Situation: Lindberg Heat Treating Co., Rockford Div., Rockford, Ill., cleans its heat-treated and oil-quenched parts in heated spray wash tanks, which over time become contaminated with the quench oil. This created various problems including the need to shut down the tanks periodically to drain and clean them and fill with fresh solution and to discard the contaminated wash solution. The company also had the expense of purchasing new quench oil. It needed a plan to cut the costs of materials, maintenance and downtime.
- Reduce the consumption of quench oil and associated expenses
- Reduce downtime for cleaning
- Reduce fluid-disposal costs
- Reduce maintenance costs
Solution: The company turned to Abanaki Corp., a manufacturer of industrial belt oil skimmers to help solve its problem. Abanaki recommended using its Model 8 Oil Grabber to remove quench oil in Lindberg's heated spray wash tanks. The oil skimmer is a dependable and effective means of removing oil from water and water-base solutions. Using the oil skimmers on the wash tanks enabled the company to recover 70% of its quench oil from the washing solution, materially aiding its energy conservation program.
Oil skimming makes use of the differences in specific gravity and surface tension between oil and water. Operation of the oil skimmer is based on the principle that oil is attracted to and will adhere to metal better than water. The skimmer's endless metal belt draws the oily wastes up out of the liquid being cleaned, over the head pulley and past doctor blades, which remove the oily residue from both sides of the belt. The oil drains into a trough from which it flows to a collecting tank or drum. A single unit elevates and separates oil. In addition, the unit maintains skimming efficiency with fluctuating fluid level and it can operate in a turbulent liquid. A vital part of the oil skimmer operation is the ability of the head pulley to drive the belt without interfering with oily residue on both sides of the belt. A free-riding tail pulley stabilizes belt operation but permits it to bend around floating obstructions that might damage permanently secured equipment.
Recovery and recirculation of 70% of the quench oil is considered an exceptionally high level of efficiency according to Mr. James Reh, Plant Engineer for the Lindberg Heat Treating Co., Rockford Div. According to Reh, the oil skimmers have become a vital step in the company's energy conservation program for recovery of oil previously discarded.
"In addition to saving more than 2/3 of the quench oil cost, Lindberg has saved countless hours of downtime formerly required to clean out their washer tanks every week. The tanks now run continuously for several months without requiring any maintenance," said Reh. The Rockford facility has 8 oil skimmers in operation on washer tanks. Lindberg also installed 3 skimmers at its Norwood, Mass., plant and one each at its plants in West Allis, Wis., and Minneapolis, Minn. All of the oil skimmers are equipped with 8-in. (200-mm) corrosion-resistant belts that remove up to 32 gal (120 liter) of quench oil per hour each.
Capacities of the oil skimmer range from 32 to 160 gal (120 to 600 liter) of oily wastes removed per hour, depending on the number of 8 in. belts on the unit. Because the endless belt is available in almost any length and the tail pulley is free riding, the skimmer can be furnished to accommodate any height requirement, depending on the depth of the liquid to be cleaned and the distance the oily residue is to be raised.