Edwards nEXT730 - Vent Gas Specification and Vent Control Data; Materials Exposed to Gases Pumped; Figure 8 Maximum Allowed Rate of Pressure Rise During Venting: Pressure against Time

B8J200880_E - Technical data
Page 34
The pump can be used to pump oxygen and water vapour, subject to the following
conditions:
▪ Oxygen - The oxygen concentration must be less than 25% by volume.
4.4 Vent gas specification and vent control data
Although the pump may be vented to atmosphere, high relative humidity of the air may
greatly increase the subsequent pump‑down time. To reduce pump‑down times vent
with dry, clean gases. Refer to Vent options, vent valve connection and control on page
90 for a description of the vent options and the vent valve connection and refer to
Controlled venting options on page 83 for configuring the venting options.
Table 7 Vent gas specification and vent control
Vent gas specification and control
Reference data
Vent gas
Dry air, nitrogen, argon or other inert
gases
Maximum dew point at atmospheric
pressure
-22 °C
Maximum size of particulates
1 µm
Maximum concentration of oil
0.1 parts per million
Recommended time for rotational speed
to reach 50%
> 15 seconds
Maximum allowed rate of pressure rise
Refer to figure below
Maximum allowable vent gas supply
pressure
1 bar (gauge), 14.5 psig, 2 x 10
5
Pa
Figure 8 Maximum allowed rate of pressure rise during venting: pressure against time
1000
100
10
1
0 50 100 150 200 250 300
s
4.5 Materials exposed to gases pumped
The following materials and component types are exposed to the gases pumped:
▪ Steel and aluminium alloys
▪ Fluoroelastomer and O‑rings
▪ Hydrocarbon lubricant
▪ CFP
▪ Rare earth magnets
▪ Silicon nitride
mbar
BC-0036-A