Selection techniques, installation, debugging, and troubleshooting of double-disc check valves
Release time:
2024-10-14
A. Installation, Testing, and Adjustment:
a. Whether manually, pneumatically, hydraulically, or electrically operated, all components of this valve are strictly tested before leaving the factory. When re-checking the sealing performance, the user should fix both the inlet and outlet sides evenly, close the butterfly valve, apply pressure to the inlet side, and observe whether there is any leakage on the outlet side. Before conducting a pipeline strength test, the butterfly plate should be opened to prevent damage to the sealing pair.
b. Although the valve has undergone strict inspection and testing before leaving the factory, there is still a possibility that individual products may have automatic screw displacement during transportation and need to be re-adjusted (pneumatic, hydraulic, etc.). Please refer to the accompanying drive unit instruction manual.
B. Common Faults and Troubleshooting Methods:
a. Before installation, Confirm that the performance of this factory's product and the flow direction arrow of the medium match the operating conditions, and clean the valve cavity. No impurities or foreign objects are allowed on the sealing ring and butterfly plate. Do not close the butterfly plate before cleaning to avoid damaging the sealing ring.
b. For the installation of the double-flange butterfly plate, it is recommended to use a butterfly valve flange, namely the HGJ54-91 type socket welding steel flange.
c. The position of installation in the pipeline; *position is vertical installation, but cannot be inverted. Regularly inspect the valve's performance and promptly address any malfunctions.
d. When adjusting the flow rate during use, use the worm gear box for control.
e. Check that all connecting parts are tightened to ensure both the sealing of the packing and the flexible rotation of the valve stem.
Water hammer pressure surge issues exist during use. A design scheme to add a slow-closing auxiliary valve has been proposed. The improved product features smooth opening and closing, reducing the impact of water hammer pressure.
A check valve is a valve that opens when the fluid flows in the forward direction and closes when the fluid flows in the reverse direction in a pipeline system. It is mainly used to prevent backflow, prevent the pump and drive motor from reversing, and prevent the release of medium in the container. Currently, widely used are the swing check valve, where the valve flap rotates around the valve body pin, and the lift check valve, where the valve flap moves along the vertical center line of the valve body. However, both of these check valve structures have a problem: when closing, the backflow speed of the medium rapidly decreases from maximum to zero, causing the internal pressure on the inlet side of the pipeline to rise rapidly, thus producing a water hammer phenomenon that can damage the pipeline system. Therefore, the general check valve production diameter is 50～500 mm [1]. To reduce the water hammer effect of the check valve and expand its application range, an auxiliary slow-closing valve is added based on the original product, solving the problem of water hammer pressure surge in the pipeline.
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