Globe Valve

Globe valves are used in piping systems where throttling and frequent operation are required, such as in cooling water, fuel oil, and steam services. They are specified by nominal diameter, pressure rating, end connections, and material of construction. Grades differ by body material (cast iron, carbon steel, stainless steel), trim (disc and seat) material, and compliance with standards like ASME B16.34. They offer better flow control than gate valves but have higher pressure drop. This directory entry covers industrial globe valves as components for machinery and equipment manufacturing. The product is a device that modulates flow in a pipeline. Selection requires defining the nominal diameter (DN 15–400 mm per ASME B16.34), pressure rating (PN 16–40 bar per ISO 7005 or Class 150–300 lb per ASME B16.34), end connections (flanged, threaded, or butt-weld per ASME B16.5 and ASME B1.20.1), and materials of construction. Body materials on file include WCB (cast carbon steel), CF8 (cast stainless steel 304), CF8M (cast stainless steel 316), brass, and cast iron. Trim materials include PTFE for seats and Stellite for wear-resistant surfaces. Operating temperature range for carbon steel bodies is -29 to 425 °C per ASME B16.34. Leakage rate for soft-seated valves can meet Class VI per ANSI/FCI 70-2 with a maximum allowable seat leakage of 0.01 ml/min. Flow coefficient (Cv) ranges from 2.5 to 1200 US gal/min depending on size and design. Face-to-face dimensions for flanged valves are 130–600 mm per ASME B16.10. Stem diameters typically range from 12 to 50 mm. Seat hardness for Stellite overlay is 40–45 HRC. Shell and seat test pressures are 1.5 × PN and 1.1 × PN per ISO 5208, respectively. Internal surface finish for body bore is Ra 3.2–6.3 µm per ISO 1302. Actuation options include manual, gear, pneumatic, and electric. Relevant standards for procurement and verification include ASME B16.34, API 623, ISO 15761, GB/T 12235, and EN 13789. Always verify model-specific values and standards with the legal manufacturer or supplier before selection or installation.

The valve operates by moving a disc (or plug) perpendicular to the seat, creating a variable annular opening. When the stem is turned, the disc moves linearly, changing the flow area. This design allows for precise throttling and positive shut-off when the disc fully contacts the seat. The linear motion of the disc relative to the seat provides a predictable flow characteristic, making it suitable for regulating flow in systems where frequent adjustment is needed. The pressure drop across the valve is higher than that of gate valves due to the change in flow direction, but this is acceptable in applications where throttling is prioritized.