Experimental Study of Leakage and Friction of Rectangular, Elastomeric Hydraulic Seals for Reciprocating Motion from −54 to +135°C and Pressures from 3.4 to 34.5 MPa

Abstract

Hydraulic seals for reciprocating motion are used in mechanisms, machines, and devices most commonly in automotive, aerospace, marine, and general industrial sectors. Applications vary from those of a cheap medical injector and tire pump to mechanisms controlling ultra-expensive equipment in power stations, ships, and space vehicles. Unfortunately, elastomeric seals are flexible solids with nonlinear response to changes in their environment involving stress or strain, heat transfer, interaction with fluids, and aging. Unsurprisingly, research into their performance is ongoing for more than 80 years. The present experimental study is a step toward a better understanding of sealing performance in a broad range of temperatures and sealed pressures. Hundreds of experiments were conducted in conformance to international standards and in controlled conditions within tight tolerances of all parameters, including mechanical properties, solid dimensions, and operating conditions. Rectangular elastomeric seals for aerospace applications were studied under sealed pressures of 3.4 to 34.5 MPa (500 to 5,000 lb/in2) and in ambient temperatures of −54 to +135°C. The combined range of pressures and temperatures exceeds what is available in the literature, particularly on the low temperature side. Other parameters varied in the experiments include the seal dimensions and radial interference, the surface roughness of the cooperating shafts, and the support of seals by one or two back-up rings. The results of the parametric study, summarized in eight tables and two figures, have been sorted for ascending leakage and friction force at each of the studied ambient temperatures for quick selection of optimal values.