| Operating pressure and motion | Normal and peak pressure, reciprocating speed, stroke length, and duty cycle. | Specify the full operating envelope, including pressure spikes and high-cycle conditions. Confirm that the seal profile and housing are suitable for the application. | Excess pressure, speed, or cycle frequency can increase friction, heat, wear, and the risk of extrusion or leakage. | Application-specific recommendations and test data that state pressure, speed, stroke, temperature, and cycle conditions. |
| Seal material | Air quality, lubricant exposure, temperature, chemical contact, and required flexibility. | NBR is commonly used for general-purpose pneumatic service; polyurethane is often selected for abrasion resistance; FKM may suit higher-temperature or chemical exposure; EPDM is used where its media compatibility is appropriate; PTFE is considered when low friction or broader chemical resistance is needed. Confirm the exact compound and application limits. | Material compatibility helps limit swelling, hardening, cracking, and wear. Material names alone do not define performance; formulation and operating conditions matter. | Compound identification, documented temperature and media limits, and compatibility information for the actual air, lubricant, and cleaning agents. |
| Temperature range | Minimum start-up temperature and maximum seal temperature during continuous and intermittent operation. | Use the seal compound’s documented limits, not a generic material range. Consider heat generated by friction and temperature changes during start-up or cleaning. | Temperatures outside the compound’s suitable range can accelerate aging, reduce elasticity, or change friction and leakage behavior. | Compound-specific temperature data and test conditions, including whether limits apply to continuous or short-term exposure. |
| Air quality and contamination | Moisture, particles, compressor oil, condensate, and the effectiveness of filtration. | Specify the air-treatment conditions and required filtration for the equipment. Keep cylinder surfaces and assembly areas clean during installation. | Particles can score surfaces or damage sealing lips; unsuitable oil or condensate can affect some compounds and increase maintenance frequency. | Guidance on air-quality requirements, compatible lubricants, and seal handling and storage. |
| Seal profile and installation | Rod or piston application, groove dimensions, clearance, surface finish, and assembly method. | Check dimensions and tolerances against the cylinder design. Use the specified installation method and avoid twisting, cutting, or stretching the seal during assembly. | Incorrect groove geometry, surface damage, or installation can cause early leakage even when the material is suitable. | Dimensioned drawings, tolerance information, installation instructions, and inspection records for supplied parts. |
| Service-life planning | Required cycles, acceptable leakage, operating profile, and consequences of downtime. | Set a service-life target in cycles or operating hours and define the conditions used to evaluate it. Compare performance only when test conditions are comparable. | There is no universal service-life figure for a pneumatic seal. Actual life depends on the seal, cylinder, air quality, installation, and duty cycle. | Application-relevant endurance or field data with stated test conditions, failure criteria, and sample size where available. |
| Maintenance and replacement | Access to the cylinder, planned service intervals, spare-part availability, and downtime cost. | Use condition-based inspection where practical; track leakage, sluggish motion, and changes in air consumption. Keep critical replacement seals identified and stored correctly. | Early detection can prevent secondary damage and unplanned downtime. Replacement intervals should be based on operating history rather than a generic schedule. | Recommended inspection guidance, storage-life information, replacement identification, and consistent dimensional specifications. |
| Supplier quality and traceability | Manufacturing controls, batch consistency, dimensional inspection, change management, and technical support. | Evaluate documented quality processes and the supplier’s ability to maintain consistent material and dimensions. A quality-system certificate alone does not establish application performance. | Consistent production and traceability make failures easier to investigate and help reduce variation between replacement parts. | Batch or lot traceability, material documentation, inspection records, nonconformance handling, and notification of material or process changes. |
| Selection note: Confirm all material, temperature, pressure, and life expectations for the specific seal compound and equipment. Published ranges and test results are meaningful only when their conditions match the intended application. |