EP1494788A1 - Cross flow filtration system and method for locating defects - Google Patents

Cross flow filtration system and method for locating defects

Info

Publication number
EP1494788A1
EP1494788A1 EP03746211A EP03746211A EP1494788A1 EP 1494788 A1 EP1494788 A1 EP 1494788A1 EP 03746211 A EP03746211 A EP 03746211A EP 03746211 A EP03746211 A EP 03746211A EP 1494788 A1 EP1494788 A1 EP 1494788A1
Authority
EP
European Patent Office
Prior art keywords
filter element
valve
line
compressed air
shut
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03746211A
Other languages
German (de)
French (fr)
Inventor
Eduard Hartmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bucher Guyer AG
Original Assignee
Bucher Guyer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bucher Guyer AG filed Critical Bucher Guyer AG
Publication of EP1494788A1 publication Critical patent/EP1494788A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/10—Testing of membranes or membrane apparatus; Detecting or repairing leaks
    • B01D65/102—Detection of leaks in membranes
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L2/00—Non-alcoholic beverages; Dry compositions or concentrates therefor; Their preparation
    • A23L2/02—Non-alcoholic beverages; Dry compositions or concentrates therefor; Their preparation containing fruit or vegetable juices
    • A23L2/08—Concentrating or drying of juices
    • A23L2/082—Concentrating or drying of juices by membrane processes
    • A23L2/087—Concentrating or drying of juices by membrane processes by ultrafiltration, microfiltration
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L2/00—Non-alcoholic beverages; Dry compositions or concentrates therefor; Their preparation
    • A23L2/70—Clarifying or fining of non-alcoholic beverages; Removing unwanted matter
    • A23L2/72—Clarifying or fining of non-alcoholic beverages; Removing unwanted matter by filtration
    • A23L2/74—Clarifying or fining of non-alcoholic beverages; Removing unwanted matter by filtration using membranes, e.g. osmosis, ultrafiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/18—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/20—Accessories; Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/22—Controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/02—Forward flushing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/18—Use of gases
    • B01D2321/185—Aeration

Definitions

  • the invention relates to a cross-flow filtration system of the type mentioned in the preamble of claim 1 and to a method for fault location in such a system according to the preamble of claim 7.
  • Such cross-flow filtration systems are used advantageously when it comes to molecularly disperse or colloidally disperse substance mixtures, at most with proportions of solid or To filter suspended solids.
  • mixtures of substances are mixtures of substances which initially arise in the production of fruit and fruit juices. These mixtures of substances are then separated by filtration into clear fruit or fruit juice on the one hand and the essentially remaining turbid substances on the other.
  • activated carbon can also be added to the mixture of substances before the filtration in order to achieve certain effects. This activated carbon must then also be separated from the liquid with the cloudy substances.
  • a cross-flow filtration system of the type mentioned in the preamble of claim 1 is known from WO-Al-01/51186.
  • a solution is shown here how blockages of the filtration module can be removed by fixed retentate portions.
  • the problem with systems of this type is that the filter elements can become blocked, so that production has to be interrupted in order to first remove the blockages. Production interruptions are undesirable.
  • a waste water treatment device is known from JP-A-07 112 185, and a cleaning method using compressed gas is also disclosed.
  • a method for cleaning membrane filters is known from JP-A-06226 065.
  • the cleaning is done by backwashing with the use of air.
  • a filtration system is known in which, after the completion of a filtration cycle, rinse water can be fed in via a valve, which serves to displace highly viscous retentate residues from the filter unit. Such a flush can clogging can be prevented if initiated in good time.
  • the initiation of the rinsing is not without problems because the viscosity changes quickly.
  • the retentate can become blocked in the membrane tubes of the filtration module.
  • membrane modules for such cross-flow filtration systems are known. They contain tubular membranes, which are arranged in the membrane module in a wound, curved form. A large number of such membrane modules can be arranged parallel to one another in the crossflow filtration system. For example, systems are known from WO-Al-01/51186 which have 800 membrane tubes connected in parallel.
  • a defect in a single membrane tube due to a leak then leads to the filtration no longer being successful because the permeate obtained is no longer clear.
  • a turbidity sensor it can be recognized if this is the case, but there is then the problem of locating the defective membrane tube.
  • a visual inspection in such a way that the place with the greatest cloudiness is searched for is usually not useful.
  • the invention has for its object to provide a cross-flow filtration system which is designed so that it can be used to carry out a method for fault location.
  • Fig. 1 is a schematic of a cross-flow filtration system
  • Fig. 2 details of a filter element.
  • 1 means a filter element in which the desired liquid phase is separated from the mixture of substances.
  • the design of the filter element 1 is not important. The invention is primarily used when the filter element 1 contains, for example, straight or wound tubular membranes or capillary tubes, since such filter elements 1 mostly process substance mixtures with high turbidities. If parts of the filter element 1 become blocked, this regularly leads to an interruption in operation with all its disadvantageous consequences.
  • the mixture of substances to be filtered is located in a product tank 2. From there it passes through a feed line 3 to the filter element 1.
  • a feed pump 4 and a flow meter 5 are inserted into the feed line 3, the speed of the feed pump 4 through the flow meter 5 in the manner It can be controlled or regulated that either the delivery rate through the supply line 3 or the pressure in the supply line 3 at the input of the filter element 1 remains constant. This enables economical production in a known manner.
  • a tank shut-off valve 6 which can be actuated by a motor or pneumatically.
  • a permeate line 7 is connected to it, through which the permeate separated off in the filter element 1, for example the clear fruit juice, can be removed.
  • a return line 8 leads from the filter element 1 to the product tank 2, in which the retentate is returned from the filter element 1 to the product tank 2.
  • a throttle valve 9 is inserted, which can also be actuated by a motor or pneumatically.
  • This throttle valve 9 is from a retentate line Pressure sensor 10 controllable from, which detects the pressure at the retentate input of the filter element 1.
  • a further retentate line pressure sensor 10 ′ can be arranged on the return line 8 directly behind the filter element 1.
  • the pressure in the supply line 3 which can be detected by the retentate line pressure sensor 10 directly in front of the filter element 1 is related to the delivery capacity of the feed pump 4 and the state of the filter element 1.
  • the throttle valve 9 can now be opened or closed more or less by motor or pneumatically.
  • a return line shut-off valve 11 which is always open when the retentate leaving the filter element 1 is to be returned to the product tank 2.
  • the mixture of substances in the product tank 2 is conveyed to the filter element 1 with the aid of the feed pump 4 when the tank shut-off valve 6 is open.
  • Filter element 1 is separated from the permeate mixture.
  • the retentate is returned to the product tank 2 through the return line 8 with the return line shut-off valve 11 open.
  • the viscosity of the circulating mixture of substances increases in the course of the filtration process, because the proportion of solid or suspended substances in the mixture of substances increases the more permeate has been separated in filter element 1.
  • the filtration performance drops.
  • the viscosity of the mixture of substances has reached a certain level, the filtration must be stopped, and in good time so that the filter element 1 cannot become blocked.
  • the circulating mixture of substances can therefore be removed from the circuit by opening an outlet valve 12 which is arranged behind the filter element 1.
  • the mixture of substances to be filtered is first fed to the product tank 2 via a product line 13.
  • the feed pump 4 then goes into operation. Initially, the mixture of substances contained in the product tank 2 is relatively low-viscosity.
  • the feed pump 4 is controlled so that the delivery rate through the supply line 3 remains constant.
  • Permeate is separated off in the filter element 1, so that the retentate leaving the filter element 1 has a higher viscosity. This retentate is returned to the product tank 2. Its amount is due to the deposition of Permeate in filter element 1 smaller.
  • 13 additional substance mixture is fed through the product line. As the process progresses, the viscosity of the mixture of substances in the product tank 2 increases further and further.
  • Filter element 1 located product, the permeate, is not diluted by rinsing water, it is drained before the start of the rinsing process.
  • a rinse water tank 14 is provided, from which rinse water can be fed into the feed line 3 through a rinse line 15.
  • a flush line shut-off valve 16 is used. Between the rinse water tank 14 and the rinse line shut-off valve 16 there is another element, the task of which is to prevent significant amounts of the substance mixture from flowing back from the feed line 3 to the rinse water tank 14 when the rinse line shut-off valve 16 is opened.
  • the tank shut-off valve 6 is closed more or less simultaneously and that
  • Flush line shut-off valve 16 opened.
  • the tank shut-off valve 6 and the flushing line shut-off valve 16 are actuated by a control unit 20, with which the filtration process can be controlled.
  • a control unit 20 with which the filtration process can be controlled.
  • the flushing line shut-off valve 16 is opened more or less simultaneously and the tank shut-off valve 6 is closed, a difference in level H between the content in the product tank 2 and the content in
  • Rinse water tank 14 then flow mixture of substances from product tank 2 to rinse water tank 14 if the difference in level H has a certain size, also increasing take into account that the density in the product tank 2 is greater than that of the rinse water in the rinse water tank 14. This penetration of significant amounts of the mixture of substances in the direction of the rinse water tank 14 is prevented by the element mentioned. Since the rinsing line 15 is usually several meters long in known filtration systems, the rinsing water tank 14 is spared from the ingress of substance mixture. The water contained in the rinse water tank 14 is therefore not contaminated.
  • This element preventing the mixture reflux is either a check valve 17 or a reflux throttle 17 ', as is known from the Swiss patent application 0204/02.
  • a compressed air line 25 opens into the supply line 3 to the filter element 1 and can be shut off by a compressed air shut-off valve 26.
  • a compressed air shut-off valve 26 By opening the compressed air shut-off valve 26, the flushing water located in the filter element 1 is displaced from the filter element 1 by means of compressed air. So that the compressed air does not penetrate into the feed line 3 and the feed pump 4 and the flow meter 5 arranged therein, it is also necessary to arrange a feed line shut-off valve 28 in the vicinity of the filter element 1 in the feed line 3.
  • the outlet valve 12 known from the Swiss patent application 0204/02 is advantageously arranged directly behind the filter element 1, as shown in FIG. 1. If the retentate or the rinsing water is displaced from the filter element 1, the primary circuit of the filter element 1 is filled with air. If one of the individual parts of the filter element 1 has a leak, air will pass through this leak into the secondary circuit of the filter element 1. Visually, the exact location of the leak can now be recognized very easily. In order to be able to recognize a leak in the filter element 1, it is advantageous if the pressure of the air in the filter element 1 is slowly increased.
  • an adjustable throttle 27 is advantageously arranged between the compressed air shut-off valve 26 and the confluence of the compressed air line 25 into the supply line 3. It is thus possible to slowly increase the air pressure acting on the filter element 1. Then it is very easy to observe at which point of the filter element 1 air emerges. The location of the defect is thus localized. The system can now be shut down and the defect can be remedied by replacing the defective part.
  • Filter element 1 are displaced. However, this is not possible with a slowly increasing pressure of the air, especially if the filter element 1 contains a plurality of membrane modules connected in parallel, as will be shown.
  • a switchable OPEN-CLOSE valve 29 can advantageously be arranged parallel to the adjustable throttle 27, as is shown in FIG. 1 by dashed lines.
  • the procedure is advantageously as follows.
  • the OPEN-CLOSE valve 29 After opening the compressed air shut-off valve 26, the OPEN-CLOSE valve 29 is opened and thereby the rinsing water from the filter element 1 is quickly and completely displaced using an air pressure of about 3 to 6 bar. Then the OPEN-CLOSE valve 29 is closed again. Then, with the help of the adjustable throttle 27, the air pressure can be slowly increased until the bubble point is reached.
  • This variant is advantageous because it is not possible to increase the pressure very quickly by means of an adjustable throttle 27, as is necessary to almost completely displace the rinsing water from the filter element 1.
  • the compressed air line 25 advantageously has a memory 32. This means that a sufficient amount of compressed air is available in the immediate vicinity of the cross-flow filtration system. In fact, there is often the problem that compressed air lines which are in operation do not have a large cross section and are relatively long.
  • This memory 32 is advantageous in order to guarantee that the filter element 1 is blown out completely and quickly.
  • the size of the store 32 depends on the conditions of the cross-flow filtration system, namely in particular on the dimensions of the filter element 1.
  • control lines leading from the control unit 20 to the compressed air shutoff valve 26 and to the supply line shutoff valve 28 are not shown in FIG. 1.
  • the compressed air in the accumulator 32 advantageously has a pressure of at least 3 bar.
  • the upper limit for the pressure is given by the load limit for the filter element 1, which can be approximately 6 bar, for example.
  • FIG. 2 shows a filter element 1, as is known in principle from WO-Al-01/51186.
  • the same reference numerals mean the same elements as in FIG. 1.
  • the filter element 1 contains a large number of membrane modules 40 which are arranged parallel to one another between the feed line 3 and the return line 8.
  • the filter element 1 is pressurized with compressed air from the compressed air line 25
  • a leak in one of the membrane modules 40 can be recognized very easily by the fact that bubbles 41 rise from the location of the leak due to the liquid in the filter element 1. This makes it easy to determine the location of the defect. The defective membrane module 40 can thus be found easily and then exchanged.
  • Production cycle occurs, that is, when the viscosity of the retentate is still low, so that it is possible to directly displace the retentate from the filter element 1 by means of compressed air. Flushing with compressed air before the start of the leak search is then not necessary.

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  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Nutrition Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Filtration Of Liquid (AREA)

Abstract

The invention relates to a cross flow filtration system comprising at least one filtering element (1) to which a substance mixture from a product tank (2) is supplied via a supply line (3). Rinsing water from a rinsing water tank (14) can also be supplied to the filtering element (1). According to the invention, a supply line check valve (28) is mounted before the entry of the supply line (3) into the filtering element (1), and a compressed-air line (25) leads into the filtering element (1) on the entry side while being able to be blocked by a compressed-air check valve (26). The retentate or rinsing water can be forced out of the filtering element (1) by compressed air by closing the supply line check valve (28) and opening the compressed-air check valve (26). Air enters the secondary circuit of the filtering element (1) when the filtering element (1) has a leak. It is then easy to notice the location on the filtering element (1) air from which air exits whereby enabling the defect to be localized. The invention renders the maintenance and repair of a defective filtering element (1) very simple.

Description

Querstrom-Filtrationsanlage und Verfahren zur FehlerortungCross-flow filtration system and method for fault location
Die Erfindung bezieht sich auf eine Querstrom-Filtrationsanlage der im Oberbegriff des Anspruchs 1 genannten Art sowie auf ein Verfahren zur Fehlerortung bei einer solchen Anlage gemäß dem Oberbegriff des Anspruch 7.The invention relates to a cross-flow filtration system of the type mentioned in the preamble of claim 1 and to a method for fault location in such a system according to the preamble of claim 7.
Solche Querstrom-Filtrationsanlagen werden vorteilhaft angewendet, wenn es darum geht, molekulardisperse oder kolloiddisperse Stoffgemische, allenfalls mit Anteilen von Festbzw. Schwebstoffen, zu filtrieren. Beispiele für solche Stoffgemische sind Stoffgemische, wie sie bei der Produktion von Frucht- und Obstsäften zunächst anfallen. Diese Stoffgemische werden dann durch die Filtration in klaren Frucht- oder Obstsaft einerseits und die im wesentlichen verbleibenden Trübstoffe andererseits aufgetrennt. Dem Stoffgemisch kann beispielsweise vor der Filtration auch noch Aktivkohle zugesetzt werden, um bestimmte Wirkungen zu erzielen. Auch diese Aktivkohle muß dann mit den Trübstoffen von der Flüssigkeit abgetrennt werden.Such cross-flow filtration systems are used advantageously when it comes to molecularly disperse or colloidally disperse substance mixtures, at most with proportions of solid or To filter suspended solids. Examples of such mixtures of substances are mixtures of substances which initially arise in the production of fruit and fruit juices. These mixtures of substances are then separated by filtration into clear fruit or fruit juice on the one hand and the essentially remaining turbid substances on the other. For example, activated carbon can also be added to the mixture of substances before the filtration in order to achieve certain effects. This activated carbon must then also be separated from the liquid with the cloudy substances.
Eine Querstrom-Filtrationsanlage der im Oberbegriff des Anspruchs 1 genannten Art ist aus der WO-Al-01/51186 bekannt. Hierin wird eine Lösung gezeigt, wie Verstopfungen des Filtrationsmoduls durch feste Retentatanteile entfernt werden können. Bei Anlagen solcher Art besteht also das Problem, daß die Filterelemente verstopfen können, so daß die Produktion unterbrochen werden muß, um zunächst die Verstopfungen zu entfernen. Produktionsunterbrüche sind aber unerwünscht.A cross-flow filtration system of the type mentioned in the preamble of claim 1 is known from WO-Al-01/51186. A solution is shown here how blockages of the filtration module can be removed by fixed retentate portions. The problem with systems of this type is that the filter elements can become blocked, so that production has to be interrupted in order to first remove the blockages. Production interruptions are undesirable.
Aus JP-A-07 112 185 ist eine Abwasserbehandlungsvorrichtung bekannt, wobei auch ein Reinigungsverfahren unter Anwendung von komprimiertem Gas offenbart ist.A waste water treatment device is known from JP-A-07 112 185, and a cleaning method using compressed gas is also disclosed.
Aus JP-A-06226 065 ist ein Verfahren zur Reinigung von Membranfiltern bekannt. Dabei erfolgt die Reinigung durch Rückwärtsspülung unter Mitverwendung von Luft.A method for cleaning membrane filters is known from JP-A-06226 065. The cleaning is done by backwashing with the use of air.
Aus der schweizerischen Patentanmeldung 2242/01 ist es bekannt, während des Filtrationsvorgangs die Viskosität des Stoffgemischs zu überwachen. Damit kann erreicht werden, daß Verstopfungen gar nicht erst auftreten.It is known from Swiss patent application 2242/01 to monitor the viscosity of the mixture of substances during the filtration process. This means that constipation does not occur at all.
Aus WO-Al-00/03794 ist eine Filtrationsanlage bekannt, bei der nach Abschluß eines Filtrationszyklus über ein Ventil Spülwasser einspeisbar ist, das zur Verdrängung von hochviskosen Retentat-Resten aus der Filtereinheit dient. Durch eine solche Spülung kann das Verstopfen verhindert werden, wenn sie rechtzeitig eingeleitet wird. Die Einleitung der Spülung ist aber durchaus nicht unproblematisch, weil sich die Viskosität schnell ändert. Somit kann es trotz rechtzeitiger Einleitung einer Spülung zur Verblockung des Retentats in den Membranrohren des Filtrationsmoduls kommen.From WO-Al-00/03794 a filtration system is known in which, after the completion of a filtration cycle, rinse water can be fed in via a valve, which serves to displace highly viscous retentate residues from the filter unit. Such a flush can clogging can be prevented if initiated in good time. However, the initiation of the rinsing is not without problems because the viscosity changes quickly. Thus, despite the timely initiation of a rinse, the retentate can become blocked in the membrane tubes of the filtration module.
Aus der schweizerischen Patentanmeldung 0204/02 ist es bekannt, die Spülung so vorzunehmen, daß die schlagartige Veränderung der Viskosität verhindert wird.From Swiss patent application 0204/02 it is known to carry out the flushing in such a way that the sudden change in viscosity is prevented.
Es sind also verschiedene Ausgestaltungen von Querstrom-Filtrationsanlagen bekannt, die einen sicheren Betrieb ermöglichen. Grundsätzlich besteht aber das Problem, daß in solchen Anlagen enthaltene Filterelemente eine begrenzte Lebensdauer aufweisen. Eines der auftretenden Probleme dabei ist, daß Filterelemente Lecks bekommen können, so daß die Filtration nicht mehr fortgesetzt werden kann.Various configurations of cross-flow filtration systems are therefore known which enable safe operation. Basically, however, there is the problem that filter elements contained in such systems have a limited service life. One of the problems that arises is that filter elements can get leaks, so that the filtration can no longer continue.
Aus WO-Al -98/19778 sind Membranmodule für solche Querstrom-Filtrationsanlagen bekannt. Sie enthalten Rohrmembranen, die im Membranmodul in aufgewickelter, gebogener Form angeordnet sind. Eine Vielzahl solcher Membranmodule kann in der Querstrom-Filtrationsanlage parallel zueinander angeordnet sein. So sind beispielsweise aus WO-Al-01/51186 Anlagen bekannt, die 800 parallel geschaltete Membranrohre aufweisen.From WO-Al -98/19778 membrane modules for such cross-flow filtration systems are known. They contain tubular membranes, which are arranged in the membrane module in a wound, curved form. A large number of such membrane modules can be arranged parallel to one another in the crossflow filtration system. For example, systems are known from WO-Al-01/51186 which have 800 membrane tubes connected in parallel.
Ein Defekt eines einzelnen Membranrohres durch ein Leck führt dann dazu, daß die Filtration nicht mehr erfolgreich ist, weil das anfallende Permeat nicht mehr klar ist. Durch Einsatz eines Trübungssensors kann zwar erkannt werden, wenn dies der Fall ist, jedoch besteht dann das Problem, das defekte Membranrohr zu orten. Der Augenschein in der Weise, daß nach der Stelle mit der größten Trübung gesucht wird, ist in der Regel nicht zielführend.A defect in a single membrane tube due to a leak then leads to the filtration no longer being successful because the permeate obtained is no longer clear. By using a turbidity sensor, it can be recognized if this is the case, but there is then the problem of locating the defective membrane tube. A visual inspection in such a way that the place with the greatest cloudiness is searched for is usually not useful.
Der Erfindung liegt die Aufgabe zugrunde, eine Querstrom-Filtrationsanlage zu schaffen, die so beschaffen ist, daß mit ihr ein Verfahren zur Fehlerortung durchführbar ist.The invention has for its object to provide a cross-flow filtration system which is designed so that it can be used to carry out a method for fault location.
Die genannte Aufgabe wird erfindungsgemäß durch eine Querstrom-Filtrationsanlage mit den Merkmalen des Anspruchs 1 und durch ein Verfahren mit den Merkmalen des Anspruch 7 gelöst. Vorteilhafte Weiterbildungen ergeben sich aus den abhängigen Ansprüchen. Nachfolgend wird ein Ausfuhrungsbeispiel der Erfindung anhand der Zeichnung näher erläutert.The stated object is achieved according to the invention by a cross-flow filtration system with the features of claim 1 and by a method with the features of claim 7. Advantageous further developments result from the dependent claims. An exemplary embodiment of the invention is explained in more detail below with reference to the drawing.
Es zeigen:Show it:
Fig. 1 ein Schema einer Querstrom-Filtrationsanlage undFig. 1 is a schematic of a cross-flow filtration system and
Fig. 2 Einzelheiten eines Filterelements.Fig. 2 details of a filter element.
In der Fig. 1 bedeutet 1 ein Filterelement, in dem die Abtrennung der gewünschten flüssigen Phase aus dem Stoffgemisch erfolgt. Auf die Bauart des Filterelements 1 kommt es dabei nicht an. In erster Linie kommt die Erfindung dann zur Anwendung, wenn das Filterelement 1 beispielsweise gerade oder gewickelte Rohrmembranen oder Kapillarrohre enthält, da mit solchen Filterelementen 1 meistens Stoffgemische mit hohen Trübstoffanteilen verarbeitet werden. Tritt eine Verstopfung von Teilen des Filterelements 1 auf, so führt das regelmäßig zu einem Betriebsunterbruch mit all seinen nachteiligen Folgen.In FIG. 1, 1 means a filter element in which the desired liquid phase is separated from the mixture of substances. The design of the filter element 1 is not important. The invention is primarily used when the filter element 1 contains, for example, straight or wound tubular membranes or capillary tubes, since such filter elements 1 mostly process substance mixtures with high turbidities. If parts of the filter element 1 become blocked, this regularly leads to an interruption in operation with all its disadvantageous consequences.
Das zu filtrierende Stoffgemisch befindet sich in einem Produkttank 2. Von diesem gelangt es durch eine Zufuhrleitung 3 zum Filterelement 1. In die Zufülirleitung 3 sind eine Förderpumpe 4 und ein Durchflußmesser 5 eingesetzt, wobei die Drehzahl der Förderpumpe 4 durch den Durchflußmesser 5 in der Weise Steuer- bzw. regelbar ist, daß entweder die Förderleistung durch die Zufuhrleitung 3 oder der Druck in der Zufuhrleitung 3 am Eingang des Filterelements 1 konstant bleibt. Das ermöglicht in bekannter Weise eine wirtschaftliche Produktion.The mixture of substances to be filtered is located in a product tank 2. From there it passes through a feed line 3 to the filter element 1. A feed pump 4 and a flow meter 5 are inserted into the feed line 3, the speed of the feed pump 4 through the flow meter 5 in the manner It can be controlled or regulated that either the delivery rate through the supply line 3 or the pressure in the supply line 3 at the input of the filter element 1 remains constant. This enables economical production in a known manner.
Im Auslauf des Produkttanks 2, der in die Zufuhrleitung 3 mündet, befindet sich ein Tank- Absperrventil 6, das motorisch oder pneumatisch betätigbar ist. Auf der Sekundärseite des Filterelements 1 ist eine Permeatleitung 7 an dieses angeschlossen, durch die das im Filterelement 1 abgetrennte Permeat, also beispielsweise der klare Obstsaft, abgenommen werden kann.In the outlet of the product tank 2, which opens into the supply line 3, there is a tank shut-off valve 6 which can be actuated by a motor or pneumatically. On the secondary side of the filter element 1, a permeate line 7 is connected to it, through which the permeate separated off in the filter element 1, for example the clear fruit juice, can be removed.
Andererseits fuhrt vom Filterelement 1 eine Rückfuhrleitung 8 zum Produkttank 2. Darin wird das Retentat vom Filterelement 1 zum Produkttank 2 zurückgeführt. In diese Rückführleitung 8 ist ein Drosselventil 9 eingesetzt, das ebenfalls motorisch oder pneumatisch betätigbar ist. Dieses Drosselventil 9 ist von einem Retentatleitungs- Drucksensor 10 aus ansteuerbar, der den Druck am Retentat-Eingang des Filterelements 1 erfaßt. An der Rückfuhrleitung 8 kann unmittelbar hinter dem Filterelement 1 ein weiterer Retentatleitungs-Drucksensor 10' angeordnet sein. Der vom Retentatleitungs- Drucksensor 10 erfaßbare Druck in der Zuführleitung 3 unmittelbar vor dem Filterelemente 1 hängt mit der Förderleistung der Förderpumpe 4 und dem Zustand des Filterelements 1 zusammen. Je höher die Viskosität des Stoffgemisches ist, desto höher ist der Durchflußwiderstand. Eine Erhöhung der Viskosität kann beispielsweise durch einen erhöhten Anteil an Fest- oder Schwebstoffen im Stoffgemisch verursacht sein. In Abhängigkeit von diesem Durchtrittswiderstand kann nun das Drosselventil 9 motorisch oder pneumatisch mehr oder weniger geöffnet bzw. geschlossen werden. Vor der Einmündung der Rückführleitung 8 in den Produkttank 2 befindet sich ein Rückführleitungs-Absperrventil 11, das immer dann geöffnet ist, wenn das das Filterelement 1 verlassende Retentat zum Produkttank 2 zurückgeführt werden soll.On the other hand, a return line 8 leads from the filter element 1 to the product tank 2, in which the retentate is returned from the filter element 1 to the product tank 2. In this return line 8, a throttle valve 9 is inserted, which can also be actuated by a motor or pneumatically. This throttle valve 9 is from a retentate line Pressure sensor 10 controllable from, which detects the pressure at the retentate input of the filter element 1. A further retentate line pressure sensor 10 ′ can be arranged on the return line 8 directly behind the filter element 1. The pressure in the supply line 3 which can be detected by the retentate line pressure sensor 10 directly in front of the filter element 1 is related to the delivery capacity of the feed pump 4 and the state of the filter element 1. The higher the viscosity of the mixture of substances, the higher the flow resistance. An increase in viscosity can be caused, for example, by an increased proportion of solids or suspended matter in the mixture of substances. Depending on this penetration resistance, the throttle valve 9 can now be opened or closed more or less by motor or pneumatically. Before the return line 8 opens into the product tank 2 there is a return line shut-off valve 11 which is always open when the retentate leaving the filter element 1 is to be returned to the product tank 2.
Das im Produkttank 2 befindliche Stoffgemisch wird bei geöffnetem Tank- Absperrventil 6 mit Hilfe der Förderpumpe 4 zum Filterelement 1 gefördert. ImThe mixture of substances in the product tank 2 is conveyed to the filter element 1 with the aid of the feed pump 4 when the tank shut-off valve 6 is open. in the
Filterelement 1 wird aus dem Stoffgemisch Permeat abgeschieden. Das Retentat wird durch die Rückfuhrleitung 8 bei geöffnetem Rückführleitungs-Absperrventil 11 zum Produkttank 2 zurückgeführt. Dadurch erhöht sich im Laufe des Filtrationsprozesses die Viskosität des zirkulierenden Stoffgemisches, weil der Anteil an Fest- oder Schwebstoffen im Stoffgemisch immer weiter steigt, je mehr Permeat im Filterelement 1 abgeschieden worden ist. Gleichzeitig geht die Filtrationsleistung zurück. Hat die Viskosität des Stoffgemisches eine bestimmte Höhe erreicht, muß die Filtration beendet werden, und zwar so rechtzeitig, daß das Filterelement 1 nicht verstopfen kann. Das zirkulierende Stoffgemisch kann deshalb durch Öffnen eines Auslaßventils 12, das hinter dem Filterelement 1 angeordnet ist, aus dem Kreislauf abgenommen werden.Filter element 1 is separated from the permeate mixture. The retentate is returned to the product tank 2 through the return line 8 with the return line shut-off valve 11 open. As a result, the viscosity of the circulating mixture of substances increases in the course of the filtration process, because the proportion of solid or suspended substances in the mixture of substances increases the more permeate has been separated in filter element 1. At the same time, the filtration performance drops. When the viscosity of the mixture of substances has reached a certain level, the filtration must be stopped, and in good time so that the filter element 1 cannot become blocked. The circulating mixture of substances can therefore be removed from the circuit by opening an outlet valve 12 which is arranged behind the filter element 1.
Soll der Filtrationsvorgang begonnen werden, so wird dem Produkttank 2 zunächst über eine Produktleitung 13 das zu filtrierende Stoffgemisch zugeführt. Die Förderpumpe 4 geht dann in Betrieb. Anfangs ist das im Produkttank 2 enthaltene Stoffgemisch relativ niederviskos. Die Förderpumpe 4 wird so geregelt, daß die Förderleistung durch die Zufuhrleitung 3 konstant bleibt. Im Filterelement 1 wird Permeat abgetrennt, so daß das das Filterelement 1 verlassende Retentat eine höhere Viskosität aufweist. Dieses Retentat wird wieder dem Produkttank 2 zugeführt. Dessen Menge ist wegen der Abscheidung von Permeat im Filterelement 1 kleiner. Zum Ausgleich wird durch die Produktleitung 13 weiteres Stoffgemisch zugeführt. Mit fortschreitender Dauer des Prozesses steigt so die Viskosität des im Produkttank 2 befindlichen Stoffgemisches immer weiter an. Das fuhrt dann dazu, daß dann, wenn die Förderpumpe 4 die Förderleistung durch die Zufuhrleitung 3 konstant hält, der mit dem Retentatleitungs-Drucksensor 10 erfaßbare Druck ansteigt. Weil dieser Druck im Hinblick auf die Belastbarkeit des Filterelements 1 einen bestimmten Grenzwert nicht überschreiten darf, wird dann die Förderpumpe 4 so geregelt, daß dieser Grenzwert nicht überschritten wird. Die Filtrationsleistung geht dann zurück.If the filtration process is to be started, the mixture of substances to be filtered is first fed to the product tank 2 via a product line 13. The feed pump 4 then goes into operation. Initially, the mixture of substances contained in the product tank 2 is relatively low-viscosity. The feed pump 4 is controlled so that the delivery rate through the supply line 3 remains constant. Permeate is separated off in the filter element 1, so that the retentate leaving the filter element 1 has a higher viscosity. This retentate is returned to the product tank 2. Its amount is due to the deposition of Permeate in filter element 1 smaller. To compensate, 13 additional substance mixture is fed through the product line. As the process progresses, the viscosity of the mixture of substances in the product tank 2 increases further and further. This leads to the fact that when the feed pump 4 keeps the delivery rate through the supply line 3 constant, the pressure that can be detected by the retentate line pressure sensor 10 increases. Because this pressure must not exceed a certain limit value with regard to the load capacity of the filter element 1, the feed pump 4 is then regulated so that this limit value is not exceeded. The filtration performance then drops.
Dadurch wird dann ein Zustand erreicht, daß die Filtrationsleistung zu klein für einen wirtschaftlichen Betrieb wird und schließlich auch nicht mehr sicher ist. Dann soll die Filtration beendet werden. Ein Abstellen der Förderpumpe 4 der Filtrationsanlage darf nun aber nicht erfolgen, weil dies unweigerlich zur einer Verstopfung führen würde. Es ist jetzt nötig, das in der Anlage befindliche Stoffgemisch aus dieser zu verdrängen. Dies geschieht in bekannter Weise durch Spülen. Damit das auf der Sekundärseite desThis then leads to a condition that the filtration capacity becomes too low for economical operation and is ultimately no longer safe. Then the filtration should be ended. However, the feed pump 4 of the filtration system must not be switched off because this would inevitably lead to a blockage. It is now necessary to displace the mixture of substances in the system. This is done in a known manner by rinsing. So that on the secondary side of the
Filterelements 1 befindliche Produkt, das Permeat, nicht durch Spülwasser verdünnt wird, wird es vor Beginn des Spülvorgangs abgelassen.Filter element 1 located product, the permeate, is not diluted by rinsing water, it is drained before the start of the rinsing process.
Deshalb ist ein Spülwassertank 14 vorhanden, aus dem Spülwasser durch eine Spülleitung 15 in die Zuführleitung 3 eingespeist werden kann. Im Zuge der Spülleitung 15 ist ein Spülleitungs-Absperrventil 16 eingesetzt. Zwischen dem Spülwassertank 14 und dem Spülleitungs-Absperrventil 16 ist noch ein Element angeordnet, dessen Aufgabe es ist, zu verhindern, daß beim Öffnen des Spülleitungs- Absperrventils 16 nennenswerte Mengen des Stoffgemischs aus der Zuführleitung 3 zum Spülwassertank 14 zurückströmen. Beim Übergang vom Filtrations- zum Spülvorgang wird mehr oder weniger gleichzeitig das Tank- Absperrventil 6 geschlossen und dasTherefore, a rinse water tank 14 is provided, from which rinse water can be fed into the feed line 3 through a rinse line 15. In the course of the flush line 15, a flush line shut-off valve 16 is used. Between the rinse water tank 14 and the rinse line shut-off valve 16 there is another element, the task of which is to prevent significant amounts of the substance mixture from flowing back from the feed line 3 to the rinse water tank 14 when the rinse line shut-off valve 16 is opened. During the transition from the filtration to the flushing process, the tank shut-off valve 6 is closed more or less simultaneously and that
Spülleitungs-Absperrventil 16 geöffnet. Das Tank- Absperrventil 6 und das Spülleitungs- Absperrventil 16 werden von einem Steuergerät 20, mit dem der Filtrationsprozeß steuerbar ist, betätigt. Beim mehr oder weniger gleichzeitigen Öffnen des Spülleitungs- Absperrventils 16 und Schließen des Tank- Absperrventils 6 könnte infolge eines Niveau- Unterschieds H zwischen dem Inhalt im Produkttank 2 und dem Inhalt imFlush line shut-off valve 16 opened. The tank shut-off valve 6 and the flushing line shut-off valve 16 are actuated by a control unit 20, with which the filtration process can be controlled. When the flushing line shut-off valve 16 is opened more or less simultaneously and the tank shut-off valve 6 is closed, a difference in level H between the content in the product tank 2 and the content in
Spülwassertank 14 dann Stoffgemisch aus dem Produkttank 2 zum Spülwassertank 14 strömen, wenn der Niveau-Unterschied H eine bestimmte Größe hat, wobei auch zu berücksichtigen ist, daß die Dichte im Produkttank 2 größer ist als jene des Spülwassers im Spülwassertank 14. Dieses Eindringen nennenswerter Mengen des Stoffgemischs in Richtung zum Spül Wassertank 14 wird durch das erwähnte Element verhindert. Da bei bekannten Filtrationsanlagen die Spülleitung 15 meist mehrere Meter lang ist, bleibt der Spülwassertank 14 vom Eindringen von Stoffgemisch verschont. Das im Spülwassertank 14 enthaltene Wasser wird also nicht verschmutzt.Rinse water tank 14 then flow mixture of substances from product tank 2 to rinse water tank 14 if the difference in level H has a certain size, also increasing take into account that the density in the product tank 2 is greater than that of the rinse water in the rinse water tank 14. This penetration of significant amounts of the mixture of substances in the direction of the rinse water tank 14 is prevented by the element mentioned. Since the rinsing line 15 is usually several meters long in known filtration systems, the rinsing water tank 14 is spared from the ingress of substance mixture. The water contained in the rinse water tank 14 is therefore not contaminated.
Dieses den Stoffgemisch-Rückfluß verhindernde Element ist entweder ein Rückschlagventil 17 oder eine Rückflußdrossel 17', wie dies aus der schweizerischen Patentanmeldung 0204/02 bekannt ist.This element preventing the mixture reflux is either a check valve 17 or a reflux throttle 17 ', as is known from the Swiss patent application 0204/02.
Am Ende eines zuvor geschilderten Produktionszyklus befindet sich im Filterelement 1 Spülwasser. Nun kann die Querstrom-Filtrationsanlage abgestellt werden. Dann können auch Wartungsarbeiten durchgeführt werden.At the end of a previously described production cycle, there is 1 rinsing water in the filter element. The cross-flow filtration system can now be switched off. Maintenance work can then also be carried out.
Eine solche Querstrom-Filtrationsanlage läßt sich also sehr sicher und wirtschaftlich betreiben. Im Normalbetrieb ist das Verblocken des Filterelements 1 mit Sicherheit auszuschließen. Es besteht aber das Problem, daß während des Betriebs ein Defekt im Filterelement 1 auftreten kann. Ein Leck in einem der Membranrohre des Filterelements 1 f hrt dann dazu, daß das Permeat nicht mehr klar ist. Es ist dann erforderlich, die Anlage stillzusetzen, um das defekte Element auswechseln zu können. Wie eingangs erwähnt, ist das Erkennen des Ortes des Defekts durchaus problematisch.Such a cross-flow filtration system can therefore be operated very safely and economically. In normal operation, blocking of the filter element 1 can be excluded with certainty. However, there is the problem that a defect can occur in the filter element 1 during operation. A leak in one of the membrane tubes of the filter element 1 then leads to the permeate being no longer clear. It is then necessary to shut down the system in order to be able to replace the defective element. As mentioned at the beginning, recognizing the location of the defect is problematic.
Erfindungsgemäß ist deshalb vorgesehen, daß in die Zuführleitung 3 zum Filterelement 1 eine Druckluftleitung 25 einmündet, die von einem Druckluft-Absperrventil 26 absperrbar ist. Durch das Öffnen des Druckluft- Absperrventils 26 wird das im Filterelement 1 befindliche Spülwasser mittels Druckluft aus dem Filterelement 1 verdrängt. Damit die Druckluft nicht in die Zuführleitung 3 und die darin angeordnete Förderpumpe 4 und den Durchflußmesser 5 eindringt, ist es zudem erforderlich, in der Nähe des Filterelements 1 in der Zufuhrleitung 3 ein Zufuhrleitungs- Absperrventil 28 anzuordnen.According to the invention it is therefore provided that a compressed air line 25 opens into the supply line 3 to the filter element 1 and can be shut off by a compressed air shut-off valve 26. By opening the compressed air shut-off valve 26, the flushing water located in the filter element 1 is displaced from the filter element 1 by means of compressed air. So that the compressed air does not penetrate into the feed line 3 and the feed pump 4 and the flow meter 5 arranged therein, it is also necessary to arrange a feed line shut-off valve 28 in the vicinity of the filter element 1 in the feed line 3.
Das aus der schweizerischen Patentanmeldung 0204/02 bekannte Auslaßventil 12 ist vorteilhaft unmittelbar hinter dem Filterelement 1 angeordnet, wie dies in der Fig. 1 gezeigt ist. Ist das Retentat bzw. das Spülwasser aus dem Filterelement 1 verdrängt, ist der Primärkreis des Filterelements 1 mit Luft gefüllt. Weist eines der Einzelteile des Filterelements 1 ein Leck auf, so wird durch dieses Leck Luft in den Sekundärkreis des Filterelements 1 durchtreten. Durch Augenschein kann nun sehr einfach der genauer Ort des Lecks erkannt werden. Um ein Leck im Filterelement 1 erkennen zu können, ist es vorteilhaft, wenn der Druck der Luft im Filterelement 1 langsam erhöht wird. Um eine solche langsame Druckänderung möglich zu machen, ist vorteilhaft zwischen dem Druckluft-Absperrventil 26 und der Einmündung der Druckluftleitung 25 in die Zufuhrleitung 3 eine verstellbare Drossel 27 angeordnet. Damit ist es möglich, den auf das Filterelement 1 wirkenden Luftdruck langsam zu erhöhen. Dann ist sehr leicht zu beobachten, an welcher Stelle des Filterelements 1 Luft austritt. Damit ist der Ort des Defekts lokalisiert. Die Anlage kann nun stillgesetzt werden und die Beseitigung des Defekts durch Austausch des defekten Teils eingeleitet werden.The outlet valve 12 known from the Swiss patent application 0204/02 is advantageously arranged directly behind the filter element 1, as shown in FIG. 1. If the retentate or the rinsing water is displaced from the filter element 1, the primary circuit of the filter element 1 is filled with air. If one of the individual parts of the filter element 1 has a leak, air will pass through this leak into the secondary circuit of the filter element 1. Visually, the exact location of the leak can now be recognized very easily. In order to be able to recognize a leak in the filter element 1, it is advantageous if the pressure of the air in the filter element 1 is slowly increased. In order to make such a slow pressure change possible, an adjustable throttle 27 is advantageously arranged between the compressed air shut-off valve 26 and the confluence of the compressed air line 25 into the supply line 3. It is thus possible to slowly increase the air pressure acting on the filter element 1. Then it is very easy to observe at which point of the filter element 1 air emerges. The location of the defect is thus localized. The system can now be shut down and the defect can be remedied by replacing the defective part.
Anfangs befindet sich aber noch Spülwasser im Filterelement 1. Zur Durchführung der Leckprüfung muß dieses Spülwasser zunächst praktisch vollständig aus demInitially, however, there is still rinsing water in the filter element 1. In order to carry out the leak test, this rinsing water must first be virtually completely out of the
Filterelement 1 verdrängt werden. Mit langsam steigendem Druck der Luft ist dies aber nicht möglich, insbesondere dann, wenn das Filterelement 1 mehrere parallel geschaltete Membranmodule enthält, was noch gezeigt wird.Filter element 1 are displaced. However, this is not possible with a slowly increasing pressure of the air, especially if the filter element 1 contains a plurality of membrane modules connected in parallel, as will be shown.
So ist es vorteilhaft, zunächst unter Anwendung eines möglichst hohen Luftdrucks das Spülwasser aus dem Filterelement 1 zu verdrängen. Anschließend wird der Druck wieder reduziert und nun langsam gesteigert. Das Verdrängen des Spülwassers aus dem Filterelement 1 geschieht mit einem Druck knapp unterhalb der Belastungsgrenze des Filterelements 1, die beispielsweise 6 bar beträgt. Das Verdrängen des Spülwassers erfolgt bei einem Druck von etwa 3 bis 6 bar. Anschließend wird der Druck reduziert und schließlich wieder langsam gesteigert, beispielsweise zunächst auf 1 bar und dann langsam weiter auf 2 bar. Ist das Filterelement 1 defekt, ist der sogenannte bubble point, also der Druck, bei dem Luft austritt, in diesem Druckbereich 1 bis 2 bar erreicht.So it is advantageous to first displace the rinsing water from the filter element 1 using the highest possible air pressure. Then the pressure is reduced again and slowly increased. The flushing water is displaced from the filter element 1 at a pressure just below the load limit of the filter element 1, which is, for example, 6 bar. The flushing water is displaced at a pressure of approximately 3 to 6 bar. The pressure is then reduced and finally slowly increased again, for example first to 1 bar and then slowly to 2 bar. If the filter element 1 is defective, the so-called bubble point, ie the pressure at which air emerges, has reached 1 to 2 bar in this pressure range.
Um die Handhabung zu erleichtern, kann vorteilhaft parallel zur verstellbaren Drossel 27 ein schaltbares AUF-ZU- Ventil 29 angeordnet sein, wie dies in der Fig. 1 durch gestrichelte Linien gezeigt ist. In diesem Fall wird vorteilhaft wie folgt vorgegangen.In order to facilitate handling, a switchable OPEN-CLOSE valve 29 can advantageously be arranged parallel to the adjustable throttle 27, as is shown in FIG. 1 by dashed lines. In this case, the procedure is advantageously as follows.
Nach dem Öffnen des Druckluft-Absperrventils 26 wird das AUF-ZU- Ventil 29 geöffnet und dadurch wird unter Anwendung eines Luftdrucks von etwa 3 bis 6 bar das Spülwasser aus dem Filterelement 1 schnell und vollständig verdrängt. Danach wird das AUF-ZU- Ventil 29 wieder geschlossen. Daran anschließend kann nun mit Hilfe der verstellbaren Drossel 27 der Luftdruck langsam bis zum Erreichen des bubble point gesteigert werden.After opening the compressed air shut-off valve 26, the OPEN-CLOSE valve 29 is opened and thereby the rinsing water from the filter element 1 is quickly and completely displaced using an air pressure of about 3 to 6 bar. Then the OPEN-CLOSE valve 29 is closed again. Then, with the help of the adjustable throttle 27, the air pressure can be slowly increased until the bubble point is reached.
Diese Variante ist deshalb vorteilhaft, weil es mittels einer verstellbaren Drossel 27 nicht möglich ist, den Druck sehr schnell zu erhöhen, wie dies zum annähernd vollständigen Verdrängen des Spülwassers aus dem Filterelement 1 nötig ist.This variant is advantageous because it is not possible to increase the pressure very quickly by means of an adjustable throttle 27, as is necessary to almost completely displace the rinsing water from the filter element 1.
Vorteilhaft weist die Druckluftleitung 25 einen Speicher 32 auf. Dadurch steht eine genügend große Menge an Druckluft in unmittelbarer Nähe der Querstrom- Filtrationsanlage zur Verfügung. Vielfach besteht nämlich das Problem, daß im Betrieb vorhandene Druckluftleitungen keinen großen Querschnitt aufweisen und relativ lang sind. Um nun zu garantieren, daß das Ausblasen des Filterelements 1 vollständig und zügig erfolgt, ist dieser Speicher 32 vorteilhaft. Die Größe des Speichers 32 richtet sich nach den Gegebenheiten der Querstrom-Filtrationsanlage, nämlich insbesondere nach den Dimensionen des Filterelements 1.The compressed air line 25 advantageously has a memory 32. This means that a sufficient amount of compressed air is available in the immediate vicinity of the cross-flow filtration system. In fact, there is often the problem that compressed air lines which are in operation do not have a large cross section and are relatively long. This memory 32 is advantageous in order to guarantee that the filter element 1 is blown out completely and quickly. The size of the store 32 depends on the conditions of the cross-flow filtration system, namely in particular on the dimensions of the filter element 1.
Erwähnt sei hier, daß einzelne Leitungsteile am Filterelement 1 durchaus so großvolumig sein können, daß auch diese Leitungsteile als Speicher 32 wirken können.It should be mentioned here that individual line parts on the filter element 1 can be of such a large volume that these line parts can also act as a memory 32.
Aus Gründen der Übersichtlichkeit sind in der Fig. 1 vom Steuergerät 20 zum Druckluft- Absperrventil 26 und zum Zufuhrleitungs- Absperrventil 28 führende Steuerleitungen nicht eingezeichnet.For reasons of clarity, control lines leading from the control unit 20 to the compressed air shutoff valve 26 and to the supply line shutoff valve 28 are not shown in FIG. 1.
Vorteilhaft weist die Druckluft im Speicher 32 einen Druck von mindestens 3 bar auf. Die Obergrenze für den Druck ist gegeben durch die Belastungsgrenze für das Filterelement 1, die beispielsweise etwa 6 bar betragen kann.The compressed air in the accumulator 32 advantageously has a pressure of at least 3 bar. The upper limit for the pressure is given by the load limit for the filter element 1, which can be approximately 6 bar, for example.
Steht kein leistungsfähiges Druckluftsystem zur Verfügung, kann anstelle der Druckluft auch ein anderes Druckgas verwendet werden, beispielsweise Stickstoff, das aus einer Hochdruckflasche 34 entnehmbar ist. Der Speicher 32 wird dann aus dieser Hochdruckflasche 34 mit Druckgas versorgt, was mittels eines Druckreduzierventils 35 ohne Zufuhr äußerer Energie selbsttätig erfolgen kann. In der Fig. 2 ist in Sinne eines Beispiels ein Filterelement 1 gezeigt, wie es prinzipiell aus WO-Al -01/51186 bekannt ist. Gleiche Bezugszahlen bedeuten dabei gleiche Elemente wie in der Fig. 1. Das Filterelement 1 enthält eine Vielzahl von Membranmodulen 40, die parallel zueinander zwischen der Zuführleitung 3 und der Rückführleitung 8 angeordnet sind. Wird, wie zuvor erwähnt, das Filterelement 1 von der Druckluftleitung 25 her mit Druckluft beaufschlagt, so ist ein Leck in einem der Membranmodule 40 sehr leicht daran erkennbar, daß vom Ort des Lecks durch die im Filterelement 1 befindliche Flüssigkeit Blasen 41 aufsteigen. Damit ist der Ort des Defekts leicht feststellbar. Das defekte Membranmodul 40 kann so leicht gefunden und dann ausgetauscht werden.If no powerful compressed air system is available, another compressed gas can be used instead of the compressed air, for example nitrogen, which can be removed from a high pressure bottle 34. The reservoir 32 is then supplied with compressed gas from this high-pressure bottle 34, which can be done automatically by means of a pressure reducing valve 35 without the supply of external energy. In the sense of an example, FIG. 2 shows a filter element 1, as is known in principle from WO-Al-01/51186. The same reference numerals mean the same elements as in FIG. 1. The filter element 1 contains a large number of membrane modules 40 which are arranged parallel to one another between the feed line 3 and the return line 8. If, as mentioned above, the filter element 1 is pressurized with compressed air from the compressed air line 25, a leak in one of the membrane modules 40 can be recognized very easily by the fact that bubbles 41 rise from the location of the leak due to the liquid in the filter element 1. This makes it easy to determine the location of the defect. The defective membrane module 40 can thus be found easily and then exchanged.
Es kann vorkommen, daß ein Defekt des Filterelements 1 gleich zu Beginn einesIt can happen that a defect of the filter element 1 right at the beginning of a
Produktionszyklus auftritt, dann also, wenn die Viskosität des Retentats noch gering ist, so daß es möglich ist, direkt das Retentat mittels Druckluft aus dem Filterelement 1 zu verdrängen. Die Spülung vor Beginn der Lecksuche mittels Druckluft ist dann nicht nötig.Production cycle occurs, that is, when the viscosity of the retentate is still low, so that it is possible to directly displace the retentate from the filter element 1 by means of compressed air. Flushing with compressed air before the start of the leak search is then not necessary.
Dabei kann es dann aber vorkommen, daß durch die defekte Stelle Luft zunächst gar nicht austritt, so daß der Ort des Fehlers nicht gefunden werden kann. Das kann dann der Fall sein, wenn der Filtrationsprozeß schon eine gewisse Zeit gelaufen ist und sich deshalb die Viskosität des Stoffgemischs etwas erhöht hat. Auf der Innenwand der Membranrohre des Filterelements 1 haben sich dann schon gewisse Mengen von Feststoffen abgesetzt, die den Durchtritt von Luft verhindern können. Weil aber durch das Auftreten einer Trübung des Permeats ein Leck vorhanden sein muß, ist es in einem solchen Fall angezeigt, das Filterelement 1 nun doch erst mittels Spülwasser so durchzuspülen, daß die abgesetzten Feststoffe ausgeschwemmt werden. Dazu wird das Druckluft- Absperrventil 26 wieder geschlossen und das Zuführleitungs-Absperrventil 28 geöffnet. Dann wird in bekannter Weise die Spülung des Filterelements 1 durchgeführt. Darauf folgt dann in der beschriebenen Weise die Verdrängung de Spülwassers aus dem Filterelement 1 und dann die Lecksuche mit langsam steigenden Luftdruck. However, it can then happen that air does not initially escape through the defective location, so that the location of the fault cannot be found. This can be the case if the filtration process has been running for a certain time and the viscosity of the mixture of substances has therefore increased somewhat. On the inner wall of the membrane tubes of the filter element 1, certain amounts of solids have already settled, which can prevent the passage of air. However, because a leak must be present due to the occurrence of a clouding of the permeate, it is advisable in such a case to rinse the filter element 1 with rinsing water only so that the settled solids are flushed out. For this purpose, the compressed air shutoff valve 26 is closed again and the supply line shutoff valve 28 is opened. Then the filter element 1 is rinsed in a known manner. This is followed in the manner described, the displacement of the rinse water from the filter element 1 and then the leak detection with slowly increasing air pressure.

Claims

Patentansprüche claims
1. Querstrom-Filtrationsanlage mit mindestens einem Filterelement (1), dem Stoffgemisch aus einem Produkttank (2) durch eine Zuführleitung (3) zuführbar ist, wobei zwischen dem Produkttank (2) und der Zufuhrleitung (3) ein Tank- Absperrventil (6) angeordnet ist, und bei der aus einem Spülwassertank (14) über eine Spülleitung (15) und ein Spülleitungs-Absperrventil (16) Spülwasser in die Zufuhrleitung (3) zufuhrbar ist, dadurch gekennzeichnet,1. Cross-flow filtration system with at least one filter element (1), the substance mixture from a product tank (2) can be fed through a feed line (3), a tank shut-off valve (6) between the product tank (2) and the feed line (3) and in which rinsing water can be fed into the supply line (3) from a rinsing water tank (14) via a rinsing line (15) and a rinsing line shut-off valve (16), characterized in that
- daß vor dem Eintritt der Zufülirleitung (3) in das Filterelement (1) ein Zuführleitungs- Absperrventil (28) angeordnet ist und daß eingangsseitig am Filterelement (1) eine Druckluftleitung (25) einmündet, die von einem Druckluft- Absperrventil (26) absperrbar ist.- That before the inlet of the feed line (3) in the filter element (1) a supply line shut-off valve (28) is arranged and that on the input side of the filter element (1) a compressed air line (25) opens, which can be shut off by a compressed air shut-off valve (26) is.
2. Querstrom-Filtrationsanlage nach Anspruch 1, dadurch gekennzeichnet, daß in jenem Abschnitt der Druckluftleitung (25) zwischen dem Druckluft- Absperrventil (26) und der Einmündung der Druckluftleitung (25) in die Zuführleitung (3) eine verstellbare Drossel (27) angeordnet ist, mit der der Druck veränderbar ist.2. Cross-flow filtration system according to claim 1, characterized in that in that section of the compressed air line (25) between the compressed air shut-off valve (26) and the confluence of the compressed air line (25) in the supply line (3) an adjustable throttle (27) is arranged with which the pressure can be changed.
3. Querstrom-Filtrationsanlage nach Anspruch 2, dadurch gekennzeichnet, daß der Drossel (27) ein schaltbares AUF-ZU- Ventil (29) parallel geschaltet ist.3. cross-flow filtration system according to claim 2, characterized in that the throttle (27) is a switchable OPEN-CLOSE valve (29) is connected in parallel.
4. Querstrom-Filtrationsanlage nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß in der Druckluftleitung (25) ein Speicher (32) angeordnet ist.4. Cross-flow filtration system according to one of claims 1 to 3, characterized in that a memory (32) is arranged in the compressed air line (25).
5. Querstrom-Filtrationsanlage nach Anspruch 4, dadurch gekennzeichnet, daß der Speicher (32) auf einen Druck von mindestens 3 bar aufladbar ist.5. cross-flow filtration system according to claim 4, characterized in that the memory (32) can be charged to a pressure of at least 3 bar.
6. Querstrom-Filtrationsanlage nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß der Speicher (32) über ein Druckreduzierventil (35) aus einer Hochdruckflasche (34) mit Druckgas versorgbar ist.6. cross-flow filtration system according to one of claims 1 to 5, characterized in that the memory (32) via a pressure reducing valve (35) from a high pressure bottle (34) can be supplied with compressed gas.
7. Verfahren zur Fehlerortung bei einer Querstrom-Filtrationsanlage nach Anspruch 1 , dadurch gekennzeichnet, daß das Zuführleitungs-Absperrventil (28) geschlossen und das Druckluft- Absperrventil (26) geöffnet wird, wodurch mittels Druckluft das Retentat oder das Spülwasser aus dem Filterelement (1) verdrängt wird. 7. A method for fault location in a cross-flow filtration system according to claim 1, characterized in that the supply line shut-off valve (28) is closed and the compressed air shut-off valve (26) is opened, whereby the retentate or the rinsing water from the filter element (1 ) is displaced.
8. Verfahren nach Anspruch 7, dadurch gekennzeichnet, daß anschließend in bekannter Weise Feststoffe aus dem Filterelement (1) ausgewaschen werden, indem dem Filterelement (1) Spülwasser aus dem Spülwassertank (14) zugeführt wird.8. The method according to claim 7, characterized in that subsequently solids are washed out of the filter element (1) in a known manner by the filter element (1) flushing water from the flushing water tank (14) is supplied.
9. Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß nach dem Beenden des Spülens des Filterelements (1) und dem Verdrängen des Spülwassers mittels Druckluft diesem wiederum Druckluft zugeführt wird, wobei der Druck mittels einer verstellbaren Drossel (27) langsam gesteigert wird. 9. The method according to claim 8, characterized in that after the rinsing of the filter element (1) and the displacement of the rinsing water by means of compressed air, this in turn is supplied with compressed air, the pressure being slowly increased by means of an adjustable throttle (27).
EP03746211A 2002-04-12 2003-03-25 Cross flow filtration system and method for locating defects Withdrawn EP1494788A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CH6142002 2002-04-12
CH614022002 2002-04-12
PCT/CH2003/000196 WO2003086593A1 (en) 2002-04-12 2003-03-25 Cross flow filtration system and method for locating defects

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CN (1) CN1646211A (en)
AU (1) AU2003210114A1 (en)
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WO (1) WO2003086593A1 (en)

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RU2338433C2 (en) * 2004-02-18 2008-11-20 Бухер Гиер АГ Method of product diafiltration and device for implementation of method

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JPH05212254A (en) * 1992-02-04 1993-08-24 Toray Ind Inc Hollow-fiber membrane module filter
JPH0623246A (en) * 1992-07-07 1994-02-01 Hitachi Plant Eng & Constr Co Ltd Method for washing membrane
JPH07112185A (en) * 1993-08-26 1995-05-02 Nitto Denko Corp Waste water treating device and washing method therefor
JP2000024659A (en) * 1998-07-09 2000-01-25 Daicel Chem Ind Ltd Solid-liquid separator and its operation

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WO2003086593A1 (en) 2003-10-23
PL370707A1 (en) 2005-05-30
AU2003210114A1 (en) 2003-10-27

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