EP2239051A1 - Processing device for bulk material - Google Patents

Abstract

The device (10) has a conveying pipe (17) for supplying bulk material to a mixing and conveying station. A vacuum-generating system (24) has a vacuum hose (23). An air supply is connected to the station for conveying and/or mixing the material. A screen (21) separates the material from air, and has screen openings matched to a desired level of separation for separating the material from the air. Air from the air supply flows into the material and effects mixing of the material and removal of dust from the material, where air has a temperature of 40 degrees Celsius to 200 degrees Celsius.

Description

Technical area

The invention relates to a processing device for bulk material.

State of the art

From the DE 40 29 902 a device and a method for conveying and mixing of bulk material are known. For this purpose, a downwardly tapered container is provided with a bottom closure plate, wherein a suction conveyor fan arranged outside the container generates a negative pressure in the container. About a conveyor pipe system to be conveyed bulk material is supplied. In the prior art, at least two delivery pipes are provided within the delivery pipe system, each having a delivery valve. With the above device, a thorough mixing of the bulk material can be made. Other functions do not meet this conveyor.

It is also from the DE OS 20 26 337 a method for mixing a powdery ground substance with similar additives known. In this method, the basic substance is first conveyed in the suction air flow through a feed nozzle into the container. After the settled layer in the container has reached a certain height in order to effect a sufficient throttling, a shut-off device is opened, and it starts the suction of the dispensed by the dosing device in the hopper additives. The carrier air laden with the additives emerges from the mouth and rises through the substance layers above it in a fine distribution upwards, wherein it gradually releases the additives to the ground substance. A mixing or turbulence of the substances with each other does not take place.

It is still out of the DE 25 44 716 A1 a suction conveyor with a pneumatic mixer known. The components are conveyed and weighed separately and are stacked on top of each other after completion of a delivery cycle. After complete supply of the components, a pneumatic mixing of the components is carried out via a corresponding venting valve. This requires several process steps, which run sequentially, so that a relatively long delivery and mixing time is needed.

The invention has for its object to avoid the disadvantages mentioned and to provide a processing facility for bulk material, which is characterized by a simple structure and on the one hand ensures a reliable mixing of the bulk material, on the other hand, the bulk processed so that optimal processing in a subsequent processing machine is guaranteed.

Disclosure of the invention

The essential advantage of the invention is that not only a thorough mixing of the bulk material takes place, but at the same time a dedusting of the bulk material is achieved. For this purpose, a sieve in the area provided the air extraction, the corresponding openings, so that possibly contained in the mix dust escaped through these openings and can be sucked off, so that there is an additional function dedusting. The supply of hot air improves the dedusting quality.

The material to be processed, d. H. The mix is either sucked directly from containers and fed to the mixing and conveying or fed from granulators or shredders of the mixing and conveying. By mixing the material and extracting the air, the material is whirled up and mixed. At the same time unwanted fines from the material mixture dissolve and can be sucked off. The degree of dedusting is determined using different screens that can be used in the mixing and conveying station.

Another significant advantage of the invention is that the various operations, such as conveying, dosing, mixing and dedusting, are carried out cost-effectively in one device. As a result, injection molding and extrusion processes are less time-consuming, as the material is processed in parallel and very clean material is used. Due to the homogeneous mixing ratio of different material components inferior parts or even rejects are reduced and the product quality increased. Nester formation due to dust or fines is effectively prevented.

Another important advantage is that the existing filter systems do not clog up and that there are fewer fines in the material to be conveyed, thus ensuring a homogeneous working process.

Advantageously, this method is used in the mixing of plastic granules and feeding of plastic granules in a plastic injection molding machine.

According to development, a valve is provided on a delivery pipe. This valve allows air to be mixed and dedusted, allowing for time and volume control.

According to an alternative, a supply air pipe for supplying air for mixing and dedusting is provided at the conveyor station. This supply air pipe is equipped with a valve, with which the mixing time, d. H. the time for supplying air and at the same time the amount of air supplied, is adjustable.

According to training, the mixing and conveying station is provided with a bottom closure flap. About this, the mix is derived and fed, for example, a plastic injection molding machine or more generally a processing station.

An embodiment of the invention provides to provide a further delivery pipe for conveying a further component of the bulk material. Thus, two different products of the mixing and conveying device can be supplied in parallel or successively. For example, a plastic granulate in the form of virgin material can be fed through a conveying pipe, and a plastic grinding material can be fed through a further conveying pipe. Especially with regrind is the dust content is relatively high, so that the dedusting significantly improves the quality of the ground material and the quality of the entire bulk material.

The mixing and conveying device is arranged downstream of a vacuum generating system. This consists of a suction fan and a receptacle for the discharged dust. Between the suction fan and the receptacle, a filter in the form of a filter element or a cyclone separator is provided. At this point, the dust is separated from the conveying air. Also, the dust collector has a bottom closure flap to dispose of or divert the dust collected therein.

The mixing and conveying device according to a further advantageous embodiment of the invention as a compact unit directly or indirectly on processing machines, such. As injection molding machines, blow molding or other plastic processing machines, put on. There is also the possibility of the device with which the dedusting of plastic granules is used as an independent unit or as an additional dedusting system in the plastic conveying and plastics processing.

These and other features are evident not only from the claims, but also from the description and the drawings.

Brief description of the drawings

The invention will be explained below with reference to exemplary embodiments.

FIG. 1 shows a multifunction device for conveying, mixing and dedusting of plastic granulate.

FIG. 2 shows a schematic representation of the supply of hot air.

Embodiment (s) of the invention

According to the figure, a mixing and conveying device 10 is provided, consisting of a container 11, which is provided with a bottom closure flap 12, and an outlet 13, which is arranged below the bottom closure flap. The outlet 13 is connected to a plastics processing unit 14, for example a metering screw for a plastic injection molding. Between the plastic processing unit 14 and the outlet 13, a dosing device 40, which is schematically indicated here, can optionally be provided for dosing in additional material. The container 11 has openings 15, 16, on each of which a delivery pipe 17, 18 is located. The delivery pipes 17, 18 extend down to a respective container 19, 20, in which plastic granulate is located. This plastic granulate can be virgin or regrind. Above the openings 15, 16 of the container 11, a sieve 21 is provided. Above the sieve a suction chamber 22 is arranged, which is in communication with a vacuum hose 23. The vacuum hose 23 leads to a negative pressure generating system 24, which consists of a dust separator 25 and a vacuum blower 26.

The dust collector 25 is constructed in the manner of a conventional vacuum cleaner, d. H. it has a dust collecting container 27 which is provided with a closure flap 28 for discharging the accumulated dust. In the upper part of the dust collector 25 is equipped with a filter cartridge 29, which separates the dust collection chamber or raw air from the clean air chamber 30. The clean air space is provided with a clean air line 31. This leads to the vacuum blower 26, which ultimately ensures that the bulk material in the containers 19, 20 is supplied to the container 11 and on the other hand, the dust-containing air is purified. On the container 11 is also an external air supply 32, consisting of a projecting into the bulk material tube 33 and the tube 33, which extends through the container 11 to the outside, final valve 34th

• Nach dem Einschalten des Unterdruckgebläses 26 wird aus dem Behälter 19 oder 20 oder gleichzeitig aus beiden Behältern je nach Stellung des Verschlussventils 35, 36 Kunststoffgranulat oder Mahlgut in die Misch- und Fördereinrichtung 10 transportiert. Das Mahlgut setzt sich auf der Bodenverschlussklappe auf und füllt diesen Behälter bis zu einer bestimmten maximalen Füllhöhe. Zum Durchmischen und Entstauben wird - gleichzeitig oder nachdem die Ventile 35, 36 geschlossen sind - das Ventil 34 geöffnet, so dass Fremdluft einströmt und für eine Durchmischung und gleichzeitig eine Entstaubung des im Behälter befindlichen Schüttgutes 37 sorgt. Damit kein Schüttgut in den Unterdruckschlauch 23 bzw. in die Absaugkammer 22 gelangen kann, ist ein Sieb 21 vorgeschaltet. Dieses Sieb hat eine Maschenweite, die einerseits das Austragen von Staub in die Absaugkammer 22 zulässt, andererseits das Austragen von Schüttgut ab einer bestimmten Korngröße unterbindet. Hierzu besteht die Möglichkeit, das Sieb mit unterschiedlichen Maschenweiten auszustatten bzw. unterschiedliche Siebe in die Misch- und Fördereinrichtung einzusetzen. Nachdem eine ausreichende Durchmischung des Schüttgutes stattgefunden hat und gleichzeitig dieses entstaubt ist, wird das Ventil 34 geschlossen. Durch Öffnen der Bodenverschlussklappe 12 kann das Schüttgut der Kunststoffverarbeitungseinheit 14 zugeleitet werden. Der von der Misch- und Fördereinrichtung 10 abgesaugte Staub gelangt zu dem Staubabscheider 25, wird dort im Staubsammelbehälter 27 gesammelt und kann über die Verschlussklappe 28 nach unten zu einem Staubbehälter 38 geführt werden. Der Staub wird durch eine Filterpatrone 29, wie bei einem Staubsauger üblich, zurückgehalten. Die Filterpatrone sorgt dafür, dass dem Unterdruckgebläse 26 nur Reinluft zugeführt wird, die anschließend in die Atmosphäre entlassen werden kann. An dem Staubabscheider 25 ist ein Ausgleichsfilter 39 zum Druckausgleich vorgesehen. Beim Entstauben des Schüttgutes 27 lässt sich durch ein mehr oder weniger starkes Öffnen des Ventils 34 die zugeführte Luftmenge steuern, d. h. es erfolgt eine intensivere oder weniger intensive Durchwirbelung des Schüttgutes, je nach Art des im Behälter 11 befindlichen Materials.

The operation of the multifunction device is described below:

• After switching on the vacuum blower 26, 36 plastic granules or ground material is transported from the container 19 or 20 or simultaneously from both containers depending on the position of the closure valve 35, 36 in the mixing and conveying device. The material sits on the bottom flap and fills this container up to a certain maximum level. For mixing and dedusting - the valve 34 is opened at the same time or after the valves 35, 36 are closed so that external air flows in and ensures thorough mixing and dedusting of the bulk material 37 in the container. So that no bulk material can get into the vacuum hose 23 or into the suction chamber 22, a wire 21 is connected upstream. This sieve has a mesh size, on the one hand allows the discharge of dust into the suction chamber 22, on the other hand prevents the discharge of bulk material from a certain grain size. For this purpose, it is possible to equip the screen with different mesh sizes or to use different screens in the mixing and conveying. After sufficient mixing of the bulk material has taken place and at the same time this dedusted, the valve 34 is closed. By opening the bottom closure flap 12, the bulk material can be supplied to the plastics processing unit 14. The extracted from the mixing and conveying device 10 dust passes to the dust collector 25, where it is collected in the dust collector 27 and can be guided over the flap 28 down to a dust container 38. The dust is retained by a filter cartridge 29, as is common in a vacuum cleaner. The filter cartridge ensures that the vacuum blower 26 only clean air is supplied, which can then be discharged into the atmosphere. At the dust separator 25, a compensation filter 39 is provided for pressure equalization. When dedusting the bulk material 27 can be controlled by a more or less strong opening of the valve 34, the amount of air supplied, ie there is a more intense or less intense turbulence of the bulk material, depending on the type of material contained in the container 11.

FIG. 2 shows a filing with a supply of hot air. This device has a container 53 which is provided with a material inlet 41 and has a sieve 42 in the upper region. At the geodetically lower end of the container 53 is provided with an outlet valve 43, for example, this is a pneumatic slide 44. On the left side, a hot air supply 45 is disposed on the container 53. This feed has a heater 46. Furthermore, an air supply valve 47 is arranged on the hot air supply 45 to additionally introduce supply air. In the upper area of the container 53 is provided with an exhaust duct 54. At this exhaust duct 54 is a temperature measuring device 48 for measuring the exhaust air temperature. The exhaust air line 54 leads on the left side via a valve 49 to an air exhaust 50. The air flowing there can Be led to the outside via a dust collector, not shown here. On the right side, a valve 51 is provided. If this is open and the valve 49 is closed, the extracted air is fed to a central filter system 52. This central filter system is in FIG. 1 also shown on the right side of the mixing device and well known. By the inflow of air through the hot air supply 45, the bulk material in the container 53 is swirled. At the same time, the hot air ensures a dedusting of the bulk material or at a higher temperature for a crystallization of the swirled in the container bulk material.

The advantage of the hot air during dedusting is that different moist material that is in the container, is easy and quick to dedust, that is, the dedusting time is shortened and the dedusting effect is qualitatively better.

Claims (3)

Processing device for bulk material, in particular for conveying and mixing the same, comprising a mixing and conveying station, at least one conveying pipe for supplying the bulk material to be conveyed, wherein the mixing and conveying station is connected to a vacuum hose or tube and the vacuum hose or tube to a Vacuum generating system is arranged, wherein air is supplied for conveying and / or mixing and within the mixing and conveying station for separating the conveyed material from the air is a sieve whose sieve openings correspond to the desired degree of separation for the separation of the mixed material from the air and Air flows into the mix and causes a mixing of the mix and a dedusting of the mix and wherein the air has a temperature of 40 ° C - 200 ° C. Machining device according to claim 1, characterized in that for dedusting the mixed material, the air has a temperature of 40 ° C - 80 ° C and / or for crystallizing the mixture has a temperature of 120 ° C - 200 ° C. Machining device according to claim 1 or 2, wherein the temperature of the air is heated by a heating system with an electric heater.

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