GB1578428A

GB1578428A - Apparatus for the continuous treatment of solied synthetic plastics products

Info

Publication number: GB1578428A
Application number: GB25273/78A
Authority: GB
Original assignee: Maschinenfabrik Buckau R Wolf AG
Current assignee: BWS Technologie GmbH
Priority date: 1977-06-16
Filing date: 1978-05-31
Publication date: 1980-11-05
Also published as: FR2394333A2; PL207622A1; IT7824428A0; IT1158750B; PL110338B1; CS223869B2; DD136720A6; AT356037B; DE2727181A1; ATA304978A; FR2394333B2; DE2727181C2; CH629400A5

Abstract

The apparatus has an elongated washing tank (1), which has on one narrow side a material feed with subsequent washing zone (7) and agitator (13, 14) and on the other narrow side a removal zone (8), which is arranged upstream of an adjoining discharge device (25). The latter comprises a rotating screening drum (39), which is mounted transversely to the transporting direction of the products and conveys with its uppermost part, rising up slightly from the liquid surface (19), the products into a discharge channel (44). In this arrangement, the screening drum (39) rotates in a discharge tank (41), which on the liquid side reaches only to below the liquid level (19), and is provided at the height of its axis with an outflow opening (46). By means of the discharge device (25), arranged downstream of the removal zone (8) and connected to the latter on the liquid side, a continuous, fully automatic washing-process run-through operation can be achieved over a lengthy period of time. The main application area of the apparatus is the reprocessing of plastic scrap. <IMAGE>

Description

(54) APPARATUS FOR THE CONTINUOUS TREATMENT OF SOILED SYNTHETIC PLASTICS PRODUCTS (71) We, MASCHINENFABRIK BUCKAU R. WOLF AKTIENGESELLSCHAFT, a German company, of Grevenbroich, Lindenstrasse 43, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for the continuous treatment of soiled synthetic plastics products.

According to the present invention, there is provided an apparatus for the continuous treatment of soiled synthetic plastics products, including an elongate container, a stirrer mechanism in an upper region of the container and extending lengthwise thereof to cause, in use, a turbulence in a washing solution in the container, a first wall in the container to define a substantially turbulence-free zone in said solution and arranged to allow comminuted plastics products to migrate along the container from the turbulent solution to said zone, an inlet at one end of said container to supply soiled synthetic plastics products to said solution in a region remote from said substantially turbulence-free zone, and means to remove the cleansed products from said zone at the surface of said washing solution, said means comprising a rotatable screening drum mounted in a housing having a liquid discharge for the drum, said drum being mounted transversely of said container, a second wall adjacent said zone and defining one wall of said housing and being lower than an upper surface of said drum to allow the cleansed products and liquid to flow over said second wall and onto the surface of said drum, the drum lifting the products clear of the liquid level in use of the apparatus so that liquid can drain from the products through the drum surface.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accom p-anying drawings, in which: Figure 1 is a diagrammatic longitudinal section through an apparatus for washing soiled synthetic plastics products, Figure 2 is an enlarged diagrammatic longitudinal section of an extraction device shown in Figure 1, and Figure 3 is a section on the line IIIIII in Figure 2.

Referring to the drawings, the apparatus includes an elongate container 1 having end walls 2 and 3, between which are defined a washing zone 7 and an extraction zone 8. A stirrer mechanism which consists of parts 13 and 14 is provided inside the washing zone 7 to cause turbulence in a washing solution in the container. The washing zone 7 is separated from the extraction zone 8 by an intermediate wall having a fixed part 9 and a pivotable, adjustable partition 10 depending from it. In this way, a substantially turbulence-free zone in the washing solution in the container is provided. An inlet 18 is provided at one end of the container to supply soiled synthetic plastics products to the solution in a region remote from the substantially turbulence-free zone.

The washing zone 7 is separated from a collecting hopper 6 beneath the zone 7 by means of a bar grate 20. Draining of the hopper 6 and removal of dirt separated from the chips of comminuted plastics products is facilitated by means of a valve 36 at the bottom of the hopper 6.

An extraction device 25 is positioned adjacent a chip outlet side of the extraction zone 8 of the container 1. An upper edge 42 of the end wall 3 is arranged to be below an intended liquid level 19 in the contaner 1, so that liquid can flow from the discharge zone 8 over the edge 42 to the extraction device 25.

The extraction device 25 includes a housing 41 above which is a discharge duct 44, the duct 44 also extending back over the discharge zone 8. A-rotating screening drum 39 is mounted in the housing 41 transversely of the intended direction of flow of the chips, i.e. transversely of the container 1, and is so arranged that its upper surface projects slightly above the liquid level 19.

Tn the region of the upper edge of the screening drum 39, the housing 41 is closed by a guide plate 43 which lies above the liquid level 19 and consequently above the upper edge of the end wall 3, the guide plate 43 extending between the drum surface and a short discharge pipe 45 of the discharge duct 44.

The drum 39, which is mounted on a drum shaft 40, is intended to rotate in the direction of the arrow "A" (Figure 2) and the axial length of the drum 39 is such as to extend up to the end walls of the housing 41 which are not shown. The drum may be closed or open at its sides. In the example shown, the drum is open at its sides and one end wall of the housing 41 is provided with an annular opening 46, to which is connected a discharge pipe 47. Both end walls of the housing 41 may be provided with such an opening 46 and pipe 47 and the two pipes may be connected to a common transmission pipe. In another construction, for example, the discharge opening 46 may be arranged beneath the screening drum 39 in the base of the housing 41.

The chips which are cleansed in the washing zone 7 leave the zone 7 beneath the edge 11 of the partition 10 and pass into the extraction zone 8, in which they float upwardly within the washing liquid. Since communicating vessels are involved, the liquid level is practically the same, both within the washing zones 7 and within the discharge zone 8.

The chips which are carried upwardly are removed from the liquid, are taken up by the rotating screening drum 39 and are supplied to the guide plate 43, where they are detached from the drum. The liquid which is entrained by the chips drains into the screening drum 39, in which, in the example shown, it forms a liquid level at the height of the opening 46. The chips so drained of washing liquid are then supplied by way of the short pipe 45 to a further processing stage. This may, for example, be carried out by pneumatic means, by the short pipe 45 having connected thereto a fan or blower by which the chips are withdrawn by suction from the discharge duct 44.

The washing liquid extracted by the drum 39 is expediently supplied by means of a pipe 48, which is connected to the pipe or pipes 47, to a filter 49 or to an ion exchanger or another suitable cleansing unit to remove extremely fine foreign substances or chemical constituents and, so cleansed, is returned by way of a pipe 50 into the washing section of the apparatus. Return liquid purification by reverse osmosis or ultrafiltration is also visualised. By using a pipe union 51 the cleansed return water or other washing liquid may possibly be supplied together with fresh water or other washing liquid from a supply pipe to the extraction device 25 to rinse the chips removed from the zone 8.

If it is intended that comminuted synthetic plastics products of different colours should be washed separately from one another, it is desirable to have a rapid emptying of the washing apparatus before chips of a different colour are introduced to the apparatus for washing.

It is possible for a rapid emptying to be carried out, by those chips which are floating on the surface 19 of the liquid being flushed to the discharge point by means of a jet of liquid. For this purpose, a sloping nozzle (not shown) is provided in the end wall 2 above the liquid level 19, from which nozzle liquid is sprayed onto the chips. As liquid for this purpose, it is possible to use fresh water, returned water or other solution from the housing 41 or both.

So that the chips which are floating on the surface of the liquid are able to reach the discharge zone 8, the wall 9 separating the washing zone 7 and the discharge zone 8 must be capable of being removed. For this purpose, the wall 9 terminates at a distance above the liquid level 19 and it is only supports for the bearings 16, which can be supported by the wall 9, which are extended downwardly to below the liquid level 19. The adjustable partition 10 is pivotally mounted on the wall 9 so that the partition 10 may be swung to above the liquid level 19. As a consequence, the chips may be supplied directly to the screening drum 39.

Fresh water or other washing solution may be delivered by means of a pipe into a liquid distributor chamber 52 in the discharge zone, the chamber 52 being connected to the pivotable partition 10, and/or fresh water or other washing solution may be delivered via a pipe 29 into the washing zone 7 below the liquid level 19 or the washing solution may be supplied above the level 19. It is also possible to provide a bypass pipe in order to supply the fresh water or other washing solution to the pipe 51.

WHAT WE CLAIM IS: 1. An apparatus for the continuous treatment of soiled synthetic plastics products, including an elongate container, a stirrer mechanism in an upper region of the container and extending lengthwise thereof to cause, in use, a turbulence in a washing solution in the container, a first wall in the container to define a substantially turbulence-free zone in said solution and arranged to allow comminuted plastics products to migrate along the container from the turbulent solution to said zone, an inlet

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 1, and is so arranged that its upper surface projects slightly above the liquid level 19. Tn the region of the upper edge of the screening drum 39, the housing 41 is closed by a guide plate 43 which lies above the liquid level 19 and consequently above the upper edge of the end wall 3, the guide plate 43 extending between the drum surface and a short discharge pipe 45 of the discharge duct 44. The drum 39, which is mounted on a drum shaft 40, is intended to rotate in the direction of the arrow "A" (Figure 2) and the axial length of the drum 39 is such as to extend up to the end walls of the housing 41 which are not shown. The drum may be closed or open at its sides. In the example shown, the drum is open at its sides and one end wall of the housing 41 is provided with an annular opening 46, to which is connected a discharge pipe 47. Both end walls of the housing 41 may be provided with such an opening 46 and pipe 47 and the two pipes may be connected to a common transmission pipe. In another construction, for example, the discharge opening 46 may be arranged beneath the screening drum 39 in the base of the housing 41. The chips which are cleansed in the washing zone 7 leave the zone 7 beneath the edge 11 of the partition 10 and pass into the extraction zone 8, in which they float upwardly within the washing liquid. Since communicating vessels are involved, the liquid level is practically the same, both within the washing zones 7 and within the discharge zone 8. The chips which are carried upwardly are removed from the liquid, are taken up by the rotating screening drum 39 and are supplied to the guide plate 43, where they are detached from the drum. The liquid which is entrained by the chips drains into the screening drum 39, in which, in the example shown, it forms a liquid level at the height of the opening 46. The chips so drained of washing liquid are then supplied by way of the short pipe 45 to a further processing stage. This may, for example, be carried out by pneumatic means, by the short pipe 45 having connected thereto a fan or blower by which the chips are withdrawn by suction from the discharge duct 44. The washing liquid extracted by the drum 39 is expediently supplied by means of a pipe 48, which is connected to the pipe or pipes 47, to a filter 49 or to an ion exchanger or another suitable cleansing unit to remove extremely fine foreign substances or chemical constituents and, so cleansed, is returned by way of a pipe 50 into the washing section of the apparatus. Return liquid purification by reverse osmosis or ultrafiltration is also visualised. By using a pipe union 51 the cleansed return water or other washing liquid may possibly be supplied together with fresh water or other washing liquid from a supply pipe to the extraction device 25 to rinse the chips removed from the zone 8. If it is intended that comminuted synthetic plastics products of different colours should be washed separately from one another, it is desirable to have a rapid emptying of the washing apparatus before chips of a different colour are introduced to the apparatus for washing. It is possible for a rapid emptying to be carried out, by those chips which are floating on the surface 19 of the liquid being flushed to the discharge point by means of a jet of liquid. For this purpose, a sloping nozzle (not shown) is provided in the end wall 2 above the liquid level 19, from which nozzle liquid is sprayed onto the chips. As liquid for this purpose, it is possible to use fresh water, returned water or other solution from the housing 41 or both. So that the chips which are floating on the surface of the liquid are able to reach the discharge zone 8, the wall 9 separating the washing zone 7 and the discharge zone 8 must be capable of being removed. For this purpose, the wall 9 terminates at a distance above the liquid level 19 and it is only supports for the bearings 16, which can be supported by the wall 9, which are extended downwardly to below the liquid level 19. The adjustable partition 10 is pivotally mounted on the wall 9 so that the partition 10 may be swung to above the liquid level 19. As a consequence, the chips may be supplied directly to the screening drum 39. Fresh water or other washing solution may be delivered by means of a pipe into a liquid distributor chamber 52 in the discharge zone, the chamber 52 being connected to the pivotable partition 10, and/or fresh water or other washing solution may be delivered via a pipe 29 into the washing zone 7 below the liquid level 19 or the washing solution may be supplied above the level 19. It is also possible to provide a bypass pipe in order to supply the fresh water or other washing solution to the pipe 51. WHAT WE CLAIM IS:

1. An apparatus for the continuous treatment of soiled synthetic plastics products, including an elongate container, a stirrer mechanism in an upper region of the container and extending lengthwise thereof to cause, in use, a turbulence in a washing solution in the container, a first wall in the container to define a substantially turbulence-free zone in said solution and arranged to allow comminuted plastics products to migrate along the container from the turbulent solution to said zone, an inlet

at one end of said container to supply soiled synthetic plastics products to said solution in a region remote from said substantially turbulence-free zone, and means to remove the cleansed products from said zone at the surface of said washing solution, said means comprising a rotatable screening drum mounted in a housing having a liquid discharge for the drum, said drum being mounted transversely of said container, a second wall adjacent said zone and defining one wall of said housing and being lower than an upper surface of said drum to allow the cleansed products and liquid to flow over said second wall and onto the surface of said drum, the drum lifting the products clear of the liquid level in use of the apparatus so that liquid can drain from the products through the drum surface.

2. An apparatus as claimed in claim 1 and further comprising a product discharge duct arranged to be above the upper edge of said second wall to collect and discharge the drained products from the surface of said drum.

3. An apparatus as claimed in claim 2 and further comprising pneumatic means connected to said discharge duct to withdraw the products by suction from said discharge duct.

4. An apparatus as claimed in claim 1, 2 or 3, wherein said housing is provided with a liquid discharge pipe to drain liquid that has drained through the surface of the screening drum.

5. An apparatus as claimed in claim 4, wherein said liquid discharge pipe leads back into the part of said container where said turbulence is caused and/or back into said substantially turbulence-free zone.

6. An apparatus as claimed in claim 4 or 5, wherein a filter is fitted in said discharge pipe.

7. An apparatus as claimed in claim 5 or 6, wherein an ion exchanger or another cleansing unit is provided in said discharge pipe to remove fine foreign substances or chemical constituents from the liquid drained from said housing.

8. An apparatus as claimed in any one of the preceding claims, wherein said first wall includes a partition which is pivotally suspended from a lower edge of a fixed part of said first wall.

9. An apparatus as claimed in claim 8, wherein a liquid distributor chamber is connected to said partition to supply liquid to said substantially turbulence-free zone.

10. An apparatus as claimed in claim 9 as appendant to claim 5, wherein said discharge pipe is led into said liquid distributor chamber.

11. An apparatus as claimed in claim 8 or claim 9, or 10 as appendant to claim 8, wherein the lower edge of said fixed part of said first wall is arranged to be above the upper edge of said second wall.

12. An apparatus as claimed in claim 11, wherein said stirrer mechanism is suspended by supports depending from said fixed part of said first wall.

13. An apparatus as claimed in any one of the preceding claims, wherein a sloping nozzle is provided at the end of said container that is remote from said zone, this nozzle being provided to spray liquid onto the surface of a washing solution in the container to urge floating comminuted plastics products towards said zone to facilitate rapid discharge of said products from said container.

14. An apparatus for the continuous treatment of soiled synthetic plastics products, substantially as hereinbefore described with reference to the accompanying drawings.