Material Characteristics And Applications Of Ptfe-lined Wafer-type Pneumatic Control Butterfly Valves

A PTFE lined butterfly valve with a wafer body seals corrosive media by covering the bore and disc with a liner. Install by centering the body between two pipe flanges, tightening through-bolts in a cross pattern, and cycling the disc before pressurizing. The wafer connection covers PN10, PN16, and 150LBS ratings. The compact body cuts weight on crowded skids.

Wafer Body and Compact Installation

The wafer body has no end flanges of its own. It sits between two pipe flanges and is held by through-bolts. The body thickness is a fraction of a double-flanged design.

• Saves face-to-face length on the line

• Reduces load on pipe supports

• Fits where a full flanged valve cannot

• Lower weight than flanged bodies

The body locates on the pipe bore through a raised face or a centering ring. Correct centering keeps the disc clear of the pipe wall. Misalignment causes disc rub and liner wear.

Liner Materials and Chemical Isolation

The liner forms a continuous barrier over the body bore and disc. PTFE covers strong acids and bases across -29°C to 180°C. PFA handles similar chemistry up to 200°C. FEP suits lower-temperature service to 150°C.

A lining butterfly valve body keeps the process fluid away from the metal casting. The disc also carries a liner cover, so both sealing surfaces resist attack.

Pneumatic Actuator and Flow Regulation

The actuator converts air pressure into a quarter-turn stroke. A positioner adjusts the disc angle to match a control signal, so the valve regulates flow rather than only open and close. Spring-return units close on air loss, while double-acting units hold position. A positioner enables modulating duty, and the low-friction liner keeps torque steady across the stroke. A lined butterfly valve with a positioner suits modulating duty on corrosive lines.

Installation and Maintenance

1. Confirm the flange rating and face-to-face length.

2. Center the wafer body on the pipe bore.

3. Fit through-bolts and tighten in a cross pattern.

4. Connect air supply through a filter regulator.

5. Cycle the disc through full travel before pressurizing.

A lining butterfly valve with a damaged liner leaks at the seat. Replace the liner when cuts, swelling, or hardening appear. Check the disc edge for nicks that tear the seat.

Common Applications

Lined butterfly valves serve chemical dosing and transfer lines, acid and caustic service, pharmaceutical solvent handling, water treatment chemical feed, and petrochemical corrosive streams. The wafer body suits tight spaces on skids and headers. A ptfe lined butterfly valve with a pneumatic actuator fits automated flow control where a flanged body cannot.

Field Notes

• Store spare liners flat and away from direct sunlight.

• Use a coalescing filter on the air supply to protect the actuator.

• Check disc edge condition before fitting a new liner.

• Re-torque through-bolts after the first thermal cycle.

• Keep a spare gasket set matched to the liner compound.

Record each liner replacement date to track service life against the process medium. A simple log helps predict when the next change is due. Mark the flange bolts after final torque so a quick visual check shows if any have moved.

FVF PTFE Lined Wafer Type Pneumatic Regulating Butterfly Valve

• FVF lined butterfly valve can realize  bi-directional flow under the maximum working pressure.Since the valve port corresponds to the piping diameter, a high flow capacity is guaranteed.
• It features ease of maintenance, repeatable on-off, long life durability.
• It is commonly used in the power generation, brewing, water and food industries and suitable for both gaseous and liquid service. Typically applied in chemical/petrochemical process, food and beverage, and pulp and paper etc.
• They are available with Wafer style or Lug style 150# ANSI flange connections. They can be equipped with a manual lever or can be actuated with electric or pneumatic actuators. A full range of accessory items are available including limit switches, solenoid valves, positioners and manual override devices.