Ptfe-lined Swing Check Valve Design And Application

For chemical processing, specify PTFE lined swing check valves (DN25–DN350, flanged, PN10/PN16/150LBS) to prevent backflow of corrosive media. Install in horizontal piping with flow direction matching body arrow. 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). These valves operate automatically — forward flow lifts the disc; backflow closes it against the seat. Flanged connections follow EN or ASME standards.

Corrosive Media Backflow Risks

Backflow of corrosive fluids causes pump impeller reversal, leading to mechanical damage. Reverse flow dilutes or contaminates process streams. Unlined check valves fail rapidly in acid or caustic service.

Key threats addressed:

• Pump damage – reverse rotation due to backflow.

• Product contamination – mixing of incompatible streams.

• Leakage – seal degradation from chemical attack.

• Safety – toxic fluid release from failed valves.

The ptfe lined check valve provides resistance to strong acids and alkalis. The fluoropolymer liner prevents direct metal contact with corrosive fluids.

Lined Swing Check Valve Design

The swing check valve features a hinged disc that swings away from the seat during forward flow. When flow stops or reverses, the disc returns to the seat, creating a seal. The PTFE lining covers all wetted surfaces — body, disc, and seat. Flanged connections (PN10, PN16, or 150LBS) enable direct installation into standard piping systems.

Key specifications:

• Body materials: WCB or CF8/CF8M with PTFE/PFA/FEP lining

• Size range: DN25 to DN350

• Pressure ratings: PN10, PN16, Class 150

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

• Connections: Flanged (EN, ASME, JIS)

The ptfe lined ball check valve variant uses a PTFE ball that rolls into the seat when flow stops. This design suits vertical piping with upward flow. The ball rotates during operation, providing a self-cleaning effect.

Lining Material Selection

Selection depends on operating 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.

Comparison of Lined Check Valve Types

The ptfe lined check valves are available in all three configurations. The ptfe check valve remains the standard choice for general corrosive service.

Chemical Industry Applications

Lined swing check valves are installed in piping systems handling aggressive media.

Typical applications:

• Acid and caustic transfer lines

• Solvent and chemical feed systems

• Chlor-alkali process plants

• Fertilizer production

• Pharmaceutical intermediate transfer

The valves comply with HG/T 3704 and ASME B16.34 design standards. Flange connections follow EN 1092-1 or ASME B16.5.

Installation and Maintenance

Installation requires aligning flanges with gaskets. The valve body arrow must match flow direction. Horizontal piping is required for swing check valves; vertical installation prevents disc operation.

Maintenance points:

1. Inspect lining for cracks or deformation.

2. Check disc movement for free swing action.

3. Verify flange bolt torque annually.

4. Replace seat or disc if leakage occurs.

Lined valves offer service life with reduced maintenance requirements. The ptfe lined check valve remains the standard choice for chemical applications where corrosion resistance is required. Specify lining material based on process temperature and chemical exposure to ensure reliable performance.

FVF PTFE Lined Swing Check Valve

• FVF lined swing check valve has a disc that rotates or swings in the direction of fluid flow. The disc can swing back against its seat to prevent the flow backwards .
• Its shaft and disc are designed as a whole, the lined shaft is embedded in the special groove which is formed between the valve body and the bonnet, making the opening and closing flexible and sealing reliable.
• FVF lined swing check valve is mainly used in chemical industries,such as sulfuric acid, alkali etc.

Product Parameter

Materials of Main Parts

Technical Specification