POSITIVE DISPLACEMENT PUMP PROVIDED WITH BOTH DIRECTIONS TIGHT SEAL

摘要

PROBLEM TO BE SOLVED: To provide a new improved and miniaturized positive displacement pump especially suitable for the use for a dosing set in a vein and other treatment device which can be manufactured simply at a low cost. SOLUTION: A simple tight seal of a circumferential direction is used to hold a pumped fluid and prevent its loss and leak. A long and slender space 8 is partitioned inside and a spring sheet material 20 is arranged adjoining to an opening 24 at one end of the space 8. The sheet 20 has the opening 24 positioned so as to match with the opening 24 of the space 8. Two branch edges 20a, 20b are formed on the sheet 20 so as to surround the opening 24 and one branch edge is extended toward the space 8 and other branch edge is extended outward from a housing 4. A long and slender shaft is arranged in the opening slidably and its one end is extended in the space 8 and other end is extended outward from the housing 4 and connected to a reciprocating drive mechanism. The cross section shape and size shape of the opening 24 are same as those of the shaft.