SU952622A1 - Apparatus for granulating thermoplastic materials - Google Patents

Abstract

Extruded strands of thermoplastics are granulated under water in a granulator which is divided by a partition into a coolant supply chamber with a tangential inlet and a granules receiver with a tangential outlet. Louvres are provided in the partition and channels with an annular distributor pass coolant to guide vanes facing the cutter blade array. The sum of the cross-sections of louvres and channels is less than the coolant inlet cross-section. This eliminates any excessive cooling of the perforated plate and any possible freezing of the strands in the perforations. The cut granules are quickly removed and clogging by agglomeration has been avoided.

Description

The invention relates to devices for granulating thermoplastics, especially for granulation in water.

It is known that plastic rods emerging from the forming holes of a perforated plate in a plastic state are cooled by a cooler and, thereby, cutting by rotating knives into uniform granulate is ensured. For this purpose, the granulator body through the inlet pipe is completely filled with water and the chopped granulate is supplied with a stream of water through the outlet pipe to the device for separation and drying of the granulate. As shown, for example, in the laid out description of the FRG patent 1 454 754, the flow of the coolant occurs axially through the drive shaft, hollow, carrying the head of the knife, directly from the perforated plate or through the inlet pipe tangentially located on the side facing the perforated plate. granulating device bodies.

• However, due to the direct supply of the cooler to the perforated plate, it is very cooled, as a result of which the plastic rods in the forming holes can freeze and a large supply of thermal energy to the perforated plate is required.

In addition, the flow of granulate washed off the perforated plate, due to the unfavorable location of the outlet pipes at a greater distance from the perforated. the slab at the granulate body remains unnecessarily for a long time in it, which is often the reason for clogging due to the deposits of the granulate. Undesired granulate deposits, especially with low density granulate, lead to agglomeration of the granulate and thus to even larger deposits.

The purpose of the invention is, while maintaining the principle of granulation of plastic rods in water, to avoid excessive cooling and, thereby, failure of the perforated plate, and without delay to transport the granulate from the granulator body to avoid clogging due to agglomeration.

The objective of the invention is to provide a device for granulation [Rods of thermoplastics in water, the perforated plate of which the feed stream of the cooler is not directly affected, and the outlet for the cooler which is formed so that the shortest possible residence time of the granulate mixture and cooler in the granulator body.

According to the invention, the problem is solved in that the granulator body,. the cutting device surrounding in a known manner, by means of a partition, is divided into a chamber for receiving granulate and a chamber for supplying a cooler.

The chamber for supplying the cooler is provided with an inlet pipe located tangentially in the direction of rotation of the cutting device, and the chamber for receiving granulate is equipped with an outlet pipe located on the side facing the perforated plate also in the direction of rotation of the cutting device in relation to. A chamber for supplying a cooler is connected with a chamber for receiving granulate by means of oblique parallel and radially extending and in the direction of rotation of the cutting device parallel to or in the direction of the chamber for receiving granulate conically tapering slots in the partition.

In addition, the chamber for supplying the cooler is connected to the chamber for receiving granulate through the channels, as well as an annular distribution chamber and a blade ring located on the + holder of the cutting device with leading blades oblique with respect to the direction of rotation.

The total area between the exit. mi of slots in the partition and the cross-sectional area of the channels is less than the cross-sectional area of the inlet pipe for the cooler.

The principle of operation of the device is as follows.

The cooler is supplied through the tangential inlet to the chamber for supplying the cooler and through the slots in the partition, as well as through the channels, into the distribution chamber and from there through the blade to the chamber for receiving granulate separately.

Due to the small cross-sectional area of the slots and channels in comparison with the cross-sectional area of the inlet pipe, the cooler flow enters through the aforementioned holes through the aforementioned holes into the chamber for receiving granulate due to the increase in pressure and, thanks to the guides, which are oblique with respect to the direction of rotation of the cutting device, the slots in the partition the blades of the blade of the crown, leads to rapid rotation of the flow of cooler pumped into the chamber for receiving granulate.

The plastic rods emerging from the forming holes are cut into fine granules by means of a cutting device, discharged into a rotating cooler stream, and then immediately transported by a cooler stream through an outlet pipe located directly at the perforated plate from the granule receiving chamber.

Reliable release by washing of the perforated plate or knife from the granulate Provided by a part of the flow exiting from the blade ring, which rotates synchronously with the cutting device.

Due to the design of the cooler exit zone from the blade ring, which is advantageous from the point of view of technical aerohydrodynamics, it is achieved that part of the flow covers the chopped granulate and diverts it into the rotating cooler flow in the chamber for receiving granulate, but doesn’t, however, fall directly onto the perforated plate and Don't overcool her.

In FIG. 1 shows the granulator body (section AA in FIG. 2); in FIG. 2 - section BB in FIG. 1; in FIG. 3 is a section bb in FIG. 2: In FIG. 4 is a view D in FIG. 2.; in FIG. 5 granulator body, top view.

The device (Fig. 1) consists of a perforated plate 1 with moldings located in front of the exit from the extruder; holes 2. In front of the perforated plate 1 there is a cutting device consisting of knives 3, a knife holder 18 and a drive shaft 4. This device is surrounded by a granulator body 5, divided into a chamber day.

The granulator body 5 consists of a chamber for receiving granulate 6 and a chamber for supplying cooling water 7, separated from each other by a partition 8. The granulator body 5 (Figs. 1 and 5). has at the chamber for supplying cooling water 7 a relatively located inlet pipe 9 for entering the cooler, and at the camera for receiving granulate 6 is also tangentially located at the outlet pipe 10 for exiting the cooler with chopped granulate.

At the same time (Fig. 2), the inlet pipe 9 and the outlet pipe 10 are located tangentially to the granulator body 5 so that the cooler passes through the chamber of the granulator body 5 in the direction of rotation P of the knife holder 18. The size of the differences in the cross sections of the inlet pipe 9th output pipe 10 depends on the provided throughput granulation device abilities.

The partition 8 {[Figs. 2 and 31 is equipped with several oblique in the direction of rotation P of the knife holder 18; · splines 11. The chamber for supplying the cooler 7 is connected by channels 12 to the annular distribution chamber 13. On the drive wahu 4 on. the blade ring 14 moves, also in the direction of rotation P of the knife holder 18 with oblique guide blades 15 4 of FIG. 4), The outer ring of the blade crown 14 • is elongated by the end protrusion 16 and thus overlaps the annular fitting 17 at the distribution chamber 1 3.

The knife holder 18 in the exit zone of the cooler 19 of the guide ring 14 is formed from the point of view of technical aerohydrodynamics so that the exit stream of the cooler is diverted from the perforated plate in cooperation with the outer ring of the blade ring 14.

The device operates as follows.

A cooler or a conveying means, in particular water, is supplied through an inlet pipe 9 to a chamber for supplying cooling water 7. The cooler stream entering in this way is divided into a large part directed through the splines 11 in the partition and a smaller part directed through the channels 12, distribution chamber 13 and a crown of blades 14 into the chamber for receiving granulate 6.

Due to the smaller area of the slots 11 and the channels in the free section compared to the cross section of the inlet 9, the flow of cooler enters through the openings through the above-mentioned openings into the chamber for receiving granulate 6 at high speed and enters the chamber for receiving granulate 6 due to the oblique arrangement holes after a short time.

Due to the slots located obliquely with respect to the direction of rotation P of the knife holder 18 and the guide vanes 15 of the blade ring 14 arranged in the same direction, the cooler rotates in the same direction as the knife holder 18.

The plastic rods emerging from the forming holes 2 of the perforated plate are cut into small granulate by means of a rotating knife 3, discharged into a rotating flow of cooler and directly, after which they are transported through the outlet pipe 10 from the chamber for receiving granulate 6.

Since especially with high throughput capacity it is important to free the perforated plate 1 and knives 3 from the granulate, is there an additional supply of part of the coolant flow?

the channel through the channels 12, the distribution chamber 13 and the blade ring 14,) which, due to the location of the guide vanes 15, is rotated in the same direction as the knife holder.

Thanks to the aerohydrodynamic design of the knife holder 18 and the external. the ring of the blade ring 14, the part of the cooler exiting here does not directly fall onto the perforated plate 1, as a result of which the plastic rods in the forming holes 2 are not frozen and preferably serves to divert the chopped granulate to the rotating cooler stream.

An advantageous embodiment of the device for further increasing the speed and pressure of the cooler provides for a conically tapering design of the slots 11 in the partition 8 in the direction of the chamber for receiving granulate 6.

Claims (2)

The invention relates to devices for the granulation of thermoplastics, especially for granulation in water. It is known that plastic rods in the plastic state, coming out of the perforated plate forming holes, are cooled by a coolant in a plastic state and, thus, ensure that the rotating blades are cut into a uniform granulate. For this purpose, the granulator case is completely filled with water and cut into pieces T is supplied with a stream of water through an outlet to a device for separating and drying the granulate. As shown, for example, in the published description of the German patent 1 454 754, the flow of the cooler occurs axially through the drive shaft, made hollow, bearing the knife head, directly from the perforated plate or through the inlet nozzle located tangentially on the side of the housing facing the perforated plate granulating device. However, due to the direct under chi cooler to the perforated plate, there comes its strong cooling effect. as a result, the plastic rods in the forming holes may freeze and a large supply of thermal energy to the perforated plate is required. In addition, the flow of granulate washed out of the perforated plate due to the unfavorable location of the outlet nozzles at a greater distance from the perforated plate. The granule body stays unnecessary for a long time, which often causes blockages due to deposits. granules ta. Unwanted pelletizing, especially with low density granules, leads to agglomeration of the granulate and thus even more sediment. The purpose of the invention is to avoid excessive cooling and, while maintaining the principle of granulation of plastic rods in water. failure of the perforated plate, and without delay, transg porting the granulates from the granulator housing to avoid blockages due to agglomeration. The object of the invention is to create a device for scaling the thermoplastic rods in water, the perforated plate of which does not directly touch the flow of the cooler, and the outlet for the cooler of which is formed so that the residence time of the mixture of granule and cooler is obtained as short as possible. the body of the pellet torus. According to the invention, the problem is solved in that the granulator housing surrounding the cutting device in a known manner is divided by means of a partition into a chamber for receiving the granulate and a chamber for supplying a cooler. The cooler supply chamber is provided with an inlet nozzle located in relation to the direction of rotation of the cutting device, and the granule receiving chamber is equipped with an outlet nozzle located on the side facing the perforated plate also in the direction of rotation of the cutting device with respect to the coolant supply unit associated with the chamber for receiving the granulate by means of radially extending and in the direction of rotation of the cutting device oblique, parallel or in the direction of the chamber for the reception of the granulate conically uzhivayuschihs slots in the partition. In addition, a cooling chamber is connected to a chamber for receiving granulate through channels, as well as an annular distribution chamber and located on the legs; holder of the cutting device blade blade with leading blades oblique relative to the direction of rotation. The total area between the outlets of the slots in the partition and the area from the channels are smaller than the cross-sectional area of the inlet for the cooler. The principle of operation of the device is as follows. The cooler is supplied through a tangential inlet to the chamber for supplying the cooler and through the slots in the NEU campus, and also through the channels is fed into the distribution chamber and from there through the blade crown into the chamber for receiving the granulate separately. Due to the small cross-sectional area of the ishits and channels in comparison with the cross-sectional area of the inlet nozzle, the flow of the cooler enters the chamber through the holes through the holes to receive the granulate due to the increase in pressure and, due to the oblique direction of the slotting device the septum due to the guiding blades of the blade ring, the flow of the cooler injected into the chamber to receive the granulate is rapidly rotated. The plastic rods coming out of the forming holes are cut into small granules by means of a cutting device, diverted into a rotating coolant flow and then immediately transported by a coolant flow through an outlet nozzle located directly at the perforated plate from the granulate receiving chamber. Reliable release by washing the perforated plate or knife from the pellet is provided by part of the flow coming out of the blade ring, which rotates synchronously with the cutting device. Due to the advantageous technical aero-hydrodynamic design of the exit zone of the cooler from the blade ring, it is possible that part of the flow encompasses the cut granulate and leads it into the rotating flow of the cooler in the chamber to receive the granulate, but does not fall directly on the perforated plate and does not overcool it. FIG. 1 shows a granulator housing (section A-A in FIG. 2); in fig. 2 shows a section BB in FIG. one; in fig. 3 shows a section B-B in FIG. 2: In FIG. 4 is a view of FIG. 2.; in fig. 5 the body of the pellet torus, top view. The device (FIG. 1 consists of a perforated plate 1 with a forming section in front of the extruder; openings 2. Before the perforated plate 1 there is a cutting device consisting of knives 3, a cutter holder 18 and a drive shaft 4. This device is surrounded by a granulator casing 5 divided into two cells. The granulator housing 5 consists of a chamber for receiving granule b and a chamber for supplying cooling water 7, separated from each other by a partition 8. Granulator housing 5 (Figures 1 and 5). has a cooling water supply chamber 7 with respect to the located inlet 9 for cooling inlet, and a chamber for receiving granulate 6 also with respect to the outlet nozzle 10 for leaving the cooler with a cut granule. In this case (Fig. 2, the inlet 9 and the outlet 10 are located relative to the granulator housing 5 so that the cooler passes the chambers of the granulator housing 5 in the direction of rotation P of the holder 18. The difference in the cross sections of the inlet 9 and the outlet 10 depends on the provided capacity of the granulation device.; The partition 8 (FIGS. 2 and 3 is equipped with several oblique in the direction of rotation P of the cutter holder 18) slots 11. The chamber for supplying the cooler 7 is connected by channels 12 to an annular distributor The second chamber 13, On the drive waiu 4, is a blade ring 14, also in the direction of rotation P of the knife holder 18 with obliquely arranged guide vanes 15 HFig.4), the outer ring of the blade ring 14 is elongated by the end protrusion 16 and thus blocks the annular fitting 17 at distribution chamber 1 3. Knife holder 18 in the exit zone of the cooler 19 of the guide ring 14 is formed from the point of view of technical aero-hydrodynamics so that the output flow of the cooler is diverted from the perforated plate in interaction with the outer ring of the blade ring 14. The device works in the following way. Cooler or transporting means, in particular water, is fed through the inlet 9 into the chamber for supplying cooling water 7. The flow of coolant thus divided is divided into a large part, guided through the slots 11 in the partition, and into a smaller part, directed through channels 12, distribution chamber 13 and a crown of blades 14 into the chamber for receiving granules. b. Due to the smaller area of the splines 11 and channels in the free section compared to the cross section of the inlet 9, the coolant flow, due to an increase in pressure, enters the cut holes in the chamber for receiving granule 6 with a high envelope and enters the chamber for receiving granulate 6 due to the oblique arrangement of the holes after a short time. Due to the splines located obliquely with respect to the direction of rotation P of the knife holder 18 and the guide blades m 15 of the blade ring 1 spread in the same direction, the cooler rotates in the same direction as the Cutter 18. The bars of plastic coming out of the perforated forming holes 2 the plates are cut into fine granules by means of a rotating knife 3 are diverted into a rotating coolant flow and immediately afterwards are transported through the outlet of the 10th chamber of the chamber to receive granulate 6. Since but with a high carrying capacity, it is important that the perforated plate 1 and the knives 3 are released from the granule; a part of the flow of cooling bodies through the channels 12, the distribution chamber of the 13th vane rim 14, is additionally supplied due to the arrangement of the guide blades 15 is driven in the same direction as the holder. Due to the aerohydrodynamic design of the knife holder 18 and the outer ring of the blade ring 14, the outward part of the cooler does not fall directly onto the perforated plate 1, thereby preventing the plastic rods from freezing in the forming holes 2, and preferably serves to drain the chopped granulate. to the rotating flow of the cooler. Advantageously, the device for further increasing the speed and pressure of the cooler provides for a conically tapering design of the slots 11 in the partition 8 in the direction of the chamber for receiving the granulate 6. Claim 1. A device for granulating thermoplastics, especially for granulating in water, consisting of a perforated plate, a cutting device located in front of it, consisting of a drive shaft and a knife-holder with a knife, and a housing surrounding the cutting device with a tangentially located entrance and exit for cooler, characterized in that the body of the granulator 5 is divided by partitions 8 into the chamber for receiving granulate 6 and to the subsequent chamber for supplying cooler 7, the chamber for supplying cooler 7 provided with an inlet branch pipe located tangentially in the direction of rotation P of the drive shaft 4, and the chamber for receiving granule b on the side facing the perforated 1 is provided with an outlet nozzle 10, also located tangentially in the direction of rotation P of the output shaft, wherein the partition 8 has The splines 11, which run radially and are located obliquely relative to the direction of rotation P of the drive shaft 4, the annular distribution chamber 13 is equipped with an annular nipple 17, with the channels 12 located between the distributor Ks1 meter 13 and the cooler supply chamber 7 guide vanes 15, inclined towards the direction E of the drive shaft 4, and with an end projection 16, and the sum of the cross-sectional area of the outlets of the splines 11 and the sum of the Kangshov 12 are smaller than the area transversely cross section of the inlet 9. 2. A device according to claim 1, characterized in that the oblique slots 11 arranged in the partition run parallel or conically taper in the direction of the chamber for receiving the granulate. It is recognized as an invention according to the results of the examination carried out by the Office for the Invention of German Democratic Republic. ten AT -