Key components of a process compressor and their functions

There are several different types of process compressors, but they all serve the same general purpose: compressing gases or vapors for further use. Each part of a process compressor plays a unique role. Below, we break down the key components to help you better understand these essential machines.

Process compressor parts

Compressor casing

Think of this as the house for your process compressor, forming a protective barrier between the internal workings and the outside world. Robust enough to cope with internal loads, the outer periphery of the casing is unlikely to be under full pressure (although in some compressors it does act as pressure containment).

Rotor assembly

n centrifugal compressors, the rotor assembly includes the shaft and impellers. In screw compressors, you’ll find screws. In both cases, rotational energy is used to increase the gas pressure. Find out more about how different process compressors work here.

Impellors or other compression elements

• Centrifugal compressors often have multiple stages of impellors to boost gas velocity.
• Screw compressors use helical, screw-shaped rotors to compress gas by reducing its volume.
• Reciprocating compressors rely on pistons to compress the gas.

Diffusers

In continuous-flow compressors such as centrifugal or axial types, diffusers convert kinetic energy into pressure energy. Using Bernoulli’s principle, a diffuser slows down the velocity of the gas, which increases its pressure. Diffusers are often gradually widening channels which cause the velocity of the gas to decrease and thus the pressure increases.

Volutes

Volutes are stable, pressurized process compressor parts that act as collection chambers that guide the compressed gas to the next stage.

Bearings

Bearings aren’t directly involved in compression but are critical for stability and support. Depending on the compressor type, they:

• Minimize friction between moving parts
• Maintain shaft alignment
• Absorb shock and transfer vibrations/loads to the casing

Seals

Seals prevent pressurized gas from leaking into the atmosphere or into other machine sections. Reliable sealing is essential for safe and efficient operation.

Intercoolers/aftercoolers

Compressing gas generates heat. Cooling is important to:

• Maintain efficient compression (hotter gas is less dense, requiring more energy and money to compress)
• Protect equipment from heat damage

Intercoolers are placed between compression stages, while aftercoolers are after the final stage, cooling gas before it’s delivered to its process/stored.

Suction and discharge nozzles

These nozzles control how gas enters and exits the compressor. They are often fitted with flow-controlling elements to regulate performance.

Lube oil and seal support

Bearings and seals require lubrication and cooling to operate reliably. Compressors typically feature oil reservoirs, pumps, and filtration systems as part of their support infrastructure.

Controls and supporting instruments

Process compressors are equipped with monitoring systems for pressure, temperature, flow, and vibration. This data allows operators to maintain efficiency and prevent issues.

For example, if vibration levels rise while flow decreases and temperatures spike, it could indicate fouling and should be investigated immediately.

Get in touch

We hope this guide gave you a clear introduction to the essential parts of a process compressor.

At Rochem, we specialize in equipment and chemicals for process compressor cleaning. If you manage an axial or centrifugal process compressor, our industry-leading products can help you restore efficiency and extend equipment life. For questions or product information, contact our knowledgeable team today.