Recycling fluids with the Bernoulli Effect

At Ford’s Dearborn plant, a giant 2,600-ton Schuler press with up to 300 tons of dies turns 700,000 lb of steel per day into doors for F150 pickups. Stacks of steel blanks arrive at the press area. Each blank is coated with a thin film of mill oil to protect against corrosion.

Prior to stamping, the blanks are spray-washed with a detergent. The solution returns to a holding tank where the Suparator from ARR removes the top portion of the flow. This portion carries all the oil. Water and oil (traces) flow into the first compartment. Water is sucked out of the compartment through an opening at the bottom. The oil, still with fairly high concentrations of water and chemicals, forms a floating layer of considerable thickness. Water and chemicals migrate towards the interface and reenter the water flow. Finally, the upper portion (pure oil) of the floating layer is skimmed off. Contaminants in this concentrated stream continuously separate from the fluid, without water or detergent.

At the Hydraulic Pump/Motor Div. of Parker Hannifin Corp., a Lindberg washer used intentional overflow of the cleaning bath to remove quench oil. Unfortunately, this resulted in the loss of cleaner and added large amounts of water to the plant’s effluent, according to Larry McCracken, plant engineer. The company eliminated the continuously overflowing bath, but it needed an alternative.

“Initially, we tried a belt-type skimmer, but that was unsuccessful,” says McCracken. “So, we tried a Suparator, and it removed about 10 gallons of quench oil per day. It reduced operating costs and gave us cleaner parts.” Water consumption went from 19,080 gallons per month to only 3,480. Chemical losses went from 298 gallons/month to 54 — a savings of almost 82%. And water-disposal costs decreased about 80%. The company says annual savings have been at least $100,000.

Blaine Timmerman of Bodycote, a provider of metallurgicaltesting and thermal-processing services, says their Rochester, N.Y., heat-treating facility generates savings from dynamic separation. Timmerman explains that in the past their heat-treating process tended to create a rag layer between the oil and water in the dunk/spray washer. “We would get this nasty in-between layer that was an emulsification of water in oil. It didn’t completely separate into the oil or the water. It tended to stay sandwiched between the two. That hindered oil separation because the emulsified layer would roll down the skimmer rope or plate and return to the water.”

“We tried just about every oil separation technology,” says Timmerman. “Conventional oil separators didn’t meet our needs. We paid a stiff penalty to dispose of oil with high water content. Several years ago, relatively dry oil disposal cost about 15 cents a gallon. But, because of the water drag-out of our old oil separators, we were getting wet oil. If the oil had more than 10% water, which was often the case, we had to pay around $1.05 per gallon.”

In addition to eliminating the rag (emulsified) layer and the water drag-out, dynamic separation lets the company reuse the bath water several times.