1. How large is your demand?
Rotary screw air compressors are especially durable and are able to handle large amounts of demand for extended periods of time. They are still more efficient and durable in smaller horse powers than piston compressors, but this is noticeable when getting into larger demands (i.e. 15 horsepower and more). Rotary screw air compressors are designed to run at 100% duty cycle, day in and day out.
2. Is lifetime cost important to you?
While yes, a rotary screw compressor may have higher air compressor maintenance cost and/or initial capital cost, the lifetime expectancy is much greater than a piston type compressor. Piston type compressors typically last about 10,000 hours before a rebuild is necessary. On the other hand, a rotary screw compressor will last between 60,000 – 80,000 hours. Rotary screw compressors are known for their reliability and longevity.
3. Does your machine operate near your production staff?
Rotary screw air compressors are known for their quiet operation. Being that most rotary screw air compressors come standard with low sound enclosures, they generally operate between 65 – 75 dBA, which is much lower in comparison to other types of compressors, especially piston, which can operate at around 80 – 85 dBA.
4. What do you want to feed your filtration?
Rotary type compressors are designed to have no more that 3 PPM of oil carry-over, while piston compressors can have 10 PPM or more as they age. Less oil carryover means that you have to change your filter elements less often, therefore decreasing that part of maintenance costs.
5. Do you use your compressed air continuously through the day? Or does your demand vary through the day?
- Rotary compressors have become more and more popular because of their efficiency and their ability to keep up with constant high demand. Many rotary screw compressors are used 24/7, and are the workhorses of many manufacturers.
- Even if you don’t have constant demand, rotary screw reliability and durability comes in a variable speed drive version. This will speed up and slow down in relation to your demand at that given point. This option should definitely be considered if your demand varies, because yesterday’s controls including on line/off line, modulation, and even turn valves have proven costly when compared to the benefits of the VSD.
All in all, rotary screw compressors today have become popular because of their efficiency, noise level, and that fact that the cost for a this type of compressor has dropped significantly in the last 10 years. They have low oil carryover and are durable and reliable. They come in VSD for applications with varying demands throughout the day. Rotary screw compressors are a worthwhile investment for any manufacturer looking for a good quality, overall cost-effective unit.