Container valve

A container valve, attached to a gas container, wherein the container valve has a pressure reducing function, and is inside a valve block in the gas container. In the valve block, the container valve comprises a gas filling passage in which a filling valve is installed, a gas lead-out passage in which a lead-out valve is installed, and a pressure regulator arranged at an upstream side of the lead-out valve in the gas lead-out passage. The container valve can safely supply gas under a reduced pressure for use by opening the container valve of a container whose pressure is high and gas can be filled easily into the container. The container valve can be miniaturized and the purging operation for supplying high purity gas can be performed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Japanese application serial No. 2001-367045, filed on Nov. 30, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates in general to a container valve with pressure reducing function, and more specifically relates to a valve with a structure suitable for a gas container filled with various gases that have the characteristics of being inflammable, spontaneous-flammable, and toxic, corrosive and combustible-supportability.

2. Description of Related Art

Gas used in industry (industrial gas) is often high-pressure gas having dangerous characteristics such as being inflammable, spontaneous-flammable, and toxic, corrosive and combustible-supportability. The gas is supplied to and consumed by consumption equipment. This makes it difficult to maintain safety. Especially in the semiconductor industry, the larger the diameter of a wafer is, the more semiconductor gas with dangerous characteristics consumed. Still severer management must be increasingly performed to maintain safety.

Generally, the method for supplying industrial gas is as follows. The gas is filled into a high-pressure container under high pressure. A pressure regulator is arranged on the gas supplying line. The gas with high-pressure is reduced to a specific consumption pressure (1 Mpa or less is usual) by the pressure regulator. In the High-Pressure Gas Safety Law in Japan, the necessary techniques for using special high-pressure semiconductor gas such as silane, disilane, arsine, phosphine, diborane, hydrogen selenide and germane are stipulated in detail. Even though the consumption thereof is little, the consumption must be registered to the prefectural governor. Especially, parts in the high-pressure portion inside the cylinder cabinet must use the parts authorized by the High-Pressure Gas Safety Institute of Japan, wherein the high-pressure portion is from the connection portion of the container to the pressure regulator. There are two drawbacks: high danger with gas leakage due to the existence of the high-pressure portion and high cost due to using the authorized parts.

On the other hand, sometimes an adsorbent like zeolite or active carbon is filled into the container. The adsorbent absorbs the liquefied gas under pressure lower than the atmospheric pressure, wherein the liquefied gas is like phosphine, arsine, diborane and germane etc. The technique for supplying gas under this condition is practiced where the filling amount is seven to forty times compared with a container with the same volume for filling high-pressure gas without absorbent. Although the technique has great merit in terms of filling amount, it also has the problem that the gas cannot be supplied unless the pressure of consumption equipment is 10 or less than 10 Torr. This technique can only be used in the semiconductor industry using ion implantation or high-density plasma CVD etc. Furthermore, because the absorbent is used, it is difficult to remove the atmospheric impurity absorbed by the adsorbent. Additionally, because the adsorbent is also the source for generating particles, high purity gas cannot be provided.

A container which can supply gas under low-pressure is proposed referring to the Japan Laid-open publication no. 2001-510546, wherein a highly integrally formed pressure regulator and container valve are attached to the container. Since this container is not functional to efficiently fill the container with gas, because it is difficult to exhaust the container into a vacuum state before filling the gas and the filling speed is slow. As a result, the filled gas is of low purity. Furthermore, the remaining amount of gas cannot be managed with the low-pressure inside the container.

SUMMARY OF THE INVENTION

Here, an objective of this invention is to provide a container valve that can safely supply gas under reduced pressure when opening the container valve wherein the pressure inside the container remains high.

Another objective of this invention is to provide a container valve in which gas can be filled easily.

Another objective of this invention is to provide a container valve that can be made miniaturized.

Another objective of this invention is to provide a container valve with a pressure reducing function that can perform a purging operation for supplying high purity gas.

For achieving the objectives mentioned above, a container valve of the present invention is provided. The container valve is attached to a gas container, wherein the container valve has a pressure reducing function, and is inside a valve block in the gas container. The container valve in the valve block comprises a gas filling passage in which a filling valve is installed, a gas lead-out passage in which a lead-out valve is installed, and a pressure regulator arranged at an upstream side of the lead-out valve in the gas lead-out passage. Moreover, at least one of a safety relief valve and a pressure sensor is equipped to connect a downstream side of the filling valve in the gas filling passage. A filter is arranged at least either at an upstream side or a downstream side of the pressure regulator in the gas lead-out passage. A gas purifier is arranged at an upstream side of the pressure regulator in the gas lead-out passage. Furthermore, a check valve is arranged at an upstream side of the gas purifier.

The gas mentioned above is filled into a gas container made from stainless steel, CrMo steel, carbon steel, Mn steel, Al alloy and Al lining strengthened plastic etc. It is preferred to use a cylinder whose outer diameter is greater than 50 mm and less than 1200 mm and whose length is greater than 350 mm and less than 12000 mm as the gas container. Two ends of the gas container are hot formed into a plate or concave shape. The container valve installation portion is formed onto at least one of the two ends of the container. The container valve installation portion uses a screw process so that the container valve can be installed into the gas container.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1is a system diagram of the container valve with pressure reducing function according to the first embodiment of the present invention. The container valve11with pressure reducing function attached to a gas container10comprises a gas filling passage14in which a stop valve (filling valve)13is installed, a gas lead-out passage16in which a stop valve (lead-out valve)15is installed and a regulator17. The gas filling passage14and the gas lead-out passage16are set inside a valve block12installed onto the gas container10. The pressure regulator17is set on the upstream side (front section) of the lead-out valve15in the gas lead-out passage16. The gas filling passage14communicates with the gas phase10ainside the container through a gas filling outlet14a. A filling gas inlet14band the gas phase10aare separated by the filling valve13Moreover, the gas lead-out passage16communicates with the gas phase10ainside the container through a gas lead-out inlet16a. A gas lead-out outlet16band the gas phase10aare separated by the lead-out valve15.

When the lead-out valve15is opened, the high-pressure gas filled inside the gas container10flows into the gas lead-out passage16through the gas lead-out inlet16a. The pressure of the gas is reduced to a specific pressure by the pressure regulator17, wherein the specific pressure is set in advance. After that, the gas passes through the lead-out valve15and the gas is supplied to objects for consumption through the lead-out gas outlet16. Therefore, under the condition that the lead-out valve15is open, the gas whose pressure is reduced to a specific pressure is led out through the container valve11with pressure reducing function. Even though the lead-out valve15is opened carelessly, the gas is not strongly sprayed with high pressure as with the conventional one. The container valve of the present invention can provide higher safety. Furthermore, the container valve can be miniaturized by making these elements integrate.

The container valve11with pressure reducing function as shown in this embodiment is generally installed into one of the valve installation portions of the gas container, wherein the gas container has two locations for valve installation portions. A safety relief valve or a container valve having a safety relief valve is installed into the other one of the valve installation portions.

FIG. 2is a system diagram showing a container valve with pressure reducing function according to the second embodiment of the present invention. In the following description, for the same elements in the container valve with pressure reducing function mentioned in each embodiment with the same numerical references the explanation thereof is omitted.

In the container valve21with pressure reducing function as shown in this embodiment, a safety relief valve22is connected between the downstream side (rear section) of the filling valve13in the gas filling passage14and the gas filling outlet14a.

The container valve21integrated with the safety relief valve22also can be installed onto the gas container that has only one location for container valve installation.

Additionally, in the container valve21with pressure reducing function shown in this embodiment, a pressure sensor23is also connected to the downstream side of the filling valve13in the gas filling passage14. The pressure sensor23connects with the gas phase10ainside the container through the gas filling outlet14aso that the pressure of the gas phase10ainside the container can be detected. By integrally assembling the pressure sensor23into the container valve21, the rest of gas pressure inside the container can be managed and the timing for exchanging the container can be exactly known.

Moreover, similar to the first embodiment, in the gas container wherein a safety relief valve or a container valve having a safety relief valve is assembled in the other one of the container valve installation portions, the safety relief valve22can be omitted so that only the pressure sensor23is set. If there is no need to manage the pressure of the gas left over after use or the pressure sensor is set onto the other one of the container valve installation portions, the pressure sensor23can also be omitted.

Additionally, in the container valve21with pressure reducing function as shown in this embodiment, a filter24is assembled between the upstream side of the pressure regulator17in the gas lead-out passage16and the gas lead-out inlet16a. With this structure, by setting the filter24into the upstream side of the pressure regulator17, the gas leakage in the valve seat (seat leakage) of the pressure regulator17due to particles within the gas can be prevented.

FIG. 3is a system diagram showing a container valve with pressure reducing function according to the third embodiment of the present invention. In the container valve31with pressure reducing function as shown in this embodiment, the filter25is assembled onto the downstream side of the pressure regulator17in the gas lead-out passage16and the upstream side of the lead-out valve15. By setting the filter25onto this position, the particle inside the gas supplied to objects for consumption through the gas lead-out passage16can be removed.

FIG. 4is a system diagram showing a container valve with pressure reducing function according to the fourth embodiment of the present invention. In the container valve41with pressure reducing function as shown in this embodiment, the filters24,25are respectively assembled onto the upstream and the downstream sides of the pressure regulator17in the gas lead-out passage16. By respectively setting the filters24,25onto two locations, the seat leakage of the pressure regulator17can be prevented. The gas can be supplied for use in high purity with the particles removed.

FIG. 5is a system diagram showing a container valve with pressure reducing function according the fifth embodiment of the present invention. In the container valve51with pressure reducing function as shown in this embodiment, a gas purifier31is set onto the upstream side of the pressure regulator17in the gas lead-out passage16. A check valve32is set onto the upstream side of the gas purifier31. By assembling the gas purifier31into the container valve51, the impurities inside the gas such as oxygen, carbon monoxide, carbon dioxide and moisture etc. can be removed. This is also helpful to highly purify the gas in the semiconductor industry.

Furthermore, though the gas purifier31can be set at the downstream side of the pressure regulator17, the gas purifier is usually preferred to be set at the upstream side of the pressure regulator17because the pressure of the gas is high so that the purifying ability of the gas purifier31is therefore high. Additionally, the gas purifier31and the filter can be combined. Moreover, the check valve32, which prevents the impurity from returning by flowing with the gas from the gas purifier31, can be omitted.

FIG. 6is a system diagram showing a container valve with pressure reducing function according to the sixth embodiment of the present invention. In the container valve61with pressure reducing function as shown in this embodiment, a purge gas inlet41and a gas supplying outlet42communicate with the connection portion15aof the lead-out valve15through a valve seat portion. By setting the purge gas inlet41in this way, when the gas supplying line for the consumption equipment is connected to the gas lead-out outlet16b, the purge gas can be led in through the purge gas lead-in passage43and the purge gas feeds into the gas lead-out outlet16bthrough the purge gas inlet41and the connection portion15a. Therefore, the connection portion15aof the lead-out valve15or the gas lead-out outlet16bcan be effectively purged out.

In each container valve with pressure reducing function as shown in each embodiment, because the filling valve13, the lead-out valve15, the pressure regulator17, the safety relief valve22, the pressure sensor23, the filters24,25, the gas purifier31and the check valve32etc. can be optionally assembled into the valve block12according to demand, the whole body of the container valve can be miniaturized. Moreover, though it is preferred that these parts are integrated inside the valve block12, these parts can also be individually manufactured and then integrated by welding structures or connection structures in the case where connection structures are used, it is preferred to use metal surface seals applying leak-tight metal gaskets, such as VCR seal, W seal, C seal etc.

Additionally, in each valve block12in each embodiment, because the pressure regulator17and filters24,25etc. are structured in a shape for inserting into the gas container10, the container valve with pressure reducing function outside the container can be made greatly miniaturized. The filling valve13or the pressure sensor23also can be structured for inserting into the gas container. Only parts of the filling gas inlet14b, the gas lead-out outlet16band the purge gas lead-in passage43protrude out of the container to the lead-out valve15. Furthermore, the pressure regulator17is arranged protruding out of the container and the pressure of the pressure regulator17at its upstream side is adjustable.

The valve block12in the container valve with pressure reducing function can be manufactured by machining brass, stainless steel and nickel alloy etc. Generally, the stop valve (filling valve13, lead-out valve15) is the one of keyplate type or the one of diaphragm type. However, the one of diaphragm type is preferred because the dead space inside the valve can be effectively purged out. Moreover, it is preferred that the seat disk of each stop valve is made of polychlorotrifluorethylene (PCTFE), tetrafluoroethylene-perfluoro vinyl ether copolymer (PFA) and polyimide etc.

The driving for opening or closing each stop valve can be achieved by a manual valve or by an emergency stop valve operated by air pressure or electromagnetism. Especially, for reacting to emergency events during supplying gas, the lead-out valve15is preferred to be operated by air pressure or electromagnetism. The lead-out valve15is preferred to be operated by air pressure if the gas has inflammability or combustible-supportability.

Moreover, though a pressure regulator of spring type is generally used as the pressure regulator17, it is preferred to use a pressure regulator of diaphragm type whose dead space is small and generates few particles. The pressure at the downstream side of the pressure regulator17can be generally set at a range of 100 Torr˜1 MPa. If the pressure is set to be 0.1 MPa and below, it is preferred to arrange the pressure regulators in series with two sections to improve the precision of pressure control. One pressure regulator with a two-section pressure reducing function can also be used.

The safety relief valve22can be a rupture disc type, a spring type, a fusible-plug type or a type combined of these types. The pressure sensor23is chosen capable of matching the pressure of the filling gas. The pressure sensor23can be a Bourdon tube type, strain gauge type or semiconductor sensor type, wherein the semiconductor sensor type pressure sensor with diaphragm is preferred.

Filter media can be used to manufacture filters24,25, wherein the filter media is like polytetrafluoroethylene, ceramic, stainless steel, etc. When the gas is with high purity, the filter media made of stainless steel that releases little moisture is preferred. The filter capable of removing particles with diameters of 0.01˜20 μm and above can be used. For preventing the seat leakage due to the particles of the pressure regulator17, the filter24for 5 μm particles is used. On the other side, for supplying high purity gas with very few particles, the filter25for 0.01˜1 μm is set at the rear section of the pressure regulator17.

The purifier agent in the gas purifier31for removing the impurity within the gas can be suitably selected according to usage or the purity of the gas within the container, wherein the purifier agent is zeolite, active alumina, metal catalyst, metal oxide catalyst etc. Zeolite is preferred for removing moisture.

The whole surface of each constructing member contacting the gas is preferred to be mechanically polished, slurry polished, abrasive grains electrolytic polished, electro chemical-buffing, chemical polished, compound chemical polished etc. The surface also can be nickel-electro plating or nickel electroless plating. Moreover, nickel fluoride due to fluorination also can be formed onto the surface. If the valve block (body) is made of stainless steel, after the surface is polished and heat-treated, a passivation film also can be formed by oxide film of iron chromium or aluminum. The surface roughness i.e. Rmaxof these surfaces is preferred to be 1 μm and below and is more preferred to be 0.3 μm and below.

In the container valve with pressure reducing function, an example for gas filling operation of the gas container10is proposed to be explained as the container valve21with pressure reducing function as shown in the second embodiment. First, the gas container10is exhausted to vacuum as follows. The filling gas inlet14band gas lead-out outlet16bare respectively connected to the vacuum line. The gas container10is exhausted to vacuum under the condition of the filling valve13and lead-out valve15being opened. The gas and a part of the atmosphere inside the gas container10are exhausted till the pressure thereof is less than 1 Torr. If the gas is for semiconductor, the gas and a part of the atmosphere inside the gas container10are exhausted till the pressure thereof is less than 0.01 Torr. At this time, the gas container10can be placed at room temperature and it is preferred to heat the gas container10to a range of 250° C. and below. The term for exhausting the gas container to vacuum depends on its volume. After the gas container10is exhausted for 30 minutes˜20 hours, the lead-out valve15is closed and the gas is filled into the gas container10at a specific pressure through the filling gas inlet14b, the filling valve13, the gas filling passage and the gas filling outlet14a. Liquefied gas can be filled with the same filling operation. After the gas filling of the gas container10is finished, the gas container is checked to see whether a gas leakage exists. Then the gas lead-out outlet16bis moved to the place of gas consumption to connect the gas supplying line of gas consumption equipment.

When the gas inside the gas container10is supplied to the consumption equipment, after the gas lead-out outlet16bis connected to the gas supplying line, the purge gas with its pressure higher than the usage pressure is supplied to the gas supplying line to make sure whether a gas leakage exists. At this time, by repeat vacuuming the connection portion15a, or repeat vacuuming the connection portion15aand pressurizing to supply the purge gas into the connection portion15a, or repeat pressurizing to supply the purge gas into the connection portion15aand exhausting the connection portion15a, the atmospheric impurity mixed into the connection portion15awhen the line was connected is completely removed. If the gas required is of high purity for the semiconductor, with the example formed as the sixth embodiment, the purge gas is supplied to the gas lead-out outlet16bthrough the purge gas inlet41and the connection portion15a, and the atmospheric impurities remaining in the dead space of the lead-out valve15can be completely removed, wherein the purge gas is nitrogen, argon, helium or hydrogen etc.

Moreover, if the gas is for semiconductors, after the atmospheric impurities are removed from the connection portion, the gas supplying line is repeat vacuumed and pressurized to be filled with the semiconductor gas. Then the purge gas is exhausted and the gas inside the gas supplying line is replaced by the gas inside the connection portion. After that, by opening the lead-out valve15, the gas inside the gas container can be continuously supplied to the consumption equipment at a specific pressure.

If the indicator value of the pressure sensor23is low, after the lead-out valve15is closed, the gas-filling source is connected to the filling gas inlet14band the filling valve13is opened. In this way, the gas can be filled into the container on site. If the gas is not filled on site, the gas lead-out outlet16bis repeatedly vacuumed and pressurized to supply the purge gas, so as to fill the gas lead-out outlet16bwith the purge gas. After that, the gas supplying line is disconnected and the gas container is moved to a gas filling plant to fill new gas into the gas container.

FIGS. 7to9are substantial examples for the container valve with pressure reducing function as shown in the sixth embodiment, whereinFIG. 7is a vertical-sectional view,FIG. 8is a cross-sectional view andFIG. 9is a cross-sectional view of the main parts in the lead-out valve.

The container valve with pressure reducing function comprises a valve body51, a pressure regulator17and a filter25, wherein the pressure regulator17and the filter24are welded and integrated to the valve body51. The filling valve13, gas filling passage14, the lead-out valve15, the gas lead-out passage16, safety relief valve22, pressure sensor23, purge gas inlet41and the supplying gas outlet42are arranged in the valve body12. The surface thereof contacting gas is electro-polished or chemical polished to a degree with Rmaxequal to 1 μm for instance.

The gas container10is made of CrMo steel for example and the inner surface is chemical polished to a degree with Rmaxequal to 1 μm. The valve body51is made of SUS316L. A male thread (JIS-B8244 screw)52is set with a female thread in the container valve installation portion lob. The filling valve13is a manual valve of diaphragm type and is made of SUS316L. A handle13ais detachably formed and is disassembled when it is shipped from the gas filling plant. In the gas filling passage14, the filling gas inlet14bis located at the peripheral portion of the seat disk in the filling valve13and the gas filling outlet14ais located at the seat disk central portion.

The lead-out valve15is a valve of diaphragm type made of SUS316L and is operated by air pressure. The lead-out valve15also serves as an emergency valve. In the lead-out valve15, the purge inlet41connected to the purge gas lead-in passage and the supplying gas outlet42connected to the gas lead-out outlet16bare openings located at the peripheral portion of the seat disk53connected to the diaphragm so that the seat disk53is placed in between the purge inlet41and the supplying gas outlet42. At the central portion of the seat disk53, the gas lead-out passage16is penetrated at the gas lead-out inlet16aside. Additionally, the seat disk53is made of PCTFE.

The pressure regulator17is a valve of diaphragm type made of SUS316L. The pressure of the pressure regulator17at the downstream side thereof is set to be 0.15 MPa in advance for example. Moreover, the filter24is a metal filter made of SUS316L and is capable of removing particles whose diameter is 5 μm and above

A fusible-plug and a rupture disc are combined to be the safety relief valve22. The safety relief valve22is set to operate if the temperature is 155° C. and above or if the pressure is 25 MPa and above for example. The safety relief valve22is installed onto the valve body51so that the safety relief valve22is connected to the passage22abranching from the side of the gas filling passage14. The pressure sensor23is of the semiconductor sensor type with a diaphragm and is connected to the valve body51by the VCR connection. The pressure detecting range of the pressure sensor23is 0˜30 MPa. The pressure sensor23is installed onto the valve body51so that the pressure sensor23is connected to the passage23abranching from the side of the gas filling passage14.

Moreover, setting the status of the gas contacting surface, the pressure of the pressure regulator17at its downstream side, the specific temperature of the fusible-plug and the specific pressure of the rupture disc in the safety relief valve22, the pressure detecting range of the pressure sensor23, the particle removing ability of the filter24, the type of the gas filled into the gas container10or the usage of the gas are all dependant on the ambient during supplying gas. For example, if high purity gas is required for the semiconductor industry, the gas-contacting surface is polished till 0.1 μm in Rmaxand the filter24has relatively high ability to remove particles.

FIGS. 10 and 11are substantial examples showing that the pressure regulator17can be operated outside the container, whereinFIG. 10is a front-sectional view andFIG. 11is a cross-sectional view. Moreover, in these examples the structures, except for the installation position of the pressure regulator17, are systematically the same as the container valve with pressure reducing function as shown inFIGS. 7to9.

By welding only the filter24to be integrated onto the front end of the valve body51, the central portion of the gas lead-out passage16can be cut and can be bent outside the container of the valve body51. The upstream and downstream sides of the pressure regulator17are respectively connected to the bent passages17aand17b. In this way, by arranging the pressure regulator17outside the container, the pressure of the pressure regulator17at its downstream side can be adjusted according to demand while supplying gas.

With the structure of the container valve with pressure reducing function according the present invention, it is safe to supply various gases with inflammability, spontaneous flammability, toxicity, corrosiveness and combustion-supportability characteristics. Furthermore, the gas with high quality and high purity can be supplied by assembling the filter or the purifier. Additionally, the container valve can be made miniaturized by integrally assembling the pressure regulator etc. The portion outside the container can be made greatly miniaturized by inserting portions of parts into the gas container.

While the present invention has been described with a preferred embodiment, this description is not intended to limit our invention Various modifications of the embodiment will be apparent to those skilled in the art. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.