Operation
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GA01423_002_C0 - 10/2016 - © Leybold
ZProceed as follows to start the pump:
1. Close the isolation valve to prevent drawback of debris from the vacuum
pump into vacuum chamber (open the purge gas valve if one is installed).
2. Switch the vacuum pump ON.
3. Open the isolation valve (close purge gas valve if one is installed) and
pump the vacuum chamber.
4.2 Pumping
Operating the pump continuously near its ultimate pressure (for example,
backing a turbomolecular pump) can cause deposits of foreign matter or
moisture in the pump resulting in failure.
Operate the pump with the purge gas valve open (see Sec. 4.3 “Purge Gas
Operation”), or close the isolation valve and open the purge gas valve for 3-5
seconds to atmosphere several times once a day to remove foreign matter
from inside the pump.
Operate at specified temperature
When pumping vapour, the inlet gas temperature must be Iess than 50 °C.
When vapour temperature is more than 50 °C, install a chiller or trap in the
piping between the vacuum chamber and the pump to reduce the inlet
vapour temperature to less than 50 °C. Pumping vapour of over 50 °C can
cause failure.
4.3 Purge Gas Operation (pumping of vapours)
When pumping vapour, open the purge gas port of the SCROLLVAC. If you
pump vapour with the purge gas valve port closed, condensed moisture
remains in the pump, resulting in failure.
Use care to avoid damaging the purge gas valve port (especially the silenc-
er).
When the purge gas valve is open, noise level increases and ultimate pres-
sure deteriorates slightly.
Purpose of the Purge Gas
The moisture volume drawn into pump varies depending on the temperature
and pressure in the vacuum chamber. Pumping humid gas can result in
moisture condensing in the pump. This remaining moisture can cause a dete-
rioration of the ultimate pressure or pump failure. When the vacuum chamber
contains gas with humidity of over 60 % RH, the pump must be operated
with the purge gas valve open. Operating the pump with the purge gas valve
open removes the moisture which allows the pump to reach its ultimate pres-
sure.
NOTICE
