PRESSURE TRAP B VERSUS D LIP U-SEALS

摘要

What is the difference between a "B" lip u-seal and a "D" lip u-seal? When do you use one style and when should you use the other? Before we discuss the two styles of u-seal lips, let's briefly look at the evolution of the u-seal and how different lip styles came about. The u-seal shape evolved from the vee ring. Initially the u-seal was a vee ring with a flat back or heel, and all u-seals were symmetrical in shape. Gradually the shape evolved, and instead of a sharp-pointed lip design, the "D" lip style was used on all u-seals to improve sealing effectiveness. In the late 1950s, a major seal manufacturer introduced the bevel lip or "B" lip design. The characteristics of the "B" lip and the new geometry of the u-seal created a more effective seal.