API · ASME · DIN · EN standard industrial valves
Jacketed Butterfly Valves
Jacketed butterfly valves keep media that solidifies, crystallises or thickens at ambient temperature in a flowable state: the body carries a full heating jacket through which steam, thermal oil or hot water circulates, so bitumen, sulphur, chocolate, waxes and adhesives stay liquid right up to the disc. Size range, class coverage, body materials and end connections are confirmed per size and execution at RFQ; the jacket medium and temperature are selected against the process conditions. Jacket construction is graded by coverage: partial jackets heat the body mid-section through standard flanges, full-coverage jackets use connecting flanges one to two nominal sizes above line size, and line-size jackets weld to standard flanges - so face-to-face is quoted as ISO 5752 "or approved manufacturer drawing", and thermal ports step from 1/2-inch NPT on small valves to 1-inch on 8-inch-and-larger bodies. Metal seats with hard-faced sealing surfaces carry the hot end of a -29 to 425 °C material-dependent envelope. The failure paths are thermal rather than mechanical: clamp-on jackets leave air-gap cold spots where media solidifies, product building on the disc edge blocks opening or closing, and solidified media at the shaft bearing binds the stem - steam-traced stem and sealed-bearing designs answer the last. Installation routes the jacket medium in one connection and out the opposite side with annular space sized against hot and cold spots, and acceptance is two-sided: jacket hydro per ASME B31.1, process side per API 598. Product standards are the butterfly ones (API 609, MSS SP-68, EN 593) while the jacket shell follows piping practice (ASME B31.1/B31.3, B16.34); jacketed high-performance executions run to Class 600 with pressure-temperature limits from B16.34. Selection turns on jacket heating medium and temperature, body and seat materials against the media chemistry, and actuation — manual, pneumatic or electric.
Part of the Butterfly Valves family
Last updated: 2026-10
Family specifications
| jacket coverage design types | Jacketed valve executions are commonly grouped by coverage: a partial jacket heats only the valve mid-section with standard flanges, a full-coverage jacket uses flanges one nominal size above the valve size, and a line-size full jacket welds to standard flanges with tapped bolt-hole inserts. Shorter end-to-end variants of each also exist. |
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| jacket flange oversize effect | Because the jacket adds wall thickness around the body, the connecting flanges of a jacketed butterfly valve are typically one to two nominal sizes larger than the equivalent unjacketed valve; final flange dimensions must be taken from the approved manufacturer drawing rather than assumed from the line size. |
| jacket pressure and medium separation | The jacket pressure rating, heating-medium temperature and connection size are not fixed catalog values: they must be confirmed against the process conditions for each application. The heating medium must also remain fully separated from the process medium, so jacket integrity is a containment requirement, not only a heat-transfer one. |
| jacket thermal port sizing | Thermal (steam) port size is scaled to valve size: roughly half-inch NPT on small valves, three-quarter-inch on mid sizes, and one-inch NPT on valves of about 8 inch and larger. Threaded ports are standard on fabricated jackets, with flanged jacket connections available on request. |
| jacket heating medium options | Steam is the most common jacket heating medium, but hot thermal oil is also used, and jacketed valves can serve cooling duty with cold water or chilled glycol. Manufacturer selection checklists therefore ask explicitly whether the jacket medium is steam or hot oil, together with its pressure and temperature. |
| temperature range material dependent | Published temperature limits for jacketed metal-seated butterfly valves run to about 425 C, but the applicable ceiling depends on body/trim material and the sealing configuration rather than being a single valve rating. Soft-seated executions share this envelope only in their lower part; metal seating with hard-faced surfaces carries the high end. |
| hardfaced metal seat for hot service | In jacketed executions the seat faces are typically metal, with the disc sealing surface hard-faced with a cobalt-based alloy to resist wear at elevated temperature; stainless seal rings combine hard-metal and elastic sealing behavior across the low- and high-temperature ends of the range. |
| partial jacket cold spots | Add-on (clamp-on) jackets can leave air gaps between the jacket and the valve body; these cold spots let the media solidify and accumulate locally, which is why integral welded jackets that keep steam in direct contact with the body give more reliable heating on solidifying service. |
| disc edge buildup blocks closure | A thin layer of solidified product on the disc edge can prevent the valve from opening or closing, while buildup on the disc face alters its flow-control behavior. Heating only the body does not protect the disc; designs that trace steam around the disc circumference address this failure path. |
| shaft bearing solidification binding | The shaft/bearing area is the most vulnerable point for media buildup: even a small amount of solidified flow material on a bearing surface causes binding and wear. Steam-traced or purged stem designs, and sealed bearings, are countermeasures; without them, conventional body-only jacketing leaves the shaft cold. |
| clamp on jacket valve failure risk | Reliance on conventional clamp-on jacketing is itself a failure mode: where heat transfer is poor, sulfur-type media can still solidify inside the valve and the buildup leads to valve failure, particularly where shafts and discs sit far from the heat source. |
| annular space hot cold spots prevention | For fabricated jackets, maintaining sufficient annular space between the valve exterior and the inner jacket wall keeps the thermal fluid flowing unobstructed; collapsing or under-sizing this gap produces temperature inconsistencies and hot or cold spots across the heated surface. |
| jacket flow path through both connections | The jacket is routed with an inlet on one side of the body and an outlet on the opposite side, so the heating medium circulates around the body before leaving; jacket connections are installed on both body sides, and coupling size and connection form (threaded or flanged) must be specified at ordering. |
| jacket hydrostatic test and asme compliance | Fabricated jacket welds are executed to ASME B31.1/B31.3 practice with code-qualified welders, and after fabrication the jacket space is hydrostatically tested per ASME B31.1 while the process side is tested to API 598, a two-sided acceptance sequence worth requiring in purchase specifications. |
| jacketed design and flange standards | Triple-offset metal-seated butterfly valves of the type used for jacketed executions are designed to API 609, MSS SP-68 and EN 593; connecting flanges conform to ASME B16.5/B16.47, ISO 7005 or EN 1092, face-to-face to API 609/ISO 5752/EN 558, and testing to API 598 / ISO 5208. The jacket shell additionally follows piping practice (ASME B31.1/B31.3, B16.34). |
| face to face deviation for jacketed bodies | Face-to-face dimensions nominally follow ISO 5752 (and API 609/EN 558), but jacketed bodies frequently deviate from the standard table; suppliers state conformance as ISO 5752 or approved manufacturer drawing, so buyers must verify face-to-face against the jacketed drawing rather than the standard. |
| pressure class envelope of jacketed butterfly | Steam-traced jacketed high-performance butterfly executions are offered in ASME B16.34 pressure classes including Class 150 (with a derated 150DR variant), 300 and 600, in sizes from 6 to 48 inch, confirming that the jacket does not confine the product to a single class while pressure-temperature limits are taken from B16.34. |
| jba triple point heating | triple-point prevention of media solidification in the shaft and bearings, the valve body and the disc |
| jba steam through stem | steam flows directly through the stem, fully heating the bearing area |
| jba welded shaft disc interface | There is a welded interface between the shaft inlet and disc passage forming a single, integral unit, so there is no chance for steam to leak into the piping system. |
| jba disc perimeter steam path | channels the continuous steam flow from the top shaft, around the full perimeter of the disc, and out the bottom shaft |
| jba steam contact area advantage | 200% greater steam contact area |
| jba integral jacket installation | There is no chance for assembly errors in the field and there is no need for messy thermal contact cement. |
| jba design patents | Three specific U.S.A. patents have been issued based on this design (4559967, 4418889, and 4289296). |
| jba optional configurations | Optional bearing purge (steam or alternate media) Optional sealed bearings Optional double-packed stems with lantern rings Optional fire tested and high-temperature seat designs |
| jba three point system | a full 3-point valve heating system including the stem, body, and disc |
| jbb reduced port jacketed piping | Reduced Port Valves to match reducing flanges where jacketed piping systems are required. Valves can be steam jacketed and equipped with steam traced shafts, if required. |
| jbb sulphur pitch execution | Steam Jacketed Valves with steam traced shafts for molten sulphur and pitch applications |
| jbb ordering feature codes | J = Steam jacket, T = Steam-traced shaft |
| jbb jacketed when required by application | Steam jacketed and steam traced shafts when required by application. No elastomers or teflon. |
| jbc feasibility factors | A lug-style butterfly valve can use a steam jacket, but feasibility depends on body geometry, flange-bolt access, allowable thermal distortion, steam-side design conditions, and the actual location of the deposit. |
| jbc sticking location diagnosis | Identify where sticking begins: body cavity, disc edge, stem bearing, or packing area. |
| jbc thermal survey points | Take simultaneous temperature readings on the upstream pipe, downstream pipe, body near both flanges, body centerline, upper and lower body regions, stem-bearing area, and packing area. |
| jbc metal temperature basis | Compare that target with measured metal temperature rather than steam supply temperature. Steam can be hot while a blocked condensate path or poor thermal contact leaves the valve cold. |
| jbc short face to face conduction | Short face-to-face valves can receive substantial conductive heat from the upstream and downstream piping. That heat path may already keep the main body warm, while exposed lugs, the stem extension, packing, actuator bracket, and ambient airflow create localized losses. |
| jbc deposit localization rule | If the deposit is concentrated around the stem bearing or packing, a full body jacket may consume steam without heating the controlling cold spot. If deposits cover the disc and internal body surfaces, localized stem heating will not address the obstruction. |
| jbc condensate drainage | Route steam and condensate so condensate drains from the low point in every installed valve orientation. Trapped condensate reduces heat transfer and can impose mechanical loads during startup. |
| jbc access and spacer rule | Preserve access to every lug, flange bolt, packing adjustment, actuator fastener, and valve-removal path. The jacket must not become a structural spacer between the valve and mating flanges. |
| jbc thermal expansion effects | Excessive or uneven heating can change bearing clearance, seat contact, disc alignment, operating torque, and shutoff performance. Account for jacket mass, steam piping loads, insulation mass, and thermal movement. |
| jbc purpose designed jacket | A purpose-designed jacketed valve or manufacturer-approved removable jacket avoids uncontrolled alteration of the original body. |
| jbc least intrusive selection | Select the least intrusive method that holds every deposit-prone surface above the defined target. |
| jbd tail gas steam jacket | Tail Gas Butterfly Valves are equipped with steam jackets to prevent media from solidifying. |
Scope & source notes
| jacketed flange oversize | Jacketed flange oversize: OEM pages state jacketed connecting flanges run one to two nominal sizes above the standard butterfly valve, while line-size full-jacket executions keep standard flanges via tapped bolt-hole inserts - coverage style determines whether flanges grow. |
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| standards layering | Standards layering: butterfly product standards (API 609, MSS SP-68, EN 593, ISO 5752/EN 558 face-to-face, API 598/ISO 5208 testing) and jacket-fabrication standards (ASME B16.10/B16.34, B31.1/B31.3 jacket hydro, API 598 process side) address different layers of the same jacketed valve; face-to-face is frequently "ISO 5752 or approved manufacturer drawing". |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
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 should a quotation inquiry for jacketed butterfly 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.
Which size and pressure rating are available in jacketed butterfly valves?
A verified size and pressure rating range for this valve is not published on this page yet — the applicable size and pressure rating for your duty is proposed and confirmed during quotation. Send the service conditions with the inquiry and the selection is stated in the offer.
Which body material are available in jacketed butterfly valves?
A verified body material range for this valve is not published on this page yet — the applicable body material for your duty is proposed and confirmed during quotation. Send the service conditions with the inquiry and the selection is stated in the offer.
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