JP4113546B2 - How to clean container valves - Google Patents

Description

The present invention relates to a method of cleaning a vessel fitted valve to the high pressure gas container.

  In a semiconductor manufacturing process or the like, anhydrous hydrogen chloride (HCl) is used, and this anhydrous hydrogen chloride is usually filled in a high-pressure gas container made of iron. As shown in FIG. 4, for example, a stainless steel container valve 10 is attached to the opening of a conventional high-pressure gas container. The container valve 10 has a container valve main body 11 and a plug 13 screwed into a cylinder portion 12 formed on the upper side of the container valve main body 11 and an upper end portion of the plug 13 via a spindle 19. And an attached handle 14. As shown in FIG. 5, a sheet disk 18 made of ethylene trifluoride chloride resin is provided at the lower end of the plug 13. A gas outlet 15 for taking out gas from the high-pressure gas container G is formed on the side surface of the container valve main body 11, and an outlet cap 16 is disposed in the gas outlet 15.

  Further, a gas flow path 17 whose one end side opens into the high-pressure gas container G is formed on the lower side of the container valve body 11, and the gas flow path 17 is moved up and down by moving the plug 13 through the handle 14. The opening on the other end side of 17 is opened and closed. That is, when using the gas in the high-pressure gas container G, the plug 13 is raised to open the opening on the other end side of the gas flow path 17, so that the gas passes through the gas flow path 17. It will be taken out from the outlet 15. When the use of the gas in the high-pressure gas container G is stopped, the plug 13 is lowered to close the opening on the other end side of the gas flow path 17. At this time, the opening of the gas flow path 17 is sealed by the sheet disk 18 formed at the lower end of the plug 13.

  After filling such high-pressure gas container G with liquefied hydrogen chloride, the gas outlet 15 is sufficiently warmed with a hot gun to improve gas escape, and then dry air is blown from the gas outlet 15 to perform air purge for several minutes, for example. The container valve 10 is cleaned for 10 to 15 minutes. After performing this air purge, the gas outlet 15 is warmed again with a hot gun to remove the moisture in the gas outlet 15 and the outlet cap 16 closes the gas outlet 15. In the case of a high-pressure gas container with a large amount of liquefied hydrogen chloride, air purge is performed for several hours, for example, 6 hours or more. In addition, a cycle purge in which vacuuming in the container valve 10 and pressurization in the container valve 10 are combined is also performed. The reason why such air purging, vacuuming, and pressurizing sequences are performed is that, conventionally, when liquefied hydrogen chloride is filled, liquefied hydrogen chloride enters along the inner wall of the cylinder portion 12 and the upper side of the plug 13 (sheet After entering the space existing on the opposite side of the surface and closing the container valve 10, the liquefied hydrogen chloride is gradually vaporized to fill the inner space of the outlet cap 16, and the outlet cap 16 is filled with the gas outlet 15. This is because it was considered that hydrogen chloride gas was released from the gas outlet 15 when it was removed. Thus, the high-pressure gas container G filled with liquefied hydrogen chloride is shipped to the user.

  However, if the outlet cap 16 is removed from the gas outlet 15 during use of the high-pressure gas container G after shipment, hydrogen chloride gas is slightly detected from the gas outlet 15 and the user leaks hydrogen chloride gas from the high-pressure gas container G. It was not possible to determine whether or not the high pressure gas container G was inspected again.

  From this, the present inventor supplied ammonia gas from the gas outlet 15 of the container valve 10 subjected to the air purge process or the cycle purge process, and investigated the contaminated portion in the container valve 10. I found out. That is, the attachment site of the liquefied hydrogen chloride F is not the upper part of the plug 13 or its side peripheral surface, but the plug 13 protruding from the threaded part of the cylinder part 12 when the container valve 10 is opened as shown in FIG. The lower peripheral surface and the bottom surface (the peripheral portion of the sheet disk 18) including the peripheral portion of the thread. The liquefied hydrogen chloride F is vaporized by a change in the temperature of the outside air, and it is considered that hydrogen chloride gas is released from the gas outlet 15 when the user removes the outlet cap 16 from the gas outlet 15. Considering these factors and the above-mentioned countermeasures, liquefied hydrogen chloride does not enter the upper portion of the plug 13, but the liquefied hydrogen chloride adhering to the aforementioned portion of the plug 13 is removed by air purge or It was found that even if vacuum evacuation and pressurized cycle purge were used, it could not be completely removed.

  Hydrogen chloride gas is highly hygroscopic and absorbs moisture to form hydrochloric acid, which is known to cause corrosion of stainless steel. For this reason, after the hydrogen chloride gas in the high pressure gas container G is consumed, when the outlet cap 16 is attached to the gas outlet 15, the container valve 10 is exposed to the atmosphere, so the hydrogen chloride adhering to the container valve 10 is attached. Absorbs moisture in the atmosphere and turns into hydrochloric acid. For this reason, after a long time has passed until the outlet cap 16 is closed and then collected by the manufacturer, the hydrochloric acid corrodes parts such as the plug 13 in the container valve 10, and the service life of the parts or the container valve 10 is increased. There is a problem that becomes shorter.

  In addition to hydrogen chloride gas as a halogen-based liquefied gas filled in the high-pressure gas container G, for example, chlorine (Cl2) gas, boron trichloride (BCl3), hydrogen bromide (HBr), bromine (Br2), dichlorosilane. As described above, the outlet cap is also filled with a halogen-based liquefied gas such as (SiH2Cl2), trichlorosilane (SiHCl3), silicon tetrachloride (SiCl4), fluorine (F2) gas, hydrogen fluoride (HF) gas. There is a problem that when the 16 is removed from the outlet 15, the gas leaks to the outside and the user cannot determine whether or not it is leaking. In addition, it is not preferable that these gases are released into the atmosphere even in a trace amount in view of safety to the human body.

Japanese Patent Laid-Open No. 7-260096 (paragraph 0014 FIGS. 1 and 2)

The present invention has been made in view of such circumstances, and an object of the present invention is to easily and reliably remove halogen-based liquefied gas adhering to the container valve in a container valve attached to a high-pressure gas container. An object of the present invention is to provide a container valve cleaning method that can be cleaned .

According to the present invention, a container valve that opens and closes a gas flow path by a seat disk provided at the bottom of the plug is attached to the high-pressure gas container by moving a plug in the cylinder part up and down with a handle on the upper side of the cylinder part. A method of cleaning the container valve after filling a high-pressure gas container with a halogen-based liquefied gas that is soluble in a solvent from a filling pipe through a gas outlet of the container valve,
Closing the container valve, a step of removing the pipe for the filling from the gas outlet,
Thereafter, with the gas outlet opening open to the atmosphere , the organic solvent is introduced into the container valve with the nozzle outlet of the cleaning tool directed to the lower or bottom area of the plug through the gas outlet from the outside. Supplying and cleaning the halogen-based liquefied gas adhering in the container valve;
Thereafter, a step of closing the gas outlet of the high-pressure gas container filled with the halogen-based liquefied gas with a cap is included. The organic solvent is supplied into the container valve by being injected with a propellant.

In another aspect of the invention, a container valve that opens and closes a gas flow path by a seat disk provided at the bottom of the plug is attached to the high-pressure gas container by raising and lowering the plug in the cylinder part with a handle on the upper side of the cylinder part. A method of cleaning the container valve after consuming a halogen-based liquefied gas that is filled in a high-pressure gas container and is soluble in an organic solvent ,
Closing the container valve and removing the pipe from the gas outlet of the container valve;
Thereafter, with the gas outlet opening open to the atmosphere , the organic solvent is introduced into the container valve with the nozzle outlet of the cleaning tool directed to the lower or bottom area of the plug through the gas outlet from the outside. Supplying and cleaning the halogen-based liquefied gas adhering in the container valve;
Thereafter, the step of closing the gas outlet of the high-pressure gas container in which the halogen-based liquefied gas has been consumed by a cap is included .

Furthermore, in the method of the present invention , a step of heating the gas flow path in the container valve may be performed before the step of cleaning the halogen-based liquefied gas.

The organic solvents include alcohols, ketones, esters, organic acids, for example ethanol, acetone, isopropyl alcohol (IPA), ethyl acetate, malic acid or mixtures thereof.

  According to the present invention, after filling the high-pressure gas container with the halogen-based liquefied gas or consuming the halogen-based liquefied gas in the high-pressure gas container, the propellant such as dimethyl ether (DME) is placed in the container valve while the container valve is closed. ) And an organic solvent such as ethanol are supplied, so that halogen-based liquefied gas such as liquefied hydrogen chloride adhering to the container valve can be easily and reliably washed off.

  Embodiments of the present invention will be described. The structure of the container valve attached to the high-pressure gas container G according to this embodiment is exactly the same as the container valve described with reference to FIG. The description of the container valve will be made using the container valve 10 shown in FIG.

  Next, a cleaning tool for cleaning the inside of the container valve 10 attached to the high-pressure gas container G will be described with reference to FIG. In FIG. 1, reference numeral 5 denotes a cleaning tool, and the cleaning tool 5 includes a can body portion 50 that is a sealed container and an opening / closing portion 51 provided on the top of the can body portion 50. The can body 50 contains a propellant 6 such as dimethyl ether (DME), which is a liquefied gas that generates pressurized gas, and an organic solvent 61 such as ethanol. The propellant 6 may be liquefied propane or a mixture thereof in addition to dimethyl ether, and may be a non-oxidizing compressed gas such as compressed nitrogen. In addition to ethanol, the organic solvent 61 may be acetone, isopropyl alcohol (IPA), or a mixture thereof. A nozzle 53 is attached to the opening / closing part 51. As shown in FIG. 2, an injection port 54 is formed on the tip side of the nozzle 53, and this injection port 54 is inserted into the gas extraction port 15 of the container valve 10. In this example, when the button 52 of the opening / closing part 51 is pressed, the cleaning agent composed of the propellant 6 and the organic solvent 61 is ejected from the ejection port 54.

  Next, a method for cleaning the inside of the container valve 10 will be described. First, a pipe for supplying liquefied hydrogen chloride (for filling) is connected to a gas outlet 15 of a container valve 10 attached to an empty high-pressure gas container G via a filling clamp, and the plug 13 is raised to raise a gas flow path 17. The liquid hydrogen chloride is supplied and filled into the high-pressure gas container G from the liquefied hydrogen chloride supply source through a pipe. Next, after the plug 13 is lowered and the opening of the gas flow path 17 is sealed with the seat disk 18, the pipe is removed. After that, the gas outlet 15 of the container valve 10 is heated with a hot gun for 1 minute, for example, and the moisture adhering to the filling clamp and the gas outlet 15 is dried. Then, the filling clamp is removed from the gas outlet 15, and the nozzle 53 of the cleaning tool 5 is inserted into the gas outlet 15.

  Then, by pressing the button 52 of the opening / closing part 51 with, for example, a finger, a cleaning agent composed of the propellant (pressurized gas) 6 and the organic solvent 61 is ejected from the ejection port 54 of the nozzle 53, and the inside of the container valve 10 is Washed.

  The state of this cleaning will be described in detail. The cleaning agent sprayed from the nozzle 54 at the tip of the nozzle is atomized, and the atomized cleaning agent (which is made into fine particles) collides with the plug 13, It collides with the part facing the gas outlet 15 on the side peripheral surface and the bottom surface, and wraps around the back surface side of the gas outlet 15 along the surface of the plug 13, whereby the gas outlet 15 and the space communicating with this in the plug 13. The cleaning agent will come into contact with the exposed parts. For this reason, when the container valve 10 is opened, it adheres to the lower side peripheral surface and the bottom surface (the peripheral portion of the seat disk 18) including the peripheral portion of the thread 13 of the plug 13 protruding from the threaded portion of the cylinder portion 12. The liquefied hydrogen chloride is dissolved by the organic solvent, washed away and discharged from the gas outlet 15 together with the organic solvent.

  After cleaning the inside of the container valve 10, the pH test paper is inserted from the gas outlet 15, and it is confirmed that the color of the pH test paper does not change. Dry with a hot gun. Before the outlet cap 16 is attached to the outlet 15, the outlet cap 16 is washed and dried with a hot gun, and then the outlet cap 16 is attached to the gas outlet 15. After the liquefied hydrogen chloride is filled in the high-pressure gas container G on the manufacturer side in this way, the high-pressure gas container G is transported under the user.

  According to the above-described embodiment, since the organic solvent is ejected from the nozzle 53 of the cleaning tool 6 into the gas outlet 15 in the container valve 10, it adheres to the plug 13 or the like that is the opening / closing means of the container valve 10. The liquefied hydrogen chloride can be easily and reliably removed. Since the long-time air purge that has been conventionally performed is not necessary, the working efficiency is good and the liquefied hydrogen chloride that has not been removed by the air purge can be removed. Therefore, when the user removes the outlet cap 16, the hydrogen chloride gas is removed. Does not leak, so the trouble of returning the high-pressure gas container G to the manufacturer and requesting re-inspection is also eliminated.

  In the cleaning method of the present invention, for example, after the user uses hydrogen chloride gas in the high pressure gas container G, the user cleans the container valve 10 attached to the high pressure gas container G on the user side in the same manner as described above. . In this case, when the gas flow path 17 is closed by the plug 13 of the container valve 10 and then the gas consumption pipe is removed from the container valve 10, the atmosphere enters the container valve 10 from the gas outlet 15, thereby Moisture in the atmosphere and hydrogen chloride react to form hydrochloric acid. However, as described above, liquefied hydrogen chloride or hydrochloric acid adhering to the container valve 10 is dissolved and washed away by washing with an organic solvent. Therefore, until the outlet cap 16 is subsequently closed and collected by the manufacturer, corrosion of parts such as the plug 13 is suppressed even after a long period of time, so that the service life of the parts or the container valve 10 can be extended. is there.

  In the above example, the high-pressure gas container G is filled with liquefied hydrogen chloride. However, as described above, the present invention is a halogen-based liquefied gas that dissolves in an organic solvent (highly soluble). Can be applied effectively. Examples of the halogen-based liquefied gas include HBr.

  Furthermore, although the pack type container valve 10 has been described in the above-described embodiment, the same effect can be obtained by washing the inside of the container valve in the same manner as described above in the case of the diaphragm type container valve.

Next, an experiment conducted for confirming the effect of the present invention will be described.
(Experimental example)
A. Example 1
In the cleaning tool 5 shown in FIG. 1, dimethyl ether (DME) is used as the propellant 6, ethanol is used as the organic solvent 61, and a mixed liquid of DME: ethanol = 4: 1 is used as the cleaning agent, As described above, the container valve 10 was cleaned after the liquefied hydrogen chloride was filled in the high-pressure gas container G. Then, after the cleaning of the container valve 10 was finished, the gas outlet 15 was dried with a hot gun. This is Example 1.

B. Example 2
The inside of the container valve 10 was washed and the gas outlet 15 was dried in the same manner as in Example 1 except that the organic solvent was acetone. This is Example 2.

C. Example 3
The inside of the container valve 10 was cleaned and the gas outlet 15 was dried in the same manner as in Example 1 except that the organic solvent was isopropyl alcohol (IPA). This is Example 3.

D. Example 4
For example, ethanol is supplied from the gas outlet 15 of the container valve 10 using a washing machine bottle in which an organic solvent is stored instead of the cleaning tool 5 shown in FIG. 1, so that the gas outlet 15 and a space communicating therewith are provided. Rinse with ethanol. After the inside of the container valve 10 was cleaned, the gas outlet 15 was removed of dirt and moisture with a waste cloth and dried with a hot gun. This is Example 4.

E. Comparative Example 1
The inside of the container valve 10 was washed and the gas outlet 15 was dried in the same manner as in Example 1 except that no organic solvent was used. This is referred to as Comparative Example 1.

F. Comparative Example 2
After filling the high-pressure gas container G with liquefied hydrogen chloride, the inside of the container valve 10 was not cleaned, the gas outlet 15 was dried with a hot gun, and air purge was performed for 15 minutes by blowing dry air from the gas outlet 15. . This is referred to as Comparative Example 2.
(Test method)
After cleaning the inside of the container valve 10 and drying the gas outlet 15, or after air purge and drying the gas outlet 15, an outlet cap 16 is attached to the gas outlet 15, and the high-pressure gas container G is installed all day and night. I left it alone. Next day, the outlet cap 16 was removed, a detector for detecting hydrogen chloride gas was attached to the gas outlet 15, and the concentration of hydrogen chloride released from the gas outlet 15 was measured.
(Results and discussion)
In FIG. 3, the result of the hydrogen chloride density | concentration of Examples 1-4 and Comparative Examples 1-2 is shown. As shown in FIG. 3, no hydrogen chloride gas was detected in Examples 1 to 3, but about 30 ppm of hydrogen chloride gas was detected in Comparative Example 1, and a large amount of hydrogen chloride gas exceeding 500 ppm was detected in Comparative Example 2. was detected. Therefore, by using a cleaning agent in which a propellant (DME) 6 and an organic solvent (ethanol, acetone, isopropyl alcohol) 61 are mixed, the liquefied hydrogen chloride adhering to the plug 13 can be surely washed off as described above. You can see that Also in Example 4, no hydrogen chloride gas was detected. From this, it is understood that the liquefied hydrogen chloride adhering in the container valve 10 can be removed also by supplying the organic solvent as it is without using the propellant. Although not experimented this time, in the background of the present invention, the detected concentration of hydrogen chloride gas when the outlet cap 16 was removed even after 6 hours of air purge was performed after the inside of the container valve 10 was dried with a hot gun. In light of the circumstances in which it frequently occurs that the content exceeds 30 ppm, it is understood that the method of the present invention is a simple and effective method.

It is sectional drawing which shows the cleaning tool connected to the said container valve. It is explanatory drawing which shows the connection state of the said container valve and a cleaning tool. It is explanatory drawing which shows the result of the experiment conducted in order to confirm the effect of this invention. It is sectional drawing which shows an example of the conventional container valve. It is a perspective view which shows a plug. It is an expanded sectional view showing a part of the container valve.

Explanation of symbols

G High-pressure gas container 10 Container valve 11 Container valve body 12 Cylinder part 13 Plug 15 Gas outlet 16 Outlet cap 17 Gas flow path 18 Sheet disk 5 Cleaning tool 50 Can body part 51 Opening / closing part 52 Button
53 nozzles

Claims (4)

A container valve that opens and closes the gas flow path by a seat disk provided at the bottom of the plug is attached to the high-pressure gas container by raising and lowering the plug in the cylinder part with the handle on the upper side of the cylinder part, and against the organic solvent A method of cleaning the container valve after filling a high-pressure gas container with a soluble halogen-based liquefied gas from a filling pipe through a gas outlet of the container valve,
Closing the container valve, a step of removing the pipe for the filling from the gas outlet,
Thereafter, with the gas outlet opening open to the atmosphere , the organic solvent is introduced into the container valve with the nozzle outlet of the cleaning tool directed to the lower or bottom area of the plug through the gas outlet from the outside. Supplying and cleaning the halogen-based liquefied gas adhering in the container valve;
Thereafter, the method of cleaning a container valve, characterized in that it and a step of closing the cap the gas outlet of the high pressure gas container halogenated liquefied gas is filled. A container valve that opens and closes the gas flow path by a seat disk provided at the bottom of the plug is attached to the high-pressure gas container by raising and lowering the plug in the cylinder part with the handle on the upper side of the cylinder part. A method for cleaning a container valve after consuming a halogenated liquefied gas that is soluble in an organic solvent ,
Closing the container valve and removing the pipe from the gas outlet of the container valve;
Thereafter, with the gas outlet opening open to the atmosphere , the organic solvent is introduced into the container valve with the nozzle outlet of the cleaning tool directed to the lower or bottom area of the plug through the gas outlet from the outside. Supplying and cleaning the halogen-based liquefied gas adhering in the container valve;
And a step of closing the gas outlet of the high-pressure gas container in which the halogen-based liquefied gas has been consumed with a cap , and a method for cleaning the container valve .   3. The container valve cleaning method according to claim 1, wherein the organic solvent is supplied into the container valve by being injected with a propellant. The method for cleaning a container valve according to any one of claims 1 to 3, wherein a step of heating the gas flow path in the container valve is performed before the step of cleaning the halogen-based liquefied gas.

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