Underwater pelletizing apparatus and method

Abstract

An underwater granulation apparatus includes: a template assembly having a melt inlet for supplying liquid melt and a melt outlet for discharging multiple melt strips into an adjacent cutting chamber; a cutting device for producing granular particles from the melt strips; a cutting chamber adjacent to the template assembly and capable of being filled with water or other liquid, the cutting chamber having at least one inlet for supplying water or other liquid into the cutting chamber and at least one granule outlet for discharging a mixture of water or other liquid and granules from the cutting chamber; the underwater granulation apparatus further includes at least one gas inlet connectable to a gas source for directly or indirectly supplying gas into the cutting chamber, such that the supplied gas can interact with the granules inside the cutting chamber.

Description

Cross-reference to related applications

[0001] This application claims priority to German Patent Application No. 10 2023 119 050.4, filed on July 19, 2023, the entire contents of which are incorporated herein by reference in their entirety for all purposes as if fully set forth herein. Technical Field

[0002] This application relates to an underwater granulation apparatus and an underwater granulation method for producing granulates or pellets from plastic melt (particularly polymer melt).

[0003] This application particularly relates to a granulation apparatus for producing granules from flowable, curable plastics, comprising: a die plate assembly having a melt inlet for supplying liquid melt and a melt outlet for discharging multiple melt strands into an adjacent cutting chamber; a cutting device for producing granulate particles from the melt strands; and a cutting chamber adjacent to the die plate assembly and capable of being filled with water or other liquid, the cutting chamber having at least one (water) inlet for supplying water or other liquid into the cutting chamber and at least one (water / ) granule outlet for discharging a mixture of water or other liquid and granules from the cutting chamber; this application also relates to a method according to the preamble of claim 9. Water is generally the preferred liquid, but other liquids or liquid mixtures may also be used. Background Technology

[0004] Granulation apparatuses and methods are known in the prior art, for example, as disclosed in the applicant's patent applications EP 3 711 923 A1 or EP 3 915 747 A1. In such underwater granulation apparatuses, a plastic, also known as melt, which becomes flowable by heating, is supplied to a die assembly including a template having multiple fluid channels. A strip of liquid melt passes through the template, adjacent to a water-filled cutting chamber. The melt strip flowing from the orifices of the template is separated into individual melt pellets or granules by blades in contact with the template and typically rotating, and discharged into the cutting chamber (also known as a "water tank"). The individual pellets come into contact with water in the cutting chamber, thereby forming individual pellets or granules that solidify over time. Water is continuously supplied to the cutting chamber. The granules are cooled and solidified in the process of contact with water.

[0005] The resulting granules are conveyed out of the cutting chamber via a water flow in a two-phase flow of water and granules. To accelerate the discharge of the water / granule mixture from the cutting chamber, WO2009 / 155196 proposes introducing air into a conveying pipe downstream of the granulation unit to expedite the transport of water and the produced granules to a centrifugal dryer. Upon discharge, the granules separate from the water and are dried in a drying process. The resulting granules can then be melted and used in the manufacture of plastic products, such as in injection molding processes and injection molding machines, or in production processes (e.g., as a liquid binder).

[0006] The particles or granules formed after being discharged from the template and cut in the cutting chamber have irregular shapes and are more or less elongated, partially curved to round or elliptical. In many cases, the goal is to approximate a spherical shape, as this has advantages in terms of crystallinity, flowability, and transport bulk density.

[0007] The purpose of this application is to provide a granulation apparatus and granulation method for producing granules or pellets in an underwater granulation process, so as to improve the shape of the granules in the cutting chamber, in particular to make the produced granules close to spherical.

[0008] This application achieves the above-mentioned objective through the granulation apparatus according to claim 1 and the method according to claim 9. Summary of the Invention

[0009] In the granulation apparatus of this application, and similarly in the method described herein, at least one gas inlet connectable to a gas source is provided for directly or indirectly introducing gas into the cutting chamber, allowing the directly or indirectly introduced gas to interact with the granules inside the cutting chamber. According to this disclosure, the gas directly or indirectly introduced into the cutting chamber moves in the water within the cutting chamber and interacts with initially slightly flowable granules discharged from the template assembly and floating in the water of the cutting chamber (water tank), which subsequently cool and solidify. Upon introduction into the cutting chamber, the gas typically forms bubbles, which, in addition to being acted upon by the water flow introduced and passing through the cutting chamber, are also driven upwards by buoyancy in the water. These bubbles can contact the granules, influencing their movement in the water and potentially causing additional mixing motion, etc. According to this application, the overall result is that, during the solidification process, the granules in the cutting chamber acquire a more rounded, uniform, and homogeneous shape than in the prior art. The introduced gas can also advantageously influence the spherical or elliptical size and homogeneity typically desired in the formed granules. According to this application, the overall quality of granules can be improved in underwater granulation processes due to the three-phase flow or movement of gas / water / particles within the cutting chamber. According to this application, the introduction of gas into the cutting chamber enables the production of granules or pellets with superior performance; in particular, the direct or indirect introduction of gas into the cutting chamber according to this disclosure allows the produced granules to more advantageously approach a compact, particularly spherical, shape, or even ideally achieve a spherical shape. Another advantage of the granules being closer to a spherical shape according to this application is that, for example, when using polyethylene terephthalate (PET) plastics, less energy is required for subsequent liquefaction of the granules because the subsequent crystallization behavior of the granules is improved. By approaching a spherical shape, the produced granules or pellets acquire higher internal heat, resulting in higher crystallinity or higher crystallinity, which is advantageous for further processing of the granules in plastic processing systems, especially during melting processes. Due to the introduction of gas, the process can also be performed better when deviating from the original optimal operating mode, and wear between the blade and the die or clogging of the nozzle orifices in the die can also be reduced.

[0010] The gas is preferably air, but other gases or gas mixtures may also be used. Air is preferably from a compressed gas source. Thus, the introduced gas, in the form of bubbles typically generated, provides another factor influencing the plastic curing process. The amount of gas introduced into the cutting chamber according to this application (e.g., measured by volumetric flow rate or mass flow rate) can also serve as another variable in the curing process, used to specifically influence the curing process to produce particles of the highest possible quality and homogeneity. According to this application, the gas introduced into the cutting chamber may also trigger chemical reactions, whether the gas molecules react with the plastic molecules, etc. As an alternative to air, according to this application, other gases or gas mixtures may be introduced directly or indirectly into the cutting chamber, such as inert gases, argon, nitrogen, etc., preferably gases that do not react with the molecules contained in the particles. Another alternative is to introduce liquids other than water directly or indirectly into the cutting chamber, such as mixtures comprising water and other liquids.

[0011] According to one embodiment of the granulation apparatus of this application, a gas nozzle assembly connectable to a gas inlet is provided. This gas nozzle assembly has multiple nozzle orifices for directly or indirectly discharging gas into a cutting chamber. The gas nozzle assembly is disposed directly inside the cutting chamber or within a (water) supply channel connected to the cutting chamber, enabling the formation of a large number of bubbles in the cutting chamber, which can be filled with water or other liquids. This gas nozzle assembly supports bubble formation, for example, generating a large number of microbubbles that subsequently interact strongly with particulate matter in the cutting chamber.

[0012] According to another embodiment, the gas nozzle assembly is arranged upstream of the outlet of the cutting chamber, preferably directly inside or at the cutting chamber, or indirectly inside or at the (water) supply channel, preferably inside the (water) supply pipe. In this way, gas can be introduced into the cutting chamber either directly or cumulatively. This advantageously enables the formation of a large number of bubbles, which subsequently interact strongly and advantageously with the cut particles introduced into the cutting chamber. Due to the buoyancy of the gas (preferably air) in the flowing water, the velocity components of the flowing water and the buoyant gas can be superimposed, resulting in bubbles entering the region where the particles are suspended in the water at increased velocity, which can affect particle formation. This can have a further positive impact on the homogeneity and quality of the formed particles. According to this application, the formed particles are closer to a compact shape, particularly an ideal sphere, although sphericity is generally only a desired goal and is rarely achieved precisely in practice. Experiments show that this application achieves an improved approximation to a spherical or compact shape compared to the prior art. According to this application, the roundness of the particles is improved.

[0013] Therefore, it is advantageous that the gas nozzle assembly is arranged below the template assembly.

[0014] Another embodiment of this application features a gas nozzle assembly disposed within a water supply pipe forming a water supply channel, the water supply pipe preferably being generally vertically oriented and preferably disposed generally below the template assembly, supplying a water / gas mixture to the cutting chamber during operation. This allows for the strong and uniform formation of a large number of bubbles in the water supply area, thereby achieving a strong interaction between the bubbles floating in the water flow and the particles in the solidification process. A very simple design is achieved by using a (water) supply pipe in which the gas nozzle assembly is disposed, and gas connections in the immediate vicinity of the cutting chamber are avoided.

[0015] According to an advantageous improvement of this application, in order to achieve a favorable and intense mixing of bubbles and particles, the melt outlet of the template assembly is arranged such that the granular particles and the water / gas mixture move at least partially toward each other inside the cutting chamber at an angle of approximately 60° to 120°, preferably at an angle of about 90°.

[0016] The granulation apparatus is preferably designed such that a water / granule discharge channel for discharging the granule / water / gas mixture is arranged above the cutting chamber. This discharge channel is preferably tubular and at least partially arranged substantially vertically to discharge the granule / water / gas mixture during operation and further convey it for particle separation and drying.

[0017] By supplying a high volumetric flow rate of gas and designing the gas nozzle assembly as an annular nozzle, bubbles can be formed particularly strongly.

[0018] The aforementioned advantages are achieved to the same extent by an underwater granulation method for producing granules from flowable, curable plastics, preferably using the granulation apparatus of this disclosure. The method of this application includes the following steps: supplying liquid plastic in melt form to a template assembly having a template, and discharging it from the template in the form of multiple melt strips through multiple flow channels in the template; dividing the discharged melt strips into individual granular particles by a cutting device; discharging the granular particles into a cutting chamber filled with water or other liquid; introducing water or other liquid into the cutting chamber through at least one (water) inlet; and conveying the water or other liquid and granules out of the cutting chamber through at least one outlet; wherein gas is introduced into the cutting chamber through a gas inlet, such that the gas interacts with the granular particles inside the cutting chamber filled with water or other liquid. For the avoidance of repetition, reference is made to the above description of the apparatus regarding the technical effects and advantages.

[0019] Preferably, gas is supplied through a gas inlet to a gas nozzle assembly having multiple nozzle orifices connected to the gas inlet; the gas is discharged from the nozzle orifices into the cutting chamber to form a large number of bubbles inside the cutting chamber or inside the (water) supply channel connected to the cutting chamber; and the bubbles interact with the granular particles in the cutting chamber, thereby affecting their shape as the granules or particles solidify, which advantageously results in higher compactness or roundness of the particles.

[0020] Furthermore, gas is introduced upstream of the cutting chamber outlet via a gas nozzle assembly, preferably directly inside or at the cutting chamber, or indirectly inside or at the (water) supply channel. Preferably, the gas nozzle assembly is arranged below the template assembly and / or introduces gas into a (water) supply pipe forming the (water) supply channel via the gas nozzle assembly. This (water) supply pipe is preferably generally vertically oriented and preferably arranged generally below the template assembly, supplying a water / gas mixture to the cutting chamber during operation.

[0021] In one aspect, an underwater granulation apparatus includes: a template assembly having a melt inlet for supplying liquid melt and a melt outlet for discharging multiple melt strips into an adjacent cutting chamber. The underwater granulation apparatus also includes cutting equipment for producing granular particles from the melt strips. The underwater granulation apparatus further includes a cutting chamber adjacent to the template assembly, the cutting chamber being capable of being filled with water or other liquid, having at least one (water) inlet for supplying water or other liquid into the cutting chamber, and having at least one (water) granule outlet for discharging a mixture of water or other liquid and granules from the cutting chamber. The underwater granulation apparatus further includes a gas inlet connected to a gas source for directly or indirectly supplying gas into the cutting chamber, such that the supplied gas can interact with the granules within the cutting chamber.

[0022] Therefore, certain aspects of this application have been summarized in general terms to better understand the detailed description herein and to better recognize its contribution to the art. Of course, other aspects of this application will be described below, and these aspects will form the subject matter of the appended claims.

[0023] In this regard, before explaining at least one aspect of this application in detail, it should be understood that this application is not limited to the structural details and component arrangements set forth in the following description, nor is it limited to the structural details and component arrangements shown in the accompanying drawings. This application can be implemented and performed in other aspects besides those described. Furthermore, it should be understood that the wording and terminology used herein, as well as the abstract, are for descriptive purposes only and should not be considered restrictive.

[0024] Therefore, those skilled in the art will understand that the concepts upon which this disclosure is based can be readily used as the basis for designing other structures, methods, and systems for achieving the various objectives of this application. It is therefore important that the appended claims be considered to include such equivalent constructions, provided they do not depart from the spirit and scope of this application. Attached Figure Description

[0025] This application will now be described by way of reference to embodiments and accompanying drawings, wherein: Figure 1 : A schematic diagram showing a first embodiment of the granulation apparatus and granulation method; Figure 2 : A perspective view showing a second embodiment of the granulation apparatus; Figure 3 : Show Figure 2 Side view of the granulation device in the middle; Figure 4 : Shows a partially enlarged side view of the granulation apparatus, in which bubbles are shown; Figure 5 : Shows a front view of the granulation apparatus; Figure 6 : Shows a cross-sectional view of the granulation apparatus; Figure 7 : Shows a portion of a granulation apparatus with a gas nozzle assembly; Figure 8 : Show Figure 7 A partial sectional view; Figure 9 : This illustrates a portion of a granulation apparatus having a gas nozzle assembly according to an alternative embodiment; Figure 10 : Show Figure 9 A partial sectional view; Figure 11 : This illustrates a portion of a granulation apparatus having a gas nozzle assembly according to another embodiment; Figure 12 : Show Figure 11 A partial sectional view; Figure 13: Shows the pellets produced in the first experiment without air circulation, according to the prior art; Figure 14 : This shows the pellets produced in the apparatus of this application according to the method of this application in a first experiment; Figure 15: Showing the pellets produced in the second experiment under non-aeration conditions according to existing technology; and Figure 16 : This shows the pellets produced in the apparatus of this application according to the method of this application in a second experiment. Detailed Implementation

[0026] Figure 1 as well as Figures 2 to 12 The two embodiments shown illustrate an underwater granulation apparatus 1 and a method for producing granules 3 or pellets 3 from a flowable, curable plastic (e.g., a polymer), the apparatus also referred to as a granulator 1. Figure 1 and Figure 4 A large number of particles or granules 3 are illustrated schematically. In both embodiments, the same or substantially the same parts and components use the same reference numerals.

[0027] exist Figure 1 and Figure 2 The granulation apparatus 1 shown includes a template assembly 6, known in the prior art, which typically has a perforated disc with multiple cylindrical channels. This template assembly has a melt inlet 8 for supplying liquid melt and a melt outlet for discharging multiple melt strips into an adjacent cutting chamber 2. The cutting chamber 2 is also referred to as a water tank 2 because it is filled with water flowing through it during operation. Other liquids or fluid mixtures may also be used instead of water in apparatus 1.

[0028] Cutting equipment 12 ( Figure 1 Not shown in the image, but... Figures 2 to 6 (As shown in the figures and described in more detail with reference to these figures) includes a drive mechanism and a blade rotatable by the drive mechanism for producing individual pellets 3 particles from a molten material strip discharged from a die assembly 6, preferably having a perforated disc, into a cutting chamber 2 (adjacent to the die assembly 6 and potentially filled with water or other fluid). The cutting chamber 2 has at least one water inlet 14, preferably arranged in the lower region, for indirectly (in this example) supplying water to the cutting chamber 2, and at least one water / particle outlet 16, arranged in the upper region, for discharging a mixture of water, pellets, and gas from the cutting chamber. The water inlet 14 of the cutting chamber 2 is connected to a water supply pipe 38, which forms a water supply channel 36 for supplying water to the cutting chamber 2. The outlet 16 in the upper region of the cutting chamber 2 is connected to a water / particle discharge pipe 18 through which the pellets 3, along with water and gas, can be discharged upwards and supplied to a separator known to those skilled in the art for separating the produced pellets 3 from the water, and preferably to a dryer (not shown) for drying the produced pellets 3.

[0029] Figure 1 More specifically, based on Figures 2 to 11An initial example shows a device 1 having at least one gas inlet 19 connectable to a gas source (not shown) for introducing gas into a cutting chamber 2, such that the introduced gas, particularly preferably in the form of moving bubbles, can interact with the granules 3 inside the cutting chamber 2. In an embodiment, the gas inlet 19 is arranged inside a water supply pipe 38 connected to the cutting chamber 2, such that the introduced gas can be indirectly introduced through the supply pipe 38 and then directly introduced into the cutting chamber 2 through inlet 14, in this embodiment, in the form of a water / gas mixture flowing through the water supply pipe 38 and inlet 14 into the cutting chamber 2. The scope of this application also includes the possibility that gas can be introduced into the cutting chamber 2 through a gas inlet 19 located inside the cutting chamber 2 or through a gas inlet 19 formed in the wall of the cutting chamber 2, and introduced from a gas source during operation. The introduced gas is preferably air, and preferably forms a large number of bubbles that are indirectly introduced into the cutting chamber 2 through the supply pipe 38 as shown, or directly introduced into the cutting chamber 2 as described, where they interact with the particles of the granules 3.

[0030] Water or other liquids can be pumped from the reservoir through, for example... Figure 1 and Figure 4 The (water) connector 40, as shown, initially supplies water in a single-phase flow, as indicated by arrow 39, preferably upward through the vertical supply pipe 39. The gas inlet 19 connects to a gas nozzle assembly 20 with multiple nozzle orifices 44 for discharging gas into the cutting chamber 2. In an arrangement not shown, the gas nozzle assembly 20 may be arranged inside the cutting chamber 2, or, as shown in the embodiment, inside the (water) supply channel 36 formed by the supply pipe 38 and connected to the cutting chamber 2; in both cases, it is preferable to form a large number of bubbles 24 in a water-fillable cutting chamber. Here, the airflow, indicated by arrow 41 and in the form of bubbles 24, flows together with the supplied water (arrow 39) in a two-phase flow through the supply pipe 38 and inlet 19 into the cutting chamber 2, where it can interact with the produced small particles 3. Then, as indicated by arrow 43, the granule 3 flow, together with water and gas, flows further upward out of the cutting chamber 2 via outlet 16 and preferably at least partially vertically arranged discharge pipe 18 in a three-phase flow (consisting of granule particles, water and air) for further processing, particularly the separation and drying of the granule 3.

[0031] Figure 1 and Figures 4 to 6 A water / particle discharge channel 17 for discharging a particle / water / gas mixture is shown, which is arranged on the upper part of the cutting chamber 2. The discharge channel is in the shape of a discharge pipe and is at least partially arranged to discharge the particle / water / gas mixture during operation.

[0032] Especially Figure 2 and Figure 3As shown, the device 1 has a frame 32, which is preferably movable by rollers, and a cutting device 12 is arranged on the frame, including a rotating blade and a drive mechanism 34 in the form of an electric motor, as well as a gear transmission mechanism connecting the drive mechanism 34 and the blade. The rotating blade is driven by a shaft 33, preferably horizontally arranged, in a manner known per se. Figure 4 and Figure 6 The drive shaft extends through the interior of the cutting chamber 2, where the cutting edge of the blade contacts the perforated disk and breaks the still-liquid outflowing melt into particles. These particles then form pellets 3 and solidify in water or other liquid within the cutting chamber 2. The shaft 33 for driving the blade is also located within the cutting chamber 2. Figure 6 As shown in the image.

[0033] like Figure 1 As shown in the embodiment, the cutting chamber 2 is installed within a piping system including a water supply pipe 38 and a water / particle discharge pipe 18, each connected to other pipes. A three-phase flow of water (or other liquid), particles 3, and gas (particularly air) is formed in the upper discharge pipe 18. Figure 1 and Figure 4 As shown, the three components of the three-phase flow flow in the directions indicated by arrows 39, 41, and 43.

[0034] In a manner not shown, the water connector 40 is connected to other pipes to supply water or other liquids from below, from the reservoir, and by means of a pump. Figures 2 to 4 The drain pipe 18 can also be seen at the top. Water or other liquids can be recycled.

[0035] like Figures 1 to 4As fully illustrated, a gas nozzle assembly 20 for introducing gas into water or other liquids through multiple nozzle orifices 44 is positioned inside a supply pipe 38 downstream of the (water) connector 40. Simultaneously, the gas nozzle assembly is arranged upstream of the outlet 6 of the cutting chamber 2, or directly inside or at the cutting chamber 2 (not shown), or, as shown in the embodiment, inside or at the water supply channel 36, preferably inside the water supply pipe 38. In the illustrated embodiment, the gas nozzle assembly 20 is preferably positioned at a section of the pipe 38 detachably connected to another section of the pipe 38. In one embodiment, the nozzle assembly 20 is correspondingly arranged inside the water supply channel 36 connected to the cutting chamber 2, allowing gas to flow in through gas inlet 19 and then into the cutting chamber 2 through inlet 14. According to this application, this method of introducing gas into the cutting chamber 2, or even directly introducing gas, results in the formation of a large number of gas bubbles, preferably, in the water-filled cutting chamber 2. The gas nozzle assembly 20 is arranged upstream of the water inlet 14 in the water supply area. It can also be seen from the figures that the gas nozzle assembly 20 is arranged below the template assembly 6. In this way, the formed bubbles 24 rise upward and reach the area of ​​melt particles discharged from the die assembly 6 into the cutting chamber 2, which form granules 3 and solidify in the water inside the cutting chamber 2 as the process continues.

[0036] from Figure 4 As can be seen, the melt outlet of the perforated disc of the template assembly is arranged such that the granular particles and the water / gas mixture move at least partially toward each other inside the cutting chamber 2, at an angle of approximately 60° to 120°, preferably approximately 90°. The channels inside the perforated disc are arranged generally horizontally, with the melt flowing into the cutting chamber 2 from right to left, while the (water / )gas mixture flows into the melting chamber 2 generally vertically upward through inlet 14; see also Figure 1 Arrows 39 and 41 in the diagram. During operation, air bubbles in the water interact with the particles of granule 3. The mass flow rate or volumetric flow rate of water, gas, and melt can be adjusted and changed accordingly by regulating the pump, gas supply, and water supply, and can be optimized to produce high-quality granule 3, especially compact granules.

[0037] like Figure 1 As shown, gas can be supplied to the gas nozzle assembly 20 via a preferably horizontally arranged conduit 29. The conduit 29 is connected to a compressed gas source in a manner not shown. It extends through an opening in the wall of the supply pipe 38. The orifice 44 of the gas nozzle assembly 20, in an embodiment arranged inside the supply pipe, or alternatively directly inside the cutting chamber 2, is used to release gas from the nozzle assembly 20 into water or other liquid, and ultimately into the cutting chamber 2; see also Figures 8 to 12 Hole 44 can be arranged in a ring, a straight line, or any random pattern. Figure 6 and Figure 10 This illustrates how the nozzle assembly 20 is designed as an annular nozzle with multiple holes 44 located on the circumference.

[0038] Figure 6 The cross-sectional view shows the supply pipe 38, in which a gas nozzle assembly 20 is arranged with an annular nozzle designed with multiple orifices 44. Gas, along with water, enters the interior of the cutting chamber 2 through inlet 14. Particles 3, produced using the nozzle assembly 6 and cutting device 12, are also supplied to the cutting chamber, where they come into contact with water and gas (particularly bubbles 24). The mixture of particles 3, water, and gas flows out of the cutting chamber 2 through outlet 16 and pipe 18.

[0039] Figure 7 and Figure 8 The gas nozzle assembly 20 and the conduit 29 (line 29) for supplying gas / air from a compressed gas source to the nozzle assembly 20 are shown. Gas is supplied through the conduit 29 to the interior of a section of the supply pipe 38.

[0040] Figure 9 and Figure 10 The gas nozzle assembly 20 is shown to be designed as an annular nozzle with multiple orifices 44, which allows a large number of bubbles to be formed in the water flow.

[0041] Figure 11 and Figure 12 An alternative embodiment of the nozzle assembly 20 is shown. Here, a plurality of holes with orifices 44 are formed in the wall of a section of the (water) supply pipe 38, through which gas can be supplied to the interior of the supply pipe 38. For this purpose, pipe 29 is connected to an annular space 46. Figure 12 Gas can flow from the annular space 46 through the orifice 44 into the interior of the supply pipe 38.

[0042] The accompanying drawings also illustrate an underwater granulation method according to the present disclosure for producing granules 3 from flowable, curable plastics, preferably performed using a granulation apparatus 1. Liquid plastic is supplied in melt form to a template assembly 6 having a template and discharged from the template in the form of multiple melt streams through multiple flow channels within the template. A large number of individual microparticles forming granules are produced at the template by a cutting device 12 having at least one rotating blade. The granule microparticles are discharged into a cutting chamber 2 (water tank) filled with water or other liquid. Water or other liquid is supplied to the cutting chamber 2 through at least one (water) inlet 14. Gas is introduced into the cutting chamber 2 directly or indirectly through a supply channel 36 via a gas inlet 19. The gas supplied to the cutting chamber 2 interacts with the granule particles inside the water- or liquid-filled cutting chamber 2. The water or other liquid, along with the granules 3 and gas, is discharged from the cutting chamber 2 through at least one outlet 17. The gas is preferably supplied through the gas inlet 19 to a gas nozzle assembly 20 connected to the gas inlet and having multiple nozzle orifices 44. The gas flowing from the nozzle orifice 44 forms a large number of bubbles 24 inside or before the cutting chamber 2 in the (water) supply channel 36 connected to the cutting chamber 2. According to an embodiment, gas is introduced into the (water) supply channel 36 by the gas nozzle assembly 20, which is preferably generally vertically oriented and preferably arranged generally below the template assembly 6, and supplies the (water / ) gas mixture to the cutting chamber 2 during operation.

[0043] Preferably, the gas (preferably compressed air) is continuously supplied according to this disclosure. Here, continuous gas supply should be understood as the gas volumetric flow rate or mass flow rate being constant, where the flow rate can vary, i.e., different volumetric flow rates or mass flow rates can be set. However, alternatively, in the method according to this disclosure, using the apparatus according to this application, the gas can also be supplied at a variable volumetric flow rate or mass flow rate. For example, according to this application, the gas can also be supplied intermittently, i.e., the gas supply is turned on at a specific stage and paused at another stage. It is reasonable for those skilled in the art to implement continuous or variable, discontinuous, intermittent gas supply. For example, the gas supply can be changed by opening or closing appropriate valves, and / or by changing appropriate throttle valves, or by adjusting different volumetric flow rates or mass flow rates. Those skilled in the art will understand that the gas, particularly air, can be provided from a gas source such as a compressed gas system. The gas supply can be controlled and regulated by appropriate control devices.

[0044] Figure 13 shows a schematic image of plastic pellets 3 produced according to the prior art. Figure 14 The diagram illustrates plastic pellets 3 produced under similar production conditions using the apparatus 1 according to this application, according to the production method of this application. Figure 13 and... Figure 14Different results are shown; Figure 13 shows the inflation method not using this application. Figure 14 The inflation method described in this application is adopted.

[0045] In this experiment, the following parameters were set: Experimental setup as follows Figure 1 As shown in the example; the mass flow rate of the plastic melt: 150 kg / h; the temperature of the process water: 60°C.

[0046] The shapes of the small particles are highly irregular (Figure 13): Figure 13 shows that the particles produced according to the prior art are elongated and, in some cases, far from being compact, ideal spheres. The ratio of the minimum to the maximum length of the particles deviates significantly from the value of 1. This ratio is 1 for an ideal sphere.

[0047] Using the inflation method described in this application: mass flow rate of plastic melt: 150 kg / h, process water temperature: 60℃, and 10% compressed air inflation, the shape of the small particles is significantly improved in terms of compactness and roundness, and is closer to a spherical shape. Figure 14 ).from Figure 14 A comparison of the particle shape in (according to this application) with that in Figure 13 (according to the prior art) shows that, due to the inflation method of this application, the particles are significantly closer to a sphere and significantly more compact. The ratio of minimum width to maximum length is closer to the ideal spherical ratio of 1.

[0048] Figure 15 shows a schematic image of plastic pellets 3 produced according to the prior art. Figure 16 The invention illustrates plastic pellets produced under similar production conditions using the apparatus 1 according to the present disclosure, according to the production method of this application.

[0049] Figure 15 and Figure 16 Different results are shown; Figure 15 shows the inflation method not using this application. Figure 16 The inflation method described in this application is used. In this experiment, the following parameters were set: the experimental setup is as follows... Figure 1 As shown in the example; the mass flow rate of the plastic melt: 200 kg / h; the temperature of the process water: 50°C, resulting in very irregular shapes of the small particles (Figure 15).

[0050] The inflation method used in this application is as follows: mass flow rate of plastic melt: 200 kg / h, process water temperature: 50℃, inflation with 50% compressed air, and minimal change in the shape of the small particles. Figure 16 However, it is clear that the smaller particles are more rounded and closer to spherical in shape.

[0051] Measurement results show that the air-filling method disclosed herein improves the roundness of pellet 3. Figure 16Here, roundness is improved from 0.661 to 0.765, where the value 1.0 represents spherical roundness. Roundness is determined here by calculating the ratio of the minimum to the maximum length of the particle.

[0052] The surface area of ​​individual particles has also decreased, indicating a positive shift towards a more spherical shape.

[0053] Figures 13 and 15 (Prior Art) and Figure 14 and Figure 16 A comparison of this application shows that aerating the process water according to this application affects the shape of the granules formed during the curing process. According to this application, during the curing of the granules, the interaction of air bubbles in the process water in the cutting chamber 2 region leads to an improvement in the quality of the granules 3, making the granules denser and closer to spherical than in the prior art.

[0054] Reference number list 1. Underwater granulation device 2. Cutting chamber (water tank) 3. Granules or particles (microparticles) 6 Template Components 7 Templates 8 Melt Inlet 10 Melt outlet 12 Cutting equipment 14 (Water) Inlet 16 (Water / ) Granular material outlet 17 (Water / ) Granular material discharge channel 18 (Water / ) Granular material discharge pipe 19 Gas Inlet 20 Gas Nozzle Assembly 24 bubbles 29 Pipelines 31 Transmission Gear 32 racks 33 drive shaft 34. Drive mechanism (cutting equipment) 35 blades 36 (Water) Supply Channel 38 (Water) Supply Pipe 39 Arrows indicating the direction of water flow 40 (Water) Connector 41 Arrows indicating the direction of airflow 43 Arrows indicating the direction of pellet flow 44 Nozzle orifice 46. ​​Circular Space One embodiment: An underwater granulation apparatus includes: a template assembly having a melt inlet for supplying liquid melt and a melt outlet for discharging multiple melt strips into an adjacent cutting chamber. The underwater granulation apparatus further includes cutting equipment for producing granules from the melt strips. The underwater granulation apparatus also includes a cutting chamber adjacent to the template assembly, which can be filled with water or other liquid, the cutting chamber having at least one (water) inlet for supplying water or other liquid into the cutting chamber, and at least one (water) granule outlet for discharging a mixture of water or other liquid and granules from the cutting chamber. The underwater granulation apparatus is characterized by further including at least one gas inlet connectable to a gas source for directly or indirectly supplying gas into the cutting chamber, such that the supplied gas can interact with the granules inside the cutting chamber.

[0055] The above embodiments may further include any combination of one or more of the following embodiments: The granulation apparatus of the above embodiments is characterized by having a gas nozzle assembly connectable to a gas inlet, the gas nozzle assembly having a plurality of nozzle orifices for directly or indirectly discharging gas into a cutting chamber, wherein the gas nozzle assembly is directly arranged inside the cutting chamber or inside a (water) supply channel connected to the cutting chamber, enabling the formation of a large number of bubbles in a cutting chamber that can be filled with water or other liquids. The granulation apparatus of the above embodiments is characterized by having the gas nozzle assembly arranged upstream of the outlet of the cutting chamber, preferably directly inside or at the cutting chamber, or indirectly inside or at the (water) supply channel, preferably inside the (water) supply pipe. The granulation apparatus of the above embodiments is characterized by having the gas nozzle assembly arranged below the template assembly. The granulation apparatus of the above embodiments is characterized by having the gas nozzle assembly arranged inside a water supply pipe forming a water supply channel, the water supply pipe preferably being generally vertically oriented and preferably generally arranged below the template assembly, and supplying a water / gas mixture to the cutting chamber during operation.

[0056] One embodiment: An underwater granulation apparatus includes: a template assembly having a melt inlet for supplying liquid melt and a melt outlet for discharging multiple melt strips into an adjacent cutting chamber; the underwater granulation apparatus further includes cutting equipment for producing granular particles from the melt strips. The underwater granulation apparatus also includes a cutting chamber adjacent to the template assembly, which can be filled with water or other liquid, the cutting chamber having at least one inlet for supplying water or other liquid into the cutting chamber, and at least one granule outlet for discharging a mixture of water or other liquid and granules from the cutting chamber. The underwater granulation apparatus also includes at least one gas inlet connectable to a gas source for supplying gas directly or indirectly into the cutting chamber, such that the supplied gas can interact with the granules inside the cutting chamber.

[0057] The above embodiments may further include any combination of one or more of the following embodiments: A granulation apparatus of the above embodiments, wherein a gas nozzle assembly connectable to a gas inlet is provided, the gas nozzle assembly having a plurality of nozzle orifices for directly or indirectly discharging gas into a cutting chamber, and the gas nozzle assembly is directly arranged inside the cutting chamber or inside a supply channel connected to the cutting chamber, enabling the formation of a large number of bubbles in a cutting chamber that can be filled with water or other liquids. A granulation apparatus of the above embodiments, wherein the gas nozzle assembly is arranged upstream of the outlet of the cutting chamber. A granulation apparatus of the above embodiments, wherein the gas nozzle assembly is directly arranged inside or at the cutting chamber, or indirectly arranged inside or at the supply channel, and located upstream of the outlet of the cutting chamber. A granulation apparatus of the above embodiments, wherein the gas nozzle assembly is directly arranged inside or at the cutting chamber, or indirectly arranged inside or at the supply channel inside the supply pipe, and located upstream of the outlet of the cutting chamber. A granulation apparatus of the above embodiments, wherein the gas nozzle assembly is arranged below the template assembly. In the granulation apparatus of the above embodiments, the gas nozzle assembly is arranged inside a water supply pipe forming a water supply channel. This water supply pipe is preferably oriented substantially vertically and is preferably arranged substantially below the template assembly, supplying a water / gas mixture to the cutting chamber during operation. In the granulation apparatus of the above embodiments, the melt outlet of the template assembly is arranged such that the granular particles and the water / gas mixture move at least partially toward each other within the cutting chamber at an angle generally between 60° and 120°, preferably about 90°. In the granulation apparatus of the above embodiments, the gas nozzle assembly is in the form of annular nozzles. In the granulation apparatus of the above embodiments, a water / granule discharge channel for discharging the granule mixture and / or water mixture is arranged in the upper part of the cutting chamber. This discharge channel is preferably tubular and at least partially substantially vertically arranged to discharge the granule mixture, water mixture, and / or gas mixture during operation. The underwater granulation method of the above embodiments preferably uses the granulation apparatus, wherein: liquid plastic is supplied in the form of melt to a template assembly having a template, and discharged from the template in the form of multiple melt strips through multiple flow channels in the template; the discharged melt strips are divided into individual granular particles by a cutting device; the granular particles are discharged into a cutting chamber filled with water or other liquid; water or other liquid is introduced into the cutting chamber through at least one inlet; and water or other liquid and granules are transported out of the cutting chamber through at least one outlet; wherein gas is introduced into the cutting chamber through a gas inlet, such that the gas interacts with the granular particles inside the cutting chamber filled with water or other liquid.In the underwater granulation method of the above embodiments, gas is supplied through a gas inlet to a gas nozzle assembly connected to the gas inlet and having a plurality of nozzle orifices; and the gas is discharged from the nozzle orifices into a cutting chamber to form a large number of bubbles inside the cutting chamber or inside a supply channel connected to the cutting chamber, and the bubbles interact with the granule particles in the cutting chamber, thereby affecting the shape of the granules or particles during solidification. In the underwater granulation method of the above embodiments, gas is introduced through a nozzle assembly located downstream of an inlet in the water supply area, wherein the gas nozzle assembly is preferably arranged below the template assembly. This is according to at least one of the foregoing embodiments.

[0058] It should be understood that although the terms "first," "second," etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0059] It should be understood that when an element, such as a layer, region, or substrate, is referred to as being "on" or "extending" to another element, it can be directly on or directly extending to the other element, or intermediate elements may exist. Conversely, when an element is referred to as being "directly on" or "directly extending" to another element, no intermediate elements exist. Similarly, it should be understood that when an element, such as a layer, region, or substrate, is referred to as being "above" or "extending" to another element, it can be directly above or directly extending to the other element, or intermediate elements may exist. Conversely, when an element is referred to as being "directly above" or "directly extending" to the other element, no intermediate elements exist. It should also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intermediate elements may exist. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, no intermediate elements exist.

[0060] In this document, relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used to describe the relationship between one element, layer, or region and another element, layer, or region, as shown in the figures. It should be understood that these terms, as well as the terms discussed above, are intended to cover different orientations of the device other than those shown in the figures.

[0061] The terminology used herein is for descriptive purposes only and is not intended to limit this application. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well. It should also be understood that when the terms “comprising,” “including,” “containing,” and / or “comprising” are used herein, they indicate the presence of the said feature, integer, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0062] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms used herein shall be interpreted as having the same meaning as they have in this specification and the relevant field, and shall not be interpreted as having an idealized or overly formal meaning, unless expressly defined herein.

[0063] Many features and advantages of this disclosure are apparent from the detailed description, and therefore the appended claims are intended to cover all such features and advantages that fall within the true spirit and scope of this application. Furthermore, since many modifications and variations will readily conceive of those skilled in the art, it is not intended to limit this application to the exact construction and operation shown and described; therefore, all suitable modifications and equivalents may be invoked, and they fall within the scope of this disclosure.

Claims

1. An underwater pelletizing apparatus for producing pellets from free-flowing, curable plastics, comprising: The template assembly has a melt inlet for supplying molten metal and a melt outlet for discharging multiple melt strips into adjacent cutting chambers. Cutting equipment used to produce granular materials from molten stock; as well as A cutting chamber, adjacent to the template assembly and capable of being filled with water or other liquid, the cutting chamber having at least one (water) inlet to supply water or other liquid into the cutting chamber, and at least one (water) pellet outlet to discharge a mixture of water or other liquid and pellets from the cutting chamber; The underwater granulation device is characterized in that it further includes at least one gas inlet that can be connected to a gas source for directly or indirectly supplying gas to the cutting chamber, so that the supplied gas can interact with the granules inside the cutting chamber.

2. The granulation apparatus according to claim 1, Its features are, A gas nozzle assembly is provided that can be connected to the gas inlet. This gas nozzle assembly has multiple nozzle orifices for directly or indirectly discharging gas into the cutting chamber. The gas nozzle assembly is disposed directly inside the cutting chamber or inside the (water) supply channel connected to the cutting chamber, thereby enabling the formation of a large number of bubbles in the cutting chamber, which can be filled with water or other liquids.

3. The granulation apparatus according to claim 2, characterized in that, The gas nozzle assembly is arranged upstream of the outlet of the cutting chamber, preferably directly inside or at the cutting chamber, or indirectly inside or at the (water) supply channel, preferably inside the (water) supply pipe.

4. The granulation apparatus according to claim 2 or 3, characterized in that, The gas nozzle assembly is arranged below the template assembly.

5. The granulation apparatus according to at least one of claims 2 to 4, characterized in that, The gas nozzle assembly is arranged inside a water supply pipe that forms a water supply channel. The water supply pipe is preferably oriented generally vertically and is preferably arranged generally below the template assembly, and supplies a water / gas mixture to the cutting chamber during operation.

6. The granulation apparatus according to at least one of the preceding claims, characterized in that, The melt outlet of the template assembly is arranged such that the granular particles and the water / gas mixture move at least partially toward each other inside the cutting chamber at an angle of approximately 60° to 120°, preferably at an angle of about 90°.

7. The granulation apparatus according to at least one of the preceding claims, characterized in that, A water / granule discharge channel for discharging the granule ( / water) mixture is arranged in the upper part of the cutting chamber. The discharge channel is preferably tubular and at least partially arranged substantially vertically to discharge the granule / water / gas mixture during operation.

8. The granulation apparatus according to at least one of the preceding claims, characterized in that, The gas nozzle assembly is in the form of an annular nozzle.

9. An underwater granulation method for producing granules from flowable, curable plastics, preferably using a granulation apparatus according to at least one of the preceding claims, wherein: Liquid plastic is supplied in the form of melt to a template assembly with a template, and discharged from the template in the form of multiple melt strips through multiple flow channels in the template; The discharged molten material is divided into individual granular particles by a cutting device; The granular material is discharged into a cutting chamber filled with water or other liquids; Water or other liquids are introduced into the cutting chamber through at least one (water) inlet; and Water or other liquids and granules are conveyed out of the cutting chamber through at least one outlet; Its characteristic feature is that gas is introduced into the cutting chamber through a gas inlet, so that the gas interacts with the granular particles inside the cutting chamber which is filled with water or other liquids.

10. The method according to claim 9, in, Gas is supplied through a gas inlet to a gas nozzle assembly connected to the gas inlet and having multiple nozzle orifices; and Gas is discharged from the nozzle orifice into the cutting chamber to form a large number of bubbles inside the cutting chamber or inside the (water) supply channel connected to the cutting chamber, and the bubbles interact with the granular particles in the cutting chamber, thereby affecting the shape of the granules or particles as they solidify.

11. The method according to at least one of the preceding claims, characterized in that, Gas is introduced through a nozzle assembly located in the water supply area downstream of the (water) inlet, wherein the gas nozzle assembly is preferably arranged below the template assembly.

12. The method according to at least one of the preceding claims, characterized in that, Gas is introduced into a water supply pipe that forms a water supply channel via a gas nozzle assembly. The water supply pipe is preferably oriented generally vertically and is preferably arranged generally below the template assembly, and supplies a water / gas mixture to the cutting chamber during operation.

13. An underwater pelletizing apparatus for producing pellets from flowable, curable plastics, comprising: A template assembly having a melt inlet for supplying liquid melt and a melt outlet for discharging multiple melt strips into an adjacent cutting chamber; Cutting equipment used to produce granular materials from molten stock; as well as A cutting chamber, adjacent to the template assembly and capable of being filled with water or other liquid, the cutting chamber having at least one inlet for supplying water or other liquid into the cutting chamber, and having at least one pellet outlet for discharging a mixture of water or other liquid and pellets from the cutting chamber; The underwater granulation device further includes at least one gas inlet that can be connected to a gas source, for supplying gas directly or indirectly to the cutting chamber, so that the supplied gas can interact with the granules inside the cutting chamber.

14. The granulation apparatus according to claim 13, in, A gas nozzle assembly is provided that can be connected to a gas inlet. This gas nozzle assembly has multiple nozzle orifices for directly or indirectly discharging gas into the cutting chamber; and The gas nozzle assembly is disposed directly inside the cutting chamber or inside the supply channel connected to the cutting chamber, enabling the formation of a large number of bubbles in the cutting chamber, which can be filled with water or other liquids.

15. The granulation apparatus according to claim 14, wherein, The gas nozzle assembly is positioned upstream of the outlet of the cutting chamber.

16. The granulation apparatus according to claim 14, wherein, The gas nozzle assembly is arranged upstream of the outlet of the cutting chamber, directly inside or at the cutting chamber, or indirectly inside or at the supply channel.

17. The granulation apparatus according to claim 14, wherein, The gas nozzle assembly is arranged upstream of the outlet of the cutting chamber, directly inside or at the cutting chamber, or indirectly inside or at the supply channel inside the supply pipe.

18. The granulation apparatus according to claim 14, wherein, The gas nozzle assembly is arranged below the template assembly.

19. The granulation apparatus according to at least one of claims 14, wherein, The gas nozzle assembly is arranged inside the water supply pipe that forms the water supply channel.

20. The granulation apparatus according to at least one of claims 14, wherein, The gas nozzle assembly is arranged inside a water supply pipe that forms a water supply channel, and the water supply pipe is oriented generally vertically.

21. The granulation apparatus according to at least one of claims 14, wherein, The gas nozzle assembly is arranged inside a water supply pipe that forms a water supply channel. The water supply pipe is generally vertically oriented and located generally below the template assembly, and supplies a water / gas mixture to the cutting chamber during operation.

22. The granulation apparatus according to claim 19, wherein, The melt outlet of the template assembly is arranged such that the granular particles and the water / gas mixture move at least partially toward each other inside the cutting chamber at an angle of approximately 60° to 120°.

23. The granulation apparatus according to claim 19, wherein, The melt outlet of the template assembly is arranged such that the granular particles and the water / gas mixture move at least partially toward each other inside the cutting chamber at an angle of approximately 90°.

24. The granulation apparatus according to claim 13, wherein, Water / granular discharge channels for discharging granular mixtures and / or water mixtures are arranged in the upper part of the cutting chamber.

25. The granulation apparatus according to claim 13, wherein, A water / granule discharge channel for discharging the granular mixture and / or water mixture is arranged in the upper part of the cutting chamber, and the discharge channel is tubular.

26. The granulation apparatus according to claim 13, wherein, A water / granular discharge channel for discharging a mixture of granules and / or a mixture of water is arranged in the upper part of the cutting chamber. The discharge channel is tubular and at least partially arranged to be generally vertical so as to discharge the mixture of granules, water and / or gas mixtures during operation.

27. The granulation apparatus according to claim 14, wherein, The gas nozzle assembly is in the form of an annular nozzle.

28. An underwater granulation method for producing granules from flowable, curable plastics, using the granulation apparatus according to claim 13, wherein: Liquid plastic is supplied in the form of melt to a template assembly with a template, and discharged from the template in the form of multiple melt strips through multiple flow channels in the template; The discharged molten material is divided into individual granular particles by a cutting device; The granular material is discharged into a cutting chamber filled with water or other liquids; Water or other liquids are introduced into the cutting chamber through at least one inlet; and Water or other liquids and granules are conveyed out of the cutting chamber through at least one outlet; In this process, gas is introduced into the cutting chamber through a gas inlet, allowing the gas to interact with the granular particles inside the cutting chamber, which is filled with water or other liquids.

29. The underwater granulation method according to claim 28, in, Gas is supplied through a gas inlet to a gas nozzle assembly connected to the gas inlet and having multiple nozzle orifices; and Gas is discharged from the nozzle orifice into the cutting chamber to form a large number of bubbles inside the cutting chamber or inside the supply channel connected to the cutting chamber. The bubbles interact with the granules in the cutting chamber, thereby affecting the shape of the granules or particles as they solidify.

30. The underwater granulation method according to claim 28, wherein, Gas is introduced through a nozzle assembly located in the water supply area downstream of the inlet.

31. The underwater granulation method according to claim 28, wherein, Gas is introduced through a nozzle assembly located in the water supply area downstream of the inlet, wherein the gas nozzle assembly is arranged below the template assembly.

32. The underwater granulation method according to claim 28, wherein, Gas is introduced into the supply pipe that forms the supply channel through a gas nozzle assembly.

33. The underwater granulation method according to claim 28, wherein, Gas is introduced into a supply pipe that forms a supply channel via a gas nozzle assembly; the supply pipe is oriented approximately vertically.

34. The underwater granulation method according to claim 28, wherein, Gas is introduced into a supply pipe that forms a supply channel via a gas nozzle assembly. This supply pipe is generally vertically oriented and positioned approximately below the template assembly, and supplies a water / gas mixture to the cutting chamber during operation.

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