Views: 0 Author: J-VALVES Publish Time: 2025-06-10 Origin: Site
Understanding Swing Check Valves
Swing check valves operate by allowing fluid to flow freely in one direction while automatically closing to prevent backflow when the flow direction reverses. The valve's disc swings on a hinge or trunnion, aligning with the flow direction when open and sealing against a seat when closed.
Key Components of Swing Check Valves
• Valve Body: The main structure that houses all internal components.
• Disc: The movable component that swings to allow or block flow.
• Seat: The surface against which the disc seals to prevent backflow.
• Hinge or Trunnion: The mechanism that allows the disc to swing.
• Bonnet: The cover that protects the internal components and provides access for maintenance.
Key Parameters for Sizing and Pressure Rating Selection
The nominal diameter (DN) is the primary parameter for sizing a swing check valve. It determines the valve's flow capacity and must match the piping system's diameter to ensure proper flow and minimal pressure drop.
• Flow Capacity: Larger diameters allow higher flow rates but may increase pressure drop if not properly designed.
• System Compatibility: Ensure the valve's DN matches the piping system to avoid unnecessary pressure losses and ensure smooth operation.
The pressure rating indicates the maximum pressure the valve can safely withstand at a specified temperature. Common pressure ratings include:
• Class 150 (PN16): Suitable for low-pressure applications.
• Class 300 (PN20): Ideal for moderate-pressure applications.
• Class 600 (PN40): Suitable for high-pressure applications.
• Class 900 (PN63): For very high-pressure applications.
• Class 1500 (PN100): For extremely high-pressure applications.
• Class 2500 (PN160): For ultra-high-pressure applications.
3. Flow Rate and Pressure Drop
The flow rate and pressure drop across the valve are critical parameters for ensuring system efficiency. The valve must be sized to handle the required flow rate while minimizing pressure drop.
• Flow Rate: Determine the required flow rate based on system demands.
• Pressure Drop: Calculate the expected pressure drop using the valve's Cv (flow coefficient) and ensure it aligns with system requirements.
The temperature range of the fluid affects the valve's material selection and pressure rating. Ensure the valve is designed to handle the operating temperature range to prevent material degradation and maintain performance.
The type of fluid and its characteristics (e.g., viscosity, corrosiveness) influence the valve's material and seal selection. Choose materials that are compatible with the fluid to ensure long-term reliability.
The installation orientation of the swing check valve affects its performance. Ensure the valve is installed in the correct orientation to allow proper disc movement and sealing.
