Choosing Sealing Elements for Pneumatic Systems
In pneumatic systems, air tightness directly affects production line efficiency. If pneumatic piston seals and pneumatic rod seals are not chosen correctly, the result is pressure loss, low force and high energy consumption.
Different needs in pneumatic applications
Compared with hydraulic systems, the average pressure in pneumatic lines is low, but the duty cycle is much faster. The seal material therefore has to keep its elasticity for a long time.
Selection criteria
- Operating pressure (bar): Do not exceed the maximum pressure given in the product catalogue.
- Cycle rate: Choose low-friction profiles for high-frequency lines.
- Air quality: Filtering and drying extend seal life.
- Breakaway friction: Low breakaway friction is especially important in small cylinders.
Pneumatic piston and rod seals
Piston seals support the build-up of force inside the cylinder, while rod seals prevent air leaks where the rod exits. The two groups should be assessed together.
Industrial applications
Pneumatic sealing plays a critical role in automation lines, packaging machines, food production equipment and press control units. All KASTAŞ product groups are available in the catalogue.
Support from Ada Kauçuk
With your cylinder size, stroke and pressure data, we help you identify the right pneumatic seal code. For technical questions, reach us through our contact channels.
Lubricated or oil-free line?
This is the first question that determines material choice in pneumatic sealing, and it is often skipped.
In lubricated lines a fine oil mist is fed into the air line through a conditioning unit. This film both lowers friction and nourishes the elastomer, and standard NBR profiles last a long time under these conditions. But if a system that has been run lubricated is switched to oil-free, the seals wear rapidly: once the oil film is gone, dry contact begins.
In oil-free (dry) lines there is no such film. In food, pharmaceutical and electronics production clean air is mandatory, so lubrication is not possible. These applications favour self-lubricating PTFE-based profiles and special low-friction compounds.
Cycle count: the real decider in pneumatics
In hydraulics, life is determined by pressure; in pneumatics, by cycle count. A push cylinder on an assembly line may move tens of thousands of times a day. At this scale even a tiny difference in friction per cycle adds up to a large difference in wear.
That is why pneumatic profiles are designed with thin lips and low contact pressure. Fitting a seal made for hydraulics to a pneumatic cylinder — even if the size fits — causes excessive friction, heat and early failure.
The way failure shows itself is different, too. In pneumatics there is usually no sudden breakdown: thrust drops slowly, cycle time lengthens and the compressor starts more often than normal. Monitoring these three values is the most practical way to prevent unplanned stoppages.
Search by size
If you know your cylinder dimensions, list matching products in the size finder and narrow them down to pneumatic profiles with the product group filter.