The opening and closing element of an API globe valve is a plug-shaped disc with a flat or conical sealing surface; the disc moves linearly along the centerline of the fluid flow. These valves rely on stem pressure to press the disc's sealing surface tightly against the seat's sealing surface, thereby blocking the flow of the medium; they are classified as forced-sealing valves. Based on their structural design, API globe valves are primarily categorized into three types: straight-through, angle, and oblique (Y-pattern) valves.
The closing mechanism of API globe valves dictates that they allow flow in only one direction, requiring specific orientation during installation. Compared to gate valves, API globe valves have a longer face-to-face dimension and offer higher fluid resistance. However, they experience less friction between sealing surfaces during operation, resulting in greater durability. With a short disc travel distance, ease of manufacturing, and convenient maintenance, they are suitable for low-to-medium pressure applications as well as high-pressure environments.
Regarding sealing technology, the sealing surfaces of the disc and seat are hard-faced with Stellite cobalt-based alloys of varying hardness levels. This provides outstanding advantages, including reliable sealing, high hardness, and resistance to wear, high temperatures, corrosion, and galling, all contributing to a long service life. The valve stem undergoes quenching and tempering or integral forging processes, further enhancing the valve's durability.
API globe valves are widely used in piping systems across industries such as petroleum, chemicals, pharmaceuticals, power generation, metallurgy, and textiles. Suitable media include water, oil, steam, acidic fluids, and various corrosive liquids. They offer flexible operation methods, including manual, gear-driven, electric, and pneumatic actuation. Unlike API 6D check valves, which operate automatically, API globe valves require external force to achieve a forced seal; furthermore, compared to the full-open/full-close function of API 600 gate valves, API globe valves excel at flow regulation and shut-off operations. It is this unique functional role and superior sealing performance that make API globe valves one of the most widely used shut-off valves in industrial piping systems.
