EP2658656A1

EP2658656A1 - Solid bowl screw centrifuge having an overflow weir

Info

Publication number: EP2658656A1
Application number: EP11794487.6A
Authority: EP
Inventors: Stefan Terholsen
Original assignee: GEA Mechanical Equipment GmbH
Current assignee: GEA Mechanical Equipment GmbH
Priority date: 2010-12-27
Filing date: 2011-12-13
Publication date: 2013-11-06
Anticipated expiration: 2031-12-13
Also published as: DK2658656T3; DE102010061563A1; EP2658656B1; WO2012089492A1

Abstract

The invention relates to a solid bowl screw centrifuge having at least one device (23') for discharging clarified liquid out of a drum (3), a. wherein the device (23') has at least one or more through-passage openings (15) in a drum lid (17), b. wherein preferably the at least one through-passage opening (15) is assigned in each case a weir plate (19) which has and forms in each case an overflow weir (21) at its radial inner edge, c. wherein the weir plate (19) has a material cutout which forms at least a part of a discharging channel (25) or an entire discharging channel (25), and d. wherein the discharging channel (25) is formed such that it deflects a flow emerging from the drum at an angle > 0° with respect to the rotational axis.

Description

Solid bowl centrifuge with overflow weir

The invention relates to a solid bowl screw centrifuge according to the preamble of claim 1.

Solid bowl centrifuges are known in various embodiments.

Thus, DE 102 03 652 B4 discloses a solid bowl screw centrifuge with a device for discharging clarified liquid from a drum, the one

Drum cover having a passage to which a throttle device, in particular a throttle plate, is assigned, whose distance from the passage is variable. In this case, the passage further nozzles are assigned to the outlet of the clarified liquid, which are aligned for energy saving inclined to the radial direction through the drum axis.

Nozzles on solid bowl centrifuges and their effect of energy saving with a corresponding orientation inclined to the drum axis are further known from DE 39 04 151 A1.

The publication "Patent Abstracts of Japan", number 1 1 179236 A, in contrast, discloses that passage openings in the drum cover, which are each partially closed by a weir plate, which form an overflow weir, baffles can be assigned which of the liquid emerging from the drum The baffles are mounted on the outside of the overflow weir, for example, on the weir plates, for example, they are formed as flat sheets which are aligned parallel to the drum rotation axis, with the plane in which the flat Plates lie, the drum axis does not intersect and about an angle of about 45 ° with the radially extending straight line, which runs through the drum rotation axis and the respective passage opening. It is also known - as from US 2004/0072668 A1 or WO 2008/1 38345 A1 - instead of an overflow weir on the weir plate of the passage opening to assign a housing, in which case the overflow weir or a nozzle formed in a sloping side of the housing at the passage opening become. These

However, 5 constructions have the disadvantage that co-rotating, relatively complicated shaped liquid chambers are formed on the Au ßenseite the drum lid, which form part of the rotating system, so that the clarification or separation process continues in the liquid chambers. For this

Separation process can result in unwanted deposits in the chambers,

10 which cause cleaning problems and imbalance problems.

Starting from this prior art, the object of the invention is to provide a solid shell screw centrifuge optimized with regard to energy saving, which can also be regarded as advantageous from a hygienic point of view.

L5

The invention solves this problem by the subject matter of claim 1.

Thereafter, it is provided that the weir plate has a material recess, which at least part of a discharge channel or a complete

10 discharge channel forms, wherein the discharge channel is formed such that it deflects out of the drum flow at an angle ß> 0 ° to the axis of rotation.

In the following, some special advantages of the claimed and described embodiments will be summarized.

First, a main advantage of the various configurations with

Deriving channels explained. Liquids with fibrous solids may, in a complicated designed passage opening to the problem that the 50 fibers on exiting the housing in certain areas, so in for the

Take up the weir plate provided grooves stuck. This can happen in particular during downshifts, when the liquid ring collapses suddenly due to small centrifugal forces but constant gravitational force and the drum empties spontaneously. Especially in cases as Device for draining liquid, as in the prior art

have been variously proposed, can be easily

Form product deposits, since a near-surface layer flow is formed, which can not rinse the central regions of the housing of solids 5. Due to the open design of the drainage channels, the o.g.

Disadvantages avoided.

According to the proposed new facilities for the discharge of liquid from the centrifuge drum deposits are also avoided because the liquid

10 over the entire liquid cross section and thus also near the wall of the

Outlet flows and thus can entrain solid particles. This is an advantage from a sanitary point of view but also constructive with regard to the reduced risk of the formation of potential imbalances from non-rotationally symmetrical

deposited solid. Such uneven solid deposits can become

15 u. a. form when the centrifuge is stopped and by the random

Standstill position of the rotor solids through the collapsing

Liquid ring are flushed out asymmetrically or even the solid itself flows out of the outlet elements asymmetrically.

It is further advantageous in the variants of the invention with the open drainage channel that the present invention leaves the overflow weir directly to the weir plates on the drum cover and only the liquid which has already left the rotating system via the weir weir is deflected in the circumferential direction , After leaving the drum, no clearing effect can occur, the whole

> 5 emerging liquid jet is rather through the deflection in

Deflected circumferential direction.

A further advantage is that it is also avoided by the chosen constructions that the liquid contained in the housing exert too high unwanted additional 50 centrifugal forces on the drum. In particular, the outlet or

Discharge channels can not fill with liquid, it forms only a relatively thin layer of liquid that exerts relatively little additional forces. By extending one or both elements "bottom wall" and "one or both side walls" with the above-described inclination in the direction

Rotation center can be ensured that the deviation of the

Liquid outflow is minimized from the ideal tangential direction.

5

The inclined passage openings in the end-side drum wall combined with a weir plate without outlet element or with a weir plate which has a "grooved" contour and in particular the inserted into the drum wall insert have the advantage that the space required in the axial direction for the

10 rotor is relatively small. This makes it possible to minimize the use of material for the rotor, the frame carrying the rotor and the housing surrounding the rotor.

In addition, the storage distance is shortened, which can be achieved due to the improved machine dynamics properties higher rotational speeds of the centrifuge, as the speed limiting natural frequencies to higher values

15 move.

The design with an insert embedded in the drum wall offers the advantage that adjustments of the inner contour to product properties and also to operating parameters, such as, for example, the throughput capacity without changes of the drum wall are possible. The inserts can also be easily exchanged.

Further advantageous embodiments can be found in the remaining subclaims.

> 5 Hereinafter, the invention will be described with reference to the drawings.

Show it:

1 is a schematic view of a known Vollmantel-

Screw centrifuge; and

Figs. 2-14 show various views, sections, representations and embodiments 50 of devices for draining liquid from one

Centrifuge drum formed on a drum lid of a centrifuge drum. The figures are partially a schematic representation of a

Assigned coordinate system, in the center of which the axis of rotation D of a centrifuge drum is located and in which the arrow U, the direction of rotation of a

Centrifuge drum features. The line D 'denotes a parallel to the

5 axis of rotation D and the arrow R the radial direction perpendicular to the axis of rotation D.

Fig. 1 should first illustrate the basic structure of a solid bowl centrifuge. The drive together with control, a hood and other for the expert obvious elements are not shown here.

10

Fig. 1 shows a solid bowl screw centrifuge 1 with a preferably horizontal axis of rotation D rotatable drum 3, in which a likewise rotatable screw 5 is arranged. The drum 3 and the screw 5 each have a substantially cylindrical portion and a conically tapered L5 portion.

An axially extending centric inlet pipe 7 serves to supply the

Centrifugally good through a distributor 9 in the centrifugal space 1 1 between the screw 5 and the drum. 3

0

For example, if a muddy slurry is fed into the centrifuge, coarser solid particles settle on the drum wall. Further inward, a liquid phase forms.

> 5 The screw 5 rotates at a slightly lower or greater speed than the drum 3 and promotes the ejected solid to the conical portion out of the drum 3 to the solids discharge 1 third

The liquid flows against the larger drum diameter at the rear 50 end of the cylindrical portion of the drum 3 and is discharged through a weir, the passage openings 1 5 in a drum cover 1 7, wherein each passage opening 1 5 a weir plate 1 9 is assigned here radially adjustable on the Au ßenseite the drum cover is mounted. The inner radial edge of the weir plate thus defines an overflow edge and thus also the actual weir or overflow weir 21. The passage opening 1 5 and the weir plate 1 9 with the overflow weir 21 form in Fig. 1 respectively in their

Interaction a "device 23 for the discharge of liquid from the

It is preferably provided to provide not only one of these devices 23 on the drum cover, but to distribute at least one radius in each case several of these devices in the circumferential direction.

Advantageously, all of the above variants are supplemented by a radial adjustability of the weir plates 19. This adjustability can be achieved e.g. also simple manner via hole patterns 37 (see Fig. 5) with selectable radial

Holes or holes on the weir plate and corresponding holes on the drum cover and bolts or the like. Can be realized to thereby allow easy adjustment of the liquid level diameter in the drum. The hole patterns are shown for the sake of simplicity only in Fig. 5, but preferably provided in all embodiments.

According to the invention, e.g. 1, the drum cover and / or the at least one device 23 for discharging liquid from the centrifuge drum can be replaced by a corresponding device 23 'of FIGS. 2 to 14 in the case of a solid bowl screw centrifuge.

First, the embodiments of FIGS. 2 to 4 will be described.

3 and 4 show plan views of two different devices 23 'and Fig. 2 shows a section through a corresponding device 23'. These are each modified means 23 'for discharging liquid from a centrifuge drum, which in turn one or more components

Passage opening (s) 1 5 in a drum cover 17 on a certain radius au ßerhalb the axis of rotation D have and each one assigned

Passage opening 15 fully or partially covering weir plate 1 9.

The devices 23 'further each have a discharge channel 25, which is formed on the respective weir plate 1 9 and / or formed integrally therewith. The weir plate 1 9 of Fig. 2 to 4 is preferably directly au Shen on

Drum cover 1 7 aligned parallel to the drum cover 17 at.

The weir plates 1 9 of Fig. 2 each have to the center of rotation D out a 5 the passage opening 15 partially "again" radially outward Shen further free releasing

Material recess 27 on.

As a result, the weir 21 is placed in this area on a further au Shen at the bottom of the recess radius R27.

10

The material recess 27 on the outer side of the weir plate 1 9 preferably passes in alignment with the discharge channel 25. It thus forms the beginning of the discharge channel 25 itself.

15 The discharge channel 25 can (see Fig. 5) only from the

Material recess 27 are made when the weir plate 1 9 is sufficiently thick and the material recess corresponding to an inclination angle γ (see Fig. 6) to the rotational direction U, is aligned. Preferably, the material recess but by a the weir plate on its side facing away from the drum 1 side

10 extending gutter element 29 extended.

The discharge channel 25 is open at least on its radially inward-facing side and preferably also at its end facing away from the weir plate 1 9.

> 5

The discharge channel has lateral deflection walls 31 a, 31 b, which may be flat or bent.

The cross section of the drainage trough 25 - see e.g. Fig. 2 - can be designed in various ways. It is essential that the discharge channel 25 radially to

inside towards the axis of rotation D preferably completely (especially in

Flow direction of the exiting liquid) is open. Especially the completely inwardly open design is insensitive to contamination, the Contamination tendency continues by rounding off corners of the

Deriving trough 25 can be reduced.

The cross-section of the discharge channel 25 can be configured correspondingly square (FIG. 3) or rather rounded (FIG. 4). The cross-section can be constant over the length of the discharge channel or change.

According to Fig. 5 and 6, the drainage channel 25 is formed on structurally particularly simple and inexpensive, and again insensitive to contamination manner only in that the weir plates 1 9 each no lengthening

Ridge element 29 but that only the material recess 27 is provided on the weir plate, the side walls 31 a, 31 b are not axially aligned in the circumferential direction but opposite to the direction of rotation obliquely or bent, in order to redirect the outflowing flow counter to the direction of rotation. The weir plates 19 of FIGS. 5 and 6 are due to their

Design for the sake of simplicity hereinafter also referred to as "grooved" weir plates 19.

In the means for discharging liquid 23 'of Fig. 2 to 4 with "square" or "rounded" discharge channel 25 this is "inside and au ßerhalb" of the weir plate 1 9, in the "grooved" weir plate 1 9 of FIG. 5 and 6 is the

Ableitungsrinne 25, however, only "inside" the weir plate 1 9

educated. The overflow weir 21 of the embodiments according to FIGS. 2 to 6 is located at the entrance of the liquid in the material recess 27 of the weir plate 1 9, which thus determines the diameter of the liquid level in the drum.

According to FIGS. 2 to 6, the bottom wall 35 of the channel 25 extends in a straight line in the tangential direction.

The liquid outlet of the grooves is at an angle ß to the rotation axis D with ß> 0 ° and ß preferably> = 20 ° and by an angle γ relative to the rotational direction U tilted. For the angle γ, the following applies preferably: γ> = 0 ° and γ <90 ° and particularly preferably: γ> = 0 ° and γ <30 °. This embodiment is preferred.

Alternatively, it is also conceivable that the angle γ is smaller than 0 °,

for example, less than -30 ° (not shown), even if this occurs an exit of the liquid phase in the direction of the drum cover itself.

However, it is also conceivable that the depth of the channel (s) 25 changes

(in particular with respect to the plane corresponding to Fig. 2, not shown). FIGS. 7 and 8 show further embodiments of outlet elements which have a discharge channel 25 which is open radially inwardly.

According to FIGS. 7 and 8, it is provided by way of example that the channel element 29 of the discharge channel has a shape running concentrically on a circular arc section with a constant radius. Therefore, in particular, the bottom wall 35, in whole or in sections, a rounded, in particular concentric to

Rotational center run out of shape.

While Figs. 2 to 8 relate to embodiments in which at least on one side of completely open drainage channels 25 in a weir plate 1 9 and preferably in an axial groove-like extension - channel element 29 -

Weir plate 1 9 are formed, it is also conceivable to deflect the effluent from the drum 1 liquid in the circumferential direction, that the drum cover itself has passage openings 1 5, which do not extend in the axial direction, but which with respect to the longitudinal axis D of the drum to a Angle ß are inclined. The passage openings 1 5 are thus, for example, although cylindrical in itself, but oriented obliquely to the axis of rotation, wherein the angle δ between the axis of rotation D and the central axis of the passage openings 1 5 sections in each case greater than 0 ° and less than 90 °.

For the angle of inclination, δ preferably applies: δ> = 20 ° and δ <= 60 ° (FIGS. 9 and 10). Alternatively, the passage opening can also be curved in itself. Mixed forms of the described embodiments are readily feasible. Each of the "inclined" passage openings 15 is preferably covered by a corresponding weir plate 19 up to a predetermined radius, whereby this covering weir plate 19 can itself be a "straight" one.

Have overflow edge or weir edge 21, which is on a predetermined, preferably by means of hole patterns or the like. Adjustable radius.

It is also conceivable in this case to combine the "inclined" passage openings with weir plates 1 9 in the manner of FIGS. 2 to 8, ie with weir plates which have a kind of discharge channel 25, at least in the form of a channel contour, in order to achieve such a particularly advantageous Derivation behavior.

Thus, FIGS. 1 and 12 show embodiments with inclined passage openings 15 in the end-face drum wall 17 and weir plates 19, which have a "grooved" bevelled contour in the manner of FIG. 6 or 7.

Fig. 1 3 further shows an embodiment which advantageously the inclined

Through openings 1 5 in the frontal drum wall 1 7 each with one of the weir plates 1 9 combined with a channel element 29 in the manner of Fig. 2 or 3.

FIG. 14 further illustrates the possibility in which

Passage openings 1 5 of the drum cover insert inserts 41,

For example, threaded inserts, which are screwed into screw holes of the drum cover 1 7, these inserts themselves in axial holes of the

Drum cover may be used and then in turn may have holes 43 which are inclined to the drum axis D and D 'aligned. Fig. 14 shows a variant in which parallel to the longitudinal axis D of the drum extending bores 43 are formed in the end-side drum wall, which are each provided with an insert 41 having a bore 43 in the interior, the central axis with respect to the rotational direction U of the drum by an angle δ: δ> = preferably 1 5 ° and δ <= preferably 75 ° inclined (FIG. 14)

The inserts 41 in the drum wall or in the drum cover can be configured in various ways. Thus, the axial extent of the insert 41 may correspond to the axial thickness of the drum wall or the axial thickness of the drum cover (FIG. 14).

It is also theoretically possible to implement a variant of the insert 41, in which this - for example -. with a plate-like flange portion or the like. - Projecting beyond the end face of the drum (not shown). Also conceivable is an insert 41 in the drum wall - as described above, with a Abspritzkante (not shown).

Particularly advantageous is the combination of the insert 41 in the drum wall of the type of Fig. 14 in combination with a device 23 'of FIG. 2 to 5, ie with a weir plate according to one of the above Fig. 1 to 13.

reference numeral

Solid bowl centrifuge 1

Drum 3

Snail 5

Inlet pipe 7

Distributor 9

Centrifugal space 1 1

Solids discharge 13

Passage openings 15

Drum cover 17

Weir plate 19

Overflow weir 21 Discharge device 23, 23 '

Discharge channel 25

Material recess 27

Channel element 29

Deflection walls 31 a, 31 b

Bottom wall 35

Hole patterns 37

Inserts 41

Bores 43

Outside 45

Radius R27

Radial direction R

Rotation direction U

Rotation axis D

Parallel to D D '

Inclination angle α, ß, δ, γ

Directions x, y

Claims

claims

1 . A solid bowl centrifuge with at least one device (23 ') for discharging clarified liquid from a drum (3),

a. wherein the device (23 ') at least one or more

Having passage openings (15) in a drum cover (17), b. wherein preferably the at least one passage opening (15)

in each case a weir plate (19) is assigned, which has at its radial inner edge in each case an overflow weir (21) and formed, characterized in that

c. the weir plate (19) has a material recess, which

forms at least a part of a discharge channel (25) or a complete discharge channel (25),

d. wherein the discharge channel (25) is designed such that it deflects flow emerging from the drum at an angle β> 0 ° to the axis of rotation.

2. full-bowl screw centrifuge according to claim 1, characterized in that the material recess (27) on the side facing away from the interior of the drum outer side (45) of the weir plate (19) is preferably aligned in an attached to the weir plate or molded channel element (29), such that the discharge channel (25) is formed from the material recess (27) and the channel element (29).

3. Solid bowl centrifuge according to one of the preceding claims, characterized in that the discharge channel (25) is open at least on its radially inwardly facing side.

4. Solid bowl screw centrifuge according to one of the preceding claims, characterized in that the discharge channel (25) is designed to be open at its end facing away from the weir plate (19).

5. Solid bowl centrifuge according to one or more of

preceding claims, characterized in that the Channel element (29) is formed radially inwardly completely or partially open.

6. solid bowl centrifuge according to one of the preceding claims, characterized in that the discharge channel (25) lateral

Deflection walls (31 a, 31 b), which are aligned such that they the emerging from the drum flow at an angle γ to

Turn the direction of rotation (U).

7. Solid bowl screw centrifuge according to one of the preceding claims, characterized in that the cross section of the discharge channel (25) is configured angular or rounded.

8. Solid bowl screw centrifuge according to one of the preceding claims, characterized in that the discharge channel (25) has a bottom wall (35) which extends in a straight line in the tangential direction (U).

9. solid bowl screw centrifuge according to one of the preceding claims, characterized in that the weir plate (19) at its from the

Drum cover side facing away no longer extending gutter element (29) but only the material recess (27), the side walls (31 a, 31 b) are not axially aligned but inclined to the direction of rotation (U) or bent to such or the outgoing flow something or wholly to deflect in the direction of rotation, so that the weir plates have a grooved shape.

10. A solid bowl centrifuge according to one of the preceding claims, characterized in that the liquid outlet of the discharge channel (25) is inclined relative to the rotational direction (U) by an angle γ.

1 1. Solid shell screw centrifuge according to one of the preceding claims, characterized in that the following applies to the angle γ: γ> = 0 ° and γ <90 °.

12. Solid bowl centrifuge according to one of the preceding claims, characterized in that for the angle γ: γ <0 °.

13, solid bowl screw centrifuge according to one of the preceding claims, characterized in that the bottom wall (35, 35 ') of the discharge channel (25) has a total over its length or sections a rounded, in particular concentric to the center of rotation running mold.

14. A solid bowl centrifuge according to one of the preceding claims or according to the preamble of claim 1, characterized in that the drum cover (17) has one or more passage openings (15), each with respect to the longitudinal axis (D) of the drum (1) an angle δ is inclined / is aligned, which is at least partially or preferably continuously greater than 0 ° and less than 90 ° and for the particular applies: δ> = 20 ° and δ <= 60 °.

15. Solid bowl screw centrifuge according to claim 14, characterized

characterized in that each of the inclined passage openings (15) is partially covered by a corresponding weir plate (19).

16. A solid bowl centrifuge according to one of the preceding claims, characterized in that in the one or more

Through openings (15) in each case an insert (41) is inserted, whose inner contour is aligned inclined relative to the axis of rotation (D) of the drum by an angle δ.

17, solid bowl screw centrifuge according to one of the preceding claims, characterized in that the angle δ at least partially or preferably continuously greater than 0 ° and smaller than 90 °, and that preferably applies: δ> = 20 ° and δ <= 60 ° ,

18. Solid bowl screw centrifuge according to one of the preceding claims, characterized in that the angle δ is equal to the angle ß.