Patent ID: 6886720
Filing Date: 2005-05-03
Classification: F16K,G01F

Abstract:
1. A metering device, comprising: an elongate chamber, the chamber having a shuttle contained within the chamber, the shuttle having a portion which is a substantially sealing sliding fit within the chamber, the shuttle being moveable axially between an initial position and a second position within the chamber, each end of the chamber being comprised of a fluid flow duct through which pressured fluid may enter and leave the chamber, and a valve arrangement means to control flow of fluid to and from the chamber such that, during successive cycles of operation, fluid is supplied to one end of the chamber causing the shuttle to move from the initial position at said one end of the chamber to the second position at the other end of the chamber, thus ejecting a pre-determined volume of fluid from the other end of the chamber, and subsequently fluid is supplied to said other end of the chamber causing the shuttle to move back from the second position to the initial position, ejecting a pre-determined quantity of fluid from the said one end of the chamber, wherein the valve arrangement means comprises a rotary valve rod contained within a valve bare, and a mechanism to rotate the valve rod, the fluid flow ducts from the chamber extending to the valve bore, at least one fluid inlet extending to the valve bore and at least one fluid outlet extending from the valve bore, the valve rod, in combination with the valve bore, defining fluid flow passages which, in one orientation of the valve rod, serve to interconnect a fluid flow inlet, and the fluid flow duct extending to one end of the chamber, while interconnecting the fluid flow duct extending to the other end of the chamber, with a first outlet and, in an alternate orientation, serving to interconnect the fluid flow inlet with the fluid flow duct extending to the other end of the chamber, while connecting the fluid flow duct extending to the one end of the chamber, with a second outlet.