| 摘要 |
An inverted, displacer type piston pump for metering and dispensing liquids in which the cylinder is located beneath the piston and reciprocated via an actuator below the cylinder, and where the piston is held fixed. The liquid ingress and egress to and from the cylinder of the pump is via a cylindrical port through the piston along its cylindrical axis. The pump is designed so that liquid product loss through the pump is prevented without the use of elastomeric or compliant seals in the liquid contact product areas of the pump. In addition, the pump cylinder is capable of being positioned via its reciprocating actuator such that all of the liquid product contact parts are open and accessible to cleaning and sterilizing fluids which may be introduced into the pump through the liquid product supply port of the pump, thereby enabling cleaning and sterilization of the pump without its disassembly. Several embodiments of externally mounted externally operated poppet type valves designed to work in conjunction with the aforesaid or similar pumps are also indicated in which because of no sliding contact between the valve components, there is very little valve wear and a consequently a lower risk of product contamination from particulates. In addition all of the embodiments of the valves permit cleaning and sterilization of liquid product contact surfaces through the use of the aforementioned cleaning and sterilizing agents, without disassembly of the valves. Further, one embodiment of the valve also has a 'suck back' feature within it, so that when the valve shifts from its open to its closed position, a small amount of the liquid product contained in the nozzle and discharge line is pulled back into the valve.
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