Rotary, oscillating & reciprocating seals

In recent years, considerable advances have been made in the prevention of leakage of liquids and oils past moving surfaces. Leakage is the most common source of complaint with regard to hydraulic machinery, in which field the authors have had considerable experience. The subject covers a wide field and, has been limited by excluding hydraulic joints. For the purpose of these papers, a hydraulic seal is defined as one whose function it is to prevent the leakage of liquid between surfaces having relative movement.