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Duo-ChekValves
Specify theDuo-Chek ...to your advantage
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The innovative dual-plate design of
the Duo-Chek employs two spring-
loaded plates (disc halves) suspended
on a central vertical hinge pin. As flow
begins, the plates open in response to
a resultant force (F) which acts as the
center of the sealed surface area. The
contact point of the reactingspring leg’s
force (Fs) actsbeyond the center of the
plate area, causing the heel to open
first. This prevents rubbing of the seal
surface prior to normal plate opening,
eliminatingwear.
As thevelocityofflowdecreases, torsion
spring action reacts automatically. This
moves the plates closer to the body
seats, reducing the distance and time
of travel for closure. By having the
plates closer to the body seats at the
timeof flow reversal, the valvedynamic
response is greatly accelerated. This
dramatically reduces thewater hammer
effect for non-slam performance.
Plates in closed
position.Top view.
Heel opens first as
flow begins.
Plates fully opened (85°)
Plate toe closes first as
flow decreases.
Plates fully seated for
bubble-tight shutoff.
At closing, the point of spring force
causes the toeof theplates toclosefirst.
This prevents dragging of the heels of
the plates and maintains seal integrity
formuch longer periods.
Independent SpringDesign
A springdesignof theDuo-Chek (sizes
6" and larger) allows higher torque
to be exerted against each plate with
independent closing in response to the
processstream.Testinghasproved this
actionprovidesup to25% improvement
in valve life and 50% reduction inwater
hammer.
Eachof thedualplateshas itsownspring
or springs, which provide independent
closing action. These independent
springsundergo lessangulardeflection,
only 140° as compared to 350° for
conventional springswith two legs.
Independent
PlateSuspensionDesign
The Duo-Chek unique hinge design
reduces friction forces by 66%, which
improves valve response significantly.
Support sleeves are inserted through
the outboard hinges so that the upper
hinge is independentlysupportedby the
lowersleeveduringvalveoperation.This
allows both plates to close at the same
time for quick response, and excellent
dynamic performance.
Leadingengineeringspecifiersspecify theDuo-Chek forcheckvalveapplicationsbecause itprovides
high performance.Extensive research and testingwith demonstrated performance has earned
worldwide recognition, unmatched in the industry.
TheDuo-Chekwafer valvedesign is generally stronger, lighter, smaller,moreefficient
and less expensive than conventional swing check valves. Its designmeetsAPI 594
which is approximately one fourth the face to face dimension and 15% to 20% the
weight,onmostpopularsizes,making them lessexpensive thanaswingcheckvalve.
It ismuch easier to install between standard gaskets and line flanges.The savings
compoundduring installationdue toeaseof handlingandonlyoneset of flangestuds
is required.Therefore, it ismore cost effective to install, and also tomaintain.
The Duo-Chek also offers special design features that make it a high performance non-slam check valve.These include a
scrub-freeopening, and inmost sizes aunique independent springdesignaswell as an independent plate support system.
These featuresmaynot be found inother check valves.Other configurationsoffered include lug, double flangeandextended
body.
