What is the difference between single and two stage air compressors?

Working principle two-stage screw air compressor

1. How many air compression stages can it be?

Generally, the working principle of air compression can be explained in two broad terms: positive displacement and dynamic displacement. The positive displacement refers to the air volume reduction to raise the air pressure.

Positive displacement & dynamic displacement air compressor

In terms of the positive displacement compressor, there are two types: single-stage air compression or two-stage air compression. The main difference between these two types of air compression is the number of times the air gets compressed: In a single-stage air compression, the air is compressed one time; in a two-stage compression, the air is compressed twice for double the pressure.

Single-Stage Screw air compressorTwo-Stage screw air compressor

As a professional air compressor manufacturer, Sollant offers both two types of air compressors. It’s worth mentioning that the Sollant Two-Stage Compression is been proved an efficient and cost-saving solution for air compression. The Two-Stage PM VSD Air Compressor is one of our star products and we’ll introduce you to how does a Two-Stage Air Compressor work.

Sollant PM VSD Two-stage Screw Air Compressor

2. How does the Two-Stage PM VSD Screw Air Compressor work?

The rotary screw air compressors use a pair of intermeshing screws (rotors) in a stator housing, with an inlet port on one end and a discharge port on the other end. Once these two rotors have “met” at the inlet port, the volume of air taken in becomes trapped between the flutes in the stator housing. Because of the helical pattern of the flutes on the rotors, the space between the screws is gradually reduced and the air is compressed.

Working principle two-stage screw air compressor

The Two-Stage Air Compressor contains two sets of these synchronized rotors, which can be housed in a common stator housing or two separate stator housings bolted together in tandem. And the intaken air goes through twice the air compression.


3. What’s the advantage of a Two-Stage Air Compressor?

The air compressors can be used in many applications, such as industrial, commercial applications or residential applications. For residential applications or applications below 90KW, the advantage of a Two-Stage Air Compressor isn’t very noticeable. However, when it comes to industrial applications such as manufacturing or repairing, the high efficiency, and energy saving that can be gleaned from the Two-Stage Air Compressor are impressive.

Inside of PM VSD Two-stage Screw Air Compressor

The main advantages of our PM VSD Two-stage Screw Air Compressor are the followings:

Our PM VSD Two-stage Screw Air Compressor operates at a slow speed splitting the pressure ratio into two stages. Thus, the Two-Stage Air Compressor reduces the bearing load and extends the compressor life significantly.

The PM VSD Two-stage Screw Air Compressor doubles the air pressure, increasing work efficiency and being much more reliable than the single-stage air compressor. That’s why our Two-Stage Screw Air Compressor is called Energy-Saving Two-Stage Air Compressor. Actually, our Two-Stage PM VSD Air Compressor saves energy up to 12%.

With a two-stage compression, there’s less moisture buildup in the tank and also a more extended period for the air to cool down in the tank. For this reason, the Two-Stage Air Compressor requires less maintenance.


4. How to choose the Two-Stage Air Compressor?

How to know whether to choose a single-stage air compressor or a two-stage air compressor? When choosing your compressor, besides the volume of air you need (CFM), you also need to determine how much pressure your application will require.

Sollant Tow-Stage PM VSD Air Compressor

Mostly you will need compressed air between 80-90 psi, but there are definitely applications requiring more: Generally, a single-stage air compressor will give you up to 135 psi with some as high as 150 psi while two-stage air compressors will produce up to 175 psi.

As a leading manufacturer in China’s industrial two-stage compression, Sollant offers you PM VSD Two-Stage Screw Air Compressor.

For more details, you can click: Energy-Saving Two-Stage Air Compressor