Check valve issue
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Has anyone seen a check valve equipped with a hydraulic rotary cylinder and a weight? What is its working principle? In the past, they were all of straight-stroke type. Never seen one rotating
This check valve is automatically controlled in coordination with the start and stop of the water pump. When the pump stops, the solenoid valve in the hydraulic return line opens, allowing the weight to fall due to its own gravity; as a result, the pressurized oil in the cylinder flows back into the tank, and the valve closes accordingly.
Check Baidu for images of \"progressive check valves\" and you’ll understand right away.
This check valve functions somewhat like a shut-off valve; it does not require any pneumatic or electrical signals, and operates based on the pressure difference before and after the valve. It is found in fire protection systems and is used at the outlet of the main fire pump. Normally, the valve at the outlet of the main pump is open; this valve provides good sealing. Under normal conditions, the small pump is used to maintain pressure, and when needed, the main pump starts automatically. Once a certain pressure is reached, the check valve opens.
Both the cylinder and the weight serve as dampers, functioning to slow down the closing process and prevent the valve disc from hitting the valve seat and damaging the sealing surface
Hydraulic cylinders use back pressure to facilitate slow closing, while weights rely on their mass to reduce speed; according to the law of conservation of energy, the energy of water hammer drives the valve disc to close, as expressed by 0.5*mv2 – increasing the weight reduces the speed.