Maintenance And Inspection; General; Periodical Inspection - Rietschle TWISTER VSB 120 Manual De Instrucciones

5. Maintenance and Inspection

5.1 General

• During operation, the temperature will rise corresponding to the compression ratio due to compression heat. However, if
localised temperature hot spots occur or the paintwork is scorched, this is abnormal. It may be because of the interference
of rotor with casing, or the pump has sucked in some foreign material. Therefore, stop the pump immediately to check the
condition. In some case, the rotors and the casings might have corroded after a long service life, which will make the
clearance between these parts larger and result in high rates of pumped gas re-cycling, with the result that the temperature
rise becomes higher than it was initially. In such cases, the pumping speed will be reduced. Stop the pump and take
measurements of the clearances for consideration of corrective action.
• Abnormalities can be noted by making routine checks on bearing temperature, vibration or noise. Therefore, daily inspec-
tion is advised.
• Interference between rotors or between rotor and casing can be noted by listening to sound through a stethoscope applied
against the casing.
• In winter, in cold regions, whenever the pump is stopped, cooling water should be drained. Freezing of water could damage
the jacket.

5.2 Periodical Inspection

a.) Daily
• Oil-Level Gauge: Excess or lack of lubricant can damage gears and bearings.
• Check that the amount of cooling water is adequate.
• Check the temperatures of Grease cover and Front end Cover. Use of a suitable thermometer or a surface thermometer may
be convenient.
• Check the suction and discharge pressures. To check these pressures, make sure that the operation of the pump is within
planned specifications.
• Check the load on the motor. Note that an increase in the motor load indicates some kind of abnormality.
b.) Monthly
• Check tension of V-belt.
• Check lubricant colour (If, Oil colour is discoloured, replace lubricant).
• Check oil level. If oil consumption is high with no apparent leaks, check mech. seal.
c.) Every 6 month
• Check pipe connections.
• Check oil & grease and change them when need.
d.) Yearly
• Check mech. seals, lip seals & oil seal.
• Check inner surface of rotors and casings. Disassemble the piping on suction side to check the inner surface of rotors and
casings.
• Check the gear. - Remove the front end cover to check the gear.
• Replace lubricant in the front end cover.
No. Item
1 Ampere of motor
2 Rotation
3 Suction and discharge pressure
4 Noise and Vibration
5 Temperature
6 Oil amount of front end cover
7 Water contamination of front end cover Clean or not?
8 Oil leak
9 Lubricant replacement
Amount and pressure of cooling water
10
for pump casing & silencer (separator)
11 Suction and discharge pipe
12 Cleaning and dry run at stop
13 Check inside of casing and rotor
Mech. seal, lip seal, bearing, o-ring,
14
packing V-belt / coupling
Screw vacuum pump maintenance and check list
Any change? Ampere as specified?
Is rotation smooth and correct
Are those pressure as specified
Any abnormal sound or vibration
Any ecessive oil temperature rise on bearing and other parts
Is oil at proper level?
Oil not leaked?
All oil & grease in front end cover & grease cover to be replaced
Is the amount as specified?
Is there any scale?
Close the main V/V on suction side, and run for 20 ~ 30 min.
while purging N
2
Any rust or flaw found?
Replace when need
- 7 -
Check point
or air
a.) b.) c.) d.)
•
•
•
•
•
•
•
•
•
•
•
•
•