BOC E2M28, Instruction Manual

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E2M28 and E2M30 Rotary Vacuum Pumps
OP
ERATION
PAGE
25
Issue K 25 Jul 05
4.3 Start-up
If the oil is contaminated, or if the pump temperature is below 13
o
C, or if the electrical supply voltage
is more than 10% below the lowest voltage specified for the pump, the pump may operate at a reduced
speed for a few minutes. On single-phase pumps, if the pump continues to operate at reduced speed, the
motor thermal overload device will open and stop the pump. When the motor has cooled, the thermal
overload device will reset automatically and the pump will restart.
1. Check that the pump oil-level is between the MAX and MIN marks on the bezel of the oil-level
sight-glass; if it is not, refer to Section 5.3.
2. Turn the gas-ballast control to the required position (refer to Section 4.2).
3. Switch on the electrical supply to the pump.
4. Check that the oil-level in the sight-glass drops slightly (by 3 to 5 mm) after start-up. This shows
that the pump has primed with oil.
5. If the pump fails to prime, operate the pump with the inlet open to atmosphere for approximately
30 seconds. Then isolate the inlet and check that the oil-level drops by 3 to 5 mm.
6. If you want to achieve ultimate vacuum, to pump condensable vapours or to decontaminate the
pump oil, refer to the procedures in Sections 4.4, 4.5 and 4.6 respectively. Otherwise, open the
vacuum system isolation-valve.
4.4 To achieve ultimate vacuum
If the pump does not achieve the performance specified in Section 2.2, make sure that this is not due to
your system design before you contact your supplier or BOC Edwards for advice, In particular, the
vapour pressure of all materials used in your vacuum system (including pump oil, see below) must be
much lower than the specified ultimate vacuum of the pump.
Refer to Section 5.11.3 for a list of possible causes for failure to achieve the specified performance; note
however that the most common causes are:
• Your pressure measurement technique or gauge head is unsuitable or the gauge head is faulty.
• You have used an oil other than the recommended oil, and the vapour pressure of the oil is higher
than the specified ultimate vacuum of the pump.
Use the following procedure to achieve ultimate vacuum:
1. Isolate the pump from your vacuum system.
2. Turn the gas-ballast control fully anti-clockwise (fully open) and operate the pump for at least
1 hour (or overnight) to thoroughly purge the oil of contaminants.
3. Close the gas-ballast control.
4. Open the vacuum system isolation-valve and pump down to ultimate vacuum.
WARNING
Do not block the pump outlet or allow the outlet pressure to rise above 1.5 bar absolute.
If you do, the oil box may fracture and may cause injury to people nearby.