What Is The Compressor Air End And How to Choose?

The compressor air end of a screw compressor is a vital component responsible for compressing and delivering air to various applications.

Understanding the air end and choosing the right one for your needs can ensure the efficiency and reliability of your compressor.

In this article, we will discuss what an air compressor air end is and how to choose the right one for your air compressors.

Whether you’re a seasoned professional or new to the industry, this article will provide you with valuable insights into the air end of a screw compressor and help you make informed decisions when selecting one.

What is The Compressor Air End?

The air end is the heart of a rotary screw compressor. It is responsible for compressing the air and delivering it to the rest of the compressed air system. And an air end determines the compressor’s performance, efficiency, and energy consumption.

The air end consists of two rotors, a male and a female, that are meshed together and rotate in opposite directions.

As the rotors turn, the air is drawn into the compressor and compressed between the rotors. The compressed air is then discharged into the system at a high pressure.

How Does the Compressor Air End Work?

As mentioned, the air end consists of two rotors, a male and a female, that are meshed together and rotate in opposite directions.

The male rotor has four lobes, while the female rotor has six. The two rotors are separated by a small clearance, known as the working gap.

As the rotors turn, the lobes on the male rotor engage with the spaces between the lobes on the female rotor, creating a series of air pockets that are progressively compressed as they move along the rotors. The compressed air is then discharged into the system at a high pressure.

Types of Air Compressor’s Air End

There are two main types of air compressor air ends: oil-injected and oil-free.

Oil-injected air ends require oil to lubricate the rotors and bearings and to cool the compressed air. This type of air end is more commonly used in industrial applications where high volumes of compressed air are required.

Oil-free air ends do not require oil and are more commonly used in applications where oil contamination is a concern, such as food and beverage, pharmaceuticals, and electronics. This type of air compressor is called oil-free air compressor.

The Importance of Air End Efficiency in Compressor Selection

It is important to consider the efficiency of the air end in compressor selection.

Why Is Air End Efficiency Important?

Air end efficiency directly affects the compressor’s performance, energy consumption, and operating costs.

A more efficient air end will produce more compressed air while using less energy, reducing operating costs and improving the overall performance of the compressor.

In contrast, a less efficient air end will require more energy to produce the same amount of compressed air, resulting in higher operating costs and reduced performance.

How to Measure Air End Efficiency?

Air end efficiency is measured by its specific power, which is the amount of power required to produce one cubic meter of compressed air per minute (m3/min).

The lower the specific power, the more efficient the air end. It is essential to consider the specific power when selecting a compressor, as it directly affects the operating costs.

Factors Affecting Air End Efficiency

Several factors affect air end efficiency, including the design, quality, and maintenance.

The design of the air end, such as the rotor profile, clearance, and orientation, directly affects its efficiency.

High-quality air ends with tighter tolerances and better materials also contribute to higher efficiency.

Proper maintenance, including regular cleaning, lubrication, and replacement of worn components, is also crucial to maintaining the air end’s efficiency.

Why Choose an Efficient Compressor Air End?

Choosing an efficient air end can lead to significant energy savings and reduced operating costs.

It also ensures that the compressor can meet the required air demand while maintaining its performance and reliability.

In addition, an efficient air end reduces the environmental impact of the compressor, as it consumes less energy and produces fewer emissions.

How to Choose the Compressor Air End Correctly?

It is important to choose a compressor air end design that is efficient, durable, easy to maintain, flexible, noise-reducing, and manufactured to the highest standards of quality.

Here are some key features to look for in air end design for screw compressors:


One of the most important features to look for in an air end design is efficiency. An efficient air end design can help reduce energy costs and increase productivity.

Look for an air end design that uses advanced technology and materials to improve efficiency.


The compressor air end is exposed to high temperatures, pressure, and wear and tear. Therefore, it is important to choose an air end design that is durable and can withstand the demands of the application.

Low maintenance

Maintenance is an essential part of ensuring the longevity and efficiency of a screw compressor.

A great air end design should be easy to maintain and requires minimal downtime for maintenance.


Different applications require different levels of air pressure and flow.

Choose an air end design that offers flexibility in terms of pressure and flow rates. This will allow you to tailor the compressor to meet your specific needs.

Noise reduction

If your screw compressors are be noisy, which can be a significant problem in certain applications.

An air end that includes noise-reducing features will resolve this problem. Such as a sound-insulated enclosure or a low-noise intake system.

Air End Maintenance Tips for Longer Compressor Lifespan

Air compressors are designed to last for a long time, but it requires proper maintenance to ensure their longevity. In this section, we will discuss some air end maintenance tips that can help prolong the lifespan of your compressor.

Regular Cleaning and Inspection

One of the critical aspects of air end maintenance is regular cleaning and inspection. The air end should be kept clean from any dirt, dust, and debris that could accumulate on the surface.

The accumulation of these particles can cause blockages and reduce the efficiency of the air end. Inspecting the air end regularly can help detect any wear and tear and address it promptly to avoid further damage.

Maintain Proper Oil Levels

The air end requires lubrication to prevent wear and tear on its moving components. Therefore, it is essential to maintain the proper oil levels in the compressor.

Check the oil levels regularly and refill if necessary. Ensure that the oil used is of high quality and is compatible with the air compressor’s design.

Monitor and Address Vibration Issues

The air end’s rotating components can produce vibration that can damage the compressor if left unaddressed.

Therefore, it is crucial to monitor the compressor’s vibration levels and address any issues promptly. The compressor should be mounted on a stable surface and aligned correctly to reduce vibration.

Replace Worn-Out Parts

The compressor air end has several components that are subject to wear and tear due to the compressor’s constant operation.

It is essential to replace these parts regularly to avoid further damage, include seals, bearings, and gaskets.

Follow Proper Maintenance Schedule

All air compressor manufacturers provide a maintenance schedule that should be followed to ensure the compressor’s longevity.

The maintenance schedule includes tasks such as changing filters, cleaning, and inspecting the air end, and changing the oil. Following the proper maintenance schedule can help prevent major repairs and prolong the compressor’s lifespan.

Regular maintenance can also help reduce energy costs and improve the compressor’s efficiency, resulting in cost savings for your business.

How to Troubleshoot Common Compressor Air End Problems

Rotary screw air compressors are essential tools in various industries, and they are expected to run smoothly and efficiently. However, even the best-maintained compressors can develop issues with their air end.

So, we’ll discuss some common air end problems in air compressors and how to troubleshoot them.

Low Discharge Pressure

If you notice that the air compressor is producing low discharge pressure, this could indicate that there’s a problem with the air end.

Check the inlet filter, oil filter, and oil separator for clogs, and replace them if necessary.

Also, inspect the air end for any damage or worn parts, such as bearings or rotors, and replace them as needed.

Additionally, make sure that the compressor’s V-belts are in good condition and tightened properly.

High Discharge Temperature

A high discharge temperature can cause the air compressor to shut down, so it’s crucial to address this issue promptly.

Inspect the cooling system, including the fan, radiators, and oil cooler, for any damage or clogs. Clean or replace any dirty or damaged components.

Make sure that the compressor is properly lubricated, and that the oil level and quality are within the manufacturer’s recommended specifications.

Excessive Noise or Vibration

Excessive noise or vibration can indicate a problem with the compressor air end, such as worn or damaged bearings, rotors, or seals.

Besides, you should check the alignment of the air end, motor, and compressor assembly. Make sure that the compressor is mounted on a solid foundation and that it’s not overloaded or running beyond its capacity.

Oil Carryover

Oil carryover is a common problem in air compressors, and it can lead to contamination of the compressed air system. Check the oil separator and replace it if necessary.

Additionally, make sure that the compressor’s oil level is within the recommended range. And ensure the oil quality are within the manufacturer’s recommended specifications.

Poor Efficiency

If the compressor is operating inefficiently, this could indicate a problem with the air end.

First step, check the inlet filter, oil filter, and oil separator for clogs.

The second step, inspect the air end for any worn or damaged components, such as bearings or rotors, and replace them as needed.

In conclusion, compressor air end problems can cause serious issues with compressors, but many of these issues can be prevented with proper maintenance and troubleshooting.

By following the tips outlined in this section, you can keep your compressor running smoothly and efficiently, ensuring maximum productivity and lifespan.

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