Edwards STP-iXL455

STP-iX455/iXL455 Series Instruction Manual
4-17
Installation
4.3.5 Vacuum Piping
◇ DO NOT open the STP pump through the flange to atmospheric air while the STP
pump is running.
If atmospheric air flows into the STP pump, it may not function normally.
◇ Depending upon the type of the backing-pump used, atmospheric air may reverse
flow into the STP pump when the backing-pump stops.
Attach a vacuum valve to the middle of the piping between the STP pump outlet
port flange and the backing-pump, and close the vacuum valve when the
backing-pump stops.
In order to let the STP pump bring its performance into full play, follow the precautions
below:
1) Be careful not to scratch the flange of the STP pump.
Before installing the STP pump, check whether or not there are scratches on the
surface.
2) Use stainless steel or aluminum alloy tubes with a low out gassing loss to connect
the vacuum equipment to the STP pump.
3) Take measures for minimizing leakage. It is also necessary to degrease the tubes as
regularly as possible to keep the gas loss as low as possible.
4) It is recommended to use a backing-pump of pumping speed 240 L/min or more.
However, the pressure at the inlet and outlet ports varies with the flow rate of gas,
capacity of the vacuum equipment, length and material of the piping.
Select a backing-pump in accordance with the capacity and starting method
(simultaneous starting, starting after generating roughing vacuum) suitable for the
vacuum equipment you use.
5) Connect the STP pump and the backing-pump using stainless steel or aluminum
alloy tubing, flexible tubing, vacuum rubber or Teflon tubing, and other.
The following measures can be used to avoid the transmission of the vibration of the
backing-pump to the STP pump and the vacuum equipment.
DO NOT place the backing-pump on the same floor as the vacuum equipment.
Locate the backing-pump on a vibration-proof table.
Attain 1/3 or less of the rotational speed of the backing-pump, when adjusting
the inherent frequency of the backing-pump installed on a vibration-proof table.
Attach a weight to the piping from the backing-pump, or secure the piping to a
rigid, heavy object free of vibration.
Use a tube of high flexibility.
6) Depending upon the type of the backing-pump used, oil vapor may contaminate the
inside of the STP pump. Some oil viscosity could cause a malfunction when there is a
strong reverse flow of oil.
Take the following measures to ensure the correct flow of oil:
Attach a vacuum valve to the middle of the piping between the STP pump outlet
port flange and the backing-pump.
Attach an absorption trap adjacent to the vacuum valve.
◇ Abnormal noise or excessive vibration failure (Disturbance) caused by rotor incline
toward outlet port may be generated when performing roughing vacuum
depending upon pumping speed of the backing-pump, chamber capacity, or piping
length. When the failure is detected, perform the RESET operation.