DE19964175A1 - Plant separating mixture suspended in fluid on density basis, includes baffles directing central inlet flow uniformly to the sides, with plant controls optimizing settlement conditions for increased flow rate and separation efficiency - Google Patents

Abstract

A device controls the lower exit line (12) extraction flow rate. The flow contains heavier fractions. Preferred features: The unit controlling extraction is e.g. a pump. This operates with volumetric flow rate variation, rather than by altering the cross section for flow. The line is a flexible hose which can be raised and lowered to control output, without varying cross section. Baffles (4, 5) with horizontal arrangement, include a conical section (6, 7), directing flow out to the sides. At the top of the tank (1) there is an overflow with upper outlet line. Cross section of the overflow can be varied. Flow rates into the tank and out at the base, are monitored. Bottom extraction is controlled in terms of the influx. Pressure pulses, especially compressed air pulses are introduced into the bottom line. A line transferring the mixture made in the stirrer tank, comes from its side, into the separation tank. Level in the stirrer is maintained under control; it is operated at constant speed. Between the baffles, there are several vertical flow-calming baffles.

Description

The amount of waste of all kinds is increasing due to the increase in the population. Processing in landfills requires a large amount of space. A location near localities causes nuisance from ammonia vapors and threatens the health of the residents through spreading fungi and spores. Waste incineration to remove waste creates CO ₂ as waste gas, and slags are created that have to be landfilled. If waste materials made of plastics are burned, gases that have a toxic effect can be formed in addition to CO ₂ , which pollute the atmosphere. If such waste materials are sorted out and deposited, the sorted out volumes create an environmental impact, or they are unstable and are slowly biodegraded. This applies in particular to packaging material made of plastics with adhering food residues.

In the prior art, numerous attempts have been made To separate plastic-material mixtures for the purpose of recycling nen.

DE 28 27 335 A1, for example, is a funnel-shaped Separating device with a central agitator for separating known up to 200 ° C heated plastic particles. Per Problems with this device seem to lie in the fact that a turbulent flow against settling plates in the middle part of the funnel is generated and that heating of the fuel leads to changes in the densities of the plastics. In particular in the case of multilayer plastic objects, the achievable one is Degree of separation hardly sufficient.

DD 256 049 A3 describes a process for the preparation of "Plastic waste" known. This procedure also uses a funnel-shaped separator used in the upper Scope of the task of the material to be separated baffles having. The degree of purity is also in this device of the separated fractions hardly sufficient.  

FR 25 73 340 describes a process for the preparation of Plastic material after separation from paper with an intensive stirrer known. There are supposed to be plastic particles in a cylin deric tube with a constriction below the discharge pipes by creating a zone with a reduced flow dizziness in a light, floating and in a heavy, sinking fraction can be separated. With another Their constructive training should be in, with the broad upper egg separating hoppers. This is to be achieved in that the separation space is parallel has vertical partitions, the tubular partitions represent. On the circular dividing line of the two trich A small volume of a calming zone should exist form. This zone is in the horizontal direction from the flows in and out of the separation medium. This device device only allows the separation of plastics due to their chemical composition larger density differences exhibit. The varietal purity that can be achieved is hardly sufficient. The throughput capacity is also low in this device.

The publication Kunststoffe, 74/1984, page 189, right Column, line 9-13 from the bottom confirms that such Separation systems in the swimming and sinking process according to the state of the Technology in practical continuous use has proven to be too susceptible to faults have.

DE 42 09 277 A1 discloses a separation unit with an eccentric stirrer arranged in a cylindrical tube knows. Through an end plate with channel-shaped, to the pipe vertically directed outlet openings is said to be a sudden Reduction of the flow rate can be effected. But also working with this in the swimming and sinking process Device is a sufficiently pure separation with sufficient throughput can hardly be achieved.

From Ullmann's Encyclopedia of Technology, 4th edition, volume 2, Process Engineering I, 1972, page 77 is an upstream classifier known, which with a movable gooseneck for change the bed height is equipped. The classifier is like that trained that the free inlet overturned Funnel flows out and when it flows out over these ge  closed containers the flow direction up and down changes below. The classifier is used to separate sludge from kaolin. It is said to be a fine fraction of a coarse fractions are separated, but no fractions are distinguished density. Only the bed height, but not the discharge amount is controlled by the gooseneck.

From EP 0 557 816 A2, according to which the preambles of the independent patent claims were formed, a plant for separating mixtures of substances of different densities by means of a liquid separation medium by rising light and falling heavy fractions is known, which comprises the following:
A stirred tank for producing a mixture of the mixture of substances and the separation medium; at least one separation container; a in the central region of the separating container arranged separating unit through which the mixture is introduced into the separating container, the separating unit being constructed from two opposing cones, namely an upper and a lower cone, the mixture entering centrally through one of the cones; Outlet lines at the top and bottom of the separation tank; and at least one device for freeing the fractions thus separated from the separation medium. On a technical scale, this proposal did not come out of an experimental stage. It has been shown in practice that it is not possible to achieve adequate material separation with an acceptable throughput.

The invention has for its object systems and procedural to separate mixtures of substances of different densities Provide improvements with little effort in terms of variety and throughput.

This task is solved by a system according to the Oberbe handle of claim 1, which by a device for selective control of the pro through the lower outlet line Unit of time taken amount of the mixture of heavy fractions and separation medium is marked. Under "selective tax "is understood here as one which the below withdrawn quantity directly influenced, so a tax first change in the ratio from top to bottom cause a lot.  

There is none in the system disclosed in EP 0 557 816 such selective control is provided. Although it should there is a change in those introduced into the separation container Quantity also affect the quantity withdrawn below, a selective control according to the invention, which is a change the ratio of this quantity to the quantity imported - and thus also to the amount withdrawn above - is allowed there however not provided. Such selective control has an advantageous effect on the process control and therefore allows an increase in variety purity at high Throughputs.

It should be noted that the lower outlet line is by no means be placed at the lowest point of the separation container needs. Rather, it can also be in a slightly elevated position for example, attach to the side of the separation container. In last In the case, particularly heavy parts are not affected by the Discharge line discharged, but sink to the lowest Point of the separation container. There can be a separate discharge provided for these particularly heavy parts his.

The device for selective control is preferably a active conveyor, especially one with a drive provided pump. These include a. also provide with drive ne screw conveyor etc. (claim 2).

This active conveyor is preferably designed in this way det that the selective control of the withdrawn quantity without cross-sectional variation of the outlet line, only through Varying the delivery volume per unit of time. Here it can be, for example, a pressure piston pump, in particular a rotary lobe pump, such as for Conveying concrete is used. Such a rotary lobe pump pe can for example be designed so that the rotor is a catchy snail is in a two-course snail executes an eccentric rotary movement. Such a ge pump can be designed without a valve. Also a funding snail is suitable. The control of the withdrawn quantity is done by varying the volume of funding per unit of time  by changing the speed of the pump or Snail (claim 3).

Alternatively, the device for selective control of the withdrawn quantity also passively by using gravity be formed by, for example, the lower outlet line is formed as a flexible hose for control the discharge volume can be raised and lowered without cross-sectional variation is arranged (claim 4).

At the upper end of the separation container, an over is advantageous arranged running device to which the upper discharge line stung connects (claim 5). Through selective control The amount withdrawn below will be the amount of liquid level in the separation container - and thus indirectly above the overflow device overflowing amount - controlled.

Basically, the overflow opening can be a constant cross have cutting surface. However, it is advantageous with one Equipped for adjusting their cross-section (Claim 6). With finer plastic granules, namely a relatively small overflow opening area may be desired to a relatively large flow in the upper area of the separation container cause what is beneficial in terms of a Avoiding material buildup on the inner separation container effect. However, if there are larger parts in the mixture, about pieces of film are included, it is to avoid Blockages advantageous, the plant with a larger Drive overflow cross-sectional area.

At least one device is advantageous for process control device for determining the in the separation container per unit of time imported quantity and a facility for determining the Quantity removed from the separation container per unit of time below provided (claim 7). With these facilities it can be around independently operating flow or flow sensors act which is a partial or total constipation in the Supply line in the separation container or in the lower outlet Detect line directly. But it is also possible from the Speed of the respective feed pump towards the flow conclude. The latter type of investigation may be sufficient  if, in the event of constipation, the speed of the affected NEN pump reduced accordingly. The determined quantities serve to control the quantity withdrawn below - and thus indirectly also the amount withdrawn above. Furthermore, can the determined value of the introduced into the separation container Quantity also serve to control the feed pump, which for the transfer of the mixture from the stirred tank to the separator container is responsible.

As an additional measure to avoid or eliminate it any blockages can advantageously be a device for Introduction of pressure pulses into the lower outlet line be provided (claim 8). In particular it is compressed air pulses.

To prevent heavy goods contamination in front of the separation container (e.g. metal parts), the mixture leaves the Stirring container preferably laterally (claim 9). Metal part le, which in the stirred tank due to their great density sink below will not enter the separation container promoted.

To ensure even proportions in the preparation of the mixture To ensure, the system preferably has a facility device for determining and keeping the filling level constant Stirring container on (claim 10). It is also an advantage if the stirred tank has an agitator, the rotation of which number is regulated constantly (claim 11).

A first and a second are advantageous in the separation container Baffle provided, which are arranged horizontally, the Take up the cone between you and one to the side form directed flow space for the emerging mixture (Claim 12). Surprisingly, it has been shown that the characteristic measure a significant improvement Lich the variety purity of the separation can be achieved.

To avoid eddies in the separation container, this can be done Separating unit between the horizontal guide plates advantageous be equipped with vertical calming plates (Claim 13). A corresponding function can, however  for example also by radial ribs on the inside of the wall tion of the separation container are arranged can be achieved. At Foil material is more likely to be used from vertical calming plates apart from blockages at the outlet from the separation unit to avoid.

With regard to the procedural claims (claims 14-26) on the above statements on the various aspects and References of the plant.

The invention is now based on exemplary embodiments as well the drawing explained in more detail. The drawing shows:

Figure 1 shows a separation container in cross section.

FIG. 2 shows a side view of the separation container from FIG. 1 with a flexible hose for controlling the quantity removed below;

Fig. 3 shows a mixing tank in cross-section;

Fig. 4 is a schematic representation of a plant for the separation of substance mixtures; and

Fig. 5 is a view of another embodiment with stirring and separation container, in which the removal from the separation container is carried out by a pump.

The separation container 1 according to Fig. 1 and 2 is constructed of a kreiszy-cylindrical middle part 9 and an attached at its end faces conical upper part 10 and conical part 11. The transition from the cylindrical to the conical part of the stirring container 1 has, for example, an angle of 30-45 °.

The middle part 1 preferably has a width of 1.9-2.4 m. The separation container 1 has a total height of 4-6 m. At the center of the separating container 1 , a Trennaggre gat 3 is arranged, which consists of two cones with opposite tips, namely an upper cone 6 and a lower cone 7 , each with its base between two horizontal baffles, an upper baffle 4 and one lower guide plate 5 are used, built. In the case of one of the two cones 6 , 7 , the cone tip is actually missing because a pipe 2 opens in its place. So when above "with the tips facing" is hereby meant at one of the two cones 6 , 7 an "imaginary" tip ge. The cones 6 , 7 are arranged at a close distance from each other; For example, the distance between the tip of a cone and the opening surface of the pipeline 2 L 10 cm, in particular between 3 and 5 cm. A preferred arrangement is one in which the tips (one of which is "thought") touch.

The cones 6 , 7 have a cone angle 8 (measured at the cone tip) of 110-150 °, preferably approximately 120 °. The parallel baffles 4 , 5 are round and have a diameter of, for example, 0.7-1.1 m, preferably 0.8-1.0 m, thus reaching a distance of, for example, 0.3-0. 7 m, preferably 0.4-0.6 m to the wall of the separation container 1 . The distance between the guide plates 4 , 5 is, for example, 0.2-0.4 m, preferably approximately 0.3 m, and their diameter is, for example, 40-60% of the inside diameter of the separation container. The mixture is introduced into the separation container 1 from below or above through one of the cones 6 , 7 through the pipeline 2 . The corresponding cone 6 or 7 is therefore missing the cone tip because of the mouth of the pipeline 2 relative to the tip of the other cone 7 or 6 . The place where the center point of the connecting line of the two peaks or - with "touching" peaks is the (imaginary) point of contact is preferably the geometric center of the separating container 1 , so it is halfway up its center line. The baffles 4 , 5 form a defined geometric space, which represents a flow-related calming zone. Only after leaving this space at the outer end of the guide plates 4 , 5 does the mixture finally separate into the ascending light fraction and the descending heavy fraction, supported by partial flows of the separation medium leading upwards and downwards. In the area between the guide plates 4 , 5 there is a laminar flow to the outside. At the outer edge of the space formed by the baffles 4 , 5 , there may be several symmetrically arranged, vertical calming plates 29 between them .

The structural design of the separation unit 3 results in a laminar flow. The space between the guide plates 4 , 5 represents a quiet zone in which an optimal laminar flow is formed for the entry of the mixture into the separation container, which allows a sharp separation of the fractions of different densities after the exit. If the space between the guide plates 4 , 5 is chosen too small, a turbulent flow can develop. If it is chosen too large, the mixture would not be adequately guided in a laminar flow.

The diameter of the inlet tube 2 is relatively large ge selects to favor the formation of the laminar flow in the Trennaggre gat 3 . A too small diameter leads to a relatively high flow rate, which can have an unfavorable effect on the formation of the laminar flow. The distance between the cones 6 , 7 also has an influence on the laminarity of the flow. If the spacing is too small or too large, the laminarity and thus the separating effect will deteriorate.

At the lower end of the separation container, a lower outlet line 12 is attached through which the heavy fraction which has sunk to the bottom, together with a partial flow of the separation medium, is discharged. The amount dispensed below can be selectively controlled. In the exemplary embodiment according to FIG. 1, this control takes place by designing the lower outlet line 12 as a flexible hose which is led upwards to the level of the liquid level in the separation container and from there down again. The level of the highest point can be varied with a lifting and lowering device 13 which attaches to the highest point of the flexible hose. As a result, the liquid mirror in the separation container 1 can be raised and lowered according to the principle of the communicating tubes, whereby - in a manner explained in more detail below - the quantity withdrawn indirectly is also controlled. With the help of the selective control of the amount withdrawn below, it is controlled how the quantity introduced into the separation container 1 is divided into partial flows upwards and downwards in the separation container.

In the exemplary embodiment according to FIG. 5, the amount withdrawn below is actively controlled by a pump 44 . This is, for example, a rotary lobe pump, type PL-300 from Börger GmbH in D-16325 Borken. The quantity withdrawn is controlled by regulating the pump speed. By increasing and decreasing the volume flow of the pump 44 is - as in the first embodiment by raising and lowering the flexible hose - the liquid level in the separation tank raised or lowered, where indirectly controlled by the amount removed above.

Both embodiments have in common that the control of the quantity withdrawn below takes place without any cross-sectional narrowing of the lower outlet line 12 . In the first-mentioned embodiment, this is ensured in that the flexible hose is only adjusted in height, but its cross section remains unchanged. In the second embodiment, this is ensured by using a pump 44 which, for. B. "compartmentalized" promotes, the cross section of the "compartments" is not smaller than the cross section of the lower outlet line 12 . A valve 14 arranged at the beginning of the lower outlet line 12 is not used, for example, to control the quantity withdrawn by cross-sectional changes, but rather enables the separating container 1 to be shut off. It is e.g. B. a gate valve.

If the light fraction and the heavy fraction are present in approximately equal proportions in the mixture, the removal is electronically controlled by the lower outlet line 12 in such a way that approximately the same outlet quantities emerge from the separation container 1 above and below. If the proportion of the light fraction is significantly higher, more material is discharged via the upper outlet than through the lower one, which can be done by moving the flexible hose higher or reducing the amount conveyed by the pump 44 . In the case of a higher proportion of the heavy fraction, the flexible hose is lowered or the delivery rate of the pump 44 is increased, so that the amount discharged below is correspondingly larger than that discharged above. In all cases, this control is carried out without reducing the cross section, so that the occurrence of blockages is avoided.

At the upper end of the separation container 1 there is an overflow opening which is arranged in an overflow box 16 in which an upper outlet line 15 begins. From the upper opening of the separating container 1 has an opening cross-sectional area that can be adjusted in the range between 145 and 300 mm with an actuator. This opening is controlled in such a way that it is in the upper region when separating film material and in the lower region when separating granules. As a result, the greatest possible flow speed is achieved in the area of the overflow, so that the discharge can take place without material buildup and clogging.

According to FIG. 3, an agitator container open at the top with an opening cross section of 140-300 mm has an agitator 18 , which is equipped centrally in the middle or lower part of the container with at least one agitator, which is connected to the agitator 18 via an agitator shaft. The stirrer 19 is, for example, a stirring propeller with stirring blades, which can be designed to be adjustable. The stir-in container 17 is conically formed in its lower part. Approximately in the middle of the stir-in tank 17 , on one side of the cylindrical part, an outlet connecting line 20 opens, which connects the stir-in tank 17 to the separation tank 1 . At the lowest point of the conical part of the stirred-in container 17 there is an outlet slide 22 through which lowered heavy goods can be removed. The mixture of substances to be separated is input into the stirred tank 17 via a pipeline 32 . The input of the separation medium (it is, as will be explained in more detail below, recycled separation medium) into the return container 17 takes place via a return line 28 . The mixture of substances to be separated is initially introduced into the stirred-in container 17 which has already been flooded to 4/5 with separation medium. In the ongoing process, the introduction takes place in a constant flow, so that there is a concentration of 5-20%, preferably 10-15% by weight, based on the liquid phase, in the stirred tank. By means of the agitator 18 is a homogeneous mixture Herge provides, the stirring speed is set so that heavy contaminants, such as metal parts and foreign matter, sink into the conical lower part and the homogeneous mixture flows in laminar flow continuously through the side connection line 20 from while, while Contamination by the outlet slide 22 periodically, for. B. with a period of 0.1-1 h electronically controlled. The agitator 18 has an electronic speed control, by means of which the speed is kept constant regardless of the solids content of the mixture. The speed of the agitator is chosen so that turbulence in the liquid phase of the mixture is avoided. Furthermore, the filling level of the stir-in container is electronically monitored and kept constant by an electronic level control. A fill level sensor 21 ( FIG. 5) is provided for this. Referring to FIG. 5, a shut-off valve 35, a flow meter 36 and a pump 37 are disposed in the outlet connecting pipe 20 to the separation stage. A heavy goods cyclone 38 follows, from which heavy goods can be withdrawn via a heavy goods lock 39 which has not sunk downward in the stirred tank 17 . Finally, another flow meter 40 follows, until finally the connecting line 20 merges into the pipeline 2 , which opens into the separating unit 3 .

In the lower area of the separating tank 1, a valve is shown in FIG. 5 41 provided for discharging the separation container contents. The lower outlet line 12 is shortly after leaving the separation container 1 with a compressed air connection 42 , with which compressed air pulses can be conducted into the outlet line 12 . In other embodiments, instead of compressed air pulses, for example, separation medium pulses can be introduced. Further downstream, a flow meter 43 and the non-cross-sectional pump 44 are arranged in the lower exit line 12 .

The pumps 37 and 44 are connected to the flow and Durchflußmes sern 36 , 40 and 43 by a control such that a constant flow from the stirred tank 17 into the separation tank 1 and in the two discharge lines 12 , 15 from the separation tank 1 is regulated . In particular, it is indirectly known from the flow measurement in the connecting line 20 and the lower outlet line 12 which amount runs through the upper outlet line 15 per unit of time.

As a result, the distribution of the flow between the upper and lower outlet from the separation tank 1 is regulated to a constant value, which is selected depending on the ratio of light fraction to heavy fraction. For example, in the connecting line 20, a flow of 50 m ³ / h in the lower outlet line 12, a flow of 26 m ³ / h is kept constant, so that the flow in the upper outlet line 15 is indirectly regulated to 24 m ³ / h constant . A typical flow rate is 10-25 m ³ / h in the lower outlet line 12th With the aid of the flow meter 43 , partial or complete blockages in the lower outlet line 12 can be detected. In such a case, the control of the system causes 42 compressed air pulses to be introduced via the compressed air connection in order to eliminate a blockage. Such press pulses can also be given prophylactically in a constant sequence, for. B. 5-7 pressing pulses per minute. The selected flow rate is electronically controlled in such a way that it is so large that the separated fractions can be discharged from the separation container 1 without adhering and without attaching to the conical walls of the separation container 1 .

The shut-off valves or slide valves 22 , 35 , 42 can be actuated pneumatically via an electronic control. When the system is shut down, it is closed automatically by the control or opened automatically when it is started up.

A complete system and the overall process are now explained in more detail by the following example and FIG. 4.

In the stirred tank 17 , the ground to about 10-30 mm ground plastic mixture of plastic granules and / or foils, provenance "Green Dot", introduced through the inlet pipe 32 and with water introduced through the return line 28 as a separation medium with the stirrer 19 in homogenized at a concentration of about 10% kg plastic / kg separation medium. The homogeneous mixture is continuously introduced at a throughput of, for example, 1-1.2 t / h via the outlet connection line 20 and the pipeline 2 into the separation container 1 which has already been flooded with the separation medium. In the separating unit 3 , the separation of the heavy and light fractions begins in the laminar flow through the guide plates 5 and 6 . When leaving the space between the baffles 5 and 6 , the further separation into an ascending fraction with lower density and a descending fraction with greater density than the separation medium. After discharge from the separation container 1 through the upper and lower outlet lines 15 and 12 , these fractions are separated on sieves 23 and 26 and via filters 24 and 27 from the separating agent present in the liquid phase (for example water). If necessary, there is also a further drainage with a centrifuge 31 . Separated separating medium is passed into a buffer basin 25 and from there it is returned to the stirred tank 17 via the return line 28 .

For further separation of the light and / or heavy fraction these fractions can then use further separation stages run through, which in turn consists essentially of a stirred tank and separation container are constructed. The main difference of these subsequent separation stages is that in them the Separation medium heavier or lighter than that of the previous ones level.

The following fractions are separated using water as the separation medium:

The residual fractions can be separated in a corresponding step in a subsequent step using an MgSO ₄ solution as the separation medium.

In summary, the exemplary embodiments relate to processes for the continuous and non-clogging separation of mixtures of substances of different densities, in particular of plastic ground material from granules or foils by means of a separation medium by introducing the comminuted material into a stirred container for homogenization with the separation medium, pumping out into a separation container with a separation unit and exiting the separated ones Fractions and recycling of the separation medium. More specifically, the method illustrated by way of example has the following method steps:

• 1. Introducing the crushed mixture to be separated via the inlet pipe 32 into the liquid separation medium introduced separately through the return pipe 28 into the conical, already flooded stirring container 17 in a constant amount per unit of time, so that a concentration of 10-20, preferably of 10-15 weight percent, calculated on the liquid phase, is achieved, mixing to a homogeneous mixture by means of the agitator 18 with an agitator shaft with one or more stirrers 19 , such as, for. B. Stirrer propeller with adjustable Rührblät tern, the stirring speed is set so that contaminants, such as metals and foreign matter, sink into the conical, lower part and the homogeneous mixture in laminar flow continuously flows out laterally, approximately in the middle through the outlet connection line 20 and impurities are periodically removed by an outlet slide 22 ,
• 2. Entry of the homogeneous mixture in the Trennbehäl ter 1 , which is formed from the cylindrical part 9 and the upper and lower conical part 10 , 11 , through the pipe 2 just above the lower conical part 10 , which is in the middle of the cylindrical part 9 is formed bent vertically downwards, from this freely entering the separation unit 3 , which forms a geome mical space and is formed from an upper and a lower ren round or circular partition plate 4 , 5 , on which upper and lower cone 6th , 7 were arranged with a stand, with a cone angle 8 of z. B. 100-130 °, preferably from 120 °, and the cones with the tips in the sense explained above are closely opposed to effecting turbulence-free guidance of the homogeneous mixture in the liquid separation medium, as a result of which the swirling separation vessel 1 entering without swirling homo gene mixture of substances with a laminar flow speed causes a separation cut of the components with different density and only at the end of the separating plates 4 , 5 , which are optionally equipped with several vertical calming plates 29 , the substance particles of a comminuted grain size of 10-50 mm, preferably of 20-30 mm rise or fall into the conical parts 10 , 11 of the separation container 1 and thereby the material separation into one or more heavy fractions is effected, and a control of the liquid phase with the separated fractions through the opened valve 14 by means of a flexible hose 12 can be done, the z. B. by egg nen pulley 13 or a spindle drive is height adjustable, such that the upper curvature of the claw ches 12 as a communicating tube sets the same height with the liquid level in the separation container 1 , or, alternatively, by means of a pump 44 , the conveyance thereof quantity z. B. can be varied by adjusting the speed without changing the cross-section, so that the light fraction at the upper conical part 10 exits through the discharge pipe 15 with the overflow box 16 arranged therein and the heavy fraction exits in the lower conical part 11 of the separating container 1 , and the separated fractions Sieve dewatering 23 , 26 and filters 24 , 27 are separated from the liquid phase and this flows into a buffer basin 25 and from this the liquid separation medium is recycled via a return line 28 into the stirring container 17 , and the separated fractions are centrifuged and optionally a residual amount of the liquid phase is freed from after-drying and then silos are fed in for further use. When the system is at a standstill, the lower valve 14 remains closed until the throughput of the substance mixture is restarted, as a result of which the separation container 1 remains filled.

The diameter of the separating plates 4 , 5 is 0.4-0.6, preferably 0.47-0.5, in relation to the diameter of the cylindrical part 9 of the separating container 1 . For example, the diameter of the separating plates is 900 mm and the diameter of the cylindrical part 9 1900 mm.

The direction of flow and the amount of liquid separation medium at the upper outlet 15 and / or at the lower outlet 14 is effected by adjusting a variable height of the flexible hose 12 or controlling the delivery rate of the pump 44 by changing the height of the communicating liquid level in the separating container 1 . The diameter of the upper and lower outlet line 15 , 12 are the same, they are preferably 100 mm. The diameter of the inlet pipeline 2 is one to two times that of the outlet pipes 12 , 15 .

As a separation medium z. B. water or dissolved in water inorganic salts, such as NaCl, KCl, MgSO ₄ with a setting of different densities between 1.1 and 1.4 g / cm ³ or from water and water-miscible organic liquids, such as isopropyl alcohol with 0, Serve 80-0.98 g / cm ³ , the density of the liquid separation medium between the density of the light and the heavy fraction is adjusted.

After the light fraction has been separated off, further Separating containers in the same way, for. B. one or more heavy Fractions separated from the lighter fraction and treated in the same way.

The mixture of substances can be comminuted, for example, or by grinding to the ground material. Basically, it is possible to separate comminuted mixtures of materials such as ores, coal from gangue or metals, such as aluminum from iron, or immiscible liquids with different densities, such as water and oils. However, it is preferably an organic substance mixture, for example made of PE, PS, PVC, PET with a density of 0.96; 1.05; 1.30; 1.31 g / cm ³ , which are separated in several stages in separation containers in pure fractions. The plastics in pure fraction can be processed into granules by extrusion.

The separation container 1 has the following dimensions, for example:
Overall height 4 m, diameter of the cylindrical part 1.90 m, height of the cylindrical part greater than 2 m. With a throughput capacity of 1-2 t / h of the introduced plastic mixture, this can be separated into practically pure fractions.

An exemplary embodiment of the system has a conical stir-in container 17 with inlet pipe 28 for introducing the separation medium and inlet pipe 32 for introducing the comminuted mixture of substances, which has an agitator 18 with a stirrer shaft and stirrers 19 , such as, for. B. with stirring propellers with adjustable blades, to produce a homogeneous mixture and is connected to an outlet connecting line 20 for outlet of the homogeneous mixture on one side of the cylin drical part and is connected to an outlet slide 22 at the lower end of the conical part. From the outlet line 20 leads to the separation container ( 1 ), which comprises the cylindrical part 9 and the upper and lower conical parts 10 , 11 . In the separation container 1 , the separation unit 3 is arranged, which forms a geometric space that is delimited by the guide plates 4 , 5 , with cones from the upper and lower cones 6 , 7 in the above-explained sense at a short distance, such as, on the guide plates 4-5 cm, face each other, and wherein at the outer edge of the baffles 4 , 5 optionally vertical calming plates 29 are arranged. Through the curved pipe 2 , the homogeneous mixture enters centrally from below through the lower cone 7 and flows through these sheets at a laminar flow rate, so that the separating cut occurs at the round, preferably circular end of the guide plates 4 , 5 and the specifically lighter fraction or fractions via the discharge pipe 15 with overflow box 16 emerge and at the lower end the specifically heavier fraction or fractions emerges through the valve 14 and the flexible hose 12 that can be raised and lowered or the lower outlet line 12 equipped with the pump 44 . The Trennag gregat 3 is fixed in the cylindrical part 9 of the separation container 1 . The separated fractions are passed to the screening device 23 (lighter fraction) and the screening device 26 (heavier fraction) and then through filters 24 and 27 to separate the liquid separation medium. The separation medium flows into a buffer basin 25 and out of it via the return line 28 back into the stirred-in container 17 . The separated fractions are optionally dried by a centrifuge 31 and / or Heizvor direction and then fed to silos. If necessary, further fractions to be separated are inserted into a second stirring container 17 and separation container 1 .

On the circular edge of the guide plates 4 , 5 , several, in particular 12-15 stabilizing plates 29 are optionally arranged at an even spacing radially, and are welded to the plates 4 , 5 , for example, perpendicular to them. The diameter of the separation unit 3 is, for example, 900 mm, that of the cones 6 , 7, for example 500 mm, the cone angle measured at the tip is z. B. about 120 °, the distance between the cones 6 , 7 (in the sense explained above), preferably 4 cm, the Ab stood the parallel guide plates 4 , 5 about 300 mm, the diameter of the pipe 2, for example 110 mm, and the width of the Calming plates 29, for example 100 mm with an edge distance of approximately 20 mm.

The separation of the fractions of different densities in the liquid separation medium takes place in the separation unit 3 , which is formed by the parallel, round, circular or angular surfaces 4 , 5 in a defined space open to the sides, with the surfaces 4 , 5 in the interior the conical bodies 6 , 7 opposite one another are arranged with their bases, which serves to adjust the direction of flow of the liquid phase. Several vertical, radial, symmetrically arranged guide elements are attached between the surfaces, which serve to guide the laminar flow. When exiting at the ends of the parallel surfaces, the separating cut is effected, as a result of which the specifically lighter fraction or fractions flow out and the specifically heavier fraction or fractions sink, and these emerge at the upper and lower outlet openings. The separation medium is separated and recycled, the fractions are freed of residual water and fed to the silos.

With the method according to the invention, mixtures of substances with Variations in the solids content of about 5-50% solids, based on the homogeneous mixture separated with the separation medium become. The method has a large degree of selectivity Application range for the separation of inorganic or  organic mixtures of plastics in the form of granules laten and foils as regrind, from production waste from the Industry, preferably from the chemical industry and from waste management, the separation of carpets, fibers, Auto parts for recycling the separated materials as value fabrics. The process thus comes from a significant economist economic importance. The procedure has the return of fabrics a high cost-effectiveness with low Use of resources. It does not lead to environmental pollution gaseous, liquid or solid waste. The liquid separation medium is circulated. Provided aqueous solutions are to be removed from them, contain them in generally no toxic compounds, but mainly salts. The invention allows a reduction the waste to be disposed of by landfilling or incineration waste materials.

Finally, a list of reference numerals and various definitions of terms are given. The figures in the figures mean: 1 separation container
2 pipeline
3 separation unit
4 upper baffle
5 lower baffle
6 upper cone
7 lower cone
8 cone angles
9 cylindrical part of the separation container
10 upper conical part of the separation container
11 lower conical part of the separation container
12 lower outlet line (flexible hose connection in FIG. 1)
13 lifting and lowering device
14 pneumatic, electronically controlled exhaust valve
15 discharge pipe
16 overflow box
17 partially conical mixing bowl
18 agitator
19 stirrers
20 Outlet connecting line to the separation container
21 level sensor
22 pneumatic, electronically controlled outlet valve or outlet slide for foreign material
23 Upper drainage drainage
24 filters
25 buffer pools
26 Bottom drainage drainage
27 filters
28 Separation medium return line
29 calming plates
30 Line to the next separation stage
31 centrifuge
32 pipeline
35 shut-off valve
36 flow meter
37 pump
38 heavy duty cyclone
39 heavy goods lock
40 flow meters
41 drain valve
42 Compressed air connection
43 flow meter
44 pump

The terms are understood to mean:
liquid separation medium or liquid phase: the liquid whose density lies between the densities of the substances to be separated;
Fraction: This denotes the separated substances with different densities;
Pure fraction: denotes separated substances of the same chemical composition;
Particles: Designate parts of the material as granules or as regrind.

Claims (26)

1. Plant for the separation of substance mixtures with constituents of different densities by means of a liquid separation medium by rising light and falling heavy fractions, with:
a stirred tank ( 17 ) for producing a mixture of the mixture of substances and the separation medium,
at least one separation container ( 1 ),
a separator disposed in the container (1) Tren naggregat (3) through which the mixture is introduced into the separation tank (1),
Outlet lines ( 12 , 15 ) at the top and bottom of the separation container ( 1 ) for removing mixtures of light fractions and separation medium or of heavy fractions and separation medium,
characterized by at least one device for freeing these mixtures from the separation medium
a device for the selective control of the quantity of the mixture of heavy fractions and separation medium withdrawn per unit of time through the lower outlet line ( 12 ). 2. Installation according to claim 3, in which the device for the selective control of the amount withdrawn from the lower outlet line ( 12 ) is an active delivery device, in particular a pump. 3. Plant according to claim 2, wherein the active För dereinrichtung is designed so that it causes the selective control of the device through the lower outlet line ( 12 ) withdrawn quantity without cross-sectional variation by varying the delivery volume per unit of time. 4. Plant according to claim 1, wherein the device for selective control is formed by a configuration of the lower outlet line ( 12 ) as a flexible hose which is arranged for passive control of the amount of discharge without cross-sectional variation raised and lowered. 5. Plant according to one of claims 1 to 4, in which at the upper end of the separation container ( 1 ) an overflow device ( 16 ) is arranged, to which the upper outlet line ( 15 ) connects. 6. Plant according to claim 5, which has a device for adjusting the cross section of an overflow opening of the overflow device ( 16 ). 7. Installation according to one of claims 1 to 6, which also has the following:
at least one device for determining the quantity introduced into the separation container ( 1 ) per unit of time,
at least one device for determining the amount removed from the separation container ( 1 ) below per unit time,
wherein the device for selective control of the amount withdrawn per unit of time is controlled in dependence on the determined values of the amount introduced into the separating container ( 1 ) and the amount withdrawn from it below. 8. Installation according to one of claims 1 to 7, which comprises a device for the introduction of pressure pulses, in particular special compressed air pulses, in the lower outlet line ( 12 ). 9. Plant according to one of claims 1 to 8, in which a line for transferring the mixture produced in the stirred tank ( 17 ) into the separation tank ( 1 ) opens laterally into the stirred tank ( 17 ). 10. Plant according to one of claims 1 to 9, which comprises a device for determining and maintaining the degree of filling of the stirring container ( 17 ). 11. Plant according to one of claims 1 to 10, in which cher the stirred tank ( 17 ) has an agitator whose speed is kept constant. 12. Plant according to one of claims 1 to 11, in which cher in the separation container ( 1 ) a first and a second guide plate ( 4 , 5 ) are provided, which are arranged horizontally, the cone ( 6 , 7 ) between them and take form a laterally outward flow space for the emerging mixture. 13. Plant according to claim 12, in which between the horizontal guide plates ( 4 , 5 ) a plurality of vertical calming plates ( 29 ) are arranged. 14. A method for separating substance mixtures with constituents of different densities by means of a liquid separation medium by ascending light and sinking heavy fractions, with the following steps:

• Producing a mixture of the mixture of substances and the separation medium by stirring the mixture of substances into the separation medium in a stirring container ( 17 ),
• - introducing the mixture into a separation container ( 1 ) via a separation unit ( 3 ),
• - Removing the lighter fractions of the substance mixture including the separation medium at the top of the separation container ( 1 ) via an upper outlet line ( 15 ) and the heavier fractions below at the separation container ( 1 ) via a lower outlet line ( 12 ),
• Freeing the fractions separated in this way from the separation medium,

characterized in that the amount of the mixture of heavy fractions and separation medium withdrawn per unit of time through the lower outlet line ( 12 ) is selectively controlled. 15. The method of claim 14, wherein the selectively controlled removal of the mixture of heavy fraction and separation medium through an active conveyor tion takes place. 16. The method according to claim 15, wherein the selective control of the amount withdrawn through the lower outlet line ( 12 ) is effected without cross-sectional variation by varying the delivery volume per unit of time. 17. The method according to claim 14, in which the control of the bottom of the separation container ( 1 ) is carried out by lifting and lowering the lower outlet line ( 12 ) forming flexible hose. 18. The method according to any one of claims 14 to 17, in which with the control of the amount removed at the bottom of the separation container ( 1 ) also the liquid level in the separation container ( 1 ) is set, so that here also through the top of the separation container ( 1 ) via a there arranged overflow device ( 16 ) is influenced amount flowing. 19. The method of claim 18, wherein the cross intersection of an upper overflow opening in Ab dependence on the size of the solid components of the overflowing mixture of light fractions and Release agent is adjusted. 20. The method according to any one of claims 14 to 19, in which
the quantity introduced into the separation container ( 1 ) per unit of time is determined,
the quantity removed from the separation container ( 1 ) per unit of time below,
the quantity withdrawn per unit of time is controlled as a function of these determined values. 21. The method according to any one of claims 14 to 20, in which pressure pulses, in particular compressed air pulses are introduced into the lower outlet line ( 12 ) for the prevention or removal of blockages. 22. The method according to any one of claims 14 to 21, wherein the mixture is removed laterally from the Einrührbehäl ter ( 17 ), so that in the stirred tank ( 17 ) sinking parts are not transferred into the Trennbe container ( 1 ). 23. The method according to any one of claims 14 to 22, in which the degree of filling of the stirring container ( 17 ) is measured and kept constant by a control. 24. The method according to any one of claims 14 to 23, in which he stirring with the help of an agitator follows, whose speed is measured and by a rain tion is kept constant. 25. The method according to any one of claims 14 to 24, wherein the mixture flows laterally outwards after being introduced into the separation container ( 1 ) between a first and a second horizontal baffle plate which accommodate the cones ( 6 , 7 ) between them. 26. The method according to claim 25, wherein the outflow of the mixture from the space between the horizontal baffles ( 4 , 5 ) in the separation container ( 1 ) through a plurality of vertical calming plates ( 29 ) it follows.