Reciprocating and Rotary Compressor: What’s the Difference
Do you want to buy a new air compressor but are unsure whether to choose a reciprocating or rotary screw model?
While both are positive displacement air compressors and serve the same purpose, they differ in their operation and the types of applications they are best suited for.
In this blog post, we will compare reciprocating and rotary screw compressors, highlighting the pros and cons of each type. We will also help you determine which compressor best fits your facility and operation.
Let’s get started.
What Is a Reciprocating Air Compressor?
A reciprocating compressor, also known as a piston compressor, is an air compressor that uses pistons driven by a crankshaft to compress air. The pistons move back and forth in a cylinder, compressing the air as they move toward the cylinder head. The compressed air is then stored in a receiver tank, ready for use.
The use of pistons for air compression can be traced back to the mid-1600s. Since then, there have been minimal changes in the design and mechanism of the reciprocating air compressors.
What is a Rotary Screw Compressor?
Rotary screw compressors, also known as rotary air compressors, are a type of air compressors that uses two meshing helical screws, called rotors, to compress the air. The rotors, interlocking spirals, turn and force the air through the chambers, compressing it into a smaller space. The compressed air is continuously created as the rotors keep turning. The compressed air is then stored in a receiver tank ready for use. The design of rotary screw compressors has not changed much since their inception in the mid-1900s. The basic concept of using two meshing rotors to compress air has remained the same. However, advances in manufacturing and materials have improved the efficiency and durability of these compressors. Moreover, electronic controls and automation have made them easier to manage and maintain. Some of the rotary screw compressors now come with variable speed drive, which allows them to adjust the airflow according to the demand leading to energy savings.
Reciprocating and Rotary Compressor: What’s the Difference?
There are several critical differences between rotary screw compressors and reciprocating compressors:
Design:
Rotary screw compressors use two meshing helical screws (rotors) to compress the air, while reciprocating compressors use pistons driven by a crankshaft.
Efficiency:
Rotary screw compressors are generally more efficient in electricity consumption and cost than reciprocating compressors. They use two meshing helical screws to compress the air, which results in a more continuous flow of compressed air and less energy loss compared to the piston movement in reciprocating compressors.
However, rotary screw air compressors have a higher initial cost as they are more complex and use more advanced technology than reciprocating compressors.
Noise level:
Rotary screw compressors are known for their quiet operation, in contrast to reciprocating compressors which tend to be louder due to the movement of the pistons. The noise level of a rotary screw compressor typically ranges between 70-80 dB(A), while a reciprocating compressor can produce noise levels of around 80-90 dB(A), depending on the size, model, and brand.
However, it's worth noting that with advancements in technology, some reciprocating compressors now come equipped with noise reduction features which can effectively reduce their noise levels.
Maintenance:
Maintenance of compressors are an important while making your choices. Rotary screw air compressors are generally easier to maintain than reciprocating compressors. They have fewer moving parts, which results in less wear and tear and fewer potential points of failure. Moreover, the lack of piston rings in rotary screw compressors means there is less need for regular oil changes and less potential for oil leaks.
Despite being less easy to maintain, reciprocating is still a popular choice amongst several businesses because of its low initial cost and compact design.
Airflow:
A rotary screw air compressor is known for its smooth and consistent airflow compared to a reciprocating air compressor. The two meshing helical screws in a rotary screw compressor compress the air in a continuous manner, leading to a steady stream of compressed air. On the other hand, a reciprocating compressor relies on the movement of a piston to compress the air, which can cause pulsations and fluctuations in the airflow, especially at higher pressures.
Air pressure:
The type of air compressors selected can greatly impact pressure output. Both rotary screw and reciprocating compressors have distinct capabilities.
Rotary screw compressors are optimized to consistently produce compressed air at a specific pressure, usually up to 150 psi (10.3 bar), making them ideal for situations such as operating pneumatic tools.
On the other hand, reciprocating compressors are designed to generate compressed air at higher pressures, frequently reaching up to 200 psi (13.8 bar) or more, and are well suited for high-pressure air applications like industrial processes and spray painting. Also, the pressure generated by reciprocating compressors can vary as the piston moves, resulting in pulsations and changes in air pressure.
Size:
Rotary screw air compressors are larger and bulkier than reciprocating air compressors. Since they deal with a larger volume of air, they have large motors attached to them which take up more floor space, sometimes even a separate room.
On the other hand, reciprocating air compressors are small. Their compact design makes it easy to install them in tight spaces or areas with limited floor space.
Ultimately, the choice between a rotary screw compressor and a reciprocating compressor will depend on the application's specific needs, such as how much compressed air is needed, the operating conditions, and the budget.
Reciprocating and Rotary Compressor: Which One Should I Choose?
Rotary screw compressors and reciprocating compressors are suitable for different applications and industries.
Rotary screw compressors are most ideal for applications that require a constant flow of compressed air at a consistent pressure level. They are typically used in industries that require a large volume of compressed air, such as manufacturing, construction, oil and gas, food and beverage, pharmaceuticals, textile, automotive, and power generation.
On the other hand, reciprocating compressors are suitable for applications requiring high-pressure air or a low flow rate. They are typically used in automotive, construction, manufacturing, , and HVAC.
Reliable Reciprocating and Rotary Compressor Manufacturer - Atlas Copco
Atlas Copco is a global industrial air compressor manufacturer and supplier with operations in more than 180 countries. It offers reliable reciprocating and rotary industrial air compressors that increase efficiency and uptime.
Need more guidance in choosing between a rotary and reciprocating compressor? Contact us for a free consultation - +971 4373 8216