General:

Volatility, expressed in terms of the 95 % evaporated temperature of the product, is a measure of the amount of least volatile components present in the product. Coupled with a vapor pressure limit, it serves to ensure essentially single-component products in the cases of commercial grades of propane and butane. When the volatility is coupled with a vapor pressure limit which has been related to density, as in the case of the commercial PB-mixtures, the combination serves to assure essentially two component mixtures for such fuels. When coupled with a proper vapor pressure limit, this measurement serves to assure that special-duty propane products will be composed chiefly of propane and propylene, and that propane will be the major constituent. The presence of hydrocarbon compounds less volatile than those of which the LPG is primarily composed is indicated by an increase in the 95 % evaporated temperature. When the type and concentralion of higher boiling components is required, chromatographic analysis should be used.

Cooling coil—Approximately 6 m of 4.8 mm is wound in an outside diameter of 54 mm. The top of the coil is  at least 25 mm below the top of the cooling vessel . The open ends of the coil shall are less than 100 mm. above as described per ASTM D1837. The downstream end of the coil is connected to a 3.2 mm. needle valve having an outlet connection not more than 76 mm long.

Test:

The sample is refrigerated by means of a cooling coil and collect 100 mL of liquid in a weathering tube, The sample allowed to evaporate ( “weather") at ambient pressure under specified conditions. When 5 mL of liquid test portion remains, the observed temperature is corrected for barometric pressure and thermometer ice point error, and reported as 95 % evaporation temperature.

Repeatability:    6°C(1.0°F)

Reproducibility: 1.0 (1.7°F) for butane and butane-propane mixtures

                        3°C(2.3°F)forpropane

This test method has no bias because the volatility is defined only in terms of this test method.

Differences between D1837 and D2158

Main Features:

• Holder to hold weathering tube in vertical position
• Wheels for easy transport
• Temperature range down to -85°C
• Level detection
• Stainless steel, robust bath
• Low energy consumption
• Easy to read display
• Very quiet
• High heat removal capacity

The TCC-B is available in the following voltages/frequencies:

• TCC-B D1837 230V/50Hz (P/N: 00T0315)
• TCC-B D1837 230V/60Hz (P/N: 00T0316)

See tab "More Information" for the specificationsheet and manual