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Gansu Juxiang Fluoroplastics Technology Co.,Ltd. supplies the PTFE Lined Butterfly Valve Series Products manufacturer range as part of a wider fluoroplastic product range that begins with PTFE, modified PTFE, PFA and PVDF stock and ends with finished sealing and flow-control components. Each valve isolates the wetted path from the metal body with a moulded fluoroplastic liner, and the seat, stem seal and companion flange gaskets come from the same material family we produce at our Yumen, Gansu Province works.
The series is built for isolation and throttling duty on aggressive, high-purity or scaling service where carbon steel and standard elastomers will not survive a maintenance interval. Because the liner and seat compounds are ours, the valve is matched to the medium rather than to a catalogue default.
Range and Configuration
Bodies are ductile iron, cast steel or stainless steel; the liner is the component that decides service life, and it is specified together with the seat rather than separately. Wafer, lugged and double-flanged patterns cover the usual installation constraints, and the top flange is machined for direct actuator mounting.
- Body styles: wafer, lugged and double-flanged, with face-to-face dimensions to the EN 558 and API 609 series used on the line.
- Body materials: ductile iron GGG40, carbon steel WCB, stainless CF8/CF8M, and duplex grades for seawater and brine.
- Liner: virgin PTFE, modified PTFE, or PFA/FEP where permeation or temperature rules out standard PTFE.
- Disc: ductile iron or stainless, with PTFE or PFA encapsulation across the wetted faces.
- Seat: PTFE or modified PTFE, elastomer-backed where bubble-tight closure is required at higher differential pressure.
- Operation: lever, worm gear, pneumatic double-acting or spring-return, and electric with open/close or modulating control.
Application Fit by Service Condition
The series is used on chemical transfer and dosing lines, storage-tank outlets, water and wastewater headers, brine and hypochlorite systems, pickling and plating circuits, pulp stock, and high-purity chemical distribution in pharmaceutical and semiconductor plants. The duty is always the same three-part problem: keep the medium off the metal, keep the seat tight across cycles, and keep operating torque inside what the actuator can deliver.
| Service condition | Liner and seat selection | Configuration notes |
|---|---|---|
| Mineral acids, alkalis, hypochlorite at ambient to moderate temperature | Virgin PTFE liner, PTFE seat | Wafer body for tight pipe runs; anti-static stem arrangement where flammable vapour is present |
| Hot chemical duty near the liner limit | Modified PTFE or PFA liner | Pressure and temperature derated together; gasket grade matched to the same envelope |
| High-purity and semiconductor wet service | PFA liner, PFA-encapsulated disc | Deionised rinse before packing; low-extractable seat grade |
| Slurries, crystallising and scaling media | PTFE seat with elastomer backing | Flush port or cavity-free seat area to stop solids collecting |
| Vacuum and high-cycle modulating duty | Modified PTFE liner with backup ring | Permeation-resistant liner; stem seal and bearing checked for cycle life |
| Seawater, brine, cooling water | PTFE liner, duplex disc and stem | Fastener and external coating grade matched to the site atmosphere |
Liner, Seat and Disc: What Sets Service Life
PTFE is inert across almost the whole pH range, but it creeps, permeates and fatigues under cycling. Those behaviours, not chemical resistance, decide how a lined butterfly valve performs after two or three years in the line.
- Temperature and pressure derate together. A liner that holds at ambient pressure will not hold the same pressure at 150 °C; the operating envelope follows the liner grade, not the body rating.
- Permeation matters on vacuum and hot aggressive media. PFA or modified PTFE liners reduce the rate at which the medium reaches the body casting.
- Seat design sets shut-off class. A soft PTFE seat closes bubble-tight at low differential pressure; elastomer backing extends that to higher ratings but narrows the chemical and temperature window.
- Stem sealing is the second leak path. Live-loaded PTFE chevron packing or a PTFE/elastomer combination is selected against the medium and the number of cycles per shift.
- Torque is a design output. Seat interference, liner thickness and actuator sizing are checked as one set so the valve strokes cleanly at line pressure, including seat grades based on filled PTFE compounds where wear resistance is the priority.
Specifications We Confirm Before Production
Size, pressure class and material are not fixed by the series; they are set by the line. The matrix below is the working basis for a released order.
| Parameter | Detail we need | Effect on the valve |
|---|---|---|
| Nominal size and face-to-face | DN or NPS, EN 558 or API 609 series | Sets body pattern and liner mould |
| Pressure class and flange drilling | PN10/16/25, Class 150/300, drilling standard | Body wall, flange thickness, bolt pattern |
| Body and disc material | Ductile iron, WCB, CF8/CF8M, duplex | Pressure containment and corrosion allowance |
| Liner and seat compound | PTFE, modified PTFE, PFA; seat hardness | Chemical compatibility, temperature limit, shut-off class |
| Operating envelope | Design pressure, design temperature, cycles per day | Liner grade, seat pre-load, actuator torque |
| Medium | Chemistry, concentration, solids content, viscosity | Seat type, flush requirement, disc style |
| Actuation | Manual, pneumatic, electric; fail position; control signal | Mounting interface, bracket, stem adaptor, accessory set |
| Testing and documentation | Test standard, witness points, certificate package | Inspection hold points and release paperwork |
| Marking and packing | Tag numbering, coating, export packing | Delivery scope and site identification |
Actuation and Line Integration
Actuators mount on an ISO 5211 top flange, and we size the bracket, stem adaptor and coupling as one assembly so the valve can be stroked on the bench before dispatch. Pneumatic double-acting and spring-return units are supplied with solenoid valves, filter regulators, limit switch boxes and, for modulating duty, a positioner.
- Fail position is defined at enquiry: spring-to-close for isolation duty, spring-to-open for cooling and relief paths.
- Electric actuation is specified with site voltage, control voltage and signal type; 4–20 mA modulating duty needs a different actuator from open/close duty.
- Filtered, dry air at the stated pressure keeps piston seals and solenoids alive; air quality is part of the actuator selection, not an afterthought.
- Commissioning covers stroke direction, limit switch setting, torque switch setting and a seat leak check at line conditions.
Testing, Documentation and Acceptance
Each valve is pressure-tested before packing: shell test at 1.5 times the rated pressure and seat test at 1.1 times, recorded against the tag number. Lining integrity is checked visually and by holiday test on the wetted surface, with liner thickness measured at the flange faces and the seat bore.
- Dimensional and flange drilling check against the line specification before assembly is closed out.
- Operating torque verified against actuator output at the specified differential pressure.
- Documentation package: material certificates for body, disc, stem and liner, pressure test reports, lining inspection record, installation and operating instructions, spare parts list.
- Marking covers size, pressure class, body and liner material, tag number and flow arrow; packing protects flange faces, stem and actuator, with export cases sized for site handling.
Information We Use to Configure Your Solution
A quotation that can be released to production without a second round of questions starts from a complete duty description. These are the inputs we work from:
- P&ID or line list with tag numbers, quantity per size and spare allowance.
- Line size, pressure class, flange standard and face-to-face requirement.
- Medium, concentration, solids content, and the design temperature and pressure envelope.
- Flow rate, allowable pressure drop and required shut-off class.
- Actuation schedule: type, fail position, control signal, accessory set and terminal box details.
- Test standard, witness points, documentation language and certificate requirements.
- Site coating, tagging, packing and delivery sequence, including any spares to travel with the first shipment.
Frequently Asked Questions
What sizes and pressure classes does the series cover?
Size and pressure class are set per order rather than by a fixed catalogue window. We build to the DN or NPS and the PN or Class in the enquiry, with wafer, lugged or double-flanged bodies to the face-to-face series the line uses. Line size, flange standard and design pressure define the body configuration.
Can the valve be used on vacuum service?
Vacuum is a permeation problem before it is a pressure problem. A standard PTFE liner can lift away from the body under vacuum, so we specify a modified PTFE or PFA liner with a backup ring and confirm the vacuum level and temperature at enquiry.
Which liner suits hot acid duty?
Temperature, concentration and pressure have to be read together. Standard PTFE covers most ambient and moderate-temperature acid service; above roughly 120 °C, or where permeation through the liner is a concern, modified PTFE or PFA is the better fit, and the pressure envelope is derated to match.
Are gaskets and seat spares supplied with the valves?
Yes. Expanded PTFE reinforced flange gaskets, seat kits and stem seals can travel in the same delivery because we produce them, which keeps the joint materials consistent with the liner and avoids mixing grades on site.
