Flowserve Nordstrom Dynamic Balance Plug Valve and Double DB Plug Valve - Manual (Page 15)

Flow Control
Nordstrom Valves
FCD NVENIM2005-01 Dynamic Balance ® Plug Valve and Double DB ® Double Isolation Plug Valve 15
5.13 Valve Front Identification
This manual periodically refers to the valve front. The front of the
valve has the following in common:
• Nameplate
• Sealant Injection Fitting
• Handwheel (gear-operated only)
NOTE: See the Technical Data section for a parts list and exploded
views of typical wrench-operated Dynamic Balance Plug Valves.
5.14 Gearing
Simple or single reduction, worm gearing, and compound bevel
worm gearing are used on Dynamic Balance Plug Valves.
All gear mechanisms are enclosed in weatherproof housings and are
packed with gear grease.
A Position Indicator, mounted on the upper end of the gear segment,
aligns with the Plug Port to provide a visible means of determining
the Plug Port position in relation to the flow line of the valve.
During operation, all parts of the gearing have free movement.
5.15 Sealants
Valve sealant is a viscous material that resists chemical attack and
the dissolving characteristics of line media. Sealant performs four
functions in a lubricated Plug Valve:
1. Drop-Tight Seal. To secure an absolutely tight seal, the film of
sealant works to form a seal between the Body and Plug. This
seal is formed by sealant transmitted in a system of grooves
around each port. With proper selection of sealant for your par-
ticular service, this tight seal can be retained over a wide range
of temperatures and pressures.
2. Lubrication. A protective film of sealant prevents metal-to-metal
contact of the bearing surfaces of the valve by filming over bear-
ing surface irregularities. The film of sealant permits the Plug
and Body of a Plug Valve to glide smoothly against each other,
allowing the valve to operate easily.
3. Renewable Seat. Sealant is a structural part of the valve that
provides a flexible and renewable seat. To repair the seats, it is
not necessary to disassemble the valve or remove it from the
line. Injection of sealant is all that is required.
4. Plug-Jacking. The fundamental operating principle of the
Nordstrom Plug Valve design is the application of Pascal’s Law.
Sealant, under pressure developed by the injection mechanism,
supplies the hydraulic means for lifting the Plug from its tapered
seat in the valve Body, thus allowing the Plug to float freely in
the Body and allow easy operation.
A regularly scheduled sealant injection program enables the Dynamic
Balance Plug Valves to operate more easily and extends the service
life of the valves. For more information on sealant injection, refer to
section 5.18.
Flowserve Sulphur Springs supplies many different types of sealant
for use in Plug Valves. When selecting Sealant for your specific
services, refer to the Nordstrom Valve Sealants brochure or consult
your Flowserve customer service representative.
5.16 VXX Valve Purge
VXX Valve Purge, a non-hazardous formulation, was developed for
cleaning valves in-line, returning them to service without disassem-
bly, and eliminating down time. Periodic injection of sealant into a
valve flushes debris from the sealant system and allows sealant to
flow more freely. See the procedures in Problem C of section 6.
5.17 Sealant Injection Equipment
Flowserve Sulphur Springs offers five types of heavy-duty valve seal-
ant injection equipment, designed to correspond to the type of use
and amount of sealant needed:
1. 400-D Hydraulic Hand Gun. Uses J Stick sealant and Gun Pak
sealant.
2. Hypregun-Plus 5Q. Uses a 5-quart can of sealant.
3. Hypregun-Plus 5G. Uses a 5-gallon pail of sealant.
4. 400-A Screw Prime Hand Gun. Uses K Stick sealant and Car-
tridge sealant.
5. 400-B 5 Gallon Bucket Pump. Uses a 5-gallon pail of sealant.
For additional information about Nordstrom Sealant Injection
Equipment, refer to the appropriate Nordstrom Sealant Injection
Equipment brochure.