Operation - Emerson Clarkson series Instructions Manual

Clarkson serIes KGF and KGF-HP Slurry valveS
InstallatIon and maIntenance InstructIons
FiGure 3 - OPen POSiTiOn
open position
a) Gate positioned above seals, out of flow.
B) Matching elastomer sleeves seal against
each other under a high compression load.
C) Sleeves act as pressure vessel.
d) no metal parts in contact with slurry.
e) unobstructed port area eliminates
turbulence, minimizes pressure drop
across valve.
F) no seat cavity where solids can collect
and prevent full gate closure.

4 operatIon

1. Clarkson slurry knife gate valves are
suitable for on-off service only. They are
not to be used in a throttling application.
2. To close the valve and provide isolation,
the actuator (handwheel, bevel gear,
air/hydraulic cylinder or electric motor
actuator) moves the metal gate in a linear
motion between the elastomeric sleeves
to shut off the flow. To open, reverse the
operation and the gate moves up and out
from between the sleeves, opening the
valve port.
3. Matching elastomer sleeves seal against
each under a high compression load
when the valve is open, creating the valve
pressure vessel. When the valve is closed,
the sleeves seal against the gate face,
isolating upstream from downstream.
See Figures 3 and 4.
it is normal for the KGF and KGF-HP
to discharge media during opening and
closing cycles. Some additional discharge
may continue for a time after completion
of the open cycle. This helps prevent
any solids from building up between the
sleeves that would prevent a tight seal
when the valve is fully open or closed.
discharge can be controlled with the use of
a splash guard device (refer to section 14).
FiGure 4 - ClOSed POSiTiOn
Closed position
a) Gate travels through sleeves to provide
blind flange shut-off, allowing opportunity
for media to expel to atmosphere.
B) 100% isolation-bubble tight shut-off results
in absolutely zero downstream leakage.
C) When properly installed and maintained,
the KGF is designed to provide
man-safe isolation.
d) double-seated design provides bidirectional
flow and shut-off.
e) Controlled stroke prevents gate from
penetrating too far, minimizing stress
on sleeve.
depending on the pressure rating, some
models of the KGF and KGF-HP include
a splash guard device as standard. do
not install valve over walkways, electrical
or other critical equipment without the
use of a splash guard device or similar
considerations.
4. as the gate strokes, a gap is created
between the facing sleeves, allowing any
media that could potentially clog or jam
the valve to be purged out from between
the sleeves, and potentially expelled
outside the valve housing to atmosphere.
5. The KGF and KGF-HP incorporate a
built-in clean-out area at the base of the
housing assembly. The clean-out area
may be enclosed by a removable splash
guard device. depending on the pressure
rating, some models of the KGF and
KGF-HP include a splash guard device
as standard. This splash guard device
will allow controlled drainage of any
accumulated solids that may prevent full
gate closure. Flush water can be used to
improve the drainage efficiency. With the
splash guard device in place, any solids,
slurry, or flush water ejected from the valve
can be handled in a controlled manner.
See Section 14 for splash guard device
installation instructions.
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