Valve body: Typically made of cast steel, stainless steel, or ductile iron, with standard flange connections at both ends for easy pipe connection.
Disc: A retractable, round or conical component that seals via gravity or spring force. The material must be compatible with the media (e.g., stainless steel, rubber lining, etc.).
Valve seat: Fixed within the valve body, it forms a sealing surface with the disc and must be made of a wear- and corrosion-resistant material.
Guide: Guides the disc vertically, preventing it from drifting and ensuring a reliable seal.
Spring (optional): Some models feature a spring to assist in the rapid closing of the disc and reduce water hammer.
Operating Principle
Forward flow: Media pressure pushes the disc upward, clearing the seat, opening the valve and allowing media to flow smoothly.
Reverse Flow: When the medium pressure decreases or reverses, the disc rapidly descends under the force of gravity (or spring force), pressing against the valve seat and preventing backflow.
Core Features
Excellent Sealing: The disc and seat maintain perpendicular contact, ensuring uniform pressure on the sealing surface and low leakage.
Low Flow Resistance: The flow path is well designed, resulting in lower pressure loss than a swing check valve.
Fixed Installation: The disc must be installed vertically (the disc's lifting direction aligns with the direction of gravity) to ensure the disc can fall freely.
Widely Applicable Media: Suitable for water, steam, oil, gas, and other products, but the material should be selected based on the media's characteristics (e.g., corrosion resistance and high-temperature resistance).
Easy Maintenance: The flange connection allows for easy disassembly, allowing for online replacement of the disc or seal.
Application Scenarios
Pump Outlet: Prevents backflow of media during pump shutdown, protecting the pump body.
Boiler Feedwater System: Ensures one-way water supply to steam boilers, preventing water hammer damage to equipment.
Chemical Pipeline: Prevents backflow of corrosive media, ensuring process safety.
High-rise building water supply: Maintain stable water pressure and prevent backflow and contamination.
Fire protection systems: Ensure unidirectional flow of fire protection water to prevent system failure.
Selection Considerations
Nominal Pressure and Temperature: Select a valve rating (e.g., PN16, PN25, etc.) based on the system's operating pressure and temperature.
Diameter Matching: The valve diameter should match the pipe diameter to avoid abnormal flow rates.
Media Characteristics:
Corrosive media: Select valves with stainless steel or anti-corrosion material linings.
Media containing particles: Avoid using hard seals; rubber or soft-seal discs may be used.
Installation Orientation: Must be installed vertically to ensure the disc can fall freely.
Water Hammer Protection: If the system is prone to water hammer, a spring-assisted closing or slow-closing check valve may be used.
Standard Certification: Valves that comply with ISO, API, GB, and other standards are preferred to ensure reliable quality.
