Butterfly microresistance slow closing check valve

The utility model relates to a butterfly microresistance slow closing check valve which comprises a valve body, a valve clack and a valve shaft. An inclined angle of 12-20 degrees is formed between the valve seat sealing surface and the centerline of a valve body channel, the valve shaft is located at a position which is one quarters of the upper portion of the minimum diameter of the valve seat sealing surface inside the valve body, the valve shaft is perpendicular to the centerline of the valve body channel, a piston is positioned inside a cylinder below a valve seat inlet flange, one end of a piston rod is fixedly connected with the piston, and the other end of the piston rod is stretched into an inner cavity of the valve body and form an inclined angle of 30-38 degrees together with the centerline of the valve body channel. A non-rod cavity of the piston is communicated with a valve cavity of the outlet of the valve seat sealing surface through a mini-adjustable valve, a valve cavity of the inlet of the valve seat sealing surface is communicated with the non-rod cavity of the piston through a one-way valve, the back of the valve clack is connected with a baffle which abuts against the end portion of the piston rod to prevent the valve clack from being closed rapidly, and media are prevented from flowing back and producing water hammer. The butterfly microresistance slow closing check valve has the advantages of being good in slow closing performance, small in starting resistance, good in sealing performance, small in size, light in weight and the like. The butterfly microresistance slow closing check valve is suitable for outlets of water turbines and water pumps to protect equipment safety.