Patent ID: 7384010

Claim:
A method for producing a crushed product, comprising the steps of: defining a crushing space in between crushing faces of a pair of confronting crusher discs; forming a rough crushing space for roughly crushing raw materials into a roughly crushed product in the crushing space by providing a first set of grooves in the crushing faces of the crusher discs; forming a fine powder crushing space for finely crushing the roughly crushed product into micropowder in the crushing space by providing a second set of grooves, which are shallower than the first set of grooves, in communication with the first set of grooves, consist of thin arcuate grooves formed in a dense arrangement on the crusher discs to coincide with a flow line of the micropowder and extend continuously from an inner side to an outer side of the crushing faces of the crusher discs in the crushing faces of the crusher discs; rotating one of said confronting crusher discs by a driving means; cooling the crusher discs through a cooling section; supplying one or more raw materials to the crushing space from a raw material supply site; supplying a cooled inert gas to the crushing space; effecting crushing of the raw materials under cooling thereof while replacing ambient oxygen on and around the raw materials by the inert gas; and bringing out the resulting crushed product from the crushing space to a crushed product delivery site.