Abstract: An automatic circuit is provided for a switching motor of electromechanical, self-stabilizing balance having electromechanical compensation. An analog transducer produces an analog measured value which triggers operation of a switching motor whenever an upper or lower limiting value is exceeded, the analog measured value being applicable to a display device. A computer, which actuates a control circuit for the switching motor and the display is connected to the analog transducer via an analog-digital converter, the converter being operatively arranged to derive fine information which is fed to the computer and high-speed coarse or preliminary information which is likewise supplied to the computer ahead of the fine information, which triggers said switching motor in event one or more limiting values is exceeded.

Abstract: An asymmetrical ultrafiltration membrane based on cellulose hydrate which may be dried without destructive shrinkage and which has been saponified without reduction in flow-through or separation performance is prepared by adding hydrophobic synthetic silicic acid to a casting solution based on cellulose triacetate optionally partially substituted by cellulose diacetate, and then casting the cellulose acetate membrane and saponifying to the cellulose hydrate form.

Abstract: Apparatus for mass transfer between fluids, comprises two permeable membranes with a porous membrane support sandwiched therebetween, all pleated together with an accordian pleat to form a pleat package, and sealed in a casing to define three flow channels from one end of the casing to the other, to form a filter having a large filter area in a minimum amount of space for use as a dialyzer or as an ultrafilter in the treatment of blood. By selection of different membrane materials, the apparatus may also be used for oxygenation of blood, and three different fluids, including both gases and liquids, may be treated.