Industrial compressors have been around for over a century and continue to be a vital component in busy commercial, industrial, and residential environments.
Piston air compressors are best suited to small, compressed air requirements. These compressors support higher pressure levels using a reciprocating air methodology. They can meet industrial air needs within a limited installation footprint.
This blog post considers the work principles behind different types of piston compressors, their pros and cons, and other useful information.
1. What is a Piston Compressor?
A piston compressor uses a crankshaft to move a piston inside a cylinder. The piston draws in air as it moves downward and compresses it during the upward stroke, sending it to a tank or directly to the supply system.
You can find these machines in single-stage and two-stage designs. Single-stage models compress air once, while two-stage versions compress it twice for higher pressure. At Wilson’s Workshop in Manchester, the two-stage units are preferred for their 10-bar output capacity when running pneumatic riveters.
Both oil-lubricated and oil-free piston compressors exist. Oil-lubricated models suit general workshop use, while oil-free versions are necessary in medical centres and food production facilities.
Piston compressors offer good value and take up minimal space in tight workshops. They work well for intermittent use but are not ideal for constant operation. Stanley’s Garage in Leeds runs its 3 HP model for 15-minute bursts followed by cooling periods.
These machines tend to make more noise than other compressor types. They also need regular maintenance – belt checks, bearing lubrication, and valve cleaning every 250 hours. The gasket on the cylinder head typically needs replacement after about 2,000 hours of use.
For many small businesses, a piston compressor provides sufficient performance and pressure at a reasonable cost. Most models sold in the UK operate on standard 240 V power, though larger units may require a three-phase supply.
2. How does a Piston Compressor Work?
A piston compressor first lets air through the intake valve to the internal cylinders.
The piston’s downward stroke creates a vacuum that the air fills. Later, the piston’s upward stroke compresses the air. The air is released via the exhaust valve once the necessary air pressure level is reached.
The operational process is as follows:
Intake Phase: air is received through the intake valve. It is filtered to avoid internal contamination and potential oxidation or part damage.
Compression Phase: the piston reduces the internal space occupied by the filtered air. This begins compressing the air until it reaches the optimal pressure level to support operations.
Discharge Phase: the compressed air is released through an exhaust valve to the air piping system or into a storage tank.
Talk with our compressor experts at J Ll Leach to discuss your requirements.
3. Types of Piston Compressors
Single-Stage vs Multi-Stage Compressors
Piston compressor machines are either single-stage compressors or multi-stage compressors. Each has its use.
Single-stage compressors – These compressors use a single-stroke motion to compress air, generating only moderate pressure. Small workshops or other small environments often find these sufficient to power air tools or meet existing compressed air demand.
Multi-stage compressors – Using multiple cylinders allows increasingly higher air compression as air flows through each stage. It also permits some air cooling, which reduces the requirement for an aftercooler or air dryer system. Multi-stage piston compressors support heavy-demand scenarios.
Oil-Lubricated vs Oil-Free Compressors
Oil-injected and oil-free piston compressors deliver credible performance. However, they are built to support different objectives.
Oil-lubricated compressors: internal parts are lubricated using standard or synthetic oil. Either pressure lubrication or splash lubrication methods are adopted. This reduces internal friction, improves performance, and extends equipment lifespan. However, the maintenance requirement is increased.
Oil-free compressors: some industries, like healthcare and food manufacturing, require zero oil in compressed air to prevent product contamination. Oil-free piston compressors use lubricated bearings and grease-free systems to support this requirement and meet the ISO 8573-1 Class 0 standard. Original designs with fewer moving parts reduce unwanted friction, and internal fans prevent overheating.
4. Applications of Piston Compressors
Piston compressors are commonly used in industries where compressed air is not needed continuously. They are compact and provide good value for intermittent use in various settings.
Common applications include:
- Workshops and Manufacturing: found in small to medium workshops running pneumatic tools. The Davies Metalworks in Sheffield runs three 5HP units to power their grinding and cutting tools during 8-hour shifts.
- Automotive: garages use them for tyre inflation, spray painting and air tools. Morrisons Garage in Bristol has used the same twin-cylinder model for 15 years, servicing it quarterly.
- Construction: their transportability suits on-site work with drills, nail guns, and breakers. Most units weigh 45–80 kg and require two people to move safely.
- Healthcare: oil-free models deliver clean air for dental equipment and laboratory instruments. They typically operate at 50–65 decibels to minimise disruption in treatment rooms.
- Food and Beverage: used in packaging, bottling, and control systems. Barton’s Brewery in York uses piston compressors with food-grade filters that need changing every 200 operating hours.
- Agriculture: farmers employ these for milking systems, crop spraying, and maintenance. Many run on a 240 V supply, though larger dairy operations often install three-phase models.
These compressors perform well for intermittent demands but are not designed for constant use. Most require a 20–30 minute cooling period after an hour of operation. If your business needs air pressure in bursts rather than continuously, piston compressors offer practical performance at a reasonable cost.
5. Advantages of Piston Compressors
There are some advantages to using piston compressors. Here are a few:
Cost-effective – Upfront capital investment is lower than more technologically advanced types, such as screw compressors.
Durability – Uncomplicated, time-tested design provides longevity regardless of the amount of regular use.
Versatility – Compact piston compressors are used in small and large businesses. Oil-free compressor models exist to meet different needs.
High pressure – Do not let their size fool you. This compressor type supports high-pressure air output.
Please get in touch to determine whether piston compressors are the right choice for your business.
6. Disadvantages of Piston Compressors
Every compressor type has some negatives. Here are the disadvantages of piston compressors:
Energy efficiency: they are now more energy efficient than earlier models. However, other compressors consume less energy to produce the same air volume.
Noise output: piston compressors are loud compared to rotary screw compressors. Plan accordingly by using soundproofing or providing ear protection for people nearby.
Maintenance needs: oil-injected machines require more maintenance than oil-free.
7. Maintenance Tips for Piston Compressors
Below are some useful maintenance tips.
Air filters: replace filters on a schedule. This ensures consistent air quality and protects internal components from excess wear.
Visual inspections: look over the equipment to identify early signs of excess wear and tear. This helps catch potential part failures before they cause downtime, protecting operational efficiency.
Lubrication: oil-injected compressors require periodic oil replacement to avoid unintended wear and impaired performance. Synthetic oil requires replacing less frequently than standard oil. Consistent lubrication prevents equipment lifespan degradation.
Overheating: to prevent a compressor from overheating and breaking down, monitor pressure levels and internal temperatures for unexpected variances from the norm.
Servicing: for regular servicing needs, refer to the manufacturer’s guidelines. Servicing delays negatively affect equipment lifespan.
Conclusion
Piston compressors are the most common compressors in business environments. They are suitable for less demanding air requirements, and their classic design, simpler internal mechanisms, and high-pressure capabilities make them adaptable machines.
While not intended for non-stop 24/7 operations, these powerful, low-maintenance compressors are popular. However, is a piston compressor right for your business? Get expert advice from J Ll Leach to make an informed choice.
FAQ
What is the difference between a piston compressor and a rotary screw air compressor?
Piston compressors (reciprocating compressors) use pistons driven by a crankshaft to compress air. Rotary screw models compress air using two interlocking helical screws.
Piston types work well for intermittent use and smaller jobs, while screw compressors handle continuous operation in industrial settings better.
Is an oil-free air compressor better than an oil-lubricated one?
The choice depends on your needs. Oil-free compressors are necessary in food production, pharmaceutical manufacturing, and labs where air purity is important.
They prevent contamination but often need more frequent maintenance. Oil-lubricated models last longer and run more quietly, making them suitable for workshops and factory floors.
What are the typical uses for a piston or reciprocating compressor?
Piston compressors serve many purposes in settings where constant operation is not required. Mechanics use them to power air tools in garages.
Dentists rely on them for a clean air supply. Their practical design allows them to deliver high-pressure air when needed without running continuously. Many small businesses choose them for their reliability and reasonable running costs.
