Racor Turbine Series: The Inside Story
Time for a refresher course on Racor Turbine Series internal operation and function. The unit pictured is a Racor 900 Series. For clarity, the internal latching valve below the element in this illustration is not shown, but it still serves well for a understanding the fuel flow path.
There are three filtration steps that fuel must pass through in order to be Racor Clean and Dry:
1. As fuel enters, it moves past the internal check valve. The internal check valve ball floats in fuel and therefore is always trying to float up to the seal. When flow stops, the ball is in contact with a seal, stopping any fuel flow back to the tank. When the 900/1000 priming pump (RKP1912/24) is used, a light spring is included to keep the ball up against the seal. This allows the priming pump to do its thing when the assembly is still full of air. After the check valve ball, fuel flows down through the “turbine” where the fuel is sent in a spiral motion; spinning off larger particulates and water droplets to collect on the inside of the bowl. This separated contamination, being heavier than fuel, falls to the bottom of the bowl for draining. One more note: the “turbine” is not a mechanical device and does not move. Spiral flow is induced by internal vanes inside the turbine, and they do all the contaminant separation without mechanical movement.
2. Smaller water droplets, being carried by the fuel flow, tend to bead-up on the sides of the bowl, the coalescing cone, and on the surface of the Aquabloc filter element. These drops collect and merge together until they are large enough to drop down past the fuel flow. They can then fall to the bottom of the collection bowl to be drained as needed.
3. Fine solid contaminants that do not fall into the bowl immediately, are also carried with the fuel flow until they are stopped at the surface and sub-surface of the Aquabloc media element, at a rate and size that depends on the micron rating being used. Asphaltene-like soft solids, naturally present in diesel fuel, are known to be the main cause of element plugging. A special Aquabloc surface fiber design prolongs element life by resisting asphaltine plugging and is the reason Racor filters have such long life.
Now that wasn’t so bad. Now you know how a Racor Turbine Series works on the inside.