Posts Categorized: Technical Papers

A 150,000 PSI Dynamic Pressure Calibrator

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This technical paper describing the methods, concepts, and operation of a 150,000 PSI dynamic pressure calibrator was originally written in October of 1987. All tests were performed by the US Army Ballistic Research Lab at the Aberdeen Proving Ground in Maryland.    Abstract: A positive step pressure generator suitable for the dynamic calibration of ballistic pressure […]

A Contemporary Version of the Bridgeman-Birch 30 Kilobar Apparatus

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A Contemporary Version of Bridgman-Birch 30 kb Apparatus This paper briefly describes the basic Harwood apparatus, particularly its deviations from the original Bridgman model and the elaboration thereof by Birch for uses with gases at high temperature.  Nearly all the physical measurements made by Bridgman at 12 kb can be made with this equipment at […]

Hydraulically Driven Pumps

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Hydraulically Driven Pumps Excessive torque, side thrust, and friction make crank-driven pumps cumbersome and expensive at high pressures. But in hydraulically driven pumps, these effects are eliminated or minimized and higher pressures can be attained. Also, longer strokes are characteristic; therefore, rates of stress buildup are reduced in such areas as check valves and packings, […]

Piston Gauges as a Precise-Measuring Instrument

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Piston Gauges as a Precise Pressure Measuring Instrument The errors which must be considered for accurate measurements of pressure with piston gauges are discussed. Harwood’s unique design of piston gauge which permits the operator to control the clearance between the piston and cylinder at any operating pressure is described. Instrument errors are thus substantially reduced, particularly […]