Abstract: A pressure measuring section is arranged between a pipe section connected with an injection pump and a pipe end section or portion. The pressure measuring section is provided with a pressure measuring location which is determined by a measuring chamber arranged internally of a housing portion. Within such measuring chamber or compartment there is located a pressure-impinged portion of a pressure measuring transducer which generates electrical signals in accordance with the pressure prevailing in the injection medium. These electrical signals are inputted by a cable to a signal evaluation location. The measuring location is located in close proximity to an outlet opening of the pipe end portion or section. Between this outlet opening and the pressure measuring location there is arranged a packing device which seals the annular or ring-shaped compartment between the pipe end section and the wall of the borehole.

Abstract: Analogue measuring value signals, generated in a throughflow measuring device, are infed to a computer by means of an analogue-digital converter. The computer adds the received digital signals and produces at regular time intervals, for instance every three seconds, an output signal corresponding to the total conveyed quantity. This output signal serves to control a display device and a printer. In the display device there is displayed the total quantity of the conveyed material during a certain time span. On the other hand, the computer forms a mean or average value signal from digital signals received within a predetermined time span, for instance likewise every three seconds. This mean value signal is characteristic for the momentary throughflow of the material during this time period. This mean or average value signal likewise serves to control the display device and the printer. In the display device there is thus also displayed the momentary throughflow quantity.

Abstract: An apparatus for the essentially uniform feed or conveying of a fluent or flowable medium by means of to-and-fro moving feed or conveying pistons, wherein there are provided at least two single-acting feed pistons. Each of the feed pistons is equipped with a forward drive and a return drive. The return velocity is greater than the forward velocity. The forward drive and return drive are driven with a phase shift such that the terminal or end portion of the feed stroke of the one feed pump overlaps the starting portion of the feed stroke of the other feed pump.

Abstract: An apparatus for the control of a fluid medium incorporating a fluid medium actuated switching element which can be reversed between two switching positions by means of two actuation elements working in the opposite sense. The actuation line or conduit of each actuation element is controlled by a normally closed shutoff valve, each actuation element is connected at its actuation line between the shutoff valve and a throttle location.