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Title: Valve stem and packing assembly

Abstract

A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem.more » The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.« less

Inventors:
 [1]
  1. (Bingham County, ID)
Publication Date:
Research Org.:
WESTINGHOUSE IDAHO NUCLEAR CO
OSTI Identifier:
867960
Patent Number(s):
US 5044606
Assignee:
United States of America as represented by United States (Washington, DC) INEEL
DOE Contract Number:  
AC07-84ID12435
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
valve; packing; assembly; provided; rotatable; tractrix; surface; sliding; contact; bonnet; force; applied; means; spring; gland; flange; seals; configuration; serves; create; maintain; reliable; seal; complementary; contacting; combination; serving; journal; bearing; entire; configured; schiele; pivot; proper; alignment; respect; vertical; wear; surfaces; uniform; connected; plug; slip; joint; closed; rotating; compensates; ledge; retaining; nut; bear; prevents; overtightening; resulting; excessive; friction; tractrix surface; proper alignment; valve plug; packing assembly; sliding contact; journal bearing; maintain proper; /277/251/

Citation Formats

Wordin, John J. Valve stem and packing assembly. United States: N. p., 1991. Web.
Wordin, John J. Valve stem and packing assembly. United States.
Wordin, John J. Tue . "Valve stem and packing assembly". United States. https://www.osti.gov/servlets/purl/867960.
@article{osti_867960,
title = {Valve stem and packing assembly},
author = {Wordin, John J.},
abstractNote = {A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1991},
month = {1}
}

Patent:

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