JPS62250908A - Hollow yarn type filter - Google Patents

Abstract

PURPOSE:To reduce fluidization resistance of the inside of hollow yarn without reducing the membrane area of hollow yarn and to enhance air washability by providing a catchment chamber of filtrate to the lower end part of a hollow yarn filter having apertures in both ends and uniformly dispersing large hollow yarn in a bundle of hollow yarn in the specified proportion. CONSTITUTION:Large hollow yarn 11 having inner diameter of 1-5mm is uniformly dispersed and mixed in ordinary hollow yarn 10 in the range of 1-30% for the number of all hollow yarns and fixed to the inside of an outer cylinder 16 by upper and lower adhesives 4 in such a state that both ends are opened and a catchment chamber 5 of filtrate is closely sealed by an O-ring 9 and provided to the lower end part of a filter. A skirt-shaped recessed part 6 for air collection is closely sealed in the outer cylinder 16 and provided around the catchment chamber 5. The large hollow yarn 11 acts as the filter of liquid to be treated and simultaneously as a catchment pipe. In case of backwashing or air scrubbing, the air fed through an air introduction nozzle of the lower part of the filter is assembled in the recessed part 6 and introduced into the filter through a slit 7 and air introduction ports 8 and hollow yarn is vibrated thereby and metallic colloid stuck to hollow yarn is shaken off.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior Art) The present invention provides a method for removing colloidal substances etc. in a solution.
This invention relates to a suspended hollow fiber filter that uses external pressure.

(Prior art and its problems) Hollow fiber filters are economical because they have a large membrane area per unit volume, and are used in various fields such as semiconductors, medicine, and food. By reducing the diameter of the hollow fibers, it is possible to increase the number of membranes packed per unit volume, but there is resistance to water flowing through the hollow fibers, so hollow fiber filters with a length of about 1 inch are usually used. There is. However, recently, in nuclear power plants and the like, there is a tendency to increase the length of hollow fiber filters in order to minimize the installation area. The filter used in nuclear power plants is a suspended type filter with external pressure total filtration.
The lower end of the filter is closed and the filtrate is drawn out to the -L end of the filter. Therefore, i+! When the length of the filter becomes longer, the amount of filtrate hardly increases even if the length of the filter is increased due to the resistance of water flowing through the hollow fibers. JP-A No. 60-206415, 'I! r Kaisho 60-2443
In order to solve these drawbacks, No. 05 has one water intake pipe in the center of the filter, a pneumatic feed pipe running parallel to it, and a large number of hollow fibers surrounding the water intake pipe and the pneumatic feed pipe. (Japanese Unexamined Patent Publication No. 60-206415), or by using two or more filtration member units in which hollow fiber bundles are fixed in a U-shape to the inner surface of a nap member, a U-shaped hollow fiber bundle can be obtained. They are arranged to face each other, and one filtrate pipe is arranged in the center or four filtrate pipes are arranged in the four corners (Japanese Patent Application Laid-Open No. 60-244305), and the I! ! Excess water is removed.

However, in this type of system, the number of hollow pipes is extremely small (one or several), and their placement position is limited, for example, only in the center, so the filtration performance of the hollow fiber membrane is good. In this case, it is necessary to increase the diameter of the hollow pipe for extracting the discharged water, which inevitably reduces the number of hollow fibers that can be filled in the filter, resulting in a decrease in filtration capacity. Furthermore, in order to remove attached metal colloid, etc., such a filter periodically performs air backwashing or air scrubbing, vibrates the hollow fibers, and discharges metal colloid, etc. from the system. When the number of filled hollow fibers is increased, the vibration of the hollow fibers decreases even when air backwashing or air scrubbing is performed, and the removal performance of attached metal colloids etc. decreases, and the removal of attached metal colloids etc. There were problems such as metal colloids being caught between the hollow fibers and difficult to extract from the system.

(Object of the Invention) In order to solve the above-mentioned problems, an object of the present invention is to reduce the flow resistance in the hollow fiber without reducing the membrane area of the hollow fiber, and to provide a hollow fiber type Il with good air cleaning performance. ! It is to provide over-the-counter equipment.

(Structure of the Invention) The hollow fiber filter of the present invention is a hollow fiber type filter that is used in a suspended state, with openings at both upper and lower ends of the filter, and a filtrate at the lower end of the filter. A water collection chamber is provided, and hollow fibers having an inner diameter of 1 to 5 mm are uniformly dispersed and mixed in the hollow fiber bundle in a range of 1 to 30% of the total number of hollow fibers.

(Embodiments and Effects) The present invention will be described below with reference to an embodiment shown in the drawings, but the present invention is not limited to this scope.The filter of the present invention, as shown in FIG. A large number of hollow fibers 10.11 with both ends open are fixed in the outer cylinder 16 by upper and lower adhesives 4, and a water collection chamber 5 for the filtrate is formed at the lower end of the filter by an O-ring 9. It is sealed and set up.

Around the water collection chamber 5, a skirt-shaped recess 6 is provided with an O-ring 9.
It is provided in the outer cylinder 16 in a sealed manner. The recess 6 is open in a skirt shape and has a shape that easily collects air. The collected air enters the filter 3 through the slit 7 and the air inlet 8.

Hollow fibers used in known filters usually have an inner diameter of 0.1~0.
8mm, with an outer diameter of about 0.3 to 1.5mm,
In the present invention, as shown in FIG. 2, thick hollow fibers 11 having an inner diameter of 1 to 5 mm are uniformly dispersed and mixed into the ordinary hollow fibers 10 in a range of 1 to 30% of the total number of hollow fibers. ing. This thick hollow fiber acts as a water collecting pipe while filtering the liquid to be treated.The thick hollow fiber with an inner diameter of 1 to 5 mm mixed in with the normal hollow fiber may be made of the same material as the normal hollow fiber. Even if thin hollow fibers are made thicker in a similar manner, the compressive strength will decrease slightly when used under external pressure.Moreover, hollow fibers related to nuclear power are generally used as microfilters with pore diameters of about 0.05 to 0.3 gm. is used, and the amount of filtrated water decreases in proportion to the membrane thickness, so increasing the inner diameter will lower the flow resistance, but the compressive strength and amount of filtrated water will decrease, so the inner diameter of the hollow fibers to be mixed should be 1 to 5 mm. is preferred. Further, the mixing ratio is preferably 1 to 30%, and if it is less than 1%, the water collection effect is small, and if it exceeds 30%, the membrane area will decrease and the amount of filtrated water will decrease, which is not preferred.

FIG. 3 shows how the hollow fiber filter of the present invention is used. The filter 3 is suspended from a partition plate 2 inside the pressure vessel 1. The pressure vessel has an inlet pipe 12 for the liquid to be treated and an outlet pipe 13 for the filtrate.
, an outlet 14 for discharging metal colloids etc. attached to the hollow fibers, and nozzles 15 and 18 for introducing air into the filter. Is the liquid to be treated outside the filter? , 'il 6 enters the filter through the hole 17, is filtered from the outside of the hollow fibers 10 and 11, and flows inside the hollow fiber. The cancer water flowing to the lower end of the filter collects in the water collection chamber 5 at the lower end of the filter, and then
It passes through the hollow fiber 11 of mm and is sent above the partition plate 2,
Together with the water flowing to the upper end, the filtrate is extracted from the system through the filtrate extraction pipe 13.

When the filtration differential pressure of the hollow fiber filter exceeds a certain pressure, i!
! The flow is stopped and backwashing or air scrubbing is performed. That is, backwashing is performed in which air is introduced from an air introduction nozzle 18 provided in the filtrate extraction pipe 13 to push out water accumulated on the upper part of the partition plate 2 in the pressure vessel 1, or Air is introduced through the air introduction nozzle 15, collected in the skirt-like air collection recess 6 provided at the bottom of the filter, and passed through the slit 7 and the air introduction hole 8 along the hollow fibers 10.11. Air scrubbing is performed by vibrating the hollow fibers while raising the hollow fibers. Metal colloids, etc. that have fallen off from the hollow fibers are taken out from the hole 17 at the bottom of the outer cylinder of the hollow fiber filter or the air introduction hole 8 and placed in a pressure vessel. It is extracted from the system through an exhaust roller 14 provided at the bottom of the system. The filter whose capacity has been restored by cleaning can be used again.

Next, test results using the filter of the present invention will be shown in comparison with a comparative example.

(Example) A 2100 mm long PP" pipe (inner diameter 123.4 mm, outer diameter 140.0 mm) was used as the module outer cylinder, and polyolefin hollow fibers (inner diameter 0.68 mm, outer diameter 1.20 mm) and fluorine-based hollow fibers (inner diameter 2 mm, outer diameter 3 mm) are adhesively fixed at both the upper and lower ends with epoxy resin and evenly distributed and filled. A water collection chamber is provided at the lower end of the outer cylinder and the filter is assembled. It was created.

At that time, the number of polyolefin hollow fibers and fluorine-based hollow fibers to be used, the number of fluorine-based hollow fibers used, The mixing ratio of the fibers to the total hollow fibers was varied to uniformly disperse and fill the fibers. This filter is of the suspended type shown in FIG.
It was used in an external pressure total filtration of kg/ctn', and the cancer filtrate collected at the upper end of the filter was measured. In addition, air was introduced from the air inlet (15) at the bottom of the filter at a pressure of 1 kg/ctn'', and the vibration state of the hollow fibers was observed. The results of 0 or more are summarized in Table 1.

(Left below) (Comparative example) The same PP vibrator as in the example was used as the module outer cylinder, and a PP vibrator (inner diameter 40 mm, outer diameter 48 mm) was placed in the center of the module.
mm), and the filling rate is 54 around this inserted pipe.
．． A known type of filter was prepared by filling the same polyolefin hollow fibers as in the example to a concentration of 8% and having openings at both ends and a water collection chamber at the lower end.

Using this filter, the amount of filtered water and the vibration of the yarn due to air scraping were observed under the same conditions as in the example. The results are summarized in Table 2.

(Effects of the Invention) According to the present invention, hollow fiber membranes can be filled with almost no reduction in membrane area per unit volume, and thin hollow fibers and thick hollow fibers are uniformly dispersed and mixed in the hollow fiber bundle. Because
During air backwashing or air scrubbing, the air sufficiently enters into the yarn bundle, the vibration of the yarn becomes uniform, and the shaken-off metal colloid is easily removed, making it possible to provide a hollow fiber filter with good cleaning recovery properties. .

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic sectional view of a filter, Fig. 2 is an explanatory diagram showing the state of dispersion of hollow fibers,
FIG. 3 is an explanatory diagram showing how the filter is used. 1. Pressure vessel 10. Thin hollow fiber 2, partition plate
11. Thick hollow fiber 3, hollow fiber filter 12. Processed liquid introduction pipe 4, adhesive 13. Filtrate extraction pipe 5, water collection chamber 14. metal colloid outlet 6;
Air gathering recess 15. Air introduction nozzle 7, slit 16. Outer cylinder 8, air introduction hole 17. hole

Claims (2)

[Claims] (1) In a hollow fiber filter that is used in a suspended state, both the upper and lower ends of the filter are opened, and a water collection chamber for the filtrate is provided at the lower end of the filter, and the hollow fiber bundle is has an inner diameter of 1 to 5
1. A hollow fiber type filter characterized in that hollow fibers having a diameter of 1 mm are uniformly dispersed and mixed in the range of 1 to 30% of the total number of hollow fibers. (2) A hollow fiber filter according to claim 1, wherein a skirt-like air collection recess is provided at the lower end of the filter.