Fluid dosing device with viewing glass - having piston with at least one fluid opening with valve element each side

摘要

An arrangement for dosing of fluids, e.g. using a time controlled pump, has a viewing glass (1,2,3) mounted approximately vertically in the dosing tube for dosage monitoring. The dosing tube is filled with fluid between the viewing glass and the outlet. It is improved w.r.t. similar arrangements so as not to require a suction pump and an associated controller. A piston (6), inside the viewing glass has a fluid opening (8a) with a valve body (9,10) on either side. The lower valve body (10) seals the opening (8a) only when the pump press. cuts in the flow direction. The upper valve body (9) seals the opening by the wt. of the fluid above it acting against the flow direction. The dosing tube has rigid sections (12,13) either side of the glass which carry piston guide rods (11).