Fixed cone valves are mostly used to regulate flow
from dams, clear-water reservoires, barrages or storages basins. It is also a
free discharge valve that is commonly used as a turbine bypass valve, reservoir
drain or continuous discharge flow control valve.
Discharges of large water flow rates under high
pressure conditions demands an efficient conversion of energy. Any damages due
to cavitation and any risk to the structure due to vibrations and oscillations
have to be avoided. Fixed cone valve has a fixed cone with contoured ribs that
eliminate the vibration problems associated with other fixed cone designs. Flow
is controlled by movement of an external stainless steel gate which has a drip
tight metal to metal shut off. When discharging into the atmosphere, the jet
spreads out in a wide cone angle and breaks up into a fine spray. If
containment of the jet is desired, a hood can be installed which concertrates
the flow.
Fixed cone valve is
composed of actuator units, drive mechanism, welded steel construction with
nitronic 60 pads, sleeve gate, rubber seal, nitronic 60 seat, contour ribs and
optional hood. Spray piece is supported and connected by the fixed cone and the
contour ribs. There is an open section between the spray piece and the welded
steel body. Sleeve gate is installed outside of the spray piece and the
movement of the sleeve gate can change the free discharge
(free spray) area. A hood can be installed for some application needs and this
hood can confine the flow to a smaller area which can avoid the spray of the
flow and cavitation damage to the line.
Hooded fixed cone valves are mostly used in inline installation applications.
Unhooded fixed cone valves are mostly used as discharge valves to release
pressure, retain pressure or control the flow in the pipe line.