Specification

Bellows Seal Flanged High Pressure Cast Steel Globe Valve

I. Product Overview

NEWWAY bellows seal flanged globe valves are engineered for toxic, flammable, and high-purity media, featuring dual sealing from bellows and packing to eliminate external leakage. Constructed from WCB cast steel, 304/316 stainless steel, and CF8/CF8M, they cover DN15-DN150 (1/2″-6″) with PN16-PN40 (1.6MPa-4.0MPa), suitable for -29℃~425℃. The valve regulates flow via stem movement, offering linear flow characteristics for precise control in chemical, pharmaceutical, and power industries with strict leakage requirements.

II. Core Technical Parameters

Specifications & Pressure-Temperature Range

Nominal Diameter: DN15/20/25/32/40/50/65/80/100/125/150 (1/2″-6″)

Pressure Class: PN16/PN25/PN40 (1.6MPa/2.5MPa/4.0MPa)

Temperature Range: -29℃~200℃ (NBR bellows), -40℃~425℃ (stainless steel bellows)

Materials & Sealing System

Body Bonnet: WCB cast steel (A216 WCB), 304/316 stainless steel (A351 CF8/CF8M)

Bellows: 316L stainless steel (wall thickness 0.25-0.5mm), 2-4 layers, fatigue life ≥10,000 cycles

Seat Seal: PTFE (standard), PPS (high-temp), hard alloy (abrasion-resistant)

Connection: Flanged (ASME B16.5, GB/T 9113), RF/FF face

Actuation & Operation

Actuation: Manual (with gearbox option), electric (IQ series actuator), pneumatic (double-acting cylinder)

Flow Characteristic: Linear, turndown ratio 100:1

Protection Grade: IP67 (electric actuator), Ex d IIB T4 (explosion-proof option)

Product Overview

III. Structural Design & Technical Features

Dual Sealing Assurance

Bellows welded between stem and bonnet form a metal diaphragm seal, external leakage ≤1×10⁻⁹mbar·L/s.

Packing uses V-type PTFE+graphite as a secondary seal against bellows failure.

Hydrodynamic Optimization

Streamlined flow path reduces pressure drop by 15% vs. traditional globe valves (DN50 Cv=15).

Plunger-type disc design eliminates friction during closure, extending seal life.

Bellows Reliability Design

Multi-layer bellows disperse stress, enhancing fatigue resistance by 300%.

Internal guide sleeve prevents stem offset, ensuring coaxial bellows movement.

IV. Manufacturing Processes & Quality Control

Bellows Fabrication

Hydraulic forming with wall thickness tolerance ≤±0.03mm, corrugation height error ≤±0.1mm.

TIG automatic welding with 100% helium mass spectrometry leak test, leakage ≤1×10⁻⁹Pa·m³/s.

Body Machining Precision

Seat sealing surface CNC lapped to flatness ≤0.005mm, roughness Ra≤0.4μm.

Stem straightness ≤0.01mm/m, coaxiality with bellows ≤0.05mm.

3D Quality Inspection

Hydrostatic test: 1.5x working pressure for shell (30min hold), 1.1x for sealing (zero leakage).

Bellows fatigue test: 10,000 cycles without failure (ASME BPVC Section VIII Div.1).

Material spectral analysis: Element deviation ≤0.03% per heat.