Screw Conveyor Having Auxiliary Blades And Screw Discharge Decanter Centrifuge

Abstract

A screw conveyor having auxiliary blades (10), and a screw discharge decanter centrifuge. A hollow internal cylinder (4) is provided with a tapered section (11) and a straight section (7). Screw blades (6) are provided on the periphery of the inner cylinder (4), and several auxiliary blades (10) are provided between the screw blades (6), wherein the width of the auxiliary blades (10) is smaller than the pitch of the screw blades (6). Two adjacent auxiliary blades (10) are arranged in a staggered manner in a screw passage space to form a serpentine flow passage (15).

Claims

1. A screw conveyor having auxiliary blades, a hollow internal cylinder 4 is provided with a tapered section 11 and a straight section 7, a feed hole 3 is arranged on the tube wall near the tapered section 11, and screw blades 6 are arranged on the outer periphery of the inner cylinder 4, characterized in that a plurality of auxiliary blades 10 are arranged between the screw blades 6, the width of the auxiliary blades 10 is smaller than the pitch of the screw blades 6, and two adjacent auxiliary blades 10 are alternately arranged in the screw passage space to form a zigzag flow passage 15.

2. The screw conveyor having auxiliary blades according to claim 1, characterized in that the root of the auxiliary blade 10 is welded to the outer peripheral surface of the inner cylinder 4, one side is welded to the screw blade 6 on one side of the screw passage, and the other side is a certain distance t from the screw blade 6 on the other side of the screw passage.

3. The screw conveyor having auxiliary blades according to claim 2, characterized in that the distance t is 20% to 80% of the screw pitch p.

4. The screw conveyor having auxiliary blades according to claim 1, characterized in that the auxiliary blades 10 are planar straight blades or curved blades.

5. The screw conveyor having auxiliary blades according to claim 4, characterized in that the curved surface of the curved surface of the auxiliary blades 10 is convex in a direction consistent with the rotational direction of the rotary drum.

6. The screw conveyor having auxiliary blades according to claim 1, characterized in that the included angle between the auxiliary blades 10 and the central axis of the rotary drum is 0 to 45; or the included angle between the auxiliary blade 10 and the diameter of the rotary drum is 0 to 90.

7. A screw conveyor having auxiliary blades according to claim 1, characterized in that the auxiliary blade 10 is arranged in a screw passage behind the discharge hole 3.

8. The screw conveyor having auxiliary blades according to claim 1, characterized in that the auxiliary blades 10 are evenly distributed within each screw pitch, the adjacent two blades are arranged in parallel or staggered, and the side welding positions of the two auxiliary blades 10 on both sides of the screw blades 6 are staggered.

9. The screw conveyor having auxiliary blades according to claim 1, characterized in that the height of the auxiliary blades 10 is not higher than the height of the screw blades 6, and the height is equal or the height increases sequentially from the solid phase end to the liquid phase end.

10. A screw discharge decanter centrifuge, characterized in that a screw conveyor having auxiliary blades according to claim 1 is arranged in the outer cylinder 5.

Description

ILLUSTRATION WITH PICTURES

[0017] FIG. 1 is a schematic diagram of the existing horizontal screw centrifuge.

[0018] FIG. 2 is a schematic diagram of the structure of a horizontal screw centrifuge using the present invention.

[0019] FIG. 3 is a perspective view of the screw conveyor of the present invention.

[0020] FIG. 4 is a cross-sectional view of the screw conveyor A-A of FIG. 2.

[0021] FIG. 5 is the same as FIG. 4 and is a layout view of the auxiliary blade of the screw conveyor in Embodiment 2.

[0022] FIG. 6 is a perspective view of a screw conveyor of Embodiment 3 of the present invention.

[0023] FIG. 7 is a main view of FIG. 6.

[0024] FIG. 8 is a perspective view of a screw conveyor of Embodiment 4 of the present invention.

[0025] FIG. 9 is a main view of FIG. 6.

[0026] FIG. 10 is the same as FIG. 4 and is a layout view of the auxiliary blade of the screw conveyor in Embodiment 4.

[0027] In the FIG.: 1. Feed pipe; 2. Small end cover; 3. Discharge hole; 4. Inner cylinder. 5. Outer cylinder; 6. Screw blades; 7. Straight section; 8. Large end cover; 9. Overflow port; 10. Auxiliary blades; 11. Tapered section; 12. Solid phase outlet; 13. The first gap; 14. The second gap; 15. Flow passage.

SPECIFIC IMPLEMENTATION

[0028] Specific implementation of the invention will be described below in conjunction with the accompanying drawings.

Embodiment 1

[0029] As shown in FIGS. 3 and 4, the screw conveyor having auxiliary blades of the invention is provided with a plurality of auxiliary blades 10 between the screw blades 6 of the conventional screw conveyor, the width of the auxiliary blades 10 is smaller than the pitch of the screw blades 6, and the adjacent two auxiliary blades 10 are alternately arranged to further divide the originally continuous and complete screw passage space between the screw blades 6 into a zigzag flow passage 15, thereby prolonging the separation path length of the suspension and effectively improving the separation effect.

[0030] The auxiliary blade 10 added in this embodiment is a planar straight blade arranged along the radial direction of the screw conveyor, the bottom side edge of the root is welded to the outer periphery of the inner cylinder 4, and one side edge is welded to the screw blade 6, that is, a part of the left edge of the auxiliary blade 10 in each screw space is fixed with the screw blade 6 near the left side, a first gap 13 is left on the right side, with the width of t, the distance t is 20%-80% of the screw pitch p, and the right edge of the other part of the auxiliary blade 10 is fixed with the right screw blade 6 far from the feed pipe 1, so that a second gap 14 is left on the left side; That is, two adjacent auxiliary blades 10 in each circumferential space are interlaced and fixed with the left screw blades 6 and the right screw blades 6 so as to form a tortuous or serpentine flow passage 15 in each screw space. When the separation liquid flows through the passage, it is blocked by the auxiliary blades 10 to reduce the flow rate and be forced to turn continuously, thereby increasing the residence time of the liquid to be separated in the rotary drum during the centrifugal separation process. In this embodiment, a plurality of auxiliary blades 10 are uniformly arranged radially and equiangularly in a plurality of pitches of the screw conveyor.

[0031] When the invention is in operation, the suspended material to be separated enters the inner cylinder 4 of the screw conveyor from the feed pipe 1, and then enters between the outer cylinder 5 and the inner cylinder 4 which rotates at high speed from the discharge hole 3 of the screw conveyor, the solid-phase particles settle on the inner wall of the outer cylinder, the screw conveyor pushes the solid-phase particle sediment to the drying area at the small end of the rotary drum, namely the solid-phase end, and is extruded from the solid-phase outlet 12 of the rotary drum after being further extruded and dehydrated by the thrust force of the screw conveyor and the sediment centrifugal force. However, the separated clear liquid with lighter density moves along the inner cylinder 4 to the liquid phase end on the other side and settles, and is finally discharged from the overflow port 9.

[0032] By adding auxiliary blades 10 between the screw blades 6 and rotating along with the inner cylinder 4, the suspension entering the screw conveyor is separated from the liquid phase under the action of a huge centrifugal force field. Due to the existence of the auxiliary blade 10, the original method of only driving the liquid rotation by the screw blade 6 is changed, while the suspension entering between the inner and outer cylinders from the discharge hole 3 is driven by the auxiliary blade 10 so that the centrifugal force and rotation speed can be obtained immediately, and thus to accelerate the separation of the solid and liquid phases and improve the separation efficiency. At the same time, the auxiliary blade 10 also increases the equivalent settling area. According to the formula of separation factor Fr=r2/g, the above-mentioned increase in speed and area can significantly increase the separation factor Fr and achieve better separation effect.

[0033] The staggered auxiliary blades 10 arranged in the screw channel of the invention form a wave-shaped channel to increase the settling distance and residence time of the suspension to be separated in the rotary drum; under the condition that the diameter, rotational speed and length-diameter ratio of the rotary drum are the same, the equivalent settling area is increased, the settling distance of the particles is shortened, and the flow velocity of the suspension is increased at the same time, so that the solid particles can be fully separated from the liquid phase and settled, and the clear liquid with higher purity can be obtained, therefore, the filtration treatment of the solid particles is unnecessary in the latter process. The invention enhances the processing capacity and separation efficiency of the suspension which is difficult to separate from solid and liquid by modifying the existing horizontal screw centrifuge, with the advantages of low cost and saving production operation expenses.

Embodiment 2

[0034] As shown in FIG. 5, this embodiment changes the planar straight blade in Embodiment 1 to a curved blade, and the auxiliary blade 10 has a certain bending arc, and the curved convex direction of the curved surface is consistent with the rotation direction of the rotary drum, that is, the heavy phase particles in the suspension will move outward along the convex surface of the curved blade, so that the centrifugal force can be effectively increased and the heavy phase particles can be easily settled.

Embodiment 3

[0035] As shown in FIGS. 6 and 7, this embodiment deflects the auxiliary blade 10 arranged along the axial direction of the rotary drum in Embodiment 1 at a certain angle. In FIG. 7, the included angle between the auxiliary blade 10 and the central axis of the rotary drum is within 45, preferably 5 to 30. Adjacent blades are arranged in parallel, and the deflection direction is the same. In this embodiment, the auxiliary blade 10 is arranged in the screw passage at the rear of the discharge hole 3 to reduce the conveying resistance of the drying zone of the tapered section 11 of the rotary drum and facilitate the discharge of solid-phase materials.

Embodiment 4

[0036] As shown in FIG. 9 and FIG. 10, the deflection directions of the auxiliary blades 10 with the same deflection direction in Embodiment 4 are staggered, that is, the deflection direction of the auxiliary blades 10 welded on one side of the pushing surface of the screw blades 6 is opposite to the rotation direction, and the deflection direction of the auxiliary blades 1 welded on the back side is the same as the rotation direction. The implementation embodiment can improve the efficiency of solid ejecting and avoid the generation of dead angles or accumulation.

Embodiment 5

[0037] As shown in FIG. 10, the auxiliary blade 10 arranged along the diameter of the rotary drum in Embodiment 1 is deflected at a certain angle, and the included angle between the auxiliary blade 10 and the diameter in FIG. 10 is within 90, preferably 5 to 45. In this embodiment, four auxiliary blades 10 are provided in a screw pitch.

Embodiment 6

[0038] The height of the auxiliary blade 10 in each of the above embodiment is flush with the height of the screw blade 6, and the auxiliary blade 10 can assist in scraping solid particles from the inner wall of the outer drum, and can assist the screw blade 6 in pushing solid particles towards the drying zone at the small end of the drum. Of course, the height of the auxiliary blade 10 may also be lower than that of the screw blade 6 or increase in height from the solid phase end to the liquid phase end to assist the screw blade in pushing solid phase particles to the solid phase end.

[0039] The foregoing description is an explanation not a limitation of the invention, and the invention may be modified in any form without departing from the spirit of the invention. For example, the suspension is a kind of solid-liquid mixture, but it can also be fermentation broth, colloid, surfactant or emulsion, etc. For example, the auxiliary blade 10 may also be a circular, conical, curved or other shaped plate with a height not exceeding that of the screw blade 6, and it is only necessary to ensure that the flow passage 15 is formed in each screw circumferential space.