PLANSIFTER

Abstract

A plansifter comprising at least one compartment and a drive module for putting the compartment into a vibrational and/or oscillating movement, wherein in the inner region of the compartment there is provided a sieve stack comprising at least one sieve, preferably 2-32 sieves, more preferably 10 to 32 sieves, especially preferred 20 to 32 sieves, and the compartment has one outlet frame that is provided in the bottom region of the compartment. The present invention is furthermore related to an outlet frame for a plansifter and to a method for sieving material in said plansifter.

Claims

1. A plansifter comprising at least one compartment and a drive module for putting the compartment into a vibrational and/or oscillating movement, wherein said at least one compartment has a framework of outer walls forming a top region, an inner region and a bottom region, wherein in said top region there is provided at least one inlet and in the bottom region there is provided at least one outlet, wherein the inner region there is provided a sieve stack comprising at least one sieve, preferably 2-32 sieves, more preferably 10 to 32 sieves, especially preferred 20 to 32 sieves, wherein the compartment has one outlet frame that is provided in the bottom region.

2. The plansifter according to claim 1, the outlet frame made of a metallic material, preferably stainless steel.

3. The plansifter according to claim 2, wherein the outlet frame is a deep-drawn part, preferably a deep-drawn metal sheet.

4. The plansifter according to claim 1, wherein the outlet frame comprises at least one pocket, preferably 2 to 10 pockets, more preferably 3 to 6 pockets.

5. The plansifter according to claim 4, wherein each pocket comprises inclined side walls and an opening in the bottom surface of the pocket, the side walls being inclined towards the opening so that material may be moved over the side walls into the opening. (

6. The plansifter according to claim 5, wherein each opening in a pocket of the outlet frame is fluidly connected to an outlet in the bottom region of the plansifter.

7. The plansifter according to claim 1, wherein an insulation is provided outside, preferably glued to, the bottom surface and/or the inclined side walls of the outlet frame.

8. The plansifter according to claim l, wherein the outlet frame is mechanically fixed, preferably releasably fixed, in the bottom region of the compartment.

9. The plansifter according to claim 8, wherein said mechanical fixation is provided by screw joints, preferably by eight screw joints arranged in the four corners of the bottom region of the compartment.

10. The plansifter according to claim 1, wherein the plansifter comprises two rows of compartments, each row consisting of at least one compartment, preferably 2 to 10 compartments, wherein said drive module is arranged between said two rows.

11. The plansifter according to claim 10, wherein each row has a modular design, so that compartments can be added to or removed from a row.

12. The plansifter according to claim 1, wherein said at least one compartment comprises a door in the front wall, allowing access to the inner region of the plansifter.

13. An outlet frame for a plansifter, said outlet frame consisting of one piece, preferably made of a metallic material, wherein said one piece comprises at least one pocket, preferably 2 to 10 pockets, more preferably 3 to 6 pockets, wherein each pocket comprises inclined side walls and an opening in the bottom surface of the pocket, the side walls being inclined towards the opening so that material may be moved over the side walls into the opening.

14. A method for sieving material in a plansifter according to claim 1, comprising the steps: a) introducing material to be sieved into an inlet of a compartment of the plansifter, b) sieving the material using a sieve stack provided in the inner region of said compartment, c) removing the sieved material through an outlet frame provided in the bottom region of said compartment and an outlet of said compartment.

15. The method according to claim 14, the material is removed in step c) by moving downward over inclined side walls of at least one pocket of said outlet frame to an opening in the bottom surface of the pocket of the outlet frame, the side walls being inclined towards the opening so that material is moved over the side walls into the opening.

Description

[0046] The present invention will hereinafter be explained in more detail by reference to non-limiting examples and drawings.

[0047] FIG. 1 shows a perspective view of a plansifter according to the prior art

[0048] FIG. 2 shows the lower part of a compartment of a plansifter according to the prior art

[0049] FIG. 3 shows a perspective view of an embodiment of a plansifter according to the present invention

[0050] FIG. 4 shows an embodiment of an outlet frame according to the present invention in a plansifter.

[0051] In the drawings, the same reference numbers denote the same components.

[0052] In FIG. 1, an embodiment of a plansifter 1 from the prior art is shown. The plansifter 1 comprises compartments 2, 2 acting as sieve modules. In the embodiment of FIG. 1, two rows of compartments 2, 2 are provided, wherein each row is composed of three compartments 2, 2. Between these rows of compartments 2, 2, there is arranged a drive module 3. In the embodiment of FIG. 1, two compartments 2, 2 can be put into vibrational or oscillatory movement by means of a drive unit arranged between them.

[0053] Each compartment 2, 2 comprises a top region 2a, an inner region 2b and a bottom region 2c, which are separate from one another, and is equipped with a door 4, 4. In FIG. 1, for illustration purposes one door 4 is removed from a compartment 2, so that an entire sieve stack 5 arranged in the inner region 2b of said compartment 2 is visible.

[0054] In the plansifter 1, the sieve stack 5 comprises sieve frames equipped with insert frames, as conventionally known. The number of sieves that can be provided over the height of the inner region of the plansifter 1 is limited due to the presence of an outlet frame 9 in the lower part of the inner region 2b of the compartment 2, 2.

[0055] The plansifter 1 has a swing drive (not shown) in the drive module 3 which imposes a circular motion on all the sieves in the compartments 2, 2. For this purpose, the plansifter 1 is suspended as a cantilever on rods 8.

[0056] The material is fed to the sieve stacks 5 in the compartments 2, 2 via inlets 6, 6, 6 provided in the top region 2a of each compartment 2, 2, and the sorted material is discharged via outlets 7, 7, 7 provided in the bottom region 2c of each compartment 2, 2. In the embodiment of FIG. 1, one inlet 6, 6, 6 and two outlets 7, 7, 7 are attributed to each compartment 2, 2. It is understood, however, that the number of inlet ports and outlet ports attributed to each compartment 2, 2 may be adjusted if desired or necessary.

[0057] FIG. 2 shows the lower part of two compartment 2, 2 of the plansifter 1 from the prior art according to FIG. 1. In the left compartment 2, there is arranged a sieve stack 5 in the inner region of the compartment 2. Moreover, in the inner region 4 of the compartment 2, there is also arranged an outlet frame 9, below the sieve stack 5. Said outlet frame 9 comprises pockets 9a, which open into the openings 9c, which are connected to outlets 7, 7, 7 (not shown in FIG. 2). Furthermore, as can be best seen in the right compartment 2 (where no sieve stack 5 and no outlet frame 9 is inserted into the inner region 2b of said compartment 2), channel ramps 9b are provided which serve for guiding the sieved material into the openings 9c. As can be seen in FIG. 2, the bottom region 2c of each compartment 2, 2 only provides the openings 9c. The bottom region 2c is separate from the inner region 2b (which provides a hollow space for insertion of the sieve stack 5).

[0058] FIG. 3 shows an embodiment of a plansifter 1 according to the present invention. As compared to the plansifter from the prior art according to FIG. 1, the outlet frame 9 is now provided in the bottom region 2c of each compartment 2, 2, instead of being provided in the inner region 2b thereof. Also here, the bottom region 2c is separate from the inner region 2b. In the bottom region 2c, no sieves can be provided. However, since the hollow space of the inner region 2b no longer has to take up the outlet frame 9, there is free space for inserting additional sieves into the inner region 2b.

[0059] FIG. 4 shows the bottom region 2c of the plansifter 1 according to the present invention (as shown in FIG. 3) in more detail. The outlet frame 9 is provided in the bottom region 2c of the compartment 2. Thus, the inner region 2b does not comprise said outlet frame 9 and can house more sieves.

[0060] Preferably, the outlet frame 9 is made of a metallic material such as stainless steel, so as to provide structural support to the plansifter.

[0061] The outlet frame 9 comprises pockets 9a into which sieved material is introduced. The pockets 9a each comprise an opening 9c in their bottom surfaces. Said openings 9c are in communicating connection with outlets 7, 7, 7 (shown in FIG. 3) of the compartment 2, so that sieved and sorted material exits the compartment 2 through said openings 9c and outlets 7, 7, 7 (shown in FIG. 3).

[0062] Each pocket 9a comprises inclined side walls 9d that guide sieved material entering a pocket 9a to the respective opening 9c in the bottom surface of the pocket 9a.

[0063] In the embodiment of FIG. 4, an insulation 9e is provided underneath the bottom surface and/or the inclined side walls 9d. Preferably, said insulation to glued to the outlet frame 9. In the embodiment of FIG. 4, the outlet frame 9 consists of one piece, preferably of a metallic material, more preferably stainless steel. Especially preferred, the one-piece outlet frame (9) is a deep-drawn part, preferably a deep-drawn metal sheet.

[0064] As shown in FIG. 4, the outlet frame 9 is provided with screws 9f for securing the side walls 9d to the bottom region 2c of the compartment 2, 2. Furthermore, but not displayed in FIG. 4, said outlet frame 9 is mechanically fixed, preferably releasably fixed, to the bottom region 2c of the compartment 2, 2 by screw joints, preferably by eight screw joints arranged in the four corners of the bottom region 2c of the compartment 2, 2.