Lubricated VS Oil-Free
Anyone who has ever looked at our product catalogue or our website may have seen the terms: lubricated and oil-free. But what is it and when do you use which option?
Inside pneumatic motors, moving parts are hard at work and these parts simply need lubrication to keep wear low and therefore longevity high. That is why many motors, including pneumatic motors, are lubricated with oil. Oil ensures sealing and minimizes friction between moving parts, limiting wear and thus improving service life. Lubricated motors are therefore always the easiest and best option for an optimal lifespan. For some applications however, the use of oil is absolutely not permitted.
The solution to oil-free operation
For hygienic applications, such as the food industry, regulations often do not allow used machines to use oil. This is due to the risk of contamination of the end product. Using special “food graded oil” can be one of the options for these applications. For other applications however, the end product can not come into contact with any oil at all, because it can affect the quality or operation of the end product. This is the case when mixing emulsions for instance.
These applications therefore require drives without lubrication, but the omission of lubrication directly affects the wear, reliability and lifespan of a motor. Oil-free pneumatic motors have been developed especially for these challenges. These motors are designed to have the longest possible reliable lifespan in an oil-free application.
Our GLOBE vane motors are available in a lubricated or oil-free variant, the non lubricated variant enjoys the same advantages as its lubricated brother: all motors are ATEX certified, they can be overloaded or blocked for a long time without damage and they are instantly reversible. In addition, oil-free motors are easier to maintain (there is no in-line lubrication system to replenish) and the emissions are cleaner because there is no oil mist from the air exhaust. But what about the lifespan?
Because the non lubricated vane motors do not use oil, the vanes will wear out faster. That is why the GLOBE Oil-Free Vane Motors use special vanes made of a low friction material to ensure optimal service life, despite the fact that there is no oil in the motor.
These motors are designed to have the longest possible reliable lifespan in an oil-free application.
However, an non lubricated vane motor runs at lower speeds than a lubricated vane motor, purely due to the fact that there is no lubrication in the motor. Lower speed also means less power. This power loss is approximately 20%, but because vane motors are already extremely powerful on their own (more powerful than an electric motor of the same size), this often does not cause any disadvantages. In the end are lubricated motors simply unacceptable for some applications, so it is nice that there are non lubricated variants available that have a long lifespan and reliability.
How to choose the best oil-free air motor
GLOBE does not only have vane motors in its oil-free motor portfolio, our compact piston motors are also lubrication free (standard!). Due to the unique design, the pistons can achieve a long service life and high reliability without the use of oil. In addition, air consumption is low and torque is high. But how do you know which of these two air motors to go for, if you have an oil-free application?
Vane motors are known for a (relatively) high power, torque and available speed compared to their size. Compact piston motors inherently have a relatively high torque in combination with a low speed. As a result, you will never actually use non lubricated vane motors for the same applications as a compact piston motor.
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Prevent a 'cake batter on the ceiling' effect
For example, take an industrial mixer. The mixed emulsion should not come into contact with oil because it can change the composition, so an oil-free motor is necessary, but should we choose an oil-free vane motor or a compact piston motor? Then we should look at the torque, speed and power that is needed here.
A mixer uses (relatively) low speeds, a speed that is too high gives the same effect as mixing cake batter at too high a setting: a lot of ceiling cleaning. In addition, a high torque is desirable because the mixer has to plow through an emulsion. If you choose an non lubricated vane motor in this situation, you will have to combine it with a huge gearbox to reduce the speed and maintain the desired torque, and that is not the most efficient (or space-saving) solution.
A speed that is too high gives the same effect as mixing cake batter at too high a setting: a lot of ceiling cleaning.
Instead, you choose the compact piston motor, which already has this low speed (to prevent dirty ceilings), and a high torque at the same time to keep the mixer moving. If you have an non lubricated application that benefits from higher speeds or more power, for example a hoist or crane in a commercial kitchen, then the non lubricated vane motor is the best choice. With their maximum power of 9.5 kW or 12.7 HP, the power range of a GLOBE Oil-Free Vane Motor is simply greater than their little brother, the compact piston motor.
Oil-free vane motors and compact piston motors both have their unique properties, so you never have to choose between these two motors. Depending on your application and the power/torque required, one of these non lubricated motors is your perfect match. Our specialists are happy to help you with this matchmaking, so that you will soon have the perfect (oil-free) air motor for your application. Contact us today!
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Great blog post! Understanding the differences between lubricated and oil-free pneumatic motors is crucial for optimizing performance in various industries. Excited to learn more about their applications!