JPH0729031B2 - Hollow fiber type ultra filter module - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hollow fiber type ultrapermeation membrane module used as a point-of-use filter for ultrapure water used in the electronics industry and the like.

(Prior Art) 256K bits are the mainstream of VLSIs today, but 1M bits have already started to be shipped. In these VLSI manufacturing processes, ultrapure water is used to clean semi-finished VLSI products.
There is a close relationship between the quality of ultrapure water and the yield of products. Therefore, recently, the quality of ultrapure water has dramatically improved.

An example of a recent ultrapure water production system is shown in FIG.

After removing most of the suspended solids from the raw water by the coagulation filter 2,
The reverse osmosis membrane 3 removes most of suspended matter, dissolved organic matter (TOC), dissolved inorganic matter, and ionic substances. Furthermore, after removing the remaining ionic substances with the ion exchanger 4, the ultraviolet germicidal lamp 5
The bacteria that are alive are sterilized, the ionic substances are completely removed by the high-performance ion exchanger 6, and dead bodies and fine particles of the bacteria from the upstream are removed by the ultrapermeabilization membrane 7. The water that has passed through the ultrapermeable membrane is once again circulated to the ultraviolet germicidal lamp 5 except for being used, and measures are taken to prevent the accumulation of dirt.

The quality of this ultrapure water is 20 to 30 ° C, specific resistance 18 MΩ · cm or more, TOC 50 ppb or less, viable cell count 0.1 / ml or less, particle size 0.1 μm.
It is about 50 particles / ml or more and m or less.

Recently, however, the demand for ultrapure water has become even more stringent as LSIs proceed to 1Mbit and 4Mbit. Although the official standard has not been established yet, for example, specific resistance of 18 MΩcm or more, TOC of 10 ppb or less, viable cell count of 0.001 cells / ml or less, particle size of 0.05
It is 50 particles / ml or less of μm or more.

(Problems to be Solved by the Invention) There are some problems in producing such ultrapure water. In FIG. 1, the water discharged from the ultrafiltration membrane module 7 becomes a loop pipe and circulates in the LSI manufacturing site, but this pipe is very long and has several use points. Therefore, even if the water that has flowed out of the ultrafiltration membrane has a high purity, the purity gradually decreases due to the pollution from the piping and the reverse pollution from the point of use. The most contaminated of these are fine particles and live bacteria.

In such a large central type ultrapure water device, it is difficult to sterilize the whole system even if it is found that it is contaminated with live bacteria. This is because it is not permissible to stop the supply of ultrapure water, and there are some dead ends in the long piping system, and the bactericide does not sufficiently enter. Further, in a long piping system, there is much contamination of fine particles.

Due to this kind of problem, some use point filters have been released recently. It is for the purpose of removing fine particles and live bacteria from the ultrapure water line by inserting a small filter 8 just before use as shown in FIG. This filter is classified into an ultra-peripheral membrane type and a precision peri-membrane type, but if the particles to be removed are as small as 0.05 μm in size, only the ultra-peritoneal membrane can be used.

Since the condition of this use point filter 8 is the use point, water is often used or stopped, so that high purity water is required from the beginning of use.

In other words, there is a strong demand for quick restoration of raw water. However, current use point filters do not have this condition.

In addition to the small number of ultrapure membrane use-point filters, the structure inside the filter is poor and water accumulates, resulting in slow recovery of raw water.

Therefore, as a result of intensive studies, the present inventors have completed the present invention.

(Means for Solving Problems) That is, according to the present invention, "raw water inlet is provided beside the housing, permeate outlet is provided on the housing, and the raw water retention portion is filled with an adhesive to retain the raw water. It is a hollow fiber ultrafiltration membrane module with less.

The present invention will be described below with reference to FIG.

In FIG. 3, 11 is a raw water inlet nozzle, 12 is a permeate water nozzle, 13 is a cylindrical case, 14 is a cap, 15 is an air bleeding plug, 16 is a cylindrical net for protecting hollow fibers, and 17 is a hollow. Thread, 18 is a filling adhesive to eliminate the stagnant part of raw water,
19 is an adhesive that seals one side of the hollow fibers, 20 is an adhesive that bonds the hollow fibers to each other and to the case, and 21 is a case 13
This is an O-ring for sealing between the cap and the cap 14.

According to the present invention, raw water enters from the direction shown by the arrow in FIG. 3 and flows from the outside to the inside of the hollow fiber while flowing through the surrounding clearance in the case. Water permeates the walls of the hollow fibers due to the pressure difference between the outer surface and the inner surface of the hollow fibers, enters the inside of each hollow fiber, flows upward, and exits from the permeated water nozzle 12. When flowing in this way, if the 18 parts are not filled with adhesive, it will stay in a place where water does not flow, but the present invention does not have such a staying part at all, and water entering from the inlet stays There is almost no, and you will be taken to the exit.

(Effects of the Invention) The hollow fiber type ultrapermeation membrane module for ultrapure water use point filters according to the present invention accumulates in the module when water intake is stopped because the liquid retention portion in the module is filled with an adhesive. The amount of water with reduced purity is small, and the recovery of raw water at the start of water intake, that is, the resistivity and TOC return to normal quickly.

(Examples) Next, the present invention will be described more specifically by way of examples.

Example 1 In FIG. 3, made of polyether sulfone, molecular weight cutoff of 50,000, inner diameter 400 μm, outer diameter 600 μm, number 6000, effective length
An ultrapermeabilizer module was made using 22 cm hollow fiber. In addition, the hollow fiber has a water permeability of 8 /
It was minutes, m ^2, and atmospheric pressure.

This module was connected to an ultrapure water line with a specific resistance of 18 MΩ · cm and TOC 50 ppb, and 500 / h of ultrapure water was passed through at 25 ° C. Then, measure the specific resistance and TOC of water coming out from the permeate side of the module from the start, and the specific resistance is 17.9 MΩ ・
The time over cm and the time when TOC became 60 ppb or less were measured. The results of the experiment are shown in Table 1.

Comparative Example 1 For comparison, 18 modules in FIG. 3 which were not bonded were prepared and the same experiment as in Example 1 was carried out. The results are shown in Table 1.

As described above, it can be seen that the time required for Example 1 to be usable is half to one-third as compared with Comparative Example 1.

[Brief description of drawings]

FIG. 1 is an example of a recent ultrapure water production system, and FIG. 2 is an example in which a point-of-use filter 8 is added to FIG.
FIG. 3 shows an example of a hollow fiber type ultrapermeation membrane module according to the present invention. 1 ... Raw water tank, 2 ... Coagulator, 3 ... Reverse osmosis membrane, 4
...... Ion exchanger, 5 ... UV germicidal lamp, 6 ... High-performance ion exchanger, 7 ... Ultrafiltration membrane, 8 ... Use point filter, 11 ... Raw water inlet nozzle, 12 ... Permeate water nozzle , 13 …… Cylindrical case, 14 …… Cap, 15 …… Air vent plug, 16 …… Cylindrical net, 17 …… Hollow fiber, 1
8,19,20 …… Adhesive, 21 …… O-ring

Claims (1)

[Claims] 1. A hollow fiber ultrafiltration membrane module having a raw water inlet beside the housing and a permeate outlet above the housing, and the raw water retention portion is filled with an adhesive to reduce the retention of the raw water. .