Kaishan USA | July 9, 2025 | Uncategorized
Bearings make a significant contribution to the performance and service life of an air compressor.
Bearings are one of the most critical elements in an air compressor, but especially in the airend of a rotary screw compressor.
They perform the following essential functions:
They achieve these results while the shafts are spinning at 3,000-6,000 revolutions per minute, with rotor tip speeds of 100-130 feet per second (30-40 meters per second). For oil-free compressors, the speed reaches 165-230 feet per second (50-70 meters per second), according to bearing manufacturer SKF.
Compressor manufacturers use several different types of bearings, using them in both the main motor and the airend. Some, maintaining the alignment of the rotors in the airend. Others, in the compressor’s motors.
There are many different types of bearings used in air compressors, including the following:
Various types of bearings are used in air compressors, including ball, roller, thrust and journal bearings.
Manufacturers of rotary screw compressors primarily use ball and roller bearings, whereas journal bearings are typically employed in reciprocating compressors to handle greater loads. Kaishan uses ball and roller bearings, and sometimes a combination of the two.
Kaishan uses premium SKF bearings in all its compressors, ensuring long life of the bearings and our compressors. It’s another example of our partnership with other U.S.-based suppliers to ensure all our components and parts are available with industry-leading lead times. No matter what you need, we have it in stock or nearby.
Longer bearing life is one of the advantages of a two-stage air compressor, such as our KRSP2 premium rotary screw air compressor.
Kaishan’s KRSP2 two-stage rotary screw air compressor is one of the most energy-efficient machines on the market, generating up to 15-20% more flow than a similarly sized single-stage compressor. And a payback in less than two to three years.
Two-stage compressors, such as the KRSP2, split the workload into two stages, resulting in less mechanical stress and lower heat, which reduces wear and tear and extends the life of air compressor bearings and other components. Because there are four discharge bearings on the first stage and three on the second stage, the bearings on the KRSP2 experience less stress than the two bearings that carry the entire thrust load in a single-stage unit.
As a result, two-stage compressors may be a solution for facilities experiencing frequent bearing failure. When equipped with a variable-speed drive, our KRSP2 is one of the only two-stage units available in sizes as low as 30 HP.
With lower forces and more air compressor bearings, the KRSP2 is built to last, enabling us to offer an industry-leading lifetime airend warranty.
Kaishan KRSP2 rotary screw air compressors have the best warranties in the industry. Our standard warranty covers the complete compressor package for 12 months from the date of startup (or 18 months after it’s shipped, whichever comes first), with an airend warranty of 24 months. With our extended warranties (provided at no additional cost), Kaishan’s KRSP and KRSP2 screw compressors are backed by a lifetime warranty on the airend.
An unmatched lifetime airend warranty backs Kaishan’s KRSP and KRSP2 screw compressors.
Because they don’t inject oil to cool and lubricate the airend, an oil-free compressor, such as Kaishan’s KROF oil-free rotary screw compressor, typically uses two stages to achieve the desired pressures. It runs faster and has special labyrinth seals to prevent bearing oil from entering the airend.
Key elements of bearing maintenance include controlling the environment and providing periodic lubrication.
First, you’ll want to avoid high levels of humidity, high temperatures and contaminants.
Second, because greasing intervals vary from machine to machine based on the motor size and type, make sure to follow your manufacturer’s recommendations for bearing lubrication. Kaishan uses the oil in the oil circuit to lubricate the bearings, sometimes adding an auxiliary oil pump (especially in oil-free variable-speed drive compressors and larger oil-flooded units). However, since the oil filter change interval is 2,000 hours, we encourage our customers to service all motors with a grease fitting on the drive and rear end at the same time.
It’s also wise to pay attention to excessive noise or vibration as part of your daily compressor operation. That may be an indication of bearing problems. Some companies even do vibration analysis as an additional preventive maintenance technique.
We encourage customers to monitor noise and vibration levels—often an early indication of a bearing problem—as part of their daily compressor operation. Some companies even do vibration analysis as an additional preventive maintenance technique.
The first indication of bearing trouble, however, often comes in an oil sampling report.
Fluid sampling can detect excessive bearing wear, allowing you to be proactive when you uncover a problem, even avoiding an unplanned shutdown. You should draw a fluid sample and have it analyzed every 2,000 hours (or twice a year, whichever comes first) to maintain warranty protection.
Most compressor manufacturers, including Kaishan, require oil sampling to maintain warranty eligibility.
If fine metal is detected in the sample, it indicates future bearing failure. Since the rotors never touch, you’ll only find metal in an oil sample if there is bearing failure.
Regular sampling will also indicate whether your compressor is exposed to excessive heat or is drawing in contaminants. Thus, it is critical to the life of an oil-flooded rotary screw air compressor, and most compressor manufacturers, including Kaishan, require it to maintain warranty eligibility.
Problems with air compressor bearings probably won’t fix themselves and will most likely lead to more extensive and expensive repairs. If you are experiencing issues with air compressor bearings, we’d strongly recommend that you work with your local compressed air professional to identify the cause.
That’s the kind of help you can get by working with our nationwide network of independent distributors. They can provide on-site assistance and consultation as needed.
We partner with these independent, local businesses because it's the best way to serve you. Unlike large corporate suppliers, there's no red tape; our distributors offer expert guidance, faster response times and personalized support tailored to your needs. They do much more than sell compressors—they build relationships, ensuring you get the right system, reliable service and quick access to parts when you need them most.
They have factory-trained technicians who have a deep understanding of industrial applications and can help maximize efficiency and minimize downtime. When you buy through Kaishan, you're getting more than a product—you're getting a local partner who cares about your business and wants to see it succeed.
Problems with the bearings in your rotary screw air compressor can have a significant impact on the operation of your compressed air system and all the processes that rely on that system. If you need help identifying the root of bearing problems, get in touch with the experts at Kaishan. Contact us today.
text
Kaishan Product Configurator | |||
---|---|---|---|
Model |
|
||
Drive |
|
||
Type |
|
||
Horsepower | |||
Pressure |
|
||
Flow (25-3000) | |||
Submit | |||
Models | |||
Enter your name and email to see the webinar | |||
---|---|---|---|
Full Name | |||
Submit |