Pump.

摘要

A pumrp for metering two fluids comprising a cylinder having a first and second inlet conduit and an outlet conduit, means (33) for closing the communication between the cylinder (2) and the first inlet conduit (6) and between the cylinder (2) and the outlet conduit (7) alternately, there being present inside the cylinder (2) a first floating solid piston (9) for drawing in a primary fluid from the first inlet conduit (6) and discharging it into the outlet conduit (7) and a second piston (27) for drawing in a secondary fluid from the second inlet conduit (25) which piston has at least one port provided with one or more valves (30) through which the secondary fluid can flow to occupy the space (8) between the two pistons where it can transmit the motion of the second piston to the first piston, and a by-pass (22) for conveying secondary fluid from the space between the pistons to the outlet conduit (7).