The L5-65 centrifuge is located in room W357 in building 95 and is for general departmental use. Use the instrument log book to log in and out. The following is a brief summary of the operating procedure:
Precooling the Instrument
1. Turn on the cooling water and then the main power switch.
2. Check the oil level.
3. Close the chamber door.
4. Turn on the vacuum pump.
5. Turn the TEMP LIMIT knob all the way clockwise and then turn the TEMP SET knob to the temperature desired for the run.
6. After the chamber has had time to reach the desired temperature and dry out the roughing vacuum pump will have warmed up (about 30 minutes) you are ready to begin. Turn OFF the vacuum pump and REFRIG.
Fixed-Angle and Swinging-Bucket Runs
1. Open the chamber door.
2. Wipe off any condensate on the rotor
3. Place the rotor on the drive shaft
4. Close the chamber door.
5. Turn ON the VACUUM pump.
6. Turn ON the BRAKE
7. Set the ACCELERATION RATE dial
8. Turn ON REFRIG
9. Turn ON the DIFFUSION PUMP
10. After the vacuum gauge pointer has left the black ATM area, set the timer. For runs less than 30 minutes, turn the dial past 30 and back to the desired time. Or runs longer than 5 hours, set the dial to HOLD.
11. Set the speed selector dial.
12. Make sure the WATER, OIL, REFRIG, DIFFUSION PUMP, and VACUUM lights are all on and that the vacuum is pulling down before starting the drive.
13. Start the rotor by pressing the START button, holding it until RUN (it does not work) and SPEED NORMAL lights come on.
14. After rotor temperature has reached the set point, set the temperature limit.
Ending the Run
Caution: To stop the run for any reason turn the timer dial to 0 from either direction. Do NOT proceed with the following steps until the rotor has come to a full stop. Allow 5 minutes for the diffusion pump to cool before turning off the roughing pump. Normally the stop time for the rotor will be over 5 minutes.
1. Turn OFF the REFRIG
2. Turn OFF the vacuum pump
3. Wait for the chamber pressure to return to atmospheric (about 1 minute).
4. Open the chamber door and remove the rotor. Pull the rotor steadily up without jerking.
If no more runs are to follow:
5. Close the chamber door.
6. Turn the vacuum pump ON again for about 10 minutes while the chamber warms up. This will prevent condensation in the chamber.
7. Turn the VACUUM pump OFF and wait a minute or two for pressure to equalize. Never leave a vacuum in the chamber.
8 Turn off the main power circuit breakers
9. Turn off the water.
In Case of Power Failure During the Run
If the facility power fails only momentarily controls may be left on to continue the run. If an instrument circuit breaker has tripped, try resetting the level to restore power.
If power can not be restored immediately, cancel the run by turning the timer dial to 0. (If the timer is left on and the rotor is still turning, the rotor will go to the set speed when power is restored.) The brake will be inoperative.
With power off, the tachometer will register zero, not the actual rotor speed, so the operator must listen for a full stop. When the rotor has stopped, turn OFF the REFRIG, VACUUM, and POWER switches, and vent the chamber. To vent the chamber, remove the front panel Turn the projecting screw on the manual vacuum release valve to admit air to the rotor chamber. Wait 1 minute for air to return and open the chamber door, then close the valve.
Some Quick Helpful Hints
1. If everything has been done correctly and the unit still does not run there are four common area to check:
2. Any flashing light indicates disfunction.
3. A flashing SPEED NORMAL light means the speed setting is too high for the rating recommended on the rotor in the chamber.
4. De certain the "wobble light" next to the rotor spindle is on before you place the rotor in the chamber. If it is not on, push the reset button.
5. The START Run light and Speed Normal light must be on simultaneously for lock-in mode.
6. Leave the ACCELERATION RATE control on 2 routinely. If you desire to accelerate a heavy rotor rapidly, set on 7. For light rotors and gradients, use at 2 setting.
8. Follow Ending the Run instructions to remove condensation from the chamber at the end of a run.
