BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a partial area of a known disc for disc-type centrifuges having a vertical axis of rotation.
FIGS. 2 to 8 are top views of a partial area of embodiments of different discs for disc-type separators or centrifuges having a vertical axis of rotation, according to the present disclosure.
FIG. 9 is a sectional view of a separator having two distributor channels, according to the present disclosure.
FIG. 10 is a top view of a distributor for the separator of FIG. 7.
DETAILED DESCRIPTION
FIG. 1 shows a top view of a partial area of a known disc 1 of a disc stack for a separator.
According to FIG. 1, the discs 1 each have a disc bore 2. The bores 2 or holes of the discs 1, in cooperation with several discs 1 arranged above one another, form a rising channel 3 which is situated radially in an area of a separating zone T between a lighter and a heavier liquid phase. In an area 4, a discharge of a light liquid phase takes place radially on an inside with respect to the discs 1, and a discharge of a heavier liquid phase takes place in an area 5 radially outside the disc 1. Solids exit a disc stack 26 toward an outside (not shown) and can be discharged there in a known manner, for example, through nozzles or a piston valve arrangement from a centrifugal drum.
The disc stack 26 or the individual discs 1 are pushed onto a distributor shaft 16 which includes, on its outer circumference, a plurality of webs 17 directed radially from the shaft 16 to an outside, which webs 17 protrude beyond an inner circumference I of the discs 1 and thereby non-rotatably secure the discs 1 on the distributor shaft 16 relative to the shaft 16.
As a radial extension of the webs 17, radially directed spacers or lugs 18 are arranged between the discs 1, which spacers 18 divide the discs 1 completely into segments 19 with an opening angle α, in which one bisecting line W is situated.
The area 4 for discharging the light phase is formed by grooves 20 in the outer circumference of the distributor shaft 16 between the webs 17, which grooves 20 are placed symmetrically with respect to the bisecting lines W in the distributor shaft 16.
According to FIG. 2, the rising channel 3 has a cross-section which is not constant. That is, a diameter of the bores 2 of the discs 1 of the disc stack 26, which form the rising channel 3, is not constant. The diameter changes over an entire height of the disc stack 26 and it is reduced continuously along the entire height of the disc stack 26 in a flow direction F (see FIG. 9).
It is noted that it is known from British Patent Document GB 264,777 to provide the lowermost disc with a different hole or bore arrangement than the upper discs in order to cover a portion of the discs and be able to thereby radially displace the rising channel by exchanging the lowermost disc.
The diameter of the bore 2, as shown in FIG. 2, for a drum with a vertical axis of rotation, continuously decreases in an upward direction (indicated by a broken line), so that the diameter of the rising channel 3 is also reduced in the upward direction.
In addition, the rising channel 3, as shown in FIG. 2, is not situated parallel to a drum axis M which is perpendicular to a plane of the figure. As a result, the bores 2 of discs 1 situated above one another are no longer aligned completely but only in sections, so that the rising channel 3 may, for example, extend in the upward direction radially from the outside farther toward the inside and/or in or against a rotating direction in a circumferential direction and may therefore have a twist.
According to FIG. 2, the groove 20 in the distributor shaft 16 for forming a discharge channel or discharge area 4 is not symmetrically aligned with respect to the bisecting line W of each disc segment 19 but is asymmetrically laterally offset. This can also optimize the flow conditions in the disc stack 26.
According to FIGS. 3 to 5, discharge channels 6, 7 are constructed directly in the disc stack 26. That is, a first discharge channel 6 for a light liquid phase is constructed radially outside the inner circumference I of the discs 1 in the disc stack 26, and a second discharge channel 7 for a heavier liquid phase is constructed radially inside the outer circumference A of the discs 1. These channels 6, 7 also may be aligned not only symmetrically but also asymmetrically with respect to the bisecting line W of each disc segment 19. This also applies to the rising channels 3 for the product feed.
The discharge channels 6, 7 are formed analogously to the rising channels 3 by bores 8, 9 in the discs 1 situated above one another, which bores 8, 9 are situated close to the inner I or outer A circumference of the discs 1. The discharge channels 6, 7 may again have a diameter which is not constant and/or may not be situated directly above one another but offset with respect to one another relative to a drum axis M. To this extent, all of the arrangements of the bores 2 for the rising channels 3 mentioned above or below can be analogously utilized also when further developing the bores 8, 9 for the discharge channels 6, 7.
According to FIG. 3, the bores 8 of the inner discharge channel 6 for the light liquid phase and/or the bores 9 of the discharge channel 7 for the heavier phase and/or the bores 2 of the rising channel 3 may include several bores 2, 8, 9 in a manner of a multiple perforation 10. In this case, individual bores can be arranged, for example, in a circle 12, in a radially oriented straight line or in a curve oriented in the circumferential direction or a straight line 13. The curves or straight lines may be arbitrarily oriented in an angular and/or offset manner with respect to the bisecting line W of the segment 19 or to other radial lines through the drum axis M of the centrifuge depending on the application.
According to the present disclosure, a division of the product flow into many small channels represents an improvement with respect to the uniform charging of the disc stack 26s and optimizes the flow conditions in the disc stack 26.
The individual bores 2, 8, 9 may have any geometry. Thus, a circular shape or a polygonal shape, for example, a triangular or square shape, as shown in FIG. 4 or a curved shape, as shown in FIG. 5. The polygon or the other geometrical shapes can be oriented at any angle with respect to the bisecting line W of the angle.
It is advantageous to mutually adapt the geometry of the bores 2, 8, 9 of a rising channel 3 such that gaps between the discs 1 are uniformly charged with liquid over the entire height of the disc stack 26 or the rising channel 3. This can be achieved by tests and/or theoretical considerations, such as computer simulations.
FIGS. 6 to 8 illustrate that, by an optimized development of the distributor, it becomes possible to further optimize the flow conditions in the drum 21 (see FIG. 9) as well as in the disc stack 26.
A one-piece distributor 22 (see FIG. 10) is provided with distributor channels 14 which are not radially oriented. The channels 14 are constructed as a bore (see FIG. 9) and, first extend in a first bore section in the drum 21 in a sloped manner from an inside to an outside in a downward direction and end in a bore section which is constructed as an expanding or geometrically changing distributor outlet 15a. This distributor outlet 15a is directed upward in the drum 21 and leads directly below one of the rising channels 3. Its outlet area may have a circular or, for example, slot-type shape. Slot-type distributor outlets 15b (see FIG. 7) from the bores of the distributor channels 14 may then, in turn, extend relative to a remaining distributor channel tangentially to radial line R in the rotating direction r of drum 22 (FIG. 7) or against (FIG. 8) the rotating direction r of the drum 22, or may advance or lag.
It thus becomes possible to optimize the flowing of product into the drum 22 as well as into the disc stack 26 in a very targeted manner while a feeding bore cross-section is optimized. This is in order to achieve an improved separation of particles and, if required, improve a parallel connection of the discs 1.
FIG. 9 is a cross-sectional view of a schematically illustrated self-discharging separator having a drum 21 with a vertical axis of rotation D, which has a distributor 22. A feeding pipe, which is not shown, leads from above into the distributor 22. The distributor 22 has the upper distributor shaft 16, which is oriented concentrically with respect to the axis of rotation D. The distributor 22 includes distributor channels 14 which are constructed as bores and each lead into one of the distributor outlets 15 (as shown in FIG. 9) or 15a,b,c (as shown in FIG. 10). A piston valve 23 is used for the opening and closing of solids discharge openings 24. The liquid discharge from the drum 24 takes place by grippers or centripetal pumps (not shown).
FIG. 10 is a top view of the distributor 22 with the distributor shaft 16 and the lower, radially expanding, almost disc-type base section 25. Section 25 is penetrated by, for example, three distributor channels 14, shown here by broken lines, and leading into the distributor outlets 15a,b,c.
Straight bores, which form the distributor channels 14 in the one-piece distributor 22, are not arranged radially but relative to the radial line R through the drum axis M (congruent with the axis of rotation D) in a lagging manner with respect to the rotating direction r, which permits a careful inflow of the centrifugal material.
The holes of the rising channel 14 are designed not to be constant over the height of the disc stack 26. The holes are designed in an optimized manner with respect to the flow conditions to not be constant, that is, to be variable. An angle β between the distributor channels 14 and the radial line R, which extends through a starting area of the distributor channel 14 at an inner circumference of the distributor 22, amounts to between 15 and 85°, particularly between 25° and 65°, in order to achieve a careful inflow of the centrifugal material into the drum 21.
The distributor outlets 15a,b,c may have various geometries which are also adapted to the rising channels 3 and which may be oriented to be lagging 15b, advancing 15c or “neutral” 15a relative to a lagging distributor arm (see also FIG. 10).
Although the present disclosure has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. The scope of the present disclosure is to be limited only by the terms of the appended claims.
Patent Application
20080015099
