Metering injection pump combination - has metering piston hydraulically driven by main piston and separating main from metering cylinder

摘要

The combined metering/injection pump is intended for controlled admixture of a metered e.g. chemical to a main liquid and comprises a main pump (1) with main piston (5) reciprocating in a main cylinder (6) with inlet (7) and outlet (21), a valve (11) controlling the main pressure and a metering piston (13) reciprocating in a metering cylinder (17) with inlet (27) and outlet (22) connected with the main outlet (21). The main piston hydraulically operates the metering piston, the hydraulic fluid being the main liquid, and the metering piston separates the main from the metering cylinder. This separation may have a limited clearance. The metering piston may be co-axially connected with a cylindrical slide (12) which acts as the piston guide.