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KAHN INSTRUMENTS, INC.
885 Wells Road, Wethersfield, CT 06109
Tel: 860-529-8643; Fax: 860-529-1895
E-mail: [email protected]
www.kahn.com
The dewpoint sensing assembly comprises a measurement sample flow-through
housing, which contains optical signal emission and detection components. These
components are accurately positioned around a plated mirror, which is mounted on the
Peltier cooling device.
Sample gas is transmitted into the measurement chamber through stainless steel tubing
and fittings to ensure negligible contamination of the sample gas.
A high efficiency heat sink is mounted to the rear of the PTFE housing assembly. Forced
air cooling is provided within the unit to cool the sensor heatsink. Both the air inlet and
outlet vents are located on the rear panel of the unit, this allows the instrument to be
located in a rack unit above and below other instrumentation while maintaining the air
cooling flow required for continuous operation.
The sensor mirror is cooled by the Peltier cooling device to below the dewpoint
temperature until sufficient dew or ice forms on the mirror surface for the optical system
to detect. When this point is reached the electronic control circuit adjusts the Peltier
device power until the mirror temperature is controlled at the equilibrium value where the
rate of condensation equals the rate of evaporation - dewpoint.
2.4
Front Panel Controls
The following is a basic description of the function of each of the front panel user controls
and connections. For further information refer to the relevant section or Section 4.
a) GAS IN & GAS OUT
6 mm O.D. stainless steel tubing connections for the
sample gas inlet and outlet.
b) Flowmeter
Provides a visual indication of the sample flow. Note
that this will only operate when the unit is horizontal. All
other functions on the instrument will operate correctly
in any orientation.
c) Mains Power Switch
Isolates all power to the instrument, and includes a
visual indication (neon).
d) OPERATE/STANDBY
Refer to Section 2.6.
e) INITIATE Pushbutton
Manually starts a Balance cycle. Refer to Section 2.8.
f) ABC STATUS LED
Indicates current status of Balance cycle.
Refer to Section 2.7 and 2.8.
