Abstract: The invention relates to a method permitting the magnetic properties of ferromagnetic powders which are used for the preparation of heavy media for the float-sink dressing of minerals, to be tested. To this end, the invention provides for the ferromagnetic powder to be magnetized in a magnetic steady field at a field strength within the range 600 to 1000 amperes per cm and the magnetized ferromagnetic powder to be demagnetized in a cyclicly decreasing magnetic alternating field at a field strength within the range 1000 to 1500 amperes per cm. Next, the ferromagnetic powder so pretreated is heaped up, in the center portion of a circular plate made from dielectric material and the circular plate is placed on an iron core-provided coil. An alternating current voltage of 180 to 260 volts is applied to the coil, thereby effecting the occurrence of alternating fields of 180 to 220 amperes per cm in the center portion of the circular plate.

Abstract: The invention relates to a method permitting ferromagnetic powders to be readily tested for their qualification for use in heavy medium suspensions for the float-sink dressing of minerals. To this end, the invention provides(a) for ferromagnetic powder particles with a size within the range 63 to 100.mu. to be admixed with a quantity of a glycerol/water mixture necessary to obtain a heavy medium suspension having a specific density within the range 1.45 to 1.55 g/cm.sup.

Abstract: The invention relates to a method permitting ferromagnetic powders for use in heavy medium suspensions for the float-sink dressing of minerals to be readily tested as to their efficiency in magnetic separation and demagnetization. To this end, the invention provides(a) for a heavy medium suspension specimen to be removed from the purification cycle directly downstream of the magnetic separation stage, for it to be freed from impurities by decantation, and its relative sedimentation velocity to be determined with the aid of a sedimentometer;(b) for a heavy medium suspension specimen to be removed from the purification cycle downstream of the demagnetization stage, for it to be freed from impurities by decantation, and for its relative sedimentation velocity to be determined with the aid of a sedimentometer; and(c) for the heavy medium suspension specimen according to (b) to be demagnetized in a cyclicly decreasing magnetic alternating field with a maximum field strength which is 1.1 to 1.

Abstract: A radial piston pump has a housing bounding a suction chamber therein and provided with a plurality of pressure ports spaced from one another in circumferential direction of this housing, and with at least one suction port. A plurality of valve units spaced from one another in the circumferential direction of this housing are provided, each of which includes a pressure valve element located in a respective one of the pressure ports and a sleeve member mounted in the same pressure port radially outwardly of the pressure valve element so as to form, together with the latter, a pressure chamber inwardly of and communicating with the pressure port. A plurality of circumferentially extending channels are formed in this housing and intersect the respective pressure chambers.

Abstract: The radial pump preferably for use in connection with a hydraulic clamping device includes a plurality of pumping elements enclosed in a housing and cooperating with a corresponding pluraity of discharge valves. A multiway control valve controls the delivery of pressure fluid to a load port in such a manner that during the actuation of the load the outlet of all discharge valves are united to deliver the entire flow of pressure fluid into the load port, whereas when the load is maintained under a constant pressure, only one pumping element delivers discharged fluid via a single discharge valve into the load port and the remaining pumping elements deliver their output into the reservoir.

Abstract: A process for the incorporation of active materials into silicon dioxide-containing carrier materials, comprises encapsulating the active material with liquid polyalkoxysiloxane, polyorganoalkoxysiloxane or a mixture thereof and subsequently effecting hydrolytic polycondensation of the siloxane. The resultant enveloped active material has readily controllable release properties.

Abstract: For filling and adjusting double-membrane cassettes acting as link members in piston metering pumps, the sealing surfaces of the membranes are first coated with a resilient pressure-deformable cement. The membrane cassette is introduced still unclosed into a thermostat where an adjustable, uniform pressure is applied to the upper membrane. The membrane cassette is then filled under an excess pressure of from 0.2 to 1 atm. and closed. After closing, the membranes of the cassette are brought into plane-parallel alignment in an evacuation unit.