Applicability of globe valves

适用性球阀

A globe valve is a valve in which the closing member (valve flap) moves along the centerline of the valve seat. According to this form of movement of the valve flap, the change of the valve seat orifice is proportional to the valve flap stroke. Since the stem opening or closing stroke of this type of valve is relatively short and has a very reliable shut-off function, and since the change in the seat orifice is proportional to the travel of the valve flap, it is very suitable for regulating the flow rate. Therefore, this type of valve is very suitable for cutting off or regulating and throttling.

Once the globe valve flap is removed from the closed position, its seat and flap sealing surfaces no longer come into contact with each other, resulting in minimal mechanical wear and tear on the sealing surfaces, leading to excellent sealing performance. The drawback is that the sealing surfaces may get trapped between particles in the flow medium. However, this issue can be resolved by using a steel ball or porcelain ball as the valve flap. Most globe valves are relatively easy to repair or replace the valve seat and flap, and the sealing element can be repaired or replaced without dismantling the entire valve from the pipeline, making it suitable for occasions where the valve and pipeline are welded together.

The minimum flow resistance of globe valves is also higher than that of most other types of valves because of the change in the direction of flow of the medium through such valves. However, this situation can be improved depending on the structure of the valve body and the layout of the valve stem relative to the inlet and outlet channels. At the same time. As the globe valve flap open and close between the stroke is small, the sealing surface can withstand multiple opening and closing, so it is very suitable for the need for frequent switching occasions. Globe valve can be used in most media flow system. Has been developed to meet the petrochemical, electric power, metallurgy, urban construction, chemical industry and other sectors of various uses of various forms of globe valve.

The use of globe valves is extremely common, but due to the larger opening and closing torque and longer structure length, the nominal diameter is usually limited to below 250mm, with some up to 400mm. Special attention is required for selecting the import and export direction. For cut-off valves with a nominal diameter below 150mm, the media mostly enters from the bottom of the valve flap, while for those above 200mm, the media mostly enters from the top of the valve flap. This consideration is made to account for the closing torque of the valve. To reduce the opening or closing torque, bypass or external bypass valves are generally installed within globe valves above 200mm.