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Which is better piston or rotary compressor?

Author:
15 Mar 2024

The use of air compressors is more common than you might think. Chances are, you’ve encountered more than one type of air compressor in different environments and you just didn’t know it at the time. For instance, the closest air compressor to you may be the one hidden in your refrigerator, and you may have used another when you stopped at a gas station to inflate your car’s tires.

Air compressors are versatile machines with various applications for maintenance and leisure whether at home or in businesses including but not limited to automotive body shops, construction, food and beverage, healthcare, and agriculture. 

The primary function of air compressors is to convert low-pressure gas into high-pressure gas for efficient use. Compressed air is vital to power pneumatic tools and machines such as pumps, pressure washers, paint sprayers, nail guns, and the like. Air compressors are also at work on an industrial scale in manufacturing processes and HVAC ventilation systems.

Air compressors are not a one-size fits all machine. They range in size and power supply to suit specific jobs and conditions but are mainly categorized as reciprocating piston air compressors or rotary screw air compressors. 

Understanding Piston/ Reciprocating Air Compressors

Piston also referred to as reciprocating air compressors utilize continually moving parts to produce compressed air and are designed for intermittent use. As its name suggests, it involves the reciprocating motion of pistons traveling forward and backward inside its cylinder. 

There are two types of reciprocating air compressors. It can either be a single-stage or two-stage piston air compressor. Basically, it differs in the number of times the air is compressed and the size of the pistons per stage. You can further distinguish them based on the dimensions of its cylinders and how many air intake valves it has. 

Single-stage reciprocating air compressors have identically sized cylinders with their respective air intake valves. On the other hand, two-stage reciprocating air compressors would have significantly larger cylinders with only one air intake valve linked by a cooling tube that lowers the air’s temperature before it goes through another round of compression with a smaller piston. 

The choice between getting a single-stage or two-stage reciprocating air compressor would depend on the air pressure and quality you need to achieve.

Piston air compressors are recommended when you only need short bursts of compressed air. It is commonly used at home, garages, and workshops for the following applications:

  • inflating tires
  • airbrushing
  • sandblasting
  • wood/ metalwork
  • pneumatic machines for cleaning

Exploring Rotary Compressors

Screw or rotary compressors use two helical screws, also called rotors, and are made to run nonstop. Compressed air is generated when air is trapped in between the male and female screws that are spinning in opposite directions at fixed speeds. 

Built with an internal cooling system, you can rely on a 100% duty cycle without worrying so much about your unit overheating. You’re actually more at risk of damaging rotary air compressors when you do not use them to their full capacity.

The main advantage rotary air compressors have over their piston counterparts is that they have fewer wearable components. For example, direct-drive air compressors are a kind of screw compressor that have fewer moving parts since the motor connects straight to the compressor pump. 

Rotary air compressor machines are widely used in industries that require a constant supply of clean and compressed air including:

  • food processing and packaging
  • robotic and high-volume manufacturing
  • paint production lines
  • conveyor systems 
  • hospitals

Rotary vs. Reciprocating Compressor

Below is an efficiency and performance comparison to help you assess whether rotary or reciprocating compressor is best for your needs.

Power Consumption

Piston or reciprocating air compressors can be more inexpensive to operate since you’re using it on and off or short increments of time throughout the day. However,  it is more ideal to have a rotary air compressor when you require a continuous flow of highly pressurized air.

Maintenance and Durability

Piston air compressors have more moving parts that need to be regularly maintained. You’d have to be vigilant about changing its inlet air filters and oil unless you have an oil-free air compressor. You also need to check the belt’s tension if you have a belt-driven piston air compressor and see if it needs to be adjusted or replaced.

Rotary air compressors have fewer parts that need to be maintained but need to be serviced by a skilled technician every 1,000 – 2,000 hours.

In terms of longevity, piston air compressors can last around 50,000 hours before needing to be replaced while rotary air compressors can go over 100,000 hours.

Noise and Vibration

With more moving parts, piston air compressors can be expected to be noisy which is why they are usually situated in open spaces or in a separate room. Piston rings are also always in contact with the cylinder walls so these types of air compressors also tend to vibrate and pulsate.

Rotary screw air compressors generally boast a smooth and quiet operation with minimal vibration. Since the screws are not in contact with each other,  you don’t have to think about abrasions to the cylinder or pulsations. 

Size and Portability

Since piston air compressors tend to vibrate and pulsate, they need more space and more stable ground. They also generate more heat internally so where you put them will have an immediate effect on its air quality and compressor life. For these reasons, rotary air compressors offer more flexibility in terms of placement. However, it is always best to have air compressors situated in well-ventilated areas.

The portability of both types of air compressors will greatly depend on the size of the tank and the power supply required. If you need an air compressor you can take anywhere for basic pneumatic tools and machines, then a mini DIY oil-free air compressor may be enough to handle the job.

Cost Considerations

Piston air compressors are typically more affordable upfront but require more frequent maintenance checks and changes. On the other hand, rotary air compressors have a higher initial investment with a more advanced design but can be more practical for long-term and nonstop use. Rotary air compressors also have fewer parts that need maintenance, you may just need to spend on having it serviced by a skilled technician once in a while.

Conclusion

Both piston and rotary air compressors have their pros and cons. Not one type of air compressor is absolutely better than the other. It would always come down to the application and environment you’re in. You’d also have to factor in the initial cost as well as the cost of operations.

If you’re looking for a reputable air compressor supplier in Singapore, you can trust that Lian Beng delivers top-notch quality air compressors and their parts. They’re also a distributor of monster air compressors.