Difference Between Single-stage and Multi-stage Compressor

A compressor is a device that is most commonly found in every utility used in an industry. A utility refers to the thing that is required to aid every process in a plant like water, air, or steam.

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Compressors have advanced as time passed and engineering marvels have made this equipment more efficient to use. It is not known to many that there are multistage compressors available apart from single-stage ones. Mostly, everyone has heard about single-stage compressors.

What is a Compressor?

A compressor, as the name implies, compresses a medium like water or air by lowering its volume from high to low and thus increasing the pressure.

In simple terms, suppose you are standing on a crowded platform and a train has arrived. The train cannot accommodate the whole platform crowd, so the people will try to get on the train as fast as possible. The volume is high but the area is low, which will create a high pressure for the people who got inside the train, as it will be fully packed. This same logic works in a compressor.

A compressor reduces the volume media and, in that case, the pressure increases automatically. So, when the media comes out finally, it will be in full force. It will be the same where the people in the train will try to push each other and get themselves out first in full force, as compared to a relatively empty train where rush will be lower and people will come out comfortably.

Difference Between Single-stage and Multi-stage Compressor

What is a Single-stage Compressor?

A single-stage compressor is one where the compression will take place in a single stage. This means it will take the media, compress it, and throw it out. A compressor does this with the help of a piston inside. The piston moves forward and reverses continuously. When the piston goes down, it takes the incoming media from a large volume area. When the piston goes up, it pushes that media to a lower volume area.

Due to this, the pressure of the media increases and it rapidly comes out. The piston moves up and down through a rotating crankshaft. The crankshaft will be at the bottom position, the piston above it, and the media above it. When the crankshaft rotates for a pulse, it will push the piston up and as the crankshaft stops rotating, it will come down to its original position and move back the piston down again.

This cycle repeats itself as long as the compressor is powered on. The piston speed also determines the speed at which the media will be drawn out. This has a direct impact on the media pressure.

What is a Multi-stage Compressor?

As the name suggests, this compressor will have multiple stages for compression. The most used one is a two-stage compressor. In this, the first-stage piston will compress the media. Then, instead of passing it to the outlet, it will be passed to a second-stage piston.

That stage will be of smaller size, but of higher speed. So, this will compress the media again and the final outlet will be a very highly pressurized media. It is to be noted that the volume decreases as the stage increases. Otherwise, the compression will not work at all.

Difference between Single-stage and Multi-stage Compressor

The main difference is that a single stage will have a single piston and cylinder, but the multistage will have multiple pistons and cylinders.
Single-stage compressors are used in smaller applications, and multistage is used in bigger, more critical applications.
Single-stage is obviously cheaper than multistage compressors due to the technology used in it.
The multistage compressor provides a higher efficiency and output, which makes it suitable for applications where very high pressure is required. It will be best to use it instead of using multiple single-stage compressors.
The temperature efficiency of a multistage compressor is higher than a single-stage compressor. This means that a single-stage compressor can get damaged first after prolonged use due to overheating.
The starting torque of a single stage is higher than a multistage compressor. Even, the torque graph of multistage is more stable than a single stage one.
Leakage chances and chances of failure is higher in single stage one. This is because multistage allows installation of sensing instruments at every stage, as compared to a single one where sensing elements are usually not feasible to install.