In a mechanical seal, which component helps maintain contact between the sealing faces?

• A. The lubrication reservoir
• B. The spring
• C. The pump casing
• D. The discharge check valve

Answer: (B)

The spring is what keeps the sealing faces pressed together. It provides a constant preload that pushes one face toward the other, ensuring contact even as the shaft moves slightly, or as fluid pressure and temperature change. This contact is essential to form and maintain the seal and prevent leakage.

The lubrication reservoir’s job is to supply lubricant to minimize wear and reduce friction between the faces; it doesn’t actively press the faces together. The pump casing is simply the housing that contains the seal, not the force that maintains contact. The discharge check valve controls flow direction and backflow prevention, but it does not influence the contact force between the sealing faces.