Such a tablet compressing machine is known from the document DE 20 2007 003 176 U1. The document DE 20 2007 003 176 U1 describes a tablet compressing machine, in which a cleaning liquid can be distributed, submerging the rotor and wherein ultra-sonic waves can be applied in the sealed housing to cleanse particles off from surfaces. Another tablet compressing machine is known from the document EP 0 637 507 A1. The document EP 0 637 507 A1 describes a method of washing a tablet compressing machine, wherein in a first step a cleaning liquid is distributed. In a second step, a flushing liquid is distributed and the liquid sucked out of the housing. In a third step, all openings of the housing are closed and a vacuum is applied to dry the sealed housing quickly.
Generic tablet compressing machines normally have a rotor unit comprising a die plate, an upper stamp holder and a lower stamp holder. The die plate is provided with a plurality of bores for inserting the upper or lower stamp during rotation. Thereby the upper and the lower stamps compress powdery material into shaped tablets. The upper and lower stamps are movably arranged in axial direction in associated upper and lower stamp holders. After the tablet has been compressed within a bore in the die plate, it is normally pushed out of the corresponding bore of the die plate by the lower stamps. The combination of upper stamps and holders, die plate and lower stamps and holders is called a rotor unit. Generic tablet compressing machines have a capacity of 500 to 25,000 tablets per minute depending upon the number of upper and lower stamps and the speed with which the rotor rotates.
When changing to another batch, that is when the powdery material is changed, for introducing a new powder which is to be compressed, the previous powder must first be completely removed from the machine. No residues of the previous powder should get into the surrounding air, which is why the rotor units in tablet compressing machines are normally encapsulated in a sealed housing. Generic tablet compressing machines are usually equipped with a spraying apparatus by means of which a cleaning liquid such as water may be distributed for removing the residual medical substance. Powder components suspended in air are captured by the spray mist and bound by the liquid, whereupon they sink down and settle on horizontal surfaces of the rotor unit and its vicinity. Powder residues already laying on surfaces are bound in the same way. The cleaning liquid together with the bound powder residues forms puddles on horizontal surfaces which do not drain away. These surfaces may, for instance, be formed on the rotor unit, on ancillary units and parts of the housing. Usually the rotor unit and the spraying facility are at least partially disposed within the sealed housing so that no powder components can pass into the surrounding area during tablet production.
In order to drain the cleaning liquid off the tablet compressing machine it is known in the prior art to provide only inclined, that is non-horizontal surfaces within the tablet compressing machine, thus avoiding the forming of puddles. However, a lot of effort is required to provide only non-horizontal surfaces in such a complicated machine as a tablet compressing machine, in particular when a plurality of components are involved.
This is the state of the prior art on which the invention is based. The invention is aimed at reducing the work and effort involved in constructing and manufacturing a tablet compressing machine.