| 摘要 |
PURPOSE:To obtain an ultrafiltration device which satisfies filtration accuracy and permeation speed by using porous glass tubes formed by subjecting phase-separated glass tubes to an acid treatment from one of the inside and outside surfaces thereof and holding the deposit of a silica gel partially to the surface on the side opposite from the acid treatment as a filter body. CONSTITUTION:Either of the inside and outside surfaces of the glass tubes subjected to the phase sepn. by a heat treatment, for example, the outside surface is brought into contact with an acid soln. Na2O and B2O3 existing in the parts to be formed as fine pores elute into the acid soln. and the SiO2 remains as the silica gel 23 in the holes 24. The inside surface forms an inside layer 1A' where the silica gel remains and deposits and the outside surface side forms the outside layer 1A'' of the fine pore skeleton of the porous glass thin inside layer 1A' is formed in the fine pores in the subsequent drying stage. Such porous glass tubes 1A are bundled and fitted in a casing 10 by which the ultrafilter body 14 is manufactured. The good filtration accuracy of the porous glass tubes 1A is maintained by the thin inside layer 1A' on the inside surface and the filtration speed is maintained by the outside layer 1A'' without being decreased so much. Both functions are thus practicably satisfied by said glass tubes.
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