Globe valves and gate valves are two types of valves that are widely used. Below, we will introduce the detailed differences between globe valves and gate valves with reference to the technical data of COVNA.

The working principles are different. The stop valve is of the rising stem type, with the handwheel rotating and moving up along with the valve stem. For the gate valve, the handwheel rotates and the valve stem moves up. The flow rates are also different. The gate valve requires full opening, while the stop valve does not. The gate valve has no requirements for the direction of the inlet and outlet, but the stop valve has specified inlet and outlet directions. The inlet gate valve and the stop valve are both shut-off valves and are the two most common types of valves.

2. In terms of appearance, gate valves are shorter and taller than globe valves, especially the open stem type which requires a relatively high height space. The sealing surface of a gate valve has a certain self-sealing ability. Its valve core is tightly pressed against the sealing surface of the valve seat by the medium pressure, achieving a tight seal without leakage. The slope of the valve core of a wedge gate valve is generally 3 to 6 degrees. When it is forcibly closed too much or when there is a large temperature change, the valve core is prone to getting stuck. Therefore, high-temperature and high-pressure wedge gate valves all adopt certain structural measures to prevent the valve core from getting stuck. When a gate valve is opened or closed, the sealing surface of the valve core and the valve seat are always in contact and rub against each other, thus the sealing surface is prone to wear. Especially when the valve is in a nearly closed state, the pressure difference before and after the valve core is very large, and the wear of the sealing surface becomes even more severe.

Compared with the inlet globe valve, the main advantage of the gate valve is that it has a smaller fluid flow resistance. The flow resistance coefficient of a common gate valve is approximately 0.08 to 0.12, while that of a common globe valve is about 3.5 to 4.5. It requires less force to open and close, and the medium can flow in both directions. However, its disadvantages include a complex structure, larger height dimensions, and the sealing surface is prone to wear. The sealing surface of the globe valve must be forced to close to achieve a seal. Under the same diameter, working pressure, and the same driving device, the driving torque of the globe valve is 2.5 to 3.5 times that of the gate valve. This point should be noted when adjusting the torque control mechanism of the imported electric valve.

4. The sealing surfaces of a globe valve only come into contact when it is fully closed. The forced closing of the valve core results in a very small relative sliding distance with the sealing surface, thus causing minimal wear on the sealing surface. The majority of wear on the sealing surface of a globe valve is due to debris between the valve core and the sealing surface or the non-tight closure state, which leads to high-speed erosion by the medium. When installing a globe valve, the medium can enter from either below or above the valve core. The advantage of the medium entering from below the valve core is that when the valve is closed, the packing is not under pressure, which can extend the service life of the packing and allow for packing replacement while the pipeline before the valve is under pressure. The disadvantage of the medium entering from below the valve core is that the driving torque of the valve is relatively large, approximately 1.05 to 1.08 times that of entering from above, and the axial force on the valve stem is greater, making the valve stem more prone to bending. Therefore, the medium entering from below is generally only suitable for small-diameter manual globe valves, with the force exerted by the medium on the valve core when the valve is closed not exceeding 350 kg. Imported electric globe valves typically use the medium entering from above. The disadvantages of the medium entering from above are exactly the opposite of those from below.

5. Compared with gate valves, globe valves have the advantages of simple structure, good sealing performance and convenient manufacturing and maintenance; however, they have the disadvantages of high fluid resistance and large opening and closing force. Both gate valves and globe valves are fully open or fully closed type valves, used for cutting off or connecting the medium, and are not suitable for use as inlet regulating valves. The application scope of globe valves and gate valves is determined by their characteristics. In smaller channels, when better shut-off sealing performance is required, globe valves are often used; in steam pipelines and large-diameter water supply pipelines, where fluid resistance is generally required to be small, gate valves are used.