Globe Valves

Globe valves are designed for throttling, flow regulation, and frequent operation: the disc closes against a horizontal seat ring, giving a linear flow characteristic with stem travel. The Z-shaped flow path creates a predictable, controllable pressure drop. Gate valves are for on-off isolation only - they must not be throttled. Use globe valves wherever the valve will be partially open for sustained periods, where frequent cycling is expected, or where precise flow rate adjustment is required.

The Z-type (standard pattern) has inlet and outlet on the same axis - the most common design for general service. The Y-type (angle pattern) has the seat at approximately 45° to the flow axis - lower pressure drop and better suited for high-pressure blow-down, drain valves, or where fouling of the cavity is a concern. The angle globe valve has inlet and outlet at 90° to each other - ideal for applications where the piping already changes direction, eliminating one elbow and reducing pressure drop and space.

Three methods: (1) Low-emission (LE) packing - multi-ring graphite or PTFE braided packing systems with live-loaded packing glands (belleville springs) that maintain sealing force as packing wears; tested to ISO 15848-1 Class B or C. (2) Bellows sealed design - metallic 316L stainless bellows welded to stem and bonnet, with packing as a secondary seal; achieves ISO 15848-1 Class A (< 10 ppm). (3) Specification to TA-Luft VDI 2440 (Germany) or EPA Method 21 for facilities with regulatory fugitive emission limits.

For steam service above 250°C: Carbon Steel WCB (rated to 425°C). Above 425°C: Alloy Steel WC6 (1.25Cr-0.5Mo, to 510°C) or WC9 (2.25Cr-1Mo, to 565°C). Above 565°C: C12A/P91 (9Cr-1Mo-V, to 620°C). All high-temperature globe valves require Stellite hard-facing on disc and seat for wear resistance, and graphite packing for temperature stability. Full PMI and PWHT documentation is provided.