JPS645926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hollow fiber membrane filtration device for filtering fine suspended substances contained in a liquid.

[Prior art]

A hollow fiber membrane filtration device divides the inside of a tank into a filtration chamber and a filtrate chamber with a partition plate, supports a plurality of hollow fiber membranes with one end open in the filtrate chamber, and For example, as shown in FIG. 12, one end of a plurality of hollow fiber membranes 1 is passed through a focusing plate 2 and bundled, and the other end is closed with an adhesive or the like. is closed to form a free focusing body, and this focusing plate 2 is attached to a partition plate 3 in the tank with a holding plate 4,
The hollow fiber membranes 1 are attached via bolts 5, O-rings 6, etc., and one end of these hollow fiber membranes 1 is opened to the filtrate chamber 7, and supported in the filtration chamber 8, and is further fixed to the partition plate 3 for liquid permeability protection. The one housed in the outer cylinder 9 is used.

[Problem that the invention seeks to solve]

In this type of hollow fiber membrane filtration device, it is desirable to minimize the installation area, so attempts have been made to increase the length of the hollow fiber membrane unit.

However, as shown in FIG. 13, the hollow fiber membrane 1 has a permeated liquid amount Q
Although the values are different, when the length exceeds a certain value, the amount of permeated liquid Q becomes almost constant for a certain constant pressure of the stock solution supplied, and there is a limit to the effective length of the hollow fiber membrane 1. It turned out that there was no point in making it too long.

As described above, since there is a limit to the effective length of the hollow fiber membrane, if the length of the hollow fiber membrane is longer than that, the entire length will not work effectively, and an unnecessary depth of the tank will be required.
For example, when using a hollow fiber membrane with an inner diameter of 0.4 to 0.5 mm and a total length of 1200 mm, the effective area is about 600 mm in the upper half.
The lower half could not be expected to have a liquid permeability of 600mm, and the tank needed to be unnecessarily deep.

The present invention utilizes the liquid permeability characteristics of the hollow fiber membrane, and effectively utilizes the entire length of the hollow fiber membrane to reduce the tank depth, or increase the filtration capacity with the same tank depth. Another object of the present invention is to provide a hollow fiber membrane filtration device in which the filtration capacity can be increased by increasing the length of the hollow fiber membrane unit, and the installation floor area can be reduced.

[Means and actions for solving problems]

In the present invention, the inside of the tank is divided into a filtration chamber and a filtrate chamber by a partition plate, a plurality of hollow fiber membranes having one end opened in the filtrate chamber are supported in the filtration chamber, and the other hollow fiber membranes are The plurality of hollow fibers are characterized in that an airtight liquid collection chamber is provided at one end and the other end communicates with the other end, and the airtight liquid collection chamber and the filtration chamber are communicated through a communication tube. It is also characterized in that the plurality of hollow fiber membranes and the communicating tubes are partitioned into a plurality of sets in the longitudinal direction by interposing one or more intermediate sealed liquid collection chambers which are opened in the middle of the membranes and the communicating tubes. This is a hollow fiber membrane filtration device.

That is, during filtration, pressurized water is passed from the outside to the inside of the hollow fiber membrane, and during backwashing, pressurized water is passed in the opposite direction from the inside to the outside. This is a hollow fiber membrane filtration device that performs air scrubbing in which these hollow fiber membranes are hydraulically agitated by blowing air in and shaking water. The filtered filtrate flows upward, and the filtrate filtered almost in the lower half flows to the lower half.
The communicating pipe is used as an outlet pipe for the filtrate in the substantially lower half and an inlet pipe for pressurized water for backwashing the hollow fiber membrane in the substantially lower half, and the hollow fiber membranes and the communicating pipe are arranged in multiple stages in the longitudinal direction. This allows the length to be increased by overlapping. Therefore, by reducing the flow path resistance in the longitudinal direction within the hollow fiber membrane due to the narrow inner diameter of the hollow fiber membrane, the cake layer of suspended matter can be reduced within the filtration differential pressure allowable for the filtration device. Increasing the ratio of net filtration differential pressure caused by
As the length of the hollow fiber membrane increases, the average filtration capacity per unit length of the hollow fiber membrane is prevented from decreasing, and the effective utilization rate in the length direction of the hollow fiber membrane is improved. Also, it is possible to increase the length of the communicating pipe in the longitudinal direction.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, in FIGS. 1 and 2a, one end of a plurality of hollow fiber membranes 1 is passed through a focusing plate 2 and fixed together with a protective outer cylinder 9, and this focusing plate 2 is secured with a holding plate 4, bolts 5, etc. It is attached to the partition plate 3 and supports the plurality of hollow fiber membranes 1 in the filtration chamber 8 so that one end thereof opens into the filtrate chamber 7 . Further, the other end of the hollow fiber membrane 1 in the filtration chamber 8 also penetrates the focusing plate 2 and is fixed together with the other end of the protective outer cylinder 9, and the lid 10 is connected to the end of each hollow fiber membrane 1. A hermetically sealed liquid collection chamber 11 is provided in communication with the filtrate chamber 7, and this hermetic liquid collection chamber 11 and the filtrate chamber 7 are communicated through a communication pipe 12.

The communicating tube 12 may have a diameter having a resistance smaller than the total liquid flow resistance of the hollow fiber membrane 1, and both ends thereof may be fixed with focusing plates 2, 2.
As shown in FIGS. 3 and 4a, a reinforcing tube 13 is arranged around a plurality of bundled hollow fiber membranes 1 and, if necessary, both ends are fixed to the bundle plates 2, 2. The central part of the hollow fiber membrane 1 is penetrated and reinforced. In this way, when the communication pipe 12 is arranged around the bundled hollow fiber membrane 1, the protective outer cylinder 9 can be omitted.

Note that in this case, it is necessary to increase the diameter and number of the communicating tubes 12 so that the communicating tubes 12 have a resistance smaller than the total backflow resistance of the hollow fiber membranes 1.

In the figure, 14 indicates an air distribution plate provided at the lower part of the filtration chamber 8.

A schematic diagram of the entire filtration apparatus is shown in FIG.

The stock solution to be filtered is then pressurized into the filtration chamber 8, passes through the protective outer cylinder 9 (FIG. 1) or the gap between the communication tubes 12 (FIG. 3), and reaches each hollow fiber membrane 1.
It is filtered from the outside to the inside of each hollow fiber membrane 1. The filtrate that has been filtered and entered inside each hollow fiber membrane 1 is divided into upper and lower parts from approximately the center of the length of each hollow fiber membrane 1, with one directly entering the filtrate chamber 7 and the other flowing into a closed liquid collection chamber. 11
The liquid is collected into the filtrate chamber 7 via the communication pipe 12, and taken out of the tank.

In this way, the filtrate filtered by each hollow fiber membrane 1 is divided into upper and lower parts within each hollow fiber membrane 1 and taken out, so if the total length of the hollow fiber membrane 1 is longer than the effective length limit described above, But you can use this to your advantage.

Furthermore, as such filtration continues, suspended matter in the liquid is captured on the surface of the hollow fiber membrane 1 and the resistance to liquid passage increases, so filtration is stopped after a certain period of time and backwashing is performed. There must be. In backwashing, contrary to the case of filtration, when pressurized water for backwashing is injected into the filtrate chamber 7, the pressurized water flows from the filtrate chamber 7 side of each hollow fiber membrane 1.
Pressurized water flows from the other end of each hollow fiber membrane 1 through the communication pipe 12 and the sealed liquid collection chamber 11, and flows back from the inside to the outside of each hollow fiber membrane 1 to make it easier to peel off deposits,
Thereafter, a scrubbing operation using air is performed to promote the removal of suspended matter adhering to the surface of the hollow fiber membrane 1. That is, air scrubbing involves blowing air from the air dispersion plate 14 into the water, and when the protective outer cylinder 9 or the communication pipe 12 is located on the outer periphery, the flow of air bubbles passing through the gap causes intense damage to each hollow fiber membrane 1. Vibration is applied to peel off the deposits, but during this time both ends of each hollow fiber membrane 1 are fixed, so there is no entanglement and there is little chance of breakage.

In addition, when the diameter of the bundled part of the hollow fiber membrane 1 increases, the solid content attached to the hollow fiber membrane 1 in the center becomes difficult to flow out to the outside of the bundled part even if it is backwashed with pressurized water and pushed out. Washing efficiency decreases. In order to prevent this, a central gap 19 with a width of 2 to 10 mm is provided between the central communicating tube 12 or reinforcing tube 13 and the convergence part of the hollow fiber membrane 1 (Fig. 2b, Fig. 4b). ,
In addition, a plurality of radial gaps 20 with a width of 3 to 10 mm may be provided in the radial direction of the cross section of the convergence section, so that solids separated from the hollow fiber membrane 1 during backwashing can easily flow out to the outermost side. , preferred for improving backwashing efficiency.

Furthermore, when rinsing the hollow fiber membrane 1 by air scrubbing, a swinging space is secured,
In addition, in order to swing appropriately, a peripheral gap 21 with a width of 3 to 10 mm is provided between the focusing part and the mesh-like protective outer cylinder 9.
It is also preferable to provide. In the illustrated examples of FIGS. 3, 4a, and 4b, the outer circumferential gap 21 is not provided between the surrounding communication tube 12 and the hollow fiber membrane 1, but it is also possible to provide one.

Although it is not necessarily necessary when the diameter of the converging portion of the hollow fiber membrane 1 is small, when the diameter is large, an air outlet 15 may be provided as shown in FIGS. 6, 7a, and 7b. The air pipe 16 is passed through the center of the plurality of hollow fiber membranes 1, the upper end is closed, the lower end is opened under the air distribution plate 14, and the air outlet 15 is guided into the surrounding hollow fiber membrane 1. Accordingly, air can also be blown out from the inner hollow fiber membrane 1 to further promote detachment of deposits. It is preferable that the air outlet 15 is also opened near the focusing plate 2 so as to remove suspended matter deposited on the focusing plate 2.

Note that instead of passing the air pipe 16 through the inside of the communication pipe 12, the communication pipe 12 can also be provided inside the air pipe 16.

In addition, in the illustrated examples of FIGS. 3 and 4a,
The reinforcing tube 13 can be used as an air tube to provide an air outlet.

Next, other embodiments of the present invention will be described.

In FIGS. 8 and 9a, most of the embodiments are the same as those shown in FIGS. 1 and 2a, but the length of the hollow fiber membrane 1 is made longer than twice its effective length. For convenience when necessary or when the installation work space is narrow, an intermediate sealed liquid collection chamber 18 is interposed between the hollow fiber membrane 1 and the communicating tube 12, the ends of which are open. That is, each hollow fiber membrane 1 and the communicating tube 12 are divided in the middle, the ends of the hollow fiber membrane 1 and the communicating tube 12 at each divided portion are respectively penetrated and fixed to the focusing plates 2, 2, and these are connected into a connecting ring. The hollow fiber membranes 1 and the communication tubes 12 are connected in the longitudinal direction, and an intermediate sealed liquid collecting chamber 18 is provided at the connecting portion to connect the hollow fiber membranes 1 and the communication tubes 12 in the longitudinal direction. Depending on the required length of the thread membrane 1, a plurality of connections can be provided.

Therefore, the filtrate separated in each divided hollow fiber membrane 1 is collected in each intermediate sealed liquid collection chamber 18 and sealed liquid collection chamber 11, and is sequentially introduced to the filtrate chamber 7 through the communication pipe 12, respectively. If they can be connected in this way, installation and removal will be easier even if the work space is small, and even if a large number of them are connected to increase the filtration area, the projected installation area will not change.

In addition, the communicating tube 12 may be arranged around the convergence part of the hollow fiber membrane 1, and in that case, FIG. 10 and FIG.
It is as shown in the example shown in Fig. 1a, and the above-mentioned Fig. 3,
The configuration will be easily understood from the description of the illustrated example in FIGS. 4 and 4b.

In addition, if an air pipe is required for blowing out air from the center of the converging portion of the hollow fiber membrane 1 for air scrubbing, it is configured according to the embodiments shown in FIGS. 6 and 7a described above. However, it is also convenient to divide the air pipes so that they can be connected.

〔Effect of the invention〕

As described above, the present invention takes advantage of the liquid permeability characteristics of hollow fiber membranes, effectively utilizes the entire length of the hollow fiber membranes, and performs rational filtration, making it possible to reduce the depth of the tank or to maintain the same tank depth. The filtration capacity can be increased and the installation floor area can be reduced.Furthermore, by connecting such hollow fiber membrane units in a cassette type, the filtration capacity can be further increased without increasing the installation floor area. Moreover, even if the work space is small, the installation and removal work can be easily performed.

[Brief explanation of drawings]

1 to 11a show embodiments of the present invention, and the first
The figure is a sectional view showing one embodiment of the present invention, FIG. 2a is a sectional view taken along line A-A in FIG. 1, FIG. 2b is a cross-sectional view taken along line A-A showing another example, and FIG. FIG. 4a is a cross-sectional view taken along line BB in FIG. 3, FIG. 4b is a cross-sectional view taken along line B-B showing another example, and FIG. 5 is a cross-sectional view taken along line BB in FIG. Schematic diagram, FIG. 6 is a sectional view showing another embodiment of the present invention, FIG. 7a is a sectional view taken along the line C-C in FIG. 6, and FIG. , FIG. 8 is a sectional view showing another embodiment of the present invention, FIG. 9a is a sectional view taken along line DD in FIG. 8, and FIG. 9b is
10 is a sectional view showing another embodiment of the present invention, and FIG. 11a is a 10th sectional view showing another example.
The E-E sectional view in the figure, and FIG. 11b shows another example.
-E sectional view, FIG. 12 is a sectional view showing a part of a conventional hollow fiber membrane filtration device, and FIG. 13 is a diagram showing the relationship between the length of the hollow fiber membrane and the amount of permeated liquid. 1... Hollow fiber membrane, 2... Focusing plate, 3... Partition plate, 4... Holding plate, 5... Bolt, 6... O ring, 7... Filtrate chamber, 8... Filtration chamber, 9 ...Protective outer cylinder, 10... Lid body, 11... Sealed liquid collection chamber, 12...
... Communication pipe, 13 ... Reinforcement pipe, 14 ... Air distribution plate, 15 ... Air outlet, 16 ... Air pipe, 17
... Connecting ring, 18 ... Intermediate sealed liquid collection chamber, 19 ...
Center gap, 20...radial gap, 21...outer circumferential gap.

Claims (1)

[Scope of Claims] 1. The inside of the tank is divided into a filtration chamber and a filtrate chamber by a partition plate, and a plurality of hollow fiber membranes with one end opened in the filtrate chamber are supported in the filtration chamber, and the hollow fiber membranes are A hollow fiber membrane filtration device characterized in that a sealed liquid collection chamber is provided at the other end of the membrane and the other end communicates with the other end, and the sealed liquid collection chamber and the filtrate chamber are communicated with each other through a communication tube. . 2. The hollow fiber membrane filtration device according to claim 1, wherein a plurality of the communicating tubes are arranged around the plurality of hollow fiber membranes. 3 The inside of the tank is divided into a filtration chamber and a filtrate chamber by a partition plate, a plurality of hollow fiber membranes with one end open in the filtrate chamber are supported in the filtration chamber, and the other end of the hollow fiber membrane is A sealed liquid collection chamber is provided with the other end communicating with the other end, and the sealed liquid collection chamber and the filtration chamber are communicated through a communication pipe, which opens in the middle of the plurality of hollow fiber membranes and the communication pipe. 1. A hollow fiber membrane filtration device, characterized in that the plurality of hollow fiber membranes and communicating tubes are partitioned into a plurality of sets in the longitudinal direction by interposing one or more intermediate sealed liquid collection chambers. 4. The hollow fiber membrane filtration device according to claim 3, wherein a plurality of the communicating tubes are arranged around the plurality of hollow fiber membranes.