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Measurements of the vapor-liquid coexistence curve in the critical region for Refrigerant 114 (C4Cl2F4) were made by visual observation of the disappearance of a meniscus at the vapor-liquid interface within an optical cell. Twenty-three saturated densities between 410 K and the critical temperature were obtained in the density range 290 to 894 kg/m3. The experimental uncertainties of temperature and density were estimated within ±15 mK and ±0.5%, respectively. On the basis of these results, the critical temperature TC and the critical density pC for R 114 were determined to be 418.78 K and 576 kg/m3, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence. The critical pressure PC for R 114 was calculated to be 3.252 MPa by the available vapor-pressure correlation with the present value of TC. In addition, the critical exponent β and the law of the rectilinear diameter near the critical point were discussed.

the measurements of the vapor-liquid coexistence curve in the critical region for R 114 (C2CL2F4) were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Twenty-three saturated densities between 410 K and critical temperature were obtained in the range of densities 290 to 894 kg/m3. The experimental errors of temperature and density were estimated within ±0.5%, respectively. On the basis of there results, the critical temperature Tc and the critical density ρc for R114 were determined to be 418.78 K and 576 kg/m3, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence. The critical pressure pc for R114 was calculated to be 3.252 Mpa by the available vapor-pressure correlation with the present value of Tc. In addition, the critical exponent β and the low of rectilinear diameter near the critical point were also discussed.

Forty-four vapor pressures of Refrigerant 152a (CH3CHF2: 1, 1-difluoroethane) between 273 K and 386 K have been measured in the range of pressures from 0.26 MPa to 4.48 MPa. Ten saturated liquid densities and eleven saturated vapor densities near the critical point have also been measure in the range of temperatures from 370 K to the critical temperature which corresponds to a density variation of 153 kg·m-3 to 635 kg·m-3. The experimental uncertainties of temperature, pressure and density measurements have been estimated within 10 mK, 0, 8 kPa and 0.55%, respectively. On the basis of these results, the critical temperature, critical pressure and critical density of R 152a have been determined to be 386.44K, 4.5198 MPa and 368 kg·m-3, respectively, in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence. In addition, the correlation of vapor pressure and the vapor liquid coexistence curve have also been proposed.

フロン系冷媒R13B1(CB rF3)の臨界域における気液共存曲線を,気液界面の消滅を肉眼で直接観察することにより,温度332～340K,密度376～1108kg/m3の範囲で22点測定した.これらの実測値にもとづいて,R13B1の臨界温度,臨界密度,臨界圧力をそれぞれ340.08K,764kg/m3,3.956MPaと決定した.加えて,臨界指数βを0・340と決定し広い温度範囲にわたり成立するR13B1の気液共存曲線の相関式を作成した.