Press screw separator

Abstract

The invention relates to a press screw separator (1) for separating solid constituents out of a pulp containing solid and liquid constituents, comprising: a housing (2), a cylindrical strainer (4) which is arranged in the housing (2), and a clearing element (3) which is arranged inside the strainer (4) and is mounted rotatably about a longitudinal axis (6) of the strainer (4) for squeezing-out the pulp, wherein the housing (2) comprises a first housing part (20) and a second housing part (21), wherein the second housing part (21) adjoins the first housing part (20) in the direction of the longitudinal axis (6), wherein a first strainer region (41) of the strainer (4) is mounted non-rotatably in the first housing part (20), and wherein a second strainer region (42) of the strainer (4) is mounted without play in the second housing part (21) in the radial direction of the strainer and directly contacts the second housing part (21).

Description

[0001] Press screw separator

[0002] The present invention relates to a press screw separator for separating solid components from a slurry containing solid and liquid components.

[0003] Press screw separators are used to press out slurry. The slurry can be, in particular, manure or wastewater. The wastewater can originate from agricultural, municipal, and industrial plants, although it should always be separated into solid and liquid components. In some cases, it is advantageous to add precipitants or flocculants to the slurry before pressing. The housing of the press screw separator usually contains a cylindrical screen, within which a rotating scraper element. The scraper element conveys the slurry through the press screw separator and presses it. The liquid components of the slurry pass through the screen, while a plug of solids forms within the screen. The rotating scraper element conveys the plug of solids to one end of the press screw separator, where it is ejected.The torque is transferred from the clearing element to the screen via the solid plug. Therefore, the screen must be mounted in the housing in a rotationally fixed manner.

[0004] In practice, it has been shown that when solids are pressed to a high dry content, a high bursting pressure acts on the screen. EP 2 938 418 B1 describes a press-screw separator with a frame mounted in the housing of the press-screw separator, in which part of the screen area is mounted. This frame supports the screen and thus prevents screen failure. The disadvantage of this solution in terms of manufacturing costs and maintenance is that the frame requires an additional component in the housing.

[0005] DE 202011105765 U1 shows a screen assembly for a screw press separator, comprising a rigid, hollow-cylindrical shell and a hollow-cylindrical screen resting against the inner surface of the shell. Supporting rods are attached to the outside of the shell. These support rods mount and secure the screen assembly in the screw press separator. Further relevant prior art is shown in DE 102011080865 U1.

[0006] Therefore, based on the prior art described above, the object of the present invention is to create a technically simple press screw separator of the type mentioned at the outset, which enables safe, reliable and low-maintenance operation with simple and cost-effective production.

[0007] The object is achieved by a press screw separator for separating solid components from a slurry containing solid and liquid components, comprising a housing, a cylindrical sieve which is arranged in the housing, and a clearing element arranged within the sieve and mounted so as to be rotatable about a longitudinal axis of the sieve for pressing out the slurry, wherein the housing comprises a first housing part and a second housing part, wherein a first sieve region of the sieve is mounted in a rotationally fixed manner in the first housing part, and wherein a second sieve region of the sieve is mounted in the second housing part without play and directly contacts the second housing part.

[0008] According to the invention, this object is achieved by a press screw separator comprising a housing in which a sieve is mounted. As is usual with other press screw separators, this housing absorbs all radial and axial forces acting during operation. The press screw separator according to the invention usually comprises a cover surrounding the housing in order to bundle and drain off the liquid phase after separation. This cover can be removed quickly and easily for maintenance work. Furthermore, the press screw separator according to the invention comprises a clearing element arranged within the sieve and mounted for rotation about a longitudinal axis of the sieve for pressing out the slurry. The sieve is therefore usually cylindrical, with the housing also preferably being cylindrical. As a load-bearing component, this housing absorbs all radial and axial forces occurring during operation.Part of the screen is accommodated in this housing without any play. Therefore, in addition to absorbing all other radial and axial forces, the housing according to the invention also provides a supporting function for a screen area against the bursting pressure prevailing in this area, so that the screen can absorb significantly higher forces than would be the case without the supporting function of the housing.

[0009] According to the invention, a first sieve section of the sieve is mounted in the housing in a rotationally fixed manner, while a second sieve section of the sieve is mounted in the housing without any play. Thus, the arrangement according to the invention allows the reinforcing second section of the housing to be provided only at those points on the sieve where particularly high forces occur and which are therefore potential failure points. The first sieve section, which is not supported by the housing, can still be mounted in the housing in a rotationally fixed manner. This allows the housing to support the sieve in the second sieve section, so that no deformation and thus no failure of the sieve is possible here. The second sieve section is in particular the section of the sieve where the highest dry matter contents occur within the press screw separator. This means that in the second sieve section the slurry is largely separated into its solid and liquid components and the plug forms.In other words, the second screening area is located behind the first screening area in the conveying direction of the clearing element.

[0010] The solution according to the invention differs from EP 2 938 418 B1 in that a two-part housing is provided, so that no separate frame has to be inserted into the housing. In the solution according to the invention, the second sieve area is therefore not connected to a separate frame, but directly to the second housing part, thereby eliminating the need for a frame that would have to be inserted into the housing. This is made possible by the second housing part, which adjoins the first housing part in the longitudinal direction of the sieve. Compared to the devices of DE 202011105765 U1 and DE 102011080865 A1, the advantage is achieved that one part of the sieve can be mounted in a rotationally fixed manner and one part can be mounted without play.

[0011] The screen preferably comprises a plurality of bars oriented parallel to the longitudinal axis. Such bar screens exhibit advantageous properties for use in press screw separators, particularly since they lack circumferentially extending elements that could be damaged by the solid plug conveyed by the clearing element.

[0012] Furthermore, it is preferably provided that the supporting second region of the housing comprises support rings positioned perpendicular to the rotation axis. This has the advantage that only the supporting bars of the screen are covered by the supporting housing. The area between the supporting bars of the screen, which is important for separating the liquid components of the slurry, remains free. This enables high performance of the press screw separator. As an alternative to the support rings, a rolled-up slotted sheet or a rolled-up perforated sheet could also be used. The support rings are advantageous over such solutions because they do not cover any part of the open screen surface.

[0013] Furthermore, it is preferably provided that the supporting region of the housing has at least one reinforcing strip extending parallel to the longitudinal axis. In particular, it is provided that drill holes, threaded holes, and / or threaded rods are provided in the reinforcing strip, by means of which a retaining strip can be screwed to the housing. In particular, the reinforcing strip enables the frame to be made very rigid, which can prevent, in particular, deformation of the screen and the housing.

[0014] Advantageously, the second sieve region has a recess in the direction of the longitudinal axis. A lug of the housing can preferably engage in this recess in order to prevent rotation of the second sieve region about the longitudinal axis relative to the housing. Since, as described above, the rotation of the clearing element is transferred to the sieve, torsion within the sieve can be prevented in this way. It is thus possible to keep unnecessary stresses away from the sieve. Furthermore, the lug can be designed to mount the sieve within the housing. Alternatively or additionally, the lug can be designed to tension the sieve within the housing. This can be achieved in particular by the sieve having a cylindrical base body, wherein a slot parallel to the longitudinal axis is present over the entire outer surface.Therefore, a nose engaging in the slot with a larger dimension than the slot can increase the outer diameter of the screen in order to press the screen into the frame.

[0015] In a preferred embodiment, the housing has a retaining strip that can be connected to the rest of the housing. Particularly preferably, the retaining strip can be screwed to the housing. This preferably forms the nose of the housing. This has the advantage that the nose of the housing is removable, which, for example, facilitates the installation and / or removal of the screen.

[0016] Furthermore, it is preferably provided that the second screening area occupies a portion of up to 30%, in particular up to 50%, of the screen. As previously described, the highest forces within the press screw separator occur within the second screening area. Therefore, according to the invention, the second screening area is to be selected according to the stated values ​​to ensure that screen failure due to excessive forces is excluded.

[0017] Furthermore, it is preferred if the press screw separator comprises an inlet housing on which the housing is mounted on one side to absorb torques from the clearing element. The housing is thus mounted on only one side and protrudes freely on the side facing away from the inlet housing.

[0018] Particularly in the aforementioned embodiment, it may be preferred if the first housing part comprises at least two bars that support both the first screening area and the second housing part. The bars can thus preferably extend between the inlet housing and the second housing part, whereby the first screening area can be supported on these bars simultaneously. Particularly preferably, only two bars are used, and the first housing part has no further elements in the circumferential direction in the area of ​​the bars to enable deformation of the first screening area.

[0019] Furthermore, the press screw separator can preferably comprise a cover arranged around or beneath the housing to collect the slurry passing through the housing. Thus, the housing can be designed to absorb the torque without having to assume the function of collecting the separated liquid, which can be done by the cover, which in turn does not have to absorb any torque from the clearing element. A particular advantage here is that more space is available between the housing and the cover for additional components.

[0020] In particular, a washing device can be arranged in this space between the housing and the cover, which preferably comprises a washing ring driven by a linear drive and arranged around the housing. Using spray nozzles on the washing ring, a large portion of the screen can be washed without having to remove the screen from the press screw separator.

[0021] The invention will now be described in detail using an exemplary embodiment and taking into account the accompanying drawings. In the drawings:

[0022] Fig. 1 is a schematic representation of a press screw separator according to an embodiment of the invention, and

[0023] Fig. 2 is a schematic representation of the second screening area of ​​the screen together with the second housing area of ​​the press screw separator according to the preferred embodiment of the invention.

[0024] Figure 3 shows a sectional view of the second housing part and the second screening area. Figure 4 shows a schematic representation of the press screw separator according to the invention in a particularly preferred embodiment.

[0025] Fig. 1 shows a press screw separator 1 having a housing 2. Furthermore, the housing 2 is divided into a first housing section 20 and a second housing section 21. Both the first housing section 20 and the second housing section 21 are usually essentially cylindrical and can each have a longitudinal axis. To form the housing 2, the two housing sections 20, 21 are arranged next to one another along the longitudinal axes to form an essentially cylindrical housing 2. To connect the two housing parts 20, 21 to one another, a flange connection is preferably used, as shown in Figure 1, although another type of connection, such as a welded connection or a slip-on connection, can also be used.

[0026] In the following, only those components of the press screw separator 1 that are relevant to the present invention are described. All remaining components correspond to those used in known press screw separators.

[0027] Arranged within the housing 2 is a clearing element 3, which in particular comprises two circumferential spirals. The clearing element 3 can compress a slurry so that liquid components can be separated from solid components. The clearing element thus has a conveying direction towards which the slurry is conveyed in order to compress it. For this purpose, a sieve 4 is provided which extends cylindrically around the clearing element 3. The sieve 4 has a longitudinal axis 6, which is also the longitudinal axis of the clearing element 3. The longitudinal axis 6 of the sieve usually coincides with the longitudinal axis of the housing sections 20, 21. Furthermore, the sieve 4 is divided into a first sieve section 41 and a second sieve section 42. The first sieve section 41 can have a design that differs from the design of the second sieve section 42.Furthermore, it is preferably provided that the first screening area 41 and the second screening area 42 are installed separately from one another.

[0028] In the example shown in Fig. 1, the first sieve region 41 is connected to the first housing region 20 via holding brackets not visible in Fig. 1 in such a way that only tangential forces are transmitted, thus preventing the sieve 4 from rotating with the clearing element 3. However, it can be provided in particular that the first sieve region 41 is only mounted in a rotationally fixed manner and not without play in the radial direction of the sieve 4, i.e. in particular an elliptical deformation of the first sieve region 41 is made possible. In other words, the first sieve region 41 can be mounted with one degree of freedom in the radial direction. In the present invention, the first housing region 20 can be formed, for example, by two or more rods that extend in the axial direction.The rods can, on the one hand, each support the first screen area 41 linearly (so that the first screen area 41 can deform elliptically, for example, between the rods) and, on the other hand, support the second housing area 21. The first housing area 20 could, for example, comprise a flange ring at the end of the rods facing the second housing area 21 to facilitate the connection of the second housing area 21.

[0029] The second screening area 42 is mounted directly in the second housing area 21 in the radial direction of the screen 4 without play. As a result, the second housing area 21 largely prevents deformation of the second screening area 42. The second screening area 42 and the second housing area 21 are arranged directly in front of an outlet 22 of the housing 2, since this is where the highest forces act on the screen 4. This results from the fact that the slurry is compressed across the longitudinal axis 6, i.e. in the conveying direction of the clearing element 3, whereby liquid components constantly pass through the screen 4 and the solid components of the slurry remain within the screen 4. Thus, the dry matter content of the solids within the screen 4 increases continuously as the solids approach the outlet

[0030] 22. The second housing section 21 prevents the second screen section 42 from being destroyed due to excessive forces. The second screen section 42 accounts for approximately 30-50% of the total length of the screen 4, which is sufficient for a supporting function with the second housing section. Overall, this enables safe and reliable operation because the screen 4 is protected from failure.

[0031] Fig. 2 shows an exploded view showing the second sieve region 42, the second housing region 21, and a retaining strip 7, which forms a nose of the second housing region, in a preferred embodiment. It can be seen that the second sieve region 42 has a recess 43 which extends over the entire outer surface of the second sieve region 42 parallel to the longitudinal axis 6 and is preferably reinforced by end strips. The retaining strip 7 can engage in this recess 43 and can in particular be screwed to the second housing region 21. For this purpose, the second housing region 21 has a reinforcing strip 24, in which bores are provided so that the retaining strip 7 can be screwed within the reinforcing strip 24. It is also possible for the retaining strip to be connected to the reinforcing strip 24 via other fastening means.This can be, in particular, a riveted connection or an adhesive connection. The second housing region 21 can have additional reinforcement strips 24, although not every reinforcement strip 24 needs to be provided with a retaining strip 7. In particular, it is provided that only one retaining strip 7 is arranged on the second housing region 21.

[0032] The screen 4 is designed, in particular, as a bar screen. Therefore, the screen 4 has a plurality of bars 44 oriented along the longitudinal axis 6. The spacing of the bars 44 defines the gap width of the screen, allowing the quality of the solid to be pressed out to be determined. The longitudinal bars 44 are connected via several annular support bars 45 extending around the longitudinal axis 6.

[0033] Finally, it can be seen from Fig. 2 that the second housing section 21 is constructed, among other things, from rings 23. These rings 23 form the contact surface to the second sieve section 42, which is thus mounted in the second housing section 21 without any play in the radial direction of the sieve 4. The support rods 45 of the second sieve section 42 rest against the rings 23 of the second sieve section 42 without any play. The second housing section 21 thus absorbs the bursting pressure prevailing in the second sieve section 42. Therefore, failure of the second sieve section 42 and thus of the sieve 4 is virtually impossible. Furthermore, the area between the individual support rods 45 remains free and allows the separated liquid part of the slurry to drain freely.

[0034] Figure 3 shows a sectional view of the second housing part 21 and the second sieve region 42, which in the illustrated embodiment is formed with support rods 45. It can be seen at the first point S1 that the support rods 45 bear directly against the respective retaining ring 23, so that the second sieve region 42 is mounted in the second housing part 21 without play in the radial direction of the sieve 4. In principle, it would also be possible to mount the second sieve region 42 in the second housing part 21 in a different way without play in the radial direction of the sieve 4, e.g. if the second housing part 21 comprises a rolled-up elongated hole sheet or a rolled-up perforated sheet in which the sieve rests. Typically, the second sieve region 42 is also mounted in a rotationally fixed manner in the second housing part 21, since the retaining strip 7 engages in a recess in the second sieve region 42.However, a small gap may also occur at the second location S2 between the retaining strip 7 and the second sieve area 42 due to the torque during operation, since the second sieve area 42 is usually not mounted in a completely rotationally fixed manner.

[0035] Figure 4 shows a particularly preferred embodiment of the press screw separator 1 according to the invention with a drive 81 of the clearing element 3 and an inlet housing 82 for feeding the slurry to the clearing element. What is special about this embodiment is that, in contrast to other separators, no closed housing is provided which both absorbs the entire torque and drains off the separated liquid. Instead, the two-part housing 2 is provided, which absorbs the torque and allows the liquid to pass freely. In addition, there is a cover 83 which catches the liquid that has passed through the housing 2. The two-part housing 2, or more precisely the first housing part 20, is mounted on one side on the inlet housing 82. The other end of the housing, i.e. the second housing part 21, usually projects freely and is not mounted separately. The cover 83 is arranged loosely around the housing 2 and does not absorb any torque of the clearing element 3 orthe cloudiness.

[0036] Such a design with housing 2 and cover 83 allows, for example, a washing device to be provided between housing 2 and cover 83, which can clean a large part of the sieve. The washing device can, for example, comprise a washing ring 84, which is arranged between cover 83 and housing 2 and is movable in the axial direction by means of a linear drive 85. The sieve 4 can be cleaned by spray nozzles, which are provided around the circumference of the washing ring and are directed towards housing 2.

[0037] List of reference symbols:

[0038] 1 press screw separator

[0039] 2 housings

[0040] 20 First housing part

[0041] 21 Second housing part

[0042] 22 Outlet of the housing

[0043] 23 Retaining ring

[0044] 24 reinforcement strip

[0045] 3 clearing element

[0046] 4 sieve

[0047] 41 First screening area

[0048] 42 Second screening area

[0049] 43 Recess

[0050] 44 Longitudinal bar

[0051] 45 supporting rod

[0052] 6 Longitudinal axis

[0053] 7 Retaining bar

[0054] 81 Drive

[0055] 82 Inlet housing

[0056] 83 Cover

[0057] 84 washing ring

[0058] 85 Linear actuator

Claims

Patent claims:

1. Press screw separator (1) for separating solid components from a slurry containing solid and liquid components, comprising: a housing (2), a cylindrical sieve (4) arranged in the housing (2), and a clearing element (3) arranged within the sieve (4) and mounted rotatably about a longitudinal axis (6) of the sieve (4) for pressing out the slurry, characterized in that the housing (2) comprises a first housing part (20) and a second housing part (21), wherein the second housing part (21) adjoins the first housing part (20) in the direction of the longitudinal axis (6), wherein a first sieve region (41) of the sieve (4) is mounted in the first housing part (20) in a rotationally fixed manner, and wherein a second sieve region (42) of the sieve (4) is mounted in the second housing part (21) without play in the radial direction of the sieve (4), and the second housing part (21) is directly contacted.

2. Press screw separator according to claim 1, characterized in that the second screening area comprises annular support bars (45), wherein the second housing area (21) is designed with retaining rings (23) in which the support bars (45) of the second screening area (42) are mounted.

3. Press screw separator according to claim 2, characterized in that each retaining ring (23) in the second housing area (21) is opposite a support rod (45) of the second sieve area (42).

4. Press screw separator according to claim 2, characterized in that only every second, every third or every fourth support bar (45) of the second sieve area (42) is opposite a retaining ring (23) in the second housing area (21).

5. Press screw separator according to one of the preceding claims, characterized in that the second housing part (21) has at least one reinforcing strip (24) which extends parallel to the longitudinal axis (6).

6. Press screw separator according to one of the preceding claims, characterized in that the first sieve area (41) is elastically deformable.

7. Press screw separator according to one of the preceding claims, characterized in that the second sieve area (42) has a recess (43) in the direction of the longitudinal axis (6), into which a nose of the second housing part (21) engages in order to prevent rotation of the second sieve area (42) about the longitudinal axis (6).

8. Press screw separator according to claim 7, characterized in that the second housing part (21) comprises a holding strip (7) which can be connected, in particular screwed, to the second housing part (21) in order to form the nose of the second housing part (21).

9. Press screw separator according to one of the preceding claims, characterized in that the second sieve area (42) occupies a proportion of up to 30%, in particular up to 50%, of the sieve (4).

10. Press screw separator according to one of the preceding claims, characterized in that the second housing part (21) is connected to the first housing part (20) by means of a flange connection.

11. Press screw separator according to one of the preceding claims, characterized in that the press screw separator (1) further comprises an inlet housing (82) on which the housing (2) is mounted on one side to absorb torques of the clearing element (3).

12. Press screw separator according to one of the preceding claims, characterized in that the first housing part (20) comprises at least two bars which both support the first sieve area (41) and the second housing part (21).

13. Press screw separator according to one of the preceding claims, characterized in that the press screw separator (1) further comprises a cover (83) which is arranged around the housing (2) or under the housing (2) in order to collect the slurry which has passed through the housing (2).

14. Press screw separator according to claim 13, characterized in that the press screw separator (1) further comprises a washing device arranged between the housing (2) and the cover (83), which preferably has a Linear drive (85) driven washing ring (84) which is arranged around the housing (2).

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