A mixer includes: a casing having an introduction port at an upper portion and having a rotor provided with a blade portion for mixing a material to be mixed, inside thereof; a floating weight which blocks the introduction port; and a floating weight moving mechanism which has a horizontal movement unit capable of horizontally moving the floating weight in a supported state between a delivery position just above the introduction port and a retracted position being lateral to the introduction port, on the upper side of the introduction port, and can move the floating weight separately from the horizontal movement unit from the delivery position to a blocking position at which the floating weight blocks the introduction port.

The internal batch mixer with three-wing non-intermeshing rotors includes a pair of non-intermeshing, counter-rotating, tangential rotors each having three wing portions. The internal batch mixer includes a housing defining a mixing chamber, where the mixing chamber includes first and second substantially circular chamber cavities in open communication with one another at a central region of the mixing chamber. The first and second non-intermeshing, counter-rotating winged rotors are respectively rotationally mounted within the first and second substantially circular chamber cavities, such that the central region of the mixing chamber defines an interacting mixing region between the first and second non-intermeshing, counter-rotating winged rotors. The first and second non-intermeshing, counter-rotating winged rotors are driven to counter-rotate with respect to one another. Each rotor has a substantially helical contour and a blade portion divided into three separate wings.

A polymer processing system includes a mixer. The mixer includes at least one side wall and a bottom wall that cooperate to define a chamber. At least one side wall also defines a bore. The mixer also includes a pair of rotors that are disposed in the chamber and are rotatably received by the at least one side wall for mixing polymers. The mixer also includes at least one injector that at least partially extends through the bore of the at least one side wall. The polymer processing system also includes a ram that is movably connected to the mixer. The polymer processing system also includes a compressed air supply that is fluidly connected to the at least one injector to supply compressed air to the chamber through the at least one injector.