HYDROCLONE ARRANGEMENT

Description

[0001] The invention relates to a hydrocyclone arrangement for cleaning a fibrous suspension with several hydrocyclone chambers of circular cross-section, into which an inlet and a light part outlet open at one end and a heavy part separator open at the opposite end, wherein the inlets are connected to a common inlet via a common inlet chamber.

[0002] Hydrocyclones are well suited to concentrate heavy and light particles in fibrous suspensions using centrifugal forces and to discharge them via the outlet or separator.

[0003] They are generally used to remove small metal parts, glass shards and sand, or polystyrene and other lightweight plastic parts.

[0004] The chamber material is subject to high wear, which is why it is usually made of ceramic, a dimensionally stable plastic, or metal. This is especially true due to the high pressure of up to 4 or even 6 bar at the chamber inlet during the cleaning of a fibrous suspension.

[0005] The smaller the diameter of the hydrocyclone chamber, the more efficient the hydrocyclone. Alternatively, low pressure losses can be achieved with the same efficiency. Since the throughput per hydrocyclone decreases, there are efforts to combine several small hydrocyclones, as described in FR 1 476 005 A and US 4 233 160.

[0006] However, the routing of the inlets and the light part outlets poses problems, especially due to the limited space available, when these hydrocyclone arrangements are intended to replace individual hydrocyclones.

[0007] The object of the invention is therefore to simplify the design of such hydrocyclone arrangements.

[0008] According to the invention, the problem was solved by connecting the light part outlets to a common light part discharge via separate discharge lines that lead through the common inlet chamber. The common inlet chamber is connected to the inlets of the hydrocyclone chambers via separate inlet channels. The inlet channel is curved before the inlet and follows the outer circumference of the hydrocyclone chamber.

[0009] The separate outlet lines allow for better distribution of the supplied fiber suspension to the inlets or their inlet channels, and thus also a very compact design.

[0010] The homogeneous distribution of the fiber suspension can be further supported by ensuring that at least one component of the common feed enters the feed chamber, which preferably has a circular cross-section, tangentially. This creates an annular flow within the feed chamber that sweeps across all inlet channels.

[0011] Additionally, guide elements can be installed in the inlet chamber to direct the fiber suspension to the inlet channels. The outlet channels themselves can also be used to redirect the fiber suspension to the inlet channels, either directly through a suitable arrangement or shape, or indirectly through the attachment of guide elements.

[0012] To minimize the connections of the hydrocyclone arrangement, the outlet lines should also be connected to the common light part outlet via a common discharge chamber.

[0013] For the replacement of existing, individual hydrocyclones, it is advantageous, due to the limited space available, if the hydrocyclone arrangement comprises three to eight, preferably four, hydrocyclone chambers and / or if these are arranged as compactly as possible next to each other.

[0014] Because the inlet is usually located at the top, the common inlet chamber should also be positioned above the hydrocyclone chambers. This, in turn, allows for a very simple and space-saving layout of the inlet channels. Advantageously, the inlet channels should run predominantly vertically for at least a first section after the inlet chamber and / or predominantly horizontally after that first section.

[0015] The fiber suspension is generally blown tangentially through the inlet into the hydrocyclone chamber, where centrifugal force presses the suspension against the chamber wall. The suspension then moves in a spiral motion from the inlet towards the heavy particle separator.

[0016] The hydrocyclone chamber should be conical, at least in sections, with the diameter decreasing towards the separator. This reduction in diameter increases the rotational speed and thus the centrifugal forces. As a result, the heavier particles are pressed against the wall of the hydrocyclone chamber and concentrated there. At the end of the hydrocyclone chamber, the heavier particles can then be discharged via the separator.

[0017] Since the light particles concentrate in the central axis of the hydrocyclone chamber, a preferably tubular light particle outlet, extending along the central axis, should project from the inlet end of the hydrocyclone chamber into the center of the chamber. The light particles can then be pumped out of the suspension via this outlet.

[0018] In order to be able to purify fibrous suspensions of high density, it is advantageous if, for example as described in EP 1 069 234, at least one supply line for dilution fluid leads into the hydrocyclone chamber.

[0019] Particular advantages arise when the hydrocyclone arrangement is used to clean the fiber suspension of heavy parts and the cleaned fiber suspension is discharged via the light part outlet.

[0020] However, it is also possible to remove light particles from the fiber suspension via the outlet and to discharge the cleaned fiber suspension via the separator.

[0021] Due to its high wear resistance, the hydrocyclone assembly is advantageously suited for purifying fibrous suspensions used in the production of paper, cardboard, tissue, or other fibrous webs, preferably with a density between 0.5 and 4%, and particularly between 1.5 and 3%. This is especially true when dilution fluid is supplied via a feed line.

[0022] The invention will now be explained in more detail using an exemplary embodiment. The accompanying drawing shows the Figures 1 and 2 various cross-sectional views of the hydrocyclone arrangement and Figure 3 a schematic longitudinal section through a hydrocyclone chamber 1.

[0023] The hydrocyclone arrangement consists of Figures 1 and 2consisting of four compactly arranged hydrocyclones for the purification of a fibrous suspension with a material density between 1.5 and 3% of heavy particles.

[0024] The stationary housing of the hydrocyclones encloses each elongated hydrocyclone chamber 1 with a circular cross-section, wherein the central axes 14 of the hydrocyclone chambers 1 of the hydrocyclone arrangement run parallel to each other.

[0025] As in Figure 3 As can be seen, an inlet 2 is located at one end of the hydrocyclone chamber 1, through which the fiber suspension to be cleaned is injected tangentially into a cylindrical inlet section of the hydrocyclone chamber 1. This causes the fiber suspension to move along a circular path, pressing it against the wall of the hydrocyclone chamber 1.

[0026] Due to the centrifugal and centrifugal forces acting during this process, the heavier particles accumulate on the wall of hydrocyclone chamber 1, while the lighter particles accumulate in the center of the hydrocyclone chamber 1. In this way, the heavy particles spiral along the wall of hydrocyclone chamber 1 to the opposite end of the hydrocyclone chamber 1, where the heavy particle separator 12 is located, and through which the heavy particles are discharged from the hydrocyclone.

[0027] To prevent blockages in the heavy particle separator 12, dilution fluid is fed into the hydrocyclone chamber 1 via a supply line 13 in the area of ​​the heavy particle separator 12. This allows the hydrocyclone to operate without problems even at high substance densities, as is the aim here.

[0028] The fiber suspension, purified of heavy particles and located in the center of hydrocyclone chamber 1, is pumped out here as the light particle component via the light particle outlet 3. For this purpose, a tubular light particle outlet 3 extends from the inlet end along the central axis 14 into the center of chamber 1.

[0029] The cylindrical inlet section is followed by, according to Figure 3 In the direction of the heavy particle separator 12, a conical hydrocyclone section is formed in which the diameter of the hydrocyclone chamber 1 decreases continuously towards the heavy particle separator 12. This narrowing increases the rotational speed of the suspension to such an extent that the heavy particles concentrate on the wall of the hydrocyclone chamber 1.

[0030] The light part outlet 3 extends into the cylindrical inlet section.

[0031] If light particles are to be removed from the fiber suspension, the fiber suspension cleaned of these particles is conveyed out of the hydrocyclone as the heavy particle component via the heavy particle separator 12, while the light particles are discharged via the light particle outlet 3.

[0032] At inlet 2 of the hydrocyclone chamber 1, the fiber suspension is injected at a pressure of up to 4 or even 6 bar, which leads to a high load.

[0033] Therefore, the hydrozyc clone assembly is formed from a mixed construction of metal and plastic.

[0034] Accordingly Figures 1 and 2 Above the four hydrocyclone chambers 1 of the hydrocyclone arrangement is a common inlet chamber 4, into which a common inlet 5 for the fiber suspension to be cleaned flows tangentially.

[0035] This inlet chamber 4 is connected to the corresponding inlet 2 of the hydrocyclones via a separate inlet channel 9.

[0036] The inlet channels 9 run vertically from the inlet chamber 4 via a first section 10 and horizontally in the following section 11.

[0037] In front of inlet 2, the inlet channel 9 is curved and, especially before the confluence, hugs the outer circumference of the corresponding hydrocyclone chamber 1.

[0038] Above the common inlet chamber 4 there is also a common outlet chamber 7, which is connected via separate outlet lines 6 to the corresponding light part outlets 3 of the hydrocyclone chambers 1.

[0039] The outlet pipes 6 are individually guided through the inlet chamber 4 and act as a guiding element to ensure a better distribution of the fiber suspension.

[0040] The tangential inflow of the fiber suspension leads to an annular flow in the inlet chamber 4, which, however, is disturbed by the outlet lines 6 and thus supports the supply to the inlet channels 9.

[0041] From the discharge chamber 7, the purified fiber suspension can be discharged from the hydrocyclone assembly via a common, off-center, upward-directed light particle outlet 8. This off-center arrangement is particularly advantageous when the hydrocyclone assembly is intended to replace a single hydrocyclone and utilize its existing connections.

[0042] This results in a simple and space-saving design for the hydrocyclone arrangement, so that it can replace existing hydrocyclones.

Claims

1. Hydrocyclone arrangement for the replacement of individual hydrocyclones for cleaning a pulp slurry, comprising several hydrocyclone chambers (1) of circular cross section, into each of which an inlet (2) and a lightweight particle outlet (3) open at one end and a heavy particle separator (12) opens at the opposite end, wherein the inlets (2) are connected to a common feed (5) via a common feed chamber (4), the lightweight particle outlets (3) are connected to a common lightweight particle discharge (8) via separate outlet lines (6) that pass through the common feed chamber (4), wherein the common feed chamber (4) is connected to the inlets (2) via separate inlet channels (9), characterized in that in each case the inlet channel (9) curves in front of the inlet (2) and closely follows the outer circumference of the hydrocyclone chamber (1).

2. Hydrocyclone arrangement according to Claim 1, characterized in that the outlet lines (6) are connected to the common lightweight particle discharge (8), arranged eccentrically in relation to the discharge chamber (7) and preferably directed upwards, via a common discharge chamber (7).

3. Hydrocyclone arrangement according to either of the preceding claims, characterized in that at least one component of the common feed (5) opens tangentially into the feed chamber (4).

4. Hydrocyclone arrangement according to one of the preceding claims, characterized in that at least one component of the common feed (5) opens tangentially into the feed chamber (4) with a circular cross section, wherein the circular cross section is intended to form an annular flow.

5. Hydrocyclone arrangement according to one of the preceding claims, characterized in that guiding elements are accommodated in the feed chamber (5), which guide the pulp slurry to the inlet channels (9).

6. Hydrocyclone arrangement according to one of the preceding claims, characterized in that three to eight, in particular four, hydrocyclone chambers (1) are positioned as compactly as possible one beside the other.

7. Hydrocyclone arrangement according to one of the preceding claims, characterized in that the common feed chamber (4) is arranged above the hydrocyclone chambers (1).

8. Hydrocyclone arrangement according to Claim 7, characterized in that the inlet channels (9), following on from the feed chamber (4), run at least predominantly vertically over a first section (11).

9. Hydrocyclone arrangement according to Claim 7 or 8, characterized in that the inlet channels (9), following on from the feed chamber (4), run at least predominantly horizontally after a first section (11).

10. Hydrocyclone arrangement according to one of the preceding claims, characterized in that at least one tangential component of the inlets (2) opens into the respective hydrocylone chamber (1).

11. Hydrocyclone arrangement according to one of the preceding claims, characterized in that the hydrocylcone chambers (1) are of at least partially conical design.

12. Hydrocyclone arrangement according to one of the preceding claims, characterized in that, at the inlet end of the respective hydrocyclone chamber (1), a preferably tube-shaped lightweight particle outlet (3) protrudes into the centre of the hydrocyclone chamber (1).

13. Hydrocyclone arrangement according to one of the preceding claims, characterized in that at least one supply line (13) for dilution fluid opens into each of the hydrocyclone chambers (1).

14. Hydrocyclone arrangement according to one of the preceding claims, characterized in that the cleaned pulp slurry is discharged via the lightweight particle outlet (3).

15. Hydrocyclone arrangement according to one of the preceding claims, characterized in that the pulp slurry used to produce a paper, cardboard, tissue or other web preferably has a consistency of between 0.5 and 4%, in particular between 1.5 and 3%.