Removing Oils for Longer Solution Life

Industrial parts cleaning systems are designed in many different sizes and configurations, and in most cases they all share one common trait: the accumulation of tramp oil. Tramp oil originates when parts are exposed to oil-based coolant, stamping/forming lubricants, or other oil-based products that are used in manufacturing operations. These oils collect within the wash tank as they are removed from parts during the cleaning process. With oil-splitting chemistry, oil will rise to the surface due to it being a lighter specific gravity than water. In order to maintain an effective cleaning system, oil must be regularly removed from the wash tank. Removing the oil extends the life of the cleaning solution along with preventing the oil from re-depositing back onto other parts. Not removing the oil increases costs due to excessive machine down-time and needing to refill the tank with fresh water and cleaning chemistry.

Two of the most common products used to remove tramp oil are oil skimmers and oil coalescers. While both are effective, their designs and oil removal methods are unique.

Oil Skimmers

An oil skimmer is used when cleaning parts containing small amounts of residual oil at low production rates, resulting in a slow accumulation of oil within the wash tank. Low production part cleaning enables the cleaning system to be taken off-line for a period, allowing the oil to separate from the water and float to the top of the tank, where the oil skimmer will remove the floating oil.

Oil skimmers come in two basic designs, belt skimmers or disk skimmers. Both are externally mounted to the top of the wash tank allowing the oleophilic (oil-attracting) belt or disk to extend into the cleaning solution where the floating oils are extracted.

Belt skimmers: As the belt runs vertically through the cleaning solution, the oil clings to the face of the belt as it exits the solution, and then passes by an externally mounted wiper where the oil is scraped off the face of the belt and it is collected into a waste container for disposal. Belt skimmers are popular since they take up little space when mounted to the exterior of the machine, the belts are available in varying widths for different oil removal rates, and the belts can be purchased in varying lengths to ensure effective oil removal even as the solution levels fluctuates inside the tank.

Disk skimmers: Disk skimmers operate by rotating a large, partially submerged disk into the cleaning solution. The oil clings to the face of the disk, and then passes by an externally mounted wiper where the oil is scraped off and collected into a waste container for disposal. The advantage of a disk skimmer is a slightly higher oil pick-up rate, since the diameter of the disk can be increased for greater oil removal. However, disk skimmers require a large area to mount onto the machine, based on the diameter of the disk. A notable disadvantage is that the oil removal rate drops dramatically if the solution level does not cover at least half of the disk surface, making it unsuitable in tanks where the solution level fluctuates.

Alliance Manufacturing offers our high-capacity Aquaskim B400 belt-type oil skimmer that can be used on any of our industrial parts cleaning systems. The Aquaskim utilizes a 4-inch wide stainless steel belt which is offered in various lengths and comes with a lift-off corrosion-resistant fiberglass cover for quick and easy maintenance. The Aquaskim is designed to remove oil at a rate of up to 6 GPH, based on oil viscosity.

Oil Coalescers

Oil coalescers are used when cleaning parts containing moderate to large amount of residual oil at high production rates, resulting in a quick accumulation of oil within the wash tank. Cleaning systems used in high-production parts cleaning usually run continuously with no or minimally scheduled downtime, resulting in larger amounts of oil accumulating on the surface of the solution. Oil coalescers operate alongside the cleaning system to separate and remove oil from the solution.

As the parts are processed through the cleaning system, the oil coalescer continuously recirculates the solution from the wash tank through the oil coalescer and back to the wash tank. The oily solution is processed through a series of weir plates that progressively remove the floating oils and the oil-free solution is then gravity drained back to the wash tank. The oil that is removed during the separation process is directed to a waste container for disposal. Oil coalescers are designed in various sizes offering different oil removal rates. The volume of the cleaning system solution tank determines which size of oil coalescer should be used to efficiently remove the oil from the solution.

Alliance Manufacturing offers our Aqualescer oil coalescer that can be used on any of our parts cleaning systems. The Aqualescer is cost-efficient by conserving the cleaning solution while eliminating tramp oils. The Aqualescer is manufactured in stainless steel including removable coalescing plates for ease of cleaning. The Aqualescer is designed in five different sizes, offering oil removal rates of 0.5 GPM to 3 GPM based on oil viscosity.