Choosing the right type of compressor can make or break the efficiency, reliability and profitability of your operation. Choosing the right gas compressor for your specific needs is key. Two of the most common options—screw compressors and reciprocating compressors—each have their advantages but understanding the differences is critical to making the right decision.
At Kingsly Compression, we specialise in engineering solutions that maximise uptime and reduce maintenance headaches. Here’s your expert guide to screw compressors vs reciprocating compressors—and how to choose the right one for your needs.
What Are Screw Compressors?
Screw compressors use two screws, or intermeshing rotors, to compress gas or air. They are known for their ability to deliver high flow rates at low suction pressures. Compared to reciprocating compressors, they are simple, and incredibly reliable, with significantly fewer moving parts.
How Screw Compressors Work
The interlocking spirals in a screw compressor mesh together precisely, reducing the volume of trapped air or gas as it moves along the rotor length. As volume decreases, pressure increases, resulting in efficient compression with minimal losses. The design also allows screw compressors to operate for extended periods with little to no pulsation, reducing stress on the system.
Recommended Applications for Screw Compressors
Screw compressors are ideal for low suction pressures, from a slight vacuum to a few PSIG of positive pressure. This makes them explicitly well suited for Vapor Recovery, and are our most common Vapor Recovery Units (VRUs). While centrifugal compressors can be used up to a around 30 PSIG discharge, screw compressors can reliably go all the way up to 350 PSIG at the top end. Although rare, there are even some two stage compressors that will exceed 500 PSIG! Screw compressors will also have the highest flow rates per dollar, at the cost of sometimes utilizing more power than its reciprocating counterpart.
What Are Reciprocating Compressors?
Reciprocating compressors, also known as piston compressors, use a piston within a cylinder to compress gas. This is one of the oldest and most well understood compression methods but comes with its own set of pros and cons.
How Reciprocating Compressors Work
Just like a car engine, a reciprocating compressor pulls gas into a cylinder, compresses it with a piston, and then discharges the gas. Unlike a car engine, it doesn’t ignite it, and being at lower rpm’s, often utilize sprung plate or reed valves instead of poppet valves. These are significantly more resistant to unforeseen issues such as debris, and last a long time with great sealing properties. Compared to screw compressors, they are more efficient, and can be sized to just about any pressure required. They are, however, more complex with more moving parts.
Recommended Applications for Reciprocating Compressors
Common reciprocating compressor pressures start at a few PSIG of positive pressure, all the way up to thousands of PSIG used in Compressed Natural Gas (CNG) vessels. Negative pressures risk pulling air into the case through the vent, so extra engineering is required to mitigate that, and low pressures (Below 30 PSIG) need very large cylinders to flow enough pressure. The ideal suction pressures for reciprocating compressors start above 50 PSIG suction pressures, where screw compressors would be substantially overloaded, all the way up to thousands of PSIG. The other time when reciprocating compressors are mandatory is when discharge pressures exceed around 250 PSIG. While screw compressors can sometimes go above 200 PSIG, they tend to lose efficiency and utilize a lot of horsepower. Reciprocating compressors can provide efficient compression at significantly higher pressures than screw compressors could possibly hope to achieve.
Which Type does Kingsly Recommend?
Our engineers at Kingsly Compression take all factors into account when quoting a job. If you are moving less than 100 MCFD at relatively low pressures, you will likely be quoted a small reciprocating compressor from commonly known brands such as Quincy or Blackmer. If you want to flow a little more at these lower pressures, maybe 100 MCFD to 2000 MCFD, you can expect to see a screw compressor from a reputable brand like LeROI. And if your pressures are too high, either in suction or discharge, you can be sure we will quote a reciprocating compressor, such as Ariel, CiP, or Gardner Denver.
With Kingsly Compression you get a solution designed to maximise uptime, minimise operational costs and deliver sustainable value over the life of your equipment. We have short delivery lead times, and have an extensive stock of many of the compressors mentioned above.
Don’t leave your productivity to chance. Contact Kingsly Compression today for a custom consultation and see how our expertly engineered compressor packages can power your operation to new heights.