Rotary Vane Vs Rotary Screw Compressors

Rotary Vane Vs Rotary Screw Compressors

Recognising and understanding the difference between a rotary vane compressor and a rotary screw compressor is something we get asked a lot at Control Gear, especially when you need to find the right air compressor suitable to your specific needs.

In reality, both the rotary vane compressor and rotary screw compressor manufacturers will tell you that what they have to offer is the best. However, even with a long history of excellent design and longevity, it is still important to understand the capabilities on offer with each option so that you can get the performance needed in your workplace.

As both rotary vane compressors and rotary screw compressors are great choices, knowing which one to pick depends a lot on the needs and workplace compatibility and taking the time to choose the right air compressor is essential when you want to get the best results every time.

We’ve shared everything you need to know about rotary vane air compressors and rotary screw air compressors so that you can make an informed decision that works for you.

Read on to find out more about how rotary screw and rotary vane compressors operate and learn which is the best for you!

Understanding Rotary Vane Compressors

A rotary vane compressor uses centrifugal force to create the required air pressure. Unlike other air compressors, vane compressors do not use reciprocating pistons and actually create a spinning technique that is used to get the air compressor working at high speeds for the best air solutions.

Vane compressors comprise a rotor and slots that house individual sliding vanes along the sides. This rotor turns within the cylinder wall, keeping all the parts neatly stored for easy use and simple maintenance.

Vane compressors are well known for offering better energy efficiency as time goes on purely because the rotor blades wear down and help to create better performance for your needs.

As the vanes rotate and work, the vane blades bear down into the stator bores and create a stator wall where the seal is near perfect. This virtually perfect seal works to avoid problems with air loss and offers up to a ten per cent improvement in energy efficiency.

However, this can be a problem as vane machines tend to have vanes that slide in and out, causing more significant wear and tear that could result in lower pressure and internal leakages that stop the machine from delivering what you need.

Choosing between vane and rotary screw compressors can feel complex, but the following list of benefits will help you understand precisely what a vane compressor can offer:

  • Rotary Vane is Simple to Operate
  • Choosing a Rotary Vane Air Compressor is Cost Effective
  • You Can Enjoy a Long Life from Your Vane Air Compressors
  • Vane Compressors are Easy to Maintain
  • A Rotary Vane Air Compressor is Small and Compact
  • Vane Compressors are Energy Efficient
  • The Centrifugal Force Ensures Great Speed Control

With so many great benefits on offer, rotary vane air compressors could be the right choice for you!

Understanding Rotary Screw Compressors

If rotary vane compressors don’t seem right for you, then rotary screw air compressors could be a better choice. Screw compressors work with the use of rotary movements, creating the air compressor results you need.

The design of the rotary screw air compressors is pretty straightforward, with male and female parallel rotors. When the rotor turns, the screw counterparts get to work trapping air that can then be used for your compressed air needs.

One of the great things about screw compressors is that they do not need to be worn in before they can provide the most volumetric efficiency, ensuring that you get 100% from day one. They also perform better when it comes to turndown rates, energy efficiency and speed control and range.

As screw compressors have evolved, oil free screw compressors have been designed to support use in applications such as food or other sensitive materials.

In addition, screw compressor manufacturers have designed solutions that operate efficiently from 15 – 100% load without energy loss, making screw rotors a logical choice.

Choosing a screw compressor also comes with a number of benefits that include:

  • Energy-Efficient Usage with Each Screw Compressor
  • Screw Compressors Run with a Larger Capacity
  • Screw Compressors Have Two Parallel Rotors for Volumetric Efficiency
  • A Screw Compressor has a 100% Duty Cycle
  • Screw Air Compressor Lasts the Test of Time

Whether you are looking for a way to avoid trapped air or need an air compressor that can work at low speeds, screw compressed air is a popular choice.

A Comparative Analysis of Rotary Vane Vs Rotary Screw Compressors

Whether you are thinking about how to keep the rotor vane slot working the right way or you want to understand how direct drive coupling works, making your decision can be difficult when you don’t have a side-by-side comparison.

We’ve shared a comparative analysis of both options in four key areas; energy efficiency, performance, longevity & maintenance and operating speeds.

Energy Efficient Solutions

If the most critical factor in your decision is your energy consumption, then the rotary vane air compressor is possibly the best choice. This is because they have minimal internal air leakage paths, ensuring that all the air you use is directed correctly, saving you money and ensuring the most efficient solution.

This does not mean that the screw counterparts are not energy efficient, just that they are not as efficient as the vane solution. In reality, if your industry needs rotary screw air compressors, you will find that they will produce efficiently compressed air, but when there are leaks, the compression equals lost energy that could increase your energy bills until it is fixed.

Getting the Best Performance

Another key consideration when you are buying a new air compressor is how well your chosen model will perform when put to the test. The good news is that both options run continuously, which is ideal when using them in an industrial environment.

If you are looking for a model that can kick into 100% action from the start, then the rotary screw air compressors offer this, while the rotary vane compressors take time to bed in and get to 100% as the individual sliding vanes wear down into the optimal position.

Longevity & Maintenance Needs

To get the best value for money, it’s essential to find an air compressor that will last for as long as possible and require as little maintenance as possible. With this in mind, the rotary vane air compressor boasts an unlimited operating life as long as it is well maintained.

The rotary screw air compressors can run for 20,000 hours as long as there are replaceable roller bearings fitted to ensure consistent running. There are some critical areas that need to be maintained for the best running, including the air inlet, internal surface and other items specific to the mode you choose, such as the modulating control, rotor slots and more.

Operating Speeds for Compressors

The final consideration that’s important before you buy is the operating speeds on offer compared to the air compressor operating speeds you need. Rotary vane compressors work at a lower speed, providing lower power consumption, and rotary screw compressors run at higher speeds but cost more to run.

The reason why rotary screw compressors have to run at a higher speed is because lower speed compression equals lost energy and so a higher speed is required to counteract it. Bear in mind that with this higher speed comes less energy efficiency.

Vane Machines & Screw Compressors Summary

With all the information shared, picking the right compressed air compressor can feel like a difficult decision, especially when you need something that is right for your specific needs and circumstances.

To help, we’ve shared a quick summary of the pros and cons of each compressor:

Rotary Vane Compressors Pros

  • It offers a great suction vacuum when in use
  • It offers a good continuous air compressor supply
  • Long life expectancy
  • Great for moderate pressure
  • The air seal is near perfect
  • Low air leakage problems
  • Great for agriculture, automotive, welding and dry cleaning industries

Rotary Vane Compressor Cons

  • Potential for excessive vibration in the cylindrical housing
  • Maintenance can be expensive as there are lots of moving parts
  • Needs to wear in before producing the best outcomes

Rotary Screw Compressor Pros

  • Hard wearing and long lasting
  • Many options offer quiet operation
  • Can meet high workload demands
  • Energy efficiency when being used
  • Provides clean air for a wide range of uses
  • Great for industrial, manufacturing, automotive and food industries

Rotary Screw Compressor Cons

  • Can be high in cost and maintenance including roller bearings being replaced
  • A complex system that can be difficult to maintain without expert support
  • Can experience problems with ensuring no internal air leakage paths

Let Control Gear Support Your Compressed Air Needs

At Control Gear, we make it our mission to support you when looking for the best way to get delivered air for all your applications as well as helping you to find the best solutions to compressed air problems.

Contact our team of experts for more personalised advice on choosing the right compressor for your business.