Archimedes screw separation plant for treating slurry

1. An Archimedes screw plant ( 10 ) for separating slurry into liquid and solid fractions, the plant ( 10 ) comprising:

a tubular sifting device ( 11 ), having a vertical axis (X), provided with a filtering punched wall ( 18 ), said wall housing inside it vertical pushing means ( 12 , 13 ) provided with coils ( 12 *, 13 *), said vertical pushing means ( 12 , 13 ) being able to vertically move and compress slurry; said vertical pushing means ( 12 , 13 ) comprising at least two pushing elements ( 12 , 13 ) substantially conformed to an Archimedes screw (augers) that, substantially, interpenetrate each other;

a slurry feeding device ( 31 );

a first evacuating device ( 21 ) for the liquid fraction after its separation from the solid fraction, separation substantially occurring inside said tubular sifting device ( 11 );

a second evacuating device ( 19 , 22 ) for substantially dry separated solid after its separation from the liquid fraction, separation substantially occurring inside said tubular sifting device ( 11 ); a compacted product being upwardly and vertically released (F2) from said tubular sifting device;

the plant ( 10 ) characterized in that

said tubular sifting device ( 11 ) comprises inside it said second evacuating device, said second evacuating device comprising an upper compaction chamber ( 19 ) for the separated solid where a solid plug of product is formed; at least a first portion ( 19 B) of said compaction chamber ( 19 ) being without said pushing elements ( 12 , 13 ) and said filtering punched wall ( 18 );

and in that

said compaction chamber is provided with an upper exhaust opening ( 22 ) in a vertically upper end thereof for the separated solid, said upper opening ( 22 ) being provided with an auxiliary contrast element ( 40 ) for forming said solid plug of product by counter pressure, said auxiliary contrast element ( 40 ) acting simultaneously upon all of the separated solid in transit from said upper opening ( 22 ).

2. The plant ( 10 ), as claimed in claim 1 , characterized by the fact that the size of said upper opening ( 22 ) is substantially equal to that of any cross section (ST) of the tubular sifting device ( 11 ).

3. The plant ( 10 ), as claimed in claim 1 , characterized in that the entire compaction chamber ( 19 ) is without said pushing elements ( 12 , 13 ), at least a second portion ( 19 A) of said compaction chamber ( 19 ) being provided with said filtering punched wall ( 18 ).

4. The plant ( 10 ), as claimed in claim 1 , characterized in that said contrast element ( 40 ) comprises at least one counter pressure device ( 41 , 42 ), which presents a plurality of adjacent segments ( 41 A, 41 B, 41 C, 41 D, 41 E, 41 F, 42 A, 42 B, 42 C, 42 D, 42 E, 42 F) attached to a common edge ( 51 , 52 ) and free to flex independently of each other when subjected to the pushing action from the solid material exiting the compaction chamber ( 19 ).

5. The plant ( 10 ), as claimed in claim 4 , characterized in that said at least one counter pressure device ( 41 , 42 ) comprises a deformable sheet (PD), which internally houses at least one respective elastic layer (LM, LM*, LM**).

6. The plant ( 10 ), as claimed in claim 5 , characterized in that the shape of said at least one respective elastic layer (LM, LM* LM**) substantially reproduces the shape of said at least one counter pressure device ( 41 , 42 ).

7. The plant ( 10 ), as claimed in claim 4 , characterized in that said contrast element ( 40 ) comprises at least two counter pressure devices ( 41 , 42 ) side by side to each other.

8. The plant ( 10 ), as claimed in claim 4 , characterized in that said at least one counter pressure device ( 41 , 42 ) comprises at least two layers (LM* LM**) equal to or different from each other both in material and thickness.

9. The plant ( 10 ), as claimed in claim 8 , characterized in that each layer (LM LM* LM**) is composed of equal or different segments, to or from each other, so that each segment ( 41 A, 41 B, 41 C, 41 D, 41 E, 41 F, 42 A, 42 B, 42 C, 42 D, 42 E, 42 F) can best respond to the different stress factors of the material exiting from said upper opening ( 22 ).

10. The plant ( 10 ), as claimed in claim 1 , characterized in that the compacted product is vertically released in an upward direction through an upward facing opening.

11. The plant ( 10 ), as claimed in claim 10 , characterized in that a vertical axis of the upward facing opening is parallel to longitudinal axes of the pushing means ( 12 , 13 ).