The maximum water head used in butterfly shouldn’t be more than 200m. Compared to other valve types, butterfly valve has small size, light weight, simple structure and easy to operate, but water leakage is large and it makes the hydraulic loss when flow passing the valve.

      Butterfly valve has two types, vertical shaft and horizontal shaft. Vertical shaft is easier to install than horizontal shaft but the underpart is easy to subside sediments and need to clear regularly. So generally choose the horizontal shaft.

 to be continued