Separation device

1. A separation device comprising:

a first shredding unit that shreds a processing target containing a first material and a second material adhering to the first material;

a first separation unit that has a substantially cylindrical first tubular portion in which a large number of first holes that allow the second material contained in the processing target shredded by the first shredding unit to pass through without allowing the first material to pass through are formed, and that separates the second material passing through the first holes from the processing target by rotating the first tubular portion in a state in which the processing target shredded by the first shredding unit is accommodated in the first tubular portion; and

a first ridge that is provided on an inner circumferential surface of the first tubular portion and that extends in a direction in which a central axis of the first tubular portion extends,

wherein an inside of the first tubular portion is provided with a substantially cylindrical first rotating rod that has a central axis coinciding with a central axis of the first tubular portion and is rotatable about the central axis of the first rotating rod, and a first screw member that is helically provided around the first rotating rod and has a plurality of teeth formed in the first screw member,

an end portion of each tooth is constituted by a first side and a second side, the first side extending in a radial direction of the first tubular portion and the first rotating rod, the second side connecting an outer end of the first side to an inner end of the first side of a next tooth, and

the first rotating rod and the first screw member rotate such that the second side of the end portion of each tooth is located on a forward side with respect to a rotation direction of the first rotating rod and the first screw member, and the first side of the end portion of each tooth is located on a rearward side with respect to the rotation direction.

2. The separation device according to claim 1 ,

wherein “p” of said first ridges are present, “p” being an integer between 3 and 5 inclusive, and the “p” first ridges are arranged on the inner circumferential surface of the first tubular portion at regular intervals.

3. The separation device according to claim 1 , comprising a first air pipe for transferring the processing target shredded by the first shredding unit to the first separation unit with air pressure,

wherein the first air pipe has a first portion that extends in a first direction and a second portion that is connected to the first portion on a downstream side of the first portion and that extends in a second direction substantially orthogonal to the first direction.

4. The separation device according to claim 3 , comprising a first uneven surface that is present in a connecting portion between the first portion and the second portion of the first air pipe and with which the processing target transferred through the first portion collides.

5. The separation device according to claim 3 ,

wherein the first air pipe has a third portion that is connected to the second portion on a downstream side of the second portion and that extends in a third direction substantially orthogonal to the second direction.

6. The separation device according to claim 5 , comprising a second uneven surface that is present in a connecting portion between the second portion and the third portion of the first air pipe and with which the processing target transferred through the second portion collides.

7. The separation device according to claim 1 ,

wherein the first material is a plastic, and

the second material is a water-absorbent polymer.

8. The separation device according to claim 7 ,

wherein a weight ratio of the water-absorbent polymer adhering to the plastic immediately after processing by the separation device with respect to the plastic is 5% or less.

9. The separation device according to claim 1 ,

wherein the processing target is a disposable diaper.