JPH0327254B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an external pressure filtration hollow fiber membrane module, and more particularly to an external pressure filtration hollow fiber membrane module in which the membrane element can be replaced with extremely little contamination on the filtrate side. It is something.

[Prior art]

Hollow fiber membrane modules have a high membrane packing density and can make filtration equipment smaller and lighter.
It is widely used in pure water production, food processing, and other fields, and has become indispensable as precision filtration filters, such as terminal filters in ultrapure water production used in semiconductor manufacturing.

Usually, a hollow fiber membrane module has a shape in which multiple hollow fibers are bundled together, both ends of which are fixedly sealed with a resin, etc., and then the resin-fixed part on at least one side is cut, and the end of the hollow fibers is opened. Common. In addition, the module is often used as an internal pressure filtration type in which the filtrate is press-fitted through the opening of the hollow fiber and the filtrate is taken out to the outside. This is because the flow of the filtration solution has the effect of washing away dirt on the membrane surface caused by filtration, and the module used is a hollow fiber with openings at both ends. On the other hand, when removing minute amounts of fine particles from an extremely clear filtration stock solution, an external pressure filtration type is also used in which the filtration stock solution is pressurized from the outside of the hollow fibers and the filtrate is taken out into the inside of the hollow fibers. However, with either type of module, it is difficult to completely eliminate fine particles in the filtrate, which poses a major problem when using this hollow fiber membrane module as a terminal filter in ultrapure water production, etc. Improvements are desired.

This fine particle is usually 0.2 μm or more or 0.1 μm
Although it is measured for objects larger than
Hollow fiber membrane modules for terminal filters in ultrapure water production use membranes that can block 100% of particles of this size, so it is unlikely that particles in the filtration stock solution are leaking through the membrane.
This is thought to be because fine particles are mixed into the filtrate from the part where the filtrate comes into contact with the hollow fiber membrane module.

The manufacturing process for hollow fiber membrane modules can be roughly divided into two steps: the process of making the membrane and the process of assembling the membrane into a module.In internal pressure filtration type modules, the outer surface of the hollow fiber membrane is on the filtrate side. Therefore, it is highly conceivable that the contamination of the membrane and the contamination of the inner surface of the housing body during the module assembly process directly affect the contamination of the filtrate, which is undesirable from a structural standpoint.

On the other hand, in external pressure filtration type modules, the inner surface of the hollow fiber membrane is on the filtrate side, so contamination of the membrane during the module assembly process and contamination of the inner surface of the housing body is less likely to directly affect the contamination of the filtrate. It can be said that it is superior to the upper internal pressure filtration type.

However, since the hollow fiber membrane is used by applying pressure from the outside, it is necessary to increase the pressure resistance of the housing that houses the membrane element, which causes the problem of high cost. For this reason, a type of module in which only the membrane element is replaceable has been proposed (Japanese Utility Model Publication No. 195301/1983).
Looking at the structure of the module, it consists of a housing, a cap, and a membrane element, and has a structure in which sealing members are used to provide liquid tightness between the housing and the membrane element, and between the cap and the membrane element. There are concerns about leakage from the sealing member and contamination of the filtrate contact surface when replacing the membrane element.

Furthermore, in the modular structure shown in Japanese Patent Application Laid-Open No. 61-234905, the opening side of the membrane element is adhesively fixed to the cap, and the structure takes into account contamination when replacing the membrane element. To fix the element to the housing, it is necessary to use a member that has two flow paths, one on the supply water side and one on the filtrate side, so the structure of the filtrate water flow path is complicated, and it is difficult to prevent communication between the supply water side and the filtrate side. Since this is done using a sealing member, the possibility of leakage cannot be denied.

[Objective of the Invention] The present invention was developed with the aim of obtaining a module with extremely low contamination on the filtrate side, which could not be achieved with conventional hollow fiber membrane modules.In addition to making the module type an external pressure filtration type, By integrating the membrane part and the cap body that forms the filtrate flow path, the shape of the filtrate flow path can be simplified, and it is possible to simultaneously reduce particulates in the filtrate and replace the membrane element. This knowledge led to the completion of the present invention.

[Structure of the invention]

The present invention provides a cap body in which one end of the hollow fiber membrane is fixed in a sealed state, the other end is fixed in a fixed state in an open state, and the fixed part on the other end side has a filtrate outlet and a flange. a hollow fiber membrane element fixed to both ends of a perforated cylindrical body with adhesively fixed parts and both fixed parts having rigidity, a flange supporting a cap body of the membrane element, and an inlet and an outlet for supply water. The present invention is an external pressure filtration type hollow fiber membrane module characterized by comprising a housing capable of accommodating at least a membrane portion of the membrane element.

What is important about the module of the present invention is that the membrane element is adhesively fixed to the cap body, the cap body has a flange, and the housing also has a flange, and the membrane element and the housing are connected at both flange parts. It can be easily attached and detached.

A more detailed explanation will be given below with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the hollow fiber membrane module of the present invention. The module of the present invention is
It basically consists of a membrane element 1 and a housing 2. The membrane element 1 consists of a cap 3 having a filtrate outlet 9 and a flange 10, a hollow fiber membrane 7, a perforated cylinder 6, and fixing parts 4, 5.
On the other hand, the housing 2 has a flange 11 that supports the cap body 3, and has an inlet 8 of supply water, which becomes the filtration stock solution, in the opposite direction to the flange 11. Further, a supply water outlet 13 is provided on the side wall of the housing 2 near the flange 11. The supply water outlet 13 is closed during filtration or the opening is narrowed to circulate a portion of the supply water, and is also used as an outlet for degassing the housing 2 and for cleaning water during cleaning.

The membrane element 1 and the housing 2 are connected to the flange 1 via a sealing member 12 such as an O-ring or a rubber sheet.
It has a structure in which it is fixed and integrated at points 0 and 11. The shapes of the flanges 10 and 11 are not particularly limited, as long as they can be sealed liquid-tight via the seal member 12. The cap 3 serves as a collection chamber for the filtrate, and has a filtrate outlet 9 on the opposite side of the fixed portion 4.
It is desirable that the inner surface of the cap that comes into contact with the filtrate be as smooth and simple as possible.

The fixed parts 4 and 5 are fixed so that the hollow fiber membranes 7 are focused in a substantially straight line, and the end face of the hollow fiber membrane 7 in the fixed part 4 is opened, so that The end face of 7 is sealed.
As the material for the fixing part, liquid resins such as polyurethane, epoxy resins, unsaturated polyester resins, and silicone resins are preferably used, and these resins are cast together with the bundle of hollow fiber membranes to integrate them. At this time, inorganic substances such as clay, talc, and silica can also be added to the resin. Furthermore, it is also possible to use a metal or resin molded product as the outer frame of the fixed portion. It is important that the fixed part 4 is bonded to the cap body 3 in a fluid-tight manner, but the adhesive may be the same or different from the material of the fixed part. The fixing portion 5 is effective for uniting the entire hollow fiber membrane bundle in order to prevent bending of the hollow fiber membrane 7 during water supply, and may be shaped like a disk, hemisphere, or cone. It is also possible to provide a water inlet in a part of the fixed part.

The perforated cylindrical body 6 is effective for preventing damage to the hollow fiber membrane 7 due to water pressure when handling the membrane element 1 and starting filtration, and is made of plastic net, expanded metal, etc. into a cylindrical shape. ,
Any material having a buckling strength of 1 kg or more and rigidity can be used, and the size, number, etc. of the holes are not limited. Although the position of the feed water inlet 8 is not particularly limited, it is preferable to take care that the feed water is fed in a direction parallel to the hollow fiber membrane 7 to prevent damage to the hollow fiber membrane 7 during filtration. There is little chance.

Various types of hollow fiber membranes can be used in the hollow fiber membrane module of the present invention. For example, hollow fiber membranes made of various materials such as polyolefin, polysulfone, polyvinyl alcohol, and polyacrylonitrile can be used. However, in order to further reduce the generation of fine particles from the module, it is necessary to consider not only the module structure but also the cleanliness of the inner surface of the hollow fiber membrane that comes into contact with the filtrate. Preferably, the material has a skin layer on its surface.

〔Effect of the invention〕

As described above, according to the hollow fiber membrane module of the present invention, it is possible to prevent contamination of the filtrate contact surface during module manufacture, and the membrane element can be easily replaced without contamination. As a result, the number of fine particles in the filtrate can be reduced, making it an extremely suitable module suitable for precision filtration applications such as terminal filters for producing ultrapure water.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the external pressure filtration type hollow fiber membrane module of the present invention.

Claims (1)

[Claims] 1 One end of the hollow fiber membrane is fixed in a sealed state, and the other end is fixed in a fixed state in an open state, and
A cap body having a filtrate outlet and a flange is adhesively fixed to the fixed part on the other end side, and a hollow fiber membrane element in which both fixed parts are fixed to both ends of a rigid perforated cylindrical body, and the membrane An external pressure filtration type hollow fiber membrane module comprising a flange for supporting a cap of an element, an inlet and an outlet for supply water, and a housing capable of accommodating at least a membrane portion of the membrane element. 2. The external pressure filtration hollow fiber membrane module according to claim 1, wherein the hollow fiber membrane has a skin layer on at least the inner surface.