DE102004019368B4 - Weighing device for a centrifuge - Google Patents

Abstract

military equipment for one Centrifuge (10) with a centrifuge drum rotating about a centrifuge axis (14) (12), in particular for a solid bowl centrifuge in which a clarified liquid through at least one drain opening (36) discharged from the interior of the centrifuge drum (12) to the outside and at the for adjusting the pond depth within the centrifuge drum (12) the size of at least a drain opening (36) from outside the centrifuge drum (12) is changeable forth, characterized that at the at least one drain opening (36) a first and a second weir element (38, 40) are provided which are axially adjacent to each other are arranged in such a way that clarified liquid can be conveyed via both defense elements (38, 40) flows out, and of which the first weir element (38) with the centrifuge drum (12) co-rotating and the second weir element (40) not with the centrifuge drum (12) co-rotating and at least partially radially adjustable is designed.

Description

Background of the invention

The The invention relates to a weir for a centrifuge with a Centrifuge drum rotating about a centrifuge axis, in particular for one Solid bowl screw centrifuge, in which a clarified liquid by at least one drain hole from the interior of the centrifuge drum is discharged to the outside and at for adjusting the pond depth within the centrifuge drum the size of the at least a drain opening from outside the centrifuge drum ago changeable is. Furthermore, the invention relates to a centrifuge, in particular a solid bowl screw centrifuge, with such a Wehrreinrichtung.

at Centrifuges forms during of operation under the action of centrifugal force within the centrifuge drum a liquid ring whose inner diameter from the arrangement of weir plates it is determined which, on the circumference of a drum end wall before drain openings are arranged. By adjusting the weir discs, the liquid level or the pond depth can be changed in the centrifuge drum. Changing The pond depth should in particular also during operation of a centrifuge possible be, for which in the prior art already proposed numerous Wehreinrichtungen have been.

Out DE 39 21 327 A1 a weir is known, which consists of elements such as flaps, sliders, wedges, etc., which are arranged in the region of the distributed at the drum end wall drain holes and which rotate with the drum. The co-rotating adjusting elements are in operative connection via mechanical connecting elements with a non-co-rotating adjusting device. Because this connection between co-rotating adjusting elements and non-co-rotating adjusting device is comparatively complex, such weir systems have not prevailed.

Out DE 43 20 265 C2 is a Vollmantelschneckenzentrifuge with an adjustable weir for the course of a liquid phase, in which outside the drum opposite drain holes a stationary, but axially displaceable throttle disc is arranged. The free cross-sectional area between the co-rotating with the centrifuge drum discharge openings and the axially parallel and plane-parallel slidable throttle disc determines the outflow cross section for the liquid and thus their level or pond depth in the drum. The disadvantage is that the device for axis-parallel guidance and displacement of the plane-parallel to the drum end wall stationary throttle plate is not arranged outside of the wet and dirty part of the centrifuge.

Out EP 1 280 606 B1 a solid bowl centrifuge is known in which an adjustable weir consists of a connected to a centrifuge housing and the outlet openings of the centrifuge drum from the outside at a distance covering fixed, ie not co-rotating ring cup having at least one adjustable by an adjustment in its size passage opening at its ring circumference, through which the liquid can escape into a liquid collecting chamber of the centrifuge housing. Also, such a Wehrreinrichtung is relatively complex and there is an increased risk of the non-co-rotating ring cup that the variable passage openings are blocked by leaking material.

Underlying task

Of the Invention is based on the object, a centrifuge with a to provide simply built adjustable weir, with the pond depth within the centrifuge drum reliable and with low energy consumption during operation of the centrifuge changed can be.

Inventive solution

These Task is according to the invention with a dissolved at the beginning of the aforementioned Wehrreinrichtung, at the at least a drain opening a first and a second weir element are provided which are axially are arranged side by side so that clarified liquid flows through both weir elements, and of which the first weir element coincides with the centrifuge drum and the second weir element not co-rotating with the centrifuge drum and at least partially radially adjustable is designed. Furthermore, the object is with a centrifuge, in particular a Vollmantelschneckenzentrifuge, solved with such a Wehreinrichtung is provided.

In the centrifuge according to the invention, the liquid ring located in the centrifuge drum on the drum end wall is delimited by a first weir element, which rotates with the centrifuge drum. As a rule, the first weir element determines the minimum height of the liquid within the centrifuge drum that can be set during operation. According to the invention, this first weir element is assigned a second weir element, which does not rotate with the centrifuge drum and is arranged next to the first weir element. This second weir element is used for the precise setting and adjustment of the pond depth within the centrifuge drum even during operation of the centrifuge. The effluent clarified liquid thus flows over both defense elements. The second Wehrele ment is at least partially radially adjustable, whereby the distance between the drum wall and an overflow edge of the second weir element is changed at the at least one drain opening. When changing the distance more or less clarified liquid flows out of the centrifuge drum and it accordingly changes the pond depth within the centrifuge drum.

Of the significant difference of the invention over the prior art also in that the effective or final pond depth through a Wehrelement is determined, which is covered by clarified liquid, but still not rotates with the centrifuge drum. Furthermore, this is not co-rotating Weir element adjusted in a plane perpendicular to the centrifuge axis, including only comparatively simple adjusting devices are needed. The adjustment can about that outside outside the wet and dirty part of the centrifuge are arranged.

Finally lies a significant advantage of the centrifuge according to the invention is that with the weir according to the invention also large drainage holes be changed in size can and / or discharge or trailing edges with a comparatively large overflow area (i.e. a large overflow height and / or a large overflow width) can be provided so that larger floating Particles can be washed out of the centrifuge drum. Such comparatively large Outflow openings or outflow cross have the further advantage that the centrifuge when parking and upon collapse of the circulating liquid ring at smaller Speed a rapid and largely complete emptying is possible. This also applies to operating phases of a centrifuge where e.g. for cleaning purposes aware of a speed just below the limit to training one liquid cylinder is controlled.

The Flooding of particles is therefore particularly facilitated because the particles with appropriate design not through a gap or slit must emerge, as is partially required in the prior art. at the Wehrein direction according to the invention can therefore e.g. even relatively large particles are flushed out, on the liquid in the centrifuge drum float. Furthermore, in the device according to the invention, the outlet region the liquid at the second weir element comparatively easily to a partial area the drum circumference are limited. With this limitation results There is a comparatively large overflow height of the liquid on the second defense element. Be inside the highly overflowing liquid also great Particles that float in the liquid, washed out of the centrifuge drum.

Advantageous developments the invention

at an advantageous development of the invention Wehreinrichtung the second weir element is designed rotatable and twisting will be at least a section of the second defense element, which is before the at least one drain opening is located, radially adjusted. The for adjusting such second military element required rotational movement can be cost-effective and be operated safely with an adjustment, which Having around the centrifuge axis rotatable elements. By accordingly simple lever mechanisms can at high adjusting forces short adjustment paths are provided.

A particularly simple and yet precisely adjustable weeding device results from the second weir element designed with an eccentric disc is, which is mounted eccentrically to the centrifuge axis. By twisting such a mounted eccentric disk is that particular section the second weir element, which is located in front of the at least one drain opening, radially inwards or outwards adjusted.

at another, particularly easy to be designed adjusting for the second weir element is this pivotally mounted and pivoting will be at least a section of the second defense element, which is before the at least one drain opening is located, radially adjusted.

One Such pivotable second weir element can be very cost effective be mounted a pivot arm, which is about one of the centrifuge axis staggered pivot axis is pivotable. The pivoting movement can then by electromagnetic, hydraulic or purely mechanical Adjustment mechanisms are effected.

at a further relatively inexpensive to implement inventive Wehrreinrichtung the second weir element is displaceable relative to the first weir element and when moving at least a portion of the second weir element, which is located in front of the at least one drain opening, radially adjusted.

The second weir element can in such a Wehreinrichtung means a simple, radially movable slide be realized.

Alternatively or additionally, it is advantageous if the second weir element is designed with an annular disc, in particular in front of a plurality of Drain holes is mounted adjustable. A radial adjustment of such an annular disk results in a "free" overflow area not covered by the non-co-rotating annular disk relative to the circulating weir element or the associated drainage openings, because this overflow area limits only part of the circumference of the non-co-rotating weir element or annular disk is, results in the overflow edge a comparatively large overflow height, whereby a floating out of larger floating particles is supported out of the centrifuge drum out.

As already mentioned, The core of the invention is, inter alia, that at least a portion of the non-co-rotating second weir element before at least one drain hole is adjustable perpendicular to the rotor axis. If the second defense element designed as an annular disc, this is eccentric when adjusting or moved perpendicular to the centrifuge axis. Independent of the path of the shift always gives the desired function a limited overflow area on the circumference of this washer.

at the Wehrreinrichtung invention can between the first and the second weir element an annular gap be formed, through which a small part (leakage) liquid can flow out of the interior of the centrifuge drum. The annular gap can targeted adjusted to a certain minimum width or adjusted be assured so is that while the operation of the centrifuge according to the invention excluded is that the first and the second Wehrreinrichtung in solid state contact come.

The first weir element can also be designed with recesses, through the clarified liquid flow out can, while the remaining areas of the first weir element an outflow of liquid outside prevent the recesses. In this way, the outflow of Liquid over that first defense element on certain sections or areas the drum circumference are limited. With the limited outflow is also the flow of (leakage) liquid limited by the above-mentioned annular gap locally and quantitatively. This reduces the friction of the exiting through the annular gap Liquid.

Brief description of the drawings

following becomes an embodiment of a Inventive device according to the invention with the attached Schematic drawings explained in more detail. It shows:

1 a partial longitudinal section of a centrifuge according to the invention with the weir device in a first position of an associated adjustable weir element,

2 the section II-II in 1 .

3 the partial longitudinal section according to 1 in a second position of the associated adjustable weir element,

4 the section IV-IV in 3 .

5 a partial longitudinal section and two side views of embodiments of first weir elements,

6 a partial longitudinal section and a side view of another embodiment of a first weir element,

7 Side views of two further embodiments of first weir elements and

8th a side view of another embodiment of a first weir element.

Detailed description of the embodiment

In the 1 to 4 is a centrifuge 10 in the form of a solid bowl screw centrifuge, with a centrifuge drum 12 which are in operation of the centrifuge 10 around a centrifuge axis 14 rotated at high speed. In the centrifuge drum 12 there is a centrifuge screw 16 , which also correspond to the centrifuge axis 14 is aligned. The centrifuge screw 16 is with her snail hub on a worm bearing 18 rotatably mounted, which on a drum hub 20 the centrifuge drum 12 is supported. The drum hub 20 is in turn from a drum warehouse 22 supported in a bearing block 24 arranged and in this way on a stationary machine bed 26 is supported.

Through the bearing block 24 through is an inlet pipe 28 inside the centrifuge drum 12 and also inside the screw hub of the centrifuge screw 16 guided. Through this inlet pipe 28 may be a medium to be separated in the centrifuge drum 12 are introduced, which then when rotating the centrifuge drum 12 exposed to high centrifugal forces and attached to a drum wall 30 the centrifuge drum 12 in the form of a liquid ring 32 accumulates. Inside the liquid ring 32 A comparatively solid phase is deposited radially outward, while a comparatively liquid phase or clarified liquid accumulates radially inwards.

For discharging this clarified liquid are on a drum front wall 34 the centrifuge drum 12 a total of six drainage holes are distributed over their circumference 36 educated. The drainage holes 36 are partly from a first defense element 38 covered in the form of an annular disc, the outside of the drum end wall 34 centric to the centrifuge axis 14 is appropriate.

Axial next to the first defense element 38 is a second defense element 40 , which is also designed in the form of an annular disc, but with a smaller inner diameter, provided. This second defense element 40 is about an adjustment 42 on the bearing block 24 attached and therefore does not run with the centrifuge drum 12 around. The first and the second defense element 38 respectively. 40 are arranged relative to each other such that one from the centrifuge drum 12 through the drainage holes 36 effluent, clarified liquid over both weir elements 38 and 40 overflows. It is located between the first defense element 38 and the second weir element 40 a minimum annular gap 44 , by which also at least a small amount of (leakage) liquid from the interior of the centrifuge drum 12 in a drain housing 46 can flow out.

The second defense element 40 is at the adjustment 42 by means of webs 48 on an eccentric disc 50 attached, in turn, on an eccentric hub 52 is rotatably mounted. The bridges 48 hold the second defense element 40 at a distance from the eccentric disc 50 and thus separate the wet and dirty areas of the first and second weir elements 38 respectively. 40 from the remaining Verstelleinrich device 42 , Due to the eccentric bearing of the eccentric disc 50 at the eccentric hub 52 becomes the second weir element designed as an annular disk 40 when turning the eccentric disc 50 either concentric or coaxial or eccentric to the centrifuge axis 14 set. During this movement, individual sections and the inner edge of the second weir element 40 , which in each case viewed in the axial direction in front of the drainage openings 36 located, radially adjusted. By this radial adjustment of the second weir element 40 becomes an overflow edge 54 of the second defense element 40 in front of the associated drainage openings 36 offset radially and in this way the pond depth of the liquid ring 32 inside the centrifuge drum 12 changed.

For turning the eccentric disc 50 is a turn ring 56 provided, which on a fixed ring section 58 next to the eccentric disc 50 is rotatably mounted. At the rotary ring 56 is a radial groove 60 trained in a pen 62 protrudes. The pencil 62 is on the eccentric disc 50 into a hole 64 used so that he turns the turning ring 56 within the radial groove 60 is entrained and by this movement the eccentric disc 50 twisted.

In the 2 and 4 is the adjustment of the second weir element achieved with this rotation 40 relative to the first defense element 38 and relative to the centrifuge axis 14 illustrated again.

2 shows a concentric alignment of the second weir element 40 relative to the centrifuge axis 14 , In this position flows over the entire circumference of the second weir element 40 distributed from all drain holes 36 clarified liquid from the centrifuge drum 12 in the drain housing 46 from.

In 4 is an operating phase of the centrifuge 10 illustrated in which designed as an annular disc second weir element 40 with the help of the eccentric disc 50 and the eccentric hub 52 eccentric to the centrifuge axis 14 is arranged offset. In this position is related to 4 lower area of the second defense element 40 its overflow edge 54 offset radially outwards, whereby the pond depth of the liquid ring 32 in the centrifuge drum 12 is reduced.

In 5 are two embodiments of centrifuge drums 12 illustrates where the first weir element 38 at every drain opening 36 solely by an overflow edge 68 is designed in the drum wall 30 designed itself. The overflow edge 68 limits a minimum diameter 70 that in the centrifuge drum 12 must overcome circulating liquid, so they pass over the first weir element 38 to the second, not shown here defense element 40 can flow. At the in 5 right side view of the weir element 38 or the drum wall 30 it can be seen that the drain opening 36 is designed as a stretched oval, while in the left next to it arranged side view of a drum wall 30 the drain opening 36 has a circular cross-section.

At the in 6 illustrated embodiment is on a drum wall 30 a centrifuge drum 12 a comparatively large, circular discharge opening 36 formed, in front of the outside designed as an annular disc first weir element 38 is appropriate. The first such defense element 38 covers the drain hole 36 partly and with a directed to the drum interior bevel 72 Mistake. The slope 72 ends at an overflow edge 68 , in turn, to be overcome by the liquid minimum diameter 70 Are defined. Because the slope 72 outside the drum wall 30 Liquid can first pass through the circular drain opening 36 emerge and then spread along the slope 72 about one in Comparison to the size of the drain opening 36 wide peripheral region of the designed as an annular disc first weir element 38 , At the defense element 38 according to 6 is also on the side leading to the second, not shown defense element 40 turned, an undercut 74 educated. This undercut 74 causes for the liquid passing through the annular gap 44 between the first and second weir element 38 respectively. 40 flows radially outwards, the flow cross-section increases radially outward. With an enlarged flow cross-section, the flow friction and the braking effect of the liquid (leakage) flowing in this way decrease.

In 7 are two embodiments of first weir elements 38 illustrated, which are each designed as a substantially circular annular disc. While at the in 7 illustrated embodiment on the annular disc and the overflow edge 68 is designed in a circular shape, is in the in 7 right illustrated embodiment of the minimum diameter 70 by means of two recesses 76 limited between two smaller diameter disc sections 78 are formed. With the help of the disc sections 78 is the outflow of liquid through the first weir element 38 away on the two recesses 76 limited, which means that only at these recesses 76 (Leakage) liquid in the annular gap 44 between the first and second weir element 38 respectively. 40 arrives. In addition, by limiting the fluid flows to the recesses 76 achieved a comparatively large overflow height, which leads to the advantages already mentioned above.

8th illustrates an embodiment of a drum wall 30 , at the several first defense elements 38 are arranged in the form of individually adjustable slide. Top right is in 8th a section of such a first defense element 38 shown. The individual slides or first defense elements 38 can at standstill the associated centrifuge 10 be adjusted individually, so that depending on the task different overflow heights or minimum diameter 70 can be adjusted.

10

centrifuge

12

centrifuge drum

14

centrifuge axis

16

centrifuges screw

18

worm bearing

20

drum hub

22

drum bearing

24

bearing block

26

machine bed

28

inlet pipe

30

drum wall

32

liquid ring

34

Drum front wall

36

drain hole

38

first weir member

40

second weir member

42

adjustment

44

annular gap

46

drain body

48

web

50

eccentric

52

eccentric hub

54

overflow edge

56

rotating ring

58

ring section

60

radial groove

62

pen

64

drilling

68

Overflow edge

70

Minimum diameter

72

slope

74

Hinderschneidung

76

recess

78

disk portion

Claims (10)

Weighing device for a centrifuge ( 10 ) with one around a centrifuge axis ( 14 ) rotating centrifuge drum ( 12 ), in particular for a solid bowl screw centrifuge, in which a clarified liquid through at least one drain opening ( 36 ) from inside the centrifuge drum ( 12 ) is discharged to the outside and at the for adjusting the pond depth within the centrifuge drum ( 12 ) the size of the at least one drain opening ( 36 ) from outside the centrifuge drum ( 12 ) is changeable, characterized in that at the at least one drain opening ( 36 ) a first and a second defense element ( 38 . 40 ) are provided, which are arranged axially next to each other such that clarified liquid over both defense elements ( 38 . 40 ), and of which the first weir element ( 38 ) with the centrifuge drum ( 12 ) and the second defense element ( 40 ) not with the centrifuge drum ( 12 ) co-rotating and at least partially radially adjustable. Weeding device according to claim 1, characterized in that the second weir element ( 40 ) is rotatable and at least a portion of the second weir element ( 40 ) located in front of the at least one drain opening ( 36 ) is adjusted radially. Weeding device according to claim 2, characterized in that the second weir element ( 40 ) with an eccentric disc ( 50 ) which is eccentric to the centrifuge axis ( 14 ) is stored. Weeding device according to one of claims 1 to 3, characterized in that the second weir element ( 40 ) is pivotable and at least a portion of the second weir element ( 40 ) located in front of the at least one drain opening ( 36 ) is adjusted radially. Weeding device according to claim 4, characterized in that the second weir element ( 40 ) is designed with a pivoting arm, which is around one of the centrifuge axis ( 14 ) offset pivot axis is pivotable. Weeding device according to one of claims 1 to 5, characterized in that the second weir element ( 40 ) is displaceable and at least a portion of the second weir element ( 40 ) located in front of the at least one drain opening ( 36 ) is adjusted radially. Weeding device according to claim 6, characterized in that the second weir element ( 40 ) is designed with at least one radially movable slide. Weeding device according to one of claims 1 to 7, characterized in that the second weir element ( 40 ) is designed with an annular disc, in front of a plurality of drain holes ( 36 ) is adjustably mounted. Weeding device according to one of claims 1 to 8, characterized in that the second weir element ( 40 ) has a recess with which the discharge of clarified liquid to a certain portion of the circumference of the centrifuge drum ( 12 ) is limited. Centrifuge, in particular solid bowl centrifuge, with a weiring device according to one of claims 1 to 9.