Flat screening machine

Abstract

The invention relates to a plansifter (1) comprising at least one compartment (2, 3), according to the invention, the compartment (2, 2 ') is arranged in the interior region (2b) of the compartment (2, 2') and a drive module (3) for generating a vibratory and / or oscillating movement of the compartment (2, 2 '), a screen stack (5) is arranged in the interior region (2b) of the compartment (2, 2'), which screen stack comprises at least one screen, preferably 2 to 32 screens, more preferably 10 to 32 screens, particularly preferably 20 to 32 screens, and the compartment (2, 2 ') has an outlet frame (9) arranged in the bottom region (2c) of the compartment (2, 2'). The invention also relates to an outlet frame for a plansifter and to a method for screening material in the plansifter (1).

Description

Technical Field

[0001] The invention relates to a flat screen machine comprising an enlarged screen area. Background Art

[0002] Screens are widely used in industrial applications where materials need to be separated or classified according to particle size. As an example, flat screens may be mentioned.

[0003] In mills, in particular grain mills, flat screens are widely used for screening flour products or granular products. An example is the Sirius MPAK flat screen from Bühler. The flat screen has a lockable screen module (also referred to herein as a compartment) having at least one stack of screen discs arranged one on top of the other, in which different mesh sizes of the screen discs can be selected throughout the screen stack in order to classify the product within the desired particle size range. For the screening movement, the flat screen is set in a uniform oscillating motion by means of an unbalanced drive. Typically, the drive is arranged in a separate drive module, which is arranged near the compartment.

[0004] Subsequently, each fraction of the screened material that has been separated from each other in the stack of screen trays is directed to an outlet frame. The outlet frame is located in the lower part of the inner area of ​​the corresponding compartment and directs each fraction to the appropriate outlet of the screen module. The outlet frame is usually made of plastic material such as polyurethane.

[0005] In known flat screen machines, several compartments are usually arranged in two rows in an even number, wherein the drive module is arranged between the two rows, as described, for example, in DE-2 256 307 A1. In addition, according to EP-A-1 396 289 A1, an arrangement structure with one drive module between two blocks of four screen modules (compartments) is known.

[0006] The above-mentioned prior art flat screen machines are not yet optimal.

[0007] The outlet frame in the lower part of the inner area of ​​each compartment takes up valuable space, which is therefore not available for arranging additional sieve trays. Designing the outlet frame as a plastic component involves the risk of introducing plastic material into the product flow, which is undesirable. A plastic outlet frame also does not contribute to achieving the structural integrity of the flat screen machine, as it does not provide the necessary mechanical support. Summary of the invention

[0008] The problem underlying the present invention is to provide a plansifter which overcomes the above-mentioned disadvantages of the prior art.

[0009] The flat screen machine according to claim 1 solves the above-mentioned problem.

[0010] In detail, the present invention relates to a flat screen machine, which includes at least one compartment and a drive module for causing the compartment to generate vibration and / or swinging motion, wherein the at least one compartment has a frame forming outer walls of a top area, an inner area and a bottom area, wherein at least one inlet is provided in the top area and at least one outlet is provided in the bottom area, wherein a screen stack is provided in the inner area, the screen stack includes at least one screen, preferably 2 to 32 screens, more preferably 10 to 32 screens, and particularly preferably 20 to 32 screens, characterized in that the compartment has an outlet frame arranged in the bottom area.

[0011] The invention is based on the concept of arranging the outlet frame in the bottom area of ​​the compartment of the flat screen machine instead of in the inner area. This makes it possible to arrange an additional screen in the inner area of ​​the compartment and to advantageously utilize the bottom area of ​​the compartment.

[0012] In the prior art, the top area, the inner area and the bottom area of ​​the plansifter are different areas. The inner area is a hollow space in the compartment, which is separated from the top area and the bottom area by a partition wall. In the partition wall, there are openings leading from the top area to the inner area and from the inner area to the bottom area. In the hollow space of the inner area, both the screen stack and the outlet frame are arranged.

[0013] The flat screen machine according to the present invention differs from a conventional flat screen machine only in the outlet frame. Therefore, the design of the flat screen machine according to the present invention is basically as described above. However, the outlet frame is not arranged in the hollow space of the inner area, but in the bottom area. According to the present invention, preferably there is no longer a partition wall between the inner area and the bottom area. However, it should be understood that the bottom area is still outside the hollow space of the inner area, but is not part of the inner space.

[0014] The flat screen machine according to the invention comprises a compartment serving as a screen module, and a screen stack consisting of screens is arranged in the compartment.According to the invention, any screen used in conventional flat screen machines can be used in the flat screen machine of the invention.

[0015] A screen stack is arranged in the inner region of each compartment of the flat screen machine. The screen stack comprises at least one screen, preferably 2 to 32 screens, more preferably 10 to 32 screens, particularly preferably 20 to 32 screens. The design and operation of the screens are known and will not be discussed in detail here.

[0016] According to a preferred embodiment of the present invention, the flat screen machine comprises two rows of compartments, each row consisting of at least one compartment, preferably consisting of 2 to 10 compartments. However, other compartment arrangements may also be used. According to the preferred embodiment of the present invention, the drive module is arranged between the two rows. The drive module is used to cause the compartments to vibrate and / or swing. Preferably, the drive module consists of at least one drive unit. Preferably, one drive unit is arranged between two compartments and can cause the two compartments to vibrate and / or swing.

[0017] As is generally known, the flatscreen machine is arranged on poles which can be connected, for example, to the ceiling of the hall in which the flatscreen machine is located. The flatscreen machine is thus a cantilever flatscreen machine, which allows the compartments to generate a vibrating and / or oscillating movement.

[0018] According to a preferred embodiment of the invention, the flat screen machine is designed so that each row is of modular design, so that compartments can be added to or removed from the row.

[0019] Each compartment of the flat screen machine of the present invention has a frame forming the outer walls of the top area, the inner area and the bottom area.Preferably, each compartment has a cubic structure in which the above three areas are arranged.

[0020] In the top region, at least one inlet is provided. The inlet is used to introduce the material to be screened into the compartment. According to the invention, the number of inlets provided in each compartment is limited only by the available space. Typically, 1 to 5 inlets are provided, preferably 2 to 4 inlets are provided. These inlets can be connected to a feed line, via which the material can be conveyed to the compartment. The material entering the compartment from the top region through the inlet falls under gravity into an inner region provided below the top region. In the inner region, the above-mentioned screen stack is provided.

[0021] According to a preferred embodiment of the invention, the compartment comprises a door in the front wall, making it possible to access the inner area of ​​the flat screen machine. This makes it possible to insert and / or replace the screen in the inner area of ​​the compartment. The door should be dimensioned so that when the door is opened, it is sufficient to access the inner area of ​​the compartment.

[0022] In the bottom region, at least one outlet is provided. The outlet is used to remove the screened and classified material from the compartment. According to the invention, the number of outlets provided on each compartment is limited only by the available space. Typically, 1 to 10 outlets are provided, preferably 2 to 8 outlets are provided, more preferably 3 to 6 outlets are provided. These outlets can be connected to a feed line such as a conveying line, through which the material can be transported away from the compartment.

[0023] In a flat screen machine according to the prior art, the outlet frame is the area in the lower part of the inner area of ​​the compartment, in which an opening to the outlet and a channel ramp for guiding the screened material to the opening are arranged. In addition, (non-inclined) side walls are provided which divide this area into recesses. These components are separate and independent from each other.

[0024] In contrast, according to the invention, the outlet frame is arranged in the bottom region of the compartment, i.e. in a region separated from the inner region. This provides more space in the inner region of the compartment, which can be used to arrange additional screens (which otherwise can only be achieved by increasing the size of the flat screen machine, which is not desirable). As a result, the screening efficiency of the flat screen machine of the invention is improved compared to conventional flat screen machines.

[0025] According to a preferred embodiment of the present invention, an outlet frame is provided which is composed of a single piece, in which at least one recess is provided, the recess comprising a bottom surface with an opening and inclined side walls.

[0026] Therefore, the present invention also relates to an outlet frame for a flat screen machine, which outlet frame consists of a single piece, preferably made of metal material, wherein the single piece includes at least one recess, preferably 2 to 10 recesses, more preferably 3 to 6 recesses, wherein each recess includes an inclined side wall and an opening in the bottom surface of the recess, the side wall being inclined towards the opening so that material can be moved across the side wall into the opening.

[0027] Preferably, the outlet frame is made of a metallic material, preferably stainless steel. This avoids the use of plastic parts in the flat screen machine, thus eliminating the risk of introducing plastic material into the product flow, thereby improving the hygienic properties of the flat screen machine of the invention. Furthermore, the service life of an outlet frame of metallic material is generally longer than an outlet frame of plastic material. Finally, the metallic outlet frame of the invention improves recyclability.

[0028] Furthermore, by providing an outlet frame made of a strong and rigid material in the bottom region of the compartment, the structural support of the compartment is increased. In the case where the outlet frame is preferably stainless steel, the bottom region of the compartment becomes more rigid.

[0029] According to a preferred embodiment of the invention, the outlet frame is a deep-drawn part, preferably a deep-drawn metal sheet.

[0030] Deep drawing is a known technique for preparing metal parts of a desired shape, which will not be discussed in detail herein. By means of deep drawing, the one-piece outlet frame with a recess according to the present invention can be effectively prepared.

[0031] According to another preferred embodiment of the invention, the outlet frame is made by additive manufacturing. In additive manufacturing, data computer-aided design (CAD) software or a 3D object scanner is used to guide hardware to deposit material, preferably layer by layer, into a precise geometric shape. A preferred variant of additive manufacturing is 3D printing. Additive manufacturing and materials for additive manufacturing are known.

[0032] The outlet frame according to a preferred embodiment of the present invention comprises at least one notch, preferably 2 to 10 notches, more preferably 3 to 6 notches. These notches are intended to accommodate the fraction of the material to be screened in the screen stack of the corresponding compartment of the flat screen machine of the present invention. As is well known, the screen stack of the flat screen machine is composed of vertically arranged screens with different mesh sizes, wherein the mesh size of the screen is generally gradually reduced from the top to the bottom of the screen stack. The material with a particle size smaller than the mesh size of the corresponding screen falls onto the collecting tray through the screen, and the material is transported from the collecting tray to the outlet located at one side of the screen by the vibration and / or swinging movement of the screen during operation under the support of the swinging movement of the screen cleaner between the screen and the collecting tray, and the material is guided to the notch of the outlet frame or subsequently returned to the inside of the screen stack through the outlet, and the particles with a particle size larger than the mesh size of the corresponding screen are transported to the outlet located at one side of the screen by the vibration and / or swinging movement of the screen during operation, and the particles are guided to the notch of the outlet frame or subsequently returned to the inside of the screen stack through the outlet. By repeatedly separating the material on different screens, different material fractions are obtained, which are conducted to separate recesses of the outlet frame of the invention, for example by means of lines arranged in the flat screen machine.

[0033] In a preferred embodiment of the outlet frame of the invention, each recess comprises an inclined side wall and an opening in the bottom surface of the recess, the side wall being inclined towards the opening so that the material can be moved across the side wall into the opening. The material entering the recess from above is then transferred to the opening in the bottom surface of the recess. When installed in the flat screen machine of the invention, each opening in the recess of the outlet frame is connected to an outlet fluid in the bottom area of ​​the flat screen machine. Thus, the material is reliably transferred out of the flat screen machine through the opening in the outlet frame and the outlet of the compartment. Outside the compartment, the material can be transported away from the flat screen machine, for example by known conveying devices.

[0034] According to a preferred embodiment of the invention, the isolating portion is arranged outside the bottom surface and / or the inclined side wall of the outlet frame, preferably bonded to the bottom surface and / or the inclined side wall of the outlet frame. Any material that can isolate the outlet frame from environmental conditions such as temperature or humidity can be used to achieve this purpose. Preferably, the isolating portion in the form of a layer is provided, more preferably the isolating portion in the form of an injection molded layer is provided.

[0035] According to a preferred embodiment of the invention, the outlet frame is mechanically fixed, preferably releasably fixed, in the bottom area of ​​the compartment. More preferably, the mechanical fixing is provided by screw joints, preferably by eight screw joints arranged in the four corners of the bottom area. Preferably, the bottom area is made of metal such as cast iron.

[0036] In particular, when using the above-mentioned one-piece outlet frame, this fixing provides an enhanced structural support in the bottom area of ​​the compartment. The rigidity of the bottom area is increased, wherein the mechanical loads are borne by the mechanically fixed outlet frame. This also reduces the weight of the flat screen machine, because the mechanically fixed outlet frame replaces other parts that would otherwise need to bear the mechanical loads.

[0037] With the flat sifter according to the invention, different types of materials can be sieved. For example, flour products or granular products such as cereals can be mentioned. However, sugars or chemicals can also be sieved well in the flat sifter according to the invention.

[0038] The present invention also relates to a method for screening material in the above-mentioned flat screen machine, the method comprising the following steps:

[0039] a) introducing the material to be screened into the inlet of the compartment of the flat screen machine,

[0040] b) screening material using a screen stack arranged in an interior region of the compartment,

[0041] c) Removal of the screened material via an outlet frame arranged in the bottom region of the compartment and the outlet of the compartment.

[0042] The details of the method have been explained above.

[0043] There is a difference between sieving and sifting. In sieving, particles are strictly separated from each other due to their different particle sizes, so that smaller particles can pass through the sieve openings of a specific size, while larger particles are blocked by the sieve. In sieving, particles are separated from each other based on their size, shape and density by forming strata on the sieve due to the circular motion of the sieve and product flow.

[0044] Preferably, in step c), material is removed by moving material downwardly across an inclined side wall of at least one recess of the outlet frame to an opening in a bottom surface of the recess of the outlet frame, the side wall being inclined towards the opening so that the material is moved across the side wall into the opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The invention will be explained in more detail hereinafter with reference to non-limiting examples and the accompanying drawings.

[0046] Figure 1 A perspective view of a plansifter according to the prior art is shown.

[0047] Figure 2 The lower part of a compartment of a planscrete machine according to the prior art is shown.

[0048] Figure 3 A perspective view of an embodiment of a flat screen machine according to the invention is shown.

[0049] Figure 4 An embodiment of an outlet frame according to the invention in a flat screen machine is shown.

[0050] In the drawings, like reference numerals denote like components. DETAILED DESCRIPTION

[0051] exist Figure 1 In FIG. 1 , an embodiment of a prior art flat screen machine 1 is shown. The flat screen machine 1 comprises compartments 2, 2' which serve as screen modules. Figure 1 In the embodiment of the present invention, two rows of compartments 2, 2' are provided, wherein each row consists of three compartments 2, 2'. Between these rows of compartments 2, 2', a drive module 3 is arranged. Figure 1 In the embodiment of the present invention, the two compartments 2, 2' can be set into a vibrating or oscillating motion by means of a drive unit arranged between them.

[0052] Each compartment 2, 2' comprises a top area 2a, an inner area 2b and a bottom area 2c which are separated from each other, and is provided with a door 4, 4'. Figure 1 In the embodiment shown, for the sake of schematic illustration, one door 4 has been removed from a compartment 2', so that the entire screen stack 5 arranged in the inner region 2b of said compartment 2' is visible.

[0053] In the flat screening machine 1 , as is generally known, the screen stack 5 comprises a screen frame equipped with an insert frame. Due to the presence of the outlet frame 9 in the lower part of the inner area 2b of the compartments 2, 2', the number of screens that can be arranged across the height of the inner area of ​​the flat screening machine 1 is limited.

[0054] The flat screen machine 1 has a rotary drive (not shown) in the drive module 3 , which sets all screens in the compartments 2 , 2 ′ into a circular motion. To achieve this, the flat screen machine 1 is suspended on a rod 8 as a cantilever.

[0055] Material is fed into the screen stack 5 in each compartment 2, 2' via an inlet 6, 6', 6" provided in the top region 2a of each compartment 2, 2', and the classified material is discharged via an outlet 7, 7', 7" provided in the bottom region 2c of each compartment 2, 2'. Figure 1In the embodiment of , one inlet 6, 6', 6" and two outlets 7, 7', 7" are assigned to each compartment 2, 2'. However, it should be understood that the number of inlet ports and outlet ports assigned to each compartment 2, 2' may be adjusted if desired or necessary.

[0056] Figure 2 Shown according to Figure 1 The lower part of the two compartments 2, 2' of the prior art flat screen machine 1. In the left compartment 2, a screen stack 5 is arranged in the inner area of ​​the compartment 2. In addition, an outlet frame 9 is also arranged below the screen stack 5 in the inner area 4 of the compartment 2. The outlet frame 9 includes a recess 9a, which leads to an opening 9c, which is connected to the outlet 7, 7', 7" (not shown in Figure 2 In addition, as can be best seen in the right compartment 2' (where the screen stack 5 and the outlet frame 9 are not inserted into the interior area 2b of said compartment 2'), a channel ramp 9b is provided for guiding the screened material into the opening 9c. Figure 2 As can be seen in the figure, the bottom region 2c of each compartment 2, 2' is provided with only openings 9c. The bottom region 2c is separated from the inner region 2b, which is provided with a hollow space for inserting the screen stack 5.

[0057] Figure 3 An embodiment of the flat screen machine 1 according to the present invention is shown. Figure 1 Compared to the prior art flat screen machine, the outlet frame 9 is now arranged in the bottom area 2c of each compartment 2, 2' instead of in its inner area 2b. Here too, the bottom area 2c is separated from the inner area 2b. In the bottom area 2c, no screen may be arranged. However, since the hollow space of the inner area 2b no longer has to accommodate the outlet frame 9, there is free space for inserting an additional screen into the inner area 2b.

[0058] Figure 4 The plan screen machine 1 according to the present invention is shown in more detail. Figure 3 The outlet frame 9 is arranged in the bottom area 2c of the compartment 2. Therefore, the inner area 2b does not include the outlet frame 9 and can accommodate more screens.

[0059] Preferably, the outlet frame 9 is made of a metal material such as stainless steel to provide structural support for the flat screen machine.

[0060] The outlet frame 9 comprises recesses 9a into which the screened material is introduced. The recesses 9a each comprise an opening 9c in its bottom surface. The openings 9c are aligned with the outlets 7, 7', 7" (shown in FIG. Figure 3) are connected so that the screened and classified material passes through the opening 9c and the outlet 7, 7', 7" (shown in Figure 3 Middle) Leave compartment 2.

[0061] Each recess 9a comprises an inclined side wall 9d which directs the screened material entering the recess 9a to a corresponding opening 9c in the bottom surface of the recess 9a.

[0062] exist Figure 4 In the embodiment of the present invention, the partition 9e is arranged below the bottom surface and / or the inclined side wall 9d. Preferably, the partition is bonded to the outlet frame 9. Figure 4 In the embodiment of the present invention, the outlet frame 9 is composed of a single piece, preferably composed of a metal material, more preferably composed of stainless steel. Particularly preferably, the single-piece outlet frame (9) is a deep-drawn part, preferably a deep-drawn metal sheet.

[0063] like Figure 4 As shown, the outlet frame 9 is provided with screws 9f for fixing the side wall 9d to the bottom area 2c of the compartment 2, 2'. Figure 4 Not shown in the drawing, the outlet frame 9 is mechanically fixed, preferably releasably fixed, to the bottom area 2c of the compartment 2, 2' by screw joints, preferably by eight screw joints arranged in the four corners of the bottom area 2c of the compartment 2, 2'.

Claims

1. A flat screen machine (1), comprising at least one compartment (2, 2') and a drive module (3) for causing the compartment (2, 2') to produce a vibrating and / or oscillating motion, in, The at least one compartment (2, 2') has a frame forming outer walls of a top region (2a), an inner region (2b) and a bottom region (2c), wherein at least one inlet (6, 6', 6") is provided in the top region (2a) and at least one outlet (7, 7', 7") is provided in the bottom region (2c), wherein a screen stack (5) is provided in the inner region (2b), the screen stack comprising at least one screen, preferably 2 to 32 screens, more preferably 10 to 32 screens, particularly preferably 20 to 32 screens, It is characterized in that The compartment (2, 2') has an outlet frame (9) which is arranged in the bottom region (2c).

2. The flat screen machine according to claim 1, characterized in that: The outlet frame (9) is made of metal material, preferably stainless steel.

3. The flat screen machine according to claim 2, characterized in that: The outlet frame (9) is a deep drawn part, preferably a deep drawn metal sheet.

4. The flat screen machine according to any one of claims 1 to 3, characterized in that: The outlet frame comprises at least one notch (9a), preferably 2 to 10 notches, more preferably 3 to 6 notches.

5. The flat screen machine according to claim 4, characterized in that: Each recess (9a) comprises an inclined side wall (9d) and an opening (9c) in the bottom surface of the recess (9a), the side wall (9d) being inclined towards the opening (9c) so that material can be moved across the side wall (9d) into the opening (9c).

6. The flat screen machine according to claim 5, characterized in that: Each opening (9c) in the recess (9a) of the outlet frame (9) is in fluid connection with an outlet (7, 7', 7") in the bottom region (2c) of the flat screen machine (1).

7. The flat screen machine according to any one of claims 1 to 6, characterized in that: A partition (9e) is provided outside the bottom surface and / or the inclined side wall (9d) of the outlet frame (9), and is preferably bonded to the bottom surface and / or the inclined side wall of the outlet frame.

8. The flat screen machine according to any one of claims 1 to 7, characterized in that: The outlet frame (9) is mechanically fixed, preferably releasably fixed, in the bottom region (2c) of the compartment (2, 2').

9. The flat screen machine according to claim 8, characterized in that: The mechanical fixing is provided by screw joints (9f), preferably by eight screw joints arranged in the four corners of the bottom area (2c) of the compartment (2, 2').

10. The flat screen machine according to any one of claims 1 to 9, characterized in that: The flat screen machine (1) comprises two rows of compartments (2, 2'), each row consisting of at least one compartment (2, 2'), preferably 2 to 10 compartments (2, 2'), wherein the drive module (3) is arranged between the two rows.

11. The flat screen machine according to claim 10, characterized in that: Each row is of modular design, so that compartments (2, 2') can be added to or removed from the row.

12. The flat screen machine according to any one of claims 1 to 11, characterized in that The at least one compartment comprises a door (4, 4') in a front wall, thereby making the inner area (2b) of the flatscreen machine (1) accessible.

13. An outlet frame (9) for a flat screen machine (1), the outlet frame (9) being composed of a single piece, preferably made of metal material, wherein: The integral part comprises at least one recess (9a), preferably 2 to 10 recesses, more preferably 3 to 6 recesses, wherein each recess (9a) comprises an inclined side wall (9d) and an opening (9c) in the bottom surface of the recess (9a), the side wall (9d) being inclined toward the opening (9c) so that material can be moved across the side wall (9d) into the opening (9c).

14. A method for screening material in a flat screen machine (1) according to any one of claims 1 to 12, the method comprising the following steps: a) introducing the material to be screened into the inlet (6, 6', 6") of the compartment (2, 2') of the flat screen machine (1), b) screening the material using a screen stack (5) arranged in the inner region (2b) of the compartment (2, 2'), c) removing the screened material through an outlet frame (9) provided in the bottom region (2c) of the compartment (2, 2') and an outlet (7, 7', 7") of the compartment (2, 2').

15. The method according to claim 14, characterized in that In step c), the material is removed by moving the material downwardly across the inclined side wall (9d) of at least one recess (9a) of the outlet frame (9) to reach an opening (9c) in the bottom surface of the recess (9a) of the outlet frame (9), the side wall (9d) being inclined toward the opening (9c) so that the material is moved across the side wall (9d) into the opening (9c).

Images