MRK-D-0048 V4
Aeroqual Dust Sentry / AQS User Guide
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Figure 12-2 Direct and Zero switching gas module design
The gas flow rate is controlled using a critical orifice shown in red in Figure 12-2. The flow rate is listed in
Table 12-1.
Each gas module contains: a gas inlet port (white ring),a gas exhaust port (blue ring), two 12 V power
connectors to allow the module to be connected to a 12 V power bus, two RJ-45 connections to allow the
module to be connected to the RS-485 communications bus, and a module status LED.
Gas flow through modules
The gas flow through all of the gas modules is powered by a single diaphragm pump inside the monitor
enclosure. The pump pulls sample air through the gas module.
After
it has been measured the sample air
passes through the pump and is exhausted outside the monitor.
There are two different types of tubing material used to handle the gas flow.
Before the gas reaches the sensor, all of the tubing material is rigid non-reactive PFA.
After the sample has passed the sensor all of the tubing is flexible R3603 Tygon
The vacuum side of the pump is to the gas outlet (exhaust) of each module with
Tygon
tubing. This is
illustrated in Figure 12-3.
Figure 12-3 A single pump is used for all gas modules. The vacuum port of the pump is connected to the outlet of
each gas module
Direct design:
Ozone
Zero switching design:
NO
2
,
VOC