Aggregate washing systems, methods and apparatus
Aggregate washing systems are described including mechanisms for slurrying, washing and/or dewatering aggregate material.
1. An aggregate washing system, comprising:
a slurry mixer, said slurry mixer comprising:
a tank disposed at a first incline angle, the tank having a rearward portion with an aggregate material inlet for receiving aggregate material, the tank having a forward portion with a tank outlet comprising an opening in the tank, said rearward portion having a rear wall and first and second sidewalls, said rear wall having an upper edge disposed higher than said opening;
a water inlet for supplying water to said tank;
a propulsion assembly rotatably supported at least partially within said tank and extending from the rearward portion to the forward portion, wherein said propulsion assembly comprises a shaft, wherein said propulsion assembly comprises a plurality of paddles mounted to said shaft, each of said paddles extending radially outwardly from a rotational axis of said shaft and arranged in a generally spiral arrangement, wherein rotation of said propulsion assembly agitates said water and said aggregate material to form a slurry, wherein rotation of said propulsion assembly conveys said slurry from said rearward portion to the forward portion toward said tank outlet, wherein said rearward portion of the tank retains substantially all water that does not exit said opening of said tank outlet such that substantially all water exiting said rearward portion of the tank exits via said propulsion assembly advancing slurry toward said tank outlet;
a dewatering mechanism disposed to receive said slurry that passes through said opening from said tank outlet of said slurry mixer, said dewatering mechanism comprising:
a vibrating screen having a screen media deck for separating oversize material in said slurry from water and undersize material in said slurry, the screen media deck having a plurality of openings for receiving water and undersize material, the screen media deck having an end over which oversize material is deposited; and
at least a first washing element separate from said opening disposed to direct water toward said slurry on said screen media deck.
2. The aggregate washing system of claim 1 , wherein said screen media deck is disposed at a second incline angle.
3. The aggregate washing system of claim 2 , wherein said first incline angle is between 2 and 8 degrees, and wherein said second incline angle is between 0 and 4 degrees.
4. The aggregate washing system of claim 3 , wherein said screen media deck is vibrated at an acceleration greater than 3 g.
5. The aggregate washing system of claim 4 , wherein a length of said screen media deck is at least twice a width of said screen media deck.
6. The aggregate washing system of claim 2 , wherein at least one of said first and second incline angles is selectively adjustable.
7. The aggregate washing system of claim 1 , wherein said dewatering mechanism is mounted to said slurry mixer.
8. The aggregate washing system of claim 1 , wherein said dewatering mechanism is separate from said slurry mixer.
9. The aggregate washing system of claim 1 , further comprising a second washing element, said second washing element being disposed to apply water to slurry being deposited from the tank opening.
10. The aggregate washing system of claim 1 , further comprising a second washing element, said second washing element being disposed to apply water to a sidewall of said tank.
11. The aggregate washing system of claim 1 , further comprising a restriction plate mounted to said tank, wherein said restriction plate has a plurality of openings, wherein said restriction plate is disposed between said water inlet and said propulsion assembly.
12. The aggregate washing system of claim 1 , further comprising an underflume disposed beneath said screen media deck.
13. The aggregate washing system of claiml, wherein said propulsion assembly comprises an auger, wherein said plurality of paddles are disposed along a length of said shaft between said auger and said tank outlet.
14. An aggregate washing system, comprising:
a slurry mixer, said slurry mixer comprising:
a tank disposed at a first incline angle, the tank having a lower portion with an aggregate material inlet for receiving aggregate material, the tank having an upper portion with a tank outlet, said lower portion having a rear wall and first and second sidewalls, said rear wall extending to a height higher than said tank outlet;
a water inlet for supplying water to said tank;
a propulsion assembly rotatably supported at least partially within said tank and extending from the lower portion to the upper portion, wherein rotation of said propulsion assembly agitates said water and said aggregate material to form a slurry, wherein rotation of said propulsion assembly conveys said slurry from said lower portion to the upper portion toward said tank outlet, wherein said lower portion of the tank retains substantially all water that does not exit said tank outlet such that substantially all water exiting said lower portion of the tank exits via said propulsion assembly toward said tank outlet;
a dewatering mechanism disposed to receive said slurry from said tank outlet of said slurry mixer, said dewatering mechanism comprising:
a vibrating screen having a screen media deck for separating oversize material in said slurry from water and undersize material in said slurry, the screen media deck having a plurality of openings for receiving water and undersize material, the screen media deck having an end over which oversize material is deposited;
at least a first washing element disposed to direct water toward said screen media deck, wherein said screen media deck is disposed at a second incline angle, wherein said first incline angle is between 2 and 8 degrees, and wherein said second incline angle is between 0 and 4 degrees, wherein said screen media deck is vibrated at an acceleration greater than 3 g, wherein a length of said screen media deck is at least twice a width of said screen media deck.
15. The aggregate washing system of claim 14 , wherein at least one of said first and second incline angles is selectively adjustable.
16. The aggregate washing system of claim 14 , wherein said dewatering mechanism is mounted to said slurry mixer.
17. The aggregate washing system of claim 14 , wherein said dewatering mechanism is separate from said slurry mixer.
18. The aggregate washing system of claim 14 , further comprising a second washing element, said second washing element being disposed to apply water to slurry being deposited from the tank opening.
19. The aggregate washing system of claim 14 , further comprising a second washing element, said second washing element being disposed to apply water to a sidewall of said tank.
20. The aggregate washing system of claim 14 , further comprising a restriction plate mounted to said tank, wherein said restriction plate has a plurality of openings, wherein said restriction plate is disposed between said water inlet and said propulsion assembly.
21. The aggregate washing system of claim 14 , further comprising an underflume disposed beneath said screen media deck.
22. The aggregate washing system of claim 14 , wherein said propulsion assembly comprises a shaft, wherein said propulsion assembly comprises a plurality of paddles mounted to said shaft.