Teledyne 3000TA-XL-EU, Trace Oxygen Analyzer operating instructions 3000XL Series Analyzers

Trace Oxygen Analyzer Appendix

A-5	3000XL SERIES ANALYZERS
	APPLICATION NOTES ON
	PRESSURES AND FLOW RECOMMENDATIONS

3000 series analyzers require reasonably regulated sample pressures. Whilethe3000analyzersarenotsensitivetovariationsofincomingpressure (provided they are properly vented to atmospheric pressure) The pressure must be maintained as to provide a useable flow rate trough the analyzer. Any line attached to sample vent should be 1/4 or larger in diameter.

FLOW RATE RECOMMENDATIONS:

A usable flow rate for a 3000XL series analyzer is one which can be measured on the flowmeter. This is basically 0.5 - 2.0 SLPM . The optimum flow rate is 1 SLPM (mid scale). Note: response time is dependent on flow rate, a low flow rate will result in slow response to O2 changes in the sample stream. The span flow rate should be the approximately same as the sample flow rate.

CELL PRESSURE CONCERNS:

The sensors used in 3000XL series analyzers are optimized to function at atmospheric pressure. At pressures other than atmospheric the diffusion rate ofO2willbedifferentthanoptimumvalue.Higherpressureswillproducefaster O2 diffusion rates resulting in higher O2 reading and shorter cell life. To use a 3000XL series analyzer at a cell pressure other than atmospheric, the analyzer must be calibrated with a known calibration gas at the new cell pressure to adjust for the different diffusion rate. Cell pressures below 2/3 atmospheric are not recommended because they tend to cause excessive internal expansion whichmayresultinsealfailure.

For operation at cell pressures other than atmospheric care must be taken not to change the sample pressure rapidly or cell damage may occur. For cell pressures above atmospheric, caution must be exercised to avoid over pressuringthecellholder.

FLOWCONTROLVALVE:

All 3000XL series analyzers have a flow control device. This device is a needle valve, and serves two functions in the sample path. The first function is to limit the flow rate of the sample through the analyzer. The needle valve is chosen to operate over a specific range of pressures and provide a useable flow rate over that range.

The second function that the needle valve provides is a pressure drop. This device is selected to provide the only significant pressure drop in the samplepath.

Teledyne Analytical Instruments A-5