The working principle of the micro-resistance slow-closing butterfly check valve
The micro-resistance slow-closing butterfly check valve mainly consists of a valve body, two semi-circular valve discs, a return spring, an oil storage cylinder, a slow-closing small cylinder assembly, and a needle valve (for fine adjustment). Its principle relies on the thrust of the incoming medium to smoothly push open the two valve discs. At the same time, the pressurized medium from the inlet enters the lower part of the piston in the oil cylinder, pushing the piston upward. This causes the oil above the piston to be forced through the needle valve into the ends of the small cylinders on both sides of the valve body, causing the piston rods inside the small cylinders to extend. When the pressure of the incoming medium drops below that of the outlet, the medium begins to flow back. Under the action of the spring and the returning medium, the valve discs automatically close. However, since the piston rod is in an extended position, it prevents the valve discs from closing completely, allowing about 20% of the area to remain open for the medium to pass through. This helps to eliminate water hammer effects. The valve discs are closed in two stages: first quickly, then slowly, which not only prevents the motor from reversing but also helps to reduce noise.

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