What Is a Compressed Air Booster? A Technical Guide for UK Industry

Most factories and industrial facilities rely on compressed air systems to deliver a steady supply of air pressure, typically in the range of 7 to 13 bar. This level is sufficient for many everyday applications like pneumatic tools and general automation. However, some operations are far more demanding and require higher air pressure levels to maintain efficiency. In these cases, a standard air compressor often falls short.

In this article, we discuss what a compressed air booster is, how it works, and why a booster is important for your pressure-specific efficiency and reliability.

What is a Compressed Air Booster?

A compressed air booster, often referred to as a pressure amplifier or booster pump, as the name suggests, is a machine that further amplifies the pressure of already compressed air. It’s important to note that a booster is not a complete air compressor on its own. It is always used downstream of an upstream primary compressor, with the two of them forming a two-stage air compressor system.

The only difference between a booster and a regular air compressor is the inlet source.

With the primary compressor handling the high-volume work, the booster manages the specialised high-pressure tasks. By splitting the workload, each machine can operate in its most efficient range.

A compressed air booster increases pressure from existing plant air without running the whole system at high pressure.

Technical Specifications & Details

Understanding the capabilities of these machines is vital for selecting the right air booster. While specifications vary by manufacturer, industry-leading models like the Atlas Copco booster range generally offer:

• Pressure Range: Standard industrial boosters typically elevate pressure to 20–40 bar (e.g., for PET blowing). Specialised high-pressure compressed air units, such as the Atlas Copco LB or D-Booster series, can reach up to 300+ bar.
• Flow Rates: From small units delivering 0.5 m³/min to large-scale process boosters handling over 100 m³/min.
• Media Types: While most handle standard plant air, many are designed as air and gas boosters, capable of compressing nitrogen for laser cutting or inerting processes.

Reasons Your System Might Need a Booster

Adding a booster to your existing air compressor system can have surprisingly significant operational and financial benefits.

• Impressive Energy Savings: Generating high pressure air is an energy-intensive process. For every 1 bar increase in pressure, energy consumption rises by approximately 7%. Using a pressure booster creates a “dual-pressure” network, allowing the main system to run at a lower, more efficient base pressure, drastically reducing overall energy consumption.

• Cost-Effective Upgrades: If an existing process needs to be upgraded to a higher pressure, it can be more effective to add an air compressor booster rather than replacing the entire system or purchasing a standalone high-pressure compressor, which could be underutilised for extended periods.
• Improved Operational Flexibility: Air booster systems can deliver compressed air at various pressure levels to different systems. For instance, the same main air compressor could service a 40-bar moulding machine as well as your 7-bar pneumatic tools.
• Extended System Lifespan: By allowing the main air compressor to operate at a lower discharge pressure, a compressor and booster system can reduce the mechanical stress on its critical internal parts. This can lead to reduced maintenance costs and a longer service life for your air compressor.

How Compressed Air Boosters Work

Users often ask about the air booster pump working principle. A booster works on the principle of Boyle’s Law. This law states that reducing the volume of a given mass of gas will cause an increase in pressure. Most compressor boosters use reciprocating piston technology with an inlet, a compression chamber, and a discharge.

1. Inlet: Already pre-compressed air from the main system is piped into the booster which fills a cylinder.
2. Compression: The piston is driven into the cylinder by a drive mechanism reducing the air or gas volume and increasing the pressure.
3. Discharge: The outlet valve opens, and the piston forces the now pressurised air into the discharge line.
   

Key operational features include:

• Drive Mechanism: Boosters can be purchased as electric motor-driven units or as pneumatic air-driven boosters, which use incoming air to provide power. These units require no electricity to operate and are ideal for hazardous environments.
  
• Multi-Stage Compression: To efficiently generate very high pressures, the compression process is frequently broken into stages. Air is compressed to an intermediate pressure, then cooled, and finally passed to a second, smaller cylinder to achieve the final high pressure.
• Intercooling: Cooling the air between stages is critical as compressing air makes it hotter. Hot air is less dense and takes more energy to compress. Intercoolers lower the temperature of the air, making it denser, and the second compression stage more efficient. The lower air temperature also reduces thermal stress on components, increasing their reliability. This increase in efficiency means lower energy use and a safeguard for your capital investment.
  

Types of Compressed Air Boosters

The right compressed air booster to select will depend on the pressure, flow and purity of air requirements of your application.

• Piston vs. Screw: Reciprocating piston boosters are by far the most common type and provide rugged construction and extremely high pressures. Rotary screw boosters (like the Atlas Copco ZD series) are a newer design that are used in medium-pressure applications. Choose the right screw compressor booster if you require quieter operation and a smoother, pulsation-free flow.
  
• Oil-Lubricated vs. Oil-Free: Oil-free boosters are used in processes where air purity is critical, and no trace of oil can be permitted to contaminate the compressed air. This is particularly important for use in food and beverage, pharmaceutical, and electronics manufacturing. Oil-free units can be designed to provide air that is certified to ISO 8573-1 Class 0, the highest air purity rating.
  
• Single-Acting vs. Double-Acting: Single-acting piston units only compress air on one stroke of the piston, resulting in a pulsed flow whereas Double-acting boosters compress air on both the forward and return stroke of the piston, providing a smoother, more continuous output. Double-acting piston units are typically used for applications that need maximum immunity to pressure drop or pulsation.

Key Applications in UK Industries

Compressed air boosters are vital in many areas of industry in Scotland and the rest of the UK.

• Food & Beverage: Blow moulding of PET bottles requires a clean, oil-free air supply at around 40 bar. The Atlas Copco D-Booster is a market favourite here for its Class 0 certification.
  
• Manufacturing: Where high-pressure air is a cheap alternative to assist gas to blow the molten metal clear in laser cutting, instead of costly bottled nitrogen. Typical pressures are 20-35 bar.
  
• Automotive & Aerospace: Pressure and leak testing of components at 50-300 bar or more to check their integrity.
• General Engineering: To uprate the force of existing pneumatic cylinders and clamps, where a full conversion to hydraulic is not justified.
• Pharmaceutical & Food Packaging: Boosters are also used to increase the pressure of on-site generated nitrogen for inerting, flushing, or modified atmosphere packaging, helping reduce reliance on bottled gas. Using nitrogen and air boosters eliminates the logistics of swapping high-pressure cylinders.
  

Selection and System Integration

Correctly sizing and installing a booster is critical for performance. The process requires expert analysis of your discharge pressure, flow rate, inlet pressure, air quality needs, and duty cycle.

A professional system design and installation is vital. Key considerations include:

• Pipework: Pipework should be specified to handle the maximum discharge pressure; in many applications, this means heavy-duty pipework such as stainless steel. Routing of pipework should make use of large radius elbows where possible to minimise pressure drop.
• Ancillaries: The system will also need to have suitable pre-filters to protect the booster, as well as aftercoolers and a high-pressure receiver tank to dampen pressure peaks and bleed moisture.
• Safety: Vibration mounts should be used. Installation should follow the guidance of best practice from professional bodies such as the British Compressed Air Society (BCAS).

Common Challenges & Solutions

Even with the best equipment, issues can arise if the system is not managed correctly. Here are common problems with booster installations:

• Pressure Drop: Often caused by undersized piping or clogged filters. Ensure your pipework is rated for the flow and pressure.
• Overheating: High-pressure compression generates intense heat. Ensure adequate ventilation or consider water-cooled units like the Atlas Copco DX/DN series for heavy-duty cycles.
• Oil Contamination: If using oil-lubricated boosters, carryover can affect product quality. Use downstream filtration or switch to oil-free technology for sensitive applications.

Maintenance for Longevity

A regular preventative maintenance programme is key to safeguarding your investment and ensuring dependability. Many modern booster systems (such as those using the Elektronikon® Touch Controller) are equipped with smart controllers that monitor pressure readings, service intervals, and predictive maintenance notifications to reduce unscheduled downtime. Although newer units come equipped with advanced control systems that offer service alerts, a consistent schedule of inspections is recommended.

Daily checks should include draining condensate and visually inspecting for compressed air leak issues. Maintenance tasks include changing the lubricant, oil filter, and air filter elements annually, or per the manufacturer’s schedule. Oil-free models, particularly those used in ISO Class 0 applications, often require more frequent diaphragm or seal replacements due to the absence of lubrication, which is something that must be built into your servicing schedule.

UK Compliance: The PSSR 2000 Mandate

Any company that owns a pressure system has a legal obligation under the Pressure Systems Safety Regulations (PSSR) 2000 to ensure that personnel and plant are protected against accidents that can arise from the release of stored energy (pressurised fluids). This is certainly the case for all high pressure air booster installations.

The majority of industrial booster installations will also legally require a Written Scheme of Examination (WSE) to be prepared by a “Competent Person” before the system is put into use. A WSE sets out the extent and frequency of inspection of safety-critical items such as receiver tanks, safety valves etc. Design Air (Scotland) Ltd can advise at the planning stage through to inspection, and will act as your Competent Person to ensure complete compliance.

The Right Solution for Your High-Pressure Needs

A compressed air booster can be a valuable tool in the arsenal of any business that has the need for compressed air at higher pressures. A booster offers the possibility of lower energy costs, more flexibility, and better reliability of the system as a whole, but this is only if it is specified, installed, and maintained properly.

Are you looking for a way to increase the pressure of your compressed air for PET moulding, laser cutting, or leak testing? Design Air (Scotland) Ltd are here to help you with bespoke advice for your site, accurate sizing, and complete service for the installation of your booster.