Control Valve bellow seal Single-seated | Neway

Neway CBS – Single-Seated Control Valve with Bellows

The Neway CBS is a globe-type control valve featuring a single-seated plug and a metal bellows to minimize external leakage from the stem. It is designed for straight-travel control of flow, pressure, level, or temperature in applications where packing is insufficient as the primary sealing barrier.

Construction Range

The series covers 3/4"–8" / DN15–DN200, with a pressure rating of ASME Class 150–1500 / PN16–PN250. Bodies are available in carbon steel, stainless steel, alloy steel, and duplex stainless steel. Trim materials include stainless, alloy steel, and duplex, while the bellows are available in 304, 316, 316Ti, or Inconel depending on temperature, media, and operational cycles.

Trim, Control, and Leakage

The single-seat trim is suitable for low seat leakage and stable regulation in clean or moderately loaded processes. Available characteristics include equal percentage, linear, and quick open, with a rangeability of 50:1. Seat leakage is defined per FCI 70-2, in Class IV, V, or VI with a soft seat.

Connections and Temperature

Connections include FF, RF, RTJ, LF, and BW. Face-to-face dimensions are provided per ISA S75.03 for Class 150–600 and ISA S75.16 for Class 900–1500. The temperature range of the series is from -196°C to +538°C, with standard, extension, or low-temperature bonnet options.

Actuation

The valve is compatible with pneumatic actuators PDL/PCL or electric actuators AUMA / ROTORK. Actuator selection should consider Δp at closure, required thrust, fail-open/fail-close position, and available instrument air.

FAQ

When to choose a bellows?
For toxic, volatile, corrosive, or thermal fluids where shaft leakage must be minimized.

Selection Criteria: media, Cv/Kv, P1/P2, temperature, leakage class, bellows material, bonnet type, connection, and fail-safe position.