Abstract: The process for the visible marking of carrierless polymeric membranes for filtration purposes and for the reverse osmosis is characterized in that the marking symbols are first of all printed onto the casting support, onto which subsequently the casting mass is poured which serves for the production of the membrane. During the removing of the pre-solidified, solidified or finished membrane from the casting support, the printing dye which has an outline corresponding to the marking symbols, is taken up by the membrane and is taken along by the latter from the casting support. Preferably, the printing dye which had been imprinted onto the casting support when the membrane casting mass is poured on, has at least dried in a wipe-proof manner and, in this state, is soluble in the solvent-system of the membrane casting mass.

Abstract: A backpressure grid plate is provided for a pressure filtration system of the type comprising a housing with an inlet and outlet for conducting fluid to be treated, a filter disposed in the housing between said inlet and outlet, and a backpressure grid means arranged between the filter and the inlet. The backpressure grid means comprises a plate containing minute openings which are equal in size and distributed unevenly over the surface area of the plate in such manner that the surface distribution density of the openings is lowest within an inner impact area of the plate which receives inflowing fluid to be filtered and is highest within a proximity area of the plate located immediately adjacent to and surrounding the impact area. The surface distribution density of the openings within an outer area surrounding the proximity area is lower than that of the proximity area and higher than that of the impact area.

Abstract: A housing for single-use pressure filtration units comprises upper and lower parts. A filter element is to be clamped between the housing parts. The upper housing part, preferably molded in one piece of synthetic material, includes a plurality of radial ribs which hold the filter element down, and a baffle disk supported solely by the ribs. The disk is spaced beneath the axial inlet duct to prevent direct impingement of axially incoming pressurized fluid against the filter element. Only some of the ribs support the disk, the remaining ribs terminating short of the disk to promote uniform radial distribution of fluid deflected by the disk. Radially inner ends of the disk support ribs are inclined downwardly and inwardly and act in funnel-like fashion on the inflowing fluid.

Abstract: A high pressure diaphragm test cell includes upper and lower parts. A clamp assembly is provided which enables the cell parts to be clamped together or released by a single person. The clamp assembly includes a carrier frame connected to the upper cell part. A vertical carrier pin extends downwardly from the carrier frame. A pair of clamp ring parts are connected to the carrier pin for rotation in a horizontal plane. A fastener extends tangentially relative to the free ends of the clamp parts for tightening the clamp parts against the cell parts. The fastener includes a screw rotatably carried in one of the clamp parts and threaded into the other clamp part. The screw has stop plates which engage the one clamp part to aid in separating the clamp parts when the cell parts are to be disassembled.

Abstract: A pressure filtration apparatus including an upper portion with an inflow channel and a discharge channel for the concentrate and a lower portion with a filter support and a discharge channel for the filtrate, the upper and lower portions being releaseably connectable with one another while forming a pressure space. The apparatus contains a distributor plate whose underside is disposed parallel to the upper side of the filter and snugly above the latter while forming an intervening space, and in the center of which is an opening for the concentrate discharge channel. The outer edge of the distributor plate forms a small annular opening which extends all around closely against a basically vertically interior of the pressure space. The top side of the distributor plate has a peripherally raised outer edge which while forming a narrow annular clearance extends to close up against a downwardly pointing horizontal interior wall of the upper portion.

Abstract: A pressure filtration cell includes a reservoir for liquid to be filtered, a filter at the bottom of the reservoir, and a manually actuable pump for supplying compressed air. The pump is detachable from the reservoir. The air is introduced near the bottom of the reservoir closely adjacent the filter so as to create turbulence in the liquid and across the filter. The turbulence is of a pulsating nature due to the intermittent operation of the pump. Thus, the pump is easily portable for use anywhere and creates a "dynamic" filtration process even without a mechanical stirrer. If used in a laboratory, the cell can be provided with a rotary, magnetically operated stirrer mounted on a relatively short axle.

Abstract: A compensating plate for a pressure filtration cell including a generally cylindrical liquid-feeding vessel and a base removably connected to the feeding vessel by means of a flanged joint, the removable base forming a filter holder, in which an outer edge of the plate is engaged in a flange between the liquid-feeding vessel and the filter holder and, on its upper side, the outer edge of the plate is sealed against the liquid-feeding vessel by means of a circumferential seal. The compensating plate has a central opening corresponding to the size of a filter placed in the filter holder, the plate having a slight conical depression toward the said opening.

Abstract: A syringe is adapted to overcome a pressure resistance at its outlet as may be provided, for instance, by a filter in communication with the outlet and through which the syringe is to pump a medium, particularly a liquid medium, for filtration. The syringe comprises a first cylinder containing a piston and a piston rod. The piston rod is fixed to a second piston sliding within a longitudinal bore in the first-mentioned piston. The bore and the second piston cooperate to define an air-filled pressure chamber connected to a first cylinder chamber, defined by the first piston and the first cylinder, by a valve. Inward movement of the piston rod produces an over-pressure (e.g. 16 atmospheres) in the pressure chamber to open the valve to apply the over-pressure to the liquid or other medium in the cylinder chamber to overcome the pressure resistance of the filter and enable the liquid to be forced through the filter.

Abstract: Ultrafiltration apparatus employing collodion bag dialyzing means. This apparatus provides a means for accelerating the dialysis process and a cooperative means for obtaining samples of the concentrate from the collodion bag. A displacement body with an axial bore is attached to a tube and positioned within the collodion bag. By displacing fluid volume in the bag, the speed of dialysis is increased. The combination of the tube and displacement body also facilitates removal of samples of the concentrated fluid from the bag.