Turbo Pump And Fan - Agilent Technologies 5975C TAD VL MSD Troubleshooting And Maintenance Manual

Turbo Pump and Fan

The turbo pump is clamped directly to the bottom of the analyzer chamber.
The turbo pump has a cylindrical body with its inlet open to the interior of the
analyzer chamber. Inside the pump body is a central shaft or cylinder. Sets of
small blades (airfoils) radiate from the central shaft. The shaft spins at up to
60,000 revolutions per minute (rpm) in the performance turbo pump, and
90,000 rpm in the standard turbo pump.
Turbo pumps move gas by momentum transfer. The turbine blades are angled
so that when they strike a gas molecule it is deflected downward. Each set of
blades pushes the gas molecules further down toward the pump outlet.
The foreline pump is connected by a hose to the outlet of the turbo pump.
It removes the gas molecules that reach the outlet.
A controller regulates current to the pump and monitors pump motor speed
and temperature. A cooling fan is located between the turbo pump and the
front panel of the MSD. The fan draws air from outside the MSD and blows it
over the pump.
The turbo pump turns on automatically when the MSD power is switched on.
The system allows the analyzer to be turned on when the turbo pump is
greater than 80% speed, but the pump normally operates at 100% speed. Turbo
pump MSDs typically maintain an indicated pressure below 8 × 10
helium column flows up to 4 mL/minute for the performance turbo pump, and
up to 2 mL/minute for the standard turbo pump. Pressure (vacuum) can only
be measured if your MSD is equipped with the optional gauge controller.
The turbo pump spins up (starts) and spins down (stops) quickly. This
simplifies pumpdown and venting. From initial power-on, the system can
pump down to operating pressure in 5 to 10 minutes.
See Also
• To pump down the MSD
• To vent the MSD
• Turbo pump control,
5975 Series MSD Troubleshooting and Maintenance Manual
page 221.
6
Vacuum System
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Torr for
191