This image was created with artificial intelligence – marked under Art. 50 of the AI Act, Regulation (EU) 2024/1689. It is a placeholder until the company's photos arrive.Selecting seals for pneumatic systems
Flat gaskets made of rubber in NBR, EPDM, FKM & silicone. Find out all about applications, selection criteria and custom-made parts.
The selection of the right seal in pneumatic systems directly influences the function, service life and efficiency of the entire system. In practice, it repeatedly becomes apparent that failures, leaks or unnecessary wear are often attributable to unsuitable seals. This rarely involves gross misjudgements, but rather details such as material behaviour, friction or the actual operating conditions in the system.
Pneumatic systems operate under dynamic conditions: fast movements, changing pressures and often dry compressed air place high demands on all components. The seal plays a central role here, as it both ensures function and significantly influences the efficiency of the system.
Anyone who selects seals in a targeted manner and assesses the operating conditions cleanly reduces maintenance costs, increases process reliability and sustainably avoids unplanned downtime.
Requirements in pneumatic systems
Pneumatic systems operate with compressed air, often dry or lightly oiled, at changing pressures and high cycle rates. This gives rise to specific requirements for seals that differ significantly from other applications. The focus is on low friction, high wear resistance and stable recovery properties, so that the seal reliably seals even during fast movements. At the same time, the material must be resistant to compressed air and possible oil content and withstand temperature fluctuations.
Compared with hydraulic systems, lower pressures are the main consideration, but significantly higher movement cycles act on the seal. This combination of dynamics and continuous load makes selection particularly demanding.
Overview of seal types
Depending on the application, different seal types are used, each designed for specific types of movement and requirements.
O-rings
O-rings are regarded as a simple and cost-effective solution for many applications. They are used both in static and in simpler dynamic areas and are frequently found in valves, fittings and standardised components. Their strength lies in straightforward handling and broad availability.
Piston seals
Piston seals are used primarily in pneumatic cylinders, where they separate pressure chambers. They are designed for linear movements and must exhibit both a high sealing effect and good wear resistance, as they are permanently in motion.
Rod seals
Rod seals seal the piston rod to the outside and thus prevent compressed air from escaping. At the same time, they protect the system against the ingress of dirt and foreign matter that could impair function.
Wiper seals
Wiper seals perform a protective function by removing contaminants from the piston rod before they enter the system. They are generally used in combination with rod seals and significantly increase the service life of the entire unit.
Materials and their properties
The choice of material decisively determines the performance of the seal.
| Material | Properties | Area of application | Temperature range |
|---|---|---|---|
| NBR | flexible, good abrasion resistance | standard pneumatics | approx. -30 °C to +100 °C |
| FKM | high temperature resistance | demanding environments | approx. -20 °C to +200 °C |
| PU | very wear-resistant | dynamic applications | approx. -30 °C to +80 °C |
| PTFE | extremely low friction | high-performance applications | approx. -200 °C to +260 °C |
The choice depends heavily on temperature, cycle rate and mechanical load.
How to select the right seal
- Movement present: static or dynamic
- Cycle rate: low or high-frequency
- Temperature range: constant or fluctuating
- Compressed air: dry or oiled
- Environment: clean or exposed to dust and moisture
Decision logic from practice
| Situation | Recommendation |
|---|---|
| High cycle rate, dynamic movement | PU seal |
| Very low friction required | PTFE seal |
| Standard application, moderate load | NBR O-ring |
| High temperatures | FKM seal |
| Dry compressed air | PU or PTFE |
Selection criteria in detail
- Pressure and load: Even at moderate pressures, high cycle rates generate considerable loads that the seal must absorb permanently.
- Speed and cycle rate: High movement frequencies require materials with low friction and high abrasion resistance.
- Temperature: Temperature fluctuations influence elasticity and sealing effect and must be taken into account when selecting the material.
- Lubrication: Dry compressed air places higher demands on the seal than oiled systems.
- Environmental influences: Dust, moisture or chemical influences have a direct effect on the service life of the seal.
Typical mistakes in selection
- wrong material for the temperature range
- unsuitable seal for dynamic load
- failure to take the cycle rate into account
- combination of incompatible materials
- insufficient protection against contamination
Typical consequences in practice:
- leaks after just a few operating hours
- increased compressed air consumption
- erratic or jerky movements
- premature complete failure of the component
In practice, these mistakes frequently lead to premature wear or complete failures.
Service life and maintenance
The service life of seals depends heavily on the operating conditions. In standard applications, seals frequently achieve several million cycles, while at high cycle rates or with dry compressed air, significantly shorter service lives can occur.
Typical influencing factors:
- high cycle rate significantly reduces service life
- lack of lubrication increases friction and wear
- contamination leads to mechanical damage
Regular visual inspections and planned replacement significantly reduce unplanned failures.
Typical areas of application
Pneumatic seals are used in many industrial areas. In mechanical engineering, applications with high cycle rates and repetitive movements dominate. In automation, the focus is on speed and wear resistance. In food technology, hygiene requirements and material compatibility also play a role.
Practical examples
In industrial practice, it becomes clear just how much the requirements vary depending on the application. In automated systems with high cycle rates, wear-resistant PU seals are frequently used, as they can reliably absorb continuous movement. In classic compressed air systems with moderate load, by contrast, O-rings made of NBR are often sufficient, provided temperature and ambient conditions are within the standard range.
In precision applications where exact movements are required, PTFE seals are frequently used, as their very low friction enables particularly uniform sequences. Selection is therefore always oriented directly to the specific application and the real loads in the system.
Recommended action
The selection of a seal should be consistently based on the actual operating conditions. Standard solutions offer quick availability, but quickly reach their limits in dynamic or demanding applications. What is decisive is the combination of a suitable material, a suitable design and a realistic assessment of cycle rate, temperature and load.
In practice, it becomes apparent that clean selection in advance already determines the economic efficiency of the entire system. Anyone who selects in a targeted manner here reduces failures, saves maintenance costs and sustainably increases operational reliability.
Are you unsure about selecting the right seal for your application? Targeted matching to your operating conditions prevents misjudgements and significantly increases the service life of your components.
Limits of standard solutions
Standard seals are suitable for simple applications with stable framework conditions. At high cycle rates, extreme temperatures or special requirements for friction and precision, they quickly reach their limits. In such cases, specialised materials and adapted seal geometries are required.
Frequently asked questions
Which seal is suitable for dry compressed air?
For dry compressed air, wear-resistant and low-friction materials such as PU or PTFE are particularly suitable.
What is the difference between pneumatic and hydraulic seals?
Pneumatic seals are designed for high cycle rates and low friction, while hydraulic seals must absorb higher pressures.
Which seal at high speed?
At high speeds, materials with low friction such as PTFE or optimised PU seals are advisable.
How long do pneumatic seals last?
Depending on the application, several million cycles. High cycle rates and dry air significantly reduce service life.
How do I recognise a worn seal?
Typical signs are pressure loss, leaks, erratic movements or noises during operation.
Which seal for pneumatic cylinders?
Piston and rod seals are used for cylinders. In dynamic applications, PU seals are particularly widespread.
Which seal at high temperatures?
FKM seals are suitable for high temperatures, as they remain thermally stable.
Our rubber sheets
For industry and trade, we offer a wide variety of rubber sheets.
SBR rubber sheet
Our high-quality SBR rubber sheet (styrene-butadiene rubber) is the solution for numerous industrial and commercial applications. This rubber sheet is manufactured from first-class styrene-butadiene rubber and stands out through its outstanding physical properties.
EPDM rubber sheet
Discover the versatility and reliability of our EPDM rubber sheet, which is manufactured from ethylene propylene diene monomer (EPDM). This high-quality elastomer solution has been specially developed to meet the most demanding industrial and commercial applications.
NBR rubber sheet
The NBR rubber sheet is a high-quality industrial product that has been specially developed for applications requiring excellent resistance to oils, greases and various chemicals.
Viton rubber sheet
The Viton rubber sheet is a high-quality technical product that is used for a wide range of industrial applications. Manufactured from fluoro rubber (FKM), it offers outstanding properties that make it the ideal choice for extreme conditions.
FKM rubber sheet
The FKM rubber sheet is a high-quality technical product that is ideal for use in demanding industrial applications. Manufactured from fluoro rubber (FKM), it stands out through a wide range of outstanding properties that make it the optimum choice for extreme operating conditions.
Silicone rubber sheet
The silicone rubber sheet is a first-class technical product that has been specially developed for applications placing high demands on temperature resistance and flexibility.
PUR rubber sheet
The PUR rubber sheet, manufactured from high-quality polyurethane, is a technically advanced product that has been developed for applications placing the highest demands on abrasion resistance and mechanical load capacity.
Neoprene rubber sheet
The neoprene rubber sheet, manufactured from high-quality chloroprene rubber (CR), is a versatile technical product that is ideal for a wide range of industrial and commercial applications.
