JP2009133767A - Lining tank for supplying medical fluid and medical fluid leak diagnosing method in same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lining tank for supplying a medical fluid capable of getting the leak of a tank body or liquid surface measuring piping or the permeation advance degree of the medical fluid easily detected in the case where the lining tank for supplying the medical fluid is set to an unopened state (a state of keeping the medical fluid clean) and insulating resistance is measured in this state, and to provide a medical fluid leak diagnosing method in the lining tank for supplying the medical fluid. <P>SOLUTION: In a medical fluid lining tank 2 having a lining tank body 2a of which the inner surface is coated with a corrosion-resistant material, the liquid surface measuring piping 12 and a leak inspection device 36 for detecting the permeation of the medical fluid by measuring insulating resistance, the liquid surface measuring piping 12 and the lining tank body 2a are connected by an insulating bolt 40 and the presence of the leak caused by the permeation of the medical fluid in the lining tank body 2a or the liquid surface measuring piping 12 is detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chemical liquid supply lining tank used for semiconductor manufacturing and the like and a chemical liquid leakage diagnosis method in a chemical liquid supply lining tank.

  Conventionally, a chemical supply lining tank used in a chemical supply system for semiconductor manufacturing has a two-layer structure with a metal can body on the outer surface and a resin on the inner surface, and the inner lining layer made of the resin has chemical resistance. An insulating fluororesin excellent in purity is preferably used. Here, purity means that the lining layer on the inner surface of the tank contains substantially no impurities, coating-forming monomers, etc., and these components do not elute into the chemical solution in the tank, and are stored in the tank. It means not to contaminate the chemicals.

  Normally, when such a chemical solution supply lining tank is installed in a semiconductor factory, first, the lining tank and piping are cleaned for a certain period of time, and then the chemical solution used is put into the tank. Is done. And this chemical | medical solution continues being used in the state which does not open a tank for contamination prevention.

Further, the remaining amount of the chemical solution in the tank can be confirmed from the outside by measuring the remaining amount of the chemical solution introduced into the pipe for liquid level measurement without opening the tank.
Therefore, when the remaining amount of the chemical solution decreases, the chemical solution is introduced from the outside into the lining tank and can be continuously used without opening the tank.

  However, as described above, even if the tank is entirely lined with a corrosion-resistant material, the chemical solution permeates little by little over many years of use and permeates the lining layer, resulting in corrosion of the inner surface of the metal can body. There is. In this way, when permeation of the chemical solution to the lining layer occurs, the adhesive that causes the chemical solution to bond the metal can body and the lining layer deteriorates, and the lining layer is lifted from the surface of the can body, or the metal can near the boundary The gas generated here causes gas accumulation between the lining layer and the metal can body, resulting in swelling of the lining layer. In the worst case, the lining layer is destroyed and stored. It is expected that the chemical will be contaminated. In such a case, the semiconductor production line must be largely stopped and maintained. As a measure for avoiding such a situation, an inspection method (Patent Document 1) is known in which the degree of permeation of a chemical solution into a lining layer is confirmed by measuring an insulation resistance. However, the object of insulation resistance measurement in Patent Document 1 is limited to metallic equipment lined with a corrosion-resistant material.

  By the way, as described above, the lining tank for supplying a chemical solution is usually a double structure, the outer surface is a metal can body such as SUS, and the inner surface is a lining layer made of a fluororesin sheet integrated with a metal can body with an adhesive. It is configured. On the other hand, from the viewpoint of preventing corrosion, the liquid level measurement pipe also has a double structure, and the outer surface is made of a metal pipe and the inner surface is made of a lining layer coated with a corrosion-resistant material. And the joint part of this tank and the said piping is connected with the metal volt | bolt via the gasket.

In this state, that is, when the tank and the pipe for measuring the liquid level are connected with a metal bolt, even if the insulation resistance of the tank is measured for leak inspection, whether the tank is leaking or not. It was not possible to judge whether there was a leak in the piping for measurement.
Japanese Patent No. 2836097

  In the present invention, in view of such a conventional situation, in a state where the lining tank for supplying the chemical solution is not opened (a state in which the chemical solution is kept clean), the chemical solution permeation occurs in either the tank body or the pipe for measuring the liquid level. It is an object of the present invention to provide a chemical solution supply lining tank and a chemical solution leakage diagnosis method in the chemical solution supply lining tank that can easily detect whether or not the chemical solution permeation is advanced.

In order to achieve the above object, a chemical supply lining tank according to the present invention comprises:
A lining tank body with an inner surface coated with a corrosion-resistant material;
Piping for liquid level measurement;
A leakage inspection device that detects the permeation of chemicals by measuring insulation resistance,
The liquid level measurement pipe and the lining tank body are connected by an insulating bolt,
The presence or absence of leakage due to chemical permeation in the lining tank body or the liquid level measurement pipe is detected.

Further, the chemical leakage diagnosis method in the chemical supply pipe according to the present invention is as follows.
A leakage diagnosis method for detecting chemical permeation in the lining tank body or the pipe in a state where the lining tank body coated with the corrosion resistant material on the inner surface and a pipe coated with the corrosion resistant material on the inner surface are connected. There,
Connect the pipe and the lining tank body with an insulation bolt,
Insert one terminal of an insulation resistance meter into a part of the pipe,
Selectively connecting the other terminal of the insulation resistance meter to either the outer surface of the tank body or the outer surface of the pipe;
By measuring the insulation resistance, the presence or absence of leakage due to the permeation of chemical liquid in the lining tank body or the pipe is detected.

  According to the present invention as described above, by measuring the electrical resistance value, it is possible to easily determine whether there is leakage due to the permeation of the chemical liquid, and further whether the permeation occurs in the tank body or the piping. And the degree of progress can be checked.

  According to the chemical liquid supply lining tank and the chemical liquid leakage diagnosing method in the chemical liquid supply lining tank according to the present invention, the chemical liquid supply lining tank is not opened (the chemical liquid is kept clean) without the need to stop the production line. Thus, it is possible to specify whether the portion where the chemical solution permeates is the tank body or the pipe.

  Furthermore, the progress of transmission can be checked by continuously checking the insulation resistance value.

FIG. 1 shows a chemical supply lining tank 2 in which a leakage diagnosis method according to an embodiment of the present invention is implemented, and an attached piping system connected thereto.
The chemical liquid supply lining tank 2 is composed of a lining tank main body 2a formed with an upper opening and a lid 2b covering the opening.

  The lining tank main body 2a is provided with a short pipe 14 for introducing a chemical liquid and a long pipe 16 for taking out the chemical liquid stored in the lining tank main body 2a.

  The liquid supply pipe 14 has an opening above the liquid surface so as not to contact the liquid of the lining tank main body 2a, while the pipe 16 for taking out the chemical liquid is arranged so as to be immersed in the liquid. Further, the chemical solution supply pipe 14 and the chemical solution delivery pipe 16 are formed of a fluororesin tube having excellent corrosion resistance.

An opening 10 serving also as a drain is provided on the lower surface of the lining tank main body 2a, and a pipe 12 for liquid level measurement is connected.
Since the chemical solution supply lining tank 2 of this embodiment is always kept closed to prevent contamination of the stored chemical solution, the remaining amount of the chemical solution cannot be checked by looking through the tank. Therefore, in order to confirm the remaining amount from the outside, a liquid level measurement pipe 12 is provided separately.

  The liquid level measurement pipe 12 is arranged along the side surface of the lining tank main body 2a, and includes a fluororesin tube 17 and normal pipes 22 and 24 connected to the lining tank main body 2a. The pipes 22 and 24 are also lined with a corrosion resistant material such as a fluororesin.

  The fluororesin tube 17 arranged along the side surface of the lining tank main body 2a is supplied with the chemical solution in the lining tank main body 2a through the opening 10, and is displayed at the same level H as in the lining tank main body 2a. . By confirming this level H, the remaining amount of the chemical in the lining tank body 2a is confirmed.

  A joint 26, an opening / closing valve 20 and the like are installed in the middle of the pipe 22 from the lining tank body 2a to the fluororesin tube 17. An upper liquid return pipe 24 extending from the fluororesin tube 17 to the lining tank main body 2a communicates with the lining tank main body 2a.

  On the other hand, the joint 26 is connected to the opening 10 of the lining tank body 2a, the downstream side is divided into two branches, and the liquid discharge pipe 25 is connected to the opposite side of the pipe 12 for liquid level measurement. The liquid discharge pipe 25 is provided with opening / closing valves 28 and 30 and a container 32 for receiving the discharged chemical liquid. Further, a leakage inspection device 36 is provided between the opening / closing valve 28 and the opening / closing valve 30. The joint 26 and the inner peripheral surface of the leakage inspection device 36 are also lined with a corrosion resistant material. In addition, one end of the measurement electrode 34 is inserted into the leakage inspection device 36. The measurement electrode 34 is connected to an insulation resistance meter 52.

In the present invention, the insulating bolt 40 as shown in FIGS. 2 and 3 is used in the connecting portion 18 between the joint 26 and the opening 10 of the lining tank body 2a.
In this insulating bolt 40, the outer surface of the shaft portion 42 made of SUS304 or the like is covered with a fluororesin 43 excellent in insulation and corrosion resistance such as PVDF (polyvinylidene fluoride). The insulating bolt 40 is used as a connecting portion through washers 44 and 46 made of SUS304, insulating washers 50 and 51 made of FRP (Fiber Reinforced Plastics), and hexagon nuts 48 and 49 made of SUS304. .
As shown in the figure, in the connecting portion 18, an insulating bolt 40 is interposed, and an insulating gasket 53 is interposed between the pair of flanges 41 a and 41 b, so that the upstream side and the downstream side are interposed. Are electrically isolated.

The insulating bolt 40 formed in this way is used for the connecting portion 18 so that the downstream side of the connecting portion 18 is electrically insulated from the lining tank body 2a.
Now, the opening / closing valve 28 is closed and the opening / closing valve 20 is opened, and the chemical liquid L is filled in the lining tank body 2a. At this time, the level H of the chemical liquid L in the lining tank main body 2a is displayed in the pipe 12 for liquid level measurement and can be confirmed from here.

  When taking out the chemical solution from the tank 2, for example, if nitrogen gas is fed into the lining tank main body 2 a at a high pressure from another upper opening nozzle (not shown), the pressure presses the liquid surface, so that the liquid is sent out. The chemical solution rises from the lower end opening of the pipe 16 and is discharged outside the tank. Thereby, the required amount of the chemical solution is sent.

Hereinafter, a chemical leakage diagnosis method in such a chemical supply lining tank will be described.
First, the leakage diagnosis of the lining tank body 2a will be described.
Now, the inside of the lining tank main body 2a and the pipe 12 for liquid level measurement are filled with the chemical solution, and the opening / closing valve 20 and the opening / closing valve 28 are open.

  On the other hand, as described above, one terminal of the insulation resistance meter 52 is connected to the measurement electrode 34 in the flange leakage inspection device 36, but the other terminal 35 of the insulation resistance meter 52 is, for example, as shown in FIG. As shown, it is connected to the outer surface of the lining tank body 2a. Note that the opening / closing valve 28 and the opening / closing valve 30 are opened. Thereby, the chemical | medical solution L in the lining tank main body 2a is derived | led-out in the container 32 through the opening 10, the coupling 26, the on-off valve 28, and the valve 30. FIG. From this state, the insulation resistance is measured between the measurement electrode 34 connected in the leakage inspection device 36 and the measurement electrode 35 selectively connected to the outer surface of the lining tank body 2a. If this insulation resistance value is a normal state (resistance value of the lining material itself), it is considered that the chemical liquid does not permeate the lining layer in the lining tank body 2a.

Further, if the chemical liquid L in the lining tank main body 2a penetrates into the inner layer 4 of the lining tank main body 2a, the electrical resistance value between the terminal 34 connected to the chemical liquid L and the outer surface of the lining tank main body 2a is It is confirmed that it is lower than usual. Thereby, the permeation | transmission to the lining layer of the chemical | medical solution in the lining tank main body 2a is detected. The critical value of the electrical resistance value when permeation occurs in the lining tank body 2a is 1 × 10 ⁹ Ω. If it is less than this, it can be considered that the chemical | medical solution permeate | transmits a lining layer and the leak to the metal layer has arisen.

  On the other hand, if the other terminal 35 of the insulation resistance meter 52 is selectively connected to the outer surface of the liquid level measurement pipe 12 and the electrical resistance between the terminal 34 is measured while the chemical solution L is led out to the container 32, Leakage inspection can be performed on the liquid level measurement pipe 12. If this electrical resistance value is lower than usual, the chemical solution passes through the lining layer in the liquid level measurement pipe 12 and leakage to the metal layer is detected.

  In the present embodiment, the leakage inspection in the lining tank main body 2a and the leakage inspection in the liquid level measurement pipe 12 can be selectively performed in this way, so the lining tank main body 2a and the liquid level measurement Permeation with the pipe 12 can be diagnosed.

Note that a switch S may be provided on the other terminal 35 of the insulation resistor 52, and measurement may be performed by switching the switch S.
As described above, according to the present invention, it is possible to inspect the leakage of the lining tank main body 2a or the liquid level measurement pipe 12 without interrupting the use of the chemical solution in the lining tank main body 2a. Furthermore, it is possible to check the progress of leakage by continuously performing the inspection.

As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example at all.
For example, in the above embodiment, the insulating bolt 40 is used for the connecting portion 18, but if an insulating bolt is provided in addition to the connecting portion 18, leakage at a more detailed portion can be detected.

  Further, when the fluororesin tube 17 is constituted by a two-layer structure having a metal pipe on the outer surface and a lining layer coated with a corrosion-resistant material on the inner surface, an insulating bolt may be inserted into the connecting portion 55.

Furthermore, the piping path for installing the leakage inspection device 36 is not limited to the above embodiment.
For example, as shown in FIG. 4, a T-shaped connecting portion 38 that opens in three directions is provided in the opening 10 provided on the lower surface of the lining tank body 2a, and the straight portion of the three T-shaped paths is provided. It is also possible to connect the leakage inspection device 36 to a branched pipe that opens to the side, and to insert the measurement electrode 34 therein.

  Further, as shown in FIG. 5, a T-shaped connecting portion 54 opened in three directions is provided between the opening / closing valve 20 and the fluororesin tube 17 constituting a part of the liquid level measurement pipe 12. It is also possible to connect the leakage inspection device 36 to a pipe line that opens to the side among the three T-shaped paths, and to insert the measurement electrode 34 therein.

  Thus, the installation location of the leakage inspection apparatus 36 for installing the measurement electrode 34 is not limited to the example of FIG. When the leakage inspection device 36 is provided at the installation location shown in FIGS. 4 and 5, the inspection can be continuously performed.

  In the above embodiment, the chemical liquid supply lining tank to which the liquid level measurement pipe 12 is connected has been described. However, the present invention is also effective for a tank in which the liquid level measurement pipe 12 is not installed.

FIG. 1 is a sectional view showing a chemical solution supply lining tank and an attached piping system in which a chemical solution leakage diagnosis method according to an embodiment of the present invention is implemented. FIG. 2 is an explanatory diagram of an insulating bolt employed in a part of FIG. FIG. 3 is a cross-sectional view of a joint showing an example of use of the insulating bolt shown in FIG. FIG. 4 is a schematic view showing a part of a chemical supply lining tank according to another embodiment of the present invention. FIG. 5 is a schematic view showing a part of a chemical supply lining tank according to still another embodiment of the present invention.

Explanation of symbols

2 Chemical liquid supply lining tank 2a Tank body 2b Lid 4 Inner layer 12 Pipe for liquid level measurement 18 Connection 34 Measurement electrode 36 Leakage inspection device 40 Insulating bolt 52 Insulation resistor L Chemical liquid H Level

Claims (2)

A lining tank body with an inner surface coated with a corrosion-resistant material;
Piping for liquid level measurement;
A leak inspection device that detects chemical permeation by measuring insulation resistance;
The liquid level measurement pipe and the lining tank body are connected by an insulating bolt,
The lining tank for supplying a chemical solution, wherein the presence or absence of leakage due to the permeation of the chemical solution in the lining tank body or the liquid level measurement pipe is detected. A leakage diagnosis method for detecting chemical permeation in the lining tank body or the pipe in a state where the lining tank body coated with the corrosion resistant material on the inner surface and a pipe coated with the corrosion resistant material on the inner surface are connected. There,
Connect the pipe and the lining tank body with an insulation bolt,
Insert one terminal of an insulation resistance meter into a part of the pipe,
Selectively connecting the other terminal of the insulation resistance meter to either the outer surface of the tank body or the outer surface of the pipe;
A chemical leakage diagnosis method for a chemical supply lining tank, wherein the presence or absence of leakage due to chemical penetration in the lining tank body or the pipe is detected by measuring an insulation resistance.

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