Patent ID: 6148716
Filing Date: 2000-11-21
Classification: F01B,F04B

Abstract:
A positive displacement pump comprising:a housing;a plurality of pistons;a drive element continuously unidirectionally rotatable relative to the housing;a rigid compression member connected to each of the pistons and reciprocatably moveable with the pistons relative to the housing; andtension means connected between the drive element and each of the pistons for reciprocating the pistons in response to the continuous unidirectional rotation of the drive element, the tension means including a tension element permanently maintained in tension so as to continuously exert radially inward force on the compression member to permanently maintain the compression member in compression so as to continuously exert radially outward force on the pistons connected thereto;each piston being driven inwardly by the drive element through force exerted through the tension means and being driven outwardly by the drive element through force exerted through the tension means to and through the rigid compression member.