PURPOSE: To contrive automatically discharging treatment of the substance to be separated by constituting the centrifugal separator so that it has a centrally concentrated discharge structure and a ringlike stop valve made of a thin plate is fitted to a reverse conical cylinder 12 for the O-ringlike valve seat of the upper conical cylinder and also equipped with a nontouchably and automatically opening/closing and operating function due to hydraulic pressure or the like.

CONSTITUTION: The centrifugal separator is constituted so that it has a centrally concentrated discharge structure and a ringlike stop valve 11 made of a thin plate is fitted to a reverse conical cylinder 12 for the O-ringlike valve seat 7 of the upper conical cylinder 8 and also equipped with a nontouchably and automatically opening/closing and operating function due to hydraulic pressure and magnetic force or the like. As a result, the automatically discharging treatment of the substance to be separated is enabled in the cylindrical centrifugal separator.