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Pirani Gauge
Vent Valve
Inlet Gas Hardware
Thermo Scientific
CAUTION Always plug the forepump power cord into the outlet labeled PUMP OUT on
the rear panel of the Surveyor MSQ Plus MS detector. Never plug it into a wall outlet.
Failure to follow these instructions could lead to instrument damage and personal injury.
A Pirani gauge measures the pressure in the analyzer region of the vacuum manifold.
The vent valve allows the vacuum manifold to be vented to air that has been filtered through a
metal mesh. The vent valve is a solenoid-operated valve. The vent valve is closed when the
solenoid is energized.
Nitrogen gas is used as both the nebulizing gas and the sheath gas for the API probe. Nitrogen
gas is also used to pressurize the reference inlet reservoir that contains the calibration solution
for the MS detector. Dry nitrogen [nominally set to 520 kPa (75 psi) or 450 kPa (45 psi),
99% purity] enters the Surveyor MSQ Plus MS detector through a 6 mm port labeled
GAS IN located on the rear panel of the MS detector. See
hardware then controls the flow of nitrogen gas to the API probes and the reference inlet
reservoir.
As
Figure 22
shows, the inlet gas hardware consists of two regulators, three solenoid valves,
and two restrictors.
Figure 22. Functional block diagram of the inlet gases hardware
Vent to
atmosphere
2
3
2
Reference
inlet reservoir
1
1
1
N
GAS IN
2
2
Functional Description
Figure 13
on
page
22. The inlet gas
Sheath
2
gas
API probe
Nebulizing
gas
Restrictor
On/Off
solenoid valve
Regulator
Surveyor MSQ Plus Hardware Manual
MS Detector
33
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