01671H (DCN6051) 4-1
4 OPTIONAL HARDWARE AND SOFTWARE This section includes descriptions of the hardware and software options available for the
M701 instrument. For assistance with ordering these options please contact the sales
department of Teledyne API at:
TOLL-FREE: 800-324-5190
TEL: +1 858-657-9800
FAX: +1 858-657-9816
E-MAIL: apisales@teledyne.com
WEB SITE: http://www.teledyne-api.com/
4.1 CO Scrubber (OPT 1B)
The CO scrubber catalytically oxidizes CO to CO2. The catalyst is proprietary and
operates at room temperature; however, it is heated to approximately 70C to prevent
water condensation. It theoretically should never need changing. However, it may
become contaminated or poisoned over time so we recommend that it be replaced once
per year or sooner if the level of CO in the air is high.
4.2 Hydrocarbon Scrubber (OPT 2B)
The High Purity Hydrocarbon Scrubber (OPT 2B) includes the CO Scrubber (OPT 1B).
The optional Hydrocarbon scrubber catalytically converts hydrocarbons to carbon
dioxide and water. The scrubber consists of a cylindrical cartridge which contains a
preheat chamber and the pelletized precious-metal catalyst. The canister is heated by a
band heater with an integral type-K thermocouple and is housed in a stainless steel
casing with appropriate thermal insulation. The cartridge temperature is controlled by a
printed circuit assembly mounted on the outside of the scrubber casing. The controller
reads the thermocouple voltage, compensates for cold-junction temperature and
modulates the heater to maintain a constant cartridge temperature.
(Refer to Appendix A, P/N 00257)
The operating temperature of the cartridge is 300ºC. The temperature can be verified by
measuring the thermocouple voltage at TB1, the two terminal blocks at the top-left
corner of the board. Pin 1, the top terminal is the NEGATIVE. At 300ºC, the
thermocouple voltage is 11.2 mV in an ambient temperature of 25ºC (11.4 mV at 20º
and 11.0 mV at 30º). While the controller compensates for cold-junction temperature in
controlling the heater, the thermocouple voltage at the terminal block is not
compensated, so allowance must be made for ambient temperature when converting
the voltage to cartridge temperature. Pot R3, near the top right corner of the PCB,
controls the temperature set-point (turn Pot R3 clockwise to increase the setting). LED
DS1 blinks when the temperature is at the set-point. LED DS2 is an alarm and will be
ON if the thermocouple is OPEN. Pot R4 has no effect in this application.