A high-precision device for studying the compression & liquefaction of a gas, determining the critical point & recording isotherms in p-V (Clapeyron) diagrams. The test gas is sulfur hexafluoride (SF6), which has a critical temperature of 318.6 K (45.5°C) & a critical pressure of 3.76 MPa (37.6 bars), allowing for a simple experiment set-up.
The apparatus includes a transparent measuring cell that is highly resistant to leakage & compression. The volume inside the cell is changed via a finely adjustable hand-wheel, the change being indicated by a combination of a fixed & a rotary scale to an accuracy of 1/1000 of the maximum volume. The pressure is generated by a hydraulic system containing castor oil of medically approved quality. The measuring cell & hydraulic system are separated by a cap seal which rolls in as the volume increases. This design means the pressure gradient between the measuring cell & oil chamber is negligible. A manometer measures gas pressure instead of oil pressure W/out taking up any dead space inside the measuring cell. During transitions from the gaseous to the liquid phases & vice versa, it is therefore possible to observe the formation of the first drops of liquid & disappearance of the last gas bubbles.
The measuring cell is enclosed in a transparent water chamber. A circulation thermostat allows the temperature to be maintained at a highly constant value, which can be monitored by means of a thermometer.
Practical indications of the volume, pressure & temperature permit easy recording of p-V or pV-p diagrams providing qualitatively correct results. Pressure & temperature-dependent volumetric corrections also provide quantitatively accurate results comparing favorably W/ standard reference values.
Package Contents:
1 Critical point device filled W/ hydraulic (castor) oil but W/out test gas (SF6). Includes built in safeguarded connection nozzle for MINICAN® gas canisters
1 Oil filling device
1 Angled 1.3-mm hexagonal spanner (for grub screw on rotary scale)
1 Plastic hose, 3 mm internal diameter
1 1/8″ pipe screw connection (SW 11)
1 Grease gun
Additionally required:
Sulphur hexafluoride SF6
Required for periodic degassing or refilling of hydraulic oil:
Castor Oil (1002671)
High Power Vacuum Pump