Check Valve Placement and Coordination in Pipeline Systems
Mar 06, 2024
A check valve, also known as a non-return valve, holds significant importance within pipeline systems. Its primary function lies in utilizing the pressure of the flowing medium within the pipeline to automatically open and close the valve disc. Upon cessation of flow, the check valve's disc swiftly closes, effectively preventing any backflow within the pipeline, thus ensuring the safe operation of the entire system.
Determining the Installation Position
Selecting the appropriate installation position for a check valve entails careful consideration of whether to place it before or after a pump, as well as its compatibility with other valves.
1. Pre-Pump Installation: Typically positioned at the pump's inlet, this setup, also referred to as bottom valve installation, proves ideal when the liquid level is lower than the pump. Its purpose is to ensure that the pump can start without requiring an additional water supply, thereby preventing dry running.
2. Post-Pump Installation: In contrast, placing the check valve after the pump, at the outlet, is suitable for scenarios where the liquid level exceeds that of the pump. This configuration, particularly useful in booster pump systems, effectively prevents any potential backflow.
Coordinated Integration with Other Valves
Check valves often work in tandem with other valves such as gate valves, butterfly valves, and the like.
As a general rule, check valves should be positioned before the pump's outlet or preceding the outlet control valve for ease of maintenance. Typically, the pump outlet is connected via a flexible joint (shock absorber), followed by the check valve, and subsequently, isolation valves like butterfly valves, gate valves, globe valves, etc.
1. Check Valve Before
Advantages: This arrangement safeguards the integrity of the check valve, particularly in parallel pump systems. In such setups, if one pump remains inactive with its outlet valve closed, the impact force upon the activation of another pump is absorbed by the gate valve or butterfly valve. In case of check valve failure, the inlet and outlet valves can be shut to isolate the system for repair.
Disadvantages: While the gate valve or butterfly valve receives protection, the performance of the check valve may be compromised or it may even fail.
2. Gate Valve or Butterfly Valve Before
Advantages: This configuration shields the gate valve or butterfly valve, with the check valve absorbing any impact force.
Disadvantages: The check valve's operation is contingent upon pressure differentials. If the main pressure is high, it closes; if the pump pressure is high, it opens. In situations where flow rates fluctuate, the check valve may experience frequent cycling, thereby potentially diminishing its lifespan. Additionally, in the event of check valve malfunction, particularly within booster pump systems, system shutdown is necessary for repairs.
Advantages: This arrangement safeguards the integrity of the check valve, particularly in parallel pump systems. In such setups, if one pump remains inactive with its outlet valve closed, the impact force upon the activation of another pump is absorbed by the gate valve or butterfly valve. In case of check valve failure, the inlet and outlet valves can be shut to isolate the system for repair.
Disadvantages: While the gate valve or butterfly valve receives protection, the performance of the check valve may be compromised or it may even fail.
2. Gate Valve or Butterfly Valve Before
Advantages: This configuration shields the gate valve or butterfly valve, with the check valve absorbing any impact force.
Disadvantages: The check valve's operation is contingent upon pressure differentials. If the main pressure is high, it closes; if the pump pressure is high, it opens. In situations where flow rates fluctuate, the check valve may experience frequent cycling, thereby potentially diminishing its lifespan. Additionally, in the event of check valve malfunction, particularly within booster pump systems, system shutdown is necessary for repairs.
Additional Considerations
Given the repetitive opening and closing actions of check valves, the internal connections and sealing components are susceptible to wear. Therefore, prudent selection of the check valve's installation position and its coordination with other valves is essential to facilitate repairs and prevent system-wide shutdowns due to check valve failures.
In summary, careful consideration of the installation position of check valves and their coordinated operation with other valves is crucial in the design of pipeline systems. Proper installation and configuration play pivotal roles in ensuring the safe operation of pipeline systems and the optimal performance of equipment.
Next: Maintenance Guide for Pneumatic Ball Valve Seal Replacement
Previous: Trim Numbers of Valves
About Us
Categories
Useful Links
Our Contacts
Building 2, NO.59, Songshan Road, SND, Suzhou, China