GB786824A - Bacterial analysis filtration and incubation unit - Google Patents

Abstract

786,824. Filters: filtering media. MILLIPORE FILTER CORPORATION. Nov. 16, 1955 [Nov. 22, 1954], No. 32726/55. Class 46. [Also in Group VI] A filter for retaining bacteria and other micro-organisms present in water samples passed therethrough comprises a porous supporting pad of filter paper or felt 28, Fig. 2 (exploded view) resting on a transparent polystyrene or like tray 12 having an outlet port 14 and collar 22, and surrounded by a polychloroprene or like resilient gasket ring 30, a filter film 26 made, for example, by dissolving a cellulose ester in a solvent and evaporating the solution to dryness in a humid atmosphere and resting on 28 and 30, and a frame 32 which holds the edge of the filter film 26 onto the ring 30 when it is itself pressed down by an apertured cap 16 having a taper fit with the tray 12. The ring 30 may be continuous with the pad 28, or the ring 30 and frame 32 may be integral with the tray 12 and cap 16 respectively. In the latter case it is the cap which is recessed round its lower edge, the recess being engaged by the rim of the tray, Fig. 3 (not shown). The tray 12 may be grooved radially and the pad 28 may be replaced by a glass or like disc having radial flutes communicating with a central aperture. The sample may be drawn through the filter by connecting a tube 57, Fig. 9, dipping into the sample, with the inlet port 18 and then piercing the soft rubber stopper of an evacuated bottle 60 with a hollow needle 62 connected to the outlet port 14. Alternatively a sample may be filtered by squeezing it out of a flexible polythene or like container located above and connected to the inlet port 18, Fig. 10 (not shown).