Instrument Description 3-9
Filters
The CPCs use three liquid filters. One liquid filter is used to filter butanol
supplied from the fill bottle while a second filters the butanol drain line. The
third is used to filter the condensed water and butanol mixture before it
passes through the Water Removal Pump.
Valves
Solenoid fill and drain valves enable butanol to be added or removed from
the liquid reservoir. The fill valve is actuated when the Auto-Fill is turned
ON and the level sensor indicates a low butanol level in the liquid reservoir.
When the butanol fill bottle is connected, butanol flows into the reservoir
until the level sensor indicates a full state. On the 3772, the drain valve is
activated through the front panel or through serial command. On the 3771,
the drain valve is activated through serial command. Butanol is drained
prior to shipment or removal of the saturator wick. See “User Settings” in
Chapter 4 and “Maintenance and Service” in Chapter 8.
Pressure Transducers
The Model 3772/3771 CPC uses three pressure transducers for monitoring
instrument flows. The differential pressure across the Critical Orifice is
measured to verify that a critical pressure is maintained across the orifice.
Differential pressure across the nozzle is measured and verifies the nozzle
in the optics block is free from obstruction. The ambient pressure is also
measured. These pressure transducers are mounted to the main PC
board. On the 3772, pressure information is viewable via the front panel
display. On both 3772 and 3771 CPCs, pressure information is available
through serial commands.
Electronics Boards
Four electronics boards identified in Figure 3-7, are used in
Model 3772/3771 CPC. The boards include main PC board, laser board,
detector board, and communication connector board. The 3772 also
includes a fifth board—flash memory board.
To Next Page
Loading...
