Choosing a Coolant Oil Skimmer for the Machine Shop
Advantages of Using Coolant Oil Skimmer for Machine Shop
Coolant oil skimmers for machine shop use offer many benefits. They help remove oil from coolant tanks and improve shop conditions. Removing oil can also reduce smoke when the cutting tool contacts oil-laden coolant.
When a machine is off for the weekend, oil rises to the surface of the coolant tank. Bacteria in the tank consume dissolved oxygen faster with oil on the surface. This creates ideal conditions for anaerobic bacteria, which produce a “rotten egg” smell.
Most bacteria in metalworking fluids don’t cause dermatitis. However, broken skin can become infected by normal skin bacteria. Coolants with phosphates and carbonates can irritate skin and cause dermatitis. These impurities often come from the water used in the coolant mix.
Separating oil from coolant reduces disposal costs. Oil-laden coolant is more expensive to dispose of than oil alone. Some companies can reuse or sell the separated oil for recycling.
Clean coolant lasts longer and reduces maintenance and replacement costs.
Choosing a Coolant Oil Skimmer
When researching coolant oil skimmers for machine shop use, it becomes clear that there are several types available. The most common are belt, disk, and tube skimmers—each with its own advantages and disadvantages depending on the application.
Coolant oil skimmers for machine shop use must be carefully selected by considering several factors such as water level fluctuation, water temperature, pH level, the use of rust inhibitors, the amount of oil to be skimmed, as well as the skimmer’s quality and cost.
Choosing coolant oil skimmers for machine shop involves understanding how factors like rust inhibitors, high temperatures, and variable pH levels can affect the skimmer’s ability to remove oil. Most skimmer manufacturers use various materials for the skimming medium—such as plastic, stainless steel, or poly blends—to suit the specific solution conditions.
There are a multitude of oil skimmers on the market today. One of the most important aspects to consider when using a coolant oil skimmer for a machine shop is the overall quality of the unit. Key factors to examine include construction materials, motor design, and the type of warranty the manufacturer provides. Is the skimmer housing metal or plastic? Does the motor include a fan for cooling? Does it use needle bearings or bronze bearings? How long does the warranty last, and what exactly does it cover? Most oil skimmers perform as advertised, but remember the old adage: “You get what you pay for.”
Common Coolant Oil Skimmer Used in Machine Shop
Tube Oil Skimmers – Coolant Oil Skimmers for Machine Shops
The tube skimmer works by mounting to the side of a coolant tank and running an endless, small-diameter tube (typically Tygon) onto the surface of the coolant. The tube collects the oil and carries it back to the skimmer, which then removes the oil and deposits it into a proper disposal container.
Mounting this skimmer on the side of a machine coolant tank is its biggest advantage, allowing it to operate where vertical access isn’t possible.
Its biggest disadvantage is the minimal oil pickup rate (approximately 1 quart in 24 hours). The user must also cut an access hole into the side of the coolant tank, which can lead to coolant spillage. The cost of this unit is similar to other coolant skimmers.
Disk Oil Skimmers – Coolant Oil Skimmers for Machine Shops
The disk skimmer works by mounting to the top of the tank and running a large-diameter disk into the coolant surface. The disk typically consists of plastic or stainless steel. As the disk passes through the coolant surface, it picks up oil, which is then wiped off by a set of wiper blades as the disk moves between them.
One advantage of using the disk skimmer is its slightly higher pickup rate (approximately 1½ gallons per hour in optimal conditions) compared to other types of skimmers. Another benefit is its generally lower cost.
However, the disk skimmer also has some disadvantages. It requires a large operating space—for instance, a 24″ diameter wheel is needed to reach a depth of about 12″. The pickup rate drops significantly if the water level doesn’t cover at least half the disk surface, making it less suitable for tanks with fluctuating water levels. Standard plastic disks can’t withstand high operating temperatures, such as those in parts washers, and stainless steel replacement disks are often expensive.
Belt Oil Skimmers – Coolant Oil Skimmers for Machine Shops
The belt skimmer works by mounting to the top or edge of a tank and running an endless belt (made of plastic, stainless steel, or poly material) into the tank. A motorized head pulley and a free-turning tail pulley hold the belt in a vertical position. As the belt travels through the surface of the coolant, it collects oil. The belt then passes through a pair of wiper blades, which wipe oil off both sides of the belt.
Some advantages of using a belt skimmer include its compact size, which requires very little operating space. Belt skimmers offer good oil pickup rates (up to 2 gallons per hour, depending on belt width). This type of coolant skimmer handles fluctuating coolant levels while maintaining minimal space requirements and maximum pickup capacity. Most belts are made of stainless steel, allowing the unit to operate in high temperatures without extra cost. Belt skimmers generally cost about the same as other types.
There really are no disadvantages to using a belt skimmer compared to other types. The pickup rates are comparable to—or even better than—other skimmers, and the pricing is competitive.
In summary, when choosing the appropriate oil skimmer, customers must consider the specific application. They should assess factors such as tank size, coolant access, oil removal rates, and the other details discussed above to select the most suitable coolant skimmer.
By Christopher Ott, Product Manager
Abanaki Corporation; Oil Skimmer Division
