Description

Machine for cores coating

Technical Field

The present invention fits into the technical sector relative to the production of coated cores, that is to say, coated with a layer of coating material designed to give the cores particular properties, such as increased hardness, insolubility or controlled release, or other properties.

In particular the present invention relates to a machine for applying and fixing said coating.

Background Art

It is known that various types of so-called "cores", such as food or pharmaceutical tablets or other similar products, are coated with a layer of protective material which adheres to their outer surface. Said layer normally makes the surface of the core more resistant to the abrasions and handling which precede its packaging, and in any case make it smoother and shinier, and therefore more aesthetically pleasing. In pharmaceutical applications coating materials with delayed or controlled release are also used. In this way the active ingredient is carried without being dispersed to the desired site of action or absorption, or in any event it does not come into contact with the patient's mouth. The coating products are normally in liquid form, and comprise the coating product itself and a binding agent.

It is known the application of the coating layer in suitable coating machines equipped with a rotary drum, technically called "coating pan". The cores to be coated are inserted in the coating pan, in which there is one or more nozzles for applying the coating product by spraying it on. The coating pan is rotated to continuously mix the cores during the coating operations. The inner surface of the coating pan is also usually fitted with a plurality of suitably positioned winglets, designed to promote said mixing.

In the coating operations it is particularly important that all of the cores are subjected to the drying air flow in a substantially uniform way. To improve the methods for exposing the cores to the air flow, in prior art coating machines there were, for example, devices designed to suspend the cores in an air flow through a duct which comes out of the lower part of the coating pan and goes back into the upper part of the coating pan. However, such treatments may scratch or chip a significant number of cores, due to the stresses to which they are subjected along the path. In some known coating machines there is also a tubular device positioned inside the coating pan, called a "paddle" designed to extract hot air for drying the coating, blown into the coating pan through a suitable inlet duct . At the same time the paddle also contributes to the continuous mixing of the cores in the coating pan.

The paddle generally consists of a tubular duct which penetrates the coating pan axially, and which has one or more fixed extensions projecting downwards, where the mass of cores to be coated is housed. It is also connected to a suitably sized filter device, designed to remove dusts and coating product residues from the air before conveying the air to the outside. The extensions, and at times also the duct, have openings through which the air is extracted.

The above-mentioned extensions also have a removable end part which can be substituted with another having a different length. This means that they can be lengthened or shortened depending on the quantity of cores to be coated present in the coating pan. This allows improved penetration of the extensions in the mass of cores, but does not have any substantial effect on the core mixing methods.

Disclosure of the Invention

The main aim of the present invention is to provide a machine for the application of a coating layer on cores which allows a high level of core mixing to be achieved during the coating application and drying steps, without damaging the coated cores.

Another aim of the present invention is to provide a machine in which the shape of the paddle is easily adaptable to the different load situations.

The above-mentioned aims are completely achieved as described in the claims herein.

Brief Description of the Drawings

The characteristics of the invention, in accordance with the claims herein, are apparent in the following detailed description, with reference to the accompanying drawings, in which:

- Figure 1 is a perspective view from the outside of a machine for applying a coating layer made in accordance with the present invention;

- Figure 2 is a longitudinal section of the machine from Figure 1;

- Figure 3 is a perspective view of a paddle of the machine from the previous figures;

- Figure 4 is a perspective view of a second embodiment of the paddle of the machine from Figures 1 and 2 ; - Figure 5 is a cutaway perspective view of the paddle from Figure 4 ;

- Figure 6 is a schematic longitudinal section of the coating pan of the machine from Figures 1 and 2 ;

- Figure 7 is a schematic view of a section according to line VII - VII from Figure 6;

- Figure 8 is a cross-section according to line VIII - VIII from Figure 7.

Detailed Description of the Preferred Embodiments of the Invention With reference to Figures 1 and 2 the numeral 100 denotes a machine for applying a layer of protective coating, or a coating machine, on cores such as tablets for pharmaceutical use or food, or other similar products .

The coating machine 100 comprises a rotary container 10 or "coating pan", designed to contain a mass of cores 1 to be coated, having a substantially symmetrical shape relative to its own axis of rotation X. The coating pan 10 has an inlet mouth 11 for the

cores 1, symmetrical relative to the above-mentioned axis X, and a door 12 for closing the inlet mouth during the coating operations . The shape of the door 12, illustrated in Figure 1, is also new and original, and forms the subject matter of a separate patent application filed under today's date by the same Applicant at No. B02005A 000436.

The coating pan 10 is rotatably supported by a fixed supporting structure 20, designed to hold it in an operating position at an angle to the horizontal level. The angle of inclination is preferably between 10° and 60°.

A motor 30, also supported by the supporting structure 20, is designed to drive the rotation of the coating pan 10, with suitable speeds and timed operation after commands issued manually or according to predetermined programs from a control unit 25, in a substantially known way.

The coating pan 10, the motor 30 and the supporting structure 20 are suitably housed in a containment box 2, made according to known operating, safety and aesthetic criteria.

Inside the coating pan 10 there are applicator parts 40, of the known type, designed to apply the nebulised coating product on the cores 1, directing it towards the mass of cores contained in the coating pan 10, so as to deposit a layer of the product on them.

Fixed to the door 12 there is a inlet duct 4, designed to convey into the coating pan 10 air at a predetermined temperature and pressure arriving from a source of the known type, also housed in the above-mentioned box 2. Said source is housed in the same box 2, therefore the inlet duct 4 goes into it again after a short external path. Inside the coating pan 10 there is also a drying device 50, designed to extract from the coating pan 10 the air for drying the layer of coating product, blown in by the above-mentioned inlet duct 4, and then to convey it towards a filter unit of the known type and not described in detail. In said filter unit any product residues and dusts in suspension are removed from the air before it is expelled to the outside. The drying device 50 is also

designed to affect the mass of cores 1 to facilitate mixing during the coating product application and drying steps .

In accordance with the invention, the drying device 50 comprises (see also Figure 3) a tubular exhaust manifold 51, which penetrates the coating pan 10 through the door 12. The exhaust manifold 51 is connected to an exhaust duct 52, visible in Figure

1, in turn connected to the filter unit.

The manifold 51 is fixed to the cover 12 by a flange 53, having a plurality of slots 54 designed to define the angular position of the manifold 51.

The exhaust manifold 51 extends inside the coating pan 10 substantially perpendicularly to the inlet mouth 11 and, therefore, parallel with the axis of rotation X of the coating pan 10. The drying device 50 also comprises an adjustable intermediate tubular portion 55 which continues the exhaust manifold 51, at a predetermined angle α to the latter. In the embodiment illustrated in the accompanying drawings said angle α is such that the intermediate portion 55 is angled according to a substantially vertical direction.

In particular, the intermediate tubular portion 55 consists of an upper part 56 and a lower part 57, adjacent to the former and substantially at a right angle to it.

The upper part 56 in turn consists of two elements, respectively inner 56a and outer 56b, connected to one another telescopically, in such a way as to allow variation of the length of the upper part and rotation of the outer element 56b relative to the inner element 56a around the shared axis of symmetry of both elements . For this purpose, in a first embodiment illustrated in Figure 3, there are adjusting and fixing means 58 for adjusting the above-mentioned telescopic connection and stabilising it in the desired position. The adjusting and fixing means 58 comprise an open collar 58a, positioned at the upper end of the outer element 56b and open at its ends. A pair of opposite blocks 58b, 58c is fixed to the ends of the collar 58a, and a bolt 58d engages in through-holes made in the blocks 58b, 58c to loosen or tighten the collar 58a.

In a second embodiment of the intermediate portion 55, illustrated in Figures 4 and 5, there are adjusting and fixing means 59 comprising an inner axial tube 156a, axially fixed to the inner element 56a and an outer axial tube 156b, axially fixed to the outer element 56b.

The latter leads to the outside at the bottom at the elbow formed by the upper part 56 and the lower part 57 of the intermediate portion 55. The inner and outer tubes 156a and 156b are connected to one another telescopically, with the possibility of sliding axially and rotating relative to one another, around their axis of symmetry.

Inserted in the inner and outer tubes 156a and 156b there is an adjusting rod 157 which comes out of the bottom and in its lower end has an operating key 158 accessible from the outside, for setting the position of the tubes 156a, 156b and, consequently, of the inner and outer elements 56a and 56b of the drying device 50.

The adjusting rod 157 is preferably connected to the axial tubes 156a, 156b by a threaded connection, but there may be a different type of connection, for example using friction.

The drying device 50 also comprises an end portion 60, designed to supply the cores 1 with a flow of drying air and to affect the cores and facilitate their mixing.

In particular, the end portion 60 comprises a substantially tubular connecting part 61, adjustably fixed to the lower part 57 of the intermediate portion 55, and a paddle 62 angled downwards substantially at a right angle to the latter. In the embodiments illustrated, the paddle 62 roughly has the shape of a duck's bill, the width increasing from the upper part to the lower part, and it has suitable holes made in the lower part, designed to pick up air from the mass of cores 1 as evenly as possible.

The end portion 60 is connected to the intermediate tubular portion 55 by a rotary flange 160 with slots, and there are adjusting means 65 for axially rotating the end portion 60 relative to the intermediate portion 55.

Said adjusting means 55 comprise, in detail (Figures 3, 4 and 5) , a first axial tube 66, in the lower part 57 of the

intermediate portion 55, a second axial tube 67, in the connecting part 61 and leading to the outside of the latter, and a fixing and adjusting rod 68. The latter is inserted in the axial tubes 66, 67, and can be operated from the outside to lock or release the connection between the intermediate portion 55 and the end portion 60. More precisely, the fixing rod 68 is preferably fixed to the first axial tube 66 and is slidably inserted on the second tube 67. It also has threading in its outer portion, and is connected to a corresponding threaded nut 69, so that, when the latter is loosened, the end portion 60 can rotate through a desired angle by means of the rotary connection created by the flange 160. Said connection basically has a plurality of slots 161 on the flange 160, in which an equal number of pins 162 located at the end of the intermediate portion 55 engage. It should be noticed that, from a structural viewpoint, the direction of the air flow in the coating pan 10 could be inverted simply by inverting the connection of the two ducts described above. That is to say, if appropriate, the drying device 50 may blow hot air directly into the mass of cores 1, and the duct 4 referred to as the "inlet" duct instead blows out the excess air to the filter unit .

The coating machine 100 disclosed also comprises (see Figures 6 to 8) a plurality of mixing winglets 70, positioned on the base of the coating pan 10 radially relative to the axis of rotation of the pan.

Each of the mixing winglets 70 basically follows the course of the base of the coating pan 10 and has a piece 71, convex with a roughly constant cross-section, so as to gently move the cores 1 during treatment. Also connected to the outermost part of the piece 71 with the constant cross-section is an end winglet 72, curved and raised relative to the piece 71. The end winglet 72 is preferably removably fixed to the piece 71 with a constant cross- section, and can be substituted with other end winglets having different shapes, or its position is made height and angle adjustable, depending on requirements.

The inlet mouth 11 of the coating pan 10 is suitably formed to create, together with the door 12 and the edge of the box 2, a

seal, essential for avoiding dispersal of the coating product and dusts from the cores 1 treated, which may contain pharmaceutical active ingredients or in any case substances which must not come into contact with the operators or other personnel present. The machine 100 according to the present invention advantageously allows, for any type of core 1 to be coated and for any quantity of cores, the achievement of optimum conditions for core mixing, thanks to the shape of the paddle 62 and above all the degrees of freedom for its positioning. Said degrees of freedom are provided by the different methods of adjusting the drying device 50, that is to say, in particular by the possibility of rotating the manifold 51 by means of the flange 53, the possibility of rotating the outer element 56b of the intermediate portion 55 about its own axis and varying its height, and rotating the paddle 62 by rotating the flange 160.

All of this gives an infinite variety of paddle 62 positions relative to the mass of cores 1 present in the coating pan 10, both in terms of the angle relative to the rotation of the coating pan 10 and in terms of the depth of insertion of the paddle 62 in the mass of cores 1. Mixing is further facilitated by the presence of the winglets 70 as described.

The above description is provided by way of example only and is not limiting. Therefore, the invention may be modified and adapted without thereby departing from the inventive concept which covers the solution described above and in the claims herein.