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KSB Bellow Seal Gate Valve BSGT-S Carbon Steel — Zero Emission

ECOLINE BSGT-S with AISI 316 Ti metal bellows as primary stem seal. Double seal design: bellows + backup gland packing. A216 WCB (cast) and A105 (forged) body. Class 150/300 (cast) and Class 800 (forged). NPS ½–8. Zero fugitive emission for hazardous, toxic, and vacuum service.

Carbon Steel WCB/A105Class 150, 300, 800NPS ½–8 (cast); NPS ½–2 (forged)

Specifications

ParameterSpecification
SeriesECOLINE BSGT-S
Body MaterialA216 WCB (cast) / A105 (forged)
Pressure ClassClass 150, 300, 800
Size RangeNPS ½–8 (cast); NPS ½–2 (forged)
Max Temperature400°C
Max PressureClass 300: 51 bar; Class 800: 136 bar
Design StandardANSI/ASME
End ConnectionsFlanged RF (cast), Socket Weld (forged)
ConstructionExtension cylinder with AISI 316 Ti welded metal bellows, backup graphite gland packing
Trim / SealingIntegral seat with Stellite hard-facing option
✓ ANSI/ASME

Material & Applications

Why Carbon Steel WCB/A105: The AISI 316 Ti metal bellows provides a hermetic primary stem seal — zero leakage to atmosphere under any operating condition. The bellows expands and contracts with stem movement (valve open/close cycles) without any rubbing contact that would cause wear. The backup gland packing provides a secondary seal if the bellows is ever damaged, giving operators time to plan a safe shutdown for maintenance rather than facing an immediate emission event. This double-seal design meets the strictest fugitive emission standards including ISO 15848 and TA-Luft.

Typical applications: Chemical plants handling toxic, carcinogenic, or hazardous fluids. Vacuum service where air ingress through conventional packing would break the vacuum. LPG/LNG service. Pharmaceutical clean rooms. Any application subject to EPA, CPCB, or ISO 15848 fugitive emission regulations. Also used for expensive or irreplaceable process fluids where even minor stem leakage is unacceptable.

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Other Variants

Bellow Seal Globe CS BSGL-S Bellow Seal Stainless Steel CF8M All Bellow Seal Valves →

Service Area

Pune, Ahmednagar & Beed.

Carbon Steel WCB/A105 Bellow Seal Valve FAQs

What is a bellow seal valve?
A valve where the stem is sealed by a welded metal bellows instead of conventional packing. The bellows is a thin-walled corrugated tube welded to the stem and bonnet, creating a hermetic barrier between the process fluid and the atmosphere. As the stem moves, the bellows flexes rather than sliding against a packing surface, eliminating the wear and leakage inherent in packed valves.
When is bellow seal required?
Required by regulation or best practice for: (1) toxic fluids — chlorine, ammonia, hydrogen sulphide, benzene, ethylene oxide, (2) carcinogenic fluids — vinyl chloride, butadiene, (3) flammable fluids in confined spaces — LPG, LNG, hydrogen, (4) vacuum service where air ingress through packing breaks the vacuum, (5) expensive process fluids where stem leakage represents direct financial loss, (6) plants subject to EPA Method 21, CPCB emission norms, or ISO 15848 requirements.
How many cycles can the bellows handle?
KSB 316 Ti bellows are designed for a minimum of 10,000 full-stroke cycles. Actual life depends on operating conditions, temperature cycling, and the aggressiveness of the fluid. Regular inspection during shutdowns is recommended.
Gate vs globe bellow seal?
Gate (BSGT-S): full-bore isolation with low pressure drop, on-off service only. Globe (BSGL-S): throttling and flow regulation capability, higher pressure drop. Choose gate when you only need to open or close the valve. Choose globe when you need to control flow rate.

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