Screw press
The invention relates to a screw press ( 1 ) comprising a shaft ( 4 ) and a spiral helix ( 5 ) provided thereon, wherein the helix ( 5 ) goes over in the inlet region ( 2 ) of the screw press ( 1 ) into a freely projecting helix ( 8 ). It is principally characterized in that a tube ( 9 ) is provided in the inlet region ( 2 ) of the screw press ( 1 ). As a result, on the one hand the screen area can be increased greatly in size, on the other hand the co-rotation of the suspension with the shaft can be reduced or avoided.
1. A screw press comprising:
a screw including a shaft with helical flight rotatable about an axis;
a casing shell surrounding the screw between an inlet end of the screw and an outlet end of the screw;
an inlet casing connected to the casing shell for delivering a suspension to the inlet end of the screw;
an outlet casing connected to the casing shell for discharging a pressed suspension from the outlet end of the screw;
wherein
the inlet end of the screw includes a flight in the inlet casing;
the flight at the inlet end of the screw freely projects from the screw shaft; and
a screen pipe extends coaxially within the freely projecting flight;
whereby the freely projecting flight rotates closely around the screen pipe as the screw rotates within the casing shell.
2. The screw press of claim 1 , wherein the screw press includes a frame and the screen pipe is connected to the frame in a rotationally fixed position within the freely projecting flight.
3. The screw press of claim 2 , wherein
the shaft includes a shaft journal extending axially through the inlet casing and supported in a bearing carried by the frame;
the screen pipe coaxially extends in spaced relation around the shaft journal; and
a filtrate channel is defined in the space between the screen pipe and the shaft journal.
4. The screw press of claim 3 , wherein the filtrate channel is defined between the screen pipe and another pipe that extends coaxially around the shaft journal.
5. The screw press of claim 3 , wherein the screen pipe has a rough surface that counteracts co-rotation of suspension with the freely projecting flight.
6. The screw press of claim 2 , wherein
the inlet casing is connected to the frame and has a vertically oriented inlet branch;
the screen pipe extends axially through the vertical branch to a rigid connection on the frame;
a filtrate channel extends axially within the screen pipe to the frame; and
a filtrate collection volume is provided at the connection of the screen pipe to the frame.
7. The screw press of claim 6 , wherein the filtrate channel is divided into a plurality of filtrate channels that are separated from each other by web plates.
8. The screw press of claim 2 , wherein
the screen pipe coaxially extends in spaced relation around the shaft; and
a filtrate channel is defined in the space between the screen pipe and the shaft.
9. The screw press of claim 8 , wherein the filtrate channel is defined between the screen pipe and another pipe that extends coaxially around the shaft.
10. The screw press of claim 1 , wherein the shaft includes a shaft journal extending axially through the inlet casing, surrounded by the freely projecting flight.
11. The screw press of claim 1 , wherein the shaft includes a shaft journal extending axially through the inlet casing, surrounded by the screen pipe.
12. The screw press of claim 1 , wherein the screen pipe has a rough surface that counteracts co-rotation of suspension with the freely projecting flight.
13. The screw press of claim 1 , wherein the screen pipe includes a filtrate channel.
14. The screw press of claim 13 , wherein the filtrate channel is formed between the screen pipe and another coaxial pipe within the screen pipe.
15. The screw press of claim 1 , wherein
the shaft includes a shaft journal extending axially through the inlet casing;
the screen pipe coaxially extends in spaced relation around the shaft journal; and
a filtrate channel is defined in the space between the screen pipe and the shaft journal.
16. The screw press of claim 15 , wherein the filtrate channel is defined between the screen pipe and another pipe that extends coaxially around the shaft journal.
17. The screw press of claim 15 , wherein the screen pipe has a rough surface that counteracts co-rotation of suspension with the freely projecting flight.