[Shutoff valve advantages]: (1) cut-off valve structure simpler than the gate, manufacturing and maintenance are more convenient. (2) sealing surface easy to wear and abrasion, sealing, and no relative sliding between the valve and the valve sealing surface when opening and closing, and thus wear and scratches are not serious, good sealing performance and long service life. (3) When opening and closing, the valve stroke is small, and thus the height of the cut-off valve is smaller than the gate, but the gate is longer than the length of the structure. (4) The opening and closing torque, the more laborious opening and closing, opening and closing time principal. (5) Fluid resistance, due to the valve body media path more tortuous, large fluid resistance and power consumption. (6) Nominal flow direction of medium PN≤16MPa, generally used downstream, medium upstream direction from the valve; when nominal PN≥20MPa, generally countercurrent, media orientation downstream from the valve. To increase the seal performance. When used, the cut-off valve medium flow in one direction only, you can not change the direction of flow. (7) when fully open valve is often affected by erosion. Cutoff valve installation and maintenance should note the following: 1, cut-off valve hand wheels, handles the operation can be mounted in any position on the pipeline. 2, hand wheels, handles and micro-actuator, do not allow for lifting use. 3, the flow of media should be consistent with the direction indicated by the arrow body.