Teledyne 3000ZA-3X operating instructions By-Pass

Trace Oxygen Analyzer Maintenance

(including the cell) the pressure will be at atmospheric pressure (analyzer vented to atmospheric pressure). Note, all other pressure drops in the sample path are insignificant at these flow rates. This insures that the cell operates at atmospheric pressure. At very high flow rates (off scale of flow-meter), pressure drops other than the restriction device could become significant, and result in pressurizing the cell.

Example 2: A 3000TA is configured for vacuum service as follows. The unmarked restrictor is placed in the sample vent port. The downstream end of the restrictor is then connected to a vacuum pump and by-pass valve. The by-pass valve is adjusted to provide a flow rate of 1 SLPM. The sample pressure between the pump and the restrictor will be approximately -7 inches of mercury, while the pressure in the balance of the sample system including the cell will be approximately at atmospheric pressure (provided the sample flow into the analyzer is not blocked).

BY-PASS:

To improve the system response, a by-pass can be added to increase the sample flow rate to the analyzer by a factor of ten. A by-pass typically provides a sample flow path around the analyzer of 2 - 18 SCFH.

CALIBRATION GAS:

3000 series analyzer requirements for units with Auto-Cal options are as follows:

The customer must supply control valves (or restrictors) for any SPAN or ZERO gas source which is attached to the Auto-Cal ports. The valve should be adjusted to the same flow rate as the sample gas. When restrictors are used, the gas pressure must be adjusted to achieve the proper flow rate.

OPERATION WITHOUT A RESTRICTOR DEVICE:

Operation without a restrictor device is not recommend as mentioned above. A 3000TA without any flow restrictor device was tested on 11-19-97. This results in a flow rate of 2.4 SLPM @ 1 PSIG. This is a cv of 0.023 for the standard sample system.

REFERENCE: FLOW_1.XLS & FLOW_2.XLS for information on flow rates at various pressures.

Teledyne Analytical Instruments 59