ThermoFisher Scientific 146iQ, Instruction Manual

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Introduction
Principle of Operation
Thermo Scientific 146iQ Instruction Manual 1-5
be flushed. The 146iQ calculates the ozone concentration from the ratio of
zero and sample gas intensities and outputs the concentration to the front
panel display, the analog outputs, and also makes the data available over the
serial or Ethernet connection.
The 146iQ can also be used as a permeation gas source when equipped
with an optional permeation tube oven, as shown in
Figure 1–5 . Accuracy
is achieved since both the release rate of the permeation tube gas and the
flow of zero air through the zero-air mass flow controller are known, and
the temperature of the permeation tube is stable. Temperature stability of
the permeation tube is accomplished by allowing only a small amount of
zero air to enter the permeation tube oven to be heated. The major portion
of zero air bypasses the oven and is routed to the mixing chamber. The
solenoids on either side of the permeation tube oven, under microprocessor
control, are used to route the flow of gas going through the oven to either
the main air stream or to exhaust. It should be noted that zero air must
always flow through the permeation tube oven, regardless of the 146iQ
output flow, so the oven may be kept at a stable temperature. To
accomplish this, a flow of zero air set by a capillary at approximately 150 cc
per minute is continuously fed through the permeation tube oven.
When the permeation oven is activated, up to six permeation dilution gas
levels (ppm) can be set, in conjunction with the gas dilution system that
controls the flow rate of zero air.
Figure 1–6 shows the hardware/plumbing configuration with both the
optional ozone generator and permeation oven installed.
Permeation Oven