This type of valve is for opening and closing. It is permanently installed on the inlet and outlet of cold and heat sources, the inlet and outlet of equipment, and the branch lines of pipelines (including standpipes). It can also be used as a water release valve and a gas release valve. Common shut-off valves include gate valves, globe valves, ball valves and butterfly valves.
Gate valve can be divided into open rod and dark rod, single gate and double gate, wedge gate and parallel gate, etc. The closing tightness of the gate valve is not good, and the gate valve with large diameter is difficult to open; the size of the valve body along the direction of water flow is small, the flow resistance is small, and the nominal diameter of the gate valve span is large.
According to the flow direction of the medium, the globe valve is divided into three types: straight-through type, right-angle type and direct-current type, and there are open rods and dark rods. The closing tightness of the globe valve is better than that of the gate valve, the valve body is long, the flow resistance is large, and the maximum nominal diameter is DN200.
The valve core of the ball valve is a round ball with a hole. When the valve stem is moved by the plate, it is fully open when the opening of the sphere is facing the axis of the pipeline, and fully closed when it is rotated 90°. The ball valve has a certain adjustment performance and is closed more tightly.
The valve core of the butterfly valve is a circular valve plate, which can rotate along the vertical axis perpendicular to the axis of the pipeline. When the plane of the valve plate is consistent with the axis of the pipe, it is fully open; when the plane of the gate plate is perpendicular to the axis of the pipe, it is fully closed. Butterfly valve body length is small, flow resistance is small, and the price is higher than gate valve and globe valve.
