Pneumatic system for production machines (air supply to cylinders)
Machine pneumatics · Air supply, preparation, valve manifold, tubing and cylinders on a production machine: free-air demand per cycle, supply and return-stroke pressure, ISO 8573-1 air class, receiver size
A machine's pneumatic system turns compressed air into clamping, pressing and transfer motion: air is stored and conditioned, switched by solenoid valves on a manifold, and carried by tubing to cylinders. Three numbers shape its running cost and reliability: how much free air each machine cycle consumes, the pressure it is set to on each stroke, and the cleanliness and dryness of the air reaching the valves.
Complete compressed-air circuits on industrial machines: local receiver, filter, regulator and lubricator units, valve manifolds, tubing and fittings, and the linear cylinders they drive, plus the compressor and dryer package where supplied with the machine. This differs from quarter-turn actuators that open and close process valves: rack-and-pinion and scotch-yoke valve actuators are covered on the Pneumatic actuator page. Cylinders chosen as single components and plant-wide compressor rooms are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 4 sources
Free air per minute from bore, stroke, cycles and pressure
AutomationDirect's worked example takes a 2 in bore, 4 in stroke cylinder making 30 complete cycles a minute at 80 psi. The piston area is 3.14 sq in, one stroke uses 12.56 cu in and a full cycle 25.12 cu in, ignoring the rod. At 30 cycles that is 753.6 cu in, or 0.436 cu ft a minute; multiplied by the 6.44 compression ratio it gives 2.81 cu ft of free air a minute (SCFM, referenced to 70 °F at sea level). [1]
The same page adds that the tubing between valve and cylinder is filled and exhausted on every cycle, and depending on its size and length that consumption can be significant; its tubing calculator assumes equal tube lengths on both ports of a double-acting cylinder and halves the figure for a spring-return cylinder with one supply line. [1]
AutomationDirect also notes that oversizing from a 2 in to a 3 in cylinder more than doubles the air volume, and that correct sizing can cut a cylinder's consumption by at least 15%. [2] Editorial calculation: the bore area ratio is (3 ÷ 2)² = 2.25; and 2.81 SCFM × 28.3 l per cu ft ≈ 80 l of free air a minute for the example cylinder. [1]
List every cylinder on the machine with bore, stroke, rod size, single- or double-acting, cycles per minute and working pressure, plus valve-to-cylinder tube bore and length, so the supplier can total the free-air demand and size the supply.
02
Regulators, short tubing and a lower return-stroke pressure
Seattle City Light advises running compressed air at the lowest possible pressure, stating that every 2 psig reduction saves 1% of energy, and lists long hoses, unnecessary elbows, undersized piping and dirty filters as causes of avoidable pressure drop. [3]
AutomationDirect recommends keeping tubing between control valves and cylinders under 10 ft, because longer runs need more pressure to keep positioning of the load. It reports savings of up to 40% from adding pressure regulators, and gives an example of a pusher cylinder that needs 100 psi on its working stroke but only 10 psi to return, where a spring-return single-acting cylinder removes the return-stroke air altogether. [2]
Editorial calculation: dropping a machine's supply from 90 to 80 psig is five 2-psig steps, about 5% of compressor energy on Seattle City Light's rule of thumb. [3]
03
ISO 8573-1 air classes at the valve manifold
MAC Valves publishes ISO 8573-1:2010 purity classes and recommends class 7:4:3 as the minimum air quality for its valves: particles up to 40 µm (class 7), a pressure dew point of +3 °C or lower (class 4), and total oil of 1 mg/m³ or less (class 3). [4]
Rows are taken from MAC Valves' reproduction of the 2010 table; the standard itself governs. The three digits are read in the order particles, water, oil. [4]
ISO 8573-1 class
Particles 1–5 µm per m³
Pressure dew point
Oil, mg/m³
1
≤ 10
≤ −70 °C
≤ 0.01
2
≤ 100
≤ −40 °C
≤ 0.1
3
≤ 1,000
≤ −20 °C
≤ 1
4
≤ 10,000
≤ +3 °C
≤ 5
State the air class the machine's valves and cylinders need, and whether the machine is supplied with its own filter, dryer or lubricator to reach it.
04
Local receiver, leaks and air to idle machines
For load/unload compressors Seattle City Light gives receiver capacity of at least 3 gallons per cfm, with 5 gallons per cfm recommended, to avoid short cycling. It puts the energy cost of each audible leak at $1,400 a year, says an unloaded compressor still draws 30% of full-load power, and advises shutting off air to equipment that is off line. [3]
Editorial calculation: a 50 cfm compressor would need a receiver of 150 to 250 US gallons, about 570 to 950 l, on that guidance. [3]
05
Send the cylinder list, pressure and air quality together
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Machine: [process; cycles per minute; working hours]
Cylinders: [bore; stroke; rod; single or double acting; quantity]
Pressure: [working stroke; return stroke; supply available]
Valves: [manifold; number of stations; coil voltage; response time]
Tubing: [bore; length valve to cylinder]
Air quality: [ISO 8573-1 class; filter, dryer, lubricator]
Supply: [receiver size; compressor if included]
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
How much air does a pneumatic cylinder use?
In AutomationDirect's example a 2 in bore, 4 in stroke cylinder at 30 cycles a minute and 80 psi uses 2.81 SCFM of free air, before tubing. [1]
Does lowering supply pressure save energy?
Seattle City Light states each 2 psig reduction saves 1% of energy; AutomationDirect reports savings of up to 40% from adding pressure regulators. [3][2]
What air quality do pneumatic valves need?
MAC Valves recommends at least ISO 8573-1 class 7:4:3: particles to 40 µm, dew point +3 °C or lower and oil 1 mg/m³ or less. [4]
Sources and what still needs a direct check
Sources checked 2026-10-12. AutomationDirect sells pneumatic components and publishes the sizing example and efficiency article; Seattle City Light is a municipal electric utility giving compressed-air efficiency tips; MAC Valves is a valve maker stating air quality for its own products.
