NPS 1/2″ Class 600 BW ASME Standard Bellows Sealed Globe Valve – CF8M
NPS 1/2″ Class 600 Butt Weld (BW) Bellows Sealed Globe Valve (CF8M Body). Manufactured to ASME B16.34 and BS 1873 / API 602 and ASME B16.25 with multi-ply hydroformed Inconel 625 / Hastelloy C276 bellows (>10,000 cycle endurance). Features dual-barrier stem sealing (hermetic metallic bellows primary + live-loaded flexible graphite secondary packing), integral backseat, and Stellite hardfaced conical plug disc for zero-leakage isolation in thermal oil, steam, and hazardous chemical pipelines.
Description
The NPS 1/2″ Class 600 Butt Weld (BW) ASME Standard Bellows Sealed Globe Valve (CF8M) is an engineered high-integrity, zero-leakage linear flow control valve manufactured by XIAMEN GUTE VALVE MANUFACTURING COMPANY. Designed in rigorous compliance with ASME B16.34 and BS 1873 / API 602 and international emission containment standards, it is specifically built for severe industrial applications including high-temperature thermal oil (Heat Transfer Fluids), supercritical steam, toxic gases, and volatile organic chemicals. Featuring a multi-ply hermetically sealed Inconel 625 / Hastelloy C276 metallic bellows capsule backed by a secondary live-loaded flexible graphite packing gland, an integral precision backseat, and Stellite hardfaced seating, it completely eliminates fugitive stem emissions and guarantees bubble-tight shutoff across demanding chemical, petrochemical, and power generation networks.
Engineering Configuration & Dimensional Specifications
NPS 1/2″ | Class 600 | Bellows Sealed Globe Valve | CF8M | Butt Weld (BW)
- Face-to-Face Length (L): 165 mm (ASME B16.34 and BS 1873 / API 602)
- Bare Valve Net Weight: 5.8 kg
- Primary Stem Sealing: Multi-ply Hydroformed Inconel 625 / Hastelloy C276 Hermetically Welded Bellows (>10,000 Cycle Life)
- Secondary Emergency Sealing: Independent Live-Loaded Flexible Graphite Packing Gland + Integral Backseat
- Fugitive Emission Tightness: Certified Compliant with ISO 15848-1 Class AH and German TA-Luft (< 100 ppmv)
- Seat Tightness Standard: API 598 Rate A (Zero Bubble Leakage)
Rigorous Quality Assurance & Inspection Protocols
Every bellows sealed globe valve undergoes 100% multi-stage factory quality verification and non-destructive testing per API 598 standards to guarantee zero leakage and pressure boundary containment:
- 1. Material Chemistry Analysis (PMI): 100% Spectro chemical verification on all pressure-retaining casting and forging heats with certified EN 10204 3.1 Mill Test Reports (MTR).
- 2. Bellows Helium Mass-Spectrometry Leak Testing: 100% high-vacuum helium mass-spectrometer testing on welded bellows sub-assemblies before final valve assembly, verifying helium leakage rates < 1×10^-6 mbar·l/s.
- 3. Precision Dimensional Checks: 100% tolerance validation of face-to-face, stem stroke, and flange drilling against ASME B16.34 and BS 1873 / API 602 drawings.
- 4. Hydrostatic & Fugitive Emission Testing: 100% shell hydrostatic testing at 1.5x rating, high/low pressure seat closure tests, and helium fugitive emission validation per ISO 15848-1.
Frequently Asked Technical Questions
A: Conventional gland-packed valves rely on mechanical friction packing rings that inevitably degrade, relax, and weep during thermal cycles and frequent stroking, creating dangerous fugitive emissions. In this Gute NPS 1/2″ valve, a multi-ply hydroformed metal bellows forms a hermetically sealed, flexible metal barrier welded between the stem and body/bonnet. It completely isolates moving stem packing from line fluid, eliminating stem leakage (certified compliant with TA-Luft and ISO 15848-1 Class AH < 100 ppmv) and protecting operating personnel against hazardous, flammable, or expensive media losses.
A: Gute Bellows Sealed Globe Valves incorporate a redundant dual-containment design. Above the primary multi-ply bellows capsule, the valve features an independent secondary stuffing box equipped with die-formed high-density flexible graphite packing rings live-loaded with Belleville spring washers. Additionally, the stem includes an integral precision-machined backseat. If the bellows ever experiences fatigue after extended millions of cycles, the secondary gland packing and backseat completely contain line pressure, preventing catastrophic atmospheric escape.
A: In small-bore NPS 1/2″ lines with high pressure drops, fluid velocity across the seat can accelerate dramatically upon crack-opening. Gute conical plug discs and body seat rings feature Plasma Transferred Arc (PTA) Stellite No. 6 cobalt-base hardfacing (hardness 38–42 HRC). The narrow conical profile provides linear flow throttling, breaks through particulate scale, and eliminates wire-drawing erosion, ensuring bubble-tight shutoff conforming to API 598 Rate A zero leakage.
Need Technical Assistance or Custom Sizing?
Our engineering team can assist with bellows material selection, high-temperature sizing calculations, and RFQ support.
Additional information
| Material | |
|---|---|
| Pressure | |
| Valve Size | |
| Connection | |
| Design Standard | ASME Standard |
| Size | NPS 1/2" |
| Pressure Class | Class 600 |
| Body Material | CF8M |
| End Connection | BW |
| Operation | Handwheel |
| Design Structure | Bolted Bonnet (BB) + Bellows Seal |
| Manufacturer | XIAMEN GUTE VALVE MANUFACTURING COMPANY |
| Trim / Internals | Inconel 625 Bellows + Stellite Trim |
