Library / Engineering / KEVOS® original book
Pneumatics by the Numbers
Sizing, timing, supplying and safely running a small pneumatic system, worked through one carton reject station
Size a pneumatic cylinder, time and cushion its stroke, choose valves and a safe fail state, count air and leak costs, supply clean air and commission and maintain the system.
Start readingAbout this book
Most small factories run on compressed air. Cylinders push, clamp, lift and sort; valves switch them; a compressor in a back room fills a receiver; and a network of pipes and hoses carries the air to every machine. Pneumatics is popular because it is simple, robust and cheap to buy. It is also easy to get roughly right and quietly wrong: cylinders chosen by habit, flow controls set by feel, pressure turned up to cure a problem somewhere else, leaks that hiss for years, and stored energy that surprises the person who disconnects a hose.
This book replaces habit with numbers. It covers pressure and why absolute pressure matters, cylinder force and side load, timing and cushioning a fast stroke, valves and the state a machine should fall into when power or air is lost, air consumption and its cost, supply pressure, air treatment and receivers, isolation and guarding, and commissioning, maintenance and leak hunting. Each chapter works one part of the system through the running case, with calculations checked step by step, and ends with an exercise and its worked answer.
The running case
The book follows a fictional contract packing business of about 30 people, packing rice, flour and dry mixes into cartons on two lines. On line 2, a checkweigher identifies underweight cartons, and the business wants a pneumatic pusher to push each rejected carton sideways off the conveyor into a reject chute. The line runs at 40 cartons a minute. Cartons weigh up to 4 kg. The factory’s air comes from one rotary screw compressor feeding a receiver and a pipe network shared with the other line and the workshop.
All quantities, prices, pressures, timings and results are invented for teaching. This is an illustration. None of it describes a KEVOS® client, supplier or project, and no product or manufacturer is endorsed. Money is in Australian dollars, excluding GST. Electricity is costed at an assumed A$0.30 a kilowatt-hour.
How to use the book
Chapters 1 to 4 design the reject station: the job, the cylinder, the timing and the valves. Chapters 5 and 6 look outward to the air it uses and the system that supplies it. Chapters 7 and 8 cover making it safe and keeping it working. Calculators for several of the steps are in the KEVOS® tools, including pneumatic cylinder force, pneumatic consumption and air leak cost.
Source limits and professional responsibility
No source text was supplied for this book. It applies standard physics, a small number of cited public references and a fictional case. Standards are named by number and scope only, and no values are quoted from them. Manufacturers’ data govern any real component: rated forces, cushioning energies, flow ratings, pressure ratings and response times differ between products. Pneumatic equipment stores energy and moves with force. Machine guarding, isolation and safety functions must be designed and checked by a competent person against the work health and safety law and standards that apply, and nothing here is a substitute for that.
Who this book is for
Maintenance technicians, machine builders, production engineers and owners of small factories who specify, build, modify or look after pneumatic equipment and want to do it with numbers rather than habit.
What you will learn
- Convert between gauge and absolute pressure and size a cylinder from the load, the lowest supply pressure and a sensible load ratio.
- Build a timing budget for a fast stroke, check its kinetic energy and choose flow control and cushioning.
- Choose valves, tubing and a fail state, and calculate air consumption, leak flow and their annual cost.
- Specify supply pressure, air treatment and receiver size, and keep pressure drop small.
- Isolate stored energy, guard pneumatic motion, commission the system and run a leak program that lasts.
Inside this book
Chapters
- 01Understand air, pressure and the jobStart a pneumatic design with the job in numbers, gauge and absolute pressure, free air, compressibility and the cost of compressed air, then decide whether pneumatics suits the task.
- 02Size the cylinder for force and side loadSize a pneumatic cylinder from friction and acceleration loads at the lowest supply pressure, keep a sensible load ratio, check retract force and buckling, and guide side loads.
- 03Set speed, timing and cushioningBuild a timing budget for a fast pneumatic stroke, fire it at the right moment on a moving conveyor, control speed with meter-out flow control and absorb the kinetic energy at the end of travel.
- 04Choose valves, tubing and the fail stateDecide what a pneumatic machine does when power or air is lost, then choose the valve function, flow rating, tubing and exhaust treatment, and draw the circuit so spares match the design.
- 05Count the air and what it costsCalculate a cylinder's free air per cycle and per year, convert it to kilowatt-hours and dollars, and compare it with leaks, open blowing and vacuum ejectors that cost far more.
- 06Supply clean, dry air at the right pressureTrace pressure drop from compressor to machine, fix the restrictions before raising pressure, size a receiver for peak demand, and dry, filter and drain the air so valves and cylinders keep working.
- 07Isolate stored energy and guard the motionManage pneumatic hazards: injurious forces, stored air that moves machines after power is off, guarding, lockable dump valves, verified isolation, hoses, blow guns and noise.
- 08Commission, maintain and hunt leaksCommission a pneumatic station against its brief, record its settings, maintain it on a schedule informed by stroke-time data, and measure, find and fix compressed air leaks so they stay fixed.
Apply This in Practice
Use these KEVOS® tools to try the method from this reading with your own numbers.
Applies this method
Air Receiver Size
Gives the receiver volume needed for a stated shortfall and time.
Applies this method
Compressed Air Leak Cost
Puts a cost on compressed-air leaks, one of the steps in this book.
Applies this method
Compressed Air Pipe Pressure Drop
Works out pressure drop in a compressed-air pipe for a measured flow, as used here to size a larger branch.
Applies this method
Pneumatic Cylinder Air Demand
Works out the air demand of a double-acting pneumatic cylinder, one of the steps in this book.
Applies this method
Pneumatic Cylinder Force and Bore Selection
Works out pneumatic cylinder force, one of the steps in this book.
Applies this method
Vacuum Gripper Sizing (Cups, Diameter, Holding and Evacuation Time)
Sizes vacuum cups for a holding force, the check made on the gripper in this chapter.
Used in Count the air and what it costs
References and source notes
The manuscript and worked examples are original KEVOS® writing. References inform particular concepts; their authors do not endorse this book. Web references were consulted on 26 October 2026.
- U.S. Department of Energy, Advanced Manufacturing Office, with the Compressed Air Challenge. Improving Compressed Air System Performance: A Sourcebook for Industry, third edition (2016). Source for the leak rates of poorly and well maintained systems, the load and unload leak estimate, the pressure-reduction rule of thumb, the guidance that pressure loss should be much less than 10% and the typical overall efficiency of compressed air, used in Chapters 1, 5, 6 and 8. Paraphrased, not quoted.
- Safe Work Australia. Model Code of Practice: Managing the risks of plant in the workplace (current edition). Background for Chapter 7 on managing plant risks, isolation and stored energy. A model code has legal effect only where a state or territory has adopted it; check the version that applies locally.
- ISO. ISO 4414, Pneumatic fluid power: general rules and safety requirements for systems and their components (current edition). Named by number and scope only, in Chapters 4 and 7. No requirements are quoted.
- ISO. ISO 8573-1, Compressed air: contaminants and purity classes (current edition). Named by number and scope only, in Chapter 6, as the way air quality is specified by class. No class limits are quoted.
- ISO. ISO 6358-1 and ISO 1219-1, flow-rate characteristics and graphical symbols for fluid power components (current editions). Named by number and scope only, in Chapter 4, as the bases of valve flow ratings and circuit symbols.
- Standards Australia, Standards New Zealand and ISO. AS/NZS 4024.1 series and ISO 13849-1, safety of machinery and safety-related parts of control systems (current editions). Named by number and scope only, in Chapter 7, as the standards a competent person uses for guarding and safety functions. No requirements are quoted.