Valve stem and packing assembly
- Bingham County, ID
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.
- Research Organization:
- WESTINGHOUSE IDAHO NUCLEAR CO
- DOE Contract Number:
- AC07-84ID12435
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Number(s):
- US 5044606
- OSTI ID:
- 867960
- Country of Publication:
- United States
- Language:
- English
Similar Records
Valve stem and packing assembly
Valve stem and packing assembly
Related Subjects
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/