Patent ID: 8911139

Claim:
An internal batch mixer, comprising: a mixing device for mixing material; and a display device provided outside said mixing device, wherein said mixing device includes: a casing in which the material is mixed and which has a material discharge opening formed to discharge the mixed material; a door which opens and closes said material discharge opening by rotating around a shaft, and blocks said material discharge opening when it is in a closed state; and a latch mechanism which holds, during mixing of the material within said casing, said door in a latched state, the latched state being a state in which said latch mechanism presses said door to said casing so that said door blocks said material discharge opening and cannot be opened, and which releases the latched state when discharging the material mixed within said casing out of said casing, said latch mechanism includes: a latch member provided to be contactable with said door; a linear actuator which has a linearly-movable moving part and which supplies power to said latch member to direct said latch member to said door side by moving said moving part toward said door; and a linear sensor which measures distance of linear movement of said moving part by said linear actuator, and said display device displays displacement information of said latch member based on the distance of linear movement of said moving part measured by said linear sensor, wherein the internal batch mixer further includes: a storage device which stores a set value relating to the displacement information of said latch member; and an alarm device which compares the displacement information of said latch member in the latched state with the set value, and gives an alarm when the displacement information of said latch member has reached the set value.