Filtration equipment

Abstract

Abstract 1436054 Removing metal by lasers; making filters FILTROX-MASCHINENBAU AG 27 March 1974 [3 April 1973] 13624/74 Headings- B3V and B3A [Also in Division B1] A liquid permeable filter plate or tube 10 having a thickness of at least 0À5 mm. is formed' with circular section holes having a minimum diameter of less than 0À3 mm. by means of a laser which has a resonator length of more than 0À5 m. In one embodiment, a stainless steel tube 10 is continuously rotated by a motor 19 and translated along its axis by a screw 14 whilst a laser is pulsed causing holes of 0À15 mm. diameter to be disposed along a helical path, except at the end zones of the tube 10, at a density of 20-400 halos/cm.<SP>2</SP> The laser, which comprises a laser rod 1, an ellipsoidal concave mirror 5, a flash lamp 4 and aligned mirrors 2, 3 defining the resonator length, is pulsed when a photo-cell 23 receives light from a source 21 through one of a number of radial slits in a disc 20 rotating with the tube 10. By moving the focal point of the laser lens system 6-8 relative to the inner and outer tube walls, conical holes having a divergence angle of less than 20 degrees can be produced. Alternatively, the tube is produced with cylindrical holes having conical expansions at one or both ends and a minimum diameter of 0À05-0À25 mm. The tube 10 may alternatively be translated stepwise and rotated stepwise by a stepping motor which also controls the ignition of the flash lamp 4. The filter may comprise a rectangular plate or a circular plate with the holes arranged on a spiral path.

Inventors

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Bibliographic Details