Performance and Behavior of Seals for Pneumatic Spool Valves

Abstract

This article presents a seal development approach that takes actual operating conditions (mounting, sealed pressure, lubricating conditions), seal material, and counterpart machining tolerances into account. The approach was applied to the design of seals for a commercial pneumatic spool valve. A single seal geometry and two seat configurations were specified on the basis of finite element analysis and experimental tests. The goal was to develop a compact low-friction seal capable of operating dry in order to avoid the use of grease. The investigation focused on seals that are somewhat shorter (i.e., with a smaller radial height to permit application on new valve models) than existing commercial units but whose performance is not inferior. Prototypes of the new seal were manufactured and tested, and a specific device for measuring seal friction force and sealing was developed. The existing commercial seal was also investigated. The commercial seal and the proposed new designs were then compared.

KEY WORDS:

• Seal Design
• Sealing Systems
• Spool Valves
• Friction
• Pneumatics

ACKNOWLEDGEMENTS

This work was supported by European Community funds as part of the FP6 KRISTAL project. The authors thank Camozzi S.p.A. and FBJ Rubber for providing material under test and prototypes.

Review led by Jim Netzel