Emerson Daniel Danalyzer 1000, Hardware Reference Manual

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SEP 2005
MODEL 1000
EQUIPMENT DESCRIPTION
2-4
2.1.5 Valving
A block valve should be installed immediately downstream of the sample takeoff point to permit
shutdown of the system for maintenance. Block valves should be either gate valves or cocks of the
proper material and packing, and should be rated for the process line pressure. Tight seating of all
connections is essential.
2.1.6 Calibration Gas
A calibration gas used for Process analysis should be blended to Primary Standards. Primary
Standards are blended using weights that are traceable to the National Bureau of Standards (NBS).
If the calibration standard is a gas, the standard should not have any component that could drop out
at the coldest temperature to which the gas will be subjected. A typical blend for a temperature of
zero degrees Fahrenheit (0°F) is listed in the following table. No dropout will occur in this
calibration gas if it is blended at a pressure below 250 psig.
Table 2-1. Contents of Example Calibration Gas
Gas Mole Percent
Nitrogen 2.5
Carbon dioxide 0.5
Methane Balance
Ethane 5.0
Propane 1.0
Isobutane 0.3
N-butane 0.3
Neopentane 0.1
Isopentane 0.1
N-pentane 0.1
N-hexane 0.03
If a liquid calibration standard is being used, the head pressure must be sufficient to prevent
bubble-out of components during hot weather.