EP0487829B1 - Apparatus for drying bulk material - Google Patents

Apparatus for drying bulk material Download PDF

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Publication number
EP0487829B1
EP0487829B1 EP91113077A EP91113077A EP0487829B1 EP 0487829 B1 EP0487829 B1 EP 0487829B1 EP 91113077 A EP91113077 A EP 91113077A EP 91113077 A EP91113077 A EP 91113077A EP 0487829 B1 EP0487829 B1 EP 0487829B1
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EP
European Patent Office
Prior art keywords
bulk material
temperature
container
air
bulk
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EP91113077A
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German (de)
French (fr)
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EP0487829A1 (en
Inventor
Dieter Karls
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Mann and Hummel GmbH
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Filterwerk Mann and Hummel GmbH
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/06Controlling, e.g. regulating, parameters of gas supply
    • F26B21/12Velocity of flow; Quantity of flow, e.g. by varying fan speed, by modifying cross flow area
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/12Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft
    • F26B17/14Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft the materials moving through a counter-current of gas
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/001Handling, e.g. loading or unloading arrangements
    • F26B25/002Handling, e.g. loading or unloading arrangements for bulk goods

Definitions

  • the invention relates to a device for drying bulk material in an essentially cylindrical bulk container according to the preamble of claim 1.
  • DE-OS 20 52 334 It is also known from DE-OS 20 52 334 a method and an apparatus for drying bulk material, the bulk material being dehumidified with heated dry gas, in particular air, in a container. To adequately dehumidify a large amount of bulk material, it is proposed to additionally heat the container. However, this requires a further air circuit and a heating device to be arranged therein, this further air circuit being switched on when the outlet temperature of the exhaust air falls below a certain temperature value.
  • the bulk goods dried in the container are removed virtually continuously and new bulk goods are fed in from above in accordance with the amount removed.
  • the heated air introduced can also be adapted to this bulk material throughput.
  • the bulk material throughput is increased to such an extent that the drying is no longer guaranteed by the maximum available air introduced, then there is a risk that bulk material with too high a moisture content leaves the drying container and that it is no longer possible to process this bulk material in a quality-appropriate manner.
  • a solution to this problem cannot be found in the known prior art.
  • a device for drying bulk goods in an essentially cylindrical bulk goods container is known.
  • a temperature measuring device is arranged which detects the temperature in the bulk material.
  • the temperature measuring device immediately sends a control signal to a hydraulic motor, which serves to discharge the dried bulk material, in this case the dried grain.
  • This direct coupling between the sensor and the motor has the disadvantage that external interference cannot be optimally corrected with this system. Is z. B. already dried grain or almost dry grain is fed, with undiminished addition of drying air under certain circumstances overheating the grain.
  • a device is also known from GB-A 2 202 318 in which an inadmissible operating state, if the temperature in the bulk material reaches a certain limit temperature, is indicated by a signal device which emits a signal. No further processing of this signal is provided.
  • This object is achieved on the basis of the preamble of the main claim by its characterizing features.
  • the invention makes use of the knowledge that there is a temperature gradient within the bulk material located in the essentially cylindrical container. This temperature gradient is based on the maximum temperature of the heated dry air supplied and ends at the temperature of the newly filled bulk material. If a lot of bulk material is now removed, this temperature gradient shifts in the direction of the bulk material outlet. If little or no bulk material is removed, this temperature gradient shifts in the direction of the bulk material inlet.
  • a temperature sensor detects the temperature of the bulk material in the area of this temperature gradient. If the temperature at the measuring point now drops, this is an indication that very much bulk material is removed. As soon as the measured temperature falls below a certain permissible limit, this means that the bulk solids are too high. Different reactions can now be triggered. On the one hand, there is the possibility of emitting an optical or acoustic signal which indicates that the bulk material removal is too high, so that the bulk material removal can be throttled. There is also the option of interrupting bulk material removal or to throttle via a switching element controlled by the temperature sensor. The temperature sensor can of course also detect the rise in temperature within the bulk material. This rise in temperature indicates that so little bulk material is removed that the amount of heated dry air supplied is too large in relation to the bulk material removal. Because of this relationship, the amount of air supplied is now reduced when an upper temperature limit is reached, so that energy-saving drying of the bulk material is associated with this.
  • a device for drying bulk goods consists, as shown in FIG. 1, of a bulk goods container 10, which has a filler neck 25 and a bulk goods removal 23.
  • This bulk material removal is provided, for example, with a closing device 13.
  • the bulk material is transported further via a conveying line 14 with pneumatic conveying.
  • the bulk material is dried in an air drying device 11.
  • an air drying device 11 Such a device is generally known and is described, for example, in DE-PS 31 31 471.
  • the air drying device 11 has a control panel 22 for controlling the device.
  • the drying air circulates in a closed air circuit and is moved by a fan which is arranged in the air drying device 11. If several bulk material containers are connected to a single air drying device, the supply air line 12 contains a branch for each bulk material container.
  • a branch 18 is provided for the bulk goods container 10.
  • a shutoff valve 16 is located on this branch. When the shutoff valve is open, the drying air flows into an injection pipe 24, which is shown schematically here and through which a uniform introduction of the heated, dry air into the bulk material 15 is ensured.
  • the inflow of air rises upwards through the bulk material 15, heats it up, at the same time absorbs the moisture present in the bulk material, leaves the bulk material container via the air outlet 19 and is in turn fed to the air drying device 11 via the exhaust air line 20.
  • the conveying line 14 is connected to one or more plastic processing machines, for example injection molding machines.
  • the operating cycle of these injection molding machines is normally constant, so that there is a quasi-continuous removal of the plastic granulate and a uniform feeding of the same into the bulk material container.
  • the amount of dry air supplied to the bulk material container is adapted to the maximum throughput of the plastic granulate.
  • FIG. 4 shows the temperature curve theta / degree C of the bulk material in the bulk material container above the maximum filling level.
  • Curve A shows the temperature curve that occurs when the plastic granulate is removed evenly at a medium removal rate. It can be seen that in the lower half of the container the temperature of the plastic granulate is approximately constant and corresponds to the temperature of the heated air supplied, in this case 80 degrees C.
  • the temperature of the bulk material decreases continuously in the upper area of the container and reaches the temperature at the upper edge of the bulk material cone that the bulk material is at Filling in the container usually has. This temperature is around 20 degrees.
  • h0 denotes the height of the outlet of the container
  • h max means the top edge of the bulk material cone.
  • a temperature sensor is located at a position of the bulk goods container, which is denoted by h t in FIG.
  • This temperature sensor 21 measures the bulk material temperature of the bulk material surrounding it. This essentially corresponds to the temperature at which the air that passes the temperature sensor is at. This temperature is shown in Figure 4 with the designation t1.
  • the temperature sensor 21 is connected to a signal converter 17.
  • This signal converter converts the measured temperature into an analog digital electrical signal.
  • This signal arrives at a warning device 26, which consists, for example, of an acoustic and an optical signal transmitter.
  • a temperature curve B will occur.
  • This temperature curve B shows that the dwell time of the removed bulk material in the bulk material container is too short to ensure adequate drying.
  • the bulk material is heated to the temperature of 80 degrees at short notice. This short time is not enough to achieve complete drying of the bulk material.
  • the temperature sensor detects a drop in temperature up to the temperature point t2. This temperature point is below a limit temperature which is such that above this limit temperature t g sufficient drying of the bulk material is still ensured.
  • a warning signal is emitted via the warning device 26 below this limit temperature. This warning signal shows that the granulate removal must be interrupted until this limit temperature t g is exceeded again.
  • the warning signal of the warning device 26 can, through the optical and / or acoustic effect, cause an operator to initiate a measure that reduces the consumption of plastic granulate.
  • the signal converter 17 can also be connected directly to a control device 27 for the closing device 13. With this type of connection of the temperature sensor 21 with the closing device 13, monitoring by an operator is superfluous.
  • the delivery to bulk goods is controlled independently depending on whether the limit temperature t g is exceeded or not reached. That is, as soon as the temperature falls below the limit, the control device 27 causes the flow of bulk material to be interrupted via the closing device 13.
  • the temperature sensor can also take on the task of temperature monitoring, as described by FIGS. 1 or 2.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Fertilizers (AREA)

Abstract

The essentially cylindrical bulk-material container (10) has an air inlet with a blow-in pipe (24) for introducing heated dry air into bulk material (15) situated in the container. At a lower end which tapers in a funnel-shaped manner, the container has a bulk-material removal device (23) with, connected thereto, a conveying line (14), via which the bulk material is guided to a corresponding further processing machine. The bulk material is supplied to the container via a funnel-shaped filling piece (25). In the cylindrical region of the container, a temperature-measuring device (21) is arranged, which detects the temperature of the bulk material. As soon as this temperature falls below a given limit value (tg), either a warning signal is given by a warning device (26) or the removal of the bulk material is interrupted or reduced by actuating a closure device (13). <IMAGE>

Description

Die Erfindung betrifft eine Vorrichtung zum Trocknen von Schüttgut in einem im wesentlichen zylinderförmigen Schüttgutbehälter nach dem Oberbegriff Anspruchs 1.The invention relates to a device for drying bulk material in an essentially cylindrical bulk container according to the preamble of claim 1.

Eine derartige Vorrichtung ist aus des US-A-4 004 351 bekannt.Such a device is known from US-A-4 004 351.

Aus der EP-A 00 95 265 ist eine Einrichtung zum Steuern des Trockungsvorgangs von Schüttgut bekannt, bei dem die eingeleitete erwärmte Luft bezüglich ihrer Temperatur und ihres Feuchtegehalts sowie die abgeleitete Abluft ebenfalls bezüglich ihrer Temperatur und ihres Feuchtegehaltes erfaßt wird. Innerhalb des Schüttguts ist ferner ein Temperaturfühler und ein Feuchtigkeitsfühler angebracht, welche die Meßdaten über den Zustand des Schüttgutes liefern. Sämtliche Meßwerte gelangen zu einer Auswerteeinrichtung, die in Abhängigkeit von den gemessenen Werten den Trockungsvorgang steuern.From EP-A 00 95 265 a device for controlling the drying process of bulk material is known, in which the introduced heated air with respect to its temperature and its moisture content and the discharged exhaust air is also recorded with regard to its temperature and its moisture content. A temperature sensor and a moisture sensor are also mounted inside the bulk material and provide the measurement data about the condition of the bulk material. All measured values are sent to an evaluation device which controls the drying process as a function of the measured values.

Die Kombination von Temperatur- und Feuchtesensor ist sehr aufwendig. Außerdem ist bekannt, daß die üblicherweise verwendeten Feuchtigkeitssensoren eine hohe Meßungenauigkeit aufweisen. Insbesondere, wenn es sich bei dem Schüttgut um zu trocknendes Kunststoffgranulat handelt, ist diese Art der Trocknungssteuerung zu ungenau, da es sich bei der Kunststofftrocknung um die Entfernung einer sehr geringen Restfeuchte handelt, deren Erfassung meßtechnisch sehr schwierig ist.The combination of temperature and humidity sensors is very complex. It is also known that the moisture sensors commonly used have a high measurement inaccuracy. This type of drying control is too imprecise, in particular if the bulk material is plastic granules to be dried, since it is the case with Plastic drying is the removal of a very low residual moisture, which is very difficult to measure.

Es ist weiterhin aus der DE-OS 20 52 334 ein Verfahren und eine Vorrichtung zum Trocknen von Schüttgut bekannt, wobei in einem Behälter das Schüttgut mit erwärmtem Trockengas, insbesondere Luft, entfeuchtet wird. Zur ausreichenden Entfeuchtung einer großen Schüttgutmenge wird vorgeschlagen, zusätzlich Wärme dem Behälter zuzuführen. Dies erfordert jedoch einen weiteren Luftkreislauf sowie eine darin anzuordnende Heizeinrichtung, wobei dieser weitere Luftkreislauf dann eingeschaltet wird, wenn die Austrittstemperatur der Abluft einen bestimmten Temperaturwert unterschreitet.It is also known from DE-OS 20 52 334 a method and an apparatus for drying bulk material, the bulk material being dehumidified with heated dry gas, in particular air, in a container. To adequately dehumidify a large amount of bulk material, it is proposed to additionally heat the container. However, this requires a further air circuit and a heating device to be arranged therein, this further air circuit being switched on when the outlet temperature of the exhaust air falls below a certain temperature value.

Normalerweise wird das in dem Behälter getrocknete Schüttgut quasi kontinuierlich entnommen und neues Schüttgut entsprechend der entnommenen Menge von oben zugeführt. So lange die entnommene Schüttgutmenge annähernd gleichbleibend ist, kann auch die eingeleitete erwärmte Luft diesem Schüttgutdurchsatz angepaßt werden. Wird der Schüttgutdurchsatz jedoch soweit erhöht, daß die Trocknung durch die eingeleitete maximal zur Verfügung stehende Luft keine ausreichende Trocknung mehr gewährleistet, dann besteht die Gefahr, daß Schüttgut mit einem zu hohen Feuchtigkeitsgehalt den Trocknungsbehälter verläßt und eine qualitätsgerechte Weiterverarbeitung dieses Schüttguts nicht mehr möglich ist. Eine Lösung diese Problems ist dem bekannten Stand der Technik nicht zu entnehmen.Normally, the bulk goods dried in the container are removed virtually continuously and new bulk goods are fed in from above in accordance with the amount removed. As long as the quantity of bulk material withdrawn is approximately constant, the heated air introduced can also be adapted to this bulk material throughput. However, if the bulk material throughput is increased to such an extent that the drying is no longer guaranteed by the maximum available air introduced, then there is a risk that bulk material with too high a moisture content leaves the drying container and that it is no longer possible to process this bulk material in a quality-appropriate manner. A solution to this problem cannot be found in the known prior art.

Aus der US 4 004 351 ist eine Vorrichtung zum Trocknen von Schüttgut in einem im wesentlichen zylinderförmigen Schüttgutbehälter bekannt. Im zylinderförmigen Bereich des Behälters ist eine Temperaturmeßeinrichtung angeordnet, die die Temperatur in dem Schüttgut erfaßt. Die Temperaturmeßeinrichtung gibt unmittelbar ein Stellsignal an einen hydraulischen Motor, welcher um Austrag des getrockneten Schüttguts, in diesem Fall des getrockneten Korns, dient. Diese unmittelbare Kopplung zwischen Sensor und Motor hat den Nachteil, daß äußere Störeinflüsse mit diesem System nicht optimal korrigiert werden können. Wird z. B. bereits getrocknetes Korn oder nahezu trockenes Korn zugeführt, so erfolgt bei unverminderter Zugabe von Trocknungsluft unter Umständen eine überhitzung des Korns.From US 4 004 351 a device for drying bulk goods in an essentially cylindrical bulk goods container is known. In the cylindrical area of the container, a temperature measuring device is arranged which detects the temperature in the bulk material. The temperature measuring device immediately sends a control signal to a hydraulic motor, which serves to discharge the dried bulk material, in this case the dried grain. This direct coupling between the sensor and the motor has the disadvantage that external interference cannot be optimally corrected with this system. Is z. B. already dried grain or almost dry grain is fed, with undiminished addition of drying air under certain circumstances overheating the grain.

Es ist weiterhin aus der GB-A 2 202 318 eine Einrichtung bekannt, bei der ein unzulässiger Betriebszustand, falls die Temperatur in dem Schüttgut eine bestimmte Grenztemperatur erreicht, durch eine Signaleinrichtung, die ein Signal abgibt, angezeigt wird. Eine Weiterverarbeitung dieses Signals ist nicht vorgesehen.A device is also known from GB-A 2 202 318 in which an inadmissible operating state, if the temperature in the bulk material reaches a certain limit temperature, is indicated by a signal device which emits a signal. No further processing of this signal is provided.

Es ist Aufgabe der Erfindung, in Abhängigkeit von dem entnommenen Schüttgut die Einleitung erwärmter, trockener Luft derart zu steuern, daß eine konstante Trocknung des Schüttgutes gewährleistet und eine Energieeinsparung erzielt wird. Diese Aufgabe wird ausgehend von dem Oberbegriff des Hauptanspruchs durch dessen kennzeichnenden Merkmale gelöst.It is an object of the invention to control the introduction of heated, dry air as a function of the bulk material removed in such a way that constant drying of the bulk material is ensured and energy savings are achieved. This object is achieved on the basis of the preamble of the main claim by its characterizing features.

Die Erfindung macht sich die Erkenntnis zunutze, daß innerhalb des in dem im wesentlichen zylinderförmigen Behälter befindlichen Schüttgutes ein Temperaturgefälle vorhanden ist. Dieses Temperaturgefälle geht von der Maximaltemperatur der zugeführten erwärmten trockenen Luft aus und endet bei der Temperatur des neu eingefüllten Schüttguts. Wird nun sehr viel Schüttgut entnommen, dann verschiebt sich dieses Temperaturgefälle in Richtung des Schüttgutauslasses. Wird wenig oder kein Schüttgut entnommen, verschiebt sich dieses Temperaturgefälle in Richtung des Schüttguteinlasses.The invention makes use of the knowledge that there is a temperature gradient within the bulk material located in the essentially cylindrical container. This temperature gradient is based on the maximum temperature of the heated dry air supplied and ends at the temperature of the newly filled bulk material. If a lot of bulk material is now removed, this temperature gradient shifts in the direction of the bulk material outlet. If little or no bulk material is removed, this temperature gradient shifts in the direction of the bulk material inlet.

Ein Temperatursensor erfaßt im Bereich dieses Termperaturgefälles die Temperatur des Schüttgutes. Fällt nun die Temperatur an dem Meßort ab, ist dies ein Anzeichen, daß sehr viel Schüttgut entnommen wird. Sobald die gemessene Temperatur unter einen bestimmten zulässigen Grenzwert fällt, bedeutet dies, daß die Schüttgutentnahme zu hoch ist. Es können nun unterschiedliche Reaktionen ausgelöst werden. Zum einen besteht die Möglichkeit, ein optisches oder akustisches Signal abzugeben, welches auf die zu hohe Schüttgutentnahme hinweist, so daß die Schüttgutentnahme gedrosselt werden kann. Es besteht auch die Möglichkeit, die Schüttgutentnahme zu unterbrechen oder über ein mit dem Temperatursensor gesteuertes Schaltglied zu drosseln. Der Temperatursensor kann natürlich auch das Ansteigen der Temperatur innerhalb des Schüttgutes erfassen. Dieses Ansteigen der Temperatur deutet darauf hin, daß so wenig Schüttgut entnommen wird, daß die Menge der zugeführten erwärmten trockenen Luft in Bezug auf die Schüttgutentnahme zu groß ist. Aufgrund dieses Zusammenhangs wird nun bei Erreichen eines oberen Temperaturgrenzwertes die zugeführte Luftmenge reduziert, so daß damit ein energiesparendes Trocknen des Schüttgutes verbunden ist.A temperature sensor detects the temperature of the bulk material in the area of this temperature gradient. If the temperature at the measuring point now drops, this is an indication that very much bulk material is removed. As soon as the measured temperature falls below a certain permissible limit, this means that the bulk solids are too high. Different reactions can now be triggered. On the one hand, there is the possibility of emitting an optical or acoustic signal which indicates that the bulk material removal is too high, so that the bulk material removal can be throttled. There is also the option of interrupting bulk material removal or to throttle via a switching element controlled by the temperature sensor. The temperature sensor can of course also detect the rise in temperature within the bulk material. This rise in temperature indicates that so little bulk material is removed that the amount of heated dry air supplied is too large in relation to the bulk material removal. Because of this relationship, the amount of air supplied is now reduced when an upper temperature limit is reached, so that energy-saving drying of the bulk material is associated with this.

Es ist unerheblich, wo die genaue Position des Temperaturfühlers innerhalb des Schüttgutes liegt. Wesentlich ist nur, daß der Temperaturfühler nicht zu weit in den Bereich des Lufteinlasses hineinreicht, da dort das Granulat die Temperatur der erwärmten Luft sehr rasch annimmt. Außerdem wäre dieser Meßort zu nahe an dem Schüttgutauslaß. Bei einer hohen Schüttgutentnahme könnte dies dazu führen, daß das Schüttgut zwar schon die entsprechende Temperatur erreicht hat, aber die Verweilzeit innerhalb dieser Temperatur noch nicht ausreichend war, um das Schüttgut zu trocknen.It is irrelevant where the exact position of the temperature sensor is within the bulk material. It is only important that the temperature sensor does not extend too far into the area of the air inlet, since there the granulate very quickly assumes the temperature of the heated air. In addition, this location would be too close to the bulk material outlet. With a high bulk solids removal, this could lead to the fact that the bulk material has already reached the corresponding temperature, but the dwell time within this temperature was not yet sufficient to dry the bulk material.

Die Erfindung wird nachfolgend anhand eines Ausführungsbeispiels näher erläutert. Es zeigt:

Figur 1
einen Schüttgutbehälter mit einer Warneinrichtung,
Figur 2
einen Schüttgutbehälter mit einer Klappensteuerung,
Figur 3
einen Schüttgutbehälter mit einer Wärmemengensteuerung,
Figur 4
ein Diagramm des Temperaturverlaufs im Schüttgutbehälter.
The invention is explained in more detail below using an exemplary embodiment. It shows:
Figure 1
a bulk container with a warning device,
Figure 2
a bulk container with a flap control,
Figure 3
a bulk container with a heat quantity control,
Figure 4
a diagram of the temperature profile in the bulk container.

Eine Vorrichtung zum Trocknen von Schüttgut besteht, wie in Figur 1 dargestellt ist, aus einem Schüttgutbehälter 10, welcher einen Einfüllstutzen 25 und eine Schüttgutentnahme 23 aufweist. Diese Schüttgutentnahme ist beispielsweise mit einer Verschließvorrichung 13 versehen. Der Weitertransport des Schüttguts über eine Förderleitung 14 erfolgt mit einer pneumatischen Förderung.A device for drying bulk goods consists, as shown in FIG. 1, of a bulk goods container 10, which has a filler neck 25 and a bulk goods removal 23. This bulk material removal is provided, for example, with a closing device 13. The bulk material is transported further via a conveying line 14 with pneumatic conveying.

Sofern das Schüttgut 15 in den Behälter kontinuierlich über den Einfüllstutzen 25 nachgefüllt wird, bildet sich im oberen Bereich des Behälters ein Schüttgutkegel aus, so daß die Füllhöhe immer konstant ist.If the bulk material 15 is continuously refilled into the container via the filler neck 25, a bulk material cone is formed in the upper region of the container, so that the filling level is always constant.

Die Trocknung des Schüttgutes erfolgt in einer Lufttrocknungseinrichtung 11. Eine solche ist allgemein bekannt und beispielsweise in der DE-PS 31 31 471 beschrieben. Die Lufttrocknungseinrichtung 11 weist ein Bedienfeld 22 zur Steuerung der Einrichtung auf. Die Trocknungsluft zirkuliert in einem geschlossenen Luftkreislauf und wird durch ein Gebläse, welches in der Lufttrocknungseinrichtung 11 angeordnet ist, bewegt. Die Zuluftleitung 12 enthält, sofern mehrere Schüttgutbehälter mit einer einzigen Lufttrocknungseinrichtung verbunden sind, für jeden Schüttgutbehälter einen Abzweig. Für den Schüttgutbehälter 10 ist ein Abzweig 18 vorgesehen. An diesem Abzweig befindet sich ein Absperrventil 16. Die Trockungsluft strömt bei geöffnetem Absperrventil in ein Einblasrohr 24, welches hier schematisch dargestellt ist und durch welches eine gleichmäßige Einleitung der erwärmten trocknene Luft in das Schüttgut 15 gewährleistet ist.The bulk material is dried in an air drying device 11. Such a device is generally known and is described, for example, in DE-PS 31 31 471. The air drying device 11 has a control panel 22 for controlling the device. The drying air circulates in a closed air circuit and is moved by a fan which is arranged in the air drying device 11. If several bulk material containers are connected to a single air drying device, the supply air line 12 contains a branch for each bulk material container. A branch 18 is provided for the bulk goods container 10. A shutoff valve 16 is located on this branch. When the shutoff valve is open, the drying air flows into an injection pipe 24, which is shown schematically here and through which a uniform introduction of the heated, dry air into the bulk material 15 is ensured.

Die eingeströmte Luft steigt nach oben durch das Schüttgut 15, erwärmt dieses, nimmt gleichzeitig die in dem Schüttgut vorhandene Feuchtigkeit auf, verläßt über den Luftauslaß 19 den Schüttgutbehälter und wird über die Abluftleitung 20 wiederum der Lufttrocknungseinrichtung 11 zugeführt.The inflow of air rises upwards through the bulk material 15, heats it up, at the same time absorbs the moisture present in the bulk material, leaves the bulk material container via the air outlet 19 and is in turn fed to the air drying device 11 via the exhaust air line 20.

Sofern es sich bei dem zu trocknenden Schüttgut um Kunststoffgranulat handelt, ist die Förderleitung 14 mit einer oder mehreren kunststoffverarbeitenden Maschinen, beispielsweise Spritzgießmaschinen verbunden. Der Arbeitstakt dieser Spritzgießmaschinen ist normalerweise konstant, so daß eine quasi kontinuierliche Abnahme des Kunststoffgranulats und eine gleichmäßige Zuführung desselben in den Schüttgutbehälter erfolgt. Die dem Schüttgutbehälter zugeführte trockene Luft ist bezüglich ihrer Menge an den maximalen Durchsatz des Kunststoffgranulats angepaßt.If the bulk material to be dried is plastic granulate, the conveying line 14 is connected to one or more plastic processing machines, for example injection molding machines. The operating cycle of these injection molding machines is normally constant, so that there is a quasi-continuous removal of the plastic granulate and a uniform feeding of the same into the bulk material container. The amount of dry air supplied to the bulk material container is adapted to the maximum throughput of the plastic granulate.

In der Praxis zeigt sich, daß nicht nur eine, sondern oft eine Vielzahl von Kunststoffverarbeitungsmaschinen an eine Vorrichtung zum Trocknen von Schüttgut angeschlossen sind. Dabei kann der Fall auftreten, daß die zugeführte Trockungsluft nicht mehr ausreicht, um einen solchen sehr hohen Schüttgutdurchsatz ausreichend zu trocknen. Eine ausreichende Trocknung wird nur dann erzielt, wenn das Schüttgut eine bestimmte vorgegebene Zeit mit trockener Luft beaufschlagt wurde, so daß auch die im Inneren jedes einzelnen Granulatkorns vorhandene Feuchtigkeit durch die Erwärmung von der vorbeiströmenden Luft aufgenommen wird.In practice, it can be seen that not only one but often a large number of plastic processing machines are connected to a device for drying bulk material. The case may arise that the supplied drying air is no longer sufficient to sufficiently dry such a very high bulk material throughput. Adequate drying is only achieved if dry air has been applied to the bulk material for a certain predetermined time, so that the moisture present in the interior of each individual granule is also absorbed by the air flowing past due to the heating.

Figur 4 zeigt den Temperaturverlauf Theta/Grad C des Schüttguts in dem Schüttgutbehälter über der maximalen Füllhöhe. Die Kurve A zeigt den Temperaturverlauf, der sich bei einer gleichmäßigen Entnahme des Kunststoffgranulats mit mittlerer Entnahmegeschwindigkeit einstellt. Dabei ist zu erkennen, daß in der unteren Hälfte des Behälters die Temperatur des Kunststoffgranulats annähernd konstant ist und der Temperatur der zugeführten erwärmten Luft, also in diesem Fall 80 Grad C, entspricht.FIG. 4 shows the temperature curve theta / degree C of the bulk material in the bulk material container above the maximum filling level. Curve A shows the temperature curve that occurs when the plastic granulate is removed evenly at a medium removal rate. It can be seen that in the lower half of the container the temperature of the plastic granulate is approximately constant and corresponds to the temperature of the heated air supplied, in this case 80 degrees C.

Im oberen Bereich des Behälters nimmt die Temperatur des Schüttgutes kontinuierlich ab und erreicht an der Oberkante des Schüttgutkegels die Temperatur, die das Schüttgut beim Einfüllen in den Behälter üblicherweise aufweist. Diese Temperatur liegt bei ca. 20 Grad. In diesem Diagramm ist mit h₀ die Höhe des Auslasses des Behälters bezeichnet, hmax bedeutet die Oberkante des Schüttgutkegels.The temperature of the bulk material decreases continuously in the upper area of the container and reaches the temperature at the upper edge of the bulk material cone that the bulk material is at Filling in the container usually has. This temperature is around 20 degrees. In this diagram, h₀ denotes the height of the outlet of the container, h max means the top edge of the bulk material cone.

Wie in Figur 1 dargestellt, befindet sich ein Temperatursensor an einer Position des Schüttgutbehälters, welche in Figur 4 mit ht bezeichnet ist. Dieser Temperatursensor 21 mißt die Schüttguttemperatur des ihn umgebenden Schüttgutes. Diese entspricht im wesentlichen auch der Temperatur, welche die Luft, die an dem Temperatursensor vorbeistreicht, aufweist. Diese Temperatur ist in Figur 4 mit der Bezeichnung t₁ dargestellt.As shown in FIG. 1, a temperature sensor is located at a position of the bulk goods container, which is denoted by h t in FIG. This temperature sensor 21 measures the bulk material temperature of the bulk material surrounding it. This essentially corresponds to the temperature at which the air that passes the temperature sensor is at. This temperature is shown in Figure 4 with the designation t₁.

Der Temperatursensor 21 ist an einen Signalumwandler 17 angeschlossen. Dieser Signalumwandler überträgt die gemessene Temperatur in ein analoges digitales elektrisches Signal. Dieses Signal gelangt zu einer Warneinrichtung 26, welche beispielsweise aus einem akustischen und einem optischen Signalgeber besteht.The temperature sensor 21 is connected to a signal converter 17. This signal converter converts the measured temperature into an analog digital electrical signal. This signal arrives at a warning device 26, which consists, for example, of an acoustic and an optical signal transmitter.

Wird eine sehr große Menge an Kunststoffgranulat entnommen, so daß eine ausreichende Trocknung nicht mehr gewährleistet ist, dann verschiebt sich das Temperaturgefälle innerhalb des Schüttgutbehälters nach unten, d. h., es wird sich, wie in Figur 4 gezeigt, ein Temperaturverlauf B einstellen. Dieser Temperaturverlauf B zeigt, daß die Verweildauer des entnommenen Schüttguts in dem Schüttgutbehälter zu kurz ist, um eine ausreichende Trocknung zu gewährleisten. Das Schüttgut wird allenfalls kurzfristig auf die Temperatur von 80 Grad erwärmt. Diese kurze Zeit reicht nicht aus, um eine vollständige Trocknung des Schüttgutes zu erzielen.If a very large amount of plastic granulate is removed so that adequate drying is no longer guaranteed, the temperature gradient within the bulk material container shifts downwards, i.e. that is, as shown in FIG. 4, a temperature curve B will occur. This temperature curve B shows that the dwell time of the removed bulk material in the bulk material container is too short to ensure adequate drying. The bulk material is heated to the temperature of 80 degrees at short notice. This short time is not enough to achieve complete drying of the bulk material.

Der Temperatursensor erfaßt ein Absinken der Temperatur bis zu dem Temperaturpunkt t₂. Dieser Temperaturpunkt liegt unter einer Grenztemperatur, die so bemessen ist, daß oberhalb dieser Grenztemperatur tg noch eine ausreichende Trocknung des Schüttguts gewährleistet ist. Unterhalb dieser Grenztemperatur wird ein Warnsignal über die Warneinrichtung 26 abgegeben. Dieses Warnsignal zeigt, daß die Granulatentnahme unterbrochen werden muß, bis diese Grenztemperatur tg wieder überschritten wird.The temperature sensor detects a drop in temperature up to the temperature point t₂. This temperature point is below a limit temperature which is such that above this limit temperature t g sufficient drying of the bulk material is still ensured. A warning signal is emitted via the warning device 26 below this limit temperature. This warning signal shows that the granulate removal must be interrupted until this limit temperature t g is exceeded again.

Das Warnsigal der Warneinrichtung 26 kann durch die optische und/oder akustische Wirkung eine Bedienperson veranlassen, eine Maßnahme einzuleiten, die den Verbrauch an Kunststoffgranulat reduziert. Anstelle einer Warneinrichtung 26 kann, wie in Figur 2 gezeigt, der Signalumwandler 17 auch unmittelbar an eine Steuereinrichtung 27 für die Verschließvorrichtung 13 angeschlossen werden. Bei dieser Art der Verknüpfung des Temperatursensors 21 mit der Verschließvorrichtung 13 wird eine Überwachung durch eine Bedienperson überflüssig. Hier erfolgt eine selbständige Steuerung der Abgabe an Schüttgut in Abhängigkeit von der über- bzw. Unterschreitung der Grenztemperatur tg. D. h., sobald die Grenztemperatur unterschritten ist, veranlaßt die Steuereinrichtung 27 ein Unterbrechen des Schüttgutstroms über die Verschließvorrichtung 13.The warning signal of the warning device 26 can, through the optical and / or acoustic effect, cause an operator to initiate a measure that reduces the consumption of plastic granulate. Instead of a warning device 26, as shown in FIG. 2, the signal converter 17 can also be connected directly to a control device 27 for the closing device 13. With this type of connection of the temperature sensor 21 with the closing device 13, monitoring by an operator is superfluous. Here, the delivery to bulk goods is controlled independently depending on whether the limit temperature t g is exceeded or not reached. That is, as soon as the temperature falls below the limit, the control device 27 causes the flow of bulk material to be interrupted via the closing device 13.

Selbstverständlich kann es auch vorkommen, daß der Schüttgutdurchsatz durch den Behälter verringert wird, beispielsweise, wenn eine oder mehrere Kunststoffverarbeitungsmaschinen abgeschaltet werden. Dies führt dann dazu, daß bei unverändertem Einströmen von trockener erwärmter Luft die Temperatur im Schüttgut ansteigt. Ein solcher Anstieg ist in Figur 4 durch den Verlauf der Kurve C dargestellt. Der Temperatursensor mißt dabei die Temperatur t₃. Über den Signalumwandler 17 wird bei Erreichen dieser Temperatur ein Stellsignal an das Absperrventil 16 gegeben. Dieses Absperrventil drosselt die Luftmenge und damit die zugeführte Wärmemenge, so daß ein weiteres Ansteigen der Temperatur in dem Behälter vermieden wird.Of course, it can also happen that the bulk material throughput through the container is reduced, for example when one or more plastics processing machines are switched off. This then leads to the fact that the temperature in the bulk material rises with the unchanged inflow of dry, heated air. Such an increase is shown in FIG. 4 by the course of curve C. The temperature sensor measures the temperature t₃. When this temperature is reached, a control signal is sent to the shut-off valve 16 via the signal converter 17. This shut-off valve throttles the amount of air and thus the amount of heat supplied, so that a further increase in Temperature in the container is avoided.

Selbstverständlich ist es möglich, die Steuerung des Absperrventils stufenlos durchzuführen, so daß schon bei einem geringfügigen Anstieg des Temperaturverlaufs in dem Behälter eine Drosselung der zugeführten Wärmemenge erfolgt. Gleichzeitig kann der Temperaturfühler auch die Aufgabe der Temperaturüberwachung, wie sie durch die Figuren 1 oder 2 beschrieben wurden, übernehmen.Of course, it is possible to carry out the control of the shut-off valve in a stepless manner, so that even with a slight increase in the temperature profile in the container, the amount of heat supplied is throttled. At the same time, the temperature sensor can also take on the task of temperature monitoring, as described by FIGS. 1 or 2.

Es besteht so mit der Anwendung eines einzigen Temperaturfühlers die Möglichkeit, sowohl eine - insbesondere für Kunststoffgranulat - ausreichende Trocknung des Kunststoffgranulats sicherzustellen als auch eine wesentliche Energieeinsparung bei ausreichender Trocknung zu erzielen.With the use of a single temperature sensor, it is possible both to ensure adequate drying of the plastic granulate, in particular for plastic granulate, and to achieve substantial energy savings with sufficient drying.

BezugszeichenlisteReference list

  • 10 Schüttgutbehälter10 bulk containers
  • 11 Lufttrocknungseinrichtung11 air drying device
  • 12 Zuluftleitung12 supply air line
  • 13 Verschließvorrichtung13 closing device
  • 14 Förderleitung14 delivery line
  • 15 Schüttgut15 bulk material
  • 16 Absperrventil16 shut-off valve
  • 17 Signalumwandler17 signal converter
  • 18 Abzweig18 branch
  • 19 Luftauslaß19 air outlet
  • 20 Abluftleitung20 exhaust duct
  • 21 Temperatursensor21 temperature sensor
  • 22 Bedienfeld22 Control panel
  • 23 Schüttgutentnahme23 Bulk material removal
  • 24 Einblasrohr24 injection pipe
  • 25 Einfüllstutzen25 filler neck
  • 26 Warneinrichtung26 Warning device
  • 27 Steuereinricntung27 Tax system

Claims (3)

  1. Apparatus for drying bulk material in a substantially cylindrical bulk material container (10), which is connected to an air drying means (11) and a heating means in a closed air circuit, wherein a fan is provided which conveys the dry heated air through the bulk material in order to remove moisture from the bulk material (15), and an air outlet duct (19, 20) extends from the container (10) to the air drying means (11), in which the used air from the bulk material container is dried again and freshly supplied to the bulk material container (10) via an air supply duct (12, 18, 24), a temperature measuring device (21) being disposed in the cylindrical portion of the bulk material container (10) and detecting the temperature of the bulk material (15), characterised in that the quantity of the air throughput flowing through the bulk material drier is controlled in dependence on this detected temperature via a shut-off valve (16) in such a manner that the air throughput is reduced as the bulk material temperature rises and increased as the bulk material temperature drops.
  2. Apparatus according to claim 1, characterised in that the removal of the bulk material is effected in a quasi-continuous manner, and the bulk material (15) is supplied in a quantity which corresponds to the quantity of bulk material removed.
  3. Apparatus according to one of the preceding claims, characterised in that the temperature measuring device (21) is situated in the region of the bulk material (15) in which, during the quasi-continuous removal of the bulk material, a temperature gradient is set, starting from the temperature of the drying air supplied and reaching up to the temperature of the bulk material (15) freshly supplied to the container.
EP91113077A 1990-11-24 1991-08-03 Apparatus for drying bulk material Expired - Lifetime EP0487829B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4037443A DE4037443A1 (en) 1990-11-24 1990-11-24 DEVICE FOR DRYING SCHUETTGUT
DE4037443 1990-11-24

Publications (2)

Publication Number Publication Date
EP0487829A1 EP0487829A1 (en) 1992-06-03
EP0487829B1 true EP0487829B1 (en) 1995-06-14

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ID=6418863

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Application Number Title Priority Date Filing Date
EP91113077A Expired - Lifetime EP0487829B1 (en) 1990-11-24 1991-08-03 Apparatus for drying bulk material

Country Status (8)

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US (1) US5182871A (en)
EP (1) EP0487829B1 (en)
AT (1) ATE123868T1 (en)
CA (1) CA2056154A1 (en)
CS (1) CS355191A3 (en)
DE (2) DE4037443A1 (en)
HU (1) HUT61094A (en)
PL (1) PL292496A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112240680A (en) * 2019-07-17 2021-01-19 株式会社松井制作所 Drying device for powder material and drying method for powder material

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK0669510T3 (en) * 1994-02-25 1999-08-16 Motan Holding Gmbh Drying machine
DE4434498C2 (en) * 1994-09-27 1996-12-12 Henkel Ecolab Gmbh & Co Ohg Process for cleaning dishes in commercial dishwashers and dishwasher suitable for carrying out the process
DE19848140C5 (en) * 1998-10-20 2008-10-02 Klaus Wilhelm Drying device for drying pourable material
DE19902327A1 (en) 1999-01-21 2000-07-27 Mann & Hummel Protec Gmbh Process for heating bulk goods, in particular plastic granules
DE19931357C1 (en) * 1999-07-07 2001-04-05 Colortronic Gmbh Method and device for drying granules
DE10238946A1 (en) 2002-08-24 2004-03-04 Mann + Hummel Protec Gmbh Conveying device for pourable goods
ITVR20030053A1 (en) * 2003-05-05 2004-11-06 Moretto Plastics Automation S R L MOLECULAR SIEVES EQUIPMENT AND DEHUMIDIFICATION SYSTEM
DE102004004680A1 (en) * 2004-01-29 2005-10-20 Mann & Hummel Protec Gmbh Automatic control of the drying of bulk material
US7343700B2 (en) 2005-01-28 2008-03-18 Mann & Hummel Protec Gmbh Automatic control of the drying of particulate material
DE102005062857A1 (en) * 2005-12-23 2007-06-28 Hauni Maschinenbau Ag Method and apparatus for drying a fiber product mass flow
US7856737B2 (en) * 2007-08-28 2010-12-28 Mathews Company Apparatus and method for reducing a moisture content of an agricultural product
US9950872B2 (en) 2015-11-30 2018-04-24 Superior Manufacturing LLC Bin sweep auger unplugging system
PL233328B1 (en) * 2017-09-13 2019-09-30 Univ Ekonomiczny We Wroclawiu Jet fan heating device

Family Cites Families (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2069193A (en) * 1936-06-20 1937-01-26 Yorktown Electric Roaster Mfg Automatic roaster
US2676095A (en) * 1948-01-14 1954-04-20 Erie Mining Co Indurating furnace and process
US2903800A (en) * 1955-07-05 1959-09-15 Svenska Flaektfabriken Ab Turbulent pneumatic driers for granular and pulverulent material
DE1451265B2 (en) * 1963-03-30 1970-02-05 Siemens AG, 1000 Berlin u. 8000 München Process for operating apparatuses, preferably heat exchangers, which work with movable mass particles as heat carriers, and a device for carrying out the process
US3563460A (en) * 1968-10-25 1971-02-16 Curtis Dyne Products Corp Grain bin aeration control
DE2052334A1 (en) * 1970-10-24 1972-04-27 Graeff R Granule drying - with primary and secondary heated air streams in the hopper
US3875683A (en) * 1974-05-17 1975-04-08 Whitlock Inc Integral heater plenum drying hoppers
US4004351A (en) * 1975-07-28 1977-01-25 Gilmore-Tatge Manufacturing Co., Inc. Grain drying apparatus
US4053991A (en) * 1976-04-13 1977-10-18 Steffen Sylvester L Automatic control for maintaining equilibrium temperature/moisture between stored grain and atmosphere
US4152840A (en) * 1977-08-31 1979-05-08 David Manufacturing Co. Grain dryer control system
DE3131471A1 (en) * 1981-03-20 1982-09-30 Roderich Wilhelm Dr.-Ing. 6100 Darmstadt Gräff DEVICE FOR DRYING HUMIDIFIER EXHAUST FROM ONE OR SEVERAL DUMP DRYING CONTAINERS
EP0095265A3 (en) * 1982-05-21 1984-11-14 Moisture Control &amp; Measurement Limited Control of drying operation
US4568417A (en) * 1982-09-16 1986-02-04 The Babcock & Wilcox Company Control system for prilling towers
SE450774B (en) * 1984-08-24 1987-07-27 Skf Steel Eng Ab SET FOR REFRIGERATING MATERIAL MATERIAL AND DEVICE FOR IMPLEMENTATION OF THE SET
US4688332A (en) * 1986-03-21 1987-08-25 Sentry Technologies, Inc. Method and apparatus for aeration of stored grain
FR2605851B1 (en) * 1986-11-05 1989-01-06 Secemia PROCESS AND PLANT FOR TREATING GRAIN FROM A DRYER, BY SLOW COOLING AND COMPLEMENTARY MOISTURE EXTRACTION
US4773168A (en) * 1986-12-24 1988-09-27 Aec, Inc. Thermal dryer for resin processing
DE3733793A1 (en) * 1987-10-06 1989-04-20 Graeff Roderich Wilhelm METHOD AND DEVICE FOR CRYSTALLIZING AMORPHIC PLASTIC GRANULES
DE3809749C1 (en) * 1988-03-23 1989-04-06 Filterwerk Mann & Hummel Gmbh, 7140 Ludwigsburg, De Appts. for drying heat sensitive bulk goods - has container holding goods through which hot air is re-circulated and a heater controlled by sensor in hot air outlet
DE8814825U1 (en) * 1988-11-29 1989-02-02 Becker, Markus, 3501 Habichtswald Continuous flow dryers, especially continuous flow dryers for grain
DE3929858A1 (en) * 1989-09-08 1991-03-21 Mann & Hummel Filter Drying loose, particulate materials in closed circuit - by passing warm air through material to remove moisture, drying and recirculating while air quantity is controlled to material output
DE8910763U1 (en) * 1989-09-09 1991-01-17 Filterwerk Mann & Hummel Gmbh, 7140 Ludwigsburg Device for drying bulk material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112240680A (en) * 2019-07-17 2021-01-19 株式会社松井制作所 Drying device for powder material and drying method for powder material
CN112240680B (en) * 2019-07-17 2022-06-07 株式会社松井制作所 Drying device for powder material and drying method for powder material

Also Published As

Publication number Publication date
DE59105712D1 (en) 1995-07-20
ATE123868T1 (en) 1995-06-15
CS355191A3 (en) 1992-06-17
EP0487829A1 (en) 1992-06-03
PL292496A1 (en) 1992-07-27
US5182871A (en) 1993-02-02
HU912630D0 (en) 1992-01-28
HUT61094A (en) 1992-11-30
CA2056154A1 (en) 1992-05-25
DE4037443A1 (en) 1992-05-27

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