Patent ID: 8262367
Filing Date: 2012-09-11
Classification: E21B,G01F,Y10T

Abstract:
1. A volumetric fluid metering body comprising: a cylinder having a first end, an opposing second end, and a central axial bore; a first cylinder head at the first end of the cylinder; a second cylinder head at the second end of the cylinder; a piston which slides within the central axial bore and divides the bore into a first chamber and a second chamber the respective volumes of which change as the piston slides within the bore; a first valve in the piston which is configured to open when the piston moves to within a preselected distance from the first cylinder head and when open permits fluid to flow through the piston from the first chamber to the second chamber; and, a second valve in the piston which is configured to open when the piston moves to within a preselected distance from the second cylinder head and when open permits fluid to flow through the piston from the second chamber to the first chamber.