A fluoropolymer-lined check valve, also known as a non-return valve, is a type of valve that allows the medium to flow in only one direction while preventing flow in the opposite direction. These valves are typically automatic; under the pressure of the fluid flowing in one direction, the valve disc opens; when the fluid flows in the opposite direction, the fluid pressure and the weight of the valve disc combine to act on the valve seat, thus cutting off the flow.
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Fluorine-Lined Check Valve Technical parameters
Size Range: DN40–DN1200
Pressure Range: PN6–PN16
End Connection: Wafer, Lug, or Flanged
Material: Ductile Iron or Carbon Steel Body with PTFE/FEP Lining
Seals: PTFE/FEP
Valves Design: Centered or Eccentric Fluorine-Lined Butterfly Valve
Face to Face: ISO 5752 / API 609
End Connection: ASME B16.5, EN 1092-1
Testing & Inspection: API 598, ISO 5208
Suitable Medium: Acidic, Alkaline, and Corrosive Fluids
Fluorine-Lined Check Valve Working Principle
The fluoropolymer-lined check valve automatically opens and closes its valve disc based on changes in the direction of medium flow:
Forward flow: The medium pressure pushes the valve disc open, allowing fluid to pass through;
Reverse flow: The valve disc closes rapidly under its own weight and the reverse pressure of the medium, cutting off the fluid passage.
This process requires no external power; it is entirely driven by the kinetic energy of the medium, achieving automated backflow prevention control.
Fluorine-Lined Check Valve Structural Features
Fluoroplastic Lining: The valve body is lined with fluoroplastics such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or perfluoroalkoxy resin (PFA). These materials possess extremely strong chemical stability and can withstand most corrosive media except for molten alkali metals and elemental fluorine.
Diverse structural forms:
Lift type: The valve disc slides along the vertical centerline of the valve body, suitable for horizontal pipeline installation, with excellent sealing performance;
Swing type: The valve disc rotates around the inner pin of the valve seat, with a simple structure, suitable for horizontal pipelines;
Double-disc butterfly type: Adopts a short double-disc structure to reduce fluid resistance, improve opening response speed, and the clamp-on installation design shortens the flow path length and enhances media flow efficiency.
Fluorine-Lined Check Valve Performance Advantages
- Superior Corrosion Resistance: Fluoroplastic linings can withstand long-term corrosion from strong acids, alkalis, oxidants, and organic solvents, replacing rare metal materials and reducing equipment costs.
- Reliable Sealing Performance: Both the valve disc and seat sealing surfaces are lined with fluoroplastic layers. Combined with the continuous sealing pressure provided by the spring, reliable sealing is ensured even in low-pressure areas, reducing water hammer damage.
- Low Flow Resistance Design: Features such as the butterfly-type double-disc structure utilize a short valve disc, reducing fluid resistance and improving flow efficiency.
- Fast Response and Closure: The combination of spring-forced reset and a short-stroke design results in rapid closure, effectively mitigating water hammer pressure caused by reverse flow.
- Wide Operating Condition Adaptability: Operating temperature ranges typically from -50℃ to 150℃, and pressure environments cover atmospheric to high pressure environments, meeting diverse industrial needs.
Fluorine-Lined Check Valve Applications
PTFE-lined check valves are widely used in industrial applications requiring extremely high corrosion resistance of the media:
- Chemical Industry: Transporting strong acids such as sulfuric acid, hydrochloric acid, and hydrofluoric acid, as well as organic solvents;
- Petroleum Industry: Handling oil-gas mixtures containing corrosive components;
- Pharmaceutical Industry: Transporting pharmaceutical solutions and chemical reagents;
- Power Industry: Transporting cooling water, desulfurizing agents, and other media;
- Environmental Protection Industry: Treating corrosive fluids such as wastewater and sewage;
- Food Industry: Transporting acidic or alkaline food ingredients.
