PRODUCTION METHOD

Description

[0001] The invention relates to a method for producing cellulose-based excipients such as carboxymethylcellulose and the like.

Introduction

[0002] The specifications for cellulose based excipients, particularly pharmaceutical excipients, are high in order to comply with processing and regulatory requirements. Such cellulose products generally have a high value, however, there is a need to optimise the processing method to minimise losses and to provide a range of such cellulose-based products which meet these requirements.

Statements of Invention

[0003] According to the invention, there is provided a method for producing cellulose-based excipients comprising the steps of: -

setting a desired operating load on a grinder;

delivering coarse cellulosic material from a feed hopper to the grinder;

grinding the coarse cellulosic material;

classifying the ground cellulosic material in a classifier having a classifier drive unit;

controlling the classifier drive unit in accordance with the operating load on the grinder;

drawing the ground and classified cellulosic material into a grinder receiving bin;

delivering the ground and classified cellulosic material to a separator;

separating the classified cellulosic material into cellulosic material of a desired size and oversize material;

delivering the cellulosic material of desired size into a holding bin; and

packing the cellulosic material from the holding bin.

[0004] In one embodiment of the invention, the ground and classified material is drawn into the grinder receiving bin by a fan having a variable speed drive and the method includes the step, prior to delivery of the coarse cellulosic material to the grinder, of setting the speed of the fan drive to a desired speed matched to the coarse cellulosic material.

[0005] Preferably, the method includes the step of delivering the oversize cellulosic material from the separator to the feed hopper for recycling.

[0006] In one embodiment of the invention, the operating load on the grinder drive is sensed by sensing the operating power of the grinder drive, the classifier drive unit is a variable speed drive and the classifier drive unit is controlled by varying the drive speed of the classifier in accordance with the operating power of the grinder drive.

[0007] In a preferred arrangement, a rotary air valve is provided at the feed hopper outlet and the coarse cellulosic material is delivered from the feed hopper to the grinder by a blower unit.

[0008] Preferably, the method includes the step of de-bagging coarse cellulosic materials into the feed hopper.

Detailed Description of the Invention

[0009] The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawing which is a schematic diagram illustrating the method for producing cellulose-based pharmaceutical excipients according to the invention.

[0010] Referring to the drawing, there is illustrated a method for producing cellulose-based excipients and in this case pharmaceutical excipients such as carboxymethylcellulose and the like. The method is in this case used in the production of three different types of cellulose-based excipients. These may be a blend of different excipients. Equivalent equipment used in processing different cellulosic materials are illustrated in some cases for clarity as separate items but are assigned the same reference numerals.

[0011] In the method of the invention, coarse cellulosic material is delivered into a feed hopper 1 having an outlet fitted in this case with a fixed speed rotary valve 2. The coarse cellulosic material is blown by a blower unit 3 along a common supply line 4 to a grinder/classifier unit 5. The grinder/classifier unit 5 comprises a grinder 10 and a classifier 11. The grinder 10 has a drive unit with an associated power load, in this case, operating amps monitor 12 fitted with a controller 13. The classifier 11 is driven by a variable speed drive unit 15, the operation of which is controlled by the controller 13.

[0012] A fan 20 fitted with a variable speed drive unit 21 draws ground and classified cellulosic material along a delivery line 22 to a grinder receiving bin 23. Air is exhausted through a plurality of air filter socks 25. The receiving bin 23 has an outlet fitted with a rotary valve 27 through which the ground and classified cellulosic material is delivered to a separator screen unit 30. The screen unit 30 may have any size of aperture fitted to achieve separation into a desired size fraction and oversize. The desired size fraction is delivered through a rotary valve 31 by a blower unit 32 along an output line 35. The oversize material is recovered and delivered along a recycling line 38 to the feed hopper 1. In some cases, the cellulosic material with the desired size distribution is delivered into a silo 40 and collected in a holding bin 41 available for packaging on demand. In another case, the cellulosic material is blended for improved consistency in a blender unit 45 fitted with a blending screw prior to delivery to a silo 40.

[0013] In the method of the invention, cellulose-based excipients are produced by first setting, using the variable speed drive unit 21, an operating speed for the fan 20 matched to the cellulosic material being processed. A desired operating load on the grinder 10 is then set using the amp sensing unit 12 linked to the controller 13 for controlling the speed control unit 15 of the classifier 11. The fan 20 and blower unit 3 are operated to release the valve 2, allowing coarse cellulosic material to be delivered along the feed line 4 to the grinder 10. The coarse cellulosic material is ground in the grinder 10 and then classified in the classifier 11. The drive unit 15 of the classifier 11 is controlled in accordance with the operating load on the grinder 10. The fan 20 draws the ground and classified cellulosic material into the grinder receiving bin 23. On operation of the rotary valve 27, the cellulosic material is delivered to the separator unit 30 where the cellulosic material is separated into cellulosic material of a desired size and oversize material which is recycled to the feed hopper 1.

[0014] The invention provides an optimised process for producing not only one but several different cellulose-based excipients, particularly pharmaceutical excipients. The particle size range of the cellulosic material is consistent and a wider range, particularly fine grades, of particle sizes may be produced. As any oversize material is recycled, the yield is optimised. The throughput of cellulosic material is maximised as the residence time in the grinder/classifier unit is optimised. The invention also provides a method of production of cellulosic material in which the energy requirement is optimised.

Claims

1. A method for producing cellulose-based excipients comprising the steps of: -

setting a desired operating load on a grinder (10);

delivering coarse cellulosic material from a feed hopper (1) to the grinder (10);

grinding the coarse cellulosic material;

classifying the ground cellulosic material in a classifier (11) having a classifier drive unit (15);

controlling the classifier drive unit (15) in accordance with the operating load on the grinder (10);

drawing the ground and classified cellulosic material into a grinder receiving bin (23);

delivering the ground and classified cellulosic material to a separator (30);

separating the classified cellulosic material into cellulosic material of a desired size and oversize material;

delivering the cellulosic material of a desired size into a holding bin (41); and

packing the cellulosic material from the holding bin (41).

2. A method as claimed in claim 1 wherein the ground and classified material is drawn into the grinder receiving bin (23) by a fan (20) having a variable speed drive (21) and the method includes the step, prior to delivery of the coarse cellulosic material to the grinder (10), of setting the speed of the fan drive (21) to a desired speed matched to the coarse cellulosic material.

3. A method as claimed in claim 1 or 2 including the step of delivering the oversize cellulosic material from the separator (30) to the feed hopper (1) for recycling.

4. A method as claimed in any preceding claim wherein the operating load on the grinder drive is sensed by sensing the operating power of the grinder drive, the classifier drive unit (15) is a variable speed drive (15) and the classifier drive unit (15) is controlled by varying the drive speed of the classifier (11) in accordance with the operating power of the grinder drive.

5. A method as claimed in any preceding claim wherein a rotary air valve (2) is provided at the feed hopper outlet and the coarse cellulosic material is delivered from the feed hopper (1) to the grinder (10) by a blower unit (3).

6. A method as claimed in any preceding claim including the step of de-bagging one or more coarse cellulosic materials into the feed hopper (1).

Ansprüche

1. Verfahren zum Herstellen von auf Cellulose basierenden Hilfsstoffen, welches die folgenden Schritte umfaßt: -

Einstellen einer gewünschten Betriebslast auf eine Mahlanlage (10);

Zuführen von grobem Cellulosematerial aus einem Aufgabetrichter (1) an die Mahlanlage (10);

Zermahlen des groben Cellulosematerials;

Klassieren des gemahlenen Cellulosematerials in einem Klassierer (11) mit einer Klassierer-Antriebseinheit (15);

Kontrollieren der Antriebseinheit (15) des Klassierers gemäß der Betriebslast auf die Mahlanlage (10);

Abziehen des gemahlenen und klassierten Cellulosematerials in einen Aufnahmebehälter (23) der Mahlanlage;

Zuführen des gemahlenen und klassierten Cellulosematerials an einen Separator (30);

Trennen des klassierten Cellulosematerials in Cellulosematerial einer gewünschten Größe und Grobkorn;

Zuführen des Cellulosematerials einer gewünschten Größe in einen Vorratsbehälter (41) und

Packen des Cellulosematerials aus dem Vorratsbehälter (41).

2. Verfahren nach Anspruch 1, worin das zermahlene und klassierte Material durch einen Lüfter (20) mit einem Antrieb (21) variabler Drehzahl in den Aufnahmebehälter (23) der Mahlanlage gezogen wird und das Verfahren den folgenden Schritt einschließt: Vor Zufuhr des groben Cellulosematerials an die Mahlanlage (10) Einstellen der Drehzahl des Lüfterantriebes (21) auf eine gewünschte Drehzahl, die dem groben Cellulosematerial angepaßt ist.

3. Verfahren nach Anspruch 1 oder 2, einschließlich des Schrittes der Zufuhr des Grobkorn-Cellulosematerials aus dem Separator (30) an den Aufgabetrichter (1) zum Recycling.

4. Verfahren nach einem der vorangehenden Ansprüche, worin die Betriebslast auf den Antrieb der Mahlanlage durch Abtasten der Betriebsleistung des Antriebs der Mahlanlage abgetastet wird, die Antriebseinheit (15) des Klassierers ein Antrieb (15) mit variabler Drehzahl ist und die Antriebseinheit (15) des Klassierers durch Variieren der Antriebsdrehzahl des Klassierers (11) gemäß der Betriebsleistung des Antriebs der Mahlanlage kontrolliert wird.

5. Verfahren nach einem der vorangehenden Ansprüche, worin ein Drehluftventil (2) am Ausgang des Aufgabetrichters vorgesehen ist und das grobe Cellulosematerial durch eine Gebläseeinheit (3) aus dem Aufgabetrichter (1) an die Mahlanlage (10) zugeführt wird.

6. Verfahren nach einem der vorangehenden Ansprüche, einschließlich des Schrittes des Herausnehmens eines groben Cellulosematerials oder mehrerer grober Cellulosematerialien in den Aufgabetrichter (1).

Revendications

1. Un procédé de production d'excipients à base de cellulose englobant les étapes suivantes :

réglage d'une charge de fonctionnement souhaitée sur un broyeur (10) ;

alimentation en matériau cellulosique grossier à partir d'une trémie d'alimentation (1) jusqu'au broyeur (10) ;

broyage du matériau cellulosique grossier ;

tri du matériau cellulosique broyé dans un tamis cribleur (11) ayant une unité d'entraînement (15) de tamis cribleur ;

contrôle de l'unité d'entraînement (15) du tamis cribleur conformément à la charge de service sur le broyeur (10) ;

soutirage du matériau cellulosique broyé et trié dans un silo récepteur (23) du broyeur ;

envoi du matériau cellulosique broyé et trié dans un séparateur (30) ;

séparation du matériau cellulosique trié en matériau cellulosique d'une granulométrie souhaitée et matériau surdimensionné ;

envoi du matériau cellulosique d'une granulométrie souhaitée dans un silo de maintien (41) ; et

conditionnement du matériau cellulosique à partir du silo de maintien (41).

2. Un procédé selon la revendication 1, selon lequel le matériau broyé et trié est soutiré dans le silo récepteur (23) du broyeur par un ventilateur (20) ayant un moteur à vitesse variable (21) et le procédé englobe l'étape, avant l'envoi du matériau cellulosique grossier dans le broyeur (10), de réglage de la vitesse du moteur de ventilateur (21) jusqu'à une allure souhaitée adaptée au matériau cellulosique grossier.

3. Un procédé selon la revendication 1 ou 2, qui englobe l'étape d'envoi du matériau cellulosique surdimensionné à partir du séparateur (30) jusqu'à la trémie d'alimentation (1) pour le recyclage.

4. Un procédé selon l'une quelconque des revendications précédentes, selon lequel la charge de service du moteur du broyeur est détectée par captage de la puissance de fonctionnement du moteur du broyeur, l'unité d'entraînement (15) du tamis cribleur est un moteur à vitesse variable (15) et l'unité d'entraînement (15) du tamis cribleur est contrôlée en faisant varier la vitesse d'entraînement du tamis cribleur (11) conformément à la puissance de fonctionnement du moteur du broyeur.

5. Un procédé selon l'une quelconque des revendications précédentes, selon lequel une vanne d'air rotative (2) est prévue en sortie de la trémie d'alimentation et le matériau cellulosique grossier est envoyé à partir de la trémie d'alimentation (1) dans le broyeur (10) par une soufflante (3).

6. Un procédé selon l'une quelconque des revendications précédentes, qui englobe l'étape de désensachement d'un ou plusieurs matériaux cellulosiques grossiers dans la trémie d'alimentation (1).

Drawing