 
 Inlet Spherical Valves are used to ensure a reliable flow shut off under high pressure conditions and usually with lapse of operating power. In particular they are required as turbine guard valves.
Production range:
• Nominal diameter: from 300 to 3000 mm
• Nominal pressure: up to 150 bar
|
Valve components :
• Body and rotor
• Shutter sliding path and counterseats
• Trunnions
|
Materials:
• Carbon steel - Stainless steel
• Stainless steel
• Stainless steel |
|
Spherical Valves
|
 |
|
Applications
• Guard valves for turbines
• Guard valves for pumps
• Guard valves for dissipating and synchronous discharger equipments
|
|
Valve Features:
|
|
• Accurate manufacturing
• High stiffness of structural parts
• Operation under unbalanced pressure
• No specific civil works required
These features give the opportunity to have reliable operations with reduced effort, no leakages and easy maintenance.
|
|
Operational characteristics:
The flow shut off is made in two steps: rotor closure and approaching of the sealing ring. The first operation is usually made by a counterweight or by oil pressure, this can be supplied by the turbine control system or by an independent power unit; the second step is made by the water pressure present in the upstream penstock. A second upstream sealing ring is often provided for maintenance. Friction Loss through the open valve is practically null.
|