Cast Steel WCB Lined PTFE Worm Gear Wafer Butterfly Valve D371F46 Overview
The cast steel WCB lined PTFE worm gear wafer butterfly valve D371F46 is a manual isolation valve for corrosive process lines where a carbon steel pressure shell and full fluoroplastic wetted surfaces are required in a compact wafer envelope. Manufactured by Trekre Valve, this cast steel lined butterfly valve combines a WCB body with moulded PTFE, PFA or FEP lining on the bore, disc faces and seat lands, plus a worm gear reduction drive for controlled 90-degree rotation. The wafer body clamps between two pipeline flanges, reducing axial space on chemical transfer headers, pump skids and wastewater treatment manifolds compared with double-flanged patterns.
Construction and design features
Connection type: wafer (clamped between two flanges with through-bolts; lug wafer variants available on request)
Structure: centerline disc with two-piece cast steel body and continuous fluoroplastic lining on bore, disc faces and seat lands
Size range: 2″ to 24″ (DN50 to DN600) for standard wafer patterns; larger sizes available on project request
Pressure rating: PN10 and PN16; Class 150 on ANSI flange pairs (size and lining grade dependent)
Body material: cast carbon steel WCB with external paint or epoxy coating for general industrial environments
Lining options: PTFE, PFA or FEP selected for media compatibility, permeation resistance and temperature duty
Operation: worm gear handwheel with self-locking reduction for controlled opening and closing torque
Temperature range: -29°C to 180°C depending on lining material and continuous exposure conditions
Standards: GB/T 12238, HG/T 3704 lined valve specifications, API 609 Category A where applicable
Cast steel body with fluoroplastic corrosion barrier
Corrosive services attack valve internals from the bore outward while ambient humidity and wash-down chemicals can attack external steel surfaces on poorly specified valves. In this cast steel WCB lined PTFE worm gear wafer butterfly valve, the WCB body provides structural strength for flange bolt loads at a lower material cost than stainless equivalents, while PTFE, PFA or FEP forms a continuous barrier between the flowing fluid and all wetted steel surfaces including the body channel, disc faces and seat ring.
PTFE offers broad chemical inertness against strong mineral acids, caustic solutions and mixed solvents at moderate temperature. PFA provides improved permeation resistance and smoother surfaces for sticky polymers, chlorinated compounds or process fluids where trace metal contamination must be avoided. FEP suits applications where melt-processed lining uniformity at flange transitions and wafer body edges is critical. The lining is moulded under factory conditions rather than applied as a field wrap, ensuring uniform thickness where flange gaskets compress against the wafer faces.
Wafer installation and pipeline space savings
Wafer butterfly valves install between two pipeline flanges with through-bolts that pass outside the valve body. The short face-to-face length reduces overall piping envelope on sulphuric acid transfer lines, hydrochloric acid dilution headers, phosphoric acid circulation and solvent recovery manifolds where multiple valves sit in sequence. Compared with lug or double-flanged patterns, wafer bodies minimize material cost and simplify replacement when flange standards and pressure ratings remain unchanged.
Install the valve with the disc slightly open to protect lined seat edges during flange bolt-up. Use full-length bolts sized for the flange rating and gaskets compatible with the chemical service — PTFE envelope or spiral wound as specified. Tighten flange bolts in a star pattern to avoid seat distortion. Trekre Valve confirms face-to-face dimension, bolt circle and gasket seating width against the flange standard on the data sheet before shipment from our Wuxi manufacturing facility.
Worm gear drive and operating torque
Large bore lined butterfly valves require significant breakaway torque to unseat the fluoroplastic seal line after periods in the closed position, especially when line pressure or media deposits add friction. A worm gear reduction mounted on the stem converts moderate handwheel effort into the torque needed to rotate the disc through 90 degrees without sudden jerking that could damage the lining at the seat edge.
The self-locking worm gear prevents back-driving from line torque on partially open valves in high-velocity services. Handwheel direction, open and closed position stops, and optional mechanical position indicator are factory-set and documented on the nameplate. For buried or hard-to-reach installations, extension stem and floor box options can be quoted separately. Operating torque tables in the project submittal include breakaway and running values at rated differential pressure with margin for aged gaskets and scale buildup.
Fluoroplastic lining selection for PTFE, PFA and FEP duty
When the process specification names PFA or FEP rather than standard PTFE, the choice usually reflects temperature margin, permeation limits or surface finish requirements rather than a generic corrosion label. For hot corrosive condensate, mixed acid streams or chlorinated solvents, confirm chemical compatibility and permeation limits using data for the actual lining grade, complete lining construction and operating conditions. A polymer name alone does not establish long-term permeation performance or a universal preference for PFA over PTFE. FEP lining suits lower-temperature acid transfer and caustic circulation where melt-processed uniformity at the wafer gasket lands simplifies field assembly.
The disc seal line engages the lined seat without exposing bare metal, maintaining shut-off performance per project leakage criteria documented in the test report. Do not use the valve for throttling service beyond the partial-open limits defined on the data sheet — lined centerline discs are intended primarily for on-off isolation.
Typical applications and industry sectors
Chemical plants deploy cast steel WCB lined PTFE wafer butterfly valves on sulphuric acid transfer, hydrochloric acid dilution headers, phosphoric acid circulation and solvent recovery manifolds where corrosive fluids demand fluoroplastic protection in a compact wafer envelope. Chlor-alkali facilities isolate brine, caustic and chlorine compound streams on horizontal runs where painted WCB external surfaces suit indoor or sheltered outdoor installations.
Water and wastewater treatment facilities use lined wafer butterfly valves on sodium hypochlorite dosing, ferric chloride feed and polymer injection headers. Pulp and paper bleaching stage shutoff, metal finishing acid rinse lines and fertilizer plant acid handling are additional sectors where wafer mounting and worm gear manual operation replace bare steel valves that would corrode within months. Power plant FGD scrubber recycle isolation and general industrial acid-alkali piping also specify D371F46 pattern valves when cost-effective carbon steel shells with full lining are acceptable for the external environment.
Installation, maintenance and inspection
After installation, cycle the valve fully open and closed under no-flow conditions to verify smooth worm gear operation and correct disc orientation. Introduce process fluid gradually and inspect flange joints and stem packing for leakage. Periodic maintenance includes handwheel lubrication per site procedure, stem packing adjustment if needed, and visual inspection of external paint where wash-down chemicals are used.
Store spare lined wafer valves with the disc in the slightly open position to avoid permanent seat compression set during long warehouse periods. Before returning a valve to service after extended storage, inspect gasket faces for lining damage at bolt holes and verify worm gear backlash remains within factory tolerance. Avoid steam cleaning above the lining temperature limit specified on the nameplate.
Selection and ordering information
When specifying this cast steel lined PTFE wafer butterfly valve, provide medium name and concentration, design temperature and pressure, nominal size, flange standard (ANSI, DIN, JIS or GB), lining material preference (PTFE, PFA or FEP), and any extension stem or gear box orientation requirements. Confirm whether the installation requires dead-end service rating on one flange side — wafer valves generally rely on both flanges for retention. Trekre Valve factory tests each lined butterfly valve for seat leakage and handwheel operation prior to shipment.
Product parameters summary
Valve type: cast steel WCB lined PTFE worm gear wafer butterfly valve D371F46
End connection: wafer (clamped between flanges)
Body: cast carbon steel WCB
Lining: PTFE, PFA, FEP
Disc: lined steel with fluoroplastic overlay
Seat: moulded fluoroplastic integral with body liner
Actuator: worm gear handwheel, self-locking
Size: DN50–DN600 (2″–24″)
Pressure: PN10 / PN16; Class 150
Temperature: -29°C to +180°C (lining dependent)
Applicable media: acids, alkalis, solvents, chlorine compounds, wastewater and corrosive process fluids
Manufacturing: Trekre Valve, Wuxi, China
Frequently Asked Questions
Does the WCB body mean the process fluid contacts bare carbon steel?
The page describes a lined configuration, but the actual coverage must be confirmed on the wetted-parts specification. Ask for the lining, disc and sealing arrangement for the ordered valve rather than relying only on the body-material designation.
What should I provide when replacing an existing D371F46 wafer valve?
Send the existing valve identification, size, flange and face-to-face dimensions, operator position and service conditions. Request confirmation of the selected replacement drawing and lining grade before purchase.
How do I obtain the correct replacement liner or sealing parts?
Provide the valve identification and photographs or existing part references and request the parts approved for that exact assembly. Do not assume parts are interchangeable across body materials, sizes or lining grades.