T.S. Patriot State Engineering Manual

Patriot State was the training ship of the Massachusetts Maritime Academy from 1986 to 1998.

Lube Oil Purifier

Lube oil does not wear out! However, its lubricating quality tends to deteriorate over time due to contaminants such as dirt, sludge, metals, and water to name just a few. There are many different ways to remove these contaminants, some being more effective than others. Common methods include; strainers, filtration, settling tanks, and centrifugal type purifiers.

In the centrifugal purification process, there are two common methods used. One method is the batch purification process where all of the oil is removed from a storage tank (sump, settler, etc.) by the purifier and is delivered cleaned to another reservoir. This method is typically done on machinery that is not operating. The other method is the continuous process where the centrifuge takes a portion of the oil from a tank, cleans it, and recycles it back to the same tank. This method can be used on operating equipment but is not as fast or efficient as the batch process.

Centrifuges can also be used as Separators or Clarifiers. Separators use a dam ring or discharge ring and remove water as well as solids from the oil being purified. The water is discharged from the purifier. A clarifier is used when the main contaminant is sediments, and water does not need to be removed from a system. Any small amounts of water that does enter the centrifuge will remain in the bowl until it is cleaned.

Centrifugal purifiers as sometimes catagorized as disk-type or bowl-type purifiers according to the shape and general arrangement of the centrifuge, and some purifiers are self-cleaning, while others must be manually cleaned.

Aboard the Patriot State, we have a disk-type, non-self-cleaning purifier manufactured by DeLaval, and used as a separator in the continuous process.

In a a disk-type purifier, a bowl shaped rotating element encases a stack of disks. The bowl itself sits atop the vertical bowl spindle which is driven by a worm gear and clutch assembly. The spindle and bearing absorbs the weight of the bowl assembly. Once operating, the bowl spins at approximately 7500 rpm. As liquids and sediments of different densities enter through the distributor (the inner most center of the bowl housing) of the centrifuge, they are quickly separated by the tremendous centrifugal force created by the velocity of the centrifuge, and also by the close separation created by the shallow distances of the individual disks inside the bowl housing. The clean oil travels up between the neck of the top disc and the tubular shaft/distributor. If the centrifuge is operating as a separator, the water will discharge out between the neck of the top disc and the discharge ring mounted at the uppermost section of the bowl top. Sediment, sludge and other materials will be moved to the inside of the bowl shell and will remain there till cleaned. It is important to note that the size of the discharge ring must be properly matched for the density of the lubricating oil to be purified. If you are to use the purifier to centrifuge other oils with different specific gravities, a different discharge ring must be used for each.

Lube Oil Purifier Specifications

Manufacturer         DeLaval
Model                65N-03
Capacity             300 GPM (250 SSU at 130 °F)
Outlet pump          25 psig
Suction lift         15" Hg
Motor                1 HP. 440 VAC, 3, 1800 rpm

Lube Oil Purifier: Operation

Lube Oil Purifier Bowl: Sectional View

Lube Oil Purifier Bowl: Exploded View

Lube Oil Purifier: Sectional View

Lube Oil Purifier: Discharge Ring Sizing Chart

Lube Oil Purifier Operation

The following procedure is used to start the lube oil purifier aboard the Patriot State.

  1. All of the internal running parts of the purifier are automatically lubricated by a mist or spray caused by the helical gear running in a reservoir of oil. This reservoir must be checked and filed before operating the purifier. To fill the reservoir, unscrew the filler cap (with dipstick) and pour oil into the lube oil reservoir. It will take about 1 quarts of oil to completely fill the reservoir. Make sure that the reservoir is not overfilled when done and also make sure to replace the cap/dipstick. This should not be done while the purifier is operating!
  2. Check that the brake and lock screws have been released, open the purifier, inspect, and make sure that the bowl is properly reassembled and that the bowl revolves freely.
  3. Clamp the cover and inlet arm down firmly
  4. Open all valves for the discharge pump and the tank it supplying.
  5. Open all valve for the suction pump and the tank its receiving from except the inlet valve for the suction pump.
  6. Start the pump and check for the speed by depressing the speed indicator. The plunger should indicate not less than 70 times per minute..
  7. Prime the bowl by adding water to the funnel at the top of the purifier. The bowl is completely primed if water drains from the discharge port.
  8. Open the inlet valve slowly. Maintain a discharge head of 6-8 psig.
  9. The temperature of the lube oil should be maintained between 160-165° F. The oil discharge port should be 1/8 full and the water discharge port should have no oil in it and little or no water. (a large amount of water would indicate water contamination of the oil being purified and should be investigated.

Lube Oil Purifier System

Direct comments to William Haynes whaynes@maritime.edu
Mon, Jul 1, 1996
TSPS Engineering Manual ©1995 Massachusetts Maritime Academy