JPH07110074A - Purge valve for container capable of making small flow rate purge - Google Patents

Abstract

PURPOSE:To enable the purge gas flow rate to be selected by providing a first diaphragm valve between an upper passage and a lower passage for introducing purge gas, providing a second diaphragm valve between a lower passage and a discharging passage, and providing a deep purging pipe on a joint member of a gas storage container to the gas discharging passage. CONSTITUTION:A metal diaphragm valve A is closed, and also a valve B is opened in the small flow rate purge, and purging inert gas is allowed to flow into a small flow rate purge gas introducing lower passage through a communication hole pipe, and the connecting work is performed while spraying a small quantity of gas to the root part of a gas storage container. After that, the valve of the gas storage container is closed, and the valves A, B are opened in the full-scale purge work, and a large quantity of gas is introduced from a purge gas introducing upper passage 4, and the gas is injected from an injection port through a purge gas introducing lower passage 5, a gas discharging passage 10 and a pipe 14 for deep purge of the joint member 3, and then the passage is purged by stirring the root part of the gas storage container and the inside of the communication passage 18. The gas passes a process gas discharging lower passage 12, so as to purge-treat the piping system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a purge valve for a gas storage container which is used by being attached to a gas storage container filled with a liquefied gas or a high pressure gas. The present invention relates to a container purge valve capable of performing a small flow rate purge.

[0002]

2. Description of the Related Art In recent years, ultra high purity gas has been used in various industrial fields. For example, there are gases used in semiconductor manufacturing processes, but the purity of these so-called process gases has a significant impact on the quality of the manufactured products.
Therefore, great care must be taken to maintain the high purity of the gas. Further, some of these process gases are highly toxic and have a high risk of exploding, and therefore safety is strongly required in handling. These process gases are once filled in a gas storage container and supplied through a main valve attached to this container.

The high-purity process gas described above is
It is used from a storage container through various valves and pipes via a main valve. At this time, if there are gases or particles containing impurities in the pipe, or more specifically, if impure gas is adsorbed on the metal surface in contact with the gas, these impure gases or particles are released when passing through the high-purity process gas. Reduce the purity of the high-purity process gas. In order to prevent this, for example, there is a measure that all the metal surfaces in contact with gas are subjected to electropolishing treatment with high precision and mirror-finished so that impure gas is not adsorbed to the metal surface as much as possible. Also, it is usually done to attach the main valve to the storage container, and before the high-purity process gas flows, vacuum the pipe system with a vacuum pump or perform a purge process by replacing with an inert gas to clean the inside of the pipe. Is being done.

For example, there is a joint having a purging mechanism as shown in FIG. This is a gas storage container with connection 74
It is connected to a main valve (not shown), and a purge gas tube 70 is introduced into the body portion 73 to a deep part near the connection portion 74. Alternatively, a process gas lead-out tube 71 is provided. Therefore, during the barge process, the purge process can be performed by introducing the barge gas from the purging tube 70 and including all the bases of the storage container and the pipe after the gas outlet tube 71.

[0005]

By the way, it is desirable that the operation of attaching the purge valve to the container, more specifically to the main valve of the container, is carried out while flowing the purge gas, and after the attachment, a full-scale purging operation is performed. However, in the above conventional example, since there is no valve mechanism, once the purge gas is made to flow, its flow rate is constantly constant. In other words, at the time of installation, a small amount of purge gas is sufficient, but a large amount of gas is kept flowing, which is very wasteful. On the other hand, after installation, it is more efficient to send a large amount of purge gas all at once, including inside the pipe, to perform purge. Even if the valve mechanism is installed in the piping system, the commercially available one is normally ON-OF.
It is an F valve, and there is only an operation of flowing or stopping the purge gas. That is, conventionally, there was no room to select the purge gas flow rate according to the work.

In addition to the metal diaphragm valve mechanism in which particles are not generated, the present invention enables a purge operation even in a small flow rate range and has a function of selecting either a small flow rate or a large flow rate as the purge gas flow rate depending on the situation. Another object of the present invention is to provide a purge valve for a gas storage container.

[0007]

According to the present invention, an upper flow path for introducing purge gas and a lower flow path for introducing purge gas are blocked by a partition wall, and the partition wall is provided with a communication hole through which a small flow rate passes. First metal diaphragm valve body which is in communication with the valve seat portion and directly seats on or separates from the valve seat portion, and the diaphragm provided on the diaphragm is pressed or released. The purge gas introduction lower flow path and the gas discharge flow path are blocked by a partition wall, and both flow paths communicate with each other via a second valve seat portion. A second metal diaphragm valve body which is directly seated on or separated from the second valve seat portion and a second operation means which is provided on the upper part of the diaphragm and presses or releases the diaphragm. Built-in valve body and passage inside , A connecting portion with a gas storage container at one end, the other end is a joint member connected to the gas outlet channel, is in the passage of the joint member, one end extends to near the connecting portion of the gas storage container, A small-flow purge is possible, which includes a deep purge pipe having the other end mounted in the gas outlet channel and a nut member attached to the joint member and connected to the gas storage container through the joint of the joint member. It is a purge valve for various containers.

[0008]

Since the partition wall between the upper flow path for introducing purge gas and the lower flow path for introducing purge gas has a communication hole, the purge gas always flows to the lower flow path side. Here, if the first valve seat portion is closed and the second valve seat portion is opened, that is, the first metal diaphragm valve is closed and the second metal diaphragm valve is opened, the small passage that passes through the communication hole can be achieved. Since only the flow rate of the purge gas is supplied to the gas outlet channel, it is suitable for purging when the container is replaced. On the other hand, if both the first and second metal diaphragm valves are opened, a large amount of purge gas flows from the main flow path connecting the purge gas introduction upper flow path to the gas discharge flow path, which is suitable for full-scale purging after container replacement. . As described above, it is possible to selectively use the large-flow purge operation and the small-flow purge operation.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are partial cross-sectional views of a gas storage container purge valve (hereinafter referred to as a purge valve) capable of performing a small flow rate purge according to an embodiment of the present invention. FIG. 1 shows a case where a small flow rate purge is performed, and FIG. 2 shows a case where a large flow rate purge is performed. In the figure, a valve having a first valve seat portion, a valve element, and an operating portion is a first metal diaphragm valve A, and a valve element having a second valve seat portion, a valve element, and an operating portion is a second metal. It is called diaphragm valve B. Note that the reference numerals in FIG. 2 are the same as those in FIG.

The structure of the purge valve will be described below. First, the valve body 1 integrally includes a first metal diaphragm valve A and a second metal diaphragm valve B in one valve box 2. First, the metal diaphragm valve A is the valve box 2
A substantially L-shaped purge gas introduction upper flow path 4 and a substantially inverted L-shaped purge gas introduction lower flow path 5 are formed therein, and these flow paths are blocked by a partition wall 6 but are located above the first valve seat. It communicates with the valve chamber in which the portion 7A is formed. A communication hole made of a small flow rate leak pipe described below is provided below the partition wall 6. A seal ring made of, for example, a fluororesin is fitted to the first valve seat portion 7A in order to improve the sealing property, and the first metal diaphragm valve body 8A is provided at a position facing the valve seat portion. The diaphragm holding member is placed so that the outer circumference is tightly attached. Further, on the upper part thereof, there is provided a first operating means 9A for generating a load for seating or separating the diaphragm valve body on the valve seat. This operating means is preferably an air cylinder type actuator as in the present embodiment, but may be a manually operated valve or a solenoid valve.

The metal diaphragm valve B will be briefly described below. The purge gas introduction lower flow path 5 is formed continuously and is blocked by the gas discharge flow path 10 and the partition wall 11, but the second valve seat portion is formed. It communicates with 7B. A stepped hole portion 13 is formed in the middle of the gas outlet channel 10, and a deep purge pipe described below is attached to the stepped hole portion 13. On the downstream side, a process gas outlet lower flow path 12 is formed, which is branched and connected at a 90 ° angle. This flow path serves as a process gas outlet flow path when the process gas in the storage container is allowed to flow after the purging process. Others are the same as those of the metal diaphragm valve A described above, and therefore the following description will be omitted.

The above-mentioned theta diaphragm valve bodies 8A and 8B may be laminated on a plurality of thin stainless steel plates. Further, gold plating may be applied between the diaphragms to improve lubricity and galling prevention. The shape of the diaphragm is a so-called partial spherical shell shape in which the outer peripheral edge is flat and the central portion bulges upward. Therefore, when the bulging central portion is pressed by the load means, the diaphragm valve body undergoes a snapping deformation within the elastic deformation region under a certain constant load, and becomes a seated state in which the diaphragm valve body is in direct contact with the valve seat, and the valve is closed. .
Then, when the load means is moved upward, the diaphragm valve body returns to its original state due to its elastic restoring force, and the valve is opened.

In the valve body described above, the inner surfaces of the valve chamber, the purge gas introducing upper flow path 4, the purge gas introducing lower flow path 5 and the gas derivation lower flow path 10 are individually electropolished to prevent gas adsorption. The surface is finished. Moreover, the gas-contacting portion in the valve chamber has only a metal diaphragm valve body, is extremely simple, has a small dead space, and has no particle generation source.

Next, the communication hole provided in the metal diaphragm valve A will be described. The partition wall 6 will be provided with a communication hole having an inner diameter of approximately 0.2 to 1.0 mm. However, since such a small diameter hole is difficult to process, if it cannot be directly formed in the partition wall,
A stainless steel pipe can be used as in this embodiment.
That is, the pipe 16 having a small inner diameter is once fixed to the holder member 17 by brazing or the like, and the holder member with a pipe is press-fitted into a relatively large-diameter fitting hole formed in the partition wall for easy processing. This is convenient because the leak flow rate can be easily manipulated by appropriately selecting the diameter and length of the pipe.

The joint member 3 has a communication passage 18 formed therein, and the inner surface of the joint member 3 is electropolished similarly to the valve box 2. One end of the joint member 3 is fixed to the valve box 2 by welding means in a state where the deep purge pipe 14 extends to the inner part of the communication passage 18. On the other hand, a connection portion 19 with a gas storage container (not shown) is formed at the other end, and a nut member 30 is provided outside the connection portion 19 via a bearing 20. Therefore, the screw and the male thread on the container side are screwed together to be provided on the inner peripheral surface of the nut member 30 to connect the purge valve and the gas storage container.

The deep purge pipe 14 is made of stainless steel like the above-mentioned leak pipe, and is electrolytically polished. The ring member 1 is attached to one end of the pipe 14.
5a is attached by brazing or the like, and the thin pipe with the annular member is inserted into the step gas hole 13 formed on the inner side of the process gas discharge lower flow path 12 in the purge gas discharge flow path 10 and then caulked. Pipe 1 by caulking member 15b
4 is fixed in the flow path.

Next, the operation of the gas storage container purge valve will be described. First, when connecting the purge valve to the main valve of the gas storage container by using the nut member 30, that is, when purging at a small flow rate, the metal diaphragm valve A is closed as shown in FIG. The diaphragm valve B is opened to allow an inert gas for purging, such as N ₂ gas, to flow to the lower flow path side by a small flow rate through the communication hole pipe, and a small amount of purge gas is supplied to the base portion including the connecting portion of the gas storage container. Perform connection work while spraying. afterwards,
When performing a full-scale purging operation by closing the valve installed in the gas storage container itself, as shown in FIG. 2, both metal diaphragm valves A and B are opened, and a large amount of N ₂ gas is introduced from the purge gas introduction upper flow path. Then, N ₂ gas is ejected from the ejection port at the tip through the purging gas introduction lower channel 5, the gas derivation channel 10, and the deep purging pipe 14 to stir the root portion of the gas storage container and the inside of the communication passage 18. The entire wall including the peripheral wall of the passage is purged. Then, the N ₂ gas passes through the process gas outlet / lower channel 12 to purge the subsequent piping system. After the purging process, the metal diaphragm valve B is closed and the main valve of the gas storage container is opened to allow the process gas to flow through the process gas outlet / lower flow path 12.

As described above, the purge valve of this embodiment can supply a small flow rate and a large flow rate of the purge gas, and can be used properly according to the situation, so that the waste of the purge gas can be reduced. In addition, since the flow path in the valve device, the narrow tube, and the gas contacting portion of the joint member can be individually and easily subjected to electrolytic polishing and then assembled, gas adsorption is small and particles are not generated. Moreover, since the two valves are integrated into one valve box, the dead space is small and the size is compact.

[0017]

EFFECTS OF THE INVENTION According to the present invention, a compact valve structure with less gas adsorption, generation of particles, and less dead space, and a purge gas supply of a small flow rate and a large flow rate is selected and the root of the storage container is selected. Complete and efficient purging can be performed even in deep places.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a purge valve according to the present invention during a small flow rate purge.

FIG. 2 is a cross-sectional view of an essential part showing a purge valve of the present invention during a large flow rate purge.

FIG. 3 is a piping diagram of a joint portion showing a conventional purging mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Valve main body 2 ... Valve box 3 ... Joint member 4 ... Purge gas introduction upper flow path 5 ... Purge gas introduction lower flow path 6, 11 ... Partition wall 7A ... 1st valve seat part 7B ... 2nd valve seat part 8A ... 1st Metal diaphragm valve body 8B ... Second metal diaphragm valve body 9A ... First operating means 9B ... Second operating means 10 ... Gas outlet passage 12 ... Process gas outlet passage 14 ... Depurge pipe 16 ... Small flow purge Pipe 18 ... Gas passage 19 ... Connection part 30 ... Nut member

Claims (1)

[Claims] 1. An upper flow path for introducing purge gas and a lower flow path for introducing purge gas are blocked by a partition wall, and the partition wall is provided with a communication hole through which a small flow rate passes, and both flow paths communicate with each other through a first valve seat portion. And a first metal diaphragm valve body which is seated or separated from the valve seat portion, and a first operation means which is provided on the diaphragm and presses or releases the diaphragm. At the same time, the purging gas introduction lower flow path and the gas derivation flow path are blocked by a partition wall, and both flow paths communicate with each other through a second valve seat portion, and directly to the second valve seat portion, A valve body integrally provided with a second metallic diaphragm valve body for seating or separating and a second operating means provided on the upper part of the diaphragm for pressing or releasing the diaphragm, and It has a passage and a gas storage container at one end A joint member having a connecting portion, the other end of which is in the passage of the joint member, and the other end of which is connected to the gas outlet passage, one end of which extends to the vicinity of the connecting portion of the gas storage container and the other end of which is the gas outlet passage A container capable of purging at a small flow rate, which comprises a deep purging pipe attached inside and a nut member attached to the joint member and connected to a gas storage container through a connecting portion of the joint member. Purge valve.