Metering device for the measurement and dispensing of a predetermined volume of an incompressible medium

摘要

A metering device for the measurement and dispensing of a predetermined volume of an incompressible medium. The metering device can be used on automatic machines for dispensing metered portions of beverages. A piston (3) is guided in a first hollow cylinder (1 - see Fig. 1). The hollow cylinder (1) is bounded at one end by a closing plate (2) and at the other end by an annular plate (5). One working surface (3a) of the piston (3) and the closing plate (2) define a metering space (1a) and the other working surface (3b) of the piston (3) and the annular plate (5) define a resetting space (3c). Rigidly arranged on the piston is a second hollow cylinder (4) which is guided in sealing fashion by the annular plate (5) and is connected to a base plate (9). Arranged within the second hollow cylinder (4) is a 3/2-way valve (7). The device operates on the differential piston principle. For the purpose of filling, medium flows into the metering space (1a) via a feed line (6), the 3/2-way valve (7) and a conduit (11). For the purpose of emptying, the medium flows through the feed line (6) into the resetting space (3c) and out of the metering space (1a) to the drain line (8) via the 3/2-way valve (7). The accuracy of metering is independent of pressure fluctuations in the feed line. <IMAGE>