JP2005185944A - Filter membrane breakage detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter membrane breakage detection apparatus surely detecting breakage of the membrane of a filter unit 1 without intermitting filtering operation at a low cost. <P>SOLUTION: The filter unit 1 filtering raw water through the filter membrane is provided with a filter 5 visible from outside at a flow passage of filtered water T filtered from the raw water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a filtration membrane breakage detection device for detecting breakage of a filtration membrane in a filtration device that filters raw water through a filtration membrane such as a hollow fiber membrane.

As this type of filtration membrane breakage detection device, for example, Patent Document 1 discloses a filter membrane breakage by measuring the turbidity of filtered water filtered by a filtration membrane such as a hollow fiber membrane or the number of particles in the filtered water. What to detect is described. Patent Documents 2 and 3 also propose a method of detecting breakage of the filtration membrane by supplying gas to the filtration membrane of the filtration device and detecting the leakage.
JP 2001-343320 A JP-A-8-10590 JP-A-5-157654

  However, among these, in the detection device described in Patent Document 1, the measurement device itself such as a turbidimeter and a particle counter for measuring turbidity and the number of particles is expensive. Therefore, a membrane module in which hollow fiber membranes are bundled in a filtration device If there are a large number of such devices, it would be extremely expensive to equip all of these measuring devices, so measurement can only be performed at the location of the collective drainage pipes where the drainage pipes for filtered water are collected. Even if breakage is detected, it is difficult to detect which membrane module's filtration membrane is broken.

  On the other hand, in the detection devices described in Patent Documents 2 and 3 that supply gas to the filtration membrane, the raw water filtration operation of the filtration device must be interrupted during detection. And the complicated operation | work which replaces all the water in a hollow fiber membrane with air and replaces with water again is needed. In addition, since it is necessary to provide supply means for supplying gas to every membrane module of the filtration device, it is possible to avoid an increase in cost for a filtration device having a large number of membrane modules. Absent.

  The present invention has been made under such a background. Filtration capable of reliably detecting a filtration membrane breakage in a filtration device at a low cost without interrupting the filtration operation. An object of the present invention is to provide a film breakage detection device.

  In order to solve the above-described problems and achieve such an object, the present invention provides a filter that is filtered from the raw water in a filtration device that filters the raw water through a filtration membrane, and a filter that is visible from the outside. It is characterized by being provided.

  In the above-described breakage detection device, when breakage occurs in the filtration membrane, turbidity is mixed into the filtered water, flows into the flow path together with the filtered water, is captured by the filter, and gradually accumulates on the filter. . That is, the filter that is visible from the outside is gradually soiled by the flow of filtered water, so that it can be reliably detected visually without missing any damage during the filtration operation. Moreover, such a filter is extremely inexpensive compared to a measuring device such as a turbidimeter, a particle counter or the like and a gas supply means for each filtration membrane. For example, all filtration of a large number of membrane modules is possible. The filter can be provided in the water flow path, and it is possible to quickly detect which membrane module of the membrane is damaged.

  Here, when the filtration device is a device that filters a large amount of raw water and discharges a large amount of filtered water, such as a filtration device in a water purification plant or a sewage treatment plant, for example, When it is difficult to provide a filter in the water drain pipe itself, a branch pipe having a smaller cross section than the drain pipe is provided as a flow path for the filtered water and is branched from the drain pipe. However, even if such a branch pipe is provided, it is far less expensive than a measuring device such as a turbidimeter or particle counter, or a gas supply means. In addition, since the running cost is low, it is possible to provide the above-mentioned filter by providing branch pipes in all the drain pipes such as a large number of membrane modules. In addition, when providing a branch pipe in this way, by providing a throttling or a venturi in the drain pipe facing the connecting portion with the branch pipe, filtered water can always flow into the branch pipe. Reliable detection can be achieved.

  On the other hand, the filter is not particularly limited as long as it is visible from the outside and can visually confirm dirt due to turbidity in the filtered water. For example, the filter has a planar shape facing the flow direction of the filtered water in the flow path. The filtered water flowing through the flow path can be obtained by being housed in a housing in which all or part of the filter is transparent and capable of observing the filter and interposed in the flow path of the filtered water. The turbidity can be captured by filtering on the entire surface of the plane, and it becomes possible to detect the breakage of the filtration membrane more reliably. The filter has a filter pore diameter of 1 μm or more so as not to increase the pressure loss, and preferably 1 to 20 μm in order to catch turbidity.

  1 and 2 show an embodiment of the present invention. The filtration device 1 of this embodiment is for filtering raw water from which sludge and the like are removed, for example, in a sewage treatment plant, and a membrane module 2 in which a plurality of filtration membranes in which hollow fiber membranes are bundled is accommodated in a casing. As shown in FIG. 1, a plurality of elements having a hollow fiber membrane stretched in a screen shape or a plurality of elements having a flat membrane-like separation membrane are stacked or a plurality of tubular ceramic membrane elements are bundled. The filtration membrane is also housed in a casing or immersed in a filtration tank, and the raw water introduced into the membrane module 2, the casing, and the filtration tank is filtered through such a filtration membrane to be clarified. The filtered water T is discharged.

  Further, drain pipes 3 for discharging the filtered water T thus filtered are connected to the plurality of membrane modules 2 and elements, respectively. These drain pipes 3 are collective drainage having a large cross section (large inner diameter). The drainage pipe 3 and the collective drainage pipe 4, which are collected in the pipe 4, form a flow path for discharging the filtered water T filtered from the raw water by the filtration device 1. And the membrane breakage detection apparatus of the filtration apparatus 1 of this embodiment is equipped in the collective drainage pipe 4 with this big cross section.

  More specifically, the collective drain pipe 4 is branched from the collective drain pipe 4 and then communicated with the collective drain pipe 4 again on the downstream side in the flow direction F of the filtered water T in the collective drain pipe 4. A branch pipe 6 having a small inner diameter smaller than that of the collective drain pipe 4 is connected, and the flow path of the filtered water T flowing further branched from the collective drain pipe 4 is constituted by the branch pipe 6. And in the film | membrane breakage detection apparatus of this embodiment, the filter 5 is interposed in the middle of the said branch pipe 6 which comprises the flow path of the filtrate T in this way, This filter 5 is visible from the outside. .

  Various types of filters 5 can be used. In this embodiment, a so-called membrane filter having a planar shape (film shape) such as cellulose acetate or polyethylene is used.

  Moreover, the filter pore diameter of this filter 5 should just be able to catch the turbidity by a membrane breakage, and since it is better that a pressure loss is small, it makes it larger than the filter pore diameter of the filter membrane in the filtration apparatus 1. FIG. For example, when the filtration device 1 performs raw water filtration in a sludge treatment plant as in this embodiment, the filtration pore diameter of the filtration membrane of this filtration device 1 is usually about 0.1 μm to 0.4 μm. On the other hand, the filter 5 has a pore size of 1 μm or more, preferably 1 μm to 20 μm. Note that the filter 5 itself is preferably a color in which dirt such as white is conspicuous.

  Further, in this embodiment, such a filter 5 is housed in a flow path (branch pipe 6) of filtered water T by being partly or entirely housed in a transparent resin housing 10 or the like. It is in a state visible from the outside, that is, a state in which dirt or the like of the filter 5 can be visually confirmed through the housing 10 from the outside of the housing 10. Here, the housing 10 is, for example, in the shape of a disk having a hollow inside, and both the connection portions 7 and 8 side of the branch pipe 6 are connected to the center portions of both surfaces perpendicularly to each other, so that the cross section in the housing 10 It communicates with a circular hollow part. The planar filter 5 has a circular shape that can be accommodated in the hollow portion, and is supported so as to be substantially parallel to the both surfaces and to extend over the entire surface of the hollow portion in a direction parallel to the both surfaces. ing. Therefore, the planar filter 5 is disposed so that the planar portion thereof is opposed to the flow direction F of the filtered water T flowing through the branch pipe 6.

  The shape of the filter 5 is not limited as long as it is in the housing 10 that can be observed from the outside. It may be a flat rectangular shape, a hollow fiber membrane with external pressure, or a tubular membrane with external pressure. The material may also be ceramic or metal.

  Furthermore, in this embodiment, the branch pipe 6 is connected to the collective drain pipe 4 as described above to form a flow path for the filtered water T, and the filter 5 visible from the outside is provided in the branch pipe 6. Even when a large amount of filtered water T is discharged as in the filtering device 1 in FIG. That is, it is difficult to directly place the filter 5 in the collective drain pipe 4 or the drain pipe 3 because the pressure loss in the pipe becomes too high. Thus, by providing the branch pipe 6 and installing the filter 5 as in the present embodiment, only the amount of filtered water T necessary for detection is guided to the branch pipe 6, causing the above-described difficulties. Without fail, reliable detection can be performed.

  Further, in this embodiment, when the branch pipe 6 is connected to the collective drain pipe 4 to form the flow path of the filtrate water T, the connection of the branch pipe 6 with the collective drain pipe 4 is faced. A throttle 9 is provided in the collective drainage pipe 4 on the downstream side in the flow direction F of the section 7, and thereby the connection on the downstream side in the flow direction F opposite to the connection portion 7 on the upstream side in the flow direction F of the filtrate T. An in-tube differential pressure is generated between the portion 8 and the portion 8. For this reason, according to this embodiment, the filtrate water T can be always introduced from the collective drainage pipe 4 to the branch pipe 6 and flow without causing the filtrate water T to stay in the branch pipe 6. It is possible to detect filtration membrane breakage by passing the filtered water T through the filter 5.

  In this embodiment, the throttle 9 is provided in the collective drainage pipe 4 so as to face the connecting portion 7 on the upstream side in the flow direction F as described above. For example, as shown in FIG. An annular venturi 11 having a convex curved section and projecting toward the inner peripheral side is provided so as to face the downstream connecting portion 8 and the inner diameter of the collective drainage pipe 4 is reduced. In the connecting portion 8 on the downstream side in the direction F, an opening may be made at the protruding end of the venturi 11 protruding to the inner peripheral side of the collective drainage pipe 4. Even in such a case, the filtered water T can always be introduced from the collecting drainage pipe 4 into the branch pipe 6 by the venturi effect, so that it is possible to reliably detect the filtration membrane breakage.

  In the filtration membrane breakage detection device in the filtration device 1 configured as described above, if any one of the plurality of filtration modules 2 is damaged during the filtration operation by the filtration device 1, the filtration membrane is trapped by the filtration membrane. The raw water still containing turbidity to be filtered leaks out from the damaged portion and mixes with the filtered water T, and the flow of the filtered water T connected to the filtration module 2 along the flow direction F of the filtered water T. It flows into the collective drainage pipe 4 from the drainage pipe 3 as a road. And in the part provided with the said detection apparatus of this collective drainage pipe 4, filtered water T flows in into the branch pipe 6 used as the flow path of filtered water T, passes through the filter 5, and at this time filtered water T and Turbidity in the mixed raw water is captured and gradually deposited on the filter 5.

  Therefore, according to the filtration membrane breakage detection apparatus having the above-described configuration, the breakage is small and the raw water leaking from the filtration membrane is also small. Even in this case, while the filtered water T mixed with the raw water passes through the filter 5, the filter 5 gradually becomes dirty due to the accumulation of turbidity in the raw water. Since it is visible, it can be easily confirmed without observing it visually, and it is possible to reliably detect breakage of the filtration membrane in the filtration device 1. Then, the contamination of the filter 5 due to the accumulation of the turbidity is caused by the filtered water T flowing through the flow path and being discharged during the filtration operation in the filtration device 1. The filter membrane is not detected for the first time at any time, and therefore the filtration membrane is not damaged and the filtration is not continued for a long time. This can be detected.

  In addition, the detection device having only such a filter 5 itself has a measuring device such as a turbidimeter and a particle counter as described above, and a gas supply means is provided in the membrane module 2 itself. Even if the branch pipe 6 is connected to the collective drain pipe 4 and the filter 5 is interposed therein as in this embodiment, it can be installed at a much lower cost. For this reason, in the present embodiment, the detection device is provided in the collective drainage pipe 4 as the flow path of the filtered water T in this way. For example, each of the individual drainage pipes 3 connected to the plurality of membrane modules 2 It is also possible to provide such a detection device, so that even if there are a large number of membrane modules 2, it is possible to quickly detect which one of the membrane modules is damaged, although it is inexpensive. .

It is the schematic which shows one Embodiment of this invention. It is an enlarged view of the broken-line A part in FIG. It is a figure equivalent to the enlarged view of the broken-line A part in FIG. 1, which shows the modification of embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Membrane module 3 Drain pipe 4 Collecting drain pipe 5 Filter 6 Branch pipe 7,8 Connection part of the collective drain pipe 4 and the branch pipe 6 9 Restriction 10 Housing 11 Venturi T Filtered water F Flow direction of filtered water T

Claims (5)

A filtration membrane breakage detection device, wherein a filter visible from the outside is provided in a flow path of filtrate water filtered from the raw water in a filtration device for filtering raw water with a filtration membrane. The drain pipe of the filtered water discharged from the filtration device is provided with a branch pipe having a smaller cross section than the drain pipe as a flow path of the filtrate water, and is branched from the drain pipe. 2. The filtration membrane breakage detection device according to claim 1, wherein the filter is disposed. The filtration membrane breakage detection device according to claim 2, wherein the drainage pipe is provided with a throttle or a venturi facing a connection portion with the branch pipe. The filter has a planar shape facing the flow direction of the filtered water in the flow path, and is housed in a housing in which all or part of the filter is transparent and can observe the filter, and is interposed in the flow path of the filtered water. The filtration membrane breakage detection device according to any one of claims 1 to 3, wherein the filtration membrane breakage detection device is provided. The filtration membrane breakage detection device according to any one of claims 1 to 4, wherein a filtration pore diameter of the filter is in a range of 1 µm to 20 µm.

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