EP0021007A2 - Device for separating cleaning bodies - Google Patents

Abstract

For the self-cleaning of tube heat exchangers, the medium flowing through the tubes (for example cooling water) is mixed with spherical cleaning bodies made of, for example, sponge rubber, the diameter of which is slightly larger than the diameter of the heat exchanger tubes and the contaminants which are deposited on the tube walls are stripped off. Since the cleaning bodies wear out over time, their regular inspection is necessary so that they have to be removed from the heat exchange medium by means of a branching device (10). Such branching devices (10) consist of a cylindrical branch housing (2) which is inserted into the heat exchanger line and has a screen surface (18) arranged at an angle to the flow, which ends at the outflow end in a branch nozzle (4) through which the cleaning bodies (1 ) can be deducted. In the previously used branching devices (10), the risk of cleaning bodies (1) becoming self-locking in throats was countered by relatively complicated designs. The present invention now describes possibilities with which these self-locking effects can be eliminated in a much simpler manner by creating a transition surface in the area between screen surface (18) and housing wall (22) that becomes acute by means of an edge plate (6) or other arrangements that angled throat eliminated. It is also shown that such an edge plate (6) can be used with very different designs for the branching device (10) with the same success.

Description

. The invention relates to a device for branching off discrete cleaning bodies carried in a fluid flowing through a tubular heat exchanger from the main flow of the fluid, consisting of a branch housing through which axial flow flows and a separating sieve device arranged therein with at least one sieve surface arranged obliquely to the flow a branch pipe ends, the screen surface being pivotable for cleaning purposes to such an extent that the screen surface side previously located in the upstream direction comes to lie in the downstream direction.

Such a device is already known from DE-AS 12 27 040. Such devices are used in self-cleaning tubular heat exchangers which work with cleaning bodies which are pressed through the tubes by the medium flowing through the tubes (for example cooling water), in order to strip off the impurities deposited on the walls and thereby keep the heat exchanger constantly cleaned . As the cleaning bodies sponge rubber balls are usually o. The like. Used whose diameter is slightly larger than the diameter of ärmeaustauscherröhren _W. To the Reini To be able to remove the supply body from the heat exchanger liquid again, the device mentioned at the outset is arranged in the outlet line emerging from the heat exchanger, with which device the heat exchanger liquid and cleaning balls are then separated. The cleaning bodies emerging from the branch connector can then, if necessary, be sucked off together with a small part of the heat exchange liquid by means of a return pump and can be returned to the inlet line of the tubular heat exchanger via a connecting line.

The known device consists of a tubular housing with a diameter which corresponds to the diameter of the heat exchanger outlet line. Two screen devices are arranged in this tubular section-like housing, an upper screen device and a lower screen device. The upper sieve device is formed from two sieve surfaces lying at an angle in the flow direction, which approach in the middle of the housing to a kind of funnel opening through which the cleaning bodies are guided into the lower sieve arrangement, while the heat exchange liquid essentially through the openings of the sieves passes through and flows through the cylinder-like housing laminar essentially unhindered. The lower sieve device consists of a box arranged in the middle of the tube housing, which is connected to the horizontal boundary of the upper sieves and in turn consists of lower sieves oriented towards each other in a funnel shape. Both the two upper sieves and the lower sieves are each rotatably mounted in the housing and can be actuated from the outside by backwashing for the purpose of cleaning the sieves. Due to the numerous actuation axes that are required for the various screens, a large number of pipe openings are necessary, which, because they have to be provided with seals, on the one hand make the production costs quite high, and on the other hand increase the need for maintenance of the system. This is especially true in reactor applications where radioactive substances could be carried in the heat exchange medium absolute tightness of the circuit is of particular importance.

Another disadvantage is that the cleaning bodies collect essentially in the center of the cylindrical housing and must first be guided from there to the housing wall before they can exit the housing. In the arrangement shown in FIG. 1 of DE-AS 12 27 040, a branch connector leading radially outwards can cause transportation problems because of the sharp deflection. If the branch connector is placed at an angle in the direction of the current so as not to maintain the sharp kink, the overall length of the device increases. It would therefore be advantageous not to bring the cleaning bodies together in the center of the device, but instead in the vicinity of the outer wall.

Such a solution is shown in DE-PS 26 12 905, in which only an obliquely arranged in the flow direction screen surface is provided, which ends at its downstream end in a branch pipe, which is indeed close to the wall and therefore very easy to remove the cleaning body. This patent also recognizes that the acute angle between screen surface and housing wall which arises in this embodiment can lead to self-locking effects for the cleaning bodies, on the basis of which effects the cleaning bodies can get stuck in spaces tapering to an acute angle. Cleaning bodies that get into such self-locking throats and are held in the throat then usually lead to the subsequent accumulation of further cleaning bodies and the formation of larger piles, which can then make it difficult or completely impossible for the cleaning bodies to be removed, and also impermissibly increase the flow resistance for the exchange liquid .

DE-PS 26 12 905 tries to prevent the self-locking effect of throats by the fact that the branch pipe as an edge pipe along a portion of the elliptical boundary is arranged between the screen surface and the housing wall. A similar construction is also shown in DE-AS 26 12 917, with the difference that the cleaning bodies are drawn off in the middle of the housing. In both cases, the arrangement of the pipes, which are slotted and in which eddy formation occurs due to the flow of exchanger liquid, largely prevents cleaning bodies from being deposited. A disadvantage here is that the construction is again relatively complicated, in particular extensive and difficult welding work is necessary so as not to create areas with dead flow due to inaccurate work in the pipe branch, where in turn cleaning bodies can be deposited, which in turn can change the Flow conditions and thus could lead to further deposits of cleaning bodies until finally the entire suction device for the cleaning bodies is clogged. A construction similar to DE-PS 12 27 040 is also shown in DE-PS 13 03 750, and reference should also be made to the two German patents 862 456 and 894 699, which were the first to deal with this process for self-cleaning heat exchangers.

The object of the invention is to simplify the device for branching off cleaning bodies of the type mentioned both with regard to manufacture and with regard to maintenance, without the backwash cleaning possibilities being impaired and without the risk that cleaning bodies can become self-locking in throats.

According to the invention the object is achieved in that the at least one screen surface ends in the vicinity of the branch housing wall (which makes it easier to remove the cleaning bodies without increasing the overall length), and in that there is a transition surface between the upstream screen surface and the housing wall, where Radius of curvature or angle at the transition between screen surface and transition surface on the one hand and the angle between the transition surface and housing wall on the other are chosen so that self-locking of the cleaning body does not occur. For this purpose, the radius of curvature should be larger than the diameter of the cleaning body. If the transition surface and sieve surface or housing wall form an angular corner, the angle should be at least 90 ⁰ (although slightly more acute angles, e.g. 85 °, may be sufficient). This will surely prevent the accumulation of cleaning bodies due to jamming effects. The transition surface can be formed by an edge plate, but also by a kink or curvature or fillet on the screen surface.

In order to reduce the overall length, it can be advantageous to provide two branch connections, in which case, according to a favorable further development of the invention, two sieve surfaces are provided, which are formed by sieves which are roof-like to one another and with the ridge in the counterflow direction.

For the purpose of countercurrent flushing, the one sieve surface or both sieve surfaces, if two sieve surfaces are provided, can each be rotated about an axis. With this construction, therefore, only two axes are necessary, which would have to be stored in the housing of the device, whereas in the prior art considerably more axes are necessary. Advantageously, the present construction can be modified such that the two roof-shaped screens are rigidly connected to one another and can be rotated together about an axis, which then lies essentially on the bisector of the angle formed by the two screen surfaces. This would only require a single actuation axis for backwashing, which reduces the number of required axis seals to two or, if only one of the axes is passed through the pipe wall, one.

Screen surface, edge plate and housing wall expediently form a kind of funnel, which ends at its narrower end in the discharge nozzle, which in turn through the housing wall to the outside is led. According to a further embodiment of the invention, a second (lower) sieve can be arranged between this end of the funnel and the discharge nozzle, which can be essentially funnel-shaped and is arranged such that it forms a funnel continuation.

It may be expedient to also pivotally arrange this lower sieve (in the case of two or more discharge ports there may also be more sieves) so that these sieves can also be cleaned by backwashing. In order not to have to pass a second actuation axis through the housing wall, a drive lever is articulated at one end at the narrow end of the lower sieve, the other end of which is connected to an inwardly directed extension of the free end of the upper sieve, according to yet another embodiment, such that when the upper sieve is pivoted from the working position into the cleaning position, the lower sieve is also pivoted from the working position into the cleaning position. Alternatively, the lower sieve could also be rigidly connected to an associated upper sieve and thus pivotable with it.

This would ensure that all screens of the arrangement, be it an upper and a lower screen or also several upper screens and one or more lower screens, each with only a single actuation axis for cleaning purposes, so that u. U. only a breakthrough in the housing wall would have to be arranged.

The already mentioned arrangement of four discharge ports, two at the downstream end of each of the screen surfaces forming a roof, enables a further reduction in the overall length, in particular if lower screens are present. In addition, a pipe partition can be provided with four discharge pipes, which divides the upper roof-shaped sieve into two halves, which increases the stability of the arrangement and also enables the actuating shaft to be additionally supported in this pipe partition. Means this additional storage, it is even possible to also divide the actuating shaft and divide the entire arrangement into two branch halves which can be backwashed independently of one another.

Four, two "roofs" forming upper sieves can also be individually pivoted next to one another, the inner upper sieves opening in a lower, funnel-shaped sieve and this opening into one (or more) discharge pipe. The lower sieve could be rigidly connected to the adjacent sieve surface and pivotable with it, or it could consist of several, e.g. B. consist of two parts, one part can be connected to an adjacent upper sieve, the other part to the other upper sieve or also to the exhaust pipe or the housing wall.

The invention is explained in more detail below on the basis of exemplary embodiments which are illustrated in the drawings.

• Fig. 1 einen schematischen Längsschnitt durch eine Vorrichtung zum Abzweigen von Reinigungskörpern mit dem erfindungsgemäßen Randblech, wobei diese Ausführungsform ein verschwenkbares Einzelsieb besitzt;
• Fig. 2 eine Detailansicht des erfindungsgemäßen Randbleches;
• Fig. 3 eine ähnliche Konstruktion wie Fig. 1, jedoch mit zwei Abzweigstutzen und zwei zueinander dachförmig angeordneten Trennsieben;
• Fig. 4 eine ähnliche Konstruktion wie Fig. 3, jedoch mit einstückig angeordneten Sieben zwecks gemeinsamer Verschwenkung um nur eine Achse;
• Fig. 5 eine Anordnung ähnlich der Fig. 4, jedoch mit zusätzlich angeordneten und zusammen mit den oberen Sieben verschwenkbaren unteren Sieben;
• Fig. 6 eine schematische Draufsicht auf die Anordnung der Fig. 5;
• Fig. 7 eine Anordnung der Fig. 5 in einer Stellung, in der die Siebe zur Rückspülung verschwenkt sind;
• Fig. 8 eine schematische Draufsicht auf eine Anordnung ähnlich der der Fig. 5, jedoch mit jeweils zwei trichterförmigen unteren Sieben auf jeder Seite zum Zwecke der Baulängenverkürzung;
• Fig. 9 eine Darstellung ähnlich der Fig. 8, jedoch mit zusätzlicher Rohrtrennwand;
• Fig. 10 eine Darstellung ähnlich der Fig. 6, jedoch mit verringerter Firstbreite des dachförmigen Siebes zur Vergrößerung des erreichbaren Schwenkwinkels;
• Fig. 11 eine Darstellung ähnlich der Fig. 3, jedoch mit vier oberen Trennsieben und mittig angeordnetem unteren Sieb; und
• Fig. 12 eine Darstellung ähnlich der Fig. 3, jedoch mit zusätzlich angeordneten und mit den oberen Sieben starr verbundenen unteren Sieben.

It shows

• 1 shows a schematic longitudinal section through a device for branching off cleaning bodies with the edge plate according to the invention, this embodiment having a pivotable individual sieve;
• 2 shows a detailed view of the edge plate according to the invention;
• FIG. 3 shows a construction similar to that of FIG. 1, but with two branch connections and two separating screens arranged in a roof-like manner with respect to one another;
• FIG. 4 shows a construction similar to FIG. 3, but with sieves arranged in one piece for the purpose of joint pivoting about only one axis;
• 5 shows an arrangement similar to FIG. 4, but with additionally arranged lower sieves which can be pivoted together with the upper sieves;
• Fig. 6 is a schematic plan view of the arrangement of Fig. 5;
• 7 shows an arrangement of FIG. 5 in a position in which the screens are pivoted for backwashing;
• 8 shows a schematic plan view of an arrangement similar to that of FIG. 5, but with two funnel-shaped lower sieves on each side for the purpose of shortening the overall length;
• Fig. 9 is a representation similar to Figure 8, but with an additional pipe partition.
• FIG. 10 shows a representation similar to FIG. 6, but with a reduced ridge width of the roof-shaped sieve in order to enlarge the achievable swivel angle;
• FIG. 11 shows a representation similar to FIG. 3, but with four upper separating sieves and a centrally arranged lower sieve; and
• Fig. 12 is a representation similar to Fig. 3, but with additionally arranged and rigidly connected to the upper sieves lower sieves.

1 shows a particularly simple form of the device 10 according to the invention for branching off discrete cleaning bodies 1 from the main stream of a medium flowing through a heat exchanger, the flow of this main stream being indicated by the arrows 12. As already stated at the beginning, the cleaning bodies 1 serve to remove deposits from the tubes of the heat exchanger (not shown), or to prevent their formation at all, so that the medium containing the cleaning elements causes the system to self-clean. The cleaning bodies usually consist of sponge rubber balls with a diameter that is slightly larger than the diameter of the heat exchanger tubes to be cleaned. Of course, other materials can also be used for the cleaning bodies, for example plastic foam material. It is only important that the cleaning bodies have approximately the same specific weight during operation as the heat exchange medium, so that undesired segregation processes do not occur. The feeder device 10 according to the invention according to the embodiment shown in Fig. 1 comprises a cylindrically constructed branch housing 2 which expediently the same diameter as the light coming from the heat exchanger conduit (not shown) to which the upper end (inlet end) of the branch ^g ehäuses 2 can be applied pressure-tight by means of a flange connection 14. The lower end (outlet end) of the housing 2 is also connected in a pressure-tight manner via a flange connection 16 to a line of the same diameter, which represents a continuation of the heat exchanger circuit.

To branch off the cleaning elements 1 carried in the heat exchanger medium, a separating screen 3 is used, which is arranged in the axial housing obliquely to the flow 12 in such a way that the cleaning bodies 1 are guided in the direction of a branch pipe 4, from which they are withdrawn by means of arrangements, not shown can. The shape of the separating sieve 3 is elliptical in order to obtain an exact adaptation to the cylindrical housing wall of the branch housing 2. The separating sieve 3 has openings which are so small that the cleaning elements 1 cannot pass through the openings, even taking into account their flexibility. On the other hand, the permeability of the sieve should be so large that there is no significant impediment to the axial flow 12 through the sieve 3.

During the course of operation, foreign bodies can get caught on the sieve surface, which leads to an increase in flow resistance, which impair operation. In order to be able to remove these foreign bodies, the separating sieve 3 can be pivoted about an actuating shaft 5 into a backwashing position (not shown), in which the sieve surface 18 pointing in the upstream direction during normal operation comes into an outflow position, while at the same time the sieve surface 20 previously located in the downstream direction comes into the upstream position is coming. The flow directed through the sieve reverses its direction and flushes away the foreign bodies deposited on the surface 18. The screen 3 is then brought back into the normal position, which is shown in FIG. 1.

So that the fillet angle between the screen surface 18 and the inner wall surface of the branch housing 2 does not lead to jamming and deposition of cleaning bodies 1, a transition surface in the form of an edge plate 6 is now provided according to the invention between the screen surface 18 and the inner housing wall 22 such that between the upstream sieve surface 18 and upstream edge sheet metal surface 24, on the one hand, and between this edge sheet surface 24 and housing wall surface 22, on the other hand, a too acute fillet angle is prevented. A fillet angle of at least 90 ° is preferably selected. Such a fillet angle prevents with certainty that cleaning bodies 1 get stuck in the withdrawal area of the screen surface 18, see also FIG. 2, which shows this area in greater detail. The edge plate can be flat or curved, although the radius of curvature should be larger than the radius of the largest cleaning body to be branched off. The flat or curved transition surface in the manner specified can also be formed instead of an edge plate by kinking the sieve surface or by a curvature or fillet on the edge of the sieve surface (not shown).

The construction shown in Fig. 1 has the disadvantage that it has a relatively large length. 3 shows an improved construction in this respect, which instead of only one separating screen 3 now has two separating screens with corresponding branch branches 4 and edge plates 6. The two separating screens 3 can be pivoted independently of one another about axes 5 and, in normal operation, are arranged in such a way that they form a roof with a roof ridge 24 pointing in the countercurrent direction. Otherwise, the method of operation is quite analogous to that which was described with reference to FIG. 1.

The arrangement of the axis 5 is expediently carried out so that the pressure created by the flow 12 and the flow resistance of the sieve 3 is divided equally between both lever arms of the sieve 3, so that essentially no flow about the axis 12 from the flow 3 onto the sieve 3 5 torque is created. The arrangement could also be chosen so that a low torque occurs in the direction in which the screen 3 is rotated into its working position, so that a kind of self-locking of the lever 3 is achieved in Arbeitsstelluhg. Because of the high flow velocities common today, a slight displacement of the axis 5 from the neutral position is sufficient to achieve the desired self-blocking effect, but on the other hand also a change of the sieve 3 in the countercurrent flushing direction without applying large torques to the axis 5 while the medium is flowing through to enable.

As a comparison between FIGS. 1 and 3 shows, the arrangement of two screens allows a considerable shortening of the branch housing 2 with the same housing diameter. The disadvantage that is accepted is that two actuation axes 5 must be provided, which complicates the drive arrangement and also requires the arrangement of at least two breakthrough seals, which increases the susceptibility to maintenance. Fig. 4 shows another embodiment in which this Pro bleme are not present. For this purpose, the two individual sieves 3, which can still be seen in FIG. 3, are combined to form a roof-shaped sieve 30, in that the upper ends of the individual sieves 3 are firmly united and the lower ends are held apart by means of a strut 26. Due to the rigid connection of the two sieve parts 3 to a one-piece sieve 30, only a single axis 5 is required, around which the sieve construction 30 can be rotated for the purpose of backwashing. If the screen surface 18a is to be rinsed, the screen 30 is pivoted counterclockwise about the axis 5, to the extent that the surface of the screen 18a comes to lie in the downstream direction. Conversely, the screen 30 must be rotated clockwise if the screen surface 18b is to be cleaned by backwashing. The arrangement of the edge plates 6 is to be carried out in this construction in such a way that the screen 30 can pivot past the edge plates 6. In addition, the fulcrum 5 must be placed so that the lower end 32 of the two partial screens 3 does not, or at least not yet, touch the inner wall of the housing 2 when the opposite partial screen 3 has just reached the rinsing position. The axis of rotation 5, which is expediently on the bisector of the two surfaces 18a, 18b, must not be too far from the imaginary line connecting the two surfaces 31, on the other hand, in order to avoid a lever arm that is too large, the pivot point must not be too close to this Line.

The construction shown in Fig. 4 also allows the attachment of so-called lower screens, which are advantageous in certain applications and are also already used in the prior art. 5 so that additional pivot axis bushings are not necessary due to the attachment of lower sieves, which should also be backwashable, a lever construction is provided according to FIG. 5, which also pivots when the upper sieve 30 is pivoted for the purpose of backwashing to pivot the lower sieves 32 accordingly leads to the backwash position.

Such lower sieves can also be provided in the construction according to FIG. 3, see FIG. 12, the lower sieves 32 being rigidly connected to the associated upper sieve 3 and being pivotable therewith for the purpose of backwashing. However, the backwash position for the lower sieves is somewhat less favorable here than in the construction shown in FIG. 5, but the arrangement is simpler for this.

In the embodiment shown in FIG. 5 (see also the illustration in FIG. 6) and also in the arrangement shown in FIG. 12, the screen surface 18a or 3 forms together with the inner wall 22 of the housing 2 and the surfaces 24 of the two Share existing edge plate 6 a kind of funnel, which merges at its lower end into a second funnel, which is formed by the sieve surfaces 34 of the lower sieve 32 and by the inner wall 22 of the housing 2 and a further surface 36, which the two sieve surfaces 34 of lower sieve 32 supports. This surface 36 can be a closed plate or in turn a sieve surface. The outlet opening of the funnel formed by the lower sieve 32 opens into the discharge nozzle 4.

In the embodiment shown in FIGS. 5 and 6, the surface 36 which supports the sieve surface 34 is pivotably supported at its one (upper) end via an axis 38 suitably fastened to the inner housing wall, while at the other end of the surface 36 a lever 6 is articulated, the other end of which is articulated on a projection 40 of the screen 30. This link connection is made in such a way that when the screen 30 is pivoted by rinsing, for example, the screen surface 18a (see FIG. 7), at least one of the two lower screens (in FIG. 7 it is the lower screen 32b) may reach the backwash position. The other lower sieve (32a) reaches its backwashing position when the upper sieve 30 is pivoted into the washing position in which the sieve surface 18b is cleaned (not shown in FIG. 7).

The construction shown in Fig. 7, which consists of a roof-shaped upper sieve 30 and two funnel-shaped lower sieves 32, can thus be brought into the backwash position by a single pivot axis 5, with either a hand crank 42 being actuated for this purpose, or a corresponding mechanical drive, not shown, could take place.

It is important that only a single passage in the housing wall of the housing 2 is required to make this drive, while all other bearings can be realized by devices attached to the inner wall of the housing, which do not require a bushing and therefore do not result in any sealing problems.

It should also be pointed out that the surface 36 can have a projection 7 in order to form a rear partition for the discharge pipe 4 when the lower screen 32 is in the working position.

As can be seen in FIG. 6, the sieve surfaces 18a, 18b are not curved at their upper regions lying near the housing wall, but are made in a straight line and a further edge plate is used to close the opening between the edge of the sieve surface 18b and the housing wall 42 is provided so as to enable pivoting in both directions. The pivoting angle can be increased further if, according to FIG. 10, the width of the ridge 24 is reduced and the further edge plates 42 are correspondingly widened, which could be necessary in particular in the case of a steeper screen inclination to allow the screen to be swiveled into the backwash position.

As can still be seen from FIG. 7, the lower end of the screen surface 18a (FIG. 4 labeled 32) must be able to pivot freely downwards, which must be taken into account in the construction of the linkage, in particular the connecting lever 9.

The connecting lever 9 may have to have a corresponding curvature in order to allow the screen surface 18a to pivot downward.

A further shortening of the overall length, in particular when using funnel-shaped lower sieves, can be achieved if, according to FIG. 8, two discharge ports 4 are arranged on each side, each of which has its own funnel-shaped lower sieve 32, so that a total of four lower sieves 32 are present are.

This arrangement shown in FIG. 8 can still be designed according to FIG. 9 in that a partition 44 is provided perpendicular to the pivot axis 5 in such a way that it separates the two lower sieves 32 on each side and also the upper sieve 30 in two partial sieves 30a, 30b. This construction is particularly advantageous for larger pipe diameters. The illustration in FIG. 9 shows an embodiment with an additional bearing 46 for the shaft 5 in the partition wall 44, as a result of which the shaft 5 in the region of this bearing 46 could be divided into two shafts 5a and 5b which can be actuated independently of one another. Of course, a continuous shaft 5 with only one drive is also possible.

The construction according to FIG. 11 also shortens the overall length, in which four upper sieves 3 are arranged next to one another and in this way form two “roofs”. The two inner upper sieves 3i open into a lower, at least in the direction of the pivot axes in cross section funnel-shaped downward sieve 32i, the z. B. is rigidly connected to one side wall 50 with an inner upper sieve 3i and can be pivoted therewith, while the side wall 50 either with the other inner upper sieve 3i or, more simply, with the housing wall or with the exhaust pipe 4i for which can collect in the iter sieve 32i collecting cleaning bodies.

Instead of edge plates 6, other arrangements can also form a transition surface between sieve 3 and housing wall 22, which prevent jamming of cleaning bodies, such as bulging of the inner tube wall, kinking of the sieve edge and the like. the like

Claims (20)

1.Device for branching in a discrete cleaning bodies carried in a fluid flowing through a tubular heat exchanger from the main flow of the fluid, consisting of a branch housing through which axial flow flows and a separating sieve device arranged therein with at least one sieve surface arranged obliquely to the flow, which ends at the outflow end in a branch nozzle , wherein the screen surface can be pivoted for cleaning purposes to such an extent that the screen surface side previously located in the upstream direction comes to lie in the downstream direction, characterized in that the at least one screen surface (18) ends in the vicinity of the branch housing wall (22), and that there is a transition surface (6) is arranged between the upstream sieve surface (18) and the housing wall (22), the radius of curvature or angle at the transition between the sieve surface (18) and the transition surface (24) on the one hand and the radius of curvature or angle between the transition surface (24) and the housing wall ( 22) other its are chosen so that self-locking of the cleaning body does not occur. 2. Device according to claim 1, characterized in that the radius of curvature is greater than half the diameter of the cleaning body or the angle is at least 90 °. 3. Apparatus according to claim 1 or 2, characterized in that the transition surface is formed by an edge plate (6) or by a kink or curvature or fillet on the screen surface (18). 4. Device according to one of claims 1 to 3, characterized in that two sieve surfaces (18a, 18b) are provided, which are formed by roof-like to each other and with the ridge (24) in the countercurrent direction sieves (3). 5. The device according to claim 4, characterized in that the two screens (3) rigidly connected to one another and rotatable about an axis (5) which lies essentially on the bisector of the angle formed by the two screen surfaces (18a, 18b). 6. The device according to claim 5, characterized in that the free ends (32) of the angularly arranged screens (3) are connected to each other by struts (26) and these carry the axis (5). 7. Device according to one of claims 1 to 6, characterized in that the screen surface (18), edge plate (24) and housing wall (22) form a funnel, which opens at its narrower end into a discharge nozzle (4) through the housing wall is led to the outside. 8. The device according to claim 7, characterized in that a second (lower) substantially funnel-shaped sieve (32) is arranged between the funnel end and discharge port (4), which forms a funnel continuation and whose outlet end opens into the discharge port. 9. The device according to claim 8, characterized in that the lower sieve (32) at its wider end about an attached to the housing wall and parallel to the pivot axis (5) of the first (upper) sieve (3; 30) lying axis (38) is pivotally mounted. 10. The device according to claim 9, characterized in that a drive lever at the narrower end of the lower sieve. (9) is articulated with one end, the other end of which is connected to an inward projection (40) of the free end (32) of the upper sieve (3), such that when the upper sieve (3; 30) is pivoted from Working position in the cleaning position, the lower sieve (32) is also pivoted from the working position to the cleaning position. 11. The device according to claim 8, characterized in that the second funnel-shaped sieve (32) with the first sieve (3) forms a rigid unit and is pivotable with this (z. B. Fig. 12). 12. Device according to one of claims 4 to 11, characterized in that at the outflow end of each of the roof surfaces forming sieve surfaces (18a, 18b) two discharge ports (4) are provided. 13. The apparatus according to claim 12, characterized in that a funnel-shaped lower sieve (32) is provided for each discharge nozzle (4). 14. The apparatus according to claim 12 or 13, characterized in that a pipe partition (44) divides the upper roof-shaped screen into two screen halves (30 30b). 15. The apparatus according to claim 14, dadur gel indicates that the Rohrtrenm and (44) ei e storage ('6) for the actuating shaft (5). 16. The apparatus according to claim 15, characterized in that the actuating shaft (5) is divided in the region of the bearing (46) and thereby two mutually independently rotatable actuating shafts (5a, 5b) for independent backwashing of the upper screen halves (30a, 30b) and, if necessary lower sieves (32) are present. 17. Device according to one of claims 1 to 3, 7 to 8, 11 to 12, 14 to 16, characterized in that a total of four individually pivotable screen surfaces (18) are provided and are roof-like during separation operation, the two inner screen surfaces in one open second sieve (32i), which has a funnel-like profile in the swivel axis direction and a funnel-like or rectangular profile perpendicular thereto, the funnel end opening into a discharge pipe (4i) for cleaning bodies. 18. The apparatus according to claim 17, characterized in that the second screen (32i) is rigidly connected to one of the screen surfaces (18). 19. The apparatus according to claim 18, characterized in that the second screen (32i) is rigidly connected to one of the screen surfaces (18c). 20. The apparatus according to claim 19, characterized in that the second sieve (32i) is in several parts and a part with an inner sieve surface (18c) and other parts (z. B. 50) with the other inner sieve surface (18d), the Discharge tube (4i) or the housing wall (22) is connected.

Images