The present invention relates to press machines suitable for producing tablets, lozenges, and pills for pharmaceutical use, food use, and chemical use and in particular to a rotary press machine provided with a system for rejecting or sampling the tablets manufactured. The invention also relates to a method for rejecting or sampling tablets manufactured in a press machine.

The known rotary press machines comprise a compression turret, rotating about a vertical axis and formed by a die table or plate provided with a plurality of dies, i.e., through cavities, angularly distributed, equidistant from each other, along a circumferential portion of the same table and arranged to receive a powdered or granular product dispensed in a dedicated dosing station. The turret further comprises a plurality of upper punches and lower punches associated in pairs with the respective dies and moved linearly and vertically, coaxially to the dies, by cams and compression rollers during the rotation of the turret.

The lower punches form with the dies suitable seats or dosing chambers able to receive in the dosing station the product to be compressed.

In a subsequent compression station the upper punches and lower punches are moved by compression rollers in order to compress the product introduced into the dies so as to create the tablets, which are then extracted from the dies of the table by means of the lower punches, suitably lifted, and therefore conveyed in an outlet chute corresponding to an outlet station. The various tablet manufacturing steps are performed during a revolution rotation of the compression turret which rotates with generally continuous motion.

At the outlet chute, a reject system is usually provided that diverts the tablets manufactured that do not meet the production requirements, among which size, hardness, porosity and weight, into an appropriate reject duct. These parameters are detected, for example, by measuring a compressive force exerted by the punches in the single dies or a height of the product dosed inside the dies or the mass of the tablets by means of microwave sensors or based on magnetic resonance technology or by directly measuring the weight of the tablets by means of electronic scales or load cells.

The reject system typically comprises a movable diverting element, mechanically movable by an electrical or pneumatic actuator into an operative position in order to divert the tablets to be rejected into the reject duct; the regular tablets are instead conveyed into a main duct of the aforementioned outlet chute. Likewise the known press machines may comprise, generally at said outlet chute, a sampling system intended to divert a group or sample of manufactured tablets into a sampling duct, for example to undergo thorough examinations and extensive quality controls.

For this purpose, the sampling system comprises a respective movable diverting element, mechanically movable by an electric or pneumatic actuator in an operative position to divert the tablets to be sampled into the appropriate duct.

A disadvantage of the known reject systems and sampling systems lies in that at high operating speeds of the press tablet machine (i.e. at high rotation speeds of the compression turret) they allow respectively a reject and sampling of cumulative type, i.e. the reject and sampling of a plurality of tablets in succession, since the low speed of mechanical actuation of the movable diverting elements does not allow the diverting elements to select and divert the tablets singly, i.e. to perform a so-called single reject and a sampling.

The single type sampling is, however, very useful and important because it allows, for example, t tp sample and subsequently to analyse only specific tablets exiting from the press machine, for example those manufactured by a specific pair of punches of the plurality of pairs of punches (upper and lower), typically in order to verify the correct operation of said specific pair of punches.

US 2010/094449 discloses a system for rejecting tablets manufactured in a rotary press machine which comprises an ejection nozzle for separating defective tablets. The ejection nozzle is fed with compressed gas through a supply line having an inlet end for connection with a source of compressed gas and an outlet end communicating with the ejection nozzle. The supply line is equipped with a control valve that is controlled by a control unit in order to open the supply line when a defective tablet has been detected by the control unit. The supply line is equipped with a sensor positioned between the control valve and the inlet end of the supply line and suitable for detecting a parameter indicative of a gas flow through the control valve so that the control unit generates an error signal in case of malfunction of the control valve.

US 2017/080662 discloses a rotary tablet press machine, having a table rotatable about a vertical rotation axis and provided with a die with holes for producing tablets within said holes by means of pairs of punches. The press machine comprises at least one filling station, having at least one pressing station and having at least one tablet outlet for extracting the tablets manufactured by the rotary press machine. A rejecting device is associated to the outlet by means of which the tablets, according to a control signal, can be supplied as single tablets to a first channel or as a flow of tablets to a second channel. To allow an increase in production at the outlet, a weighing device is associated with a weighing cell, wherein the tablets of the first channel can be fed to the weighing device via a supply channel.

US 2021/221085 discloses a reject chute for a machine for making tablets and a method for selecting the tablets after they have been made in the machine for making tablets. The reject chute comprises channels in which the tablets are guided and/or sorted after their production which are arranged on two planes. Sorting of the tablets is carried out by means of sorting devices arranged in tandem. A sorting device comprises two bars which are preferably designated as sorting bars and as separating bars. The sorting bar comprises a linear drive, which is connected by an oscillating lever to the separating bar. If the sorting bar moves upward from the rest position to the sorting position, the separating bar automatically descends downward and releases the opening of the sorting channel.

It is an object of the present invention to improve known tablet press machines, in particular rotary press machines provided with systems for rejecting and sampling the tablets manufactured.

A further object is to provide a press machine that selectively allows the manufactured tablets to be singly rejected or sampled precisely and accurately, in particular in order to perform single reject and sampling.

A further object is to provide a press machine provided with an efficient and precise reject and sampling system and that is at the same time simple and economical to construct.

Yet another object is to provide a method for rejecting and sampling tablets manufactured in a press machine, in particular for selectively rejecting or precisely and accurately sampling singly manufactured tablets so as to achieve single reject and sampling.

A first aspect of the invention provides a tablet press machine according to claim 1.

A second aspect of the invention provides a method for rejecting and sampling the tablets in a press machine according to claim 7.

The invention can be better understood and implemented with reference to the attached drawings which illustrate an exemplary and non-limiting embodiment thereof, in which: figure 1 is a schematic and simplified plan view of the rotary tablet press machine of the invention, provided with a reject and sampling system for the manufactured tablets, arranged in a production configuration; figure 2 is a partial plan view of the press machine of figure 1 illustrating the reject and sampling system in a sampling configuration; figure 3 is a partial plan view of the press machine of figure 1 illustrating the reject and sampling system in a reject configuration; figure 4 is a partial plan view of the press machine of figure 1 illustrating the reject and sampling system in a reject configuration in an initial adjustment step of the press machine.

Referring to figures 1 to 4, the rotary tablet press machine 1 according to the invention is schematically illustrated which comprises a compression turret 2 rotating about a rotation axis X, in particular vertical, and including a die table 3 provided with a plurality of dies 4, or through cavities, arranged to receive a product to be compressed and to make tablets 100. The dies 4 are carried out along a circumferential portion of the die table 3, angularly spaced apart from each other.

The press machine 1 further comprises a plurality of lower punches and upper punches, which are not illustrated because of a known type, associated in pairs to respective dies and a dosing station adapted to fill with a product the dosing cavities formed by the dies 4 closed below by the lower punches. Drive means, for example of the cam type, are provided to move the lower punches and/or the upper punches within the respective dies 4 in order to compress the product and obtain the tablets.

The press machine 1 also comprises conveying means 5 for conveying the tablets 100 made by the dies 4 of the die table 3 into an outlet duct 6, and a reject and sampling system 7 configured to divert established tablets 100 made by the dies 4 selectively into a reject duct 8 or into a sampling duct 9.

In particular, the reject and sampling system 7 comprises first diverting means 11 configured to act on single tablets to be rejected 100a so as to divert them from the die table 3 towards the reject duct 8, and second diverting means 12, distinguished from the first diverting means 11 and configured to operate on individual tablets to be sampled 100b so as to divert them from the die table 3 towards the sampling duct 9. More precisely, the first and second diverting means 11, 12 are configured to operate on a single tablet at a time so as to carry out a reject or a sampling of the single tablets.

In the embodiment shown in the figures, the first diverting means 11 and the second diverting means 12 comprise respective compressed air supply devices, of known type, suitable for emitting respective compressed air blows or jets capable of hitting and diverting a single tablet to be rejected 100a or a single tablet to be sampled 100b at a time, when extracted from the respective die 4 of the die table 3.

The outlet duct 6, which receives the tablets 100 extracted from the dies 4 (for example by suitably raising the lower punches), is arranged for example almost radially with respect to the die table 3. The conveying means 5 comprise a shaped and curved guide element 15 configured to be abutted by the tablets 100 that are extracted from the dies 4 and slide on an upper surface of the die table 4 so as to divert them into the outlet duct 6.

The reject duct 8 and the sampling duct 9 are arranged side by side and parallel to the outlet duct 6 and depart from the die table 3. The reject duct 8 is for example interposed between the sampling duct 9 and the outlet duct 6. The reject and sampling ducts 8, 9 and the outlet duct 6 are inclined downwards for example to allow the tablets to descend and slide easily by gravity.

The first diverting means 11 are arranged above the die table 3, upstream of the outlet duct 6, with reference to a advancement direction of tablets exiting from the dies 4, and in particular they face the mouth of the reject duct 8 so as to singly divert the tablets to be rejected 100a extracted from the dies 4 and push them into the reject duct 8.

Similarly, the second diverting means 12 are arranged above the die table 3, upstream of the outlet duct 6, and in particular they face the mouth of the sampling duct 9 so as to singly divert the tablets to be sampled 100b extracted from the dies 4 and push them into the sampling duct 9.

In particular, the second diverting means 12 are arranged on the die table 3 upstream of the first diverting means 11 with respect to the advancement direction of tablets.

The press machine 1 may also comprise sensor means arranged adjacent to the first diverting means 11 and the second diverting means 12 and configured to detect the passage, in particular the presence, of a tablet 100 in front of the first diverting means 11 and of the second diverting means 12.

A control unit 10 is provided that is connected to the first diverting means 11 and to the second diverting means 12 and is configured to selectively activate the diverting means 11 or the second diverting means 12 respectively when the tablet to be rejected or to be sampled is on the die table 3 and arrives in front of the first diverting means 11 or of the second diverting means 12 respectively.

The control unit 10 is, for example, the control unit that controls the operation of the whole press machine 1. For example, the control unit 10 can be connected to sensor means suitable for detecting a compressive force exerted by the punches inside the dies 4 and/or suitable for detecting other parameters of the tablets 100, such as size, hardness, porosity and weight that allow the control unit 10 to identify the manufactured tablets 100 that do not meet the production requirements, i.e. the tablets to be rejected 100a.

In particular, the control unit 10 identifies the tablets to be rejected 100a and the dies 4 of the die table 3 in which they are housed so as to identify such tablets when exiting the die table 3 and allow the reject and sampling system 7 to divert said tablets into the reject duct 8 or into the sampling duct 9.

The reject and sampling system 7 also comprises third diverting means 13 configured to divert an established plurality of tablets to be rejected 100a from the outlet duct 6 towards the reject duct 8, for example in an initial step of adjustment of the press machine 1 in which the tablets manufactured do not yet meet the production requirements.

The third diverting means 13 comprise, for example, a diverting element that can be moved in an operative position A in order to divert the established plurality of tablets to be rejected 100a from the outlet duct 6 to the reject duct 8. In particular, the diverting element 13 is inserted in a wall that separates the outlet duct 6 from the reject duct 8 and is rotated in the operative position A, in which it is inserted within the outlet duct 6 so as to intercept and divert the tablets to be rejected 100a which slide inside it.

The diverting element 13 is rotated by drive means of known type and not illustrated, for example electric or pneumatic drive means.

The operation of the rotary press machine 1 of the invention comprises extracting the tablets 100 from the dies 4 of the die table 3 and conveying them by means of the guide element 15 of the conveying means 5 into the outlet duct 6.

When a tablet to be rejected 100a, saved by the control unit 10 and extracted by the respective die 4, moves on the die table 3 in front of the first diverting means 11, the first diverting means are activated by the control unit 10 to divert and push the aforementioned tablet to be rejected into the reject duct 8.

Similarly, when a tablet to be sampled 100b, saved by the control unit 10 and extracted from the respective die 4, moves on the die table 3 in front of the second diverting means 12, the second diverting means are activated to divert and push the aforementioned tablet to be sampled 100b into the sampling duct 9.

It should be noted that the first diverting means 11 and the second diverting means 12 operate on the tablets 100 before they have left the die table 3.

The press machine 1 of the invention thus selectively allows the manufactured tablets to be rejected or sampled individually, in particular in order to perform a single reject and sampling.

More precisely, thanks to the use of diverting means 11, 12, in particular the pneumatic type blowing compressed air, a simple and economical reject and sampling system 7 is carried out, capable to operate on a single tablet at a time so as to perform in a precise and reliable way a single reject and sampling of the tablets 100 even at high operating speeds of the press machine 1.

In the case of sampling it is therefore possible to select and sample only established tablets, even if they are separated from each other in the die table 3 by other tablets not be sampled. For example, it is possible to sample all and only the tablets manufactured by a specific pair of compression punches to accurately and precisely control their operation.

The method of the invention for rejecting and sampling tablets, pills, lozenges and the like manufactured in a press machine 1 comprises the following steps: conveying tablets 100 manufactured by die 4 of a die table 3 of a compression turret 2 of the press machine 1 into an outlet duct 6; singly diverting tablets to be rejected 100a made by the dies 4 from the die table 3 towards a reject duct 8 by means of first diverting means 11; singly diverting tablets to be sampled 100b made by the dies 4 from the die table 3 towards a sampling duct 9 by means of second diverting means 12 which are distinct from the first diverting means 11 ; wherein the first and second diverting means 11, 12 operate on the tablets 100 before they have left the die table 3.

The step of diverting a single tablet to be rejected 100a is carried out by means of a jet of compressed air emitted by the first diverting means 11.

The step of diverting a single tablet to be sampled 100b is carried out by means of a jet of compressed air emitted by the second diverting means 12.

According to the method, the steps of diverting the single tablet to be rejected 100a or the single tablet to be sampled 100b are carried out respectively when the tablet to be rejected or to be sampled is on the die table 3 and arrives in front of the first diverting means 11 or of the second diverting means 12, respectively.

The method further comprises diverting a plurality of tablets to be rejected 100a from the outlet duct 6 towards the reject duct 8, in particular in an initial step of adjustment of the press machine 1, by means of third diverting means 13 thereof.

In particular, it is provided to divert the plurality of tablets to be rejected 100a from the outlet duct 6 to the reject duct 8 by means of a diverting element of the third diverting means 13. The method of the invention therefore allows tablets made by and extracted from the die table 3 of the press machine 1 to be selectively and singly rejected or sampled in a precise and accurate manner so as to achieve a single reject and sampling.