Abstract: An internal batch mixing machine includes a mixing chamber having a pair of cavities in which a first and a second rotor are mounted adjacent one another and are driven in opposite directions to mix material. The circumference of each rotor is divided into first, second, third and fourth sequential quadrants spaced in a direction opposite to the intended direction of rotation of that rotor. Each of the rotors has preferably a pair of lobes or wings located in every other quadrant of that rotor, although three lobe rotors are possible. Each lobe has a leading end and a trailing end. The first rotor has a pair of lobes located in its first and third quadrants, while the second rotor has a pair of lobes located in its second and fourth quadrants. One of the lobes of each pair of lobes is longer than the other, and each lobe extends downstream at an acute cohelix angle toward the other lobe of its pair.

Abstract: A valve is disclosed having a generally cylindrical body having an inlet and an outlet opening and a lateral opening. The valve body is received in a cylindrical collar which is heat shrunk onto the cylindrical body of the valve to provide a prestressed condition in the valve body thereby substantially increasing the strength of the body.