Return of the screw

21 November, 2018

 Longevity

Take longevity, for example. One potential benefit of the vane design is that the shaft experiences small radial loads. Compressors of this design can support their shafts with simple plain bearings that usually last the lifetime of the machine. That doesn’t mean vane compressors are maintenance free, however. Compressors are long-lived, hardworking machines and all designs require parts such as seals to be replaced periodically. What matters more is how easy that work is to do, how often it is required, and how much it costs. And that is down to the details of individual compressor design and manufacture, regardless of type.

Efficiency

Then there’s efficiency. Manufacturer efficiency claims are often based on the operation of machines at a single carefully selected speed. Every model has an operational sweet spot where it works at its best. The end user needs to understand the efficiency that will be delivered by the system in their application under real-world operating conditions. That’s going to depend on a host of factors, including whether a particular manufacturer has a model that provides a close match, and how the whole compressed air installation is designed and operated.

In summary, in the choice between vane and screw compressors, your application might determine the answer for you. If you need high pressures or oil free air, you need a screw design. Where either technology could do the job, it’s time to worry less about the fundamentals and more about the details of the particular machine, the overall compressed air installation and, of course, the support and experience of your supplier.

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