进口闸阀的启闭件是闸板，可用于控制空气、水、蒸汽、各种腐蚀性介质、泥浆、油品、液态金属和放射性介质等各种类型流体的流动。闸板的运动方向与流体方向相垂直，进口闸阀只能作全开和全关 , 不能作调节和节流。闸板有两个密封面， 比较常用的模式闸板阀的两个密封面形成楔形、楔形角随阀门参数而异 。闸阀驱动方式分类：手动闸阀，气动闸阀，电动闸阀。
The gate valve is used to control the flow of air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. The movement direction of the gate is perpendicular to the direction of the fluid. The inlet gate valve can only be fully opened and fully closed, and can not be adjusted and throttled. There are two sealing surfaces on the ram. The two sealing surfaces of the most commonly used ram valve form wedges, and the wedge angle varies with the valve parameters. Gate valve driving mode classification: manual gate valve, pneumatic gate valve, electric gate valve.
The basic working principle of the import gate valve is as follows:
一 . 进口闸阀关闭程序：
1、 Inlet gate valve closing procedure:
1. In the last few turns of the hand wheel, the angle plane at the bottom of the valve stem mechanically wedges against the ball to press it tightly on the valve seat,
Complete sealing is achieved.
2. when the valve is closed, rotate the hand wheel clockwise, and the valve rod starts to lower and the ball starts to rotate when it leaves the valve seat.
3. Continue to rotate the handwheel, and the valve rod is affected by the guide pin embedded in the spiral groove on it, so that the valve rod and the ram rotate 90 ° at the same time.
4 the brake body has rotated 90 ° without contact with the valve seat when it is about to close.
2、 Opening procedure of inlet gate valve:
1 until it reaches the full open position, the valve rod is lifted to the limit position, and the ball rotates to the full open position.
2 in the closed position, the valve body is pressed on the valve seat by the [wiki] mechanism of the valve stem.
3 when the hand wheel is turned counterclockwise, the valve rod moves in reverse direction, and the angle plane at the bottom of the valve rod makes the ball free from the valve seat.
4. The valve rod continues to lift and interacts with the guide pin in the screw groove of the valve rod, so that the ball starts to rotate without friction.