Double shaft paddle mixer and arrangement and methods for producing paste

A double shaft paddle mixer, comprising:

• a barrel chamber that is elongated and that extends axially;
• a first paddle screw and a second paddle screw configured to rotate together in the barrel chamber in an intermeshing relationship,
• the first paddle screw being provided with first paddles extending from a first shaft and the second paddle screw being provided with second paddles extending from a second shaft,
• the barrel chamber comprising a crushing zone and a mixing zone,
• the crushing zone being partly separated from the mixing zone by a partition member,
• a first inlet connected to an upstream region of the crushing zone,
• a second inlet being connected to an upstream region of the mixing zone and an outlet connected to a downstream region of the mixing zone, and
• wherein the average paddle angle of the first paddles with respect to the centerline of the first paddle screw and the second paddles with respect to the centerline of the second paddle screw is larger in the mixing zone than in the crushing zone,
• wherein the partition member extends from an inner surface of the barrel chamber,
• wherein a limited passage is provided at the partition member between the crushing zone of the barrel chamber and the mixing zone of the barrel chamber essentially correspond to the cross section of the shape the first paddle screw and the second paddle screw together form as they rotates in the barrel chamber, and
• wherein the relative number of first paddles and second paddles as calculated along a first rotation axis of the first paddle screw and as calculated along a second rotation axis of the second paddle screw is larger in the crushing zone than in the mixing zone.