Structurally: The face to face of the gate valve is shorter than globe valve, the height is higher than the globe valve. The installation of the rising stem gate valve should pay attention to the height. This should be paid attention to when the installation space is limited. The gate valve can be tightly closed with the sealing surface by the medium pressure, to make sure no leakage. When opening and closing, the valve core and the valve seat sealing surface are always in contact and rub against each other, so the sealing surface is easy to wear. When the gate valve is close to closing, the pressure difference between the front and rear of the pipeline is large, which makes the sealing surface wear more seriously. In principle: The globe valve is of a rising stem type, and the handwheel rotates and rises together with the stem. The gate valve is rotated by the handwheel, and the valve stem moves upward. Flow rates vary, gate valves require fully open or fully closed, and globe valves do not. Globe valves have specified inlet and outlet directions; gate valves do not have requirements for inlet and outlet directions.
From flow up: The globe valve is low in and high out, and it is obvious from the outside that the pipeline is not on the horizontal line of one phase. The gate valve flow channel is on a horizontal line. The stroke of the gate valve is larger than that of the globe valve. From installation: The flow direction of the gate valve is both sides. There are two ways to install the globe valve. One is that the medium can enter from the bottom of the valve core. Under the circumstance, the replacement of the packing is carried out; the disadvantage is that the driving torque of the valve is large, which is about 1 times that of the upper flow, the axial force on the valve stem is large, and the valve stem is easy to bend. Therefore, this method is generally only suitable for small-diameter globe valves (below DN50), and the globe valves above DN200 use the method that the medium flows in from above. (The electric globe valve generally adopts the way of entering the medium from above.) The disadvantage of entering the medium from the top is just the opposite of the way of entering from the bottom.
From the sealing surface: The sealing surface of the globe valve is a small trapezoidal side of the valve core (specifically depends on the shape of the valve core). Once the valve core falls off, it is equivalent to the valve closing (if the pressure difference is large, of course, it is not tightly closed, but the anti-reverse effect is not bad). The gate valve is sealed by the side of the valve core gate, and the sealing effect is not as good as that of the globe valve, and the valve core will not be closed like the globe valve.
