Product description:
ASME B16.34,ISO 17292 design standard
Features:
Blow-out Proof Stem
The lower end of the stem is T-shaped structured, protected
by boss of body, which assures stem retention at any
pressure and acts as backseat.
Anti-static Device
A spring-loaded plunger fitted on stem keeps constant
contact between ball, stem and body to create an electric
path to transfer charges, avoiding acceleration of static
electricity as a result of friction during valve on-off. Such
build-up is utterly hazardous to some services.
Fire Safe - Metal to Metal Sealing
When soft seats are decomposed or ruined by fire, the ball,
driven by pressure, comes into contact with the metal lip seal
seat of original soft seat, creating a metal-to-metal seal to
shut off service fluids and minimize internal leakage.
Additionally, the fire safe metal seat prevents damage the
medium imposed on soft seat and minimizes creep of nonmetal
materials. All the Cowinns floating valves are designed to be fire
safe per API 607 and are tested and certified by the third party
Roughness control over stem and packing
Stem surface roughness is strictly restricted between
Ra0.4 and Ra0.8, which ensures entry of graphite
packing powder into tiny stem scratches to function as a
lubricator, minimizing leakages around stem. Max.
roughness of stuffing box is RA3.2, which is a proper
value to hold packing ring in place and result in better
sealing performance
Low Emission Packing
The packing is combination of parallel and vertical layer
which is made of die-formed graphite ring processed by
flexible graphite, characterizing heat resistance, less
stress relaxation and low creep. The special structure
means low friction on rotary stem, providing stabilized
seal capability for the valve for a long time under frequent
functioning.
For low-temperature and cryogenic service, the standard
V shape PTFE packing rings are installed for low
emission control.