Globe Valve Bellow Seal - Cast Steel | Neway

Neway Cast Steel Bellow Seal Globe Valve

The Neway cast steel bellow seal globe valve is designed for line isolation where stem leakage must be minimized beyond conventional packing. It is applicable in steam, hot water, condensate, process gases, thermal circuits, refineries, chemical plants, and power generation.

Construction Range

The available range covers NPS 2"–30", pressure rating ASME Class 150–1500 / PN16–PN260, with end connections RF, BW, or RTJ. Body materials include carbon steel, stainless steel, alloy steel, low-temperature steel, duplex stainless steel, and nickel-base alloys.

Design and Standards

The basic construction of cast steel globe valves follows API 623 design, bolted bonnet, OS&Y, rising stem & handwheel, screwed-in back seat, and swivel disc. Connections and testing adhere to ASME B16.10, ASME B16.5 / B16.47, ASME B16.25, and testing per API 598 or EN 12266.

Stem Sealing

The bellows sealed version is used when low atmospheric leakage is required, e.g., in high-temperature steam, toxic/odorous fluids, or networks with high medium loss costs. The bellows act as the primary barrier on the stem, while packing remains a secondary seal and maintenance checkpoint. The technical leaflet shows a specific arrangement for casting steel bellows sealed valves and the option for double sealing gasket/packing with intermediate leakage detection.

Application Selection

Selection should consider:

• ASME Class and pressure-temperature rating.
• Compatibility of body, trim, bellows, and packing with the fluid.
• Differential pressure across the disc and required operating torque.
• RF, RTJ, or BW connection per piping specification.
• Manual, pneumatic, electric, or hydraulic actuation requirements.

FAQ

When to choose bellows seal over conventional globe valve?
When stem leakage is unacceptable due to emissions, safety, steam loss, or maintenance costs.

Is it suitable for throttling?
The globe geometry allows limited regulation, but ΔP, velocity, cavitation/flashing, and seat wear must be checked.

What is needed before ordering?
NPS, Class, body material, trim, end type, medium, temperature, operating pressure, ΔP, and actuator requirement.