Piston Compressor for Dive Fills, Quiet Workshops or No Mains?

You need air beyond the usual garage compressor: filling dive cylinders, running quietly beside a bench, or working with no mains supply.

Match pressure, noise and power to the job. PartsForMachines lists 48 compressors in its Piston Compressor range, from 13A breathing-air units to silenced cabinets and petrol or diesel models.

Which Compressor Can Fill a Dive or BA Cylinder, and How Fast?

A high-pressure breathing-air compressor. Other piston compressors in our range are typically rated at 7 to 11 bar, while breathing-air units pump to 232 or 300 bar. A 232-bar unit cannot fill a 300-bar cylinder to full, and no cylinder should be filled above the working pressure marked on it.

Fill time follows the charging rate. The Coltri ICON LSE 100 EM 232-bar compressor delivers 100 L/min on a 13A supply. It takes about 20 minutes to fill a 10-litre cylinder from empty to 200 bar. A three-phase 315 L/min unit needs about 6.2 minutes.

How Do I Keep the Air From a Breathing-Air Compressor Safe?

Keep the intake clean, the filters fresh and the moisture out, then have the air tested. Engine exhaust carries carbon monoxide, so site the intake in clean, open air, well away from any exhaust, including the compressor's own on petrol and diesel models.

Change filter cartridges as the maker's manual directs, using the hour counter where fitted. Cartridge life also depends on air temperature, so check the maker's correction for hot conditions. Check, too, whether the filter includes a catalyst, which converts carbon monoxide. Drain condensate as the manual says, or let the machine do it: the ERGO 315 ET 300-bar compressor has an automatic condensate drain and a Maxifilter system.

Can I Box In a Noisy Compressor Without It Overheating?

Only if cool air can get in and hot air can get out. Poor ventilation, or hot air drawn back into the intake, can make a compressor overheat, so a home-made box needs proper vents or ducting to carry the heat away.

A factory cabinet is the simpler route. The SIP NB5.5/270 silenced compressor pairs a soundproof cabinet and intake silencer with a low-noise belt drive. It is rated at 64 dB(A), against 78 dB(A) for a 24-litre oil-less site compressor. Every 10 dB(A) less sounds roughly half as loud.

No Mains on Site: Petrol or Diesel Compressor, or a Generator?

Often an engine-driven compressor, which needs neither mains nor a generator. An electric motor can draw several times its running current as it starts, so a generator must be sized for that start-up surge, not just the running load.

To move round a site, the Clarke XPP15/50 portable petrol compressor is wheel-mounted and gives 15cfm displacement at up to 7 bar. For a fixed off-grid workshop, the SD26KE150 diesel gives 25cfm displacement with electric start. Never run a petrol machine indoors or in an enclosed space unless the ventilation has been properly assessed. A fixed diesel also needs good ventilation, with its exhaust taken to open air.

What Should I Check Before I Buy?

• Maximum pressure: 7 to 11 bar for tools and site work, or 232 or 300 bar to suit your breathing-air cylinders.
• Output: free air delivery (or displacement) for air tools, or the charging rate in L/min for cylinder fills.
• Power: 110V, 13A, a higher-rated single-phase circuit, three phase, or a petrol or diesel engine.
• Noise rating in dB(A), and room for cooling air if it will sit in a cupboard or corner.
• Duty and air quality: cooling breaks or 100% duty, and oil-free air with a dryer for sensitive work.

Not sure which suits your job? Contact the PartsForMachines team by WhatsApp, telephone or email with your cylinders, tools or power supply, or browse the Piston Compressor range.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Will a breathing-air compressor run on a 13A socket?

Some will. The ICON LSE 100 EM models are built for 13A single phase, but the Mini Silent 100 EM needs 16.5A, the SMART 125 EM 18A and the ET models three phase. Above 13A, ask an electrician whether your circuit can take it.

Can a small breathing-air compressor fill cylinders back to back?

Only for a few fills. Small units such as the ICON LSE 100 ET should run for 100 minutes at most, then cool down: at least 30 minutes on the Mini Silent 100 EM. The ERGO 315 ET is built for continuous charging.

Are auto stop and auto drain worth having?

Yes, if you fill often. Auto stop shuts the compressor down at the set pressure, protecting the cylinder, and auto drain purges moisture for better air quality. Both are options on the ICON LSE 100 EM and standard on the ERGO FA models.

Does the air from a breathing-air compressor need testing?

Yes. Compressed breathing air is judged against the European standard EN 12021. Have samples analysed by a laboratory at regular intervals, commonly every three months, and follow any stricter local rules.

Is there a portable breathing-air compressor for boats or remote sites?

Yes. The petrol ICON 100 SH weighs 37kg, is easy to carry in a vehicle or boat, and fills a 10-litre cylinder to 200 bar in about 20 minutes. The ERGO diesel has electric start. Keep the intake well away from the exhaust.

Are oil-free compressors always noisy?

Not always, as ratings vary widely between oil-free models. The Genesi S 24/10 is rated at about 65 dB(A), or about 50 dB(A) in its optional MINI BOX enclosure, while the NuAir OM197 site compressor, also oil-free, is rated at 78 dB(A).

What supply does a silenced workshop compressor need?

Check before you order. The 100- and 200-litre silenced cabinets run on 230V at 16A, while the 270-litre cabinets need a 400V supply at 20A. Without 400V, choose a smaller cabinet and check your circuit can supply 16A.

What is an oil-free compressor with a dryer for?

Work where oil or moisture would spoil the result, such as dental, food and laboratory work. The MGF CS50/25 oil-free cabinet compressor pairs a membrane dryer (-20°C dew point) with a 100% duty rating, runs at 58 dB(A) and is rated zero oil trace.

Is it worth buying my own dive fill compressor?

That depends on how often you fill. Budget for running costs as well as the machine: filter cartridges, oil and regular air tests. Then size it to your use, since a 100 L/min unit is meant for one cylinder at a time.