Patent ID: 7854542
Filing Date: 2010-12-21
Classification: B29B

Abstract:
1. A batch mixer, comprising: a case having a chamber for mixing therein; a pair of mixing rotors rotating in the opposite direction to each other, the pair of mixing rotors being in a non-intermeshing state; and a cooling structure for cooling down the inner surface of said chamber, wherein each of said pair of mixing rotors has a mixing section and comprises: a long wing that has an origin at one end portion of said mixing section and extends further than the center of said mixing section in the rotation axis direction of said mixing rotor so as to twist backward in the rotation direction of said mixing rotor, four or more of said long wings being disposed in the circumference direction of said mixing rotor; and a short wing that has an origin at the other end portion of said mixing section and extends to a position before the center of said mixing section in the rotation axis direction of said mixing rotor so as to twist backward in the rotation direction of said mixing rotor, four or more of said short wings being disposed in the circumference direction of said mixing rotor, wherein a narrow tip clearance and one or more of wider tip clearances are allowed to appear in the axis direction of the four or more of said long wings, a twist angle at the one end portion of the four or more of said long wings is 30° to 65°, the four or more of said long wings are formed in a twisted curve whose twist angle becomes smaller as it draws apart from the one end portion, the four or more of said short wings have a narrow clearance and one or more of wider clearances at least in the circumference direction in a mixed manner, and said long and short wings are disposed such that said narrow tip clearances pass for at least one time over the total length in the axis direction of said mixing section by the narrow tip clearance of said long wing and the narrow tip clearance of said short wing, when said mixing rotor is turned for one rotation, wherein the twist angle of the tip of said long wings that draw apart from the one end portion is 10° to 55°, and a twist angle at the other end portion of said short wings is 20° to 45° and is formed smaller than the twist angle of said long wings at the one end portion.