Control Valve bellow-seal | Bellino

Bellino Bellow Seal – Analog Globe Valve

The Bellino Bellow Seal is a globe-type control valve designed for applications where shaft sealing leakage must not rely solely on packing. The metallic bellows isolate the shaft from the medium, suitable for flow, pressure, level, or temperature control loops in liquids and gases.

Trim and Materials

The bellow seal version is available with the same basic trims as Bellino control valves, such as GVPC, GVCH, and GVLN. This allows selection of contoured trim, cage trim, or low-noise trim based on Δp, noise, cavitation/flashing, and required Cv. Standard bellows materials include SS316/SS316L, Inconel 625, Monel 400, and Hastelloy C-276.

Pressure, Connection, and Standards

The catalog features versions with RF/RJ flanged connections and dimensions according to ANSI/ISA 75.08.01, with tables for ANSI 150, ANSI 300, and ANSI 600. Other sizes are available upon technical selection. General valve design references include ASME B16.34, API 6A, API 600, and ASME BPVC, where applicable.

Sealing and Maintenance

The bellows reduce the likelihood of external shaft leakage, but selection must consider operating cycles, temperature, pressure, and chemical compatibility. Secondary packing or leakage monitoring is recommended when the medium is toxic, volatile, or corrosive.

Seat leakage is specified separately according to ANSI/FCI 70-2. Bellino specifies classes IV, V, and VI; Class IV/V with metal-to-metal seat and Class VI with resilient seat.

Typical Applications

• Steam and condensate
• Thermal oils
• Chemical and corrosive fluids
• Volatile or odorous media
• Gas service with fugitive emissions control

FAQ

When to choose bellow seal over simple packing?
When external shaft leakage is a critical safety, environmental, or maintenance factor.

What is required for selection?
Medium, Cv, P1/P2, temperature, leakage class, bellow material, trim type, fail position, and available instrument air pressure.