Fep Lined Gate Valve Design And Installation

For chemical processing, specify lined gate valves (flanged, DN15-DN350, PN10/PN16/150LBS, handwheel) for on/off service in corrosive media. Full FEP/PTFE/PFA lining isolates the metal body from strong acids and caustics. Select lining material based on temperature: FEP (-29°C to 150°C), PTFE (-29°C to 180°C), or PFA (-29°C to 200°C). Install in chemical transfer lines and acid handling systems. The handwheel enables manual operation. This design prevents corrosion, leakage, and metal ion contamination.

Corrosive Media On/Off Service Challenges

Strong acids and caustics corrode standard gate valves. Pitting and crevice corrosion develop in unprotected metal bodies. Unlined valves fail in aggressive chemical service. The fluoropolymer liner provides a barrier between fluid and metal parts.

Key threats addressed:

• Corrosion – chemical attack on metal wetted parts.

• Leakage – seal degradation from chemical exposure.

• Contamination – metal ions leaching into product streams.

• Safety – toxic fluid release from failed valves.

The teflon lined gate valve provides resistance to strong acids and oxidizers. The liner prevents direct metal contact with corrosive fluids.

Design and Specifications

The gate valve features a wedge-shaped disc that moves vertically to open or close the flow path. The lining covers all wetted surfaces, including body, bonnet interior, and gate. Flanged connections (EN, ASME) enable direct installation into standard piping systems. The handwheel mechanism allows manual operation.

Key specifications:

• Body material: WCB or CF8/CF8M with fluoropolymer lining

• Lining options: PTFE, PFA, or FEP

• Connection: Flanged (EN 1092-1, ASME B16.5)

• Sizes: DN15 to DN350

• Pressure: PN10, PN16, Class 150

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

The elastic gate compensates for sealing surface deviations, providing shut-off. The design meets HG/T 3704 and JB/T 11488 standards. Lining thickness is typically 3-4mm for corrosion resistance.

Lining Material Selection

Selection depends on operating temperature and chemical exposure.

FEP suits most chemical services including strong acids (hydrochloric, sulfuric, hydrofluoric). PTFE offers higher temperature rating for moderate chemical exposure. PFA provides highest temperature and permeation resistance for demanding applications.

Applications in Chemical Processing

Lined gate valves are installed in chemical plants, petrochemical refineries, and pharmaceutical manufacturing.

Typical applications:

• Acid and caustic transfer lines

• Chlor-alkali process plants

• Solvent and chemical feed systems

• Fertilizer production

• Pharmaceutical intermediate transfer

These valves are used for on/off service. They are not recommended for throttling applications as the gate may be eroded by high-velocity media.

Installation and Operation

Installation requires aligning flanges with appropriate gaskets. The valve should be installed with handwheel accessible. Proper support prevents pipe stress.

Installation points:

1. Align flanges with proper gaskets.

2. Tighten bolts evenly to specified torque.

3. Check handwheel operation for smooth movement.

4. Verify seal integrity after installation.

Operate the gate valve fully open or fully closed. Partial opening causes vibration and damage. The valve is bidirectional, allowing flow from either direction. PTFE packing (F4) provides stem sealing performance.

Why Specify Lined Gate Valves

1. Provides on/off service in corrosive media.

2. Offers flanged connections for permanent installation.

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

4. Resists strong acids, caustics, and solvents.

5. Enables manual operation with handwheel.

The lined gate valve is a solution for chemical processing requiring on/off flow control in corrosive service. The teflon lined gate valve design provides shut-off with low maintenance. Specify lining material (PTFE, PFA, or FEP) based on process temperature and chemical exposure to ensure reliable performance. The design meets HG/T 3704 and JB/T 11488 standards.

FVF FEP Lined Gate Valve

• FVF gate valve can be divided into rising stem gate valve, which refers to the disc doing lift movement in straight line along with the valve stem, and nonrising stem gate valve which refers to the stem nut located in the disc, when the stem rotates, the disc doing lift movement in straight line.
• The inner cavity of the valve body and bonnet, the gate, the outer surface of the valve stem and other components that directly contact the medium are all lined with FEP (F46) or PCTFE (F3) and other fluorine materials.
• The sealing pair are FEP (F46)/ FEP (F46) or combination of other materials, with small friction coefficient and low opening and closing torque.PTFE (F4) is used as the packing, which feactures good sealing performance and convenient maintenance and replacement.
• FVF lined gate valves are commonly used in chemical, petroleum, pharmaceutical, food, metallurgy, paper, hydropower, environment protection etc.

Product Parameter

Materials of Main Parts

Technical Specification