EP1507922A1

EP1507922A1 - Bar screen device

Info

Publication number: EP1507922A1
Application number: EP03722531A
Authority: EP
Inventors: Thomas Mickelat
Original assignee: Andritz Fiedler GmbH
Current assignee: Andritz Fiedler GmbH
Priority date: 2002-04-24
Filing date: 2003-04-23
Publication date: 2005-02-23
Also published as: CA2480294A1; US20050224199A1; WO2003091496A1; DE10218323A1

Abstract

The invention relates to a bar screen device (1, 1', 1''), especially for treating fibrous suspensions in the paper industry. Said device comprises a plurality of bars (2, 2', 2", 2" ) which are fixed to at least one reinforcing element (3, 3', 3", 3" ) in such a way that they extend parallel at a pre-determined mutual distance which is defined by spacer elements (4*, 4*', 4*", 4*" ), the mutual distance between the same defining the width of the slits in the bar screen device. The spacer elements (4*, 4*', 4*", 4*" ) are also embodied as connecting elements (4, 4', 4", 4" ), especially in order to avoid notch-induced resistance variations, and fix the bars (2, 2', 2", 2" ) to the reinforcing elements (3, 3', 3", 3" ) in such a way that they are distanced, in all three dimensions, in a positively and force locking manner, from the base of the bars to as close as possible to the neutral fibres of the bars (2, 2'; 2", 2" ) impinged upon. In this way, the bars can be fixed to the reinforcing elements without welding, and the separated, spatially positively locking connections between the bars (2, 2', 2", 2" ) and the combined spacer and connecting elements (4*, 4*', 4*", 4*" ), and between the combined spacer and connecting elements (4, 4', 4", 4" ) and the reinforcing elements (3, 3', 3", 3" ), are largely free of any notch effect, such that the component resistance remains unlimited.

Description

Spaltsiebvorrichtung

description

The invention relates to a slotted screen device, which is intended in particular for the treatment of fiber suspensions for the paper industry and has the features of the preamble of claim 1.

In the older, not prepublished German patent application 100 52 715.9 from October 24, 200, a pluggable slotted screen arrangement is proposed, which comprises a plurality of rods fixed in parallel on at least one reinforcing element at a predetermined mutual distance by means of spacer elements. The mutual spacing of these rods determines the gap width of the slotted screen arrangement. In this pluggable slotted screen arrangement, the bars form a positive connection with the reinforcing element, which can be designed, for example, as a reinforcing ring or retaining ring, or with the spacer element. The spacer elements can be designed as individual, separate elements or combined to form a one-piece spacer comb.

With this slotted screen arrangement, it has been shown that the direct positive and non-positive connection of the bars to the reinforcing elements is associated with a reduced service life of the screening device due to the induced notches on the bars. It also required the necessary, tight coordinated tolerances of the bars with the reinforcing elements increased manufacturing and assembly costs. With this slotted screen arrangement it has been shown that the direct positive and non-positive connection of the bars with the reinforcing elements or the spacing elements can impair the service life of the slotted screen assembly due to the induced notch effect on the bars. The necessary, closely coordinated tolerance of the bars and the reinforcing elements necessitate increased production and assembly costs.

A slotted screen device is known from EP 0 929 714 B1, in which the parallel profile bars are inserted into slotted, U-shaped, reinforcement rings and are positively fixed in the reinforcement ring in the foot region by local deformation. The plastic deformation creates a notch and reduces the resilience and / or the service life of the profile bars.

A screening device is known from EP 0 417 408 B1, which comprises profiled bars and reinforcing rings provided with groove-shaped recesses. A larger groove width is provided in the groove base in order to enclose the thicker profile wire base, which is complementary in cross section, in a force-fitting and form-fitting manner. According to this, a broader profile wire base must be formed across the entire profile wire extension, as seen in cross section, which leads to unfavorable aerodynamic conditions.

EP 0 499 154 B1 describes a screening device comprising the basic elements, namely profile bars and reinforcing rings. The profile wires are positively connected to the reinforcement rings by a snap lock. Here, too, the groove-shaped recesses induce notch effects in the reinforcing ring that tire the component. The invention therefore aims at overcoming the above-described disadvantages of the prior art to provide a slotted screen device in which the connection between the bars and reinforcing elements takes place largely without notch-induced strength weakening, and which can be produced flexibly, inexpensively.

According to the invention, a slotted screen device is provided for this purpose, the features of which are specified in patent claim 1.

Further advantageous embodiments are listed in claims 2 to 11.

In the slotted screen device according to the invention, a spacer element with an integrated connecting element is provided, which essentially fulfills three different tasks. First of all, the connecting element serves to set the predetermined gap width of the slotted sieve device, in that it lies flat against the respectively facing rod foot flanks and thus arranges them at a predetermined distance from one another. Furthermore, the connecting element increases the component strength of the rod by providing a positive connection as close as possible to the neutral fiber of the rod which is subjected to bending (stress). As a result, the support reaction is not introduced into the zone of the highest load on the rod, either in the rod head or in the rod base, but in less stressed areas of the rod. Third, the connecting element forms a non-positive and positive snap connection between the combined spacer and connecting element and the reinforcing element, so that the reinforcing element also has no weakening notches in transverse extension, and early component failure is minimized. Overall, flexible and cost-effective production is also achieved. According to a further embodiment of the invention, the connecting elements which are positively connected to the rods form a form-fitting connection with the reinforcing elements. This type of connection allows simple and inexpensive installation. Because the connecting elements are always designed in the same way, a reduction in storage for reinforcing elements with different dimensions can be achieved.

A hole-shaped recesses or a peg-shaped projection is preferably provided on at least one end face facing the rod in order to form the positive connection. In both cases these face the rod flow flanks and can be symmetrical, e.g. Include cylinders, ellipses or asymmetrical shapes of recesses or projections. The same applies to the complementary recesses or projections in the side of the rod base. As a result of the pressing of the projection and a recess complementary thereto, a positive connection is formed, which is able to absorb the forces from all three spatial directions.

In order to make the flow resistance of the slotted screen arrangement as low as possible and to avoid fiber buildup in the operating state, the connecting element on its side facing the fiber suspension is designed to be streamlined, for example rounded off accordingly.

Furthermore, the connecting element on its surfaces facing the reinforcing element is seamlessly adapted to the contour of the reinforcing element.

According to a further embodiment, the slotted screen device is designed as a slotted screen cylinder or slotted screen basket, and the reinforcing element as a reinforcing ring for receiving the radial loads. The In the connecting element provided in the invention, the gap width or slot width of such a wedge wire cylinder is then reliably determined in cooperation with the rod foot width and the force reactions of the support reactions take place near the neutral fiber of the rods.

To simplify the manufacture and the reduction of the assembly components, several connecting elements can be combined in the form of a coherent connecting element chain, which in turn can also comprise one or more connecting element segments.

The connecting elements can be applied to a thin connecting wire with a welding joining process, for example resistance welding, roughly spaced apart in order to reduce the number of small parts as a whole and to rule out the source of errors when installing individual connecting elements with a different thickness tolerance. In addition, segmentation of the chain length gives a length that is suitable for assembly.

The reinforcing elements can preferably be prefabricated as rings and additionally secured by a positive connection with a snap lock. This allows greater process reliability when joining and assembling the reinforcement rings and therefore also allows a greater fully automated vertical range of manufacture.

According to an alternative embodiment of a slotted screen device according to the invention, the form-fitting connection of the combined spacer and connecting element and rod is formed in situ, complementary parts on the rod and on the combined spacing and connecting element being impressed directly in place by a corresponding bending , In summary, it is essential in the slotted screen device according to the invention that the design is such that the rods are positively fixed in all three spatial directions without restricting their inherent stability. This is essentially achieved in that the positive connection between the rods and connecting elements combined with the spacer elements is arranged in the immediate vicinity of the neutral fiber of the respective bending rod. Furthermore, the form-fitting connection of rod and combination of spacer and connecting element is separated from the form-fitting connection of the same with the reinforcing element, and both are expediently designed to be as free of notches as possible. Thus, the slotted screen device according to the invention can be produced inexpensively, without a material connection of the connecting elements and the rods, and it is possible to avoid intrinsically harmful welding stresses in the rods.

The invention is explained below with reference to preferred embodiments with reference to the accompanying drawings.

It shows:

1 shows a perspective detail view to illustrate the essential components of a first preferred embodiment of a screening device according to the invention;

2 shows a perspective cutout view of the

Screening device according to Figure 1 without reinforcing element

3a and 3b each show individual parts of examples of connecting elements; 4a to 4c each show schematic assembly representations of design variants of a form-fit connection between the connecting element and the rod, viewed in cross section to the rod;

5a and 5b each show schematic assembly representations of cross-sections to the reinforcing element of embodiment variants of a form-fitting connection between the connecting element and the rod and the reinforcing element;

6 shows a perspective cutout view of another

Embodiment variant of a slotted screen device according to the invention;

7a and 7b are schematic views to illustrate a further embodiment of a slotted screen device according to the invention.

In the figures of the drawing, identical or similar parts are denoted by the same reference numerals and only a few embodiments and exemplary embodiments are illustrated without any restrictive character.

FIG. 1 shows schematically in a perspective view an embodiment of a slotted screen device 1 which can be used for the treatment of fiber suspensions in the paper industry, in particular for sorting. The slotted sieve device 1 comprises rods 2 running in the longitudinal direction, only a partial section of a rod 2 being shown in FIG. 1 for clarification. With the aid of a spacer element designated by 4 ^* , which is combined with a connecting element, the parallel rods 2 are spaced apart, so that sieve slots are formed between the adjacent rods 2. Furthermore, the slotted sieve device 1 comprises a plurality of regularly spaced reinforcing elements 3 oriented orthogonally to the longitudinal direction of the rods 2 for receiving the static and dynamic loading of the sieving device 1. In FIG. 1, only a partial section of the reinforcing element 3 is shown to improve the overview. The positive and non-positive connection of the bars 2 with the reinforcing elements 3 is carried out by means of the connecting element 4, which is arranged spatially in between. The connecting element 4 positions a (here concealed) arranged projection in a complementary recess 5 in the rod foot region 11 and thus establishes a positive connection between the rods 2 and the connecting elements 4. The structural details of the form-fitting connection are shown in more detail in FIGS. 3a and 3b, as well as FIGS. 4a, 4b and 4c, and are then explained in more detail there.

The connection of the reinforcing elements 3 to the connecting elements 4 shown in FIG. 1 is achieved by positive locking, by positioning the T-shaped guide of the reinforcing element 3 in a complementary T-shaped recess in the connecting element 4. FIG. 2 shows a sketch of a section of the slotted screen device according to the invention without a reinforcing element 3 in order to show the complementary configuration of the recess without being covered by the reinforcing element 3.

The recesses are not limited to T-shaped contours, they can of course also have teardrop-shaped or polygonal contours. Different configurations of connecting elements 4 and 4 ^'are shown on the basis of FIGS. 3a to 3b and are described below.

The connecting element 4 shown in Figure 3a is illustrated in more detail as a perspective drawing of individual parts. The connecting element 4 shown here is divided into an area which faces the rod foot area 11 and a further area which faces the reinforcing element 3. The area with the bar foot assignment forms the distance function of the connecting element 4 in connection with the bar foot width. Depending on the desired slotted screen width of the slotted screen device 1, the thickness D of the connecting element 4 is selected from an assortment of different thicknesses or is produced by machining the end face 12 of the connecting element 4. In FIG. 3a, a cylindrical pin is formed orthogonally to the end face 12 * as a projection 8 as a partial element for producing the positive connection. The spatial position of the pin within the end face 12 * is defined as the point of the axis of symmetry of the connecting element 4 and the height H, the height H being defined as the distance between the beginning of the rod foot and the height H of the neutral fiber of the loaded rods 2.

The area of the connecting elements 4, which faces the reinforcing elements 3, has a width B which is slightly smaller than the distance between two adjacent bars 2. As a further embodiment variant, the connecting elements 4 can be designed as a link of a connecting element chain 9. Then the originally isolated connecting elements 4 are evenly spaced and oriented in the same way and applied to a wire 10 and preferably connected to it in a materially bonded manner. As a result, the connecting elements 4 are spatially ordered and oriented and the handling of the connecting elements 4 and their assembly with the bars 2 are facilitated. FIG. 3b shows an alternative embodiment of a connecting element Ab. The transfer of T-shaped recess in the reinforcing member 3 with a continuous uniform thickness D on the end faces 12 and 12 ^', the connecting element 4 is ^now' * to produce. Since this embodiment does not require a subdivision into two regions of different thicknesses, the production of the connecting element is simpler and therefore less expensive. When the connecting element chain 9 is formed, the connecting elements 4 ^'are also uniformly spaced apart and fixed in the same way on the wire 10 ^" on the T-shaped guide region of the positive-locking connection. The connecting element chain 9' thus has comparable advantageous properties to the embodiment described in FIG. 3a ,

FIGS. 4a to 4c show cross-sectional representations of the different types of interlocking connections between rod 2 and connecting element 4 in a slotted screen device according to the invention. FIG. 4a shows the embodiment variant already described with a continuous, hole-shaped recess 5 in the rod foot region 11 of the rods 2. As a complementary configuration of the connecting elements 4, cylindrical pins are formed as projections 8 on the end faces 12 * of the connecting elements 4. The height of the cylindrical pins 8 is necessarily less than the bar foot width of the bars 2, so that the distance-generating end faces 12 and 12 * and the bar foot regions 11 can lie flat.

FIG. 4b shows a cross-section of a rod with a recess 5 ~ which is designed as a conical countersink in the rod foot region 11 ^* . This recess 5 can be created by a forming process. The recess 5 ^' is preferably formed using a machining production process, for example using a twist drill. The advantage of the design of the projection 5 ^' is the smaller one Notch effect of the recess 5 ^' and the lifespan extension of the rods 2 which can be achieved thereby. The complementary configuration of the projections 8' of the connecting elements 4 ^' is designed as a blunt rotary cone. 4b, this conical projection 8 'is shown as an obtuse triangle. Disc-shaped, prism-shaped or other geometrical configurations, for example, come into consideration as other configurations of the projections 8 and 8 ^' and the complementary recesses 5 and 5 ^' , which are not shown here.

A further variant of the positive connection is shown in FIG. 4c. The protrusion 6 is now provided on the rod foot region 11 of the rod 2 ^" . The protrusion 6 can be produced, for example, by an embossing process which reforms the rod foot region. The complementary recess 7 of the connecting element 4"'is designed here as a distance-generating ring element which protrudes the protrusion 6 of the Includes bar 2 comprehensively.

FIGS. 5a to 5b schematically show the form-fitting interaction of the connecting elements 4 and 4 ^' and the reinforcing elements 3 and 3 ^' .

FIG. 5a shows the mode of action of the positive snap connection between a connecting element 4 and a reinforcing element 3 of the slotted screen device according to the invention according to FIG. 1. In the illustration on the left, the reinforcing element 3 is positioned under the connecting element 4 such that the guide of the reinforcing element 13 into a T- shaped recess of the connecting element 4 protrudes. During assembly, the guide of the reinforcing element 13 is now pressed into the recess, so that the elastically deformable flanks 14 and 15 of the connecting element 4 deflect in the direction of the longitudinal extension of the bars 2. Is the guidance of the reinforcing element 13 completely surrounded by the recess of the connecting element 4, the flanks 14 and 15 of the connecting element 4 spring back.

FIG. 5b shows an alternative positive snap connection between a connecting element 4 and a reinforcing element 3 '.

In this embodiment, the resilient flanks 17 and 18 are formed in the reinforcing element 3 ^' and, in addition to this, the connecting element Ab is provided with a T-shaped guide 16. The operating principle of this positive snap connection is analogous to the embodiment shown in FIG. 5a.

FIG. 6 schematically illustrates a variant embodiment of a slotted screen device 1 ^' in a perspective view. Here is a connecting element chain 9 ", with the mechanism of action of the positive connection between connecting ^element 4 ^{", Λ} and rod 2 "according to FIG. 4c, which does not comprise individual links, but has a comb-like shape.

The connecting element chain 9 "according to FIG. 6 can be constructed by integrally joining a tube, which serves to hold the rods 2, and a trough-shaped flat wire, which serves to hold the reinforcing elements 3. The tubular area is machined with a slit-shaped, The hole-shaped recesses 7 of the connecting element chain 9 ^" encompass the projections 6 of the rods 2 ^" hidden here and form a positive connection.

According to a preferred embodiment, the slotted screen device 1 ^{'is designed} as a slotted screen cylinder. To accommodate the inside of the strainer basket annular reinforcing elements are then inserted ^"in the circumferential direction in the trough-shaped region of the connecting element chain ^9" 3 outwards acting radial forces. The trough-shaped or C-shaped receptacle of the connecting element chains 9 ^″ form a positive connection with the ring-shaped reinforcing elements 3 ″, which does not require a snap-lock mechanism as shown in FIGS. 5a and 5b. In addition, the trough-shaped design ensures that the fiber suspensions are discharged in a streamlined and streamlined manner during operation.

FIGS. 7a and 7b show a further slotted screen device 1 ^" with a comb-like design of the connecting element chain 9" \ Here, as already shown in FIG. 6, it is not a closed tubular area for receiving the rods 2 ^'" , but a cross section for the longitudinal extension of the connecting element chain 9 ^'" , loop-shaped sheet metal element used to generate the distance function. This thin-walled sheet metal element is integrally connected to the rod-shaped reinforcing element 3 ^'" to form a unit. Subsequently, rods 2 ^" \ which are designed without recesses δ.δ ^' or projections 6 are inserted into the recess of the loop-shaped connecting element chain 9 ^"" If the bars are located radially on the inside, the slot-shaped recesses are narrowed by the spacing-producing web areas reducing bending radius largely retained in shape, press evenly into the rod base regions 11 of the rods 2 ^"" and thereby form local recesses and projections on the rod base regions nd projections on the rod foot areas in itself then form the positive connection of rod 2 ^" 'and connecting element chain 9 ^" '. Although not shown in more detail, combinations of the previously explained embodiments of connecting elements 4 to 4 " ^* and different reinforcing elements 3 to 3 '" can of course also be realized in a slotted sieve device 1, 1', 1 ", 1 '". The invention is therefore not limited to the details of the slotted screen devices 1 to 1 "explained and described above, but numerous changes and modifications are possible which the person skilled in the art will make if necessary without departing from the inventive concept. Of course, the slotted screen device 1 also needs 1 ', 1 ", 1'" not to be designed as a flat slotted screen mat, but it can also be designed as a slotted screen cylinder or as an arcuately curved slotted screen mat, for example.

Spaltsiebvorrichtung

List of signs

Slotted screen device in total

2.2 ^' , 2 ^" , 2 ^"' rod

3.3 ^' , 3 ", 3 ^'" reinforcing element

4,4 ^' , 4 ^' \ 4 ^'" connecting element

4 * _ι 4 * 4 * ^" _ι 4 * '" spacer

5.5 ^' recess in the rod

6 tab of the bar

7 recess of the connecting element

8,8 ^' , 8 "projection of the connecting element

9.9 ^' , 9 ^" , 9 ^'" connector chain

10 wire

11 pole base area

12 end face of the connecting element

13 guidance of the reinforcing element

14, 15 snap closure of the

connecting element

16 guidance of the connecting element

17, 18 snap lock of the

reinforcing element

D distance generating thickness of the

Connecting element 4, 4 ', 4 ", 4'"

B width

H altitude of the neutral fiber of the Sta

2, 2 ', 2 ", 2"

Claims

claims

1. Slit screen device (1.1 \ 1 ", 1"^' ), in particular for the treatment of

Fiber suspensions in the paper industry, which a plurality of parallel to at least one reinforcing element (3,3 ', 3 ", 3 ^' ") at a predetermined mutual distance by means of spacers (4 *, 4 * \ 4 * ", 4 * '") , fixed rods (2,2 \ 2 ^" , 2 ^'" ), the mutual spacing of which determines the gap width of the slotted screen device, characterized in that the spacer elements (4 *, 4 * \ 4 ^{* "} , 4 ^* "^' ) also serve as connecting elements (4,4 \ 4 ^" , 4 ^"' ) are formed which form-fit the rods (2,2', 2 ^' \ 2 "') in all three spatial directions, spaced from the rod foot region (11, 11 ', 11", 11 '") in the direction as close as possible to the neutral fiber of the loaded bars (2,2 ^' , 2 ^" , 2 ^'" ), with force transfer to the reinforcing elements (4,4 \ 4", 4 "^' ).

2. Slotted sieve device (1,1 \ 1 ^" , 1 ^" ) according to claim 1, characterized in that the connecting elements (4,4 \ 4 ^" , 4 ^' ") have a positive connection with the reinforcing elements (3,3 ^' , 3 ^" , 3 ^'" ) form orthogonal to the longitudinal extension of the rods (2,2', 2 ^" , 2 ^' ").

3. slotted screen device (1,1 ^' , 1 ", 1 ^'" ) according to claim 1 or 2, characterized in that the respectively predeterminable, variable gap width in cooperation of the foot width of the rods (2,2 ^' , 2 ^" , 2 ^'" ) and the connecting elements (4,4 ^' , 4 ", 4 ^'" ) is determined.

4. Slotted screen device (1, 1 ^' , 1 ^" , 1 ^'" ) according to one of the preceding claims, characterized in that to form the positive connection of the rod foot region (11, 11 ', 11 ", 11"') spaced apart on the rods (2.2 \ 2 ^" , 2 ^'" ) a recess (5.5', 5 \ 5 '") or a projection (6.6 ^' , 6 ^" , 6 ^"* ) is formed, and that the connecting elements ( 4,4 ^' , 4 ^" , 4 ^'" ) recesses (7,7 ^' , 7 ^" , 7 ^"' ) or projections (8,8 ^' , 8 ^" , 8 ^'" ) of complementary design on the rods (2nd , 2 ', 2 ", 2"') facing end face of the connecting elements (4, 4 ', 4 ", 4'").

5. Slotted sieve device (1, r, 1 ^" , 1 '^" ) according to one of the preceding claims, characterized in that the connecting element (4 _ι 4 ^, _ι 4 ", 4"') is designed aerodynamically on its flow-facing outer contour.

6. Slotted screen device (1, 1 ^' , 1 ^" , ^" ) according to one of the preceding claims, characterized in that the connecting element (4 _ι 4 4 " _ι 4 ^,>" ) on its the reinforcing element (3,3 ^' , 3 ^" , 3 ^'" ) facing surfaces is seamlessly adapted to the contour of the reinforcing element (3,3 ^' , 3 ^" , 3 ^' ").

7. Slotted sieve device (1,1 ^* , 1 ^" , 1 ^'" ) according to one of the preceding claims, characterized in that the sieve device (1,1', 1 ", 1 '") as a rotationally symmetrical sieve cylinder and the reinforcing element (3,3 ^' , 3 ^" , 3'^" ) is designed as a reinforcing ring for receiving radial loads.

8. Slotted screen device (1, 1 ^' , 1 ^" , 1'^" ) according to one of the preceding claims, characterized in that the connecting elements (4 _ι 4 4 " _ι 4 ^, ) in the form of a one-piece connecting element chain (9.9 \ 9" , 9 "') are formed, which comprises one or more connecting elements (4,4 ^' , 4 ^" , 4 ^'" ).

9. slotted screen device (1,1 ^' , 1 ", 1 ^'" ) according to one of the preceding claims, characterized in that the connecting elements (4,4 ^' , 4 ^" , 4 ^'" ) or the connecting element chain (9,9 ', 9th ", 9"') is or are positively connected to at least one reinforcing element (3,3', 3 ", 3 '").

10. Slotted screen device (1,1 ^' , 1 ", 1 ^' ") according to claim 10, characterized in that the positive connection is designed as a snap connection.

11. Slotted screen device (1, 1 ', 1 ", 1'") according to claim 1, characterized in that the spacer elements (4 *, 4 * ', 4 * ", 4 *"') with the respective reinforcing element (3, 3 ', 3 ", 3'") are firmly connected, and the connecting elements (4, 4 ', 4 ", 4'") with the positive connection with the rods (2, "', 2", 2 "') by bending the fixed spacer elements (4 ^* , 4 * ', 4 * ", 4 *"') connected to the respective reinforcing element (3, 3 ', 3 ", 3'") are formed in situ.