Material And Design Features Of Worm Gear Operated Ptfe/pfa Lined Butterfly Valves

To prevent corrosive leaks, install a worm gear operated lined butterfly valve with PTFE or PFA lining and wafer connection. Select lining based on temperature (PTFE: -29°C to 180°C; PFA: -29°C to 200°C; FEP: -29°C to 150°C). Choose pressure rating PN10, PN16, or 150LBS. The fluoropolymer lining isolates fluid from metal parts, eliminating pitting and pinhole leaks. This valve provides bubble-tight shut-off, handles sizes DN40-DN600, and the worm gear actuator enables precise throttling with self-locking action.

The Corrosion Leak Threat

Corrosive fluids—acids, caustics, solvents—attack unprotected metal internals. Pitting, crevice corrosion, and stress cracking lead to wall penetration and sudden leaks. A leaking valve releases toxic media, causes shutdowns, and endangers personnel. A lined butterfly valve with PTFE or PFA lining stops corrosion at the source.

Failure modes eliminated:

•  Pitting from chloride attack

•  Crevice corrosion under seals

•  Stress cracking from thermal cycling

•  Erosion from abrasive particulates

•  Permeation through metal walls

Wafer Connection and Pressure Ratings

The valve uses wafer connection between flanges, fitting PN10, PN16, and 150LBS systems. Compact and lightweight, it suits raised face and flat face flanges. Centering lugs ensure proper alignment. This configuration reduces weight and cost while maintaining sealing integrity.

Lining Material Selection

PTFE and PFA Lined Configurations

The ptfe lined butterfly valve offers resistance to most acids, bases, and solvents from -29°C to 180°C. The ptfe butterfly valve provides a non-stick surface that prevents media adhesion and eases cleaning. For high-temperature service, pfa lined butterfly valves handle up to 200°C with lower permeation. The pfa butterfly valve is specified for aggressive media requiring ultra-low extractables. Gasket materials (PTFE, PFA, FEP) match the lining and process requirements.

Key design features:

1. One-piece investment cast body minimizes leak paths

2. Separate lined disc and body ensure independent sealing

3. Thick lining (2-3 mm) resists erosion

4. Splined shaft prevents disc slippage

5. ISO 5211 mounting pad for actuator

Applications and Selection Considerations

1. The lined butterfly valve is used in acid transfer lines (sulfuric, hydrochloric, nitric), caustic service (sodium hydroxide), solvent handling (toluene, xylene, ketones), brine systems, and slurry pipelines.

2. When selecting, evaluate media type, pressure (PN10, PN16, or 150LBS), temperature range, and flow control accuracy. For most acidic lines, a ptfe lined butterfly valve provides an effective solution.

3. For high-temperature or permeation-sensitive services, pfa lined butterfly valves are preferred due to their higher temperature rating and lower permeation.

4. The worm gear actuator is recommended for valves larger than DN150 or where precise throttling control is required. Standard sizes cover DN40-DN600 with wafer or lugged connections.

Installation and Maintenance

Install between flanges per torque specs. Use gaskets matched to media and temperature. Align disc carefully to prevent binding. Avoid over-torquing flange bolts. The valve supports in-line inspection. Lubricate worm gear annually. Replace lining and seals every 3-5 years depending on service.

This valve design protects personnel and assets in chemical and petrochemical facilities where unprotected metal valves pose a continuous corrosion risk.

FVF Worm Gear Operated PTFE/PFA Lined Butterfly Valve

• FVF lined butterfly valve features a state-of-the-art design that provides excellent shutoff protection (bubble-tight shutoff) and high Cv values with exceptionally long service life. The resilient seated butterfly valve is available in a variety of materials including PTFE, PFA, Stainless Steel and special alloys to fit a wide range of customer requirements.
• FVF lined butterfly valves 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.
• FVF lined butterfly valves bi-directional flow is possible at maxmium operating 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.