Check the lubricant level
1. Regularly check the lubricant level while the vacuum pump is running and at operating tempera-
ture.
2. Make sure that the level is in the area at the center of the sight glass.
3. Check the lubricant fill level daily during continuous operation or whenever the vacuum pump is
switched on.
6.3 Adjusting sealing gas amount
NOTICE
Property damage from impermissibly high sealing gas pressure
Excessive sealing gas pressure leads to damage to the seals after switching on the vacuum pump.
► Make sure that the sealing gas pressure inside the pump does not exceed 1200 hPa.
► Stop the sealing gas supply immediately after switching off the vacuum pump.
Formula for calculating sealing gas flow:
Q
S
= (S
th
× p × A
S
)/p
0
● Q
S
= Sealing gas flow under standard conditions [Nm
3
/h]
● p = Intake pressure [hPa]
● p
0
= Ambient pressure under standard conditions [hPa]
● ∆p = Differential pressure max. [hPa]
● p
V
= Fore-vacuum pressure [hPa]
● A
S
= Sealing gas content at the operating gas flow (0.01 ≤ A
S
≤ 0.08)
● S
th
= Rated volume flow rate of the roots pump [m
3
/h]
Procedure
Depending on the operating pressure, the empirical value for the supplied sealing gas amount is be-
tween 1 % (for a high operating pressure) and 8 % (for a lower operating pressure) of the effective suc-
tion capacity. The set quantity of sealing gas influences effective pumping speed and achievable ulti-
mate pressure.
Inert gases, mostly nitrogen (N
2
), are used as sealing gas.
1. Open the sealing gas supply on the gas cylinder.
2. Set a max. pressure of 2500 hPa on the pressure reducer.
3. Set the desired quantity of sealing gas on the dosing valve of the flow meter.
Example for Okta 1000 G with, e.g., 50 hPa intake pressure and 8 % sealing gas content
Q
S
= (1284 × 50 × 0.08)/1013
Q
S
= 5.07 Nm
3
/h
At discharge pressures > 100 mbar:
Q
S
= (S
th
× (p
V
– ∆p) × A
S
)/p
0
6.4 Flushing suction chamber
NOTICE
Property damage from impermissibly high pressure build-up in the suction chamber
Exceeding the specified flushing quantities damages the vacuum pump.
► Observe the maximum permissible flushing quantities at max. 3000 hPa.
► Fully purge all supplied fluid.
► Observe the vapor compatibility of the downstream vacuum pumps.
Operation
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