Patent ID: 8267667
Filing Date: 2012-09-18
Classification: F04B

Abstract:
1. A magnetic drive metering pump comprising a movable thrust member, fixed to a connecting rod, 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 activating a magnetizing coil ( 29 ) to magnetize a magnet in the magnet shroud, is drawn into the magnet shroud against the force of a recuperating spring into a bore in the magnet shroud, reducing an airgap between the thrust member and an inner face of the magnet shroud, and after deactivating the magnet the thrust member is returned to a starting position by the recuperating spring so that the thrust member and spring actuated thereby carries out an oscillating motion on continued activation and deactivation of the magnetizing coil, said connecting rod being interconnected to a flexible pumping diaphragm such that the diaphragm oscillates with the connecting rod, said diaphragm cooperating alternately with an outlet and an inlet valve to produce a pump stroke and a priming stroke in a metering head arranged in the longitudinal axis, wherein a reference element ( 35 ) is associated with a module constituted by the thrust member ( 20 ) and connecting rod ( 19 ), a position of which reference element is detected by a positional sensor ( 36 ), wherein the positional sensor provides a signal (X I ) determined and monitored during the whole pump stroke and priming stroke, wherein the signal (X I ) has a fixed relationship to the position of the reference element, and wherein a control circuit utilizes the signal (X I ) to adjust the motion of the module formed by the thrust member ( 20 ) and the connecting rod ( 19 ), within a predetermined nominal profile ( 38 ), wherein the reference element ( 35 ) influences a path of light from a light source ( 33 ) to the positional sensor cooperating therewith ( 36 ), wherein the positional sensor is fixed on the magnet shroud and operates in a light sensitive manner, wherein the reference element ( 35 ) is a shadow-producing body or a shadow producing contour and the positional sensor ( 36 ) arranged on the magnet shroud consists of an optical receiver ( 32 ) in the form of a series of light sensitive charged coupled devices (CCD).