as PFA (Tetrafluoroethylene Perflouroalkoxy vinyl ether copolymer) is used as the material, it can be produced by injection molding.

  However, if the fluid to be controlled is a high-temperature fluid such as sulfuric acid exceeding 150 ° C., for example, the thermoplastic fluororesin is easily softened by this high-temperature fluid, and in particular, the predetermined dimensional accuracy near the valve portion cannot be maintained. A good control action cannot be expected.

  Therefore, in order to prevent deformation due to high-temperature fluid and control it accurately, use non-melting fluororesin with heat resistance such as PTFE (Polytetrafluoroethylene) or modified PTFE for the diaphragm valve and body of the main part. Is needed. However, since this non-melting fluororesin is difficult to be thermoformed such as injection molding, it is laborious and expensive because it is manufactured by cutting.

Japanese Patent No. 2999429

  The purpose of the present invention is to solve the above-mentioned problems, by fixing an orifice part made of a heat-resistant resin to a thermoformed resin housing and cooperating with a diaphragm part made of the same heat-resistant resin, An object of the present invention is to provide a diaphragm type flow rate control valve that allows good control without deformation of the orifice portion even in the case of high-temperature fluid.

  In order to achieve the above object, a diaphragm type flow control valve according to the present invention includes a housing to which a pair of pipes can be connected, a cylindrical orifice portion fixed to the housing, and inserted into the orifice portion. A diaphragm-type flow rate control comprising a diaphragm portion provided with a valve body and fixed to the housing, and a fluid to be controlled extending from one of the tube bodies to the other tubular body through the orifice portion and the valve body The valve is characterized in that the housing is made of thermoformed resin, and the orifice part and the diaphragm part are made of heat-resistant resin.

  According to the diaphragm type flow control valve according to the present invention, the housing is made of thermoplastic fluororesin, and the orifice part made separately from non-melting fluororesin is fixed to the housing. Manufacture is possible, the price is low, and high-precision fluid control is possible.

It is a perspective view of a diaphragm type flow control valve. It is sectional drawing. It is a disassembled perspective view.

The present invention will be described in detail based on the embodiments shown in the drawings.
1 is a perspective view of a diaphragm type flow control valve, FIG. 2 is a sectional view, and FIG. 3 is an exploded perspective view.

  In the embodiment, the diaphragm flow control valve 10 is placed on the drive unit 20. The flow control valve 10 is surrounded by an upper housing 1 and a lower housing 2 that are vertically overlapped, and the upper and lower housings 1 and 2 are each formed of thermoplastic fluororesin such as PFA by thermoforming such as injection molding.

  A valve portion is disposed between the upper and lower housings 1 and 2 made of thermoformed resin, and flanges 1a and 2a are provided around the upper housing 1 and the lower housing 2, respectively. Insertion holes 1b and 2b are provided. Furthermore, a plurality of bolts 3 made of engineering plastic such as PEEK or SUS are inserted into the insertion holes 1b and 2b so that the upper and lower housings 1 and 2 are connected to each other.

  In the upper part of the upper housing 1, a tube body of an inflow pipe 1c and an outflow pipe 1d is integrally formed in the horizontal direction, and an empty chamber 1e is formed in the lower part. Between the outflow pipe 1d and the empty chamber 1e, a circular hole portion 1f for attaching an orifice portion 4 to be described later is provided, and the empty chamber 1e and the inflow tube 1c are communicated by a passage 1g. An annular recess 1h is formed inside the flange 1a.

  Although the inflow pipe 1 c and the outflow pipe 1 d are not necessarily provided in the upper housing 1, an inlet / outlet that allows the fluid to flow out to the upper housing 1 is formed in the upper housing 1. You may make it connect a tubular body.

  The orifice portion 4 is formed by cutting into a cylindrical shape using a heat-resistant non-melting fluororesin block body such as PTFE or modified PTFE, for example. An annular flange 4b having a thickness of, for example, 0.3 mm is projected outward from the lower portion.

  The flange 4b of the orifice portion 4 is welded to the lower end surface of the circular hole portion 1f of the upper housing 1 by laser light. That is, when the cylindrical body 4a of the orifice portion 4 is inserted into the circular hole portion 1f and irradiated with laser light from the flange 4b side, the upper housing 1 is softened and the flange 4b is welded to the upper housing 1. Thereby, the outflow pipe 1d and the empty chamber 1e are communicated with each other through the orifice portion 4.

  On the other hand, a circular hole portion 2c into which a shaft portion of a diaphragm portion 5 to be described later can be inserted is provided at the center of the substantially disc-shaped lower housing 2, and an annular base 2d is formed on the upper surface of the lower housing 2. Yes.

  A separate diaphragm portion 5 made of non-melting fluororesin having heat resistance such as PTFE similar to the orifice portion 4 and formed by grinding is fixed to the lower portion of the upper housing 1. A shaft portion 5a is provided at the central portion of the diaphragm portion 5, and a needle-like or conical valve body 5b inserted into the cylindrical body 4a of the orifice portion 4 projects upward on the shaft portion 5a. For example, a diaphragm film 5c having a thickness of 0.3 mm is formed around the shaft portion 5a, and an annular flange 5d having a thickness of about 0.5 mm is formed around the diaphragm film 5c. Moreover, the connection part 5e with which the drive shaft of the drive part 20 connects is provided in the lower part of the shaft part 5a.

  When the flange 5d of the diaphragm portion 5 is fitted into the recess 1h of the upper housing 1 and laser light is irradiated from the flange 5d side, the upper housing 1 is softened and the flange 5d is welded to the upper housing 1.

  When the flange 5d of the diaphragm portion 5 is welded to the upper housing 1, the empty chamber 1e of the upper housing 1 is sealed from the lower side. Thereby, the fluid flowing in from the inflow pipe 1c reaches the empty chamber 1e through the passage 1g, and further reaches the outflow pipe 1d through the orifice portion 4.

  When the diaphragm portion 5 is bonded to the upper housing 1 and a vertical force is applied to the shaft portion 5a of the diaphragm portion 5, the shaft portion 5a is supported by the diaphragm film 5c and can move up and down, and the valve portion 5b moves up and down. It will be.

  An attachment portion 22 for fixing the flow control valve 10 is provided on the upper portion of the housing 21 of the drive portion 20. A driving means, for example, a stepping motor 23 is built in the casing 21, and a driving shaft 24 connected to the rotating shaft of the stepping motor 23 projects upward. A connecting tool 25 for connecting to the connecting portion 5 e of the diaphragm portion 5 is attached to the tip of the drive shaft 24. The mounting portion 22 is provided with a plurality of screw holes 26 into which the bolts 3 are screwed.

  The above-mentioned adhesion to the upper housing 1 of the flange 4b of the orifice portion 4 and the flange 5d of the diaphragm portion 5 is performed by, for example, heating laser light generated from a carbon dioxide laser light source while pressing the flange 4b and flange 5d against the upper housing 1. Is irradiated in a ring shape by scanning a plurality of times if necessary.

  When the upper housing 1 made of a thermoplastic fluororesin is heated to, for example, about 320 ° C. or more by irradiation with the laser beam for heating, melting starts, and the flanges 4 b and 5 d of the orifice portion 4 and the diaphragm portion 5 are attached to the upper housing 1. Bonded in an annular shape. The scanning of the laser beam may be performed by rotating the laser light source or rotating the jig that fixes the upper housing 1 as long as relative scanning is possible.

  The flange 4b of the orifice part 4 and the flange 5d of the diaphragm part 5 may be bonded to the upper housing 1 by ultrasonic welding rather than by laser light.

  When the upper housing 1 is overlaid on the lower housing 2 and the bolts 3 are inserted and tightened into the insertion holes 1b and 2b of the flanges 1a and 2a, the bolts 3 are screwed into the screw holes 26 of the mounting portion 22 of the drive unit 20. The upper housing 1 and the lower housing 2 are fixed to the mounting portion 22. At this time, since the pedestal 2d of the lower housing 2 is in contact with the flange 5d of the diaphragm portion 5 in an annular shape, the flange 5d of the diaphragm portion 5 is sandwiched between the upper housing 1 and the lower housing 2, and adhesion is further ensured.

  In this process, the drive shaft 24 of the stepping motor 23 is coupled to the coupling portion 5e of the diaphragm portion 5 via the coupling tool 25. When the drive shaft 24 is moved up and down by the rotation of the stepping motor 23, the shaft portion 5a of the diaphragm portion 5 moves up and down while deforming the diaphragm film 5c. As a result, the vertical position of the conical valve body 5b inserted in the cylindrical body 4a of the orifice section 4 with respect to the orifice section 4 is adjusted, and the fluid passage cross-sectional area in the cylindrical body 4a changes to control the fluid flow rate. The Further, when the shaft portion 5a is raised and the valve body 5b is sufficiently inserted into the cylindrical body 4a, the fluid is blocked by the valve portion including the orifice portion 4 and the valve body 5b.

  In actual use, a pair of pipes made of, for example, PFA is connected to the inflow pipe 1c and the outflow pipe 1d of the housing 1 by heat welding or the like.

  Further, when the flow control valve 10 having different valve characteristics is manufactured, the orifice portion 4 having different dimensions and shapes can be manufactured, and can be assembled to the upper housing 1 which can be easily manufactured by thermoforming such as injection molding. The cost is low and the manufacture is easy.

  Further, the lower housing 1 can be fixed to the lower housing 1 by molding the lower housing 1 with a thermoplastic fluororesin so as to surround the orifice portion 4 that has been ground in advance when the lower housing 1 is injection-molded.

  Thus, by using a heat-resistant resin only for the orifice part 4 and the diaphragm part 5 corresponding to the vicinity of the valve part of the diaphragm type flow control valve and using a resin obtained by thermoforming the other parts, the valve part by the high temperature fluid The deformation of the neighborhood is prevented. For this reason, it is possible to control the high-temperature fluid flow rate with high accuracy and to manufacture a diaphragm flow control valve at low cost.

  In the embodiment, for convenience of explanation, the vertical direction and the horizontal direction have been described according to the drawings. However, the actual product may be different from the vertical direction and the horizontal direction.

DESCRIPTION OF SYMBOLS 10 Flow control valve 1 Upper housing 1a, 2a, 4b, 5d Flange 1c Inflow pipe 1d Outflow pipe 1e Empty room 1g Passage 2 Lower housing 3 Bolt 4 Orifice part 4a Cylindrical body 5 Diaphragm part 5a Shaft part 5b Valve body 5c Diaphragm membrane 5e Connecting unit 20 Drive unit 23 Stepping motor 24 Drive shaft

Claims (8)

A control unit comprising a housing to which a pair of pipe bodies can be connected, a cylindrical orifice portion fixed to the housing, and a valve body inserted into the orifice portion, and fixed to the housing. The fluid is a diaphragm type flow control valve from one of the pipes to the other pipe through the orifice part and the valve body,
The diaphragm type flow control valve according to claim 1, wherein the housing is made of thermoformed resin, and the orifice part and the diaphragm part are made of heat resistant resin.   2. The diaphragm type flow control valve according to claim 1, wherein each of the orifice part and the diaphragm part has a flange, and these flanges are welded to the housing.   The diaphragm type flow control valve according to claim 2, wherein the flange of the diaphragm portion is sandwiched by the bisected housing.   The diaphragm type flow control valve according to claim 1, wherein the orifice portion molded in advance is fixed to the housing at the time of injection molding of the housing.   The diaphragm type flow control valve according to any one of claims 1 to 4, wherein the orifice part and the diaphragm part are manufactured by cutting a non-melting fluororesin as a raw material.   The diaphragm type flow control valve according to claim 5, wherein the non-melting fluororesin is PTFE or modified PTFE.   The diaphragm type flow control valve according to claim 1, wherein the resin of the housing is a thermoplastic fluororesin.   The diaphragm type flow control valve according to any one of claims 1 to 7, wherein the valve body provided in the diaphragm portion has a needle shape.

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