Method and machine for filling capsules or similar with at least two products, in particular pharmaceutical products in granules

Abstract

The bottom shell of a capsule is filled with at least two products, contained in respective tanks, by means of a metering device, which has a metering chamber for receiving a given quantity of product from each tank; and a transfer chamber, which receives and transfers the product from the metering chamber to the bottom shell, and has a weighing device for weighing the product inside the transfer chamber.

1 ) A machine for filling capsules or similar with at least two products, in particular pharmaceutical products in granules; each capsule comprising a bottom shell ( 2 ), and a top shell closing the bottom shell ( 2 );
 the machine comprising conveying means ( 11 ) for feeding each bottom shell ( 2 ) continuously along a given path (P); at least two tanks ( 15 ,  16 ) containing respective products; at least one metering wheel ( 3 ) mounted to rotate continuously about a respective substantially vertical axis ( 4 ); and a number of metering devices ( 18 ), each of which is fed by the metering wheel ( 3 ) along a portion of the path (P), in time with a respective bottom shell ( 2 ), to feed the products into the bottom shell ( 2 ), and comprises a metering chamber ( 19 ) for receiving a given quantity of product from each tank ( 15 ,  16 ); and the machine being characterized by each metering device ( 18 ) also comprising a transfer chamber ( 21 ), which receives and transfers the product from the relative metering chamber ( 19 ), and comprises a weighing device ( 25 ) for weighing the product in the transfer chamber ( 21 ).   
     
     
         2 ) A machine as claimed in  claim 1 , wherein the weighing device ( 25 ) comprises at least one capacitive transducer ( 24 ). 
     
     
         3 ) A machine as claimed in  claim 1 , wherein the weighing device ( 25 ) comprises a bushing ( 23 ) forming at least part of said transfer chamber ( 21 ). 
     
     
         4 ) A machine as claimed in  claim 3 , wherein the bushing ( 23 ) comprises at least one capacitive transducer ( 24 ). 
     
     
         5 ) A machine as claimed in  claim 1 , wherein each metering device ( 18 ) also comprises a feed chute ( 26 ) for feeding the products from the metering chamber ( 19 ) to the transfer chamber ( 21 ); and a piston ( 27 ), which defines the bottom of the metering chamber ( 19 ), and is movable, along the metering chamber ( 19 ) and parallel to said axis ( 4 ), between an open position and a closed position opening and closing the feed chute ( 26 ) respectively. 
     
     
         6 ) A machine as claimed in  claim 5 , and also comprising first actuating means ( 29 ) for moving the pistons ( 27 ) to and from their respective said open positions; the first actuating means ( 29 ) comprising a first cam ( 30 ) extending about said axis ( 4 ), and, for each piston ( 27 ), at least one first cam follower ( 31 ) fitted to the piston ( 27 ) and engaging the first cam ( 30 ). 
     
     
         7 ) A machine as claimed in  claim 5 , and also comprising a lock device ( 45 ) for selectively locking each piston ( 27 ) in the closed position. 
     
     
         8 ) A machine as claimed in  claim 7 , wherein, for each metering device ( 18 ), the lock device ( 45 ) comprises a respective lock member ( 49 ) movable between a lock position locking the relative piston ( 27 ) in the closed position, and a release position. 
     
     
         9 ) A machine as claimed in  claim 8 , wherein each first cam follower ( 31 ) is fitted slidably to the relative piston ( 27 ); a retaining device ( 34 ,  35 ) being provided to secure the first cam follower ( 31 ) axially on the piston ( 27 ) when the lock member ( 49 ) is in the release position. 
     
     
         10 ) A machine as claimed in  claim 9 , wherein the retaining device ( 34 ,  35 ) is designed to secure the first cam follower ( 31 ) axially on the piston ( 27 ) with less force than that exerted by the first cam ( 30 ) on the first cam follower ( 31 ) when the lock member ( 49 ) is in the lock position. 
     
     
         11 ) A machine as claimed in  claim 1 , wherein each metering device ( 18 ) also comprises a shutter ( 36 ), which defines the bottom of the transfer chamber ( 21 ), and is movable between an open position and a closed position opening and closing the transfer chamber ( 21 ) respectively. 
     
     
         12 ) A machine as claimed in  claim 11 , and also comprising second actuating means ( 39 ) for moving the shutters ( 36 ) between said open and closed positions; the second actuating means ( 39 ) comprising a second cam ( 39 ) engaged by the shutters ( 36 ). 
     
     
         13 ) A machine as claimed in  claim 11 , wherein the shutter ( 36 ) is substantially L-shaped, and comprises a stopper plate ( 42 ), and a supporting rod ( 40 ) supporting the stopper plate ( 42 ); the supporting rod ( 40 ) being substantially parallel to and offset with respect to a longitudinal axis ( 22 ) of the transfer chamber ( 21 ), and having a wedge-shaped portion ( 41 ) for dislodging any product clogging the transfer chamber ( 21 ). 
     
     
         14 ) A method of filling capsules or similar with at least two products, in particular pharmaceutical products in granules, on a machine comprising at least two tanks ( 15 ,  16 ) containing respective products; and at least one metering wheel ( 3 ) mounted to rotate continuously about a respective substantially vertical longitudinal axis ( 4 ), and having a number of metering devices ( 18 ); each capsule comprising a bottom shell ( 2 ), and a top shell closing the bottom shell ( 2 ); and the method comprising the steps of:
 feeding the bottom shells ( 2 ) continuously along a given path (P);   feeding each metering device ( 18 ) along a portion of the path (P), in time with a respective bottom shell ( 2 ); and   transferring a given quantity of each product from the relative tank ( 15 ,  16 ) to a metering chamber ( 19 ) of the metering device ( 18 );   the method being characterized by also comprising the steps of:   transferring the product from the metering chamber ( 19 ) to a transfer chamber ( 21 ) of the metering device ( 18 );   weighing the product in the transfer chamber ( 21 ) inside the transfer chamber ( 21 ) itself; and   transferring the product from the transfer chamber ( 21 ) into the relative bottom shell ( 2 ).   
     
     
         15 ) A method as claimed in  claim 14 , wherein the product in each transfer chamber ( 21 ) is weighed by means of at least one capacitive transducer ( 24 ). 
     
     
         16 ) A method as claimed in  claim 14 , wherein the product in each transfer chamber ( 21 ) is weighed inside a bushing ( 23 ) at least partly defining the transfer chamber ( 21 ). 
     
     
         17 ) A method as claimed in  claim 16 , wherein the bushing ( 23 ) comprises at least one capacitive transducer ( 24 ). 
     
     
         18 ) A method as claimed in  claim 14 , wherein the metering chamber ( 19 ) of each metering device ( 18 ) is closed at the bottom by a piston ( 27 ); the method also comprising the step of moving the piston ( 27 ) between a closed position, in which the metering chamber ( 19 ) is separated from the transfer ( 21 ), and an open position, in which the metering chamber ( 19 ) is connected to the transfer chamber ( 21 ). 
     
     
         19 ) A method as claimed in  claim 18 , and also comprising the step of selectively locking each piston ( 27 ) in the closed position. 
     
     
         20 ) A method as claimed in  claim 14 , wherein the transfer chamber ( 21 ) of each metering device ( 18 ) is closed at the bottom by a respective shutter ( 36 ); the method also comprising the step of moving the shutter ( 36 ) between a closed position, in which the transfer chamber ( 21 ) is separated from the relative bottom shell ( 2 ), and an open position, in which the transfer chamber ( 21 ) communicates with the relative bottom shell ( 2 ).