Troubleshooting Your Belt Oil Skimmer

Why isn’t my belt skimmer working properly?

At Abanaki, we know that skimmer downtime can affect your operation, and when your belt oil skimmer isn’t operating as intended it can be frustrating to try and figure out what’s going on.

Here are some of the most common problems we see, and how you can troubleshoot to identify and solve them. Because Abanaki’s belt skimmers rely on surface tension rather than pumps for oil collection, it is critical to monitor the unit’s mechanics to ensure their operating efficiency. Checking the unit regularly and performing routine maintenance will help keep your skimmer operating at its best over time. Things like oil changes, skimming media replacement (belt, tube, disk, etc.), motor replacement, and wiper replacement should be done at the appropriate times based on your skimmer’s model and runtime requirements.

My belt is slipping.

If the belt is slipping on your skimmer, check that the belt is passing through the wiper blades without any obstructions. Is the tail pulley able to turn freely without obstructions? Coolant and oil mixtures can be very slippery, but you can add a spacer (size depends on skimmer and belt width) between the spring and base plate for extra tension, which should add the resistance the belt needs to keep from slipping. When it comes to wiper blades, make sure not to overtighten them; they should make contact with the belt so that there is a slight bend as the belt passes through them, and the belt should be directly centered in the middle of the discharge troughs.

Another thing to check is whether the skimmer is mounted levelly. If it’s not, a free hanging belt won’t be able to track correctly over the pulley. Remounting the skimmer to be perfectly level should help. If you have a skimmer that has a yoke and chain (ex: Model 4 or Model 8) make sure that the belt is holding the weight of the tail pulley and that there is slack in the chain.

Finally, is there debris present? Be sure to check that the tail pulley is rotating freely and is free of any floating debris that could inhibit proper rotation movement.

Oil isn’t being collected like it used to.

If you notice a decrease in your unit’s skimming capacity, check that the wiper blades are making good contact with the belt or disk. The wiper blades should be tightened enough to contact the skimming media with enough tension to scrape oil off effectively, but wipers that are too tight will cause premature wear on both the media and the wipers themselves.

Additionally, check for debris, tears, and wearing in the wipers. When wipers are not in good operating condition, they cannot scrape oil from the belt effectively, and oil will end up back in the tank or sump.

Another thing to check on is if there are rust inhibitors present in the coolant environment—rust inhibitors, or chemical compounds that are applied or mixed with metals to prevent or slow corrosion, can coat stainless steel belts and prevent oil from being picked up. If this is the case, another belt material like Abanaki’s elastomer or polymer belts can help, as rust inhibitors don’t have the same sticking effect on these synthetic belt materials.

I just installed my skimmer, but it isn’t collecting the amount of oil I had in mind.

If your skimmer isn’t collecting the amount of oil you envisioned and appears to be in perfect working order, it might be too small. We’ve actually written another blog post on this topic which you can read here, but purchasing a small skimmer based solely on gallons-per-hour skimming capacity can create long term skimming inefficiencies that outweigh any initial purchase savings.

An oil skimmer should have the capacity to remove at least twice the amount of oil required in your specific application to account for condition fluctuations and performance longevity. A good rule of thumb is that when selecting a skimmer, be mindful that you’re making a decision based on the size of the area to be skimmed rather than the amount of oil that needs to be removed. Smaller units can struggle to skim large surface areas effectively, meaning the unit will have to work longer and harder achieve intended results. This can also lead to maintenance issues and drops in overall skimmer productivity.

My skimmer is collecting too much water/coolant.

If your skimmer is picking up a lot of water, try evaluating how often you’re running the skimmer- when is oil visibly collecting? Skimmers should run only when oil is actually present, and running it when oil isn’t present increases the skimmer’s chances of collecting water. Setting the skimmer’s runtime with a timer or installing an Abanaki Oil Concentrator can help minimize water collection in the right applications.

Something else to consider is that the belt should be at least two feet away from any tank walls, and positioned so that the belt’s downstroke is aimed towards the bulk of oil present in the tank. The belt must also be long enough that the tail pulley is submerged in the fluid at all times.

Didn’t answer your question, or having a unique problem?

Please reach out to one of our industry expert reps at 440-543-7400 for a free phone conversation, or contact us at skimmers@abanaki.com. We also have an “Ask Skimmerman” Question Box available on our website that’s a great troubleshooting resource linked here for you. You can check us out on LinkedIn too, and our page is a homebase for all things oil skimming, available here.

Happy Skimming!