A critical flow orifice is used to control the sample flow. The orifice is a precision-
drilled sapphire jewel protected by a 20 micron sintered filter. The critical flow orifice
never needs adjustment and maintains precise flow control as long as the ratio of the up-
stream to down-stream pressures is greater than .53 (sonic flow conditions).
1.6.6 Sample gas connection (see Figure 1.4)
A 2 m section of 1/4" O.D. PTFE tubing is needed to connect the sample source to the
Analyzer.
NOTE
USE PTFE, GLASS, STAINLESS STEEL OR
NON-REACTIVE MATERIALS FOR SAMPLE GAS
CONNECTIONS.
NOTE
USE VENT LINE WHEN SAMPLING FROM
PRESSURIZED MANIFOLDS - SAMPLE PRESSURE
SHOULD NOT EXCEED ±1" H
2
O
1.6.7 Zero/span valve connections (see Figure 1.4)
Zero air and span gas manifolds should supply their respective gases in excess of
800cc/min demand of the Analyzer. The manifold should be vented to the outside
atmosphere and be of sufficient length and diameter to prevent back diffusion and
pressure effects.
Adequate zero air can be supplied by the M300 using the IZS option or by using a
commercial calibrator.
P/N 02163G1 Teledyne API Model 300 CO Analyzer Instruction Manual - Page 12
