1. The lifting screw of the dark-rod flange gate valve is only rotating, topless and moving down. The only exposed screw is a rod, and its nut is fixed on the gate plate. The lifting screw of the open rod flange gate valve is exposed, and the nut is attached to the handwheel and is fixed (neither rotating nor axial moving). By rotating the screw, the lifting ram plate is lifted. The screw and the gate plate have only relative rotation movement but no relative axial displacement, and the appearance is a gate bracket. 2. The screw rod cannot be seen in the dark rod valve, while the screw rod can be seen in the open rod. 3. When the valve is switched on, the steering wheel and the stem are connected together and relatively motionless. It is opened and closed by driving the valve disc up and down by rotating the stem at the fixed point. Open stem valves are driven up or down the disc by a screw between the stem and the steering wheel. The simple point is that the open valve is the valve disc connected to the stem to do the up and down movement, the steering wheel is always at the fixed point.