Check valves are crucial components used to prevent unidirectional flow of fluids in pipelines, ensuring the safe operation of the pipes. However, improper use can lead to damage, potentially causing pipeline leaks or unstable fluid pressure, making correct usage of check valves vital.
Before using a check valve, it's essential to select the appropriate model based on the fluid medium to be handled and the operational parameters of the pipeline. Different types and sizes of check valves are suitable for various fluid mediums and pipeline systems, so careful selection is crucial.
Proper installation of check valves is a critical step in their use. During installation, follow the model and specifications of the check valve to ensure it is mounted in the correct position. For gravity check valves, ensure the drain is clear, and the valve bracket should be installed horizontally; vertical installation can cause the valve to close unevenly, affecting fluid release. For spring or pneumatic check valves, install the valve at the exact pipe location and pay attention to checking the operation of its actuator.
When using check valves, it is important to avoid sudden impacts. Sudden opening and closing can damage the valve, so operate the valve smoothly and avoid excessive force. After the valve is fully open, turn the handwheel slightly in the opposite direction to ensure a tight fit between the threads, preventing loosening and damage. For clear stem valves, remember the position of the valve stem when fully open and fully closed to avoid hitting the dead point when fully open. This also facilitates checking if it is closed properly. If the valve handle falls off or there is a large foreign object embedded between the valve core and the seal, the position of the valve stem when fully closed will change.
When operating check valves, pay attention to certain markings. For instance, when the slots and channels on the top of the ball, butterfly, and plug valve stems are parallel, it indicates that the valve is fully open. When the stem is rotated 90 degrees to the left or right, the slots and channels are perpendicular, indicating the valve is fully closed. The operation of three-way and four-way valves should be done according to the markings for opening, closing, and reversing. After operation, remove the movable handle.
In summary, the proper use of check valves is crucial for ensuring pipeline safety. When selecting and using check valves, it is essential to choose the appropriate valve model based on the fluid medium to be handled and the working parameters of the pipeline, and to install them according to the correct method. During operation, attention should be given to avoid impacts, operate the valve smoothly, and observe certain signs to ensure the normal operation of the check valve.
