Fluid metering device

Claim 1

IN A FLUID METERING DEVICE PROVIDING A CHAMBER, AN ELONGATED METER ELEMENT, AND MEANS FOR SUPPORTING SAID ELEMENT FOR MOVEMENT THEREOF LENGTHWISE THEREOF WITHIN SAID CHAMBER, SAID ELONGATED ELEMENT HAVING AN EXTERIOR SURFACE OF UNIFORM PERIPHERAL CONTOUR ALONG ITS LENGTH, SAID ELEMENT BEING PROVIDED WITH AN OPEN CHANNEL EXTENDING LENGTHWISE THEREOF, THE COMBINATION WITH SAID METERING DEVICE OF A MEMBER DISPOSED WITHIN SAID CHAMBER AND HAVING AN OPENING THEREIN THROUGH WHICH SAID ELONGATED ELEMENT MOVES LENGTHWISE THEREOF, THE PERIPHERY OF SAID OPENING ENGAGING SAID EXTERIOR SURFACE OF SAID ELEMENT AND EXTENDING ACROSS SAID CHANNEL TO DEFINE WITH SAID CHANNEL AN ORIFICE AT DIFFERENT POSITIONS OF SAID ELEMENT IN SAID LENGTHWISE MOVEMENT THEREOF, SAID MEMBER BEING PROVIDED WITH A GROOVE EXTENDING ABOUT AND BEING OUTWARDLY SPACED FROM SAID PERIPHERY OF SAID OPENING OF SAID MEMBER, SAID GROOVE EXTENDING INTO SAID MEMBER FROM A FACE THEREOF TRANSVERSE TO THE LENGTH OF SAID ELEMENT TO DEFINE AN ANNULAR PORTION OF SAID MEMBER INTERPOSED BETWEEN SAID PERIPHERY OF SAID OPENING OF SAID MEMBER AND SAID GROOVE, SAID MEMBER BEING FORMED OF A MATERIAL WHICH COMPRISES A PERHALOGENATED POLYETHYLENE IN WHICH AT LEAST ONE OF THE HALOGEN ATOMS IS FLUORINE TO PROVIDE A SEMI-RIGID RESILIENT INERT ORGANIC PLASTIC HAVING A LOW COEFFICIENT OF FRICTION AND CAPABLE OF PROVIDING FOR SLIGHT ELASTIC YIELDING OF SAID ANNULAR PORTION IN THE RADIAL DIRECTION TO PROVIDE FOR MOVEMENT OF SAID ELONGATED ELEMENT THROUGH SAID OPENING IN ENGAGEMENT WITH THE PERIPHERAL SURFACE OF SAID OPENING WITH AN INTERFERENCE OF FIT, SAID PLASTIC BEING SUFFICIENTLY RIGID SUBSTANTIALLY TO MAINTAIN THE FORM OF SAID MEMBER AND OF SAID OPENING THEREIN SO AS TO MAINTAIN SEALING UPON SAID EXTERIOR SURFACE OF SAID ELONGATED ELEMENT AND WITH SAID ANNULAR PORTION RIGIDLY SPANNING ACROSS SAID CHANNEL, SO THAT THE PERIPHERAL SURFACE OF SAID OPENING ALONG SAID ANNULAR PORTION PRECISELY DEFINES SAID METERING ORIFICE WITH SAID CHANNEL.