Constant volume piezometers CVP

The values of, 4 as a function of temperature and pressure have been tabulated by Rogers and Pitzer (1982) up to 300 °C and 100 MPa and by Helgeson and Kirkham (1974) in the range 0-650 °C and from saturation to 500 MPa. The 

The sample pressure is determined with a deadweight gauge (7) and diaphragm-type null detector (9, 10) with an accuracy of around 0.002 MPa. 

Abdulagatov reported density measurement uncertainty around 0.1% in the temperature range 523-673 K and pressures up to 100 MPa (Abdulagatov et al., 1996a) using this type of piezometer. Errors ranging between 0.2% and 0.7% were reported by some authors (Shmulovich et ah, 1979) at 450-500 MPa using similar apparatuses. 

The piezometer (11) is located vertically in a liquid thermostat (12) having a pump stirrer (1), bottom heater (3), side heater (13), temperature regulator with thermocouple (15) and microheater (16). The temperature is measured with a platinum resistance thermometer (14). 

The reported uncertainty in density determination using this piezometer was 0.06% up to 573 K and 40 MPa. 

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