DN80 Sealing oil vacuum tank floating valve

DN80 floating valve comprises the floating ball, drive part, and regulating plug controlled by the needle plug for hydraulic amplification. The piston uses differential pressure system, and the sealing surface of the upper area is larger than that of the area below. The pressure oil from the source for the oil-supply enters the middle cavity of the piston then goes into the upper cavity of the piston. A vent in the middle of the piston controlled by the needle plug is connected with the oil tank. When the liquid level of the oil tank is normal, the buoyancy of the floating ball is transferred through the lever and increases, in order to make the conical head of the needle plug pressed tightly on the vent in the middle of the piston. For the pressure caused by pressure oil source to enter the upper cavity of the piston the upper area of the piston is bigger than the seal-oil area below. The operating piston moves downward and is pressed tightly on the sealing surface. The valve is kept closed.
The buoyancy of the floating ball decreases along with the liquid-level of the oil tank drops. When the rightward force is larger than the leftward force caused by the buoyancy of the loating ball, the needle plug moves to the right and the central vent of the piston is opened. The pressure oil in the upper cavity of the piston is drained to the vacuum oil tank, and the oil in the middle cavity of the piston pushes the piston to the right and opens the valve to supply the oil for the oil tank. When the liquid-level rises to a certain position, the buoyancy of the floating ball increases and the needle point of the valve is pressed tightly on the center hole. The upper cavity of piston is connected with the pressure oil source. The valve is closed and oil-supply is completed. The process of the oil-supply goes along with the change of the liquid-level slowly. The needle plug and the piston move simultaneously. The operating principle is the same as the oil-drain valve so as to control the liquid-level of the oil tank.