Lesson 230 - Mechanical Skimmers

Mechanical skimmers use a pick-up mechanism to draw surface oils from coolant.

That pick-up mechanism can be one of many shapes and made of one of many materials as long as the material is oleophilic, meaning it attracts oil. Zebra’s mechanical technologies include disk, belt, and tube skimmers.

Disk Skimmers

The L-Series Disk Skimmer was our first skimmer, and was designed to use the smallest footprint possible. Disk skimmers have been around for many years, and the L-Series is a favorite among customers, particularly those on a very tight budget.

We developed the GS-Series Smart Disk Skimmer to include a mini oil/water separator, called the Diverter. Earlier we discussed types of coolant and how each has its own percentage of base oils, which are also attracted to mechanical skimmers. The Diverter will re-separate this coolant and ‘divert” it back to the sump, reducing coolant waste. The Smart Disk Skimmer is a new favorite among disk skimmer lovers, as it is also very economical.

Both disk skimmers are offered in various sizes and can be equipped with a continuous-duty motor, even if not a standard.

Zebra is proud to offer a lifetime warranty on replacement disks and wipers, including those purchased as replacements for other brand units.

Belt Skimmers

The Zebra Belt Skimmer uses a belt on a pulley system to skim oil. This traditional technology allows the unit to fit into areas where disk skimmers cannot. Belt skimmers are also suitable when skimming oil from drums of coolant, or other applications where there is a fair distance between the mounting point and the fluid level. Belts are offered in various widths and reaches to tackle almost any coolant job. A lifetime warranty is offered on replacement wipers for this unit as well.

The Diverter is available as an accessory, and is always recommended for coolant applications where there is room for it.

Sidewinder Tube Skimmer

Topic 121 introduced the ZVA Sidewinder Tube Skimmer, which uses a tube that is driven by a gear system. Although tubing has long been used in larger industrial and wastewater applications, Zebra was the first to use this technology in machine sumps, as it is flexible enough to overcome the problem of very limited sump access. Many machine builders are incorporating coolant tanks underneath the machine to save floor space, and this is where the Sidewinder works better than any other mechanical skimmer. Sidewinder is a very popular tube skimmer, yet there are many customers who have not yet been introduced to it. It is also offered the unit with long tubes to skim oil from almost anywhere.

The Diverter is also available for use with Sidewinder. However, due to tank access some customers are unable to use the Diverter. Zebra offers slower motors on Sidewinder to help reduce coolant loss in these situations.


All of our mechanical skimmer technologies will handle the daily oil introduced by machine ways and hydraulic systems. Coolant loss can be minimized by selecting a skimmer which has exactly the oil removal capacity needed, as well as incorporating a Diverter whenever possible.

We recommend that any skimmer, whether or not it has a fan-cooled motor, be timed to run only as long as needed. This will increase motor longevity. If possible, the timer should be set to start the skimmer when the sump has had a few minutes to settle, after oils have a chance to rise to the surface.


What Fits?

Practicality dictates that “what fits” is the place to start when selecting a skimmer for an application. Whenever possible, the skimmer should skim from the area in the tank where oil naturally collects. If this area has plenty of access, a Zebra Disk Skimmer may be the cheapest option. If there’s somewhat limited access, then a Zebra Belt Skimmer may be better. For machines with very tight access, particularly overhead, the Sidewinder will easily ‘snake’ in there to get the job done.

How Much Oil Removal is Needed?

Next, consider the skimmer’s oil removal capacity. In general, all of Zebra’s skimmers will have appropriate, even extra, oil removal capacity for applications at the sump level. Large sumps or central tanks may need a closer look to determine how much oil removal capacity is required.

How Much Reach is Needed?

Also consider the distance from the skimmer’s mounting point to the lowest level of the fluid. We refer to this as ‘reach’ because we have to reach the fluid surface to skim the oil. When the skimmer is mounted on the oil waste container, this container becomes the mounting point. Both the Zebra Belt Skimmer and Sidewinder have more flexibility regarding reach than our disk skimmers.

selecting a mechanical skimmer

Other Considerations
Tank configuration is the last consideration. Oil spreads more thinly across very large surfaces. A skimmer with a larger pick up mechanism, such as a wider belt, may be necessary to create surface ‘pull’ of that thin layer of oil. Or you can use multiple units, placing them in the most strategic locations for effective oil removal.

The above recommendations hold true for elongated surfaces. However, when this surface is also fairly narrow, the Sidewinder may be best, with the washer on the end of its tube secured at a diagonal at the opposite end of the tank. This way, it also handles any fluid fluctuation, or flux.

For baffled tanks, small notches may be cut near the top of each baffle to provide for better surface communication. Or, the Zebra Fluid Transfer Kit may be an option. It uses a pump and an intake attachment–normally used with a coalescer–to draw oil from this section and dispense it to the section having a mechanical skimmer. This setup also works well for totally divided tanks.

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