Structural classification of check valve
The check valve is a multi-function (slow closing) check valve with power unit and air travel coupler, and has electric/manual opening, closing and short-time throttling functions; The valve seat is inclined, all-metal sealing pair, butterfly plate double offset, overflow element with fluid guide and oil pressure slow closing device, which can be divided into two stages of fast/slow closing. It is a new multi-function waterproof hammer energy-saving product.
According to the structure, check valves can be divided into lift check valves, swing check valves and butterfly check valves. Lift check valves can be divided into vertical and horizontal types. Swing check valves are divided into three types: single-disc, double-disc and multi-disc. Butterfly check valve is straight-through type. The above check valves can be divided into threaded connection, flange connection and welding. The structure of the lift check valve is generally similar to that of the stop valve. The valve disc moves up and down along the line in the channel, which is reliable in action, but has large fluid resistance, and is suitable for light and small caliber situations. Lift check valve can be straight through and vertical. Straight-through lifting check valve can only be installed in horizontal pipeline, while vertical lifting check valve is generally installed in vertical pipeline. The disc of swing check valve rotates around the rotating shaft. Swing check valves can be divided into three types according to the number of valve discs: single-disc swing, double-disc swing and multi-disc swing. Single-disc swing check valve is generally suitable for medium caliber applications. When the single-disc swing check valve is selected for the large-diameter pipeline, the slow-closing check valve that can reduce the water hammer pressure is used to reduce the water hammer pressure. Double-disc swing check valve is applicable to large and medium diameter pipeline. Wafer double-disc swing check valve is a fast developing check valve with small structure and light weight; Multi-disc swing check valve is applicable to large-diameter pipeline. The structure of butterfly check valve is similar to that of butterfly valve. Its structure is simple, the flow resistance is small, and the water hammer pressure is also small.
The check valve can be widely used in petrochemical, metallurgical, electric power and urban water supply and drainage systems. When the pump starts or stops normally, it can also function as "outlet valve" and "check valve"; In case of sudden power loss of the pump and emergency shutdown of the pump, the valve can be closed automatically and orderly (fast/slow stages) to fully play the role of check valve, prevent water backflow, prevent the occurrence of destructive water hammer and ensure the safety of the pump station.