US Patent 9700672 Continuous multi-fluid pump device, drive and actuating system and method

A selector valve for a medical fluid delivery device is disclosed. The valve includes a valve bore in fluid communication with an outlet channel, first and second outlet ports, and a selector valve body which includes a valve stem located within the valve bore and having a flow passage. The selector valve body is adapted to place the flow passage in fluid communication with one of the first outlet port, the second outlet port, and a shut-off position. Further, the selector valve body includes a sealing arrangement having an elastomeric core disposed within a thin-walled valve stem which comprises a thin cylindrical sidewall in direct contact with the valve bore. When the elastomeric core and the valve stem are subjected to internal fluid pressure, the thin cylindrical sidewall of the valve stem expands outward to increase a sealing force between an outer diameter of the valve stem and the valve bore.