Device and method for separating a liquid from a feedstock

Abstract

The invention relates to a device for separating a liquid from a feedstock, in particular material to be ground or granulate of plastic, having a screen drum (1) comprising a screen drum base (2), a screen drum wall (3) and an outlet side (4) opposite the screen drum base (2), having a feed device (15) for feeding the feedstock into the screen drum (1) and having a discharge device (9) arranged on the outlet side (4) of the screen drum (1) for discharging the feedstock separated from liquid, wherein the screen drum (1) rotates about its centre longitudinal axis (5) and guides off the liquid, characterised in that the feed device (15) has a feed opening arranged on the screen drum base (2) and that a conveying device with at least one conveying element (16) for conveying the feedstock to the outlet side is arranged in the screen drum (1). The method also relates to a method for separating a liquid from a feedstock.

Description

[0001] DEVICE AND METHOD FOR SEPARATED A LIQUID FROM A FEED MATERIAL

[0002] The invention relates to a device for separating a liquid from a feed material, in particular ground material or granulate made of plastic, comprising a screening drum comprising a screening drum base, a screening drum wall, and a discharge side opposite the screening drum base. The device comprises a feed device for feeding the feed material into the screening drum and a discharge device arranged on the discharge side of the screening drum for discharging the feed material separated from the liquid. The screening drum rotates about its central longitudinal axis, thereby discharging the liquid. Furthermore, the invention relates to a method for separating a liquid from the feed material using the device.

[0003] In addition to waste prevention, recycling or reusing the valuable materials contained in waste is an essential aspect of taking into account the limited amount of resources. Reusing these valuable materials makes an important contribution to environmental protection. Therefore, there is a great need to process valuable materials in such a way that they can be made available for further use.

[0004] When processing plastics, such as used PET bottles or related products, the recycled material is first shredded using shredders, cutting mills, or other suitable shredding technology. The resulting material is then washed to remove adhering residues such as contaminants. For the subsequent processing steps, it is necessary to separate the liquid from the cleaned material. Mechanical dryers are typically used for this purpose.

[0005] Mechanical dryers have been in use for years. According to the current state of the art, liquid separation is typically achieved using so-called billet dryers or press screws. The billet dryer, in which a high-speed rotor with impact elements drives the material through a screen basket, is characterized by high specific energy requirements and a high material loss rate due to fine abrasion. Press screws separate the liquid by forcing the material-liquid mixture through screen tubes with the aid of conveyor screws. A problem with this is that agglomerates often form. This can be problematic for subsequent process steps and therefore necessitates an additional step to separate the agglomerates. Furthermore, the operation of press screws is generally associated with high machine wear.

[0006] The present invention is therefore based on the object of designing and developing a device for separating a liquid from a feed material, in particular ground material or granulate made of plastic, in such a way that the liquid can be separated energy-efficiently, using simple means and with the least possible material abrasion loss and device wear. At the same time, a sufficiently good and homogeneous drying result should be achievable. Furthermore, the device according to the invention should be distinguished from competitive products. Furthermore, a method for separating a liquid from the feed material using the device should be specified. With the aid of the method, a drying process with continuous supply and removal of the feed material should be feasible.

[0007] According to the invention, the above object is achieved by the features of the independent claims 1 and 19.

[0008] The device mentioned at the outset is characterized in that the feed device has a feed opening arranged on the screen drum base and that a conveying device with at least one conveying element for conveying the feed material to the discharge side is arranged in the screen drum.

[0009] In accordance with the invention, it was first recognized that utilizing the centrifugal force generated by the rotation of the screening drum enables particularly simple and gentle drying of the feed material. The centrifugal forces press the wet feed material, which can be fed into the screening drum through the feed device at the bottom of the screening drum, against the screening drum wall. The screening drum wall is designed so that the liquid, but not the feed material, can be drained away. Therefore, no mechanical forces are applied to the feed material to separate the liquid. This results in extremely low fine abrasion and material loss, as well as low device wear. This also entails low energy input into the feed material, making the energy consumption of the device in question very low compared to previous mechanical dryers.

[0010] Furthermore, it has been recognized that a sufficiently long residence time of the feed material in the screening drum is necessary for a sufficiently good and homogeneous drying result. This is achieved by feeding the feed material to the screening drum through the feed device at the bottom of the screening drum. For this purpose, a feed opening is arranged at the bottom of the screening drum. The conveyor device arranged in the screening drum then continuously conveys the feed material from the bottom of the screening drum to the discharge side, where it is discharged in radial and tangential directions and can be removed by the discharge device. During conveyance to the discharge side, the feed material is also continuously circulated, which prevents the formation of agglomerates.

[0011] The screen drum wall advantageously has a cylindrical or conical shape. This allows for a particularly simple and cost-effective design of the device. A conical shape is advantageous in that the feed material is conveyed along the screen drum wall to one end of the drum due to centrifugal forces.

[0012] The central longitudinal axis of the screening drum can advantageously be arranged vertically and orthogonally to the screening drum base. The feed material is pressed against the screening drum wall by the horizontally acting centrifugal force and the vertically acting gravity, evenly distributed in the circumferential direction, and discharged at the discharge end. This achieves a particularly homogeneous drying result. Furthermore, this arrangement of the central longitudinal axis enables a particularly simple design of the device, in particular a simple arrangement of the feed device.

[0013] In a further advantageous manner, the feed device can be designed such that the feed material can be fed to the screening drum by gravity and / or by a conveyor. Depending on the arrangement of the feed device, the feed material can be fed to the screening drum solely by gravity. This results in a particularly simple and cost-effective design. Furthermore, it is conceivable for the feed device to have a conveyor to feed the feed material at least partially against gravity or to prevent clogging of the feed device.

[0014] The feed device can also comprise a hollow profile, with the hollow profile extending into the screening drum from the discharge side. The closed profile makes it particularly easy for the feed material to be fed into the screening drum at the bottom of the screening drum, where it only mixes with the feed material already in the screening drum.

[0015] Furthermore, it is conceivable for at least one conveying element to be designed as a screw conveyor or a guide vane. A rotating screw conveyor enables the feed material to be conveyed particularly evenly towards the discharge side and circulated at the same time. The longitudinal axis of the screw conveyor is preferably arranged parallel to the central longitudinal axis of the screening drum. To improve conveying and circulation, the screw conveyor can also have a direction of rotation opposite to that of rotation of the screening drum. Designing a conveying element as a guide vane represents a particularly simple design for the conveying device. In contrast to a screw conveyor, continuous operation of the conveying element by means of a drive is not required. The guide vane is inclined in such a way that the feed material is conveyed from the screening drum base to the discharge side as a result of the rotation of the screening drum.

[0016] The position of each conveying element in the radial direction relative to the center longitudinal axis of the screening drum can be individually controlled. This allows the feed material to be conveyed to a specific area of ​​the screening drum and ensures similar dwell times for the feed material. This increases the homogeneity of the drying result.

[0017] It is particularly advantageous if the conveying speed and / or conveying direction of each conveying element can be individually controlled. This can be achieved with a conveying element designed as a screw conveyor by adjusting a speed and / or direction of rotation, or with a conveying element designed as a guide vane by adjusting an angle of inclination. This makes it possible to influence the residence time of the feed material. This is particularly advantageous for responding to fluctuating liquid contents of the feed material. Secondly, the circulation of the feed material can be influenced to prevent a liquid barrier from forming in front of the holes in the screen drum wall. It is also conceivable that the feed material is temporarily conveyed back towards the screen drum base to further increase circulation.

[0018] If the conveyor system has at least two conveyor elements, the conveyor elements can advantageously be arranged equidistant from one another or at irregular intervals along the circumference of a circle. The center of the circle lies on the central longitudinal axis of the screening drum. The conveyor elements of the conveyor system can be positioned along the circumference in a targeted manner to prevent imbalance. This prevents unwanted oscillations or vibrations of the screening drum, which could, for example, negatively impact the drying result or the service life of the screening drum bearings.

[0019] To equalize the feed material at the screen drum base, the conveying device can comprise at least one circulating element. Preferably, the circulating element is designed as a paddle wheel that is rotatable about the central longitudinal axis of the screen drum and is arranged on the screen drum base.

[0020] In a further advantageous manner, at least one cleaning element can be arranged inside and / or at least one cleaning element outside the screening drum in such a way that the screening drum wall can be acted upon. This prevents the holes in the screening drum wall from becoming clogged with feed material or impeding liquid drainage. Particularly advantageously, at least one cleaning element is designed as a brush, an elastic scraper, or a nozzle lance, preferably operable with compressed air and / or liquid. A brush and an elastic scraper are a particularly simple and robust means of cleaning. Particularly for feed material with very small particles, the use of a nozzle lance can be advantageous over that of a brush or an elastic scraper.

[0021] It is also conceivable for the position of each cleaning element to be individually adjustable radially relative to the center longitudinal axis of the screening drum. This allows the position of the cleaning elements to be adjusted depending on the nature of the feed material, thus improving the cleaning result.

[0022] The screening drum can be mounted on the bottom of the screening drum and / or on the discharge side. Depending on the design of the device, it may be advantageous to mount the bearings on the bottom of the screening drum or on the discharge side. For larger screening drums, mounting on both sides may be necessary to minimize unwanted radial or longitudinal movement of the screening drum. Furthermore, it is conceivable that the screening drum mounting includes an elastic clamp and / or a damping device to reduce unwanted vibrations.

[0023] In a further advantageous manner, the discharge device can have an attachment with a flange-like collar enclosing the screening drum, an attachment wall, and an attachment cover, wherein at least one opening is arranged in the attachment wall and wherein the attachment wall at least partially encloses the screening drum wall. As a result, the feed material, which is discharged in the radial and tangential direction as a result of the centrifugal forces, is collected and ejected from the device through the opening. In a particularly advantageous manner, the attachment wall can have a cylindrical shape, and the discharge device can comprise an annular ejection wheel arranged in the attachment. The ejection wheel can be rotatable about the central longitudinal axis of the screening drum and have at least one transport blade. The at least one transport blade can be designed such that the feed material discharged on the discharge side can be fed to the at least one opening.This prevents feed material from accumulating in the discharge device and not being ejected from the opening.

[0024] It is also conceivable to provide a collecting device for collecting and draining the separated liquid, with the collecting device at least partially enclosing the sieve drum. This prevents the separated liquid from being thrown out of the sieve drum in an uncontrolled manner.

[0025] The method according to the invention utilizes the device according to the invention. It is characterized in that the feed material is fed to the screening drum by the feed device at the bottom of the screening drum, is conveyed to the discharge side by the conveying device, wherein the screening drum rotates about its central longitudinal axis and thereby discharges the liquid, and the feed material is discharged at the discharge side due to centrifugal forces and is removed by the discharge device.

[0026] This makes it possible to implement a drying process with continuous supply and removal of the feed material.

[0027] There are now various possibilities for advantageously embodying and developing the teaching of the present invention. For this purpose, reference is made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of preferred embodiments of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawing, generally preferred embodiments and developments of the teaching are also explained. The drawing shows: Fig. 1, an embodiment of a device according to the invention in a schematic representation with a spatial view,

[0028] Fig. 2 shows the embodiment of Fig. 1 in a schematic, sectional view with a spatial view,

[0029] Fig. 3 shows the embodiment of Fig. 1 in a further schematic, sectional view with a side view, and

[0030] Fig. 4 shows the embodiment from Fig. 1 in a further schematic, sectional view with a top view.

[0031] Fig. 1 shows a device according to the invention. It comprises a screening drum 1 with a screening drum base 2, a cylindrical screening drum wall 3, and a discharge side 4. The screening drum 1 rotates about its central longitudinal axis 5, which is arranged orthogonally to the screening drum base 2 and vertically. In this embodiment, the screening drum 1 is arranged on a base plate 6, with a hollow profile support 7 with a base foot being attached to each of the four corner areas of the base plate 6. A drive 8 is arranged on the side of the device, which initiates the rotation of the screening drum 1 and keeps the screening drum 1 moving.

[0032] A discharge device 9 for discharging the feed material is arranged on the discharge side 4, which is positioned at the top in this exemplary embodiment. This device comprises an attachment with a flange-like collar 10 enclosing the screening drum 1, a cylindrical attachment wall 11, and an attachment cover 12. An opening 13 is arranged in the attachment wall 11, through which the feed material is ejected from the device. The attachment cover 12 comprises a circular plate 14, to which a feed device 15 with a funnel-shaped upper part and three conveying elements 16 are fixed. The conveying elements 16 each have an individually controllable drive arranged on the circular plate 14. The exemplary embodiment of the device according to the invention further comprises a collecting device 17 for collecting and discharging the separated liquid.The collecting device 17 has a cylindrical wall 18 that drains the liquid downward. The liquid is then collected and drained away beneath the screening drum 1. Fig. 3 shows that the wall 18 partially encloses the screening drum 1 and is secured at the bottom to the base plate 6 and at the top to the flange-like collar 10. Furthermore, the wall 18 of the collecting device 17 includes an inspection flap 19 with a transparent panel.

[0033] Figures 2 and 3 show that, in addition to the funnel-shaped upper part, the feed device 15 comprises a hollow profile 20 that extends from the discharge side 4 into the screening drum 1. The lower end of the hollow profile 20 represents the feed opening, from which the feed material enters the screening drum 1 at the screening drum base 2. The three conveying elements 16 are each designed as a screw conveyor 16a, which is arranged in the screening drum. Furthermore, a circulating element 21 is arranged on the screening drum base 2. This circulating element 21 is designed as a paddle wheel that can rotate about the central longitudinal axis 5 of the screening drum 1.

[0034] The discharge device 9 comprises an annular discharge wheel 22 arranged in the attachment, which is rotatable about the central longitudinal axis 5 of the screening drum 1 and has several transport blades. The discharge wheel 22 is arranged on the discharge side 4 of the screening drum 1. The rotating discharge wheel 22 feeds the feed material to the opening 13.

[0035] From Fig. 3, it can be seen that the bearing 23 of the screening drum 1 is realized via a shaft 24 arranged along the center axis 5. The screening drum base 2 is fixed to the shaft 24, and the shaft 24 is mounted at the bottom in the base plate 6.

[0036] Fig. 4 shows the embodiment of the device according to the invention in a top view. The device is shown transversely to the central longitudinal axis 5 and in section below the discharge device 9, revealing the three conveyor screws 16, the rotatable paddle wheel of the circulating element 21, and the hollow profile 20. In Fig. 4, the directions of rotation of the conveyor screws 16a and the screening drum 1 are also indicated by arrows. In this embodiment, the conveyor screws 16a rotate in a direction opposite to the direction of rotation of the screening drum 1 to improve the conveying and circulation of the feed material.

[0037] With regard to further advantageous embodiments of the device according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetition.

[0038] Finally, it should be expressly pointed out that the embodiment of the device according to the invention described above serves only to explain the claimed teaching, but does not limit it to the embodiment.

[0039] List of reference symbols

[0040] 1 screening drum

[0041] 2 Screen drum bottom

[0042] 3 Screen drum wall

[0043] 4 Discharge side

[0044] 5 Central longitudinal axis

[0045] 6 Base plate

[0046] 7 Hollow profile support

[0047] 8 Drive of the screening drum

[0048] 9 Discharge device

[0049] 10 Flange-like collar

[0050] 11 Add-on wall

[0051] 12 top lids

[0052] 13 Opening in the top wall

[0053] 14 Circular plate

[0054] 15 Feeding device

[0055] 16 Conveyor element

[0056] 16a Conveyor screw

[0057] 17 Reception facility

[0058] 18 Wall of the collecting device

[0059] 19 Inspection flap

[0060] 20 hollow profile

[0061] 21 Circulation element

[0062] 22 Ejection wheel

[0063] 23 Storage

[0064] 24 Wave

Claims

Claims 1. Device for separating a liquid from a feed material, in particular ground material or granulate made of plastic, with a sieve drum (1) comprising a sieve drum base (2), a sieve drum wall (3) and a discharge side (4) opposite the sieve drum base (2), with a feed device (15) for feeding the feed material into the sieve drum (1) and with a discharge device (9) arranged on the discharge side (4) of the sieve drum (1) for discharging the feed material separated from the liquid, wherein the sieve drum (1) rotates about its central longitudinal axis (5) and in the process discharges the liquid, characterized in that the feed device (15) has a feed opening arranged on the sieve drum base (2) and in that a conveying device with at least one conveying element (16) for conveying the feed material to the discharge side is arranged in the sieve drum (1).

2. Device according to claim 1, characterized in that the sieve drum wall (3) has a cylindrical or a conical shape.

3. Device according to claim 1 or 2, characterized in that the central longitudinal axis (5) of the screening drum (1) is arranged orthogonally to the screening drum base (2) and vertically.

4. Device according to one of claims 1 to 3, characterized in that the feeding device (15) is designed such that the feed material can be fed to the screening drum (1) by gravity and / or by a conveying means.

5. Device according to one of claims 1 to 4, characterized in that the feed device comprises a hollow profile (20), wherein the hollow profile (20) projects from the discharge side (4) into the screening drum (1).

6. Device according to one of claims 1 to 5, characterized in that at least one conveying element (16) is designed as a conveyor screw (16a) or as a guide vane.

7. Device according to one of claims 1 to 6, characterized in that a position of each conveying element (16) is individually adjustable in the radial direction relative to the central longitudinal axis (5) of the screening drum (1).

8. Device according to one of claims 1 to 7, characterized in that the conveying speed and / or the conveying direction of each conveying element (16) can be individually regulated, preferably by adjusting a speed and / or direction of rotation when the conveying element (16) is designed as a conveyor screw (16a) or by adjusting an angle of inclination when the conveying element (16) is designed as a guide vane.

9. Device according to one of claims 1 to 8, characterized in that at least two conveying elements (16) are arranged, wherein the conveying elements (16) are arranged equidistant from one another or at irregular intervals from one another along a circumferential line of a circle, wherein the center of the circle lies on the central longitudinal axis (5) of the screening drum (1).

10. Device according to one of claims 1 to 9, characterized in that the conveying device comprises at least one circulating element (21) for distributing the feed material, preferably wherein the circulating element (21) is designed as a paddle wheel rotatable about the central longitudinal axis (5) of the screening drum (1).

11. Device according to one of claims 1 to 10, characterized in that at least one cleaning element inside and / or at least one cleaning element outside the screening drum (1) is / are arranged in such a way that the screening drum wall (3) can be acted upon.

12. Device according to claim 11, characterized in that at least one cleaning element is designed as a brush, as an elastic wiper or as a nozzle lance, preferably operable with compressed air and / or liquid.

13. Device according to claim 11 or 12, characterized in that a position of each cleaning element can be individually regulated in the radial direction relative to the central longitudinal axis (5) of the screening drum (1).

14. Device according to one of claims 1 to 13, characterized in that a bearing (23) of the screening drum (1) is arranged on the screening drum base (2) and / or on the discharge side (4).

15. Device according to claim 14, characterized in that the bearing (23) of the screening drum (1) comprises an elastic clamping and / or a damping means.

16. Device according to one of claims 1 to 15, characterized in that the discharge device (9) comprises an attachment with a flange-like collar (10) surrounding the screening drum (1), an attachment wall (11) and an attachment cover (12), wherein at least one opening (13) is arranged in the attachment wall (11) and wherein the attachment wall (11) at least partially surrounds the screening drum wall (3).

17. Device according to claim 16, characterized in that the attachment wall (11) has a cylindrical shape and the discharge device (9) comprises an annular ejection wheel (22) arranged in the attachment, wherein the ejection wheel (22) is rotatable about the central longitudinal axis (5) of the screening drum (1) and has at least one transport blade, wherein the at least one transport blade is designed such that the feed material discharged on the discharge side (4) can be fed to the at least one opening (13).

18. Device according to one of claims 1 to 17, characterized in that a collecting device (17) is arranged for collecting and removing the separated liquid, wherein the collecting device (17) at least partially encloses the sieve drum (1).

19. A method for separating a liquid from a feed material, in particular from ground material or granulate made of plastic, using a device according to one of claims 1 to 18, characterized in that the feed material is fed by the feed device (15) to the sieve drum (1) at the sieve drum base (2), is conveyed to the discharge side (4) by the conveying device, the sieve drum (1) rotating about its central longitudinal axis (5) and in the process discharging the liquid, and that the feed material is discharged at the discharge side (4) as a result of centrifugal forces and is discharged by the discharge device (9).

Images