Breakable blind plate type floating coupling device, using method and preparation method of blind plate

The invention provides a breakable blind plate type floating coupling device, a using method and a preparation method of a blind plate. The breakable blind plate type floating coupling device comprises an upper joint and a lower joint which are arranged up and down and are screwed, wherein an annular groove is formed in the inner wall of the upper joint; a breakable blind plate, a limiting ring and an impactor ring are sequentially embedded in the annular groove from top to bottom; the lower end surface of the breakable blind plate is tightly attached to the upper end surface of the limiting ring; a gap is reserved between the lower end surface of the limiting ring and the upper end surface of the impactor ring; and a plurality of impactors capable of penetrating through the limiting ringto impact the breakable blind plate are inserted into the ring surface of the impactor ring. The breakable blind plate is broken into powder under the impact of the impactors, the breaking effect is good, a circulating channe