The ASCO explosion-proof solenoid valve pneumatic fluorine lined butterfly valve is a quarter-turn isolation and control assembly designed for hazardous-area chemical pipelines where corrosive fluids must be shut off remotely without exposing metallic wetted surfaces to the process medium. Manufactured by Trekre & Fouten Valve at our Wuxi facility, this pneumatic fluorine lined butterfly valve pairs a full fluoropolymer-lined valve body and disc with a pneumatic actuator and ASCO-rated explosion-proof solenoid valve for reliable on/off or modulating duty in Zone 1 and Zone 2 classified environments.
Fluorine lining on the body bore, disc faces and stem contact zone isolates cast steel or stainless steel structural components from acids, alkalis, chlorine compounds, oxidizing chemicals and solvent blends. The ASCO solenoid valve provides pilot air switching to the pneumatic actuator, enabling remote open and close commands from a control room or distributed control system while maintaining the electrical equipment protection level required for flammable gas or vapor atmospheres near the valve station.
Construction and sealing design
Connection type: wafer (clamp) or lug-type butterfly valve installed between pipeline flanges; compact face-to-face length suitable for ANSI Class 150, PN10/PN16 and JIS 10K flange pairs when dimensional tables are confirmed against the nominated piping standard.
Structure: two-piece cast steel split body with integrated fluoropolymer lining on all wetted surfaces; disc and stem assembly with uniform PTFE, PFA or FEP lining coverage; pneumatic actuator mounted via ISO 5211 top flange coupling with bracket and coupling kit sized for rated differential pressure torque.
Sealing form: full fluorine lining on body bore, disc and stem seal zone; elastic backup seat ring for bubble-tight shut-off on water test and low-leakage closure on chemical services within the lining temperature envelope.
Actuation: double-acting or spring-return pneumatic actuator; ASCO explosion-proof solenoid valve for pilot air direction; optional limit switch box and positioner for feedback and modulating control when project specifications require proportional flow regulation.
Body material: ASTM A216 WCB cast carbon steel or CF8/CF8M stainless steel shell providing structural strength for pipeline loads and actuator reaction forces.
Lining material: PTFE, PFA or FEP selected according to medium concentration, temperature, permeation rate and abrasion exposure on the disc downstream quadrant during throttling duty.
ASCO solenoid valve integration
The ASCO explosion-proof solenoid valve serves as the pilot switching element in the pneumatic control circuit. When the solenoid coil is energized, pilot air is directed to the actuator air port to drive the lined disc toward the open or closed position depending on the fail-safe configuration. De-energizing the solenoid vents or reverses pilot pressure so the actuator returns to the safe position defined in the instrument datasheet.
Explosion-proof solenoid valve selection must match the hazardous area classification, gas group, temperature class and ingress protection rating specified on the project electrical area drawing. Trekre & Fouten Valve supplies the pneumatic fluorine lined butterfly valve and actuator as an integrated package; the ASCO solenoid valve model, coil voltage, connection thread and certification markings are confirmed against purchaser instrument specifications before assembly and factory testing.
Typical instrument air supply pressure ranges from 0.4 to 0.7 MPa (4 to 7 bar). Filter-regulator-lubricator units upstream of the solenoid protect the pilot circuit from moisture and particulate contamination that could cause sluggish actuator response or internal corrosion of non-lined pneumatic components.
Nominal size and pressure rating
Nominal diameter range: DN50 (2 inch) through DN600 (24 inch) depending on pressure class, lining type, actuator size and available air supply torque. 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.
Actuator sizing accounts for maximum differential pressure across the closed disc, lining friction factor and a safety factor for supply pressure variation. Larger nominal diameters at higher pressure classes require higher torque pneumatic actuators and correspondingly larger ASCO solenoid valve flow coefficients to achieve rated stroke time from fully closed to fully open within the seconds specified on the valve datasheet.
Bidirectional shut-off is maintained within the rated pressure-temperature envelope of the selected lining grade. For throttling applications, confirm velocity limits and potential lining erosion at partial disc openings, particularly on slurry or particle-laden streams where the downstream seat quadrant sees concentrated flow impingement.
Applicable working conditions and industries
This ASCO explosion-proof solenoid valve pneumatic fluorine lined butterfly valve is specified for sulfuric acid transfer headers, hydrochloric acid dosing skids, chlorine dioxide bleaching circuits, sodium hypochlorite disinfection branches, phosphoric acid processing, solvent recovery manifolds and general corrosive chemical utility lines located in classified hazardous areas where electric motor actuators cannot be installed or where pneumatic fail-safe action is preferred.
Typical industries include chlor-alkali plants, petroleum and chemical refineries, pharmaceutical API synthesis, pulp and paper bleaching, electroplating and surface treatment, LNG and gas processing auxiliary chemical injection, offshore platform chemical service modules and EPC packages requiring documented fluoropolymer lining compatibility plus explosion-proof electrical equipment for zone-rated pipe racks.
Operating temperature range follows the selected lining grade: PTFE and FEP lined variants typically serve −20 °C to +120 °C; PFA lined variants extend to approximately +180 °C depending on medium and pressure combination. Confirm lining permeation rates for permeating solvents when specifying PFA versus PTFE for long-term storage or batch transfer duty in hazardous enclosures.
Product parameters
Valve type: pneumatic fluorine lined butterfly valve with ASCO explosion-proof solenoid valve
Model reference: D671F46 / D671F4 (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 full lining on body and disc
Seat: fluoropolymer lined with elastomer backup ring
Disc and stem: carbon steel or stainless steel with full fluorine lining
Actuator: pneumatic double-acting or spring-return
Solenoid valve: ASCO explosion-proof pilot valve (model per project spec)
Top flange: ISO 5211 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
Pneumatic control circuit layout
A typical control arrangement routes plant instrument air through a filter-regulator, then through the ASCO solenoid valve to the actuator air ports. Limit switch boxes mounted on the actuator stem provide open and closed position feedback to the distributed control system. Quick-exhaust valves or speed control mufflers may be added when stroke time limits are specified for emergency shutdown sequences.
Spring-return actuator configurations define the fail position on loss of air or loss of solenoid power. Double-acting actuators require two solenoid valves or a single four-way pilot valve for direction control and hold the disc in the last commanded position when air supply is interrupted unless a separate fail-safe logic interlock is provided.
All pneumatic tubing, fittings and solenoid valve enclosures in the hazardous area must comply with the same zone rating as the ASCO explosion-proof device. Trekre & Fouten Valve provides assembly drawings showing recommended tubing routes, condensate drain points and accessibility clearances for solenoid coil replacement without removing the lined valve from the pipeline.
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 release properties for sticky or crystallizing chemical products that might adhere to unlined metallic disc surfaces.
The integrated two-piece body design maintains lining continuity across the body split line, eliminating crevice corrosion paths that occur when separate seat rings and unlined body bores are used in aggressive services. Application engineers review medium analysis, concentration, temperature and cycle frequency to recommend the appropriate fluoropolymer grade before actuator and solenoid valve sizing is finalized.
Selection and installation notes
Confirm upstream and downstream flange standards, gasket type and bolt length before ordering wafer or lug 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. Mount the actuator and solenoid valve bracket with adequate clearance for maintenance access and coil wiring gland orientation per the hazardous area cable entry drawing.
For horizontal pipelines, orient the stem upward or horizontal to prevent condensate accumulation in the packing zone on thermal cycling services. Do not exceed rated actuator supply pressure during commissioning; verify disc travel stops and solenoid valve function at reduced pressure before applying full line differential across the closed disc.
Quality assurance and delivery
Each pneumatic fluorine lined butterfly valve undergoes shell hydrostatic test, seat closure test on water and actuator stroke 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. Factory acceptance testing of the ASCO solenoid valve pilot circuit with the assembled actuator confirms correct open and close response at nominal instrument air pressure.
Material certificates for body castings, lining material records, pressure test reports and actuator/solenoid assembly checklists are available for project turnover packages. External surfaces receive primer or epoxy coating for corrosion protection during storage and transit. Contact Trekre & Fouten Valve for quotations on ASCO explosion-proof solenoid valve pneumatic fluorine lined butterfly valve assemblies for your hazardous-area chemical processing or industrial corrosive media pipeline project.