WO1993023169A1 - Process and device for separating pulverized plastics of varying density - Google Patents

Abstract

Described is a process and a device for separating pulverized plastics of varying density using a flow. According to this process, a mixture of liquid and plastics of varying density is fed to a separting basin or the like. Flows are generated in at least two vertical planes by the admission of liquid in a channel (2) situated in the separating basin (1) and distributed over its length, and the liquid/plastic mixture, once it has passed through the separating basin (1), is fed into a collecting vessel (6) where the lighter plastics swimming at the surface of the liquid are drawn off or collected in a separate section of the vessel, while the heavier plastics sink to the bottom of the vessel and are removed there.

Description

 _ i _

Method and device for separating shredded plastics of different densities

Description:

The invention relates to a method for separating comminuted plastics of different densities with the aid of a flow and to a device for carrying out the method.

From DE 40 23 434 A1 a method for separating plastic materials is known, in which plastics that have been comminuted and partially mixed with foreign substances are fed together with a liquid to a flotation basin below its liquid surface, the liquid surface being constantly in with the help of a paddle wheel Movement is kept. As a result, the plastics floating on the surface of the liquid are driven to the end of the basin with a specific density lower than that of the liquid, where they are removed. The plastics with a specific density greater than or equal to that of the liquid are removed below the liquid surface through a funnel arranged on the pool floor.

In this method, a low inflow velocity is intended to prevent the heavier components from being lifted, so that they sink to the bottom of the pool, while the lighter plastic materials on the surface are transported by means of the paddle wheel to the end of the pool and be removed from there. However, a safe separation of the heavy plastics from the light plastics is not guaranteed, since the light plastics and the heavier plastics are often

REPLACEMENT LEAF fig stick to each other, so that the heavier plastics take the lighter plastics with them as they sink and there is therefore no separation.

The invention is therefore based on the object of achieving a method and a device for separating comminuted plastic particles of different densities with the aid of a flow, with which a reliable separation of different plastics is achieved.

This object is achieved according to the invention in that a mixture of liquid and crushed plastic materials of different densities is fed to a separation basin or the like, that in a channel or flow basin arranged in the separation basin, flows are distributed over their length by supplying liquid in at least two vertical planes are generated, and that the liquid-plastic mixture after passing through the separation basin is introduced into a collecting container in which the lighter plastics floating in the area of the liquid surface are removed or collected in a separate container section, while the heavier ones Plastic sink to the bottom of the container and be removed from there.

According to a preferred embodiment of the invention, the mixture of comminuted plastic materials and liquid is swirled through in a swirling stage before entering the separation basin in order to free the plastic particles from adhering foreign substances such as e.g. To separate air.

With the method according to the invention, a constant movement of the liquid-plastic mixture is therefore maintained over a longer flow path through the flows distributed over the longitudinal axis on two different levels.

REPLACEMENT LEAF ten, so that the lighter plastics possibly adhering to the heavier plastic materials float freely in the flow and thus have the possibility of floating upwards. Since this process is constantly repeated over the flow path, it is ensured that at the end of the flow path the heavier plastic particles have sunk downwards and the lighter plastic particles are located in the upper part of the channel. The light plastic particles are then removed in the collection container, for example by skimming. The heavy plastic particles collect at the bottom of the collection container. According to the invention, the liquid and possibly also the plastics can be returned to the swirling stage, so that an environmentally friendly method of working is ensured.

The device for carrying out the method is characterized in that a channel is formed in a separation basin, which channel consists of several channel sections arranged one behind the other, which are inclined downwards in the direction of flow, that nozzle arrangements are arranged in the channel over its length and that the last channel section opens into a collecting container adjoining the separation basin.

In a further development of this inventive concept it is provided that the nozzle arrangement has lower nozzles which are slightly inclined in their direction to the channel floor, while upper nozzles of the nozzle arrangement run essentially horizontally or are inclined slightly upwards. According to the invention, each nozzle arrangement can have nozzles which are arranged in a V-shape in the flow direction. This configuration of the nozzle arrangement ensures that a flow is always maintained over the entire channel cross section, both in the upper and in the lower region

REPLACEMENT LEAF becomes .

In order to be able to build the separation system as small as possible and still achieve a flow path of a certain length, according to a further embodiment of the invention, several channel sections can be arranged in a meandering manner one behind the other.

This can be achieved in a particularly simple manner in that the channel sections are formed by partition walls arranged in the separation basin.

According to a further embodiment of the invention, a swirl chamber is connected upstream of the separation basin. This expediently consists of a column-like container which has a lower inlet for the liquid-plastic mixture and an upper outlet for transfer into the separating basin.

In order to be able to collect the lighter and heavier plastics separated in the separation basin in a collecting container, a further development of the inventive concept provides that openings arranged one above the other in the container wall adjacent to the collecting container for introducing the lighter and heavier plastic particles into the collecting container ¬ are formed.

With the method according to the invention, a separation of plastic materials can be achieved to a degree which is sufficient in practice to be able to reuse the plastics. An even further fine separation may be desired for some plastics. This can be done by repeating the process by using several devices consisting of separation basin and collecting container,

REPLACEMENT LEAF can be switched in sequence. For large systems, several separating tanks with swirl chambers in front of each other can be arranged parallel to one another.

Further features, advantages and possible uses of the invention result from the following description of an exemplary embodiment and the drawing. All of the described and / or illustrated features, alone or in any combination, form the subject matter of the invention, regardless of how they are summarized in the claims or their relationship.

Show it:

1 shows a schematic representation of a top view of a device according to the invention for separating shredded plastics, FIG. 2 shows a section along the line II-II in FIG. 1, FIG. 3 shows a section along the line III-III in FIG. 1 and

4 shows a section along the line IV-IV in FIG. 1st

The device for separating crushed plastics essentially consists of a separation basin 1, in which a channel 2 or a flow path is arranged. The channel 2 consists of several channel sections 3, 3a, 3b, 3c. In the exemplary embodiment shown in FIG. 1, the individual channel sections are arranged in a meandering manner one behind the other. This is done in a simple manner by partitions 4, 4a, 4b, 4c. The lower sections 5, 5a, 5b, 5c of the channel sections 3, 3a, 3b, 3c are trough-shaped. The direction of flow of the liquid-plastic mixture is shown in FIG. 1 by arrows 17a.

REPLACEMENT LEAF Each channel section 3, 3a, 3b, 3c is inclined downward in the direction of flow, so that the last channel section 3c lies lower than the first channel section 3. This forms a kind of slide for the plastic parts. A collection container 6 is connected to the last channel section 3c. The collecting container is shown in more detail in FIG. 4. The last channel section 3c opens into a pre-collection container 6a formed by an intermediate wall 6d in the collection container 6, which has an inclined bottom surface 6b which opens into a post-collection container 6c which has a lower floor 7. The lighter plastic particles collect in the pre-collection container 6a, while the heavier ones sink to the bottom 7.

So that the heavier plastic particles can get into the collecting container 6, an opening 1c is made in a container wall 1a of the separating basin 1. Likewise, an opening 1b is made in the container wall 1 a for the lighter plastic particles. An outlet line 9 is provided in the area of the liquid level 8.

As shown in FIGS. 1 and 3, a swirling chamber 10a is arranged in front of the separating basin 1 with the channel 2 and consists of a columnar container 10 which has an inlet 11 at the bottom and an outlet 12 at the top. In the upstream swirling stage, the plastic particles should be free of adhering foreign substances, e.g. Air bubbles to be freed.

In front of the inlet 11 there is a feed channel 13 which has a transport device 1 which feed the comminuted plastic materials to a liquid channel 15, the liquid being conveyed by means of a pump 16.

ER && ZBL TT As can be seen from FIGS. 1 and 2, each channel section 3, 3a, 3b, 3c is assigned nozzle arrangements 17 distributed over its length, the nozzles 18 and 19 of which are arranged vertically one above the other. The nozzles 18 are located near the bottom of the channel 2, while the nozzles 19 are in the region of the water level. Liquid is applied to the nozzle arrangement 17 via the line 20. The direction of the nozzles 18, 19 runs in accordance with the flow to be achieved, which is indicated in FIG. 1 by arrows 17a.

The separation device works as follows:

A liquid is introduced via the pump 16 into the liquid channel 15, which is connected to the supply channel 13 for the plastic parts. The liquid-plastic mixture enters the inlet channel 11, which transports the mixture further into the swirling chamber 10a, which is designed as a columnar container 10. A swirl is caused by the fact that the columnar container 10 is larger in space than the inlet 11. The turbulence can be increased by the fact that the inlet channel is designed in the manner of a Venturi nozzle. The mixture is supplied in the lower region of the columnar container 10, while this mixture of liquid and comminuted plastic materials is supplied to the channel 2 formed in the separating tank 1 via the outlet 12 arranged at the top in the container 10. The nozzle arrangement 17 in each of the channel sections 3, 3a, 3b, 3c ensures that the mixture of liquid and comminuted plastic particles is kept in motion, so that the lighter plastic parts float upwards, while the heavier plastic parts sink downwards. The plastics floating on top are sprayed with the help of the nozzles 19 in each of the channel

REPLACEMENT LEAF sections 3, 3a, 3b, 3c transported further, while the sunken plastics are transported further with the help of the nozzles 18 in each of the channel sections 3, 3a, 3b, 3c.

Flows are thus generated in the channel 2 in two planes distributed over its entire length, which along the flow path ensure separation of the lighter plastic particles from the heavier plastic particles. The constant movement and swirling with the aid of the nozzle arrangement 17 in each of the channel sections 3, 3a, 3b, 3c ensures that lighter plastics adhering to the heavier plastics are separated so that they can float while the heavier ones sink down.

So that the area 2 is acted upon as far as possible, in particular the lower part of the channel, the nozzles 18 are arranged in a V-shape in the flow direction. In addition, nozzle arrangements of a similar type and guide devices, such as e.g. Baffles may be provided.

If the mixture of liquid and plastic particles has flowed through the last channel section 3c, the plastics have already been largely separated, so that the heavier plastic particles flow at the bottom of the channel section 3c while the lighter ones float above. The lighter plastic particles can be removed in a variety of ways, for example by a conventional conveyor, e.g. a scoop.

The heavier plastic particles collecting on the bottom in the last channel section 3c reach the collecting container 6 via the opening 1c and the post-collecting container 6c via the sloping bottom surface 6b, where they can be removed.

REPLACEMENT BLAL In the described procedure, the circuit is operated. The liquid conveyed with the aid of the pump 16, which takes along the plastic materials introduced from the feed channel 13, passes into the swirling chamber 10a and then into the channel system 2 and finally into the collecting container 6 and from there via the outlet line 9 ¬ back to the pump.

If a further fine separation is desired, the process can be repeated using the device consisting essentially of separation basin 1 with channel 2 sloping towards the front and collecting container 6.

REPLACEMENT LEAF

Claims

Expectations: 1. A method for separating crushed plastics of different densities with the aid of a flow, characterized in that a mixture of liquid and plastics of different densities is fed to a separation basin (1) or the like, that in a channel arranged in the separation basin (2) flows distributed over its length are generated by supplying liquid in at least two vertical planes, and that the liquid-plastic mixture after passing through the separation basin (1) is introduced into a collecting container (6) in which the liquid lighter plastics floating on the surface are collected or collected in a separate container section, while the heavier plastics sink to the container bottom and are removed there. 2. The method according to claim 1, characterized in that the mixture of comminuted plastic particles and liquid is swirled in a swirling stage before entering the separation tank (1). 3. The method according to claim 1, characterized in that the liquid is withdrawn from the collecting container (6) and, if necessary, is supplied again with plastic parts to the swirling stage or the separation basin. 4. Apparatus for carrying out the method according to one of claims 1 to 3, characterized in that in a separation basin (1) a channel (2) or a flow path is formed, the one or more consecutively arranged channel sections (3, 3a, 3b, 3c), which are inclined downward in the direction of flow, that nozzle arrangements (17) are provided in the channel (2) over their length, ER ^SA TZBLATT and that the channel (2) opens into a collecting container (6) adjoining the separation basin (1). 5. The device according to claim 4, characterized in that the nozzle arrangement (17) has lower nozzles (18) which are slightly inclined in their direction to the channel bottom. 6. The device according to claim 4 or 5, characterized gekennzeich¬ net that the nozzle arrangement (17) has upper nozzles (19) which are substantially horizontal or are slightly inclined upwards. 7. The device according to claim 4, characterized in that each nozzle arrangement (18, 19) has a V-shaped nozzle in the flow direction. 8. The device according to claim 4, characterized in that the channel sections (3, 3a, 3b, 3c) are arranged in a meandering shape. 9. The device according to claim 8, characterized in that the channel sections (3, 3a, 3b, 3c) are formed by partitions (4, 4a, 4b) arranged in the separating basin (1). 10. Device according to one of the preceding claims, characterized in that the separation basin (1) is preceded by a swirling chamber (10a). 11. The device according to claim 10, characterized in that the swirling chamber (10a) consists of a columnar container (10) having a lower inlet (11) for the liquid-plastic mixture and an upper outlet (12) for transferring into the Separation basin (1). IE 12. Device according to one of the preceding claims, characterized in that openings (1b and 1c) for introducing the lighter or heavier plastic particles into the collecting container (6) are provided in the container wall (la) adjoining the collecting container (6) . REPLACEMENT LEAF