Design And Application Of Semi-lined Ptfe Worm Gear Wafer Butterfly Valve

For chemical processing, specify PTFE lined butterfly valves (wafer, worm gear, DN50-DN600, PN10/PN16/150LBS) for corrosive media control. The PTFE liner isolates the metal body from acids and caustics. Select lining material based on temperature: PTFE (-29°C to 180°C), PFA (-29°C to 200°C), or FEP (-29°C to 150°C). Gaskets match the lining material (PTFE, PFA, or FEP). Install wafer-style between flanges. Use worm gear actuation for large sizes. This design prevents corrosion, leakage, and fugitive emissions.

Corrosive Media Pipeline Threats

Acids, caustics, and solvents attack unprotected metal surfaces. Pitting and crevice corrosion develop in valves without linings. Standard butterfly valves fail rapidly in chemical service.

Key threats addressed:

•  Corrosion – chemical attack on metal wetted parts.

•  Leakage – seal degradation from chemical exposure.

•  Safety – toxic fluid release from failed valves.

•  Shutdown – unplanned maintenance due to failure.

The ptfe lined butterfly valve provides resistance to strong acids and oxidizers. The liner creates a barrier between fluid and metal body.

Design and Specifications

The butterfly valve features a disc that rotates within the bore to control flow. The PTFE lining covers all wetted surfaces, including disc and body interior. Wafer connection (between flanges) saves space and reduces weight. Worm gear actuation provides mechanical advantage for larger valves (DN50-DN600). Gaskets are manufactured from the same material as the lining (PTFE, PFA, or FEP) to ensure seal compatibility.

Key specifications:

• Body material: Ductile iron (GGG40) or stainless steel

• Lining: PTFE, PFA, or FEP

• Gaskets: PTFE, PFA, or FEP

• Connection: Wafer (between flanges)

• Actuation: Worm gear (manual)

• Sizes: DN50 to DN600

• Pressure: PN10, PN16, Class 150

• Temperature: PTFE (-29°C to 180°C), PFA (-29°C to 200°C), FEP (-29°C to 150°C)

The ptfe butterfly valve design provides bubble-tight shut-off. The worm gear reduces operator effort for larger sizes.

Applications in Chemical Processing

PTFE lined butterfly valves are installed in chemical plants, petrochemical refineries, and waste treatment facilities.

Typical service conditions:

• Media: hydrochloric acid, sulfuric acid, caustic soda, organic solvents

• Temperature: -29°C to 180°C (PTFE)

• Pressure: PN10, PN16, Class 150

• Sizes: DN50 to DN600

The ptfe lined valves are specified for services where corrosion resistance is required. The wafer design enables installation between existing flanges without additional pipe supports.

Lining Material Selection

Selection depends on temperature and chemical exposure.

PTFE suits most chemical services. PFA offers higher temperature rating for aggressive media. FEP provides a cost-effective alternative for less demanding applications.

Installation and Operation

Installation requires centering the valve between flanges with appropriate gaskets (PTFE, PFA, or FEP). Flange bolts should be tightened evenly to specified torque. Worm gear allows locking at any position.

Installation points:

1. Center valve between flanges.

2. Use gaskets matching lining material (PTFE, PFA, or FEP).

3. Tighten bolts evenly to specified torque.

4. Check operation after installation.

The ptfe lined butterfly valves require no lubrication of the liner. The worm gear box requires periodic lubrication. The valve operates with low torque.

Why Specify PTFE Lined Butterfly Valves

1. Provides bubble-tight shut-off in corrosive service.

2. Offers wafer connection for compact installation.

3. Supports temperatures from -29°C to 200°C with appropriate lining.

4. Reduces fugitive emissions with robust sealing.

5. Enables manual operation with worm gear.

The PTFE lined butterfly valve is a solution for chemical processing requiring reliable flow control in corrosive media. The ptfe lined valves design provides service life with reduced maintenance. The ptfe lined butterfly valves are standard for chemical applications where metal valves fail.

FVF Half PTFE Lined Wafer Type Butterfly Valve With Worm Gear

• 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.