What is a check valve? PTFE Check Valve
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Author:Hualinkena
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Published time: 9 days ago
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A check valve is a valve that only allows the medium (liquid or gas) to flow in one direction and prevents backflow. Its core function is to enable unidirectional flow through internal structures (e.g., valve core, spring), and it is widely used in fluid conveying systems to prevent damage, process abnormalities, or energy loss caused by reverse flow (e.g., check valves at pump outlets).
A check valve is a valve that only allows the medium (liquid or gas) to flow in one direction and prevents backflow. Its core function is to enable unidirectional flow through internal structures (e.g., valve core, spring), and it is widely used in fluid conveying systems to prevent damage, process abnormalities, or energy loss caused by reverse flow (e.g., check valves at pump outlets).Features and Principle of PTFE Check Valves
PTFE (polytetrafluoroethylene, commonly known as "Teflon") is a high-performance engineering plastic. It is used to manufacture key components of check valves (such as valve seats, valve cores, seals, or full valve bodies) due to its unique physicochemical properties. Below is an explanation from three aspects: material properties, structure and working principle, and application scenarios.
1. Core Properties of PTFE Material
The properties of PTFE directly define its advantages in check valve applications:
Superior corrosion resistance: It hardly reacts with any acids, alkalis, or organic solvents (except molten alkali metals and fluorine elements), making it ideal for highly corrosive media (e.g., hydrochloric acid, sulfuric acid, aqua regia, chlorine).
High-temperature resistance: With a long-term operating temperature range of -200°C to 260°C and short-term tolerance up to 300°C, it adapts to extreme thermal environments.
Low friction coefficient: With a smooth surface (friction coefficient ≈ 0.04), it minimizes flow resistance for media, reduces scaling/adhesion, and lowers blockage risks.
Non-stick property: Media rarely adhere to the valve’s inner walls, simplifying cleaning and meeting food/pharmaceutical hygiene standards.
Chemical stability: No leachable substances are released, preventing medium contamination—critical for high-purity fluids (e.g., semiconductor cleaning solutions, injection water).
2. Structure and Working Principle of PTFE Check Valves
The structure of a PTFE check valve is similar to conventional ones but optimized for PTFE’s material characteristics:
Key components: Typically includes a PTFE valve seat (fixed sealing surface), PTFE valve core (e.g., ball, swing, or lift type), an optional spring (aids closing), and a valve body (either metal-clad PTFE or all-PTFE).
Working process: When medium flows forward, pressure pushes the valve core away from the seat, opening the valve. For reverse flow, backpressure forces the core to press tightly against the PTFE seat, closing the valve and blocking backflow.
Key improvements: PTFE’s low friction ensures flexible core movement (reducing jams). Though less elastic than metal, its deformation capacity can be compensated via structural design (e.g., thin-walled seats) to guarantee zero leakage.
