  Butterfly valves are used in all applications requiring a reliable shut off of pipings in any working condition and in particular where an emergency closure is required with no energy.
Production ranges:
• from 300 to over 6000 mm nominal diameter
• from 1 to 25 bar nominal pressure
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Valve components :
• body and disc
• sealing counterseats on the body
• seals
• pins
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Materials:
• Welded steel - Ni-resist cast iron
• Stainless steel lined with vulcanized neoprene
• Neoprene, special shapes
• High tensile steel - Stainless steel
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Butterfly Valve
Valve 5250 mm Dia, 6 bar
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Sezione di valvola a farfalla - Angolo di chiusura 90°
Section of butterfly valve - 90° closure angle
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Sezione di valvola a farfalla - Angolo di chiusura 80°
Section of butterfly valve - 80° closure angle
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Applications
• Guard valves for penstocks
• Guard valves for turbines
• Guard valves for pumps
• Shut off valves for cooling systems
• Shut off valves for aqueducts
• Shut off valves for irrigation systems
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Features of Calzoni' s Butterfly Valves
• 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 and maximum sensitivity; no leakages, and easy maintenance; installation in areas far from the guard house.
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Operational characteristics:
The disc, which is controlled by the actuator, closes the opening by rotating around its pins thus allowing to adjust the the flow rate and to shut off the fluid. The operation in guard valves is by hydraulic control in opening and by conterweight in closure. The operation in shut off valves is by hydraulic, electromechanical, manual control in both opening and closure.
Two different constructive solutions for disc closure can be adopted:
- closure with 90° angle
- closure with 80° angle
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