Approach to a correct function of stuffing boxes
- GKN Gemeinschaftskernkraftwerk Neckar, Neckarwestheim (Germany)
- AMTEC Advanced Measurements, Leinfelden (Germany)
Stuff boxes are often used to tighten the gaps between valve stems and the housing. The stuffing box packing material is compressed axially to achieve a radial stress value, which is necessary for tightness. Tightness is achieved, if the sealing materials are seated properly and if a sufficient stress value is acting in radial direction during all states of operation. High prestress values are necessary for tightening purposes, lower values are better for the function of the valve. As the seating and the prestressing force is applied axially (using the bolts of a gland), gasket factors must be known, that characterize the deformation behavior and the transmission (relation between radial/axial stress). Furthermore, gasket factors, that characterize the tightening behavior, are necessary. Such gasket factors give the relation between radial stress and leakage of the packing materials. A friction coefficient -- this parameter determines the function of the valve (together with the radial stress) -- is another important gasket factor. Additionally the relaxation of the stuffing box packing material between the assembly and the operating state must be known. In the paper definitions for the most important gasket factors of stuffing box materials are provided. Test procedures and test rigs for the determination of the gasket factors are discussed. Gasket factors, which have been measured with these newly developed test rigs, are related to experiences with real applications. Finally a method for a controlled prestressing of gland packings is described.
- OSTI ID:
- 404154
- Report Number(s):
- CONF-960706-; ISBN 0-7918-1773-3; TRN: 97:000389
- Resource Relation:
- Conference: American Society of Mechanical Engineers (ASME) pressure vessels and piping conference, Montreal (Canada), 21-26 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Computer technology -- 1996: Applications and methodology. PVP-Volume 326; Hulbert, G.M. [ed.] [Univ. of Michigan, Ann Arbor, MI (United States)]; Hsu, K.H. [ed.] [Babcock and Wilcox, Barberton, OH (United States)]; Lee, T.W. [ed.] [FMC Corp., Santa Clara, CA (United States)]; Nicholas, T. [ed.] [USAF Wright Laboratory, Wright-Patterson AFB, OH (United States)]; PB: 217 p.
- Country of Publication:
- United States
- Language:
- English
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