Patent ID: 6129526
Filing Date: 2000-10-10
Classification: F04B

Abstract:
A metering pump comprising:a drive compartment defining a drive chamber, the drive chamber having an inlet and an outlet for a main liquid;a drive piston moveably arranged in reciprocating translational motion in the drive chamber;distribution means controlling movement on the drive piston under action of the main liquid;a metering compartment defining a metering chamber, the metering chamber having an inlet and an outlet for an auxiliary liquid, the outlet for the metering chamber being separated from the outlet of the driving chamber;a metering piston arranged in the metering chamber, the metering piston being driven by the drive piston;a frustoconical sealing member arranged with its small base facing the drive compartment, an extension of the metering piston, having a diameter smaller than a body of the metering piston, passing through the frustoconical sealing member, the extension and the frustoconical sealing member forming a suction valve;suction-delivery means arranged on the metering piston; andan extendable tubular element having a first end sealingly fastened to a tubular part that is fixed to the drive chamber, the metering chamber being connected to the drive chamber via the tubular part, a second end of the extendable tubular element sealingly fastened to the metering piston, wherein a flow of the auxiliary liquid is supplied by the metering compartment substantially proportional to a flow of the main liquid.