Patent ID: 8142738
Filing Date: 2012-03-27
Classification: B01L

Abstract:
1. A bottle top dispenser for handling liquids, comprising: a piston and cylinder arrangement for the exact take-up and dispensing of liquid volumes, the piston and cylinder arrangement having a cylinder and a piston running, sealed off, in the cylinder and having a piston rod led upward out of the cylinder, a displacement measuring strip arranged directly on the piston rod and which extends axially in a direction of movement of the piston rod, a sensor arrangement fixedly in the dispenser adjacent to the piston rod and having a sensor aligned with the measuring strip and separated from the measuring strip by only a narrow gap, an indicator for indicating the liquid quantity handled or to be handled, and an electronic evaluation circuit for evaluating output signals of the sensor and for activating the indicator, the electronic evaluation circuit being implemented by means of software of a microprocessor or microcomputer, wherein the measuring strip is one of: an optical scale and the sensor arrangement is a high resolution reflected light system, the measuring strip being on the piston rod and the sensor arrangement with the sensor being arranged such that, when the piston rod is in a desired position, a surface of the measuring strip which faces the sensor forms a plane which lies as near as possible to or on a longitudinal mid-axis of the piston rod, a plastic or ceramic strip mixed with magnetic powder, the sensor arrangement being a high resolution system sensitive to magnetic fields, and the sensor detecting a magnetic field of the measuring strip which lies as near as possible to or on a longitudinal mid-axis of the piston rod, and a capacitive displacement measuring strip, the sensor arrangement being a high resolution capacitive measurement system that, when the piston rod is in a desired position, the longitudinal mid-axis of the piston rod lies between a surface of the measuring strip which faces the sensor and the sensor itself, and wherein the displacement measuring strip is positioned in a pocket on the piston rod with an axial stop located on one side in said pocket, said axial stop being a surface facing the piston.