NCCER Millwright Practice Exam

What type of seal design primarily reduces leakage in machinery?

1. Single-spring seal

2. Double-lip seal

3. Multiple-spring seal

4. Flat seal

The correct answer is: Multiple-spring seal

The multiple-spring seal design is particularly effective in reducing leakage in machinery due to its ability to maintain uniform pressure across the sealing surface. This design typically incorporates several springs distributed around the circumference of the seal, which helps ensure that the sealing lip maintains constant contact with the surface it seals against. As the machinery operates and experiences varying pressures or mechanical movement, the multiple springs can adapt more dynamically compared to other sealing designs, thus preventing leaks more effectively. This feature is crucial in applications where maintaining a tight seal is necessary to avoid the loss of fluids or gases, which can lead to decreased efficiency or even failure of the machinery. Other seal designs, while they may provide a level of sealing, do not offer the same level of adaptability or pressure distribution as the multiple-spring design, which is why this option is the best choice for minimizing leakage.