Abstract: A magnetic drive metering pump in which a movable thrust member is fixed to a diaphragm and is axially movable in a magnet shroud. The thrust member, on electrically actuating the magnet shroud, is drawn into the magnet shroud against the force of a recuperating spring, and after deactivating the magnet shroud, is returned to a starting position. The diaphragm cooperates alternately with an outlet and an inlet valve to produce a pump stroke in a pump metering head. The magnetic drive metering pump has a reference element associated with the thrust member and diaphragm, the position of which reference element is detected by a positional sensor. The positional sensor provides a signal which has a fixed relationship to the position of the reference element, and the motion of the thrust member is controlled by a control circuit such that it follows a predetermined nominal profile.

Abstract: A magnetic drive metering pump in which a movable thrust member fixed to a connecting rod is axially movable in a longitudinal axis in a magnet shroud anchored in a pump housing so that the thrust member with the connecting rod, on electrically driving (actuating) the magnetizing coil, is drawn into the magnet shroud against the force of a recuperating spring, reducing an air gap between the thrust member and an inner face of magnetic shroud, into a bore in the magnet shroud and after deactivating the magnet the thrust member is returned to the starting position by the recuperating spring so that the thrust member and an elastic displacement member actuated thereby on carries out an oscillating motion continued activation and deactivation of the magnetizing coil, which diaphragm cooperates alternately with an outlet and an inlet valve to produce a pump stroke (pressure stroke) and a priming stroke in a metering head arranged in the longitudinal axis.

Abstract: A sensor for thermal mass flowmeters is described herein. The sensor includes a plate-shaped, thin-film resistor and a cylindrical holder into which the resistor is fastened. In order to fasten the thin-film resistor in a mechanically stable manner, the end surface of the holder is provided with a pocket hole which closely matches the cross section of the thin-film resistor. The thin-film resistor is suitably inserted into this pocket hole and fastened therein with an adhesive agent.