JPS6352523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating the end face of a hollow fiber membrane separation module, and more particularly to a method for completely and easily repairing leak spots on the end face of the module.

Hollow fiber membrane separation modules are widely used for processing various industrial liquids and gases, for medical purposes, and as equipment for producing ultrapure water.

As such hollow fiber membrane separation module,
For example, the hollow fiber membranes and the cylindrical case housing them are adhesively fixed at both ends with casting resin,
It is known that a hollow fiber membrane is opened at the end face of the casting resin.

When separating liquids using the above module, the stock solution is supplied from one open end surface of the hollow fiber membrane, the concentrated liquid flows out from the other open end surface, and the obtained permeate is placed in a cylindrical case. The permeate is discharged from the permeate outlet. In this case, the stock solution and concentrated solution must not leak to the permeate side, and if leakage occurs, the performance of the module will deteriorate and it will become unusable. The cause of this leak is often due to poor adhesion between the casting resin, hollow fiber membrane, and cylindrical case at the ends, and therefore, it is necessary to repair this poor adhesion.

Conventionally, as the above-mentioned repair methods, repair methods using decompression method (Japanese Patent Application Laid-open No. 135675/1982) and repair method using pressurization method (Japanese Patent Application Laid-Open No. 138874/1989) have been proposed.
In these methods, the opening of the hollow fiber membrane is blocked during repair, so the end must be further cut to open the hollow fiber membrane, which is very complicated and disadvantageous in terms of cost. It had the disadvantage of being

The present invention has been made to solve the drawbacks of the prior art, and provides a method for repairing the end face of a module without blocking the opening of the hollow fiber membrane.

That is, the present invention provides a module in which a plurality of parallel hollow fiber membranes are bonded and fixed to each other by casting resin at both ends, and a casting resin end face on the opening side of the hollow fiber membranes is coated as a transfer material. A method for treating the end face of a hollow fiber membrane separation module, characterized in that the repair casting resin is transferred to the end face of the casting resin by abutting a mesh screen coated with the repair casting resin. It is.

The transfer material used in the present invention is made by uniformly applying a repair casting resin to a mesh screen so that the mesh (hereinafter referred to as opening) is kept clogged with the casting resin. The repair casting resin can be transferred to the end face of the casting resin of the module.

By bringing the thus formed transfer material into contact with the end face of the casting resin on the hollow fiber membrane opening side of the module, the repair casting resin held in the opening part of the screen is brought into contact with the end face of the casting resin of the module. Upon contact, it is peeled off from the opening portion, transferred to the end surface, and filled in the defective adhesion area. On the other hand, at the opening of the hollow fiber membrane, the repair casting resin does not come into contact with the opening and is held in the opening part, so it does not enter the opening.

The hollow fiber membrane to which the present invention is applied has an inner diameter of 20 to 3000 μm, usually 500 to 1500 μm, and a membrane thickness of 5
~1000 μm, usually 100 to 500 μm.

The mesh screen used as the transfer material in the present invention has a uniform opening, can hold the repair casting resin in the opening, and can transfer the repair casting resin to the end face of the module casting resin. Although it varies depending on the inner diameter of the hollow fiber membrane, a mesh having an opening of about 20 to 300 μm, preferably about 70 to 130 μm is used, for example, a mesh made of nylon, polyester, etc. with a thickness of 50 to 200 μm. A certain degree is used. If the opening part is too small, it will be difficult to separate the repair casting resin held in the opening part from the opening part when it comes into contact with the end face of the resin casting resin, making it difficult to transfer it to the end face of the resin. If the opening part is too large, the repair casting resin may enter the opening of the hollow fiber membrane and block the opening, which is not preferable.

The above-mentioned repair casting resin may be any resin that can be held in the opening part of the screen and peeled from the opening part, and usually has a viscosity of 200
~10000 cp, preferably 500~2000 cp can be used. If the viscosity is less than 200 cp, it will be difficult to hold the repair casting resin in the opening part, and if the viscosity is more than 10,000 cp, it will be difficult to hold the repair casting resin in the opening part. There is a possibility that even the repair casting resin in contact with the thread membrane opening may peel off and the casting resin may enter the opening. The material of the repair casting resin is not particularly limited, but it is preferable to use the same type of casting resin as the module, such as epoxy resin or urethane resin.

Furthermore, in the present invention, when the transfer material is brought into contact with the end face of the casting resin of the module, if the outside of the hollow fiber membrane is made to have a reduced pressure (usually 300 to 750 mmHg),
The repair casting resin can be more effectively filled into areas with poor adhesion.

As described above, according to the present invention, a mesh screen coated with a repair casting resin as a transfer material is brought into contact with the end face of the casting resin on the hollow fiber membrane opening side of the module, so that the hollow Since the repair casting resin can be transferred to the end face without blocking the thread membrane opening, there is an advantage that a defective adhesion site on the end face of the module can be completely and easily repaired.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 3,700 polysulfone hollow fiber membranes with an inner diameter of 500 μm and a membrane thickness of 250 μm were housed in a vinyl chloride cylindrical case with an inner diameter of 77 mm and a length of 1077 mm, and both ends were adhesively fixed with epoxy resin. After the resin solidified, the hollow fiber membranes were A hollow fiber membrane separation module was obtained by cutting both ends so that they were open.

When a leak test was conducted by supplying pressurized gas to the outside of the hollow fiber membrane of this module, it was found that the pressure of the pressurized gas decreased and a leak point occurred.

Therefore, a mesh screen with an opening part of 62 μm and a thickness of 66 μm (manufactured by NBC, product name: No.-250T)
Then, a transfer material is made by applying an epoxy resin with a viscosity of 500 cp as a repair casting resin to the opening part so that it remains clogged, and then the transfer material is brought into contact with the end surface of the casting resin of the module. The epoxy resin was transferred. At this time, the pressure on the outside of the hollow fiber membrane was reduced to 300 mmHg. After the epoxy resin was transferred to the end surface of the casting resin, the transfer material was removed and the epoxy resin was solidified.

A leak test was conducted again on the module whose end face had been treated as described above, but no leakage points were observed. Further, the openings of the hollow fiber membranes were not blocked in any way.

Claims (1)

[Claims] 1. An opening part of 20 to 300 μm is formed on the end face of the casting resin on the opening side of the hollow fiber membrane of a module in which the hollow fiber membranes are adhesively fixed to each other with casting resin at both ends of a plurality of parallel hollow fiber membranes. An end face of a hollow fiber membrane separation module characterized in that the repair casting resin is transferred to the end face of the casting resin by abutting a transfer material formed by coating a repair casting resin on a mesh screen having the above-mentioned mesh screen. Processing method.