Teledyne Model 300EU Pneumatic Operation, The A-Ref Carbon Monoxide Scrubber, M300EU, 05831 Rev

THEORY OF OPERATION	M300EU
	Addendum to M300E/EM Manual P/N 04288

The auto-reference measurement takes approximately 15 minutes. To ensure that the sample chamber of the optical bench is properly purged when switching between the sample and auto-reference measurements and vice-versa, each auto-reference cycle includes a 3 minute dwell period before and after the actual measurements are made. This cycle is restarted every 4 hours by an ACAL sequence, programmed at the factory (see Section 6.4).

Figure 10-2: Auto-Reference Measurement Cycle

10.2. PNEUMATIC OPERATION

With the exceptions to the difference discussed on other portions of this addendum regarding the A-REFCO scrubber and the Nafion→ dryer, (See Sections 3.2, 5.1.1, 5.1.2, 5.1.3, 10.1.1 & 0) the pneumatic operation is the same as that described in Section 10.3 of the M300E/EM Operators Manual (P/N 04288).

10.2.1. THE A-REF CARBON MONOXIDE SCRUBBER

A special CO scrubber is used to remove all of the CO from the gas stream when the instrument is performing an auto-reference measurement. The scrubber contains a substance that catalyses a chemical reaction converting any CO in the gas stream to CO2.

NOTE

To operate properly, the gas flowing though the scrubber must contain at least 5% O2.

This includes calibration gases such as zero air and span gas.

The O3 scrubber is located inside the auto-reference valve assembly.

50 05831 Rev. 01