RU2286519C1 - Continuous effect drier for milled polymer wastes - Google Patents

Abstract

FIELD: engineering of equipment for recycling thermo-plastic polymer wastes for repeated sue, in particular, engineering of devices for drying washed milled thermo-plastic polymers, immediately after discharge from washing equipment.

SUBSTANCE: continuous effect drier is made in form of centrifuge, containing body with rotating perforated drum mounted on it, centrifuge is combined with centrifugal wheel, provided with blades. On the axis of perforated drum, immobile shaft passes with rectangular blades mounted on it with an angle to its axis, and one-two screw coils. Screw is mounted on output from drum prior to centrifugal wheel, and blades are positioned at an angle to shaft axis so, that input edge of a blade is positioned on same line with output edge of previous blade.

EFFECT: simplified construction, decreased energy consumption, increased efficiency.

3 cl, 2 dwg

Description

The invention relates to equipment for the processing of waste thermoplastic polymers with a view to their reuse. In particular, to devices for drying washed, chopped thermoplastic polymers, immediately after they exit the washing equipment (the humidity of the polymers can reach up to 120% (wt.)).

Drying devices of various operating principles are known, for example, centrifuges, vacuum and vibration drying chambers, and the like.

A known drying apparatus [1], comprising a cylindrical chamber with a conical base connected to a screw feeder and having a gas distribution grill and a central pipe for the lower inlet of the primary coolant and an annular collector arranged around the chamber with chordal nozzles for introducing the secondary coolant, characterized in that for the purpose of the intensification of the process when drying the crushed materials in a layer of fluoroplastic balls, the screw feeder at the outlet is equipped with a perforated matrix with knives, stvuyuschimi with both its surfaces, and in the chamber under the set screw concave tray provided with a compressed air nozzle, disposed parallel to the lower generatrix of the tray, wherein the manifold tapers along the secondary fluid.

Known vibration dryer [2], containing a spring-loaded housing having supports on opposite sides and equipped with a vibration drive mounted on the side of the spring support, characterized in that the second support is hinged to simplify the design, and the vibration drive is of a pendulum type.

A device for drying and heat treatment of granulate with an inert gas flow [3], which is based on a shaft dryer described in A 2530304 and having a closed loop of hot inert gas. The proposed device has a square casing with 4 conical fittings - upper and lower for the passage of granulate and two side for the gas flow (the flows are perpendicular).

A patent is known [4], in which an apparatus is proposed that contains a chamber for supplying a coolant, a conveyor belt located in the chamber, along which a layer of wet material arriving at the conveyor from the feed hopper and dried, poured into the discharge hopper, as well as a discharge chamber under the conveyor belt conveyor. The installation is characterized by the additional placement of one or more scraper conveyors above the conveyor belt, capable of moving in the vertical and horizontal directions, with the adjustment of the angle of rotation in the horizontal direction. The installation can be used in chemical, food, light and other industries, providing energy savings in the work and intensification of drying of bulk materials.

Known centrifugal vertical dryer for drying polymer granules [5]. A feature of this dryer is the improved design of the rotor screw blade system, which provides the movement of the dried granules from the inlet to the outlet of the dryer. The blades contribute to the uniform distribution of granules in the dryer, which improves the efficiency of the dehydration process.

The patent [6] describes an apparatus for grinding and drying materials. The device has a cylindrical body with a conical bottom. Several devices are provided for loading processed material into the apparatus. One of these devices includes a cylindrical sleeve passing along the central axis of the apparatus through the entire body and partially through the bottom. This sleeve is used to control the degree of grinding of the material and is equipped with a damper. An air stream passes through the apparatus, which is a cyclone. By adjusting the degree of grinding, the required grinding fineness is achieved, and the product is gravitometrically unloaded into the collection tank.

A device for the dehydration of bulk material [7], for example, grain, consisting of a rotor mounted on a vertical shaft with blades, a shell rigidly connected by radial ribs, with a rotor of loading and unloading devices, a pipe for supplying air and venting moist air. Characterized in that in order to increase the efficiency of dehydration, the shell is made in the form of a series of truncated cones mounted one above the other with the formation of annular slots. The rotor has perforations over the entire height of its surface. The blades are mounted on the rotor with the ability to change the angle of their inclination to the axis of the rotor. A throttle is located in the nozzle for the removal of moist air.

Known dryer for bulk materials [8], containing a housing connected in the lower part to the pipe of the input of the coolant, loading and unloading device. One of the walls of the casing is made concave and tangentially mated to one of the walls of the coolant inlet pipe, and the opposite wall of the casing is made inclined.

Known auger sedimentary filtering centrifuge with a package of mounted plates [9]. A centrifuge with a rotor equipped with a drum casing and a screw shaft with a multi-auger screw blade for feeding the material to be centrifuged.

In the application [10], a centrifuge with a drum equipped with two cleaning discs is proposed. Cleaning disks for accelerated drainage of fluid from the centrifuge drum are equipped with outlet channels that communicate with the prefabricated chambers. Between the exhaust channels and prefabricated chambers, adjustable throttling devices with simple configuration are provided. The simplicity of the design and the high operational reliability of the centrifuge, as well as its economic and technological advantages, are noted.

The closest, from the known, technical essence and the achieved result is a continuous centrifuge [11], containing a casing, a rotating rotor with perforated walls mounted in it, made in the form of a box having a rectangular shape in cross section. Around the outermost walls of the rotor are mounted conveyor filter belts equipped with an individual drive. The water contained in the pulp, under the action of centrifugal forces, is filtered through moving filter belts, and the remaining product is carried up for discharge. By changing the speed of rotation of the rotor and the speed of movement of the filter belts, it is possible to achieve the necessary degree of dewatering of the pulp. The device is designed for the dehydration of fine pulps.

Almost all known drying units are designed to dry well-waking products, and it is very difficult to dry shredded, wet polymers, including shredded film. Drying such materials is a lengthy cyclic process. Moreover, the film pieces stick together, and the moisture contained between them can be removed either by squeezing or by separating the film pieces and then removing the moisture by evaporation. From the above review of patents, it follows that in most drying plants, the use of a coolant is provided, and this leads to an increase in energy consumption. While for further processing of washed, crushed polymeric materials, for example, by agglomeration, it is sufficient to dry them to a moisture content of 1-2% (wt.).

The purpose of the invention is the creation of a desiccant, simple in design, consuming a small amount of electricity, with which it would be possible to remove the main amount of moisture from the crushed waste of polymeric materials, including film, which, after drying, could be immediately sent for further processing.

The task is achieved in that the proposed dryer for wet shredded film and granular polymer wastes is made in the form of a continuous centrifuge containing a housing with a rotating perforated drum installed in it. A stationary shaft with rectangular blades and a screw (one or two turns) mounted on it at an angle to its axis passes along the axis of the perforated drum. Moreover, the screw is installed at the exit of the drum in front of the centrifugal wheel. The blades are located on the shaft at an angle to its axis so that the input edge of one blade is in line with the output edge of the previous blade. If this condition is not met, the drained material will not move along the drum to the screw. The screw serves as a kind of locking and conveying element. It prevents the exit of part of the water entering the centrifuge directly from the feed hopper to the centrifugal wheel, and, in addition, it conveys the dried raw materials to the centrifugal rotor blades. The blades can be mounted on the shaft with respect to each other in the same line and at an angle along the helix. The gap between the blades and the perforated drum should be no more than 0.2 mm, with such a gap the dehumidifier works stably. With a gap of more than 0.2 mm, particles of crushed polymer fall into it, and when the drum rotates, these particles are rubbed with blades to the perforated surface of the drum, blocking the perforation. Moreover, with a gap greater than 0.2 mm, it is possible to lock the blades and stop the drum due to the crushed polymer accumulated in the gap, this is especially true for film waste.

The width of the blades is inversely proportional to the angle α (90 °> α> 0), under which they are mounted on the centrifuge shaft: the larger the angle, the smaller the width of the blade and vice versa. The number of blades mounted on the shaft, with a decrease in this angle is proportionally reduced. If the blade width is not reduced with an increase in the angle, then the total surface of the blades in contact with the material to be dried increases, decreasing the productivity of the dryer, for example, increasing the width of the blade by 20% leads to a decrease in the throughput of the dryer by 50%. If the blade width is not increased with decreasing angle, this will also lead to a decrease in the throughput of the dryer.

The centrifuge is combined with a centrifugal wheel equipped with blades. The centrifugal wheel is designed to unload the dried material from the dryer. The dryer is equipped with a rotary drive of the perforated drum and centrifugal wheel, a hopper, a fitting for draining water from the dryer.

The dehumidifier works as follows. Shredded wet waste of polymer materials (for example, washed shredded film waste, PET containers, etc.) enters the loading hopper. When the perforated drum rotates, polymer particles with water under the action of centrifugal forces are thrown onto its surface, while water passes through the perforation and is discharged through the outlet in the dryer body. Particles of polymer fixed blades located on the shaft of the dryer, during rotation of the drum move along the axis of the drum to the screw. The polymer particles are transported by a screw to the centrifugal wheel, with the help of which the raw material is emitted from the dryer to the receiving container. Moreover, after moving the polymer with each blade, it is again pressed by centrifugal forces to the surface of the drum, while water from its surface is discharged into the dryer body and out through the nozzle. The auger prevents the release of part of the water and the polymer that has just entered the perforated drum. Thus, the particles of crushed polymer that came at the exit of the desiccant have a moisture content of 1.8-2%.

The invention is illustrated by drawings (see figures 1 and 2), where in figure 1: A - drying device, front view, B - drying device, side view, C - drying device, top view; figure 2: A - the blades are located in one line relative to each other, B - the blades are located at an angle relative to each other - along a helical line. In Fig. 1 and Fig. 2: 1 - a desiccant case, 2 - a perforated drum, 3 - a centrifugal wheel with blades, 4 - a shaft, 5 - blades, 6 - a drive for rotating a drum and a centrifugal wheel, 7 - a loading hopper, 8 - drain fitting, 9 - auger.

An example embodiment of the invention. The blades 100 mm wide are located on a shaft with a diameter of 110 mm, are installed at an angle of 60 ° to the axis of the drum shaft and relative to each other in one line, the gap between the blade and the drum surface is 0.1 mm. Screw - one and a half turns. The waste of shredded PET containers was dried after they left the washing equipment (initial humidity of about 50%). After the dryer, the moisture content of the PET containers is 1.8%.

Information sources

1. USSR copyright certificate No. 1423879, cl. F 26 B 17/10, declared 06/30/86, publ. 09/15/88.

2. USSR copyright certificate No. 1423880, cl. F 26 B 17/26, declared 01/06/87, publ. 09/15/88.

3. German application 19957664.5, cl. At 29 At 13/06, F 26 At 19/00, stated. 11.30.99, publ. 05/31/2001.

4. Patent of Ukraine 2001063986, cl. F 26 B 3/06, declared 06/12/2001, publ. 02/15/2002.

5. US patent 6467188, CL. F 26 B 17/12, F 26 B 17/24, declared 10.10.2000, publ. 10/22/2002.

6. US patent 425830, cl. At 02 From 19/06, the application. 04/20/95, publ. 02/04/97.

7. Copyright certificate 434996, cl. B 04 V 3/02, B 07 V 13/10, decl. 09/14/72, publ. 07/05/74.

8. Patent of Belarus (Belarus) 5533, cl. F 26 B 17/10, declared 03/14/2000, publ. 09/30/2003.

9. Application of Germany 10065060, cl. 04 V 1/20, 04 V 7/12, stated 12/27/2000, publ. 07/11/2002.

10. German application 19900667, cl. 04 V 1/04, 04 V 1/12, declared 01/11/99, publ. 07/20/2000.

11. Patent of Russia 2213626, cl. B 04 B 3/08 stated 04/02/2001, publ. 10/10/2003 (prototype).

Claims (3)

1. A continuous drier for crushed polymer waste, which is a centrifuge containing a housing with a rotating perforated drum installed in it, characterized in that the centrifuge is combined with a centrifugal wheel equipped with blades, and a stationary shaft passes along the axis of the perforated drum with an angle to its axis with rectangular blades and a screw, and the screw is installed at the outlet of the drum in front of the centrifugal wheel, the blades are installed at an angle to the axis of the shaft so that least one blade inlet edge is in line with the outlet edge of the preceding, wherein the gap between the blades and the perforated drum is not more than 0.2 mm, and the blade width is inversely proportional to the angle at which they are mounted on the shaft. 2. The dehumidifier according to claim 1, characterized in that the blades on the shaft are located relative to each other in a straight line. 3. The dehumidifier according to claim 1, characterized in that the blades on the shaft are located relative to each other at an angle along the helix.

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