6.3 Switching on the vacuum pump
WARNING
Danger of poisoning due to toxic process media escaping from the exhaust pipe
During operation with no exhaust line, the vacuum pump allows exhaust gases and vapors to escape
freely into the air. There is a risk of injury and fatality due to poisoning in processes with toxic process
media.
► Observe the pertinent regulations for handling toxic process media.
► Safely purge toxic process media via an exhaust line.
► Use appropriate filter equipment to separate toxic process media.
CAUTION
Danger of burns on hot surfaces
Depending on the operating and ambient conditions, the surface temperature of the vacuum pump
can increase to above 70 °C.
► Provide suitable touch protection.
Information for roots pumps with overflow valve
● You can activate a roots pump with overflow valve simultaneously with the backing pump.
● The overflow valve is open at the beginning of evacuation in high pressures ranges. This protects
the Roots pump from overload. The overflow valve closes as soon as the differential pressure be-
tween the suction side and pressure side falls below 20 hPa.
Information regarding roots pumps with blocked overflow valve
● You may only activate a roots pump with blocked overflow valve in the event of cut-in pressure if
the backing pump can assume the required amount of gas.
● Depending on the pumping speed of the backing pump (S
Vvp
), the cut-in pressure for the roots
pump is calculated with (p
Vv
) = 70 hPa/(1 – S
Vvp
/S
Okta
).
Example:
● Okta ATEX with pumping speed S
Okta
= 2155 m
3
/h at 50 Hz
● Backing pump with pumping speed S
VvP
= 250 m
3
/h at 50 Hz
● Cut-in pressure p
Vv
= 70 hPa/(1 – 250 [m
3
/h]/2155 [m
3
/h]) =
79.2 hPa
Impermissible continuous operation
Continuous operation of the roots pump with this pressure differential is not permissible as
the maximum gas temperature will be exceeded in the exhaust channel!
Procedure
1. Switch the vacuum pump on.
2. Allow the vacuum pump to warm up for approx. 30 minutes prior to process start with the vacuum
flange closed.
3. Check the lubricant level with the vacuum pump running and at operating temperature.
– The fill level must be within the marks on the sight glass during operation.
4. Check the fill level daily during continuous operation, and every time the vacuum pump is switch-
ed on.
6.4 Adjusting the sealing gas amount
WARNING
Risk of injury from reactive, explosive or other hazardous gas/air mixtures
Uncontrolled gas inlet of air or gases containing oxygen promotes formation of unexpected explosive
gas/air mixtures in the vacuum system. This results in severe injuries.
► Use only inert gases for supplying the sealing gas supply in order to avoid a potential ignition.
Operation
34/60
