This Resource Centre provides general guidance only. Always follow the equipment manufacturer’s instructions, the product technical data sheet and your site’s safe system of work. Isolate stored energy before maintenance. For safety-critical, regulated or uncertain applications, ask a competent engineer or the product manufacturer to confirm the specification.
Start with the job the cylinder must perform.
Force
Theoretical force is based on effective piston area and pressure, but real output is lower because of friction and pressure losses. On the return stroke of a double-acting cylinder, the piston rod reduces the effective area. Apply an appropriate design margin and consider the load throughout the complete movement.
Stroke and installation
Choose the required working stroke without using the cylinder as a mechanical stop unless it is designed for that duty. Check mounting style, alignment, rod loading and space for fittings and sensors. Side load and misalignment can cause rapid seal and bearing wear.
Speed
Speed depends on available flow, valve and pipe size, load and cushioning. Use flow controls in the arrangement recommended by the manufacturer. Very high speed or heavy load may require external stops or shock absorbers.
Single- or double-acting
A single-acting cylinder uses air in one direction and a spring or external force for return. A double-acting cylinder uses air for both directions and offers better control of the complete cycle.
Environment
Confirm temperature, corrosion, washdown, dust, cleanroom or food-environment requirements. Select suitable rod material, seals, scrapers and lubrication.
Safety
Loss of compressed air can allow a load to move. If unintended motion could injure someone, the circuit needs a risk-assessed safety solution rather than reliance on the directional valve alone.
Need help sourcing the item?
Send the manufacturer, reference, photographs and operating details.