What factors should be considered when designing an O-ring?

What factors should be considered when designing an O-ring?

March 26, 2021

When designing the O-ring, do you know how much the O-ring is used in the programming device? The O-ring squeezes its matching hardware to form an effective seal.

What is O-ring extrusion?

Squeeze is the ratio of the amount of sealing applied from deformation to the percentage of the cross-sectional thickness expressed as a free state. The silica gel sealing ring has an open porous structure and can adsorb many substances. It is a good desiccant, adsorbent and catalyst carrier. The adsorption effect of silica gel is mainly physical adsorption, which can be regenerated and used repeatedly. Add acid to the alkali metal silicate (such as sodium silicate) solution to acidify it, and then add a certain amount of electrolyte to stir to form a silicic acid gel; or add acid or Ammonium salts can also generate silicic acid gels. The "energized" elastomer matrix of the deformed seal cross-section resembles a compression spring; the inherent elasticity of the rubber material makes it push back against the mating component. This contact force block liquid, gas and dry powder, avoiding their flow channel between the rubber seal and the mating hardware.

The greater the squeeze, the greater the force is applied to the hardware and the tighter the seal. When choosing O-rings, try to use O-rings with large cross-sections as much as possible. In the case of the same gap, the volume of O-rings squeezed into the gap should be less than the maximum allowable value of squeezed into the gap. However, this does not necessarily mean that designers should always specify the most crowded. After all, there are many factors to consider, including:

1. Sealed and airtight:

Tighter sealing usually results in higher levels of squeezing. Exceeding a certain level, however, when other factors participate, it may work for an effective sealing, such as stress due to the force of mating hardware.

2. The hardware pressure of mating:

If the squeeze is increased, and its tightening force is too much, it may potentially damage the mating hardware, which depends on the material and hardware design.


3. Use friction and wear:

The presence of higher squeeze also increases the friction of the equipment and the faster wear of the dynamic utilization program. O-ring is a ring-shaped mechanical gasket. It is a ring-shaped elastomer with a circular cross-section. It is generally fixed in a groove and will be compressed by two or more components during assembly. Therefore, Produce a sealed interface. This may be enough to affect the function of the device. For example, in a medical device that involves manual adjustment, an O-ring, which generates excessive friction, may prohibit the physician from properly using the device.

4. Damaged O-ring seal:

With higher squeezing, there is a higher risk, that is, when the clamping device is equipped with an O-ring, it creates a path for fluid or gas flow to wrap around and seal. O-ring pinch breaks the O-ring seal. At the 40% level, pinching is difficult to avoid, while pinching is eliminated at the 25% level.

5. Tightening and eternal deformation:

The squeeze elastic body is applied by the matching hardware, which invents the sealing force, which tends to decay over time. When this force is completely attenuated, the O-ring will retain its shape even if it is no longer squeezed. The contraction change is to measure this decay, expressed as a percentage. When the shrinkage deformation reaches 80%, most O-rings are in danger of losing their sealing ability. It takes a long time for the O-ring to be squeezed at a higher level to reach the level of 80% compression and eternal deformation. Only based on austerity and eternal deformation.