The general task of the butterfly is to regulate the disc valve. According to the research that was done BVAA, it says that the butter fly valve involves rotation of the obturator at about an axis and flows in the right angle direction. The interesting with this is that the flow of the open position gets its way through the obturator. Normally, the butter fly valve is composed of a plate and a circular disc which are made of the stem that is connected through the middle part of the offset. When opening the disc pivot, it usually rotates 90 degrees within the valve bore. When this happens, it results in it aligning with the flow consequently causing a flow path that is unrestricted. The butterfly valve usually works similar to the ball valve in that they both rotate about 90 degrees and they both allow a quick shutoff.