Characteristics And Selection Of Fluorine-lined Pneumatic Ball Valves

A lined ball valve with full liner isolation uses a PTFE, PFA, or FEP layer to separate the process fluid from the metal body. The liner covers the body bore, flange faces, and ball surface. A pneumatic actuator drives the ball through a quarter-turn stroke. The flange connection mates with PN10, PN16, or 150LBS pipe flanges. This design resists corrosive media in chemical and pharmaceutical lines.

Full Liner Isolation Principle

The liner forms a continuous barrier between the fluid and the metal housing. PTFE covers strong acids, bases, and solvents across -29°C to 180°C. PFA handles similar chemistry up to 200°C. FEP suits lower-temperature service to 150°C.

• Liner covers body bore and flange faces

• Ball surface carries a PTFE cover

• Gasket matches the liner material

• Metal parts stay isolated from the media

A teflon lined valves body resists permeation and chemical attack. The liner thickness and molding method set service life under thermal cycling.

Flange Connection and Sealing

The valve body ends carry flange faces drilled to PN10, PN16, or 150LBS patterns. A gasket sits between the valve flange and the pipe flange. The liner extends over the flange face, so the gasket contacts the liner rather than bare metal.

Bolt torque compresses the gasket against the liner face. Even torque around the bolt circle keeps the seal tight. A lined valve with a damaged flange liner leaks at the joint.

Pneumatic Actuator Operation

The actuator converts air pressure into a quarter-turn stroke. Rack-and-pinion or Scotch yoke designs produce the torque curve. Spring-return units close the valve on air loss. Double-acting units hold position instead.

A lined ball valves body with a low-friction liner needs less torque to turn. That reduces air consumption and allows a smaller actuator. The choice follows the safe state for the process.

Installation and Maintenance

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

2. Align the valve with pipe flanges and tighten bolts in a cross pattern.

3. Connect air supply through a filter regulator.

4. Cycle the valve through full open and close before pressurizing.

5. Inspect the liner and gasket at scheduled intervals.

A lined valve with a damaged liner leaks at the flange or seat. Replace the liner and gasket when cuts, swelling, or hardening appear.

Common Applications

Lined ball valves serve lines that handle corrosive media. The liner protects the body from chemical attack where bare metal corrodes.

• Chemical dosing and transfer lines

• Acid and caustic service

• Pharmaceutical solvent handling

• Water treatment chemical feed

• Petrochemical corrosive streams

A lined ball valve with a pneumatic actuator suits automated dosing skids. The full liner extends body life and cuts maintenance.

Frequently Asked Questions

What does the liner isolate?
The liner covers the body bore, flange faces, and ball. It keeps the process fluid away from the metal housing.

Which liner suits strong acids?
PTFE covers most strong acids and bases. PFA handles similar chemistry at higher temperatures.

What temperature does each liner cover?
PTFE reaches 180°C, PFA reaches 200°C, and FEP reaches 150°C. All three start at -29°C.

How is the flange sealed?
A gasket sits between the valve flange and pipe flange. The liner extends over the flange face, so the gasket contacts the liner.

Can the valve be automated later?
Yes. Manual handles and pneumatic actuators interchange on most lined valve bodies.

FVF Fluorine Lined Pneumatic Ball Valve

• FVF lined ball valve has very high chemical stability, and is applicable for any other strong corrosion media except for molten alkalie and fluorine;
• FVF lined ball valve with full-bore and floating-ball structure can close the valve within the whole pressure range ensuring zero leakage, which facilitates the pipeline pigging and pipeline maintenance in the system;
• The integration of closure ball body and valve stem eliminates the possibility that the stem rushes out from pressure-containing parts due to pressure change, which ensures fundamentally the operational safety of the engineering;
• Reasonable and compact structure and minimum cavity of valve body reduce the sediment of the medium, in addition, special molding process, contributing to excellent airtight sealing surface, enables the valve to be zero leaked by combining with herringbone and annular PTFE packing;