The MBC model FCA butterfly valve is mainly used in strained lines in hydraulic power stations or as a charge or discharge valve and for security purposes in turbines as a shut-off element. It consists of a circular flanged body with a butterfly or disc as a shutting-off element.

The disc is provided with a seal which is fixed to it by a ring in stainless steel material. It is a valve with double eccentricity in the disc. Due to this eccentricity, the friction between the seal and the seat is low and the disc presents a tendency to close the valve.

The most usual device to operate this valve is by means of a hydraulic actuator to open it and an external mechanical drive to close it. The mechanical operation is obtained by a counterweight that guarantees the shut-off in a case of emergency.

The shut-off is also possible with the hydraulic actuator. With the installation of a by-pass, the pressure may be balanced upstream and downstream in order to ease the opening and closing operations. This by-pass consists of a pipe and two small valves: an automatic valve for control and a manual valve for maintenance. Optionally telescopic pipes are installed to help disassemble the valve.