What does a negative pressure indicate in terms of a seal's behavior?

A negative pressure indicates that the pressure inside a seal is lower than the pressure outside the seal. This condition often leads to the seal "breathing in," as the external pressure pushes against the seal, drawing air or fluid into it. This behavior is typically observed in systems where maintaining a specific pressure differential is critical.

When a seal is under negative pressure, it can create a vacuum effect that can lead to the drawing in of contaminants or fluids from the external environment if the seal is not designed to handle this pressure differential effectively. This contrasts with other scenarios, such as a seal being fully sealed or experiencing a leak, where the pressure characteristics would differ significantly. Understanding this behavior is crucial for ensuring the proper functionality and integrity of sealed systems.