What is a Piston Compressor?

Piston compressors, also known as reciprocating compressors, have been one of the most popular types of air compressors since the 18th century. While piston compressors still work on the same principle today as they did centuries ago, modern versions are relatively quiet, durable, and versatile compared to their predecessors.

Nevertheless, there are many specific types of piston compressors to choose from, meaning it is essential to understand the ins and outs of each one, so that you can invest wisely in the most suitable equipment for your environment and application.

Here at Anglian Compressors, we have been installing, servicing, and repairing all types of air compressors for businesses in the UK for almost 50 years. Not only are we a premier distributor for the esteemed manufacturer, Atlas Copco, but we are also experts in maximising workplace productivity, which is why we thoroughly inspect your site to recommend the most reliable and energy-efficient solutions available, whether you need air compressors, dryers, gas generators, filters, or a combination of the above.

We explain how piston compressors work, below, before introducing you to the available types. We also discuss the most common applications for reciprocating compressors and their pros and cons to help you purchase the most suitable appliance for your workplace. Do not hesitate to give us a call if you have any questions.

How Piston Compressors Work

Piston air compressors operate using the principle of positive displacement which means that they increase the pressure of the air by reducing its volume. The main components of these air compressors are valves and a piston that moves back and forth inside a cylinder.

Multi-stage compressors use multiple pistons to progressively compress air to higher pressures, incorporating intercoolers between stages to improve efficiency and reduce heat generation​.

You can also buy a reciprocating compressor that uses numerous pistons called multi-stage piston compressors (more on those later).

As the piston moves downwards, it draws air into the cylinder through the inlet valve. When the piston moves back up inside the cylinder, the inlet valve closes, forcing the air inside the cylinder to compress. The compressed air is then pushed through the discharge valve into the storage tank, where it is ready for use. This process is repeated in cycles to ensure you always have a continuous supply of compressed air.

Here is how reciprocating compressors work step by step:

  1. Air enters the cylinder through the inlet valve.
  2. As the piston moves downwards into the cylinder away from the inlet valve, the cylinder fills with air.
  3. The crankshaft powers the piston. As the piston returns to its original position in a stroke of pressure, the air inside the cylinder is compressed through positive displacement (i.e. the air volume is reduced).
  4. Once compressed, the air is sent through the discharge valve to the storage tank where it is ready for use.
  5. The piston compressor repeats the process in cycles to ensure a constant compressed air supply.

Multi-stage compressors operate on the same principle as the single-stage compressors detailed above. The only difference is that multi-stage appliances use numerous pistons and cylinders to create higher pressures.

Types of Piston Compressors

In basic terms, all piston compressors operate on the same principle – the key differences lie in the number of compression stages and whether oil is used.

Single-Stage, Double-Stage, and Multi-Stage Compressors

  • Single-stage compressors complete the compression process in one cycle.
  • Double-stage compressors compress air in two stages for higher pressure output and improved efficiency.
  • Multi-stage compressors reduce operational heat and wear by cooling the air between stages using intercoolers, making them ideal for high-pressure applications​.

Oil-Injected Versus Oil-Free Piston Compressors

  • Oil-injected piston compressors circulate oil to lubricate components like cylinders and pistons. While some residual oil may enter the compressed air, it is usually negligible for non-critical applications.

Oil-free compressors use pre-lubricated bearings and grease-free piston rings to ensure no oil contamination. These are mandatory in industries like food and beverage, pharmaceuticals, and electronics, where even trace oil levels are unacceptable​.

What is a Piston Compressor?
What is a Piston Compressor?

Applications of Piston Compressors

Reciprocating air compressors are used in a wide range of industries, including:

  • Automotive: powering pneumatic tools, spray painting, and tyre inflation.
  • Manufacturing: pneumatic conveying, air-powered tools, and air separation processes.
  • Healthcare: used in medical applications such as dental chairs, ventilators, and laboratory equipment.
  • Commercial and personal settings: utilised in workshops, construction sites, and DIY projects for various air-powered tools and equipment.

Pros and Cons of Piston Compressors

Advantages

  1. Versatility
    • Suitable for light to heavy-duty tasks, making them adaptable across industries.
  2. Durability
    • Robust construction enables them to withstand harsh conditions and high usage.
  3. High-Pressure Capability
    • Piston compressors can achieve high pressures, essential for specialised tasks.
  4. Cost-Effectiveness
    • Lower initial cost compared to other compressor types. Efficient for intermittent air demand.
  5. Ease of Maintenance
    • Simple design allows for straightforward maintenance like oil changes.

Considerations

  • Maintenance: regular lubrication and inspections are required to ensure long-term efficiency.
  • Noise and Vibration: piston compressors can be noisy, often necessitating noise-dampening solutions or isolation mounts.
  • Energy Efficiency: single-stage compressors are less efficient for continuous high-pressure demands than multi-stage compressors.

Discover Our Range of Piston Air Compressors

Are you looking for modern, reliable, and energy-efficient piston compressors? Do you need a professional team of technicians to install your compressor to the highest industry standards? Anglian Compressors have been helping businesses, across a broad range of industries, with all their compressed air needs for over five decades. Whether you are looking for a new solution, servicing, repairs, or just general advice, we are only a phone call away. 

Contact us today to discover our comprehensive range of piston compressors, including energy-efficient models and industry-specific solutions.