JP3073177B2 - Flow control valve and valve stem - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve and its valve stem, and more particularly to a magnetic coupling type flow control valve and its valve stem.

[0002]

2. Description of the Related Art In the manufacture of parts for electronic application equipment such as semiconductor integrated circuits and liquid crystal displays, chemicals using a chemically active chemical such as an aqueous solution of hydrogen fluoride (hydrofluoric acid) or hydrochloric acid are used. There is a typical processing step.

[0003] It is essential that the chemical solution used in such a processing step has a high purity. In particular, even a small amount of metal ions may have a fatal effect on the product rejection rate even in a very small amount. Even if a metal has high resistance to the chemical, it must be avoided that the metal comes into direct contact with the chemical solution.

Therefore, a material and a structure in which contamination of the chemical solution by foreign substances, particularly, metal ions, which are eluted or mixed with the chemical solution, are as small as possible are used for a liquid contact portion of the apparatus used in this processing step which comes into contact with the chemical solution. Currently, most of the wetted parts are PTFE (polytetrafluoroethylene), PF
A (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) or other fluororesin that has low contamination and high chemical resistance is used.

On the other hand, since the chemical solution used in this treatment step, particularly hydrofluoric acid, has small molecules and high permeability, some molecules pass through between the molecules of the fluororesin structure to become a gas. Leakage, and if there is a component with low chemical resistance outside, it may corrode and lose its function.

[0006] As described above, devices and parts used in the chemical treatment process in the manufacture of parts for electronic applications such as semiconductor integrated circuits and liquid crystal displays have liquid contact parts made of PTFE or P.
A structure that is made of a fluororesin such as FA and that does not impair the function due to the permeation of the drug solution molecules and does not cause contamination of the drug solution is required.

In the above-mentioned chemical treatment process, various flow control valves are used for controlling or controlling the flow rate of the chemical solution, and these types of flow control valves have a so-called magnetic coupling for displacing a valve stem by magnetic coupling. There is a type flow control valve.

In this type of flow control valve, the tip of a valve stem enters a valve hole of a valve seat in a flow passage, and the fluid passage area of the valve hole is adjusted by adjusting the axial movement of the valve stem. Is set to adjust the flow rate.

In the case of a flow control valve, the valve body, the lead pipe surrounding the valve rod, and the valve rod are made of PFA or PTFE, so that the material of the liquid contact part can meet the requirements, but is widely used for general purposes. In the flow control valve, the valve stem contains a magnet.

[0010] In the magnetic coupling type flow control valve of the valve rod with a built-in magnet, since no mechanical connection such as a shaft and a rod is required between the valve rod and a mechanism for driving the valve, the flow path is formed by a partition wall. One of the major features is that it can be sealed and completely sealed.

However, in this type of flow control valve, a chemical solution penetrates into a valve stem made of fluororesin such as PTFE or PFA, and the inside magnet is corroded, so that the valve stem cannot withstand long-term use. There is.

No flow control valve other than the magnetic coupling type can satisfy all the conditions such as contamination of liquid contact material and chemicals, dust generation during operation, and long-term durability. There is a demand for a flow control valve that can be used for a long period of time for acids and the like.

[0013]

An object of the present invention is to provide a valve stem which is provided with a magnet inside, and which is not corroded by a chemical passing through a flow control valve and does not contaminate the chemical. An object of the present invention is to provide a flow control valve and a valve stem thereof, which are provided and satisfy the conditions for use in manufacturing equipment for parts for electronic application equipment such as a semiconductor integrated circuit and a liquid crystal display.

[0014]

In the flow control valve according to the present invention, an inflow passage and an outflow passage are formed in a valve body, a valve seat is provided in the flow passage, and one end faces a valve hole of the valve seat. In addition, the other end is provided with a valve stem having a built-in magnet, and a portion of the valve stem protruding from the valve box body is surrounded by a lead pipe having an outer end closed provided in the valve box body. Drive that can be linearly moved forward and backward by forward and reverse drive of the motor provided outside the lead pipe
Magnetically coupled with the driving magnet as a magnetic force generator provided on the body
In a magnetic coupling type flow control valve that is linearly moved to adjust the opening of a valve seat, the valve body, the valve seat, the valve stem and the lead pipe are made of a fluororesin, and the valve stem is made chemically resistant. It has a built-in magnet shielded by a non-magnetic metal case.

In another example, a flow path of an inflow path and an outflow path is formed in a valve body, a valve seat is provided in the flow path, one end faces a valve hole of the valve seat, and the other end is formed. The valve stem has a built-in magnet, and the portion of the valve stem protruding from the valve box body is surrounded by a lead pipe that is closed at the outer end provided on the valve box body, and the built-in magnet of the valve stem is provided outside the lead pipe. Magnetic generator
In a magnetic coupling type flow control valve, which is held by being magnetically coupled with a magnetic force generated by a barrel coil and adjusts an opening of a valve seat, a valve box body, a valve seat, a valve rod, and a lead pipe are made of fluororesin, In addition, the valve stem is configured to have a built-in magnet which is made chemical resistant and shielded by a non-magnetic metal case.

Further, the valve stem according to the present invention is made of a fluororesin.
Made of non-magnetic metal case
It has a configuration that incorporates a built-in magnet.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a first embodiment of a vertical flow rate control valve according to the present invention, in which reference numeral A denotes a valve box, which comprises a valve box body 1 and a valve box cover 2, wherein the valve box cover has a cylindrical body having an upper plate. It consists of.

An inflow passage 3a and an outflow passage 3b communicate with the valve body via a valve seat 4, and reference numeral 5 denotes a valve hole of the valve seat. At the upper part of the valve box main body, there is provided a lead pipe 6 whose upper end is closed, which covers a portion of the valve stem protruding into the valve box lid. It is a partition body that defines the inside.

A drive magnet 8 is provided around the lead pipe 6 as a magnetic force generator attached to an elevating mechanism (linear motion mechanism) which is moved up and down by forward and reverse rotations of a motor 7 provided above the valve box lid. It is.

The elevating guide mechanism includes an elevating body 9 which is a top-moving cylindrical linear motion driving body having the ring-shaped driving magnet 8 at a lower portion, and a vertical guide 11 provided on a top flange 10 of the elevating body. A vertical guide rod 12 for stopping and a lifting body 9
The guide rod 12 has an upper end fixed to the lower surface of the top plate of the valve box cover, and the screw shaft 14 is driven by the motor 7. .

Numeral 15 denotes a valve stem, in which a magnet 16 is built in the upper part. The magnet 16 is magnetically coupled with the driving magnet 8 of the elevating body so that the lower end faces the hole 5 of the valve seat 4 so that the magnetic force of the driving magnet can be obtained. Is held by

In the above construction, the present invention provides a valve box main body, a valve seat, a lead pipe, and a valve stem which are made of chemical-resistant PFA or PTFE.
The magnet 16 in the valve stem is not provided directly in the valve stem, but is provided in the valve stem by making the magnet 16 chemically resistant and shielded with a non-magnetic metal. Reference numeral 17 denotes the shield case.

In this embodiment, the elevating body 9 is moved up and down by rotating the motor 7 forward and backward. That is, since the elevating body 9 is stopped by the guide rod 12 passing through the guide 11 opened on the flange 10, when the screw shaft 14 rotates forward and reverse by the forward and reverse driving of the motor 7, the elevating body 9 is vertically moved by the nut 13. The follower magnet in the valve stem, which is screw-fed and magnetically coupled to the drive magnet 18 of the elevating body, causes
5 also moves up and down to adjust the fluid passage area (opening) of the valve hole.

FIG. 2 shows a second embodiment of the vertical type in which the motor 7 is supported by a column 19 erected on the valve body.
Reference numeral 20 denotes a mounting plate or a flange of a motor passed between the columns.

FIG. 3 shows a third embodiment of the vertical type according to the present invention.
The only difference is that the valve rod driving means is different from those of the first and second embodiments. In this embodiment, a ring-shaped coil 18 as a magnetic force generator is provided around the lead pipe 6, and the fluid passage area of the valve hole 5 is adjusted by controlling the strength of the current flowing through the ring-shaped coil. There are things.

The ring-shaped coil 18 is designed to form a magnetic flux in the direction of pushing down the magnet in the valve stem when a current flows, and when the current is increased, the valve stem 15 faces downward, that is, the valve hole 5 is formed. The force works in the closing direction. On the other hand, a force acts on the valve rod 15 in an upward direction, that is, in a direction in which the valve hole 5 is opened, by the pressure of the fluid passing through the valve hole 5 from below.

The force for pushing up the valve stem due to the pressure of the fluid passing through the valve hole 5 and the force for lowering the valve stem by the ring-shaped coil 18 are balanced by adjusting the strength of the current flowing through the ring-shaped coil 18. When the flow rate of the liquid is increased, the current flowing through the ring-shaped coil 18 is reduced. When the flow rate of the liquid is reduced, the current flowing through the ring-shaped coil is increased. The valve stem in the third embodiment is also provided inside the valve stem with a magnet made chemical resistant and shielded by a nonmagnetic metal case 17.

The above description shows a vertical flow control valve, but there is also a horizontal flow control valve as in the fourth embodiment shown in FIG. In the second to fourth embodiments, the valve box cover 2 is not necessarily required.

[0029]

In the flow rate control valve shown in each of the above embodiments, the metal shield case 17 prevents the corrosion component of the chemical solution penetrating the fluororesin valve stem such as PFA or PTFE from coming into contact with the magnet. Therefore, the magnet does not corrode even in long-term use.

On the other hand, impurities contained in the metal are eluted from the outer wall of the shield case 17 made of metal into the components of the chemical solution that have passed through the fluororesin of the valve stem. Therefore, metal ions and impurities from the metal shield case 17 are not eluted or mixed into the chemical solution passing through the flow path, and the chemical solution is not contaminated.

Since the metal shield case is made of a non-magnetic material, it does not interfere with the lines of magnetic force generated by the magnet and does not adversely affect the operation of the flow rate control valve of the magnetic coupling type.

The metal, which withstands the components of the chemical solution that penetrates the fluororesin of the valve stem and is a non-magnetic material, has the type, concentration,
You can select a suitable one depending on the operating temperature, etc.
Hastelloy C, a nickel-chromium-molybdenum alloy, is preferred as being the most corrosive and capable of resisting hydrofluoric acid, which is easily permeable to fluorocarbon resins. In addition to Hastelloy C, lead, K monel, Hastelloy B, and the like can also be used depending on the concentration and the operating temperature, and the cost does not increase significantly.

The inventor of the present invention immersed a sample of a valve stem having PFA as a valve stem and a metal shield case 17 made of Hastelloy C and having an outer diameter of 22 mm as shown in FIG. As a result, it was confirmed that the Hastelloy C container was not corroded at all, the metal ions of Hastelloy C were not eluted in hydrofluoric acid, and the chemical solution was not contaminated.

From this experimental result, in the valve stem of the above-mentioned size according to the present invention, the thickness of the shield case built-in portion of the valve stem can be about 2 mm, the thickness of the metal shield case can be about 1 mm, and the volume inside the valve stem can be reduced. It is possible to provide a flow control valve in which a magnet having a large diameter can be provided and the magnetic coupling force is large, so that the valve stem can be operated accurately.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a vertical flow control valve according to the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the vertical flow control valve according to the present invention.

FIG. 3 is a longitudinal sectional view showing a third embodiment of a vertical flow control valve according to the present invention.

FIG. 4 is a longitudinal sectional view showing a fourth embodiment of the horizontal flow control valve according to the present invention.

FIG. 5 is a longitudinal sectional view of a valve stem used in the flow control valve of the present invention.

FIG. 6 is a partial longitudinal sectional view showing a sample of a valve stem used for the flow control valve of the present invention.

[Explanation of symbols]

 A: Valve case 1 ... Valve case body 2 ... Valve case cover 3a ... Inflow path 3b ... Outflow path 4 ... Valve seat 5 ... Valve hole 6 ... Lead pipe 7 ... Motor 8 ... Driving magnet as a magnetic force generator 9 ... Elevating body as a linear motion mechanism 10 ... Flange 11 ... Guide hole 12 ... Guide rod 13 ... Nut 14 ... -Screw shaft 15-Valve stem 16-Magnet 17-Shield case 18-Coil that is a magnetic force generator 19-Prop 20-Mounting plate

Continuation of front page (72) Inventor Tokio Sugi 1-7-24 Shiba Park, Minato-ku, Tokyo Inside Tokyo Keiso Co., Ltd. (56) References JP-A-2-129485 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) F16K 31/04 F16K 31/06

Claims (3)

(57) [Claims] An inflow passage and an outflow passage are formed in a valve body, a valve seat is provided in the flow passage, one end faces a valve hole of the valve seat, and a magnet is built in the other end. A portion of the valve stem protruding from the valve box body is surrounded by a lead pipe closed at the outer end provided on the valve box body. In a magnet-coupling type flow control valve, which is magnetically coupled with a driving magnet as a magnetic force generator provided in a driving body that is linearly moved forward and reverse by reverse driving and is linearly moved forward and reverse to adjust the opening of a valve seat, a valve box is provided. A flow control valve with a main body, valve seat, valve stem and lead pipe made of fluororesin, and a valve stem with a built-in magnet that is chemically resistant and shielded by a nonmagnetic metal case . 2. An inflow passage and an outflow passage are formed in a valve body, a valve seat is provided in the flow passage, one end faces a valve hole of the valve seat, and a magnet is built in the other end. A portion of the valve stem protruding from the valve box body is surrounded by a lead pipe with an outer end closed provided on the valve box body, and the valve stem has a built-in magnet whose magnetic force is generated outside the lead pipe. In a magnetic coupling type flow control valve that is magnetically coupled with a magnetic force generated by a body coil and is held and adjusts an opening of a valve seat, a valve body, a valve seat, a valve rod, and a lead pipe are made of a fluororesin. And a valve stem having a built-in magnet which is chemically resistant and is shielded by a non-magnetic metal case. 3. A valve stem made of a fluororesin and having a built-in magnet which is chemically resistant and is shielded by a nonmagnetic metal case.