Manual Bellow Seal Globe Valve

Manual bellows-sealed globe valves are industrial control valves that combine a bellows sealing structure with manual operation. Designed for applications requiring zero leakage and contamination prevention, these valves use a bellows assembly to completely isolate the stem from the valve body, while a handwheel provides precise manual control. They offer the core advantages of reliable sealing, easy operation, and compact structure, and are widely used in industries such as petrochemical, pharmaceutical, food processing, and metallurgy for accurate on/off control and flow regulation.

The structural design focuses on sealing performance and operational convenience. The valve body is made from materials such as WCB cast steel, 304/316L stainless steel, or Hastelloy to suit various corrosive media, and is manufactured through precision casting or forging. The flow path adopts a straight-through or angled design with low flow resistance for smooth medium passage. The stem and bellows are integrated; the bellows is made from Inconel 600/625 high-temperature alloys or stainless steel and formed through multi-layer rolling, providing excellent pressure resistance and fatigue durability. This design completely prevents medium leakage along the stem, achieving sealing performance in accordance with ANSI B16.104 Class VI.

The valve plug is solid-forged stainless steel, with sealing surfaces overlay welded with Stellite or hardfacing alloys (hardness ≥ HRC 55) to form a precise sealing pair with the valve seat. The stem is quenched, tempered, and nitrided, and paired with rolling bearings to reduce operating torque. The handwheel features an anti-slip design, offering comfortable manual operation and precise control of the valve opening.

Key technical parameters include nominal sizes from DN15 to DN200 (1/2"–8"), pressure ratings from PN10 to PN420 (Class 150–2500 LB), and an operating temperature range of –196 °C to 450 °C. High-temperature models use high-temperature alloy bellows capable of withstanding extreme temperatures up to 550 °C. Connection types include flanged (in accordance with ASME B16.5 and GB/T 9113), threaded, and butt-welded ends, making the valve compatible with various piping systems. Manufacturing and testing strictly follow ASME B16.34, API 598, and GB/T 12224 standards, including shell pressure tests, sealing tests, and bellows fatigue testing.

In terms of performance, the valve offers three major advantages. First, it provides zero-leak sealing: the dual sealing of the bellows and packing completely prevents stem leakage, ensuring environmental safety and contamination-free operation. Second, it is easy to operate: manual actuation with low torque allows smooth operation even for small- to medium-sized valves, and the opening can be precisely adjusted. Third, it is highly durable: the bellows assembly resists aging and corrosion, and the valve plug sealing surfaces are wear-resistant, providing a service life two to three times longer than conventional globe valves. These valves are suitable for oil, chemical media, steam, and high-temperature gases, and are typically applied in chemical reactors, pharmaceutical process pipelines, food processing equipment, and high-temperature metallurgical piping.