Teledyne 9110EH - Nitrogen Oxides Analyzer - Manual (Page 170)

Instrument Maintenance Model 9110EH Instruction Manual
• Disconnect the black 1/4" exhaust tube and the 1/8” sample and ozone air tubes
from the reaction cell. Disconnect the heater/thermistor cable.
• Remove four screws holding the reaction cell to the PMT housing and lift the cell and
manifold out as shown in the inset of Figure 9-6.
Figure 9-6: Reaction Cell Assembly
• The reaction cell will separate into two halves, the stainless steel manifold assembly
and the black plastic reaction cell with window, stainless steel cylinder and O-rings.
• The reaction cell (both plastic part and stainless steel cylinder) and optical glass
filter should be cleaned with methanol and a clean tissue and dried thereafter.
• Usually it is not necessary to clean the sample and ozone flow orifices since they are
protected by sintered filters. If tests show that cleaning is necessary, refer to
Section 9.3.10 on how to clean the critical flow orifice.
• Do not remove the sample and ozone nozzles. They are Teflon threaded and require
a special tool for reassembly. If necessary, the manifold with nozzles attached can
be cleaned in an ultrasonic bath.
• Reassemble in proper order and re-attach the reaction cell to the sensor housing.
Reconnect pneumatics and heater connections, then re-attach the pneumatic sensor
assembly and the cleaning procedure is complete.
• After cleaning the reaction cell, it is also recommended to exchange the ozone
supply air filter chemical as described in Section 9.3.3.
• After cleaning, the analyzer span response may drop 10 - 15% in the first 10 days
as the reaction cell window conditions. This is normal and does not require another
cleaning.
156 M9110EH Rev 0