Different flow resistance: the flow resistance of the gate valve is smaller than that of the globe valve, the medium channel inside the valve body is straight through, and the medium flows in a straight line; compared with the globe valve, it saves effort when opening and closing. The installation direction is different: the gate valve can be installed horizontally or vertically without changing the flow direction of the medium; the ball valve is generally installed horizontally; the globe valve can be used to change the direction of installation. The so-called dark valve is actually a dark stem valve, corresponding to the bright stem valve, which is a classification in the gate valve. The gate valve of the gate valve moves in a straight line with the valve stem, which is called a rising stem gate valve, while the nut of the valve stem of some gate valves is set on the gate plate. So it is called dark rod valve.
