Practical Seal Design

Leonard J. Martini, Lynn Faulkner

• Publisher: Routledge
• Year: 2018
• Print ISBN: 9780824771669
• eBook ISBN: 9781351422536
• Topic: Technology & Engineering
• Subtopic: Industrial Design
• Index: Technology & Engineering

This compact, on-the-job handbook provides all the practical and theoreticalinformation to design elastomeric O-ring seals for the full range of static,reciprocating, and rotary functions.Complete with fully illustrated, detailed examples to guide you step-bystepthrough virtually every seal design situation, Practical Seal Designprovides thorough coverage of ring seal geometry, material-compoundcapability, material performance, and design methods ... detailed designconsiderations including stretch, swell, shrinkage, and blowout prevention,as well as innovations to extend seal life span and minimize systemhysteresis ... unmatched treatment of piston-cylinder seal and shaft sealdesign ... and clearly elucidated specifications for military, aerospace, andindustrial standards.With quick-access features to facilitate prompt, proper, and effective design,Practical Seal Design is an essential single-source reference for mechanical,manufacturing, industrial, automotive, aeronautical, and ocean engineers.Furthermore, this one-of-a-kind work is an excellent reference text forprofessional seminars on hydrodynamic, pneumatic, and mechanicalengineering systems, and undergraduate mechanical design courses.

II

SPECIFIC APPLICATIONS OF RING SEALS

3

Static and Reciprocating Seal Applications: Clearing up the Confusion Between the Military and Industrial O-Ring Gland Specifications

This chapter discusses the confusion between the military and industrial specifications of O-ring gland designs relative to static and reciprocating seal applications. Confusion between the two specifications is attributed predominantly to the fact that the military specification covers both static and reciprocating seal designs without any distinction within the specification. Because reciprocating seals require less O-ring squeeze than static seals in order to function, the military specification inherently specifies less O-ring squeeze than the industrial static O-ring specification.

The material presented in this chapter should be considered when designing O-ring glands for either static or reciprocating seal applications. Additional information on static seal applications is presented in Chap. 4 and additional information on reciprocating seal applications is presented in Chap. 5.

I. GENERAL AREAS OF CONFUSION BETWEEN MILITARY AND INDUSTRIAL SPECIFICATIONS

As the use of O-ring seals have become more prevalent in mechanical systems, a growing confusing has developed in the minds of designers. This confusion centers around the application of military and industrial specifications in the design of O-ring glands. Both military and industrial design specifications incorporate the same standard-size rubber O-ring seals, but in different ways. For example, a size 116 O-ring in a male gland designed in accordance with the industrial specification will experience a maximum stretch of 5.9%, compared to a maximum stretch of only 2.0% when used in a gland designed in accordance with the military specification.

Table 12. Military Gland Design and O-Ring Selection

*Static applications only.

(1) Inside diameter tolerance for O-rings with inside diameters over $\frac{1}{2}$ in. have been increaed per AS568A.

Source: O-Ring Design and Selection Handbook 110-A, Sargent Industries, Carlabad, Calif., 1976.

Even given the discripancy between the military and industrial specifications, it is up to the designer to determine what specification is applicable to the desired intent of the design. Decisions as to whether a radial gland design is better than a face-seal gland design, when a backup ring should be used, and what is the minimum surface finish required or the proper squeeze can become very confusing when the differences between the two design specifications are not understood. This confusion can be cleared up by analyzing various discrepancies between the military and industrial specifications.

The one major discrepancy that leads to all the confusion between the military and industrial specifications is the fact that ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Figures, Tables, Charts, and Design Examples
• I ELASTOMERIC RING SEALS
• II SPECIFIC APPLICATIONS OF RING SEALS
• References
• Index