Description

Door for closing the coating pan of a machine for coating cores

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 invention relates to a door for closing the rotary drum container, or coating pan, of 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. Application of the coating layer in suitable coating machines is known, the machines equipped with a rotary drum, referred to in technical terms as the "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 tabs, 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. 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 have openings through which the air is extracted.

The components of the above-mentioned coating machines are normally housed in a suitably sized containment box. In the coating machines described above the coating pan has an inlet mouth for the insertion of the mass of cores to be coated and for their removal at the end of the coating operations. Said mouth is usually closed by a sealed door. Since the coating pan is rotated, the above-mentioned applicator, drying and air feed devices are inserted in it through the inlet mouth, and they are normally fixed to the door. Therefore, the door is held stationary and is fixed to the containment box. The seal is usually guaranteed by suitable dragging seals .

The coating machine configurations described above have a disadvantage deriving from the fact that, at the end of each coating cycle for a core load, in order to remove them from the coating pan the door must, obviously, be opened. This means that

all of the devices fitted on the door, that is to say, the applicator device, the drying device and the air inlet duct, must be moved and, if necessary, removed from the coating pan. They must then be returned to their correct positions, when the door is closed, after inserting the next load of cores to be coated in the coating pan.

Disclosure of the Invention

The main aim of the present invention is to propose a door for closing the coating pan of a coating machine which allows coating pan loading and unloading operations to be performed without having to move the above-mentioned devices .

Another aim of the present invention is to propose a door for closing the coating pan which is in any case able to allow the above-mentioned removal of the applicator device and the drying device, when necessary, in a simple, rapid and immediately reversible way.

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 first embodiment of a coating machine in accordance with the present invention;

- Figure 2 is a longitudinal section of the machine from Figure 1; - Figure 3 is a front view of the door for closing the machine illustrated in the previous figures;

- Figure 4 is a perspective view of the door from Figure 3 ;

- Figure 5 is a front view of a second embodiment of a coating machine in accordance with the present invention; - Figure 6 is a longitudinal section of the machine from Figure 5;

- Figure 7 is a front view of the device for closing the machine from Figures 6 and 7 ;

- Figure 8 is a cross-section according to line VIII - VIII from Figure 7 ; - Figure 9 is a cross-section according to line IX - IX 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 or "coating pan" 10, 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 symmetrical relative to the above-mentioned axis X, designed to allow the insertion of the cores 1 to be treated and their removal at the end of the treatment . 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 and approximately 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 completely 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 use known techniques 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.

Inside the coating pan 10 there is also a drying device 50, designed to use a paddle 62 to extract air, normally heated, for drying the layer of coating product, and to convey it towards the outside through a filter unit of the known type and not described in further detail. The drying air is blown into the coating pan 10 by a inlet duct 4 connected to a suitable hot air source not illustrated in the accompanying drawings.

The drying device 50 is also designed to affect the cores 1, with the paddle 62, to facilitate mixing during the coating product application and drying steps.

The shapes of the coating pan 10 and of the drying device 50, illustrated in Figures 2 and 5, are new and original, and form the subject matter of a separate patent application filed under today's date by the same Applicant at No. B02005A 000435. The machine 100 has a door 12 for closing it, hinged to the box 2 aligned with the axis of the inlet mouth 11 of the coating pan 10, and designed to removably block and seal the inlet mouth 11 during core 1 processing.

In accordance with the invention, the door 12 is substantially circular and comprises a fixed semi-circular portion 13, positioned at the top and hinged to the box 2 by a hinge 13a (Figures 3 and 4) , and a mobile semi-circular portion 14 which opens independently, complementing the fixed portion 13 and positioned below the latter. The fixed portion 13 has openings 131, 132, 133, respectively designed to allow the entry into the coating pan 10 of the applicator parts 40, the drying device 50 and the air inlet duct 4. In particular, the fixed portion 13 also supports said parts and devices, by means of suitable flanged connections. According to a first embodiment ^' of the invention, illustrated in Figures 1 to 4, the mobile portion 14 is connected to the fixed portion 13 by first connecting means 141, designed to connect the lower part of the fixed portion 13 to the upper part of the mobile portion 14. In particular, said first connecting means 141 comprise a pair of hinges 142, 143, positioned at the sides of the fixed and mobile portions 13 , 14. These hinges are designed to allow the mobile portion 14 to rotate around the

diametral axis of the door 12 to provide access to the coating pan 10, for loading, unloading or inspection, without having to completely open the door 12.

Attached to each hinge 142, 143 there is a rocker arm mechanism 144, having a corresponding pneumatic damper cylinder 145. The pair of damper cylinders 145 is designed to hold the mobile portion 14 in the open position, and to achieve gradual closure of said mobile portion even if it is accidentally released from the open position. According to a second embodiment of the invention, illustrated in Figures 5 to 9, the mobile portion 14 is connected to the box 2 by second connecting means 241, which connect the lower part of the mobile portion 14 to the containment box 2. Said second connecting means 241 substantially consist of a pair of hinges positioned in the box 2 at the sides of the mobile portion 14.

The mobile portion 14 also comprises fixing means 245, positioned in the upper part of the mobile portion 14 and designed to fix the latter to the fixed portion 13. As illustrated in Figure 9, the fixing means 245 basically constitute a pair of knobs 246, 247, fitted through and in such a way that they rotate freely in the upper part of the mobile portion 14.

Each knob 246, 247 has a perpendicular tab 248 at it inner end. When in the locking position said tab 248 is designed to engage with the inner face of the fixed portion 13 by means of friction.

In the second embodiment described above, the upper edge of the mobile portion 14 preferably overlaps the lower edge of the fixed portion 13, so that it is brought into contact with it in the closed position.

In both of the embodiments described, the present invention allows easy access to the coating pan 10 without necessarily having to remove the devices which penetrate it. However, if said devices have to be removed, for maintenance purposes, to substitute parts or for other reasons, this can be done in a

simple, rapid way, by opening the entire door 12 by rotating it around its upper hinge 13a.

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 also covers the solution described above and in the claims herein.