The valve seat structure pre-loaded by cyinder spring and with compensation movable metal materials is adopted to realize reliable sealing perfomance. The valve core- -valve seat do not suffer from blockage or disconnection; they enjoy a long use life. V-shaped notch in the valve core and the metal valve seat have a shearing role; they are particularly applicable to the medium with high viscosity, with fiber, to the solid particle and sury. The pulp of structural paper manufacturing industry od obviously superior. The valve is featured as large flow, small pressure loss and no medium sedimentation in the middle cavity of the valve. The valve not only enjoys flow features similar to percentage and large adjustment scope (maximum adjustment ratio is 100: 1), but also enjoys accurate adjustment and reliable positioning functions. Numerous driving units can be cllocated for the valve series.