Simple Ships Centrifuge Operation Explained

We have discussed principle principle of operation of purifiers. Lets learn how to start and stop purifiers, contributing to necessary safety measures before starting, de-sludging procedures, and emergency stopping.
We all know that centrifuges are a crucial type of auxiliary equipment up to speed ships and that they are classified into two operating functions. One is often a clarifier, which separates solids from liquids. The other type is often a purifier, which separates liquids of density. The Purifier is run on the principle of separation by centrifugal force. But in order to optimize the purification process, certain parameters should be adjusted before the purifier is started. Out of those parameters, very important parameters are:

1. Feed inlet oil temperature: Before entering the purifier, the dirty oil passes with the heater. This raises the temperature, thus lowering the viscosity of the oil to be purified. The lower the viscosity, the higher will be the purification.
2. Density of Oil: As the dirty oil entering the purifier is heated to lessen the viscosity, the density also reduces. The lower the density, better the separation.
3. R.P.M of the rotating bowl: If the purifier has not yet achieved full RPM (revolutions per second), then this centrifugal force will not be sufficient enough to assist the separation.
4. Back Pressure: The back pressure ought to be adjusted following your purifier begins. The back pressure varies as the temperature, density, viscosity of feed oil inlet varies. The back pressure ensures that the oil paring disc is immersed within the clean oil along the way of pumping to the clean oil tank.
5.




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Throughput of oil feed: Throughput means the number of oil pumped to the purifier/hr. In order to optimize the purification, the throughput have to be minimum.
Before starting a Purifier, following checks have become essential:
1. If the Purifier commences after a overhaul, then check all fittings are fiited in right manner. The bowl frame hood locked with hinges.
2. Check the Oil level inside the gear case. Ensure that it can be exactly half inside sight glass. Also ensure that the sight glass is within vertical position, as there can be a common mistake of fixing it in horizontal position.
3. look into the direction of rotation with the seperator, by simply starting and stopping the purifier motor.
4. Check perhaps the brake is released position.

1. Ensure the lines are set and respective valves are open. Usually the lines are set from settling tank to service tank.
2. Start the purifier feed pump using the 3-way re-circulation valve able leading to settling tank.
3. Open the steam for the heater slightly ensuring the drains are open so the condensate drains. close the drains once steam appears.
4. Start the Purifier.
5. Check for vibrations, look into the gear case for noise and abnormal heating.
6. Note the present (amps) during starting. It goes high during starting and then when the purifier bowl picks-up speed so when it reaches the rated speed, the actual drawn drops on track value.
7. Ensure the feed inlet temperature has reached optimum temperature for separation as stated inside Bunker report and nomogram ( bunker delivery note increases the density in the fuel and taking advantage of this we can easily get the separation temperature and gravity disc size through the nomogram)
8. Now check whether or not the bowl has reached the rated speed by studying the revolution counter. The revolution counter provides the scaled down speed in the bowl. The ratio for calculation can be obtained through the manual.
9. Now, as soon as the bowl reaching the rated RPM, check for the actual attaining its normal value.


10. Open the bowl closing water/operating water, which closes the bowl. (Ensure sufficient water is present within the operating water tank)
11. Now after 10 seconds, open the sealing water towards the bowl.
12. The sealing water must be kept open till the water comes out in the waste water outlet.
13. Once the water overflows through the waste water outlet, stop the sealing water.
14. Now open the de-sludge water/bowl opening water. (This is done to ensure that the bowl has closed properly). During de-sludge we can easily hear a characteristic sound on the opening in the bowl.
15. Repeat the steps 10, 11 ,12 & 13.
16. Open the 3-way re-circulation valve such that the dirty oil feed is fed into the purifier.
17. Wait for a corner pressure to formulate.
18. Check for overflowing of dirty-oil through waste water outlet & sludge port.
19. Now adjust the Internet Page throughput to your value specified in the manual. Correspondingly adjust a corner pressure, too.
20. Now the purifier is put into operation. Change within the clean-oil filling valve to service tank.
Checks after starting the purifier during regular watches:
1. Adjust the throughput, back pressure, temperature of feed inlet if necessary
2. gear case oil level, motor amps, general leakages, vibration have to be monitored



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3. De-sludge every a couple of hours for heavy oil purifiers & every 4 hours for lubricating oil purifiers. (Rrefer to the manual or chief engineer instructions.)
Stopping of Purifiers:
1. De-sludge the purifier after stopping the feed inlet.
2. Shut down the steam inlet towards the oil.
3. Stop the purifier after completing the bowl with water.
4. Apply brakes and convey up the purifier to complete rest.
5. If any emergency, the purifiers has emergency stops, on pressing it, will eradicate the purifiers immediately shutting off of the feed.
Thus we have seen in detail how to begin the purifier after carrying out all safety checks and that we have also seen how you can stop it.