The compressive force required for an O-ring to effect a seal is as important as the seal's size, durometer and chemical compatibility. Inadequate squeeze on the cross-section of an O-ring reduces the sealing footprint and can cause failure. The following must be considered for optimum seal integrity:
| • | A squeeze of 20-25% for static and 12-18% for dynamic applications. |
| • | Dimensional tolerances of seals and equipment must be considered to prevent inconsistent compression and possible leakage. |
| • | Balance must be achieved between the physical properties of the seal material (e.g., hardness, tensile strength, modulus) and the compressive force of the application. |
| • | As temperature rises, so does gland fill and subsequent compression due to the thermal expansion of the seal material. Seal and gland designs may have to be adjusted to compensate for this expansion in high-temperature applications (>250°C) |
Average force curves approximate the force necessary to compress standard Chemraz® O-ring cross-sections at three hardness levels - 70, 80 and 90 Shore A, Hardness. The graphs shown on Compressive Force Graphs show the average O-ring compressive force curves for 0.070", 0.103", 0.139", 0.210" and 0.275" cross-sections. Please consult Greene, Tweed Engineering to optimize seal designs while balancing the many trade-offs.
Click here to view Compressive Force Graphs
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