Butterfly valves are valves fitted with a disc shutter that rotates around a normal axis in the direction of the pipe where they have been installed. The role of the valves is to intercept or divide the flow of the fluid/gases conveyed. In particular, butterfly valves are used when exact precision is not needed and a limited load loss is required.
Butterfly valves are mainly made up of a valve body, usually made of cast iron (grey or ductile) or stainless steel (CF8), by a disc shutter (stainless steel or other materials) that can rotate around an axis diameter, thus reducing the flow section until closure, and by a sealing seat.
You can opt for either the soft sealing seat, made up of an elastomer (PTFE NBR EPDM) which ensures a grade A degree of loss in line with UNI EN 12266-1 or, in the case of more severe temperature conditions or due to the flow of corrosive fluids, the metal (stainless steel) seal solution can be adopted that has a degree of loss lower than 1% of the flow.
Butterfly valves are most commonly used in processing plants and the distribution of process fluids in industrial, agricultural and agri-food applications for water heating, cooling and fire prevention and naval systems.
Butterfly valves are split into two groups: the LUG series and WAFER series. The LUG type series has threaded projections in the valve body which allow for fastening between the flanges by the use of screws. The advantage of the LUG type is that the valve can also be installed at the end of the pipe. The WAFER type series has four centering slotted wings formed on fusion (two upper and two lower) that make the valve suitable for installation in-line between the two flanges.
Butterfly valves can be manual with lever control or motorised thanks to pneumatic actuators or electric servomotors. The motorised valves can be fitted with pneumatic or electropneumatic positioners, using the limit switches and/or inductive or magnetic sensors.