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Difference Between Separators & Clarifiers?

written by: Raunekk • edited by: Lamar Stonecypher • updated: 1/12/2010

Separators and clarifiers are used for the same purpose - purification of fuel oil on ship. So what is it that makes them as two separate equipments? Learn about the main dissimilarity that sets the two equipments apart.

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    An efficient combustion in marine engines requires a perfect quality of fuel oil. The heavy oil used in engines is not of the purest form. The fuel oil is sent through a series of purifying equipments before it reaches the engine. Separators/purifiers and clarifiers are two such equipments that are used for purifying and filtering the fuel oil of all the dissolved impurities. However, if the separator and clarifier both perform the same function of cleansing the fuel oil, what is the difference between them? Let’s find out.

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    What is a Separator and a Clarifier?

    Basically, a clarifier is attached just after the purifier in the fuel line. While the main function of a purifier is to separate the dissolved water, impurities and sludge from the fuel oil, a clarifier removes any solid foreign material that is not removed from the oil after it passes through the purifier. Thus a clarifier is kind of a back up system for purifying fuel oil. However apart from these there are a few more prominent differences that set the two of them apart.

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    Main Differences

    The main difference between a clarifier and a purifier is the presence of a dam ring in the latter. In a purifier, the interface or the line of separation between the oil and water is created using a dam ring. The position of the dam ring plays an important role in the generation of interface and thus in the clarifying process. For example, if the diameter of dam ring is large, the interface moves out towards the periphery and as a result some oil is discharged with water from the water outlet. Also, if the diameter is small, the interface formed will be more inwards and water will be discharged with the oil from the oil outlet.

    The diameter of holes in the dam rings also plays an important role in the creation of interface and purification process. If the diameter of the holes is more, the interface is formed towards the periphery and oil globules are found with water and sludge. If the diameter is less the oil-water interface moves inwards and water is released with the clean oil discharged.

    However, clarifiers do not have a dam ring but have a sealing ring which seals the water outlet. This prevents the impurities and water to remain inside the bowl unless they are discharged automatically or manually by opening the cleansing bowl. Also, the conical discs in a clarifier usually don’t have feed holes in them but if they do, then a disc without any holes is fitted at the bottom of the stack.

    Another difference between a clarifier and purifier is that a purifier needs to be filled completely with water for the generation of a seal that prevents the oil to leave from the water outlet. Whereas a clarifier doesn’t needs to be filled up with water. Purifiers are used for filtering lubricating oil whereas clarifiers are not used for the same unless the oil is completely devoid of water.

    purifier dam ring 

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