JP2007263942A - Method and apparatus for detecting membrane defect, and filtering device - Google Patents

Method and apparatus for detecting membrane defect, and filtering device Download PDF

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JP2007263942A
JP2007263942A JP2006304954A JP2006304954A JP2007263942A JP 2007263942 A JP2007263942 A JP 2007263942A JP 2006304954 A JP2006304954 A JP 2006304954A JP 2006304954 A JP2006304954 A JP 2006304954A JP 2007263942 A JP2007263942 A JP 2007263942A
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membrane
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potential difference
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Satoshi Shinohara
敏 篠原
Toru Yunoki
徹 柚木
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TORAITEKKU KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for detecting membrane defect, and a filtering device, capable of accurately and efficiently detecting a defect caused in a separation membrane. <P>SOLUTION: The method for detecting membrane defect comprises continuously measuring a potential difference between a reference electrode and a detecting electrode set on the permeating liquid side of the membrane, and detecting a defect of the membrane by fluctuation of the potential difference. The apparatus for detecting membrane defect comprises a reference electrode 16; detecting electrodes 17a, 17b, 17c and 17d set at least on the permeating liquid side of the membrane; and a measuring means 18 for continuously measuring a potential difference between the reference electrode and each detecting electrode. The filtering device comprises a membrane; a filtering means provided with the membrane; a reference electrode provided at a liquid supply port of the filtering means; a detecting electrode provided except the liquid supply port of the filtering means; and a measuring means for continuously measuring a potential difference between the reference electrode and each detecting electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、膜欠陥検出方法および膜欠陥検出装置、並びに、濾過装置に関する。   The present invention relates to a film defect detection method, a film defect detection apparatus, and a filtration apparatus.

浄水、超純水、パイロジェンフリー水などの製造において、最終の除粒子や除菌、除パイロジェンなどの目的で、限外濾過膜(UF膜)モジュールや精密濾過膜(MF膜)モジュールが使用されている。このようなモジュールでは、その使用中、膜に欠陥が生じた場合、製造された水の水質、例えば、微粒子数、濁度や菌数を測定することによって、当該欠陥の有無を検出している。   In the production of purified water, ultrapure water, pyrogen-free water, etc., ultrafiltration membrane (UF membrane) modules and microfiltration membrane (MF membrane) modules are used for the purpose of final particle removal, sterilization, and pyrogen removal. ing. In such a module, when a defect occurs in the membrane during use, the presence or absence of the defect is detected by measuring the quality of the produced water, for example, the number of fine particles, turbidity, and the number of bacteria. .

このような浄水装置には、複数の膜モジュールが使用されるが、微粒子や濁度を測定する機器は、モジュールごとにではなく、最終的に集合された水配管から採取して測定される。そのため、モジュール内の膜の欠陥がわずかな場合(例えば、多数の中空糸モジュールの中の1本の繊維が切断された場合)、その欠陥の検出は非常に困難であった。また、モジュールごとに検出装置を設置することも考えられるが、コストを考えるとあまり実用的ではない。   In such a water purifier, a plurality of membrane modules are used, but a device for measuring fine particles and turbidity is collected not from each module but from a finally assembled water pipe and measured. Therefore, when the defect of the film | membrane in a module is few (for example, when one fiber in many hollow fiber modules is cut | disconnected), the detection of the defect was very difficult. In addition, it is conceivable to install a detection device for each module, but this is not practical in view of cost.

中空糸膜モジュールのリークおよび欠陥の検出には、従来から種々の方法が提案されている。例えば、中空糸膜の内側に加圧空気を供給して中空糸膜の外側より圧力が高い状態を維持させ、このときの一定時間後の中空糸膜外側の液面の降下速度を測定することでリークを検出する方法(例えば、特許文献1参照)、中空糸膜モジュール内に所定の大きさの微粒子を一定濃度に分散させた気体を通し、中空糸膜モジュールを通過した不活性粒子を検出して欠陥を検出する方法(例えば、特許文献2参照)、中空糸膜外側から気体を圧入し、中空糸膜内側の中空糸膜端末へ出てくる気体によりリークを検出する方法(例えば、特許文献3参照)などである。   Various methods have been proposed for detecting leaks and defects in a hollow fiber membrane module. For example, supplying pressurized air to the inside of the hollow fiber membrane to maintain a higher pressure than the outside of the hollow fiber membrane, and measuring the descending speed of the liquid level outside the hollow fiber membrane after a certain time at this time (See, for example, Patent Document 1) for detecting leaks, passing a gas in which fine particles of a predetermined size are dispersed at a constant concentration through a hollow fiber membrane module, and detecting inert particles that have passed through the hollow fiber membrane module A method for detecting defects (for example, refer to Patent Document 2), a method for injecting gas from the outside of the hollow fiber membrane, and a method for detecting leakage by the gas coming out to the hollow fiber membrane terminal inside the hollow fiber membrane (for example, Patent Reference 3).

しかし、これらは未使用の中空糸膜の欠陥を検出する場合に適用したり、運転を一旦停止して調べるものであったりして検出精度が高くないという問題がある。また、運転中に透過水の濁度を測定しようとする場合には、中空糸膜のピンホールや切断糸の欠陥部分を被処理液中の懸濁物質等で塞いでしまうため欠陥を検出できないという欠点を有している。このように、従来技術では運転中に生じた中空糸膜の欠陥を運転中に検出することができなかったり、できたとしても装置が複雑になって測定が面倒であったりするものであった。しかしながら、中空糸膜の欠陥および切断の有無を、中空糸膜モジュールを運転中に検出することは透過液を安定供給する上で重要である。特に電子工業用の液体処理、飲料水用途に使用する場合には微粒子の混入や細菌等の漏出を素早く検出することが不可欠である。
特公平8ー2527462号公報 特開平7ー24273号公報 特開昭55ー70258号公報
However, these methods have a problem that the detection accuracy is not high because they are applied when detecting a defect of an unused hollow fiber membrane, or when the operation is temporarily stopped. In addition, when trying to measure the turbidity of permeated water during operation, the defect cannot be detected because the pinhole of the hollow fiber membrane or the defective part of the cutting thread is blocked with suspended substances in the liquid to be treated. Has the disadvantages. As described above, in the prior art, the defect of the hollow fiber membrane generated during the operation cannot be detected during the operation, or even if it is possible, the apparatus becomes complicated and the measurement is troublesome. . However, it is important for detecting the defect of the hollow fiber membrane and the presence or absence of cutting during the operation of the hollow fiber membrane module to stably supply the permeate. In particular, when used in liquid processing and drinking water applications for the electronics industry, it is indispensable to quickly detect contamination of fine particles and leakage of bacteria.
Japanese Patent Publication No. 8-2527462 JP-A-7-24273 JP-A-55-70258

本発明は、上記課題を解決することを目的とする。すなわち、本発明は、運転中でも、分離膜に生じた欠陥を迅速、かつ、高精度で効率よく検出できる膜欠陥検出方法および膜欠陥検出装置、並びに、濾過装置を提供することを目的とする。   The present invention aims to solve the above problems. That is, an object of the present invention is to provide a membrane defect detection method, a membrane defect detection device, and a filtration device that can quickly and efficiently detect defects generated in a separation membrane even during operation.

上記課題を解決すべく鋭意検討した結果、本発明者らは下記本発明に想到し、当該課題を解決できることを見出した。   As a result of intensive studies to solve the above problems, the present inventors have conceived the following present invention and found that the problems can be solved.

すなわち、本発明は、膜の欠陥を検出する膜欠陥検出方法であって、基準電極と、前記膜の透過液側に設置される検知電極との間の電位差を連続的に測定し、当該電位差の変動により前記膜の欠陥を検出することを特徴とする膜欠陥検出方法である。   That is, the present invention is a film defect detection method for detecting a film defect, and continuously measures a potential difference between a reference electrode and a detection electrode installed on the permeate side of the membrane, and the potential difference is detected. The film defect detection method is characterized in that the defect of the film is detected based on the fluctuation of the film.

本発明の膜欠陥検出方法は、液体が膜(分離膜)を透過する際に生ずる膜電位の電位差の変動から、膜の欠陥を検出する。膜電位は、水などの液体が膜の細孔を透過するときに、膜の表面の電気二重層との相互作用によって、膜の両側に電位として発生する。膜に欠陥(例えば、ピンホールや亀裂)が発生すれば、この電位が変動する。この変動を、上記基準電極と検知電極とで連続的に測定しながら検出すれば、運転中でも、欠陥が発生したときに瞬時に、かつ高精度で効率よくこれを検出することができる。   The membrane defect detection method of the present invention detects a membrane defect from the fluctuation of the potential difference of the membrane potential generated when the liquid permeates the membrane (separation membrane). The membrane potential is generated as a potential on both sides of the membrane due to the interaction with the electric double layer on the surface of the membrane when a liquid such as water passes through the pores of the membrane. If defects (for example, pinholes or cracks) occur in the film, this potential changes. If this variation is detected while continuously measured by the reference electrode and the detection electrode, it can be detected instantaneously, with high accuracy and efficiently when a defect occurs even during operation.

本発明の膜欠陥検出方法においては、前記電位差の変動値の絶対値が1mV以上となった場合に、前記膜の欠陥の存在を検出することが好ましい。また、前記膜としては、限外濾過膜および精密濾過膜のいずれかであることが好ましい。さらに、前記電位差の変動を測定する前に、圧力の変動を補正する補正処理を行うことが好ましい。かかる補正処理により、迅速に電位差を連続的測定し始めることができる。   In the film defect detection method of the present invention, it is preferable to detect the presence of the film defect when the absolute value of the variation value of the potential difference is 1 mV or more. The membrane is preferably either an ultrafiltration membrane or a microfiltration membrane. Further, it is preferable to perform a correction process for correcting the pressure variation before measuring the potential difference variation. By such correction processing, the potential difference can be quickly measured continuously.

また、本発明は、基準電極と、少なくとも膜の透過液側に設置される検知電極と、前記基準電極と前記検知電極との間の電位差を連続的に測定する測定手段と、を有することを特徴とする膜欠陥検出装置である。   Further, the present invention includes a reference electrode, a detection electrode installed at least on the permeate side of the membrane, and a measurement unit that continuously measures a potential difference between the reference electrode and the detection electrode. This is a characteristic film defect detection apparatus.

本発明の膜欠陥検出装置は、既述の本発明の膜欠陥検出方法を実施するのに最適であるため、運転中でも、分離膜に生じた欠陥を迅速、かつ、高精度で効率よく検出できる。また、微粒子カウンターを使用する従来の検出方法では、検出器が高価であるため、多数の検出器を一台の装置に設置することはコストの増大をもたらし実用的ではない。これに対し本発明の膜欠陥検出装置は、基本的に、電極および測定手段があればよく、低コストで実用的である。また、濾過手段が複数ある場合、それぞれに電極を設けるだけでよく、欠陥が検出された場合は、その濾過手段を交換すればよい。すなわち、欠陥が検出された場合に、すべての濾過手段による濾過を止めて、欠陥のある濾過手段を特定する必要が無いため、濾過処理の高効率化を図ることができる。   Since the membrane defect detection apparatus of the present invention is optimal for carrying out the above-described film defect detection method of the present invention, it is possible to quickly and efficiently detect defects generated in the separation membrane even during operation. . In addition, in the conventional detection method using the particle counter, the detector is expensive. Therefore, it is not practical to install a large number of detectors in one apparatus because the cost increases. On the other hand, the film defect detection device of the present invention basically requires electrodes and measurement means, and is practical at low cost. Further, when there are a plurality of filtering means, it is only necessary to provide an electrode for each, and when a defect is detected, the filtering means may be replaced. In other words, when a defect is detected, it is not necessary to stop filtering by all the filtering means and specify the defective filtering means, so that the efficiency of the filtering process can be improved.

本発明の膜欠陥検出装置においては、前記電位差の変動値の絶対値が1mV以上となった場合に、前記欠陥の存在を検出することが好ましい。膜に欠陥がない通常の状態では、電位差の変動というのはほとんど生じない。一方で、電位差の変動値の絶対値が1mV以上となると、欠陥の発生によるものと考えられる。そこで、変動値の絶対値が1mV以上の場合を欠陥の発生と判断することで、精度よく膜欠陥の検出を行うことができる。   In the film defect detection device of the present invention, it is preferable to detect the presence of the defect when the absolute value of the variation value of the potential difference is 1 mV or more. In a normal state in which there is no defect in the film, the potential difference hardly changes. On the other hand, when the absolute value of the fluctuation value of the potential difference is 1 mV or more, it is considered that a defect is generated. Therefore, it is possible to detect a film defect with high accuracy by determining that a defect is generated when the absolute value of the fluctuation value is 1 mV or more.

また、本発明の膜欠陥検出装置においては、前記膜が、限外濾過膜および精密濾過膜のいずれかであることが好ましい。これらの膜は、微粒子や微生物の除去に用いられ、基本的に連続使用可能であるため、本発明のような電位差の変動で欠陥の有無を判断することが好ましい。   In the membrane defect detection device of the present invention, the membrane is preferably either an ultrafiltration membrane or a microfiltration membrane. Since these films are used for removing fine particles and microorganisms and can basically be used continuously, it is preferable to determine the presence or absence of defects based on fluctuations in potential difference as in the present invention.

さらに、本発明は、膜と、前記膜を備えた濾過手段と、前記濾過手段の液供給口に設けられた基準電極と、前記濾過手段の前記液供給口以外に設けられた検知電極と、前記基準電極と検知電極との間の電位差を連続的に測定する測定手段と、を有することを特徴とする濾過装置である。   Furthermore, the present invention provides a membrane, a filtration means provided with the membrane, a reference electrode provided at a liquid supply port of the filtration means, a detection electrode provided at other than the liquid supply port of the filtration means, And a measuring unit that continuously measures a potential difference between the reference electrode and the detection electrode.

本発明の濾過装置は、既述の本発明の膜欠陥検出方法を実施しながら、濾過を行うことができる。そのため、運転中でも、分離膜に生じた欠陥を迅速、かつ、高精度で効率よく検出することが可能で、膜に欠陥が発生した場合には、迅速にその後の適切な処理を施すことができる。また、連続的に電位差を測定しながら欠陥を検出するので、サンプリングの必要が無く、検出のたびに装置を止める必要が無いため、膜処理の効率を高い状態に維持することができる。   The filtration device of the present invention can perform filtration while carrying out the above-described film defect detection method of the present invention. Therefore, it is possible to quickly and efficiently detect defects generated in the separation membrane even during operation, and if a defect occurs in the membrane, it can be promptly and appropriately processed. . In addition, since the defect is detected while continuously measuring the potential difference, there is no need for sampling, and there is no need to stop the apparatus for each detection, so that the efficiency of the film processing can be maintained at a high level.

本発明の濾過装置においては、上記本発明の膜欠陥検出装置の場合と同様に、前記膜が、限外濾過膜および精密濾過膜のいずれかであることが好ましい。   In the filtration device of the present invention, as in the case of the membrane defect detection device of the present invention, the membrane is preferably one of an ultrafiltration membrane and a microfiltration membrane.

本発明によれば、運転中でも、分離膜に生じた欠陥を迅速、かつ、高精度で効率よく検出できる膜欠陥検出方法および膜欠陥検出装置、並びに、濾過装置を提供することができる。   According to the present invention, it is possible to provide a membrane defect detection method, a membrane defect detection device, and a filtration device that can quickly and efficiently detect defects generated in the separation membrane even during operation.

〔膜欠陥検出方法〕
本発明の膜欠陥検出方法は、まず、膜へ液を供給する供給口に基準電極を設置し、膜の透過液側に検知電極を設置する。そして、これらの電極の間の電位差を連続的に測定する。膜に欠陥がない場合は、電位差に大きな変動が生じることがない。これに対し、膜に欠陥が発生した場合、瞬時に電位差が変動する。この変動を膜の欠陥として検出することで、運転中でも、欠陥(亀裂やピンホールなどの欠陥)を迅速、かつ、高精度で効率よく検出できる。
[Film defect detection method]
In the membrane defect detection method of the present invention, first, a reference electrode is installed at a supply port for supplying a liquid to the membrane, and a detection electrode is installed on the permeate side of the membrane. Then, the potential difference between these electrodes is continuously measured. When there is no defect in the film, the potential difference does not fluctuate greatly. On the other hand, when a defect occurs in the film, the potential difference changes instantaneously. By detecting this variation as a film defect, it is possible to detect defects (defects such as cracks and pinholes) quickly and efficiently with high accuracy even during operation.

欠陥が発生する前の検出電極の電位は、例えば、UF膜(限外濾過膜)の細孔内を水が透過したために生じる流動電位で、下記式(1)で表される。   The potential of the detection electrode before the defect is generated is, for example, a flow potential generated when water permeates through the pores of the UF membrane (ultrafiltration membrane), and is represented by the following formula (1).

V/P=(εεζ)/(ηκ)・・・式(1)
なお、上記式(1)中、Vは流動電位(中空糸膜内を透過する水によって生じた流動電位)、Pは膜間差圧、εおよびεは真空および水の誘電率、ζはゼータ電位、ηは水の粘度、κは水の電気伝導度を表す。
V / P = (ε 0 ε r ζ) / (ηκ) (1)
In the above formula (1), V is a flow potential (flow potential generated by water permeating through the hollow fiber membrane), P is a transmembrane pressure difference, ε 0 and ε r are vacuum and water permittivity, ζ Is the zeta potential, η is the viscosity of water, and κ is the electrical conductivity of water.

流動電位は、膜にかかる圧力や水温、電気伝導度によって変化するため、電位を計測するのと同時に、圧力、流量、温度、電気伝導度を測定しておき、その影響を補正する必要があるが、それらの影響を考慮し補正しても、電位の変化が認められる場合には、膜に欠陥が発生したと判断することができる。   Since the streaming potential changes depending on the pressure, water temperature, and electrical conductivity applied to the membrane, it is necessary to measure the pressure, flow rate, temperature, and electrical conductivity at the same time as measuring the potential, and correct the influence. However, even if corrections are made in consideration of these influences, if a change in potential is recognized, it can be determined that a defect has occurred in the film.

本発明の膜欠陥検出方法においては、電位差の変動値の絶対値が1mV以上となった場合に、膜の欠陥の存在を検出することが好ましい。通常の状態でも外部のなんらかの影響により、電位差が若干変動することがある。しかし、大きく変動したとしてもその変動値の絶対値が1mVを超えることはない。一方で、膜に欠陥が発生すると、供給液側と透過液側とが直接つながり、流速が大幅に変動するといったことから、その変動値の絶対値は1mV以上となる。従って、この値を基準に膜の欠陥を検出することが、実用的であり、非常に効率的であるといえる。   In the film defect detection method of the present invention, it is preferable to detect the presence of a film defect when the absolute value of the variation value of the potential difference is 1 mV or more. Even in a normal state, the potential difference may slightly fluctuate due to some external influence. However, even if it fluctuates greatly, the absolute value of the fluctuation value does not exceed 1 mV. On the other hand, when a defect occurs in the membrane, the supply liquid side and the permeate side are directly connected, and the flow velocity fluctuates greatly. Therefore, the absolute value of the fluctuation value is 1 mV or more. Therefore, it can be said that it is practical and very efficient to detect a film defect based on this value.

また、膜欠陥検出方法では、膜処理の運転の初期は、電位差が安定しないことがある。その場合は、電位差の変動値の絶対値が1mV未満となるまで待ってから、膜欠陥を検出するための電位差測定を連続的に行うことが好ましい。ここでいう「連続的」とは、膜処理運転中に電位差測定を行い続けることをいう。   In the film defect detection method, the potential difference may not be stable at the initial stage of the film processing operation. In that case, it is preferable to wait until the absolute value of the fluctuation value of the potential difference becomes less than 1 mV, and then continuously perform the potential difference measurement for detecting the film defect. The term “continuous” as used herein means that the potential difference measurement is continuously performed during the membrane processing operation.

本発明の膜欠陥検出方法では、膜へ液を供給する供給口に基準電極を設置し、膜の透過液側に検知電極を設置するが、濾過手段の大きさに応じて、検知電極をさらに増設してもよい。   In the membrane defect detection method of the present invention, the reference electrode is installed at the supply port for supplying the liquid to the membrane, and the detection electrode is installed on the permeate side of the membrane. It may be expanded.

なお、基準電極、検知電極、電位差を測定するための手段については、従来公知のものを使用することができる。基準電極の形態としては、ステンレスやチタンの棒や板が挙げられ、検知電極の形態としては、上記同様、ステンレスやチタンの棒や板が挙げられる。また、電位差を測定するための手段としては、基準電極および検知電極の電位を測定する電圧計が挙げられる。   As the reference electrode, the detection electrode, and the means for measuring the potential difference, conventionally known ones can be used. Examples of the reference electrode include stainless steel and titanium rods and plates, and examples of the detection electrode include stainless steel and titanium rods and plates. As a means for measuring the potential difference, a voltmeter that measures the potentials of the reference electrode and the detection electrode can be used.

〔膜欠陥検出装置〕
本発明の膜欠陥検出装置は、基準電極と、少なくとも膜の透過液側に設置される検知電極と、前記基準電極と前記検知電極との間の電位差を連続的に測定する測定手段と、を有する。本発明の膜欠陥検出装置は、既述の本発明の膜欠陥検出方法を実施するのに最適な装置である。本発明の膜欠陥検出装置は、種々の膜分離装置の膜欠陥検出に利用することができる。
[Film defect detector]
The membrane defect detection device of the present invention comprises a reference electrode, a detection electrode installed at least on the permeate side of the membrane, and a measurement means for continuously measuring a potential difference between the reference electrode and the detection electrode. Have. The film defect detection apparatus of the present invention is an optimal apparatus for carrying out the film defect detection method of the present invention described above. The membrane defect detection device of the present invention can be used for membrane defect detection of various membrane separation devices.

本発明の膜欠陥検出装置を、濾過手段としての中空糸膜モジュールの膜欠陥検出に適用した例として、図1を参照しながら説明する。   An example in which the membrane defect detection device of the present invention is applied to membrane defect detection of a hollow fiber membrane module as a filtering means will be described with reference to FIG.

中空糸膜モジュール10は、ハウジングケース11の内部に中空糸膜12を多数備えている。中空糸膜12の端末はハウジングケース11の両端部において、端末を開口した状態で封止部13a,13bにより封止されている。   The hollow fiber membrane module 10 includes a number of hollow fiber membranes 12 inside a housing case 11. The ends of the hollow fiber membrane 12 are sealed at both ends of the housing case 11 by sealing portions 13a and 13b with the ends opened.

この中空糸膜モジュール10は、中空糸膜12の内側から外側へろ過する内圧ろ過方式であり、一方の開口端14から矢印A方向へろ過対象流体を中空糸膜12の内径流路に流入させる。中空糸膜12を透過した透過流体はハウジングケース11の内部から流出口15a,15bを経て中空糸膜モジュール10から流出する。   This hollow fiber membrane module 10 is an internal pressure filtration system that filters from the inside to the outside of the hollow fiber membrane 12, and allows the fluid to be filtered to flow into the inner diameter flow path of the hollow fiber membrane 12 from one open end 14 in the direction of arrow A. . The permeated fluid that has passed through the hollow fiber membrane 12 flows out of the hollow fiber membrane module 10 from the inside of the housing case 11 through the outlets 15a and 15b.

ここで、本発明の膜欠陥検出装置のうち、基準電極16は、開口端14(液供給口)内に設ける。検出電極は、少なくとも、膜の透過液側である流出口の配管内に設ける(符号17a,17b)が、好ましくは、開口端14に最も近い流出口の配管内に設ける(符号17a)。そして、基準電極と検知電極との間の電位差を連続的に測定するための測定手段である電圧計18が、これらの電極と配線を通して繋がっている。なお、図1に示すように、検知電極は複数設けてもよい。すなわち、図1に示すように、中空糸膜モジュール10の中間部に検知電極17d、下流側に検知電極17cを設けてもよい。中空糸膜モジュール10に複数の検知電極を設ける場合は、液供給口とそれより下流側の端部との間に適当な間隔で設けることが好ましい。   Here, in the film defect detection device of the present invention, the reference electrode 16 is provided in the opening end 14 (liquid supply port). The detection electrode is provided at least in the outlet pipe on the permeate side of the membrane (reference numerals 17a and 17b), but is preferably provided in the outlet pipe closest to the open end 14 (reference numeral 17a). And the voltmeter 18 which is a measurement means for measuring the electric potential difference between a reference electrode and a detection electrode continuously is connected through these electrodes and wiring. As shown in FIG. 1, a plurality of detection electrodes may be provided. That is, as shown in FIG. 1, the detection electrode 17d may be provided in the middle part of the hollow fiber membrane module 10, and the detection electrode 17c may be provided on the downstream side. When a plurality of detection electrodes are provided in the hollow fiber membrane module 10, it is preferable to provide them at an appropriate interval between the liquid supply port and the downstream end.

電圧計により測定された電位は、コンピュータに取り込んでおき、電位差の変動値の絶対値が例えば、1mV以上となった場合には、警告が発せられるような機構を備えておくことが好ましい。当該警告により、欠陥が発生した中空糸膜モジュールの特定が可能となり、中空糸膜モジュールの交換を速やかに行うことが可能となる。   It is preferable that a potential measured by the voltmeter is taken into a computer, and a mechanism is provided so that a warning is issued when the absolute value of the fluctuation value of the potential difference becomes, for example, 1 mV or more. The warning makes it possible to identify the hollow fiber membrane module in which a defect has occurred, and to quickly replace the hollow fiber membrane module.

次に、本発明の膜欠陥検出装置を、濾過手段としての浄水器の膜欠陥検出に適用した例として、図2を参照しながら説明する。   Next, an example in which the membrane defect detection device of the present invention is applied to membrane defect detection of a water purifier as a filtering means will be described with reference to FIG.

浄水器20は、ハウジングケース21の内部に中空糸膜22を多数備えている。中空糸膜22の端末はハウジングケース21の上端部において、端末を開口した状態で封止部23により封止されている。そして、中空糸膜22は、通常は図2に示すように、U字型に束ねて接着されており、デッドエンド濾過(押し込み濾過)方式となっている。   The water purifier 20 includes a large number of hollow fiber membranes 22 inside the housing case 21. The end of the hollow fiber membrane 22 is sealed at the upper end of the housing case 21 by a sealing portion 23 with the end opened. The hollow fiber membrane 22 is usually bundled and bonded in a U shape, as shown in FIG. 2, and has a dead end filtration (indentation filtration) system.

この浄水器20も、原水の入り口24(液供給口)からろ過対象流体(例えば、水道水)を中空糸膜22の内径流路に流入させる。中空糸膜22を透過した透過流体(例えば、浄水)はハウジングケース21の内部から流出口25を経て浄水器20から流出する。   The water purifier 20 also allows a fluid to be filtered (for example, tap water) to flow into the inner diameter flow path of the hollow fiber membrane 22 from the raw water inlet 24 (liquid supply port). The permeated fluid (for example, purified water) that has passed through the hollow fiber membrane 22 flows out from the water purifier 20 from the inside of the housing case 21 through the outlet 25.

ここで、本発明の膜欠陥検出装置のうち、基準電極16および検知電極は、中空糸膜モジュールの場合と同様の配置とする。まず、原水の入り口24内に基準電極16を設ける。検出電極は、少なくとも、膜の透過液側である流出口25の配管内に設ける(符号17a)。そして、基準電極と検知電極との間の電位差を連続的に測定するための測定手段である電圧計18が、これらの電極と配線を通して繋がっている。なお、中空糸膜モジュールの場合と同様に、検知電極は複数設けてもよい。すなわち、図2に示すように、ハウジングケースの下端に検知電極17bを設けてもよい。また、浄水器の外側はプラスチック製であることが多いため、基準電極や検知電極をステンレス製とした場合は、これをプラスチック中に埋め込んで固定することが好ましい。   Here, in the membrane defect detection device of the present invention, the reference electrode 16 and the detection electrode are arranged in the same manner as in the case of the hollow fiber membrane module. First, the reference electrode 16 is provided in the raw water inlet 24. The detection electrode is provided at least in the piping of the outlet 25 on the permeate side of the membrane (reference numeral 17a). And the voltmeter 18 which is a measurement means for measuring the electric potential difference between a reference electrode and a detection electrode continuously is connected through these electrodes and wiring. As in the case of the hollow fiber membrane module, a plurality of detection electrodes may be provided. That is, as shown in FIG. 2, the detection electrode 17b may be provided at the lower end of the housing case. Moreover, since the outside of the water purifier is often made of plastic, when the reference electrode and the detection electrode are made of stainless steel, it is preferable to embed them in plastic and fix them.

電圧計により測定された電位は、コンピュータに取り込んでおき、電位差の変動値の絶対値が例えば、1mV以上となった場合には、警告が発せられるような機構を備えておくことが好ましい。当該警告により、欠陥の発生を認識することが可能となり、浄水器の交換時期が速やかにわかることになる。   It is preferable that a potential measured by the voltmeter is taken into a computer, and a mechanism is provided so that a warning is issued when the absolute value of the fluctuation value of the potential difference becomes, for example, 1 mV or more. The warning makes it possible to recognize the occurrence of a defect and quickly know when to replace the water purifier.

〔濾過装置〕
本発明の濾過装置は、膜と、この膜を備えた濾過手段と、濾過手段の液供給口に設けられた基準電極と、濾過手段の前記液供給口以外に設けられた検知電極と、基準電極と検知電極との間の電位差を連続的に測定する測定手段と、を有する。具体的には、公知の濾過手段に本発明の膜欠陥検出装置が組み合わされた構成となっている。従って、図1や図2に示すように、少なくとも、濾過手段である中空糸膜モジュール10や浄水器20に本発明の膜欠陥検出装置が装備された態様となる。
[Filtering equipment]
The filtration device of the present invention includes a membrane, a filtration means provided with the membrane, a reference electrode provided at a liquid supply port of the filtration means, a detection electrode provided other than the liquid supply port of the filtration means, and a reference Measuring means for continuously measuring a potential difference between the electrode and the detection electrode. Specifically, the film defect detecting device of the present invention is combined with a known filtering means. Therefore, as shown in FIG. 1 and FIG. 2, at least the hollow fiber membrane module 10 or the water purifier 20 as the filtering means is equipped with the membrane defect detection device of the present invention.

本発明の濾過装置は、複数の濾過手段を有していてもよい。この場合、それぞれの濾過手段に、膜欠陥検出装置を設ければよい。既述のように、本発明の膜欠陥検出装置は電極と測定手段とからなる簡易な構成であるため、装置の構成が複雑になることはなく、低コストなものとすることができる。   The filtration device of the present invention may have a plurality of filtration means. In this case, a film defect detection device may be provided for each filtering means. As described above, since the film defect detection apparatus of the present invention has a simple configuration including electrodes and measurement means, the configuration of the apparatus is not complicated, and the cost can be reduced.

本発明の膜欠陥検出方法においては、測定する電極間の電位は、装置の運転状況(例えば、濾過圧力、温度、モジュール入口の流量、水の電気伝導度等)により変化する場合がある。そうすると、測定の際に観察される電位の変動が、上記運転状況によるものであるのか、または、欠陥の発生によるものであるのか、その判別が困難となることがある。そこで、さらなる測定精度の向上を目的として、電位差の変動を測定する前に、圧力および流量など(特に、圧力)を補正する補正処理を行うことが好ましい。当該処理の概要としては、既述の式(1)に示したように、流動電位Vは膜間差圧Pに比例するが、測定される電位は中空糸内部の流れによって生じる電位が加算されているため、予め膜間差圧による電位の変化を測定しておき、圧力の変動を補正すればよい。同様に、他の変動要因についても補正を行うことが好ましい。   In the film defect detection method of the present invention, the potential between the electrodes to be measured may vary depending on the operation status of the apparatus (for example, filtration pressure, temperature, flow rate at the module inlet, electrical conductivity of water, etc.). In this case, it may be difficult to determine whether the potential fluctuation observed during the measurement is due to the above-described operating condition or due to the occurrence of a defect. Therefore, for the purpose of further improving the measurement accuracy, it is preferable to perform a correction process for correcting pressure, flow rate, etc. (especially pressure) before measuring the fluctuation of the potential difference. As an outline of the processing, as shown in the above-described equation (1), the flow potential V is proportional to the transmembrane pressure difference P, but the measured potential is added with the potential generated by the flow inside the hollow fiber. Therefore, the change in potential due to the transmembrane pressure difference is measured in advance, and the change in pressure may be corrected. Similarly, it is preferable to correct other fluctuation factors.

図1に記載のUFモジュール(但し、検出電極は17aおよび17bのみの構成)である中空糸膜モジュール(ダイセンメンブレンシステムズ社製FUS1582)に基準電極(ステンレス線:直径1mm,長さ1cm)と2つの検出電極(構成は基準電極と同様)とを設け、UFモジュールの入口圧力および出口圧力を下記表1に示すように変化させて純水の濾過を行い、既述のような補正処理を行った場合の補正処理前後の各電極の電位を連続的に測定した。結果を下記表1に示す。   A hollow fiber membrane module (FUS1582 manufactured by Daisen Membrane Systems Co., Ltd.), which is the UF module shown in FIG. Two detection electrodes (the configuration is the same as the reference electrode) are provided, and the inlet pressure and outlet pressure of the UF module are changed as shown in Table 1 below to filter pure water, and the correction process as described above is performed. In this case, the potential of each electrode before and after the correction process was continuously measured. The results are shown in Table 1 below.

Figure 2007263942
Figure 2007263942

上記表1より、平均膜間差圧の変動に伴い、検出電極17aおよび検出電極17bによって測定された電圧は1mV以上変動しているが、圧力の補正を行うことによって、補正後の電位の変動は、1mV以内になることがわかる。このように、装置の運転状況によって変動し得る電位を補正すれば、正常な運転状態での電位の変動はより迅速に1mV以内に収まり、膜の欠陥による電位変動のみが1mV以上の変動として検出される。   From Table 1 above, the voltage measured by the detection electrode 17a and the detection electrode 17b fluctuates by 1 mV or more due to the fluctuation of the average transmembrane pressure difference. However, the fluctuation of the corrected potential is obtained by correcting the pressure. Is found to be within 1 mV. In this way, by correcting the potential that can vary depending on the operating conditions of the device, the potential variation in the normal operating state is more quickly kept within 1 mV, and only the potential variation due to a film defect is detected as a variation of 1 mV or more. Is done.

膜欠陥検出装置および濾過装置も同様に、上記補正処理と行う補正手段を備えることが好ましい。かかる補正手段としては、濾過装置に通常設置される圧力発信機、流量発信機、電気伝導時計、温度計などの手段からの測定データを電位測定電極から測定値と共にコンピュータに取り込み、それらの数値を使用して補正式で電位を補正すればよい。   Similarly, it is preferable that the film defect detection device and the filtration device also include correction means for performing the correction processing. As such correction means, measurement data from means such as a pressure transmitter, a flow transmitter, an electric conduction clock, and a thermometer normally installed in the filtration device are taken into the computer together with the measurement value from the potential measurement electrode, and those numerical values are stored. What is necessary is just to correct | amend an electric potential by a correction type | formula.

(実施例)
図1に示すように、UFモジュールである中空糸膜モジュール(ダイセンメンブレンシステムズ社製FUS1582)に基準電極(ステンレス線:直径1mm,長さ1cm)と2つの検出電極(構成は基準電極と同様)とを設けた。純水の濾過を行って、基準電極の電位を基準として各電極の電位との差を連続的に測定した。
(Example)
As shown in FIG. 1, a hollow fiber membrane module (FUS1582 manufactured by Daisen Membrane Systems Co., Ltd.), which is a UF module, has a reference electrode (stainless steel wire: diameter 1 mm, length 1 cm) and two detection electrodes (the configuration is the same as the reference electrode). And provided. Pure water was filtered, and the difference from the potential of each electrode was continuously measured based on the potential of the reference electrode.

各電極の電位の変動の絶対値が1mV未満となってから、中空糸膜モジュールの長手方向中間部に位置する中空繊維1本に、直径0.5mm程度のピンホールを設けた。この際も各電極の電位の測定は続行した。濾過条件を下記表2に示し、測定結果を下記表3に示す。なお、検出電極(1)とは、図1の符号17aに相当し、検出電極(2)とは、図1の符号17dに相当する。   After the absolute value of the fluctuation of the potential of each electrode was less than 1 mV, a pinhole having a diameter of about 0.5 mm was provided in one hollow fiber located at the middle portion in the longitudinal direction of the hollow fiber membrane module. At this time, the measurement of the potential of each electrode was continued. The filtration conditions are shown in Table 2 below, and the measurement results are shown in Table 3 below. The detection electrode (1) corresponds to the reference numeral 17a in FIG. 1, and the detection electrode (2) corresponds to the reference numeral 17d in FIG.

Figure 2007263942
Figure 2007263942

Figure 2007263942
Figure 2007263942

上記表3より明らかなように、ピンホールを設けると、直ちに各電極で電位の大きな変動が確認された。すなわち、検出電極(1)では、欠陥発生前における基準電極と検知電極と電位差が22mVであったのに対し、欠陥発生後では当該電位差が19mVと変動し、欠陥発生前後の電位差の変動値の絶対値が3mVとなった。同様に、検出電極でも、当該変動値の絶対値が3mVとなった。
このように濾過手段に基準電極と検出電極とを設け、その電位を連続的に測定し、変動を観察することで、欠陥を迅速、かつ、高精度で効率よく検出できることがわかる。
As is clear from Table 3 above, when a pinhole was provided, a large fluctuation in potential was immediately observed at each electrode. That is, in the detection electrode (1), the potential difference between the reference electrode and the detection electrode before the occurrence of the defect was 22 mV, but after the defect occurred, the potential difference fluctuated to 19 mV. The absolute value was 3 mV. Similarly, also in the detection electrode, the absolute value of the fluctuation value was 3 mV.
In this way, it is understood that the defect can be detected quickly, efficiently and efficiently by providing the reference electrode and the detection electrode in the filtering means, continuously measuring the potential, and observing the fluctuation.

本発明の膜欠陥検出装置を濾過手段に適用した態様を説明する一部断面切断説明図である。It is a partial cross section cutting explanatory drawing explaining the aspect which applied the film | membrane defect detection apparatus of this invention to the filtration means. 本発明の膜欠陥検出装置を他の濾過手段に適用した態様を説明する一部断面切断説明図である。It is a partial cross section explanatory drawing explaining the aspect which applied the film | membrane defect detection apparatus of this invention to the other filtration means.

符号の説明Explanation of symbols

10・・・中空糸膜モジュール
11,21・・・ハウジングケース
12,22・・・中空糸膜
13a,13b,23・・・封止部
14・・・開口端
15a,15b,25・・・流出口
16・・・基準電極
17a,17b,17c,17d・・・検知電極
18・・・電圧計
20・・・浄水器
24・・・原水の入り口
DESCRIPTION OF SYMBOLS 10 ... Hollow fiber membrane module 11, 21 ... Housing case 12, 22 ... Hollow fiber membrane 13a, 13b, 23 ... Sealing part 14 ... Open end 15a, 15b, 25 ... Outlet 16: reference electrodes 17a, 17b, 17c, 17d ... detection electrode 18 ... voltmeter 20 ... water purifier 24 ... inlet of raw water

Claims (9)

膜の欠陥を検出する膜欠陥検出方法であって、
基準電極と、前記膜の透過液側に設置される検知電極との間の電位差を連続的に測定し、当該電位差の変動により前記膜の欠陥を検出することを特徴とする膜欠陥検出方法。
A film defect detection method for detecting a film defect,
A membrane defect detection method comprising: continuously measuring a potential difference between a reference electrode and a detection electrode installed on the permeate side of the membrane, and detecting a defect in the membrane by a change in the potential difference.
前記電位差の変動値の絶対値が1mV以上となった場合に、前記膜の欠陥の存在を検出することを特徴とする請求項1に記載の膜欠陥検出方法。   2. The film defect detection method according to claim 1, wherein the presence of a defect in the film is detected when an absolute value of a fluctuation value of the potential difference becomes 1 mV or more. 前記膜が、限外濾過膜および精密濾過膜のいずれかであることを特徴とする請求項1または2に記載の膜欠陥検出方法。   The membrane defect detection method according to claim 1 or 2, wherein the membrane is one of an ultrafiltration membrane and a microfiltration membrane. 前記電位差の変動を測定する前に、圧力の変動を補正する補正処理を行うことを特徴とする請求項1〜3のいずれか1項に記載の膜欠陥検出方法。   The film defect detection method according to claim 1, wherein a correction process for correcting a pressure fluctuation is performed before the fluctuation of the potential difference is measured. 基準電極と、
少なくとも膜の透過液側に設置される検知電極と、
前記基準電極と前記検知電極との間の電位差を連続的に測定する測定手段と、を有することを特徴とする膜欠陥検出装置。
A reference electrode;
A sensing electrode installed at least on the permeate side of the membrane;
A film defect detection apparatus comprising: a measurement unit that continuously measures a potential difference between the reference electrode and the detection electrode.
前記電位差の変動値の絶対値が1mV以上となった場合に、前記欠陥の存在を検出することを特徴とする請求項5に記載の膜欠陥検出装置。   The film defect detection device according to claim 5, wherein the presence of the defect is detected when an absolute value of a fluctuation value of the potential difference becomes 1 mV or more. 前記膜が、限外濾過膜および精密濾過膜のいずれかであることを特徴とする請求項5または6に記載の膜欠陥検出装置。   The membrane defect detection device according to claim 5 or 6, wherein the membrane is one of an ultrafiltration membrane and a microfiltration membrane. 膜と、
前記膜を備えた濾過手段と、
前記濾過手段の液供給口に設けられた基準電極と、
前記濾過手段の前記液供給口以外に設けられた検知電極と、
前記基準電極と検知電極との間の電位差を連続的に測定する測定手段と、を有することを特徴とする濾過装置。
A membrane,
Filtration means comprising the membrane;
A reference electrode provided at a liquid supply port of the filtering means;
A detection electrode provided in addition to the liquid supply port of the filtering means;
And a measuring means for continuously measuring a potential difference between the reference electrode and the detection electrode.
前記膜が、限外濾過膜および精密濾過膜のいずれかであることを特徴とする請求項7に記載の濾過装置。   The filtration device according to claim 7, wherein the membrane is one of an ultrafiltration membrane and a microfiltration membrane.
JP2006304954A 2006-05-23 2006-11-10 Method and apparatus for detecting membrane defect, and filtering device Pending JP2007263942A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101023792B1 (en) * 2010-04-22 2011-03-21 주식회사 파라 Apparatus for detecting damage of filtration membrane using piezoelectric effect
KR101753453B1 (en) 2014-05-30 2017-07-04 롯데케미칼 주식회사 Hollow fiber membrane and method of detecting damage of membrane thereof
CN112546870A (en) * 2020-11-25 2021-03-26 南京工业大学 In-situ repair technology

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101023792B1 (en) * 2010-04-22 2011-03-21 주식회사 파라 Apparatus for detecting damage of filtration membrane using piezoelectric effect
KR101753453B1 (en) 2014-05-30 2017-07-04 롯데케미칼 주식회사 Hollow fiber membrane and method of detecting damage of membrane thereof
CN112546870A (en) * 2020-11-25 2021-03-26 南京工业大学 In-situ repair technology

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