Disc separator for centrifugal processing of a suspension

Abstract

The invention relates to a self-emptying disc separator for clarifying and / or separating a flowable suspension into one or more liquid phases and at least one solid or sludge phase, wherein a movable piston slide (17) is arranged in the centrifugal drum (1), by means of which piston slide solid discharge openings (16) can be opened and closed, wherein the piston slide (17) tapers, in a radially outer conical region (171) on its side situated towards the separating chamber (2), conically axially from top to bottom and radially inwardly, wherein the outer conical region (171) has a piston slide slope angle α on the inner cone surface (1711) thereof relative to a parallel to the axis of rotation, and wherein a disc stack (12) composed of a stack of conical separating discs (13) is arranged in the centrifugal drum (2), which disc stack projects at least in sections axially from above into the piston slide (17). It is then further provided that the piston slide slope angle α is less than 15°, in particular less than 14°, at least in a section of the outer conical region (171) closest to the disc stack (12).

Description

[0001] Disc separator for centrifugal processing of a suspension

[0002] The invention relates to a disc separator for the centrifugal clarification and / or separation of a suspension into several product phases, which comprise at least one or more liquid phases and at least one solid phase, with a centrifugal drum in which a disc stack of separation discs is arranged, according to the preamble of claim 1.

[0003] During the centrifugal processing of a flowable suspension with a disc separator, this suspension is separated in the rotating centrifugal drum with the aid of a disc stack or a disc stack of separating discs into several product phases, which may comprise at least one liquid phase or several liquid phases and preferably at least one solid phase. In the context of this document, a solid phase is also understood to mean a sludge phase, i.e., a mixture of solids and a small amount of liquid, both with regard to the prior art and with regard to the invention.

[0004] The solids are discharged either discontinuously, semi-continuously (self-emptying or self-cleaning centrifuges, which automatically empty the solids accumulated in the sludge chamber at periodic intervals using a piston valve mechanism) or completely continuously (nozzle separator).

[0005] The centrifugal drum can have an upper drum section and a lower drum section. One or both of these drum sections can be conical on the inside. It is also known to design the piston slide provided in self-emptying disc separators with a conical interior in some sections.

[0006] For conventional disc separators, there is a need for new design concepts to achieve excellent separation performance in the simplest possible way. The separation performance of a disc separator depends on various factors, including the number and surface area of ​​the separation discs arranged in the centrifugal drum.

[0007] In order to accommodate the largest possible separation disc surface in a small space, attempts have already been made to optimize the cone angles—also called the slope angles—of the drum base, drum top, and / or piston valve. For example, DE102008048934A1 proposes dimensioning the slope angle of the piston valve at 15° (to the rotational or rotary axis).

[0008] This was taken up again in EP4046719A1, which proposes combining a slope angle of the piston valve equal to or greater than 15° with a slope angle of the drum upper section less than 15°, and selecting the disc angles between 30° and 50° (all angles to the rotation axis). This is advantageous for accommodating a relatively large number of separating discs in the separating chamber.

[0009] DE102006027893A1 proposes selecting a slope angle of the lower drum section between 15 and 60° and a slope angle of the upper drum section between 30 and 60°. This slope angle refers to the rotation axis of the disc separator.

[0010] In DD156219 it is disclosed that the slope angles a of the piston valve or the upper part of the drum in the area of ​​the sludge chamber do not necessarily have to have a constant value, but can also increase radially outwards.

[0011] Despite these proposals, there is still a need for improved centrifugal separators that combine very high separation performance with a compact design in a structurally simple manner.

[0012] The solution to this problem is the object of the invention.

[0013] The invention solves this problem by the subject matter of claim 1. A self-emptying disc separator is provided for clarifying and / or separating a flowable suspension into one or more liquid phases and at least one solid or sludge phase, comprising a centrifugal drum having a centrifugal drum upper part and a centrifugal drum lower part forming a separation chamber, wherein the centrifugal drum comprises an inlet for the suspension, at least one liquid phase outlet and at least one solid discharge having a plurality of solid discharge openings distributed circumferentially in the centrifugal drum, wherein a movable piston slide is arranged in the centrifugal drum, with which the solid discharge openings can be opened and closed,wherein the piston slide tapers conically axially from top to bottom and radially inward in a radially outer conical region, at least on its side facing the separation chamber, wherein the outer conical region has a piston slide slope angle α on its inner conical surface relative to a line parallel to the axis of rotation, and wherein a disc pack consisting of a stack of conical separating discs is arranged in the centrifugal drum, which protrudes at least partially axially from above into the piston slide. It is provided that the piston slide slope angle α is less than 15°, in particular less than 14°, at least in a section of the outer conical region closest to the disc pack.

[0014] This is extremely advantageous, as it allows a particularly large clarification area to be achieved in a compact space. For disc separators with an internal piston valve, with a piston valve slope angle α of less than 15°, in particular less than 14°, the diameter D3 usable for the separation disc can be advantageously increased in relation to the maximum inner radius of the piston valve D2 in the separation chamber or towards the separation chamber, namely up to 92%, i.e., D3 / D2 <= 0.92. If the piston valve slope angle α is less than 14°, these advantageous effects are significantly enhanced.

[0015] In this document, a conical region of a component of the disc separator is understood to be a region that either has a cone angle that is constant within this region or a cone angle that changes within this region, for example, increasing or decreasing.

[0016] The invention is particularly advantageous for disc separators in which the conical region extends between a base region of the piston slide, in particular a horizontally or substantially horizontally oriented base region, and a - preferably horizontally oriented - contact surface of the piston slide, which, when the solids discharge openings are closed, rests against the upper part of the drum, so that the solids discharge openings are closed. It has been recognized that the slope angle α of the internal piston slide has a particularly significant influence on the maximum foreseeable diameter of the base region and thus on the maximum possible diameter D3 of the discs to be used.If we now assume the maximum diameter D2 of the inner contour of the drum to be given and thus constant, a smaller angle of repose a of the outer conical area of ​​the piston valve can increase the diameter D1 of a base area in particular and thus increase the space available for the plates. This means that the same number of plates but with a larger diameter can be placed in the separation chamber. The piston valve base can be aligned exactly horizontally, but it can also be slightly inclined to the horizontal (e.g. inclined by less than 30°) or have a different geometry, as long as the lowest separation plate is well received in the piston valve. The separation plates themselves are conical and widen from top to bottom as well as with increasing radius and can be arranged on a distributor.The contact surface to the upper part of the drum, which is not open to the separation chamber when the solids discharge openings are closed, is not taken into account when determining the diameter D2.

[0017] It can be provided that the piston valve slope angle α is less than 15°, in particular less than 14°, in the entire outer conical region. However, it can also be provided that the piston valve slope angle α is not less than 15°, in particular less than 14°, in the entire outer conical region, as long as the installation of the disk pack is possible without problems. The piston valve slope angle α can be constant or not constant in the outer conical region. For example, it can be provided that the piston valve slope angle α increases radially from the inside to the outside in the outer conical region. However, it can also be the case that the piston valve slope angle α decreases radially from the inside to the outside in the outer conical region. Inwardly or outwardly curved slopes or inner conical surfaces in the outer conical region are also conceivable.With the help of the above variants, in particular the volume of the sludge or solids collection chamber outside the plate pack in the separation chamber can be suitably selected.

[0018] The invention is particularly advantageously suitable for disc separators in which the outer conical region of the piston slide, together with an inner cone of the drum upper part, essentially delimits the separation space in its radially outer region in a double-conical manner.

[0019] Further advantageous embodiments can be found in the remaining subclaims.

[0020] The invention is described in more detail below using exemplary embodiments with reference to the figures. Figure 1 shows a section through a centrifugal drum of a first disc separator according to the invention;

[0021] Fig. 2 shows a section through a centrifugal drum of a second disc separator according to the invention; and

[0022] Fig. 3 shows a section through a centrifugal drum of a third disc separator according to the invention.

[0023] Fig. 1 shows a section through the area of ​​a centrifugal drum 1 of a disc separator, with which a liquid product—a suspension—can be clarified into various product phases comprising at least one liquid phase and one solid phase. Not shown are additional components such as a drive and control system, as well as a hood and frame of the disc separator.

[0024] The centrifugal drum 1 has a separation chamber 2. It also has a vertical axis of rotation D. It is mounted on a driving spindle 3, which is rotatable by a drive (not shown here). An inlet pipe 4 is guided from above into the centrifugal drum 1. Other designs, for example, with a product feed line through the lower spindle 3 or with a suspended centrifugal drum (not shown here), are also conceivable in principle.

[0025] The centrifugal drum 1 comprises a drum base 5 and a drum top 6, one or both of which can be conical, particularly on the inside—and optionally one or both of which can also be conical on the outside. Thus, the drum top 6 has an inner cone 61. The drum top 6 is screwed to the drum base 5 with a locking ring 62. The inlet pipe 4 passes through a drum cover 7, which can be connected to the drum top 6 in a rotationally fixed manner. The inlet pipe 4 can be designed to be stationary or co-rotating during operation.

[0026] The inlet pipe opens into a distributor 8 with a distributor shaft 9 and a distributor base 10. Suspension emerging from the inlet pipe 4 can be guided through the distributor 8 through distributor channels 11 (here, for example, through an annular gap "x" between the outer diameter of the distributor base 10 and the inner surface of a piston valve 17 (to be explained later)) into the separation chamber 2, whereby the suspension in the distributor base 10 is accelerated in the distribution channels 11 in the circumferential direction to the speed of the centrifugal drum. This design of the distributor 8 is advantageous because the suspension to be accelerated to circumferential speed is subjected to only low shear forces. However, the distributor can also be designed differently.

[0027] In the separation chamber 2, the actual separation of the supplied suspension into various product phases then takes place in a continuous process. These phases comprise at least one liquid phase F1 and at least one solid or sludge phase (otherwise referred to synonymously as the "solid phase"). However, several liquid phases can also be separated from one another using a suitably modified centrifuge drum (known to those skilled in the art, not shown here).

[0028] To achieve a large clarification surface and thus a high separation efficiency, a disc pack 12 is arranged in the centrifugal drum, which comprises a stack of separation discs 13. This disc pack 12 can be placed on the distributor 8 so that the distributor shaft 9 passes through it centrally, with the lowest of the separation discs 13 resting on the top side of the distributor base 10.

[0029] The separating plates of the plate pack 12 are conical and have an inner circumference and preferably a constant outer circumference with a diameter D3. They expand radially from top to bottom.

[0030] The at least one liquid phase is discharged from the separation chamber 2 through at least one liquid outlet. This comprises, for example, a paring disc 14 arranged in a paring chamber 15 above the disc stack 12.

[0031] The at least one solid phase, however, is guided out of the drum through circumferentially distributed solid discharge openings 16, which can be opened and closed again as needed or at intervals by a piston valve 17 (or the one already mentioned) arranged in the centrifugal drum 1.

[0032] For this purpose, the piston slide 17 is preferably arranged to be movable axially within the centrifuge drum 1. To move it, an actuator device is assigned to the piston slide 17, which can, for example, comprise a fluid control chamber 18 that can be pressurized with fluid (along with a supply and discharge system (not shown here) for a fluid to be filled into and drained from the control chamber) and optionally one or more springs (only the fluid chamber is shown here; the function of actuating the piston slide 17 is known to those skilled in the art; see, for example, DE 2208490 C).

[0033] It is important that no unnecessary shear forces occur during distribution of the mixture, which could break up the fine particles of the suspension or create emulsions. In clarification separators, the product to be separated is fed radially from the outside into the disc pack. In separation separators, there are often additional rising channels in the disc pack 12 (not shown here). Separation takes place within the disc pack of the disc separator 3. The solids are forced outwards and collect in the so-called solids chamber 19. The separated liquid phases flow through the disc pack into the upper part of the centrifugal drum, where they flow off via a paring disc (grabber) 14 or a fixed weir. The configuration used depends on the application.

[0034] The piston slide 17 is preferably inserted into the drum lower part 5 and is guided axially displaceably therein on its outer circumference 174 and here also on its inner circumference 178 in the region of an inner shoulder 51 of the drum lower part 5.

[0035] What is important here is that the piston slide 17 tapers conically radially inwards and axially from top to bottom in a radially outer region 171 on its side facing the separation chamber 2 (hereinafter referred to as “outer conical region 171”).

[0036] The following features describe the piston slide 17 of Fig. 1 in more detail, but do not necessarily have to be implemented in their entirety within the scope of the invention, but can also be implemented only in part.

[0037] In its closed position, the piston valve 17 rests upwards in a radially outer annular region 172 with a preferably horizontally oriented contact surface 173 on the upper drum section 6 and is guided radially outwardly in the lower drum section 5 by a cylindrical peripheral surface 174, into which a sealing ring 175 can be inserted. This annular region 172 is then adjoined by the conical region 171 with an inner conical surface 1711 (and here also with an outer conical surface 1712). The conical region 171 of the piston valve 17, together with an inner cone 61 of the upper drum section 6, essentially delimits the separation chamber 2 in the outer region in a double-conical manner. Further radially inward, a flat, horizontally oriented annular section 176 - referred to as the base region - can adjoin the conical region 171.

[0038] The piston slide 17 can then optionally have a further conical region 177 radially further inward, as shown here, in which the piston slide tapers axially upwards again with decreasing diameter. On its inner circumference 178, it can in turn be guided on the corresponding inner shoulder 51 of the drum base 5, into which the spindle 3 can preferably also engage from below. A further seal 179 can be arranged between the inner circumference 178 and the inner shoulder 51.

[0039] The disc pack 12 has an outer diameter D3. This is preferably constant, since all separating discs have this outer diameter D3. Theoretically, however, it is also conceivable that some of the separating discs 13 have a slightly larger diameter than others. The conical region 171 of the piston slide has a largest inner circumference D2 (here it transitions into the contact surface 173). The separating chamber 1 also has a largest inner diameter. This can correspond to the largest inner diameter D2 of the conical region 171 of the piston slide 17. The conical region 171 of the piston slide also has a smallest inner circumference D1 (here it transitions into the flat base region 176).

[0040] During operation, when the centrifugal drum 1 rotates, the separated solid phase collects in a solid collection chamber 19 between the outer circumference D2 of the plate pack 12 and the area of ​​the largest inner diameter D3 of the separation chamber, virtually in front of the piston slide 17 and thus also the solid discharge openings 16. If the piston slide 17 is now moved axially downwards, the solid discharge openings open and the solid discharge starts (not shown here).

[0041] The centrifugal drum 1 is designed for quasi-continuous operation, in which the suspension is fed in continuously and the liquid phase is discharged continuously and the solid or sludge phase is discharged discontinuously - as described above. The control and / or regulation of the solids discharge is carried out by a control device not shown here. The solids discharge is started, for example, whenever the solids collection chamber is full. Since the inner conical surfaces of both the drum upper section 6 and the piston slide 17 are provided with a slope angle ß, α, this essentially results in a double-conical inner contour in this area of ​​the separation chamber 2. This allows the separated solids to slide to the discharge openings or solids discharge openings 16.

[0042] In order to be able to arrange a disk pack 12 with a very large clarifying surface in the separation chamber, the conicity angle or slope angle a of the conical region 171 is designed to be less than or equal to 15°, in particular less than 14°, so that the piston valve 17 is relatively "steep" in this region. The conicity angle a is measured relative to the vertical axis of rotation A or a straight line parallel to the axis of rotation A.

[0043] The slope angle ß of the inner cone 61 of the drum upper section 6, however, can be chosen arbitrarily. For example, it can correspond to the conicity angle of the separating discs 13 or be larger or smaller than it.

[0044] It was recognized that it is less the angle of repose ß of the inner cone 61 of the upper drum section 6 than the angle of repose α of the inner cone surface 1711 of the conical region 171 of the piston slide 17 that is of particular importance with regard to the question of whether a particularly large clarification surface can be achieved in a small space in a separation chamber 2 of a centrifugal drum 1 of a disc separator. This is because disc separators are always required to use separation discs with the largest possible diameter in a given drum interior space and thus to achieve a large disc surface or clarification surface. With this larger clarification surface, a larger amount of product can be separated or clarified, or the same amount of product can be separated or clarified better, i.e. with greater separation efficiency.

[0045] The angle of repose a of the internal piston slide 17 influences the maximum diameter D1 of the base area 176 and thus the maximum possible diameter D3 of the separation plates 13 to be used. If the maximum internal diameter D2 of the centrifugal drum 1 is assumed to be given and thus constant, the diameter D1 of the base area 176 can be increased or made very large by using a smaller angle of repose a of the piston slide 17, and thus the space available for the separation plates 13 can be increased. This means that the same number of separation plates 13 with a particularly large or larger diameter can be placed in the separation chamber 2. However, this reduces the available sludge space or solids collection space 19. For certain products, which, for example, tend to stick or have a very high solids content, small angles of repose may be less suitable.However, this disc separator does not have to be used there. For products with a low sludge content and good sliding properties, it is very advantageous to design the piston slide and, if applicable, also the upper part of the drum with smaller slope angles. The disc separators according to the invention can be used particularly advantageously here. In disc separators with an internal piston slide 17, with a slope angle of the piston slide 17 of less than 15°, in particular less than 14°, the diameter D3 usable for the separating discs can then be advantageously increased in relation to the maximum inner radius of the piston slide D2, namely up to 92%, i.e. D3 / D2 <= 0.92.

[0046] In order to achieve this positive effect, the slope angle a of the piston slide 17 does not necessarily have to be constant in its axial course, although such a design is very advantageous.

[0047] Rather, inwardly or outwardly curved inner conical surfaces 1711 or slopes (Fig. 2, Fig. 3) with non-constant slope angles a can also be realized, or even chamfered slopes, as shown, for example, in DE102006027893A1 or DD156219. In Fig. 2, the conical section 171 is thus slightly convex toward the inside, and in Fig. 3, it is slightly concave.

[0048] However, according to the invention there is then also at least one inner section on the inner surface 1711 of the conical region 171, which is closest to the plate stack, in which the slope angle a (or “a1” in Figs. 2 and 3) is less than 15°, in particular less than 14° (there the gap width “x” is designated in Figs. 1, 2 and 3).

[0049] Outside this point or section (in Fig. 2 radially further outwards), the slope angle (then designated as a2) (convex slope or inner conical surface 1711 ) can then again be 14° or 15° or more than 14° or 15° (see Fig. 2).

[0050] In Fig. 3, in the inner section closest to the disk stack (where the gap width "x" is designated in Fig. 3), the slope angle a1 on the inner surface 1711 of the conical region 171 is less than 15°, in particular less than 14°. Outside of this point or this section (radially further outward in Fig. 3), the slope angle a2 (concave slope or inner conical surface 1711) can then become even smaller.

[0051] If, in contrast to the previously described embodiment, the disc pack 12 is not enlarged in its diameter D3 with a constant drum inner diameter D2 and a reduced slope angle a, but has an equal or smaller diameter D3', a larger sludge or solids collection chamber 19 is created, which in turn can be advantageous for suspensions to be separated with an increased solids content.

[0052] The conicity or slope angle ß of the centrifugal drum upper part 6 can be constant or can be greater in an upper region of the centrifugal drum upper part than in a lower region of the centrifugal drum upper part (Fig. 1, Fig. 2, Fig. 3), in particular in the region in which it delimits the solids collection chamber 19 from above. In the upper part, the slope angle ß of the centrifugal drum upper part preferably corresponds to the slope angle of the separation plates 13. In the region of the solids collection chamber 19, it can, for example, be smaller than the plate angle ßTeiier, preferably smaller than 20°.

[0053] The separating plates 13 preferably have a slope angle ßT = ßTeiier of 25° to 50° relative to the rotation axis. Since the calculated equivalent clarification area is proportional to tan (90° - ßTeiier), it may even be advantageous in some cases to choose an angle ßT = ßTeiier smaller than 25°.

[0054] Reference symbol

[0055] Centrifugal drum 1

[0056] Separation room 2

[0057] Spindle 3

[0058] Inlet pipe 4

[0059] Drum base 5

[0060] Approach 51

[0061] Drum top 6

[0062] inner cone 61

[0063] Locking ring 62

[0064] Drum cover 7

[0065] Distributor 8

[0066] Distribution shaft 9

[0067] Distributor foot 10

[0068] Distribution channels 11

[0069] Plate package 12

[0070] Separator plate 13

[0071] Peeling disc 14

[0072] Peeling chamber 15

[0073] Solids discharge openings 16

[0074] Piston valve 17

[0075] Conical area 171

[0076] Inner conical surface 1711

[0077] Outer conical surface 1712

[0078] Ring area 172

[0079] Investment area 173

[0080] Circumferential area 174

[0081] Sealing ring 175

[0082] Bottom area 176 conical area 177

[0083] Inner circumference 178

[0084] Sealing ring 179

[0085] Fluid control chamber 18

[0086] Solids collection or sludge room 19

[0087] Slope angle a, ß

[0088] Diameter D1, D2, D3

[0089] Gap width x

Claims

Claims 1 . Self-emptying disc separator for clarifying and / or separating a flowable suspension into one or more liquid phases and at least one solid or sludge phase, a. with a centrifugal drum (1 ) which has a centrifugal drum upper part (6) and a centrifugal drum lower part (5) which form a separation chamber (2), b. wherein the centrifugal drum (1 ) comprises an inlet for the suspension, at least one liquid phase outlet (14) and at least one solids discharge which has a plurality of solids discharge openings (16) distributed around the circumference of the centrifugal drum, c. wherein a movable piston slide (17) is arranged in the centrifugal drum (1 ), with which the solids discharge openings (16) can be opened and closed, d.wherein the piston slide (17) tapers conically axially from top to bottom and radially inwards in a radially outer conical region (171) on its side facing the separation chamber (2), wherein the outer conical region (171) has a piston slide slope angle α on its inner conical surface (1711) relative to a line parallel to the axis of rotation, e. wherein a plate pack (12) made up of a stack of conical separating plates (13) is arranged in the centrifugal drum (2), which plate pack projects axially from above into the piston slide (17) at least in sections, characterized in that f. the piston slide slope angle α is less than 15° at least in a section of the outer conical region (171) closest to the plate pack (12).

2. Disc separator according to claim 1, characterized in that the piston slide slope angle a is less than 14° at least in a section of the outer conical region (171) closest to the disc pack (12).

3. Disc separator according to claim 1 or 2, characterized in that the diameter D3 usable for the separating discs in relation to the maximum in- The inner radius of the piston slide D2 in the separation chamber (2) satisfies the following relationship: D3 / D2 <= 0.

92.

4. Disc separator according to claim 1, 2 or 3, characterized in that the outer conical region (171) extends between a bottom region (176) of the piston slide (17), in particular a horizontally or substantially horizontally aligned bottom region (176), and a contact surface (173) of the piston slide (17), which in the closed state rests against the upper part of the drum (5), so that the solids discharge openings (16) are closed.

5. Disc separator according to claim 1, 2, 3 or 4, characterized in that the separating discs (13) of the disc pack (12) are conical in shape, widening from top to bottom and with increasing radius, and that they are arranged on a distributor (9).

6. Disc separator according to one of the preceding claims, characterized in that the piston slide slope angle a is not less than 15° in the entire outer conical region (171), in particular not less than 14° in the entire outer conical region (171).

7. Disc separator according to one of the preceding claims, characterized in that the piston slide slope angle a in the entire outer conical region (171) is less than 15°, in particular in the entire outer conical region (171) is less than 14°.

8. Disc separator according to one of the preceding claims, characterized in that the piston slide slope angle a is constant in the entire outer conical region (173).

9. Disc separator according to one of the preceding claims, characterized in that the piston slide slope angle a increases radially from the inside to the outside in the outer conical region.

10. Disc separator according to one of the preceding claims, characterized in that the piston slide slope angle a decreases radially from the inside to the outside in the outer conical region.

11. Disc separator according to one of the preceding claims, characterized in that the outer conical region (171) of the piston slide (17) together with an inner cone (61) of the drum upper part (6) delimits the separation space (2) in its radially outer region essentially in a double-conical manner.

12. Disc separator according to one of the preceding claims, characterized in that the slope angle ß of the centrifugal drum upper part (6) is greater in an upper region of the centrifugal drum upper part (6) than in a lower region of the centrifugal drum upper part (6), in particular in the Area in which it limits the solids collection chamber (19) from above.

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