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Izs permeation tubes (options 53 & 55), Table 5-2, Available permeation source options – Teledyne 9110EH - Nitrogen Oxides Analyzer User Manual

Page 53: Izs permeation tubes

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Model 9110EH Instruction Manual Optional Hardware and Software

In order to keep the permeation rate constant, the IZS enclosure is heated by a PID

(Proportional/Integral/Derivative) temperature control loop to a constant 50° C (10° above
the maximum operating temperature of the instrument). A thermistor measures the actual

temperature and reports it to the CPU for control feedback. The flow rate across the IZS
oven is controlled with a critical flow orifice to 60±5 cm³/min.

Please note, that the IZS option does not contain the actual permeation tube, which needs
to be ordered separately. See next option for description.

CAUTION

Gas flow must be maintained at all times for units with a permeation tube

installed. Insufficient gas flow allows NO

2

gas to build up to levels that will

severely contaminate the instrument.

Figure 3-12 shows the internal pneumatic connections for a Model 9110EH with IZS option
installed. Table 5-1 shows the operational state of the valves associated with the IZS option
during the analyzer’s various operational modes. SPAN gas on the zero/span valve option is

equivalent with the permeation tube NO

2

gas stream on the IZS option.

The state of the IZS valves can also be controlled:

• Manually from the analyzer’s front panel by using the SIGNAL I/O controls located

under the DIAG Menu (Section 6.8.1),

• By activating the instrument’s CAL or AutoCal features (Section 7.8),
• Remotely by using the external digital control inputs (Section 6.9), or
• Remotely through the RS-232/485 serial I/O ports (Section 6.9.10).

5.6.3. IZS Permeation Tubes

One IZS permeation tube is necessary to operate the IZS option. Two different

NO

2

permeation tubes are available, they are identical in size and shape but are designed to

have different permeation rates.

Table 5-2: Available Permeation Source Options

Permeation Rate

(± 25%)

Approximate NO

2

Concentration

421 ng/min 300 - 500 ppb

842 ng/min 600 - 1000 ppb

Each tube is shipped with a calibration certificate, traceable to a NIST standard, specifying
its actual NO

2

permeation rate to within ±5%. The calibration is performed at a tube

temperature of 50°C and a flow rate of 0.56 liters per minute.

M9110EH

Rev 0 39