HIGH-PRESSURE MEASUREMENT WITH SIMPLE PISTON GAUGE IN STATIC CONDITION

This paper describes the characterization of the newly developed pisto n gauge pressure standard at the National Physical Laboratory (NPL), w ith particular reference to its fall rate, engagement length of the pi ston and the deceleration rate for the measurement of hydraulic hydros tatic pressure up to 60 MPa. The low pressure effective area of the ga uge derived from its dimensional measurements when compared with the v alue obtained by its direct calibration against NPL transfer pressure standard agrees within 0.025%. The pressure gauge is quite stable, rep roducible and has a sensitivity of 3 ppm. Though the theoretically cal culated value of the pressure coefficient is low as compared to the ex perimentally observed one in its absolute terms, the pressure dependen t effective area agrees within +/-0.025% over whole of the pressure ra nge which is well within the uncertainty statement of the two independ ent techniques used.