The seal used in an application is of immense importance in helping a seal function optimally. When choosing a seal for your application, many factors are considered. Here, we will be discussing the importance of the cross-section of a seal, and how it affects the variance of squeeze.
How Does Variance in Squeeze Affect The Seal Quality?
As the diameter of a part increases, so does the tolerance needed to manufacture the part. Accordingly, as the tolerance increases, so does the variance in the squeeze. Variance is the amount (denoted in percentage) that the seal is not able to provide proper sealing. In order to fabricate a well-functioning product, it is important to reduce this variance. Lesser the variance, greater is the sealing quality. Thus, manufacturers pay a lot of attention to the diameter and tolerance since they directly affect the variance in the squeeze.
For a large gland, a large seal is required. Thus, as the tolerance goes up, so does the cross-section of the seal. The greater the cross section, the better the performance. The variance is also dependent on the raw materials used and the manufacturing techniques. Thus, producing exact replicas of seals is next to impossible.
If we cannot control the consistency of the raw materials and the manufacturing process, we must try to control the cross-section of the seal. Controlling the cross-section will help control the amount of variance of squeeze exhibited by the seal. Thus, we can expect better sealing performance from that particular seal.
If in doubt, refer to The American National Standards Institute (ANSI) for standard tolerances of sealing material. Since the seal plays a vital role in the proper functioning of an application, it is important to choose it correctly.
When fabricating a piece of machinery that needs custom sealing solutions, it is important to involve the engineer designing the seals at the early stages of design, so as to produce an equipment that exhibits perfect sealing and by extension, flawless function.
