DE102014108722A1 - screw centrifuge - Google Patents

Abstract

The solid bowl centrifuge is used to continuously separate a mixture of flowable materials of different densities. It has a rotor drum (12) which can be rotated about a horizontal axis (16) and has a cylindrical drum section (18) and a conical drum section (20) and a screw conveyor (22) mounted on the same shaft (16) and mounted on a hollow shaft (16). 24) mounted screw spiral (26) for transporting the heavy phase to discharge openings (28) in the conical drum section (20), while at a cylindrical drum section (18) final end wall (40) at least one outlet opening (62) for the light phase with a weir (42) is provided. Extending downstream of the weir edge (56) overflowed by the light phase, there is a recirculation channel (52) for energy recovery having a curved bottom surface (58) whose tangent (T) is at a constant angle over most of the channel length (L) (α) to the normal (N) of the axis of rotation (16) of the rotor drum (12) and is in the range between 95 ° and 110 °.

Description

The invention relates to a solid bowl screw centrifuge according to the preamble of claim 1. It is based on one of the invention closest to the state of the art according to EP 2 551 019 A1 ,

To recover the kinetic energy of the outflowing material, numerous solutions are known from the prior art in which this is used to drive the rotational movement of the rotor. Examples include the aforementioned European patent application and the EP 2 598 251 . EP 2 551 021 or DE 10 2012 106 226 ,

In the screw centrifuge according to EP 2 551 019 A1 it is provided that the flow outlet channel has a bottom surface which is designed flat in sections and inclined to the tangential direction by an angle of 8 ° to 28 ° radially inwardly.

The invention has the object of developing a generic screw centrifuge so that in terms of energy recovery optimization is achieved.

The solution to this problem arises from the features of claim 1. Advantageous developments are the subject of the dependent claims.

The invention is explained below with reference to an embodiment which is shown in the drawing. In this show:

1 a schematic longitudinal section through a solid bowl centrifuge, in which a weir plate is indicated schematically at a discharge port for the light phase,

2 in an enlarged view a sectional view in the plane AA of 1 .

3 in a further enlarged view of the partially sectioned view of a weir plate with deflection channel according to the invention,

4 a 90 ° rotated view of the weir plate in the direction of arrow IV the 5 .

5 in a further enlarged scale a section through the flow channel of the weir plate 3 and 4 in a respect 3 90 ° tilted position,

6 the perspective exterior view of the weir plate,

7 the weir plate the 6 from diagonally below,

8th the weir plate of the side to be fastened to the end wall of the cylindrical drum section,

9 an oblique bottom view of the weir plate and

10 the representation of the weir plate with the essential dimensions of the Umlenkkanals.

Like the longitudinal section through half of the screw centrifuge 10 of the 1 shows, this has a rotor drum in a known manner 12 at both ends in radial bearings 14 supported (shown only at one end) and by a not further shown drive about a horizontal axis 16 is rotatable.

The rotor drum 12 has a cylindrical barrel section 18 and a conical barrel section 20 and is in a housing 44 accommodated.

In the rotor drum 12 is a screw conveyor 22 at a speed other than the drum speed around the axis 16 rotatably mounted. The required rotary drive is not shown. The screw conveyor 22 consists of a hollow shaft 24 , at the helix 26 for transporting the heavy phase to discharge openings 28 in the conical drum section 22 are attached.

By the in 1 left hollow shaft stub 30 the rotor drum 12 leads a not further shown inlet pipe for the mixture to be separated (task suspension) axially into a hollow shaft 24 trained task chamber 32 , from the discharge openings 34 in the workroom 36 the spiral of the spiral 26 to lead.

In operation of the centrifuge 10 promotes the spiral of the spiral 26 the specific heavy phase (thick matter) in the conical drum section 20 from which they pass over the discharge opening 28 is delivered. The liquid, light phase (Zentrat) flows in the opposite direction to the cylindrical drum section 18 final end wall 38 with drainage holes 40 for the light phase, each with a weir 42 is assigned to the front wall 38 is attached.

The 3 to 9 show an inventively designed weir 42 with a weir plate 46 that has two long holes 48 adjustable on the front wall 38 can be attached.

One piece with the weir plate 46 is a deflecting device designed according to the invention 50 trained by the weir plate 46 relative to the front wall 38 protrudes outwards. In each diverter 50 is a designed according to the invention deflection 52 formed, which serves to recover energy of the effluent and through a to the weir plate 46 parallel outer wall 54 closed is. At every defense plate 46 is an in 3 shown weir edge 56 formed, which is overflowed in a known manner from the effluent centrate and a curved bottom surface 58 Has. The over the weir edge 56 outflowing centrate flows through the deflection channel 52 to an outflow opening 60 whose width B ( 3 ) inversely proportional to the slope S of the ground surface 58 is and is preferably about 20 mm. In 3 and 4 the throughput dependent attack height H is indicated. The product of B × H becomes the outflow cross section of the discharge opening 60 certainly.

As 5 shows, the deflection channel 52 through an outer surface 62 and an inner surface 64 limited in the flow direction up to the discharge opening 60 form a constriction, which accelerates the effluent centrate. By the smallest possible width B of the outflow opening 60 the diameter of the weir is significantly influenced as a function of the throughput by the head H ("cresting").

In 10 are the geometric parameters for the deflection device 50 with its deflection channel 52 located. In this mean:

LIST OF REFERENCE NUMBERS

56

 weir edge

58

 floor area

T

Tangent to the ground surface 58 in the area L

T '

Tangent to the ground surface 58 in the range L '

N

Normal to the axis of rotation 16

L

Total length of the deflection channel 52 (L = L '+ L'')

S

Slope of the ground surface 58 of the deflection channel 52

O

Inflow opening in the deflection channel 52

U

 Transfer surface

m

Middle of the discharge opening 60

e

 Offset to center m

a

 constant angle between T and N.

a '

 constant angle between T 'and N'

M

Fluid mantle of the weir edge 56 overflowing centrate

R

Radius of curvature of the ground surface 58 , at the same time inner radius of the liquid mantle M

To optimize the energy recovery has the bottom surface 58 of the deflection channel 52 on the largest part L 'of the entire channel length L with its tangent T to the normal N to the axis of rotation 16 the rotor drum 12 a constant angle α, which is between 95 ° and 110 ° and in the optimal case is 100 ° and was determined empirically.

The 3 and 10 further show that the deflection channel 52 at his in the outflow 60 opening end on the part length L '' one to the axis of rotation 16 angled curvature 66 with a slope S has. In this range, α '≠ α, preferably α'<α, whereby a constriction of the deflection channel 52 is formed, which accelerates the flow.

In 10 It is further shown that the radius of curvature R of the curved bottom surface 58 the inner radius of the liquid jacket M of the weir edge 56 overflowing, light phase corresponds.

To optimize the length L of the deflection channel 52 is how the 5 and 10 show the center m of the inflow opening O on the end wall 38 in the deflection channel 52 shifted by the eccentric offset E in the direction of rotation. The offset E is approximately between 5 mm and 20 mm.

Finally, can 10 be taken that the outer surface 62 of the deflection channel 52 parallel to the outer surface of the front wall 38 of the cylindrical barrel portion 18 runs.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2551019 A1 [0001, 0003]
• EP 2598251 [0002]
• EP 2551021 [0002]
• DE 102012106226 [0002]

Claims (11)

A solid bowl centrifugal centrifuge for continuously separating a mixture of flowable materials of different densities, comprising one about a horizontal axis ( 16 ) rotatable rotor drum ( 12 ) with a cylindrical drum section ( 18 ) and a conical drum section ( 20 ) and one stored therein, around the same axis ( 16 ) rotating screw conveyor ( 22 ) with on a hollow shaft ( 24 ) mounted spiral ( 26 ) for transporting the heavy phase to discharge openings ( 28 ) in the conical drum section ( 20 ), while at one of the cylindrical drum section ( 18 ) final end wall ( 38 ) for the light phase at least one outflow opening ( 40 ) with a weir ( 42 ) is provided, wherein in the flow direction behind the overflowed from the light phase weir edge ( 56 ) a deflection channel ( 52 ) for the energy recovery, characterized in that the deflection channel ( 52 ) a curved bottom surface ( 58 ) whose tangent (T) on the largest part (L ') of the channel length (L) has a constant angle (α) to the normal (N) of the axis of rotation ( 16 ) the rotor drum is in the range between 95 ° and 110 °. Solid bowl centrifuge according to claim 1, characterized in that the angle (α) is in the range between 98 ° and 103 °. Solid bowl centrifuge according to claim 2, characterized in that the angle (α) is 100 °. Solid shell screw centrifuge according to one of the preceding claims, characterized in that the radius of curvature (R) of the curved bottom surface (R) 58 ) the inner radius (R) of the liquid jacket (M) of the weir edge ( 56 ) overflowing, light phase corresponds. Solid bowl centrifuge according to one of the preceding claims, characterized in that the width (B) of the rearwardly directed outflow opening ( 60 ) is dimensioned so that the raid height (H) at full throughput is greater than the slope (S) of the bottom surface ( 58 ) of the deflection channel ( 52 ) and thus affects the weir diameter such that with increasing throughput of the inner diameter of the liquid sheath (M) is smaller. Solid bowl centrifuge according to claim 5, characterized in that the width (B) of the outflow opening ( 60 ) in the order of 11 mm 27 mm is located. Solid bowl centrifuge according to one of the preceding claims, characterized in that the outer surface ( 62 ) of the deflection channel ( 52 ) parallel to the end wall ( 38 ) of the cylindrical drum section ( 18 ) runs. A solid bowl centrifuge according to claim 7, characterized in that the inner surface ( 64 ) of the deflection channel ( 52 ) a curvature ( 66 ), which with the outer surface ( 62 ) a flow accelerating constriction of the deflection channel ( 52 ). Solid bowl screw centrifuge according to claim 8, characterized in that the deflection channel ( 52 ) at its in the outflow ( 60 ) opening end (L '') one to the rotation axis ( 16 ) angled curvature ( 66 ) has such that for the angle between T 'and N: α' ≠ α. Solid shell screw centrifuge according to one of the preceding claims, characterized in that in order to optimize the length (L) of the deflection channel ( 52 ) the center (m) of the inflow opening (O) on the end wall ( 38 ) in the deflection channel ( 52 ) is shifted by the eccentric offset (E) in the direction of rotation. Solid bowl centrifuge according to claim 10, characterized in that the offset (E) is between 5 mm and 20 mm.

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