API · ASME · DIN · EN standard industrial valves
Bellow Seal Gate Valves
Bellow seal gate valves replace the stem packing as the primary seal with a welded metal bellow between bonnet and stem; the bellow stretches and compresses with stem travel, so no stem movement can open a leak path. The bellows and packing form a dual sealing structure, and assemblies are helium leak-tested for zero leakage, which is why the construction serves fugitive-emission duty on toxic, flammable or vacuum service. The benchmark cast range covers NPS 2" to 30" (DN50 to DN1650) and ASME Class 150 to 1500 (PN16 to PN260), in carbon steel, stainless, alloy, low-temperature, duplex and nickel-base bodies with RF, butt-weld or RTJ ends and manual, pneumatic, electric or hydraulic operation; forged small-bore segments run NPS 3/8 to 2 at Class 150 to 2500. Bellows stacks are hydroformed with a minimum of two plies in 316Ti, nickel-molybdenum alloy, nickel-chromium alloy or nickel-copper alloy, carried on non-rotating stems with a backseat and API 624 packing as secondary seals. Duty limits matter as much as ratings: full-open/full-close only (no throttling), a finite cycle life, slow handwheel operation, and clean media to keep the bellow cavity free of wear particles.
Part of the Gate Valves family
Last updated: 2026-11
Family specifications
| size range | NPS 2" to 30" |
|---|---|
| pressure class | ASME Class 150 to 1500 (PN16 to PN260) |
| body materials | Carbon Steel, Low Temperature Carbon Steel, Martensitic Stainless Steel, Low Alloy Steel, Austenitic Stainless Steel, Duplex, Super Duplex, Nickel Alloy Steel |
| end connections | SW – ASME B16.11, NPT – ASME B1.20.1, BW – ASME B16.25, FLANGED – ASME B16.5, FLANGED – BS EN 1092, COMPACT FLANGE – NORSOK L-005, HUB – According to Customer Request |
| operation | Manual, Pneumatic, Electric, Hydraulic |
| design standards | Design per API 602, ASME B16.34 and MSS SP-117, inspection and testing per API 598 and MSS SP-117, fugitive-emission compliance per API 624, ISO 15848 and TA Luft. |
| design standards | ASME B16.34, ASME B31.3, ISO 15761, API 602, API 600, MSS SP-117 |
| bellows leak test | Every bellow assembly is helium leak-tested to assure zero leakage; each valve is tested per API 598. |
| secondary stem seals | Stem backseat plus API 624 stem packing act as secondary stem seals behind the bellow. |
| stem design | Non-rotating stems prevent torsion of the bellow during stroke. |
| bellows materials | 316Ti, nickel-molybdenum alloy, nickel-chromium alloy, nickel-copper alloy |
| bellows construction | Bellows are hydroformed with a minimum of two layers (plies). |
| packing standard | High-quality packing per API 622 for low-emission performance compliant with API 624; seal-welded bellows isolate the packing from process media. |
| small bore segment | Forged small-bore bellow-sealed segment: NPS 3/8 to 2 (DN10-DN50), ASME Class 150 to 2500. |
| dual seal redundancy | Bellows and packing form a dual sealing structure: the bellows is the primary stem seal and the packing backs it up, so a bellows failure does not become an immediate leak path. |
| gate duty limit | Bellow-seal gate valves are for full opening and closing only; adjustment and throttling are not permitted. |
| bellows maintenance | Bellows are critical components and require regular inspection for leaks, damage, or deterioration; replace promptly when found. |
| duty environment | Particularly suitable for harsh service involving toxic, flammable or explosive media, or high temperature and pressure conditions. |
| cycle life limit | Avoid exceeding the designed number of opening and closing cycles to prolong the bellows lifespan. |
| operation care | Operate the handwheel or actuator slowly to avoid damaging the bellows through excessive force or speed. |
| medium cleanliness | Ensure pipeline cleanliness so impurities do not enter the valve cavity and affect sealing performance. |
| bellows rupture response | On bellows rupture: cease operation immediately and close the upstream and downstream isolation valves to prevent media leakage. |
| forged series osy design | features an outside stem and yoke (OS&Y), bolted / welded bonnet and conventional port with either threaded, socketweld or RF ends |
| forged series design standards | manufactured in accordance with API 602 and ASME B16.34 standards |
| forged series size range | Sizes 1/2” – 2” |
| forged series pressure class | Pressure Class 150, 300, 600, 800 |
| forged series compliance program | API 598/602/624, ASME B16.34, NACE MR-0175, NACE MR-0103 |
| forged series end connection options | Threaded, Socketweld, Flanged, Buttweld |
| forged series bonnet options | Bolted, Welded |
| forged series style codes b800 | B800, B870, B815, B830, B860 |
| forged series style codes bg | BG80, BG87, BG81, BG83, BG86 |
| forged series materials breadth | Large scope of materials and trims available |
| forged series safety critical duty | suitable for extreme, safety-critical environments like nuclear power generation and petrochemical manufacturing |
| din3352 series design standard | DIN 3352 |
| din3352 series body materials | ASTM A216 WCB, A351 CF3, CF8, CF8M, CF3M |
| din3352 series wedge material | ASTM A182 F316Ti |
| din3352 series size range | 1/2-24 Inch, DN15-DN600 |
| din3352 series pressure class | Class 150-600 LB (PN16, PN25, PN40, PN64, PN100) |
| din3352 series end connections | RF, RTJ, FF |
| din3352 series flange standard | DIN 2543-2545 |
| din3352 series face to face standard | DIN 3202 |
| din3352 series testing standard | DIN 3230 |
| din3352 series temperature range | -29°C to 550°C |
| din3352 series certifications | TA-Luft, ISO 15848-1, API 622 |
| din exec design standards | DIN 3356, BS 5160, ASME B16.34 |
| din exec end to end standards | ASME B16.10, EN558-1 / DIN 3202 |
| din exec flange end standards | ASME B16.5, ASME B16.11, ASME B1.20.1, DIN 2543~2545, EN 12627 |
| din exec testing standards | ISO 5208, DIN 3230, MSS SP-117 |
| din exec size range | DN15 through DN400 |
| din exec pressure class | ANSI CL150, CL300, CL600, CL800, CL900, PN16, PN25, PN40, PN64 |
| din exec temperature range | -20C to 350C Degree |
| din exec seat hardfacing | Hard-facing with Cr. Alloy |
| cast series materials | Carbon Steel, Stainless Steel, Alloy Steel |
| cast series size range | NPS 1/2"~ 24", DN 15~600 |
| cast series pressure class | Class 150~2500, PN 10~420 |
| cast series temperature range | -46°C~+538°C |
| cast series design standards | API 600, API 6D, ASME B16.34, GB/T 12234, GB/T 28776, JB/T 7746 |
| cast series face to face standards | ASME B16.10, GB/T 12221, EN 558 |
| cast series flange standards | ASME B16.5, ASME B16.47, GB/T 9113, JB/T 79, HG/T 20592, EN 1092, GOST 33259 |
| cast series testing standards | API 598, API 6D, GB/T 13927, JB/T 9092, GOST 9544 |
| size range asme | ASME Class 150 Lbs to 1500 Lbs – 1/4″ to 6″ |
| size range pn | BS EN 1092 Class PN 2.5 bar to PN 250 bar – 3/8″ to 6″ |
| end to end standard | ASME B16.10 Short and Long Pattern, BS EN 558 |
| bonnet connection | Bolted Bonnet, Welded Bonnet |
| seat type | Renewable Press Fit or Threaded |
| obturator type | Solid Wedge, Flexible Wedge, Split Wedge |
| stem packing | Bellow Seal + Graphite, PTFE |
| operator type | Manual : Handwheel or Gearbox, Actuated: Electric, Pneumatic, Hydraulic |
| testing | Hydrostatic, High Pressure Gas, Pneumatic and Functional, ISO 5208 – API 598 – API 6A – API 6D, Cryogenic and Low Temperature Test: BS 6364 – ISO 28921, Fugitive Emission Test: ISO 15848, Fire Safe: ISO 10497 |
| stem type | Outside Screw & Yoke, Rising Stem, Rotating Stem, Non Rotating Stem, Anti Blow Out |
| back seat type | Integral |
| seat seal | Metal, Soft |
| body bonnet gasket | Metal: Spiral Wound, Ring Joint |
| additional features | Locking Device, Position Indicator, Stem Protection, Packing Complete with Lantern Ring and Grease Injector, Packing Vacuum Service, Loaded Spring Packing, Extended Bonnet, Collar Drip Plate, Insulation, Extended Stem, Quill, Nipples, Gusset, Jacket and Semi Jacket, Bare Stem complete with actuator flange, Operator Antitamper, Equalizing hole in Gate |
| vent drain | Plugged, Flanged, With Valve, Any type of connection upon request |
| certifications | PED 2014/68/EU Mod. H, ATEX 2014/34/EU |
| end to end class800 bolted or welded | NPS 1/2: 76 mm | NPS 3/4: 86 mm | NPS 1: 102 mm | NPS 1-1/4: 118 mm | NPS 1-1/2: 118 mm | NPS 2: 132 mm (end-to-end length, Class 800 bolted or welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| bore diameter class800 bolted or welded | NPS 1/2: 9.5 mm | NPS 3/4: 12.7 mm | NPS 1: 17.5 mm | NPS 1-1/4: 23.8 mm | NPS 1-1/2: 28.6 mm | NPS 2: 36.5 mm (bore diameter, Class 800 bolted or welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| center to top open class800 bolted or welded bolted | NPS 1/2: 329.2 mm | NPS 3/4: 353.7 mm | NPS 1: 425.5 mm | NPS 1-1/4: 577.4 mm | NPS 1-1/2: 577.4 mm | NPS 2: 712.1 mm (center-to-top (open) height, bolted bonnet, Class 800 bolted or welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| center to top open class800 bolted or welded welded | NPS 1/2: 289.2 mm | NPS 3/4: 319.8 mm | NPS 1: 372.7 mm | NPS 1-1/4: 533.3 mm | NPS 1-1/2: 533.3 mm | NPS 2: 700 mm (center-to-top (open) height, welded bonnet, Class 800 bolted or welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| handwheel class800 bolted or welded | NPS 1/2: 90 mm | NPS 3/4: 90 mm | NPS 1: 110 mm | NPS 1-1/4: 150 mm | NPS 1-1/2: 150 mm | NPS 2: 150 mm (handwheel diameter (W), Class 800 bolted or welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| weight class800 bolted or welded | NPS 1/2: 3.5 kg | NPS 3/4: 4.0 kg | NPS 1: 5.5 kg | NPS 1-1/4: 8.5 kg | NPS 1-1/2: 8.5 kg | NPS 2: 16 kg (approx weight, Class 800 bolted or welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| end to end class900 1500 welded | NPS 1/2: 90 mm | NPS 3/4: 104 mm | NPS 1: 120 mm | NPS 1-1/4: 130 mm | NPS 1-1/2: 130 mm | NPS 2: 150 mm (end-to-end length, Class 900/1500 welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| bore diameter class900 1500 welded | NPS 1/2: 9.5 mm | NPS 3/4: 12.7 mm | NPS 1: 16 mm | NPS 1-1/4: 22.5 mm | NPS 1-1/2: 27 mm | NPS 2: 35 mm (bore diameter, Class 900/1500 welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| center to top open class900 1500 welded | NPS 1/2: 300 mm | NPS 3/4: 320 mm | NPS 1: 380 mm | NPS 1-1/4: 530 mm | NPS 1-1/2: 530 mm | NPS 2: 580 mm (center-to-top (open) height, Class 900/1500 welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| handwheel class900 1500 welded | NPS 1/2: 90 mm | NPS 3/4: 110 mm | NPS 1: 150 mm | NPS 1-1/4: 150 mm | NPS 1-1/2: 150 mm | NPS 2: 180 mm (handwheel diameter (W), Class 900/1500 welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| weight class900 1500 welded | NPS 1/2: 5 kg | NPS 3/4: 7.5 kg | NPS 1: 11.5 kg | NPS 1-1/4: 19 kg | NPS 1-1/2: 19 kg | NPS 2: 30 kg (approx weight, Class 900/1500 welded bonnet, regular port size, full port one size smaller, threaded and socket weld ends, ASME B16.34/API 602) |
| end to end class150 flanged | NPS 1/2: 108 mm | NPS 3/4: 117 mm | NPS 1: 127 mm | NPS 1-1/2: 165 mm | NPS 2: 178 mm (end-to-end length, Class 150 Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| end to end class300 flanged | NPS 1/2: 140 mm | NPS 3/4: 152 mm | NPS 1: 165 mm | NPS 1-1/2: 190 mm | NPS 2: 216 mm (end-to-end length, Class 300 Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| end to end class600 flanged | NPS 1/2: 165 mm | NPS 3/4: 190 mm | NPS 1: 216 mm | NPS 1-1/2: 241 mm | NPS 2: 292 mm (end-to-end length, Class 600 Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| bore diameter class150 300 600 flanged | NPS 1/2: 9.5 mm | NPS 3/4: 12.7 mm | NPS 1: 17.5 mm | NPS 1-1/2: 28.6 mm | NPS 2: 36.5 mm (bore diameter, Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| center to top open class150 300 600 flanged | NPS 1/2: 145.5 mm | NPS 3/4: 151.8 mm | NPS 1: 179.7 mm | NPS 1-1/2: 247 mm | NPS 2: 268.7 mm (center-to-top (open) height, Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| handwheel class150 300 600 flanged | NPS 1/2: 90 mm | NPS 3/4: 90 mm | NPS 1: 110 mm | NPS 1-1/2: 150 mm | NPS 2: 150 mm (handwheel diameter (W), Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| weight class150 flanged | NPS 1/2: 3 kg | NPS 3/4: 3.8 kg | NPS 1: 4.8 kg | NPS 1-1/2: 10 kg | NPS 2: 15 kg (approx weight, Class 150 Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| weight class300 flanged | NPS 1/2: 3.4 kg | NPS 3/4: 4.5 kg | NPS 1: 5.7 kg | NPS 1-1/2: 11.5 kg | NPS 2: 17 kg (approx weight, Class 300 Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
| weight class600 flanged | NPS 1/2: 4 kg | NPS 3/4: 5.2 kg | NPS 1: 6.6 kg | NPS 1-1/2: 12.7 kg | NPS 2: 18 kg (approx weight, Class 600 Class 150-300-600 overall-end flange, bolted bonnet, regular port, structure length ASME B16.10, flange ASME B16.5) |
Ordering & documentation
Documents
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Quotation
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Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of bellow seal gate valves?
The published specification for this family lists Design per API 602, ASME B16.34 and MSS SP-117, inspection and testing per API 598 and MSS SP-117, fugitive-emission compliance per API 624, ISO 15848 and TA Luft. as the design standards.
What sizes and pressure ratings are available for bellow seal gate valves?
The published size range is NPS 2" to 30", and the published pressure ratings are ASME Class 150 to 1500 (PN16 to PN260). Availability of a specific size and rating is confirmed at quotation.
What materials are bellow seal gate valves available in?
The published specification lists body materials: Carbon Steel, Low Temperature Carbon Steel, Martensitic Stainless Steel, Low Alloy Steel, Austenitic Stainless Steel, Duplex, Super Duplex, Nickel Alloy Steel. Material availability for a specific size and rating is confirmed at quotation.
What end connections do bellow seal gate valves support?
The published specification lists SW – ASME B16.11, NPT – ASME B1.20.1, BW – ASME B16.25, FLANGED – ASME B16.5, FLANGED – BS EN 1092, COMPACT FLANGE – NORSOK L-005, HUB – According to Customer Request as the available end connections. The connection for a specific size is confirmed at quotation.
What should a quotation inquiry for bellow seal gate valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
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