JP2010082587A - Leakage detection method and leakage detector of hollow fiber membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leakage detection method and leakage detector of a hollow fiber membrane module allowing easy highly-accurate detection of leakage due to defect or damage of the hollow fiber membrane module without using liquid, dye or the like. <P>SOLUTION: Gas heated to 60°C or more or cooled 5°C or less is fed to a hollow fiber membrane front surface side from a gas feed port on the cylindrical module side face, in the hollow fiber membrane module with at least one ends of a hollow fiber membrane group comprising a plurality of hollow fiber membranes fixed in a respectively opened state. Temperature difference of gas passing through the hollow membranes and discharged from end openings thereof is detected by photographing using an infrared camera, preferably an infrared camera mounted with a microscope lens, to detect presence or absence of leakage of the hollow fiber membrane module. The infrared camera mounted with the microscope lens is used as a leakage detector of the hollow fiber membrane module. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a leak detection method and a leak detection apparatus for a hollow fiber membrane module. More specifically, the present invention relates to a leak detection method and a leak detection apparatus for a hollow fiber membrane module that can detect a leak of the hollow fiber membrane module with high accuracy and ease.

  Hollow fiber membrane modules are widely used for the separation of various gases, liquids, and solids such as pure water production, sterilization and turbidization of water, wastewater treatment, degassing, dehydration, and gas separation. For this reason, a leak due to a defect or damage of the hollow fiber membrane has a fatal effect on a system using the hollow fiber membrane module.

As a method for detecting defects (leakage) in the hollow fiber membrane, vacuum suction is performed from the opening on the end face of each hollow fiber membrane of the hollow fiber membrane module, air containing fine particles is introduced from the outer surface of the hollow fiber membrane, and the opening is opened. A method has been proposed in which air sucked from a part is transmitted through a particle counter and the number of fine particles in the sucked air is measured to detect the presence or absence of a defect. However, even though such a method can detect the presence or absence of leakage in the group of hollow fiber membranes, it is difficult to identify a defective hollow fiber membrane.
Japanese Examined Patent Publication No. 2-14084

  On the other hand, by scanning the laser beam in the surface direction of the opening, the scattered light generated when the laser beam hits the fine particles flowing out of the hollow fiber membrane where the defect exists is detected by a detector such as a CCD camera. Although there is a method for identifying a defective portion, it is not satisfactory in terms of detection accuracy, and there is a problem in its reliability.

In addition, with the opening surface of the hollow fiber membrane module wet with a liquid such as water or alcohol, air of a predetermined pressure is applied from the outside to the inside of the hollow fiber membrane, and the occurrence of bubbles on the opening surface at that time is determined. A method for detecting a leak location by specifying the number has also been proposed. However, in order to visually identify the location where bubbles are generated, the actual situation is often subject to the judgment of the operator. In particular, if the hollow fiber membrane diameter is very small, the bubbles become larger than the hollow fiber membrane diameter, so it is not easy to identify the leaking hollow fiber membrane and the adjacent hollow fiber membrane, and the leak location can be specified. It became even more difficult. Further, since it is necessary to dry the wet hollow fiber membrane module after the inspection, the number of processes is increased and the working time is also long.
JP-A-55-70258

Furthermore, there is a method in which the supply water with added dye is injected into the hollow fiber membrane module and the leaked dye is confirmed by this, but this has a problem that the dye remains in the hollow fiber membrane, and the outside of the hollow fiber membrane. A method is also proposed in which gas is leaked from the leaked portion of the bonded end of the hollow fiber membrane and the presence or absence of defects is detected using a refraction phenomenon according to the outflow status of the leaked gas using an optical system. However, since the refraction phenomenon extends to the periphery of the defective hollow fiber membrane, it is difficult to clearly identify only the defective hollow fiber membrane.
JP-A-53-13476

  An object of the present invention is to provide a leak detection method and leak detection for a hollow fiber membrane module that can easily detect a leak with high accuracy due to defects or damage of the hollow fiber membrane module without using a liquid or a dye. To provide an apparatus.

  An object of the present invention is to provide a hollow fiber membrane module in which at least one end face of a plurality of hollow fiber membrane groups is fixed in an open state, with a gas heated to 60 ° C. or higher or cooled to 5 ° C. or lower as a cylinder. The temperature difference between the gas supplied from the gas supply port on the side of the cylindrical module to the outer surface of the hollow fiber membrane and permeated through the hollow fiber membrane and released from the opening of the end surface is infrared camera, preferably an infrared camera equipped with a microscope lens This is achieved by detecting the presence or absence of leakage of the hollow fiber membrane module. An infrared camera equipped with a microscope lens is used as a leak detection device for a hollow fiber membrane module.

  With the leak detection method for a hollow fiber membrane module according to the present invention, there is an excellent effect that it is possible to easily detect a leak or a defect of the hollow fiber membrane module for each hollow fiber membrane. Such a detection method does not use a liquid or a dye, so that no foreign matter remains in the hollow fiber membrane and a step such as drying is not necessary. Moreover, since the detection accuracy is high, there is no fear of detection omission of the hollow fiber membrane module having a defective portion.

  As the hollow fiber membrane, any organic porous membrane or inorganic porous membrane can be detected as long as it is a porous membrane. Cellulose-based, PVA-based, EVA-based, Examples thereof include methylmethacrylic and polyacrylonitrile-based materials, and examples of the inorganic porous film include carbon-made and ceramic-made materials.

  The type of gas to be supplied is not particularly limited, but a gas having a large heat capacity, such as sulfur hexafluoride gas or carbon dioxide gas, is preferably used. When a gas having a large heat capacity is used, the temperature difference between the gas discharge location from the defective portion of the hollow fiber membrane and the peripheral portion thereof becomes large, so that the hollow fiber membrane having the defect is easily detected.

  In supplying the gas, a gas heated to 60 ° C. or higher, preferably 100 to 140 ° C. or cooled to 5 ° C. or lower, preferably -30 to 0 ° C. is used. In particular, in the case of a hollow fiber membrane module that is easily denatured by heat, the temperature difference is detected by cooling the supply gas. Here, when a gas other than the above temperature, particularly a gas of 15 to 35 ° C., is supplied, it is difficult to capture the difference in the amount of gas emission as a temperature difference image by an infrared camera.

  The gas is supplied to the hollow fiber membrane from the outer surface of the hollow fiber membrane on the side of the cylindrical module. The supplied gas permeates through the porous membrane on the surface of the hollow fiber membrane and flows in from there, and if there are defective parts such as poor potting or breakage of the hollow fiber membrane, the inside of the hollow fiber membrane is passed through them. It flows into the tube side and is discharged to the outside through the opening on the end surface of the hollow fiber membrane. At this time, since the gas inflow from the defective portion is overwhelmingly larger than the normal gas inflow from the porous membrane, and the gas is heated or cooled, the module opening is photographed with an infrared camera. The gas discharge location from the defective part is detected as a temperature difference image.

  When supplying the gas, the gas outlet side of the hollow fiber membrane module can be closed and the entire amount of gas can be supplied at the dead end, or the gas outlet side can be released and supplied so that the gas flows in the module. it can. In any case, the gas is preferably pressurized to, for example, about 0.05 to 0.3 MPa so that a differential pressure is generated between the outer surface of the hollow fiber membrane and the inner tube portion, so that the gas can easily flow from the defective portion. Therefore, detection becomes easy.

  The amount of gas released to the outside from the opening of the hollow fiber membrane end face correlates with the temperature difference, and is measured by photographing the temperature of the hollow fiber membrane end face with an infrared camera. That is, when shooting with heated gas supplied, the opening of the module terminal from which more gas is released exhibits higher temperature because more gas is released than other openings. It becomes like this. Here, if a microscope lens is attached to an infrared camera, it becomes possible to detect a temperature difference in a minute region, so that a defect can be easily detected even in a hollow fiber membrane having a small diameter or a portion where the hollow fiber membranes are densely packed. Become. A microscope lens having a spatial resolution of 10 to 63 μm is used.

  The hollow fiber membrane module that is the target of leak detection is used in a dry state.For example, in the case of a hollow fiber membrane module having a large pore size (100 nm or more) of the microfiltration class, the amount of gas inflow from the porous membrane is also large. In many cases, the temperature difference from the defect is difficult to occur, so the outer surface of the hollow fiber membrane is wetted with a liquid such as water in advance, so that the inside of the hollow fiber membrane hole is closed with a liquid to make it easy to cause a temperature difference. It is preferable to detect leaks.

  Next, the present invention will be described with reference to examples.

Example A cylindrical hollow fiber membrane module 1 (effective hollow fiber membrane length: 100 mm) shown in FIG. 1 comprising 500 carbon hollow fiber membranes having an outer diameter of 200 μm and an inner diameter of 150 μm was produced. In a dead end state in which the gas outlet 2 of the hollow fiber membrane module was closed, sulfur hexafluoride gas heated to 100 ° C. was supplied from the gas inlet 3 of the hollow fiber membrane module at a pressure of 0.1 MPa. In this state, the opening of the end surface of the hollow fiber membrane was photographed with an infrared camera 4 (Japan Avionics product TVS-500EX) equipped with a microscope lens with a spatial resolution of 18 μm. Observed as a clear red color. As a result, it was confirmed that these two hollow fiber membranes having a larger gas release amount than the other hollow fiber membranes had defects, and sulfur hexafluoride gas also flowed in from the defective portions.

It is a figure which shows the hollow fiber membrane module and infrared camera which were used in the Example.

Explanation of symbols

1 Hollow fiber membrane module 2 Infrared camera 3 Gas inlet 4 Gas outlet

Claims (3)

  A gas supply port on the side of the cylindrical module is supplied with a gas heated to 60 ° C. or higher or cooled to 5 ° C. or lower to a hollow fiber membrane module in which at least one end face of a plurality of hollow fiber membrane groups is fixed in an open state. The temperature difference of the gas supplied to the outer surface of the hollow fiber membrane and permeated through the hollow fiber membrane and released from the opening of the end face is measured by photographing with an infrared camera, and leakage of the hollow fiber membrane module is measured. A leak detection method for a hollow fiber membrane module, characterized by detecting presence or absence.   The leak detection method for a hollow fiber membrane module according to claim 1, wherein the gas is sulfur hexafluoride gas or carbon dioxide gas.   The leak detection apparatus of the hollow fiber membrane module used for the leak detection method of the hollow fiber membrane module of Claim 1 which attached the microscope lens to the infrared camera.

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