  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 ranges:
• from 300 to 3000 mm nominal diameter
• to 150 bar nominal pressure
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Valve components :
• body and rotor
• shutter sliding path and counterseats
• trunnions
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Materials:
• Carbon steel - Stainless steel
• Stainless steel
• Stainless steel |
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Spherical Valves
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Applications
• Guard valves for turbines
• Guard valves for pumps
• Guard valves for dissipating and synchronous discharger equipments
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Features of Calzoni' s Inlet Spherical Valve
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• Accuracy of machinings
• High stiffness of structural parts
• Operation under unbalanced pressure
• No specific civil works requird
This allows to have a reliable operation with reduced effort, no leakages and easy maintenance.
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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. The head losses through the open valve are practically null.
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