JP2008208877A - Method and device for detecting liquid leakage from double pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for detecting liquid leakage from a double pipe, capable of securely detecting liquid leakage from a liquid feeding pipe by an inexpensive configuration. <P>SOLUTION: To detect liquid leakage from the liquid feeding pipe 3 of the double pipe 7 comprising the liquid feeding pipe 3 and a protection pipe 5 covering the outer periphery of the liquid feeding pipe 3 leaving a space 6, one or a plurality of trap parts 13 for blocking the space 6 continued from one end to the other end of the protection pipe 5 by liquid leaked from the liquid feeding pipe 3 and trapped are formed. Gas is blown from one end of the protection pipe 5 to the space 6 by an air blowing means such as an exhaust blower 11, and in the other end part of the protection pipe 5, pressure change is detected by a pressure detecting means 12 to detect liquid leakage from the liquid feeding pipe 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a double pipe liquid leak detection method and apparatus for detecting a liquid leak in a double pipe comprising a liquid feed pipe and a protective pipe covering the outer periphery of the pipe with a space.

  2. Description of the Related Art Conventionally, for example, in a manufacturing factory for various semiconductor devices, various chemical solutions such as strong acidity and strong alkalinity and pure water required in the manufacturing process are disposed in a clean room 21 as shown in FIG. When supplying the machine (not shown) from the supply chamber 22 through the liquid supply pipe 23 with a supply pump (not shown), if the chemical liquid leaks from the liquid supply pipe 23, the surrounding environment may be hindered. Since it takes a lot of labor and time to recover, the outer periphery of the liquid feeding pipe 23 is covered with a protective pipe 25 by opening a space 24 to form a double pipe 26 so that the chemical liquid does not leak to the outside. Further, in order to detect that the liquid is leaking into the protective tube 25, a liquid reservoir 28 is provided on the protective tube so as to protrude downward at the lower end position of the U-shaped piping portion 27 in the piping path of the double piping 26. A liquid detection sensor 29 is provided in the liquid reservoir 28.

  In addition, in piping such as an oil supply pipe that connects between an oil tank and a measuring machine at a gas station, a protective pipe that covers the outer circumference of the pipe is provided to prevent the pipe from being damaged and causing oil leakage around it. A tube is provided with a liquid collecting part and a sensor for detecting the state thereof (for example, see Patent Document 1).

In addition, in pipes such as oil and gas, the peripheral surface of steel pipes is covered with a coating material made of FRP material, and a wire rod is arranged between the steel pipe and the coating material, and the leaked liquid in the event of a liquid leak is this wire rod. Is also known that is guided to the downstream part of the pipe and detected by a detection sensor (see, for example, Patent Document 2).
JP 7-267300 A JP 2001-108158 A

  However, in the configuration shown in FIG. 3, a U-shaped pipe portion 27 and a liquid reservoir portion 28 are provided at a branching portion of the liquid supply pipe 23, and a liquid detection sensor 29 needs to be provided for each liquid reservoir portion 28. Therefore, there are problems that a large number of liquid detection sensors 29 are required and the cost is increased, and that there is a possibility that moisture enters the liquid detection sensor 29 and malfunctions. In addition, when the protective tube 25 is broken, by detecting it and taking measures in advance, it is possible to prevent the liquid from leaking from the broken portion in the event of a liquid leak. There is also a problem that cannot be done.

  Also, the configuration described in Patent Document 1 has the same problem as the configuration of FIG. 3, and if it is attempted to reduce the number of locations where the liquid collection part is disposed, the pipe is inclined to collect the leaked liquid in the liquid collection part. If the pipe length is long, there is a problem that a large power is required for the supply pump. In addition, in the configuration described in Patent Document 2, the leaked liquid is guided to the detection sensor by the wire material, so that the location of the liquid leak cannot be specified. If it leaks out, there is a problem that the liquid leakage cannot be detected and the breakage of the covering material itself cannot be detected.

  In view of the above-described conventional problems, the present invention can reliably detect a liquid leak in a liquid feeding pipe with a low-cost configuration, and can easily identify a liquid leak location, or breakage of a protective pipe It is an object of the present invention to provide a method and an apparatus for detecting a liquid leak in a double pipe that can also detect the above.

  The liquid leakage detection method for a double pipe according to the present invention is a liquid leakage detection method for a liquid supply pipe in a double pipe comprising a liquid supply pipe and a protective pipe covering the outer periphery of the pipe with a space. One or a plurality of trap portions that are blocked by the liquid leaked from the liquid supply pipe and accumulated from the liquid supply pipe to the other end, and air is blown from one end of the protective pipe to the space, and the other end of the protective pipe The pressure change in the space is detected to detect liquid leakage from the liquid feeding pipe. The air blow to the space may be pumped from one end of the protective tube, but suctioning at the other end is preferable because breakage of the protective tube can be detected more easily and accurately as described later. It is.

  According to this configuration, the gas is blown from one end of the space between the liquid feeding pipe and the protective pipe, and the change in pressure at the other end of the space is detected. When the communication state of the space is interrupted by the leaked liquid, the pressure loss at that part increases and the detected pressure decreases greatly, so that the liquid leak can be detected reliably and even if there are many trap parts. Since it is only necessary to provide one air blowing means and pressure detection means, it can be configured at low cost, and the possibility of malfunction due to water intrusion into the detection means can be easily eliminated, resulting in high reliability and safety. Improves.

  Further, when air is blown into the space by suction at the other end of the protective tube and a change in the pressure of the space is detected at the other end of the protective tube, when the protective tube is broken, outside air flows from the damaged portion into the space. Since the pressure loss of the gas flow passing through the space is reduced and the detected pressure becomes higher than normal, the pressure change in the space at the other end of the protective tube is detected even when the pressure is higher than normal. By detecting it, breakage of the protective tube can be detected. In addition, when pressure is blown into the space from one end of the protective tube, airflow leaks from the damaged portion, and the detected pressure at the other end decreases as in the case where the trap portion is blocked by the leaked liquid. For this reason, the two cannot be distinguished and detected.

  Further, when the protective tube is made of a transparent member, the liquid leak location can be specified by visually detecting the trap portion where the liquid has accumulated.

  Further, instead of detecting the pressure change at the other end of the protective tube, the differential pressure on both sides of the trap portion may be detected. In this case, it is necessary to detect the differential pressure for each trap portion. Immediately identify the location of the liquid leak.

  Further, the double pipe liquid leakage detection device of the present invention is a liquid leakage detection apparatus for a liquid supply pipe in a double pipe comprising a liquid supply pipe and a protective pipe covering the outer periphery of the pipe with a space. One or a plurality of trap portions each including a liquid reservoir portion protruding downward and a partition plate that traverses the space and whose lower portion enters the upper portion of the liquid reservoir portion are provided from one end of the protective tube to the space. There are provided air blowing means for blowing gas and pressure detection means for detecting the pressure of the space at the other end of the protective tube.

  According to this configuration, if there is a liquid leak from the liquid supply pipe, the leaked liquid accumulates in the trap part, and the communication state of the space is interrupted. Even if there are many trap parts, it is possible to detect reliably, and it is only necessary to provide a single air blowing means and pressure detecting means, so that it can be configured at low cost and there is a risk of malfunction due to water intrusion into the detecting means. Can be easily eliminated, high reliability is obtained, and safety is improved.

  Further, when the protective tube is made of a transparent member, the liquid leak location can be specified by visually detecting the trap portion where the liquid is accumulated as described above.

  In addition, if a differential pressure detection means that detects the differential pressure on both sides of the trap part is provided in place of the pressure detection means, the location of liquid leakage can be immediately identified by detecting the differential pressure for each trap part as described above. can do.

  According to the double pipe liquid leakage detection method and apparatus of the present invention, a liquid supply pipe is obtained by blowing gas from one end of a space between the liquid supply pipe and the protective pipe and detecting a pressure change at the other end. If there is a liquid leak from the space, the leaked liquid accumulates in the trap portion provided in the middle of the space, and the communication state of the space is blocked by the leaked liquid. Therefore, liquid leakage can be reliably detected, and even if a large number of traps are provided, it is only necessary to provide a single air blowing means and pressure detection means. Can be detected.

  Hereinafter, an embodiment of a liquid leakage detection method and apparatus for a double pipe according to the present invention will be described with reference to FIGS. 1 and 2.

  In FIG. 1, 1 is a clean room in which various machines (not shown) used in the semiconductor device manufacturing process are arranged, and 2 is a storage tank (FIG. 1) that stores various chemicals and pure water used in the manufacturing process. (Not shown) is a supply chamber in which a supply pump (not shown) for supplying a chemical solution or the like toward the various machines is disposed, and the supply pump (not shown) and the machine (not shown) send the solution. Connected by a pipe 3. The chemicals and the like are fed in a temperature-controlled state so that proper characteristics can be stably obtained when used in each machine.

  The liquid feeding pipe 3 is composed of a chemical-resistant synthetic resin such as a fluororesin (for example, polytetrafluoroethylene) or a pipe material such as stainless steel. The liquid feeding pipe 3 is piped between the clean room 1 and the supply room 2 in the factory building or under the floor. In the middle of the pipe path, the liquid feeding pipe 3 rises downward and then rises up and bends in a U-shape. Alternatively, there are one or a plurality (usually a plurality) of U-shaped piping portions 4 that are curved in a U-shape.

  At least between the clean room 1 and the supply chamber 2, the outer periphery of the liquid feeding pipe 3 is covered with a protective pipe 5 with a space 6, and is configured as a double pipe 7. The protective tube 3 is made of a transparent synthetic resin such as transparent vinyl chloride. One end portion 5a of the protective tube 5 is inserted into the clean room 1, the end thereof is closed, and a suction port 8 having an opening / closing damper 9 having an adjustable opening degree is connected to the peripheral side thereof. The other end 5b of the protective tube 5 is inserted into the supply chamber 2 and the end thereof is closed, and an exhaust blower 11 is disposed at the tip of the suction duct 10 connected to the peripheral side thereof. Pressure detecting means 12 for detecting the internal pressure is provided. When the exhaust blower 11 is actuated, air is formed in the space 6 extending from the one end 5a to the other end 5b of the protective tube 5, so that the exhaust blower 11 constitutes a blowing means.

  At the lowest position of the U-shaped pipe section 4, a trap section that blocks the communication state of the space 6 communicating over the entire length of the double pipe 7 by collecting leaked liquid leaking from the liquid feeding pipe 3. 13 is provided. The trap portion 13 is cut off across the space 6 at a substantially central position in the tube axis direction of the liquid reservoir portion 14, and the lower portion is a liquid reservoir portion. It is comprised by the partition plate 15 which penetrate | invades into 14 upper part.

  In the above configuration, by operating a supply pump (not shown) in the supply chamber 2, a required chemical solution or the like is supplied to various machines (not shown) in the clean room 1 through the liquid supply pipe 3. Further, by operating the exhaust blower 11 in the supply chamber 2 at that time, the temperature-controlled air in the clean room 1 is sucked from the inlet 8 of the one end portion 5a of the protective tube 5 and the one end portion 5a of the protective tube 5 Then, the air is blown through the space 6 between the liquid feeding pipe 3 and the protective pipe 5 toward the other end portion 5 b arranged in the supply chamber 2. Since the temperature of the air flow flowing in the space 6 is controlled in this way, the chemical liquid supplied through the liquid feeding pipe 3 is not affected by the temperature change during the supply, and therefore the temperature of the chemical liquid etc. can be easily set. Proper management can be performed, and processing in various machines can be performed efficiently and accurately.

  Further, the air flow blown through the space 6 reaches the suction duct 10 at the other end 5b by receiving a predetermined pressure loss at the opening / closing damper 9 whose opening is adjusted by the suction port 8 and the trap part 13 in the middle. The pressure is detected by the pressure detection means 12. Here, when there is no liquid leakage from the liquid feeding pipe 3 and the air flow normally passes through the trap part 13 as shown in FIG. 2A, the pressure loss at the trap part 13 is relatively small. The pressure detected by the pressure detection means 12 is a value obtained by subtracting the pressure loss due to the opening / closing damper 9, the pressure loss due to passing through the space 6, and the pressure loss at the trap portion 13 from the pressure in the clean room 1. , It is detected as a normal value.

  On the other hand, the liquid leaks from any part of the liquid supply pipe 3, and as shown in FIG. 2B, the leaked liquid 16 is accumulated in the liquid reservoir 15 of the corresponding trap part 13, and the lower part of the partition plate 15 is When immersed in the leaked liquid 16, the communication state of the space 6 is blocked by the leaked liquid 16, and the pressure loss increases because the air flow passes through the leaked liquid 16. The detected pressure is greatly reduced from the normal value. Thus, if there is a liquid leak from the liquid feeding pipe 3, it can be reliably detected by pressure detection by the pressure detection means 12.

  In addition, even if there are a large number of trap portions 13, it is only necessary to provide a single exhaust blower 11 and pressure detection means 12. Further, since the pressure detection means 12 can be disposed in a place where there is no risk of water intrusion, there is no fear of malfunction due to ingress of water unlike the liquid detection sensor 29 of the conventional example, and high reliability is obtained and safety. Will improve. Further, since the protective tube 5 is made of a transparent synthetic resin, when a liquid leak is detected by the pressure detecting means 12 as described above, the trap portion in which the leaked liquid 16 has accumulated along the pipe path of the double pipe 7. By visually detecting 13, it is possible to identify the liquid leak location.

  In addition, as shown in FIG. 2C, when the protective tube 5 is damaged, the outside air flows into the space 6 from the damaged portion 17, so that the pressure loss of the gas flow passing through the space 6 is reduced. The pressure detected by the pressure detecting means 12 becomes higher than the normal value. Therefore, it is possible to detect the breakage of the protective tube 5 by configuring the pressure detection means 12 to detect a pressure change higher than the normal value. Therefore, when the protective tube 5 is broken, it is detected and measures are taken in advance, so that even if a liquid leaks, the liquid can be completely prevented from leaking from the broken portion 17 to the outside. be able to.

  In the above embodiment, the air is blown from the one end 5a of the protective tube 5 toward the other end 5b, but is sucked by the exhaust blower 11 at the other end 5b. A gas may be sent to the space 6 by pumping gas with a blower fan. However, in that case, the detected pressure of the pressure detecting means 12 decreases both in the shut-off state at the trap portion 13 in FIG. 2B and in the state in which airflow leaks from the damaged portion of the protective tube 5 in FIG. Therefore, it is difficult to distinguish and detect both.

  Moreover, in the said embodiment, although the pressure change was detected by the pressure detection means 12 in one place of the other end part 5b of the protective tube 5, the difference which detects the differential pressure | voltage of the both sides to each trap part 13 part. It can also be set as the structure which has arrange | positioned the pressure detection means (not shown). In that case, it is necessary to dispose a differential pressure detecting means (not shown) for each trap unit 13, which may increase the cost, but there is an advantage that it is possible to immediately identify the liquid leaking portion. In addition, in the case of a piping system having a small number of trap portions 13, it does not cause much cost increase.

  The liquid leakage detection method and apparatus for a double pipe according to the present invention is configured such that when there is a liquid leakage from a liquid feeding pipe, the leakage liquid is collected in a trap portion provided in the middle of the space between the liquid feeding pipe and the protective pipe. The liquid is blown from one end of the space and the pressure change at the other end is detected, so that liquid leakage in the liquid feeding pipe can be detected reliably, and various liquids that should not leak to the outside are sent. The present invention can be suitably applied to liquid leak detection in a double pipe that is fed.

The schematic block diagram of the liquid leak detection apparatus of the double piping in one Embodiment of this invention. (A)-(c) is an effect explanatory view in various states in the embodiment. The schematic block diagram of the liquid leak detection apparatus of the double piping of a prior art example.

Explanation of symbols

3 Liquid supply pipe 5 Protective pipe 6 Space 7 Double pipe 11 Exhaust blower (air blowing means)
12 Pressure detection means 13 Trap part 14 Liquid reservoir part 15 Partition plate

Claims (7)

  A liquid leakage detection method for a liquid supply pipe in a double pipe comprising a liquid supply pipe and a protective pipe covering the outer periphery of the liquid supply pipe, wherein the space continuous from one end to the other end of the protective pipe is from the liquid supply pipe One or a plurality of trap portions that are blocked by leaked and accumulated liquid are formed, gas is blown from one end of the protective tube to the space, and the pressure change in the space at the other end of the protective tube is detected to send liquid A method for detecting a liquid leak in a double pipe, characterized by detecting a liquid leak from the pipe.   2. The breakage of the protective tube according to claim 1, wherein the air is blown into the space by suction at the other end of the protective tube, and a change in the pressure of the space is detected at the other end of the protective tube to detect breakage of the protective tube. Liquid leak detection method for heavy piping.   2. The method of detecting a liquid leak in a double pipe according to claim 1, wherein the protective tube is made of a transparent member, and a liquid leak portion is specified by visually detecting a trap portion where the liquid is accumulated.   The method for detecting a liquid leak in a double pipe according to claim 1, wherein the pressure difference at both sides of the trap portion is detected instead of detecting the pressure change at the other end of the protective tube.   A liquid leakage detection device for a liquid supply pipe in a double pipe comprising a liquid supply pipe and a protective pipe covering the outer periphery of the liquid supply pipe, the liquid reservoir and the space provided by projecting downward from the protective pipe One or a plurality of trap portions each including a partition plate that traverses and whose lower portion enters the upper portion of the liquid reservoir portion are provided, and a blowing means for blowing gas from one end of the protective tube to the space, and the other end portion of the protective tube And a pressure detection means for detecting the pressure in the space.   The double pipe liquid leak detection device according to claim 5, wherein the protective tube is made of a transparent member.   The double pipe liquid leakage detection device according to claim 5 or 6, further comprising differential pressure detection means for detecting a differential pressure at both sides of the trap portion, instead of the pressure detection means.

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