The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 03, 1979
Filed:
Mar. 18, 1977
Applicant:
Inventor:
Dietmar G Nussbaumer, Gottingen, DE;
Assignee:
Sartorius Membran-Filter GmbH, Gottingen, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B01D / ;
U.S. Cl.
CPC ...
210 / ; 210 / ; 2105 / ; 264 41 ;
Abstract
An asymmetrical permselective cellulose triacetate membrane has outstanding properties for desalination of seawater by reverse osmosis. It is made by casting a solvent solution of the cellulose triacetate in a solvent mixture of at least 40% acetone, a solvent for the triacetate and a swelling agent for the triacetate. The swelling agent, preferably formamide, must be added as the last component of the solution. After exposing the cast solution to evaporation for 2-90 seconds, it is precipitated in cold water, and then optionally tempered at 50.degree.-100.degree. C. in water which may contain a modifying agent, and dried.