Globe Valves
Globe valves use a plug- or cone-shaped disc that moves along the seat centreline to open, close and throttle. The sealing surfaces are flat or conical with a narrow contact band, which seals reliably and is easy to lap during maintenance. Compared with a gate valve the flow path is S-shaped and resistance is higher, but the valve offers some throttling capability, making it suitable for small- and medium-bore lines where both tight shutoff and regulation matter. By flow pattern there are straight-through (T-pattern), angle (90°) and Y-pattern (straight-flow) designs. A Y-pattern valve has roughly one third the resistance of a straight-through type and suits high-viscosity and high-velocity media. The angle type combines valve and elbow functions and suits high differential pressure with solids. The bellows-sealed globe valve uses a metal bellows as the primary seal with packing as a secondary barrier, eliminating stem leakage at source; it is used specifically for toxic, flammable and volatile media. Pressure ratings cover ASME Class 150–2500 (PN 20–PN 420). Body materials include WCB, WC6/WC9 and CF8/CF8M. Sealing surfaces follow API trim numbers such as 13Cr (Trim 1), Stellite 6 (Trim 5) and Monel (Trim 8). Design and manufacture follow API 623, GB/T 12235 and ASME B16.34; low-fugitive-emission versions can be supplied to ISO 15848-1 classes.
Bellows-Sealed Globe Valve
The bellows-sealed globe valve places a metal bellows between the stem and the body as the primary seal, completely isolating the medium in the stem movement area from the outside. Together with graphite packing it forms a dual seal that eliminates external leakage at the packing, making it a critical valve for conveying toxic, flammable, volatile and valuable media. The bellows is made of corrosion-resistant materials such as 316L/Inconel and passes helium mass-spectrometer leak testing. Combined with an anti-blowout stem and live-loaded packing, low fugitive emission designs can be supplied to the classification requirements of ISO 15848-1. It is widely used in steam, heat-transfer oil, ammonia, chlorine and hazardous chemical lines.
Y-Pattern Globe Valve
The Y-pattern globe valve (also called straight-through or oblique-stem globe valve) has its stem set at an angle to the body bore axis, so the medium passes through almost in a straight line and the flow resistance is only about one third that of a straight-through globe valve. It combines the sealing performance of a globe valve with flow resistance close to that of a gate valve. It is suitable for media that are highly viscous, high-velocity, prone to crystallisation or contain a small amount of solids, such as steam, heat-transfer oil and slurry lines, where it serves for shutoff and regulation. It is a common valve type for high-temperature, high-pressure steam blowdown and condensate systems.
Angle Globe Valve
The angle globe valve has its inlet and outlet arranged at a 90° right angle, so the medium changes direction once inside the valve. The design is compact and can replace a pipe elbow directly, reducing fittings and welds. The seating surface is usually hardfaced with a hard alloy, which suits media with high differential pressure, solids content or a tendency to coke, such as black water in coal chemical plants, coking units and high-pressure blowdown lines. Vertical installation keeps material from accumulating inside the valve and allows complete draining.
Flanged Globe Valve
The flanged globe valve opens, closes and regulates flow by lifting a plug-type disc along the seat centreline; the seating surfaces are a flat or conical pair, giving reliable sealing and easy maintenance. Compared with a gate valve, the flow passage of a globe valve is S-shaped, so flow resistance is higher, but the valve offers a degree of flow regulation. In the standard straight-through design, the body is usually closed by a bolted flanged bonnet, and the seating surface can be hardfaced with 13Cr (Trim 1), Stellite 6 (Trim 5) or Monel (Trim 8) to suit different media. It is used in small-bore steam, water and oil lines where tight shutoff and throttling are required.