FRIESS oil separator Skimmtelligent used at central emulsion tank

A big manufacturer of components for engine and drive train uses a central emulsion tank with a volume of 30 m³ emulsion. The emulsion does not work as coolant, but as quenching media in a hardening process. In order to ensure the quality of the parts, the emulsion must not contain more than 50 l tramp oil.

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If the percentage of tramp oil is too high, the hardening quality is too low and there are soft spots on the parts. Because of the strong turbulences in the central filtration system, the tramp oil does not float on the surface, but it is mixed with the emulsion. The production manager was looking for a system that is able to reduce the tramp oil in the emulsion down to less than 0.1 % in order to avoid soft spots on the parts.

Solution: Skimmtelligent oil separator

A big suction device made of stainless steel floats on the surface of the emulsion. The emulsion is pumped with a diaphragm pump from the suction device into the oil separator Skimmtelligent.

Compared  to centrifugal pumps, the diaphragm pump has the big advantage that the oil droplets in the emulsion will not be destroyed and separated into smaller oil droplets.

The displacement pump does not destroy the  oil drops and the separation of the tramp oil is much more efficient. In case that the volume of oil drop is reduced by 50 % the uplift of the smaller oil droplets is reduced by 75 %. The separation of the smaller  droplets is much slower than the separation of the bigger oil drops.

Coalescing elements for the finest oil droplets

Inside the oil separator, the flow of the emulsion is very slow so that the oil droplets have enough time in  order to float to the surface of the emulsion. Because of using coalescing media, the uplift of the fine oil droplets is accelerated. The emulsion contaminated with small oil droplets flows through the coalescing  media. The small oil droplets stick to the surface of the coalescing media. The small oil droplets do not  have enough uplift so that they do not float to the surface. The flow resistance in the emulsion is bigger than the small uplift of the small oil droplet.

Because of the high viscosity of the oil droplets compared to the emulsion, the small oil droplets will stick much better to the surface of the coalescing media in the emulsion. The emulsion flows through the coalescing media, while the oil droplets stick to the surface of the coalescing media. Many small oil  droplets on the coalescing medial form bigger oil drops. The bigger oil drops have more uplift, and they are separated on the surface of the emulsion. After passing the coalescing media, the emulsion flows back by gravity into the central emulsion tank.

The separated oil floats on the surface of the emulsion in the separation chamber. In many conventional oil separators, the floating oil should flow over a baffle into a waste oil tank. The height of the baffle has to be adjusted to the height of the liquid level in the separator. If the height of the baffle is too low, many oil will flow into the waste oil tank. The result is high consumption of emulsion and high cost for disposal.  If the baffle is adjusted too high, a very thick oil layer floats on the surface. The emulsion underneath has no contact to the oxygen in the air, and anaerobic bacteria will grow very fast.

For this reason, the oil separator Skimmtelligent is equipped with Friess oil skimmer model 1U in order to remove the floating oil. The floating oil sticks to the outside of the oil collector tube of the oil skimmer.  The oily oil collector tube is drawn into the oil skimmer. The collected oil is removed with scrapers from the surface of the oil collector tube. The oil flows from the scrapers into a waste oil collecting tank. The oil collector tube returns to the surface of the emulsion and picks up new oil. The operating time and the idle time can be set individually for each application so that the capacity of the oil skimmer fits exactly to the oil volume that is separated. The contamination of the waste oil with emulsion is very low, and the disposal costs are low as well.


Result through the use of the FRIESS oil separator Skimmtelligent

Since using the oil separator Skimmtelligent 40 the level of tramp oil in the emulsion is much lower than 0.1 %. Typically, the content of tramp oil is less than 0.03 %. The number of rejected parts caused by oil  in the emulsion was drastically reduced. The payback time for the oil separator Skimmtelligent was less than 6 months. In addition to that, the service life of the emulsion was raised to 1 year.