Pumping Argon - Edwards GXS Series Instruction Manual

Refer to
the pump is running and warmed up, press and hold the start button (item 3) for 5
seconds. The pump green mode LED (item 10) will illuminate continuously. The pump
running LED (item 2) will flash.
To disable Green mode/standby mode, and therefore to enable the on‑process mode,
press and hold the start button (item 3) for 5 seconds. If the pump has warmed up, the
pump green mode LED (item 10) will go out and the pump running LED (item 2) will
illuminate continuously. If the pump has not warmed up, both the Green mode LED and
the pump running LED will flash until the pump is fully warm. The Green mode LED will
then go out and the running LED will illuminate continuously to indicate that the pump is
now on‑process.
Table 21 Green mode/standby sequence
Sequence
Green mode/Standby Inlet isolation valve is closed (if fitted).
The dry pumping system can also be set into Green mode/standby mode using the
following methods:
▪ PDT, by the commands menu. Refer to
▪ MCM MicroTIM. Refer to the MicroTIM manual D37360880.
▪ By commands sent over the serial interface using the SIM protocol. Refer to the
SIM Manual P41100200, or using the E54 protocol.

4.4 Pumping Argon

Due to its inert nature, Argon is commonly used in the heat treatment and other
metallurgical applications, especially at high temperatures. The thermodynamic
properties of Argon can give challenges and difficulties when it comes to the vacuum
pumping systems. The inherent thermal properties of Argon including its inefficiency to
transfer heat away to the cooling system which, if not controlled, can cause the
problems for dry vacuum pumps. If heat is not successfully removed from the rotors, a
differential thermal expansion can cause seizures.
The GXS160, GXS250 and GXS450 (with or without booster) can pump Argon with no
restrictions.
The GXS750, GXS750/2600 or GXS750/4200 is capable of pumping Argon but not
continuously at all pressures. At 110 Hz, the continuous operating range is restricted to
less than 20 mbar at the inlet to screw pump (this is equivalent to 10 mbar at the inlet to
booster). To extend the continuous operating range up to 500 mbar and to enable the
pump down of the large chambers, the operating speed of the pump must be reduced to
80 Hz. This is valid with Argon at ambient temperature.
M58800880_H - Operation
Figure: Front panel controls. To enable the Green mode/standby mode when
Description
Pump runs at standby (Green mode) speed.
Gas ballast valve is closed (medium‑duty pumps only).
If the pump temperature drops below working temperature
then it will start to warm up again.
Pump ready line will be off if pump is not warmed up.
Commands menu
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