| 摘要 |
A filter comprises a porous material 12 defining a passage 13. The porous material has an inner surface (6, Fig 1) having finer pores than an outer surface (7, Fig 1). The inner surface (6) is castellated or stellated, and comprises an odd number of castellations or stellations. Preferably the filter is formed from a ceramic and porous material or the inner surface is provided with a porous surface film that is permeable and allows separation of permeate and retentate. The filter may be arranged as a multi filter or multi tube construction. Advantageously the castellated/stellated surface induces turbulence in order to minimize deposited particulate matter adhering to the inner surface. |
