| 摘要 |
<p>A membrane filter (12) having predetermined controlled porosity and the method for making such a membrane filter (12). The membrane filter (12) has a plurality of pores, with each of the pores having a predetermined size from top to bottom located at predetermined locations across the membrane filter (12). The pores each have a tapered configuration. The membrane filter (12) is made by a method which utilizes probes (20) having tapered piercing tips that pierce the membrane (12) to form the pores. Preferably, a plurality of probes (20) are nested together so that a predetermined number of pores can be made with one reciprocation. The method permits membranes (12) to be formed from PFA, perfluoralkoxy, as well as from all presently used membrane filter materials.</p> |
