Worm Gear Lug Soft Seal Butterfly Valve D372X Ductile Iron Stainless Disc
Worm Gear Lug Soft Seal Butterfly Valve D372X Ductile Iron Stainless Disc Specifications
The D372X worm gear lug soft seal butterfly valve is a quarter-turn isolation valve for water, air, and low-abrasive industrial fluids where threaded lug bolting and planned maintenance access matter more than the shortest possible face-to-face length. Trekre Valve manufactures this concentric lug butterfly valve with ductile iron, carbon steel, or stainless steel bodies, a stainless or ductile iron disc working against an elastomer seat, and a worm gear operator sized for the stated differential pressure. Fouten Valve application engineers can confirm body alloy, seat polymer, lug drill pattern, and accessory list against the pipeline flange standard before release from our Wuxi factory.
Overview and lug-type connection
Lug butterfly valves carry tapped or through holes in body ears so each flange joint can use its own bolt set. That arrangement supports dead-end service only when the manufacturer approves the bolting pattern, pressure class, and flow direction for the offered design. It also helps maintenance teams remove one side of the piping while the opposite flange line stays undisturbed, provided isolation and safety rules on site allow the work.
The D372X model designation identifies a soft-seated, concentric disc geometry with manual worm gear operation. Suffix letters on the order document spell out pressure class, body material, and seat polymer when a project requires a specific code such as D372X-10Q or D372X-16P. Compare lug hole count, thread form, flange drilling, facing, gasket type, and bolt length against the approved drawing before material release. Nominal diameter alone does not prove interchangeability between standards or between vendors.
Structure, disc, and soft seal
The valve assembly includes a lug-type body, disc, elastomer seat ring, stem, upper and lower bushings, packing gland, and worm gear head. In the concentric soft-seal layout, the stem axis passes through the disc center. Closing torque presses the disc edge into the resilient seat to build sealing stress. Opening rotation lifts the disc away from the seat line early in the stroke, which limits scrubbing on clean media services.
Seat options commonly include EPDM for water and moderate-temperature air, NBR for oil-tolerant water and compressed air, silicone for food-grade water where the material certificate matches the duty, and FKM where higher temperature or selected chemicals appear in the fluid analysis. Shutoff acceptance follows the test method named on the purchase order; Trekre documents seat results on the factory test sheet rather than quoting a universal leakage class in place of that record.
The disc is typically stainless steel 304 or 316 for corrosion resistance on the wetted face, or ductile iron with a stainless overlay when cost and weight targets favor a composite plate. The stem uses stainless steel with anti-blowout retention in the lower bearing pocket. Self-lubricating bushings reduce friction so handwheel or gearbox input torque stays within the operator rating after packing adjustment.
Worm gear operator, handwheel, and ISO 5211 interface
Standard supply pairs the lug body with a worm gear operator chosen from break and run torque at maximum differential pressure, plus an agreed safety factor. The gear set converts many handwheel turns into controlled disc rotation, which protects seat edges during final closure on larger sizes. A position indicator on the gearbox cover helps operators align with open, closed, and intermediate marks during commissioning.
Applicable sizes often include an ISO 5211 mounting pad so a pneumatic or electric actuator can replace the worm gear head later if the plant adds automation. Any change in operator type requires a fresh torque review because break torque rises when seats age or when line pressure increases above the original design point. Trekre can quote bare stem, extended stem, or chain wheel extensions when underground or insulated lines need local access.
Body materials and pressure-temperature limits
Body castings are offered in ductile iron QT450-10 or QT400-15 for municipal and building services, carbon steel WCB for industrial water and air, and stainless CF8 or CF8M when chloride fogging or mild chemical exposure affects external surfaces as well as the bore. Pressure ratings commonly include PN10 and PN16, with Class 150 flange pairs on ANSI projects. Nominal sizes from DN50 through DN1200 appear on standard price lists; confirm casting availability and gear size for extreme diameters at quotation stage.
Temperature limits depend on the seat polymer and packing set. EPDM seats often serve from roughly −30 °C to +120 °C in water duty when the fluid chemistry matches the rubber grade. NBR seats typically serve lower temperature compressed air and oily water within the band stated on the material data sheet. Do not exceed the combined pressure-temperature table for the complete valve assembly; the body rating alone does not define seat life at the upper temperature edge.
Product parameters
| Item | Specification |
|---|---|
| Model | D372X worm gear lug soft seal butterfly valve |
| Structure | Lug type, concentric soft seat |
| Size range | DN50 – DN1200 (NPS 2 – 48) |
| Pressure class | PN10, PN16; Class 150 as specified |
| Body material | Ductile iron, WCB, CF8, CF8M |
| Disc / seat | Stainless or ductile iron disc; EPDM, NBR, silicone, or FKM seat |
| Operation | Worm gear with handwheel; ISO 5211 pad on applicable sizes |
| Design reference | GB/T 12238, API 609 Category A, project flange standard |
| Test | Shell and seat per agreed standard; leakage per test report |
Table values show common optional combinations. Final body, seat, lug drill, operator, and flange details are confirmed on the Trekre or Fouten technical agreement, nameplate, and test report for the ordered tag number.
Typical applications
Specify the D372X worm gear lug soft seal butterfly valve on building chilled and hot water branches, cooling tower isolation, municipal pump headers, food-grade water transfer where elastomer certificates match the hygiene plan, paper mill white water zones, and general plant air headers where soft seats and infrequent manual operation are appropriate. The lug body fits rack layouts that must allow one-sided removal during outage windows.
Compared with wafer soft-seal valves on the same line size, lug ears provide distinct bolting paths for each flange and clearer maintenance planning on dead-end legs when the manufacturer approves the duty. Compared with metal-seated triple-offset lug valves, the soft seat targets lower torque and bubble-tight water shutoff rather than high-temperature dry gas service. Media with sharp solids, high velocity slurry, or sustained throttling beyond the manufacturer partial-open limit should be reviewed before selecting a concentric soft-seal disc.
Installation, commissioning, and service
Install the valve with the disc slightly open to protect the seat edges while flange bolts are tightened in a cross pattern. Use gaskets compatible with the fluid and flange facing. Align pipe ends so lug threads are not cross-loaded by bolt pull-in. Stroke the valve locally through full open and closed positions before applying process pressure. Record gearbox indicator alignment against the isolation procedure.
Periodic inspection should cover seat faces for cuts, stem packing for weeping, and gear lubrication per the operator manual. Replace seat rings during planned outages when closure leakage exceeds the operating procedure allowance. Store spare valves with the disc marginally open to avoid long-term seat compression set in warehouse stock.
What data should I send for a D372X quotation?
Provide medium composition, design pressure and temperature, nominal size, flange standard and facing, lug thread or through-hole requirement, end-of-line duty if applicable, and any inspection document list. Trekre Valve engineers return a bill of materials with body and seat materials, gear operator model, and bolt guidance for the lug pattern.
Can the valve be used for throttling service?
Some concentric soft-seal discs tolerate partial opening for balanced flows, but cavitation, noise, and seat wear rise at high pressure drops. Share the flow curve and differential pressure so the team can confirm whether a high-performance offset design fits better.
Is welding allowed on the lug body?
Do not weld the valve into the pipeline. Lug bodies rely on flange gaskets and mechanical bolting; welding heat damages elastomer seats and voids standard warranty terms for soft-seal products.
Worm Gear Lug Soft Seal Butterfly Valve D372X Ductile Iron Stainless Disc Manuals
Downloads: Worm Gear Lug Soft Seal Butterfly Valve D372X Ductile Iron Stainless Disc.pdf
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