Oil-circulation lubrication is often used by the pulp and paper industry to lubricate machine components such as gear reducers, dryer rolls, felt rolls, and wire and press-section rolls. The systems must withstand high temperatures and eliminate contaminants such as abraded and oxidized particles, water, and air bubbles.

Traditional reservoir systems with square tanks often keep less than half of the oil circulating effectively. And, due to channeling effect, retention times are short, typically less than 10 min which is not long enough to remove impurities.

However, in the new design, called the Safematic Flowline Oil Circulation system, a series of concentric platelets in a round reservoir provide a shorter distance for air and water to travel to separate. The reservoir is actually less than half the size of traditional tanks yet significantly improves the ratio of oil used in the system. At the same time, the Flowline reservoir separates and eliminates air and water bubbles, protecting the oil and providing better lubrication.

In fact, research shows that compared to a conventional system with a 1,600-gallon volume reservoir, the Flowline system with an 800-gallon reservoir has greater retention time. And, when comparing a 4,800-gallon conventional system to John Crane Safematic's 1,600-gallon model, up-front oil filling and handling cost savings can amount to as much as $84,000 with the new system, say company officials.

Several intermediate plates inside the new round tank return oil flowing from the center to the sides of the tank.

Because the distance between the plates is very small, the water drops in the oil have only a few inches to sink before meeting the next plate.

After that, the water drops collect slowly to the corner point and through the drain channel to the tank bottom. With this design, only a few minutes of retention time is needed to separate the free water from the oil. In the same way that the plates separate water downward, they separate air bubbles upward.