Cooling Fans - Thermo Scientific LTQ Series Hardware Manual

2
Functional Description
Mass Spectrometer
Damping Gas Inlet Assembly
Sheath Gas, Auxiliary Gas, and Sweep Gas Valves

Cooling Fans

32 LTQ Series Hardware Manual
The damping gas inlet assembly controls the flow of helium into the mass analyzer cavity.
Helium (275 ±70 kPa [40 ±10 psi], 99.999% ultra high purity) enters the mass
spectrometer through a 1/8 in. port on the back of the mass spectrometer. The mass
spectrometer regulates the flow of helium and delivers it to the mass analyzer.
Helium in the mass analyzer cavity dampens ionic motion and improves the performance
of the mass spectrometer. See
The sheath gas, auxiliary gas, and sweep gas valves control the flow of nitrogen into the
API source (Figure 22
probe that sprays (nebulizes) the sample solution into a fine mist as it exits the sample
tube. Auxiliary gas is the outer coaxial nitrogen gas that assists the sheath gas in the
nebulizing and evaporating sample solutions. Sweep gas flows out from behind the sweep
cone in the ion source interface. Sweep gas aids in solvent declustering and adduct
reduction.
Dry nitrogen (689 ±138 kPa [100 ±20 psi], 99% high purity) enters the mass
spectrometer through a 1/4 in. port on the back of the mass spectrometer. The data
system controls the valves that regulate the nitrogen pressure. You can set the flow rates
from the Tune Plus window.
Five fans provide cooling for the mass spectrometer. One 2.8 CMM (100 CFM) fan cools the
rf voltage coil. One 0.59 CMM (21 CFM) fan cools the turbomolecular pump. Three
2.8 CMM (100 CFM) fans cool the electronics in the tower. The back of the mass
spectrometer draws air in. The exhaust air exits from the vent slots on the sides of the mass
spectrometer.
CAUTION To ensure safety and proper cooling, always operate the mass spectrometer with
its covers in place. This is also necessary to comply with product safety and
electromagnetic interference regulations.
"Helium Damping Gas"
on page 28). Sheath gas is the inner coaxial nitrogen gas of the API
on page 25.
Thermo Scientific