Reducing water usage is an essential ingredient of productivity and profitability, to conserve water and to reduce treatment and disposal costs. Separating and removing contaminants such as oil, grease and dirt can increase the lifespan of water-based coolants, cleaners and lubricants.
Mechanical separation methods typically are based on one of two principles: gravity separation in combination with weir skimmers and tank overflow; or adhesion, using hoses, wheel/disks or belt skimmers that attract oil to lift it from the surface of a bath. Both methods are problematic, particularly in high-volume production settings where delays are required to change or maintain aqueous baths involve downtime.
For instance, adhesion separation often allows dirt to settle through surface oil and cycle back into the bath water, leading to dirty parts and a need for frequent solution changes. The adhesion method also draws up and removes cleaning agents along with water and oils, producing “wet” oil and adding to oil disposal costs.
The overflow (decanting) method can waste significant amounts of coolant or cleaner from the bath. The coalescing-media method, which uses honeycomb-like traps or plates to separate and capture oil and contaminants, often is inefficient and maintenance-intensive because of its sensitivity to dirt.
At Parker Hannifin Corp.’s Hydraulic Pump/Motor Division in Greeneville, Tenn., a Lindberg washer used intentional overflow of the cleaning bath to remove quench oil from heat-treated parts. This resulted in loss of cleaner and “excessive volumes” of water being added to the plant’s effluent, according to Larry McCracken, plant engineer.
To reduce the costs resulting from those cleaning and disposal problems, the washer was modified to eliminate the continuous overflow. However, some method was needed to control oil accumulation in the bath.
“Initially, a belt-type skimmer was tried, but was unsuccessful,” says McCracken. The company contracted with Aqueous Recovery Resources (ARR, www.superator.com) for a 30-day trial of its Superator dynamic separator.
Dynamic separation operates on the Bernoulli Effect, where increased fluid velocity results in lower internal pressure. This pressure differential enables separation of liquids of differing specific gravities, such as oil and water. Much of the dirt and other foreign matter are separated with the oil, giving a cleaner process and cleaner parts, translating to better quality and fewer rejects.
“Approximately 10 gallons of quench oil is removed from the bath daily,” says McCracken. “This result has greatly reduced operating costs as well as our getting cleaner parts from the washer.”
Cost savings included reduction in water consumption from 19,000 gallons to 3,500 gallons per month. Chemical losses, previously recorded at 300 gallons per month, were reduced by 240 gallons, a savings of almost 82%. The monthly cost of water disposal was reduced by approximately 80%, and the monthly cost of chemicals reduced by more than 80%. The total annual savings has been at least $101,184.
A video showing how the dynamic separation technology works may be found at www.suparator.com/video/plexi-model.wmv.