The worm gear steel lined PTFE wafer butterfly valve is a corrosion-resistant quarter-turn control valve designed for pipelines carrying aggressive acids, alkalis, oxidizing media and organic solvents where the suitability of metallic and lined wetted surfaces must be assessed against the actual medium and operating conditions. Manufactured by Trekre Valve at our Wuxi facility, this lined wafer butterfly valve combines a cast steel body with a full fluoropolymer lining on the body bore, disc and stem contact zones so that only the lining material contacts the process fluid during operation.
Also known as a gear operated PTFE lined clamp butterfly valve, the two-piece split body integrates the valve body, seat and lining in a unified corrosion barrier. During operation, the plastic-lined valve seat and fluoropolymer-coated disc are the sole wetted sealing surfaces. Confirm compatibility of the exact lining grade, seat energizer and other wetted components with the actual chemical, concentration, temperature, pressure and exposure conditions. The lining designation alone is not approval for every acid, oxidant or solvent. The forged disc and stem assembly carries an evenly bonded lining layer, producing a smooth internal bore with low flow resistance, high Cv values and moderate operating torque.
Construction and sealing design
Connection type: wafer (clamp) butterfly valve installed between two pipeline flanges with through bolts and gaskets; compact face-to-face length suitable for ANSI Class 150, PN10/PN16 and JIS 10K flange pairs when dimensional tables are confirmed for the nominated standard.
Structure: two-piece cast steel split body with integrated fluoropolymer lining; disc and stem forged as one unit with uniform lining coverage on all wetted surfaces; four-stage sealing arrangement with elastic liner seat matching for bubble-tight shut-off on water and low-leakage closure on chemical services.
Sealing form: PTFE, PFA, FEP or PCTFE full lining on body bore, disc faces and stem seal zone; heat-resistant SI rubber seat ring option for elevated temperature chemical transfer within the lining temperature envelope.
Operation: worm gear manual operator with self-locking reduction for sizes where hand torque exceeds practical limits; handle lever operation available on smaller nominal diameters; pneumatic and electric actuators mount via ISO 5211 top flange connection plate.
Body material: ASTM A216 WCB cast carbon steel shell providing structural strength; stainless steel CF8/CF8M body options for higher corrosion resistance on the exterior and for specific project specifications.
Lining material: PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy), FEP (fluorinated ethylene propylene) or PCTFE selected according to medium concentration, temperature and permeation requirements.
Nominal size and pressure rating
Nominal diameter range: DN50 (2 inch) through DN600 (24 inch) depending on pressure class, lining type and actuator torque envelope. Pressure rating: ANSI Class 150; EN PN10 and PN16; JIS 10K when flange drilling and face-to-face dimensions are confirmed against the nominated piping standard.
The worm gear operated configuration is typically specified for sizes from DN100 upward where manual quarter-turn torque at rated differential pressure exceeds comfortable hand operation limits. Smaller sizes may be supplied with handle lever operators while retaining the same lined trim and ISO 5211 actuator mounting pad for future automation.
Bidirectional shut-off capability is maintained within the rated pressure-temperature envelope of the selected lining material. For throttling or modulating duty, confirm velocity limits and cavitation risk at partial disc openings, particularly on slurry or particle-laden chemical streams where lining erosion at the downstream seat quadrant may occur over extended service.
Drive methods and actuation
Worm gear operation provides self-locking manual control without auxiliary power, making this steel lined PTFE wafer butterfly valve suitable for isolation points on chemical transfer headers, tank farm manifolds, acid dosing skids and remote valve stations where electric or pneumatic supply is unavailable or undesirable.
The ISO 5211 mounting pad on the worm gear housing accepts direct-coupled pneumatic spring-return or double-acting actuators and electric quarter-turn actuators when remote or automated operation is specified. Handle lever variants on DN50–DN150 provide immediate local on/off control with indexed open and closed stops.
Applicable working conditions and industries
This worm gear steel lined PTFE wafer butterfly valve is specified for sulfuric acid transfer, hydrochloric acid dosing, phosphoric acid processing, chlorine dioxide bleaching circuits, sodium hypochlorite disinfection lines, mixed acid blending, solvent recovery headers and general corrosive chemical utility branches where metal-seated or unlined valves cannot meet service life expectations.
Typical industries include chlor-alkali plants, phosphate fertilizer production, pulp and paper bleaching, electroplating and surface treatment, pharmaceutical API synthesis, semiconductor wet chemical distribution, municipal water treatment chemical injection and general EPC packages requiring documented fluoropolymer lining compatibility for turnover documentation.
Use the documented pressure-temperature rating of the selected complete valve assembly. Do not derive its operating range from the lining polymer name alone; request the product-specific limits for the body, lining, energizer and seals. Confirm lining permeation rates for permeating solvents such as certain chlorinated hydrocarbons when specifying PFA versus PTFE for long-term storage or batch transfer duty.
Product parameters
Valve type: worm gear steel lined PTFE wafer butterfly valve
Model reference: D371F46 / D371F4 (project-specific)
Size range: DN50–DN600 (2″–24″)
Pressure rating: ANSI Class 150, PN10/PN16, JIS 10K
Body: WCB cast carbon steel, CF8/CF8M stainless steel
Lining: PTFE, PFA, FEP, PCTFE full lining on body and disc
Seat: PTFE/PFA lined with SI rubber backup ring
Disc and stem: carbon steel or stainless steel with full fluoropolymer lining
Operation: worm gear / handle lever / pneumatic / electric actuator
Top flange: ISO 5211 for actuator mounting
Design standard: GB/T 12238, API 609 Category A
Test standard: API 598, GB/T 13927
Leakage class: bubble-tight on water at rated test pressure
Lining selection and chemical compatibility
PTFE lining offers broad chemical resistance and economical supply for sulfuric acid, hydrochloric acid and general inorganic acid services at moderate temperatures. PFA lining provides improved high-temperature stability and lower permeation for hot corrosive media and certain organic solvents. FEP lining delivers smooth surface finish and excellent release properties for sticky or crystallizing chemical products. PCTFE is selected for specialized low-permeation duties where project specifications require enhanced barrier performance.
The integrated two-piece body design ensures the lining layer remains continuous across the body split line, eliminating crevice corrosion paths that occur when separate seat rings and unlined body bores are used in aggressive services. Trekre Valve application engineers review your medium analysis, concentration, temperature and cycle frequency to recommend the appropriate fluoropolymer grade and provide dimensional drawings for project documentation packages.
Selection and installation notes
Confirm upstream and downstream flange standards, gasket type and bolt length before ordering wafer lined butterfly valves; through-bolt sets must span both flanges plus the valve body without bottoming. Install with the disc fully open during pipeline flushing to protect the lining from debris impact and welding spatter. Avoid lifting the valve by the worm gear handwheel or actuator coupling to prevent misalignment of the stem seal.
For horizontal pipelines, orient the stem upward or horizontal to prevent condensate accumulation in the packing zone on steam-out or thermal cycling services. Allow clearance for worm gear rotation and maintenance access to the stem gland. Do not exceed the rated torque on the worm gear input during commissioning; verify disc travel stops before applying line pressure.
Quality assurance and delivery
Each worm gear steel lined PTFE wafer butterfly valve undergoes shell hydrostatic test, seat closure test on water and operational torque verification before shipment from our Wuxi factory. Lining spark test or holiday detection is performed according to project requirements to verify lining integrity on all wetted surfaces. Material certificates for body castings, lining material records and pressure test reports are available for project turnover packages.
External surfaces receive primer or epoxy coating for corrosion protection during storage and transit. Contact Trekre Valve for competitive quotations on worm gear operated PTFE lined wafer butterfly valves for your chemical processing, water treatment or industrial corrosive media pipeline project.
Comparison with double flange and lug-type lined alternatives
Double flange lined butterfly valves provide stable pipeline connection for larger sizes and higher pipe loads but require greater face-to-face length and overall weight. Lug-type lined valves allow one-sided pipeline removal for maintenance in terminal or end-of-line positions. The wafer format minimizes space and weight when both flanges remain in place during service, making it the preferred choice for chemical skids, compact pipe racks and retrofit applications where flange spacing is constrained.
Compared with unlined resilient seated wafer valves, the full fluoropolymer lining extends service life in acids and oxidizing chemicals where EPDM or NBR seats would swell, degrade or fail within weeks. The worm gear operator reduces input torque compared with direct hand lever operation on larger sizes, protecting the lined stem seal from excessive torsional loading during frequent cycling duty.
Frequently Asked Questions
Does the quotation include a hand lever or the worm gearbox?
The title and description discuss different operating arrangements. Specify the required operator and ask for the exact assembly and scope of supply to be identified on the quotation and drawing.
Can I add an actuator later to the ISO 5211 interface?
Request the actual mounting and coupling dimensions and valve torque and travel requirements for the selected unit. Confirm the future actuator and any adapter or gearbox arrangement rather than treating the interface designation as universal interchangeability.
Which pipe and flange measurements matter for the lined wafer body?
Provide the mating flange details, pipe bore and available face-to-face space. Ask for confirmation of disc clearance and the lining-specific installation and fastener requirements for the chosen valve.