Sample System Design; Pressure And Flowrate Regulation - Teledyne 2000A-EU Operating Instructions Manual

Thermal conductivity analyzer

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Table of Contents

Thermal Conductivity Analyzer

3.4.1

Gas Connector and Control Panels for specific applications are avail-

able as extra cost additions. These panels are usually designed around a

standard manifold that attaches to the Model 2000A series analyzer below

the front panel.

For those customers wishing to incorporate their own sample system,

electronic input/output ports are provided on the rear panel for the opera-

tion of solenoid valves under the complete control of the Model 2000A

electronics. See section 3.3. The recommended system piping schematic is

included among the drawings at the rear of the manual.

The unit is manufactured with

ports. The customer must provide matching fittings.

For best results, use the recommended piping system. Select a

flowmeter that can resolve 40-50 cc/min (0.08 scfh) for the reference path

of the analyzer, and select a flowmeter that can resolve 150 cc/min (0.3

scfh) for the sample path of the analyzer.

Note: The sample-line pressure regulator should be installed as

close to the sample point as possible to minimize sample-line

lag time.

3.4.2 Pressure and Flowrate Regulation

Appropriate pressure reducing regulators must be installed at all gas

supply sources. To minimize flowrate adjustments the pressure regulators

on the supporting gas supply cylinders should be adjusted to provide the

same output pressure as the sample line regulator.

The gas pressure input should be reasonably well regulated. Pressures

between .35 and 3.5 bar (5 - 51 psig) are acceptable- .7 bar (10 psig) is

normal as long as the pressure, once established, will keep the flow

constant during analysis, and within 50-200 cc/min (between 0.1 and 0.4

scfh). See Note.

Note: Gases lighter than air have a flowrate higher than indicated

on the flowmeter, while gases heavier than air have a flowrate

lower than indicated. Values can range from one half to twice

the indicated flowrate.

For example: For hydrogen or helium, set the flowrate to 50

cc/min (0.1 scfh). For carbon dioxide or argon, set the flow-

rate to 200 cc/min (0.4 scfh).