The known prior art teaches the use of screw presses having the shape of a truncated cone, with screws presenting a pitch and diameter decreasing in the direction of the discharge, in order to obtain the compaction of the waste materials.

Apparatuses of this type are for example described in documents DE 34 29 848 A1, EP 0 239 858 A1, EP 0 790 122 A2 and EP 1 193 045 A1.

In all apparatuses of known type the screw press is arranged with its axis horizontally, so that it occupies a large space in plan view and it must be positioned at a suitable distance from the floor in order to be able to arrange below its discharge mouth a container of sufficient capacity for the collection of the compacted material.

The screw of the press is supported in an overhanging manner by its end which is motor driven, usually by means of bearings which are subjected to concentrated radial stresses of elevated degree, due to the weight of the said screw, whenever same is not supported by the material being compacted.

Whenever in the waste materials to be compacted there are present liquids, by using the screw presses of known type, it is difficult to effect a separation by gravity of the said liquids from the compacted material, even if the taper of the screw is in the order of about 20°, as shown for example in document DE 34 29 848 A1.

The invention obviates these and other inconveniences of the known art, with the following idea of solution.

The screw press is inclined upwardly with its discharge mouth, so that its longitudinal axis forms with the horizontal an angle comprised between 10° and 80°, preferably greater than 20°, for example in the range from 45° to 50°. By this simple solution, the following advantages are obtained. The screw press occupies in plan view a space which is less long than the space actually required. The discharge

mouth of the press results to be at a remarkable distance from the ground, so that also the height of the apparatus can be more reduced than that of the known apparatuses. The press can be in fact located at a short distance from the ground with its motorised portion and its discharge mouth results to be at a distance from the ground which is sufficient in order to be able to position below same a high capacity container for the collection of the compacted material. Thanks to the remarkable inclination, the liquids contained in the waste materials tend to remain by gravity in the initial portion of the screw, where it is easy to provide apertures for the drainage and removal of same even due to the only effect of gravity, into an underlying collecting container, either for the direct conveyance or by means of a pump into the sewage system or inside a high capacity container placed at the side of the container for the collection of the compacted waste materials. Another advantage derives finally from the improved operational condition of the bearings which support in an overhanging manner the screw, inasmuch as the weight of the screw is now discharged onto the said bearings in a more distributed manner, with an axial component and a lesser concentrated radial load.

These and other characteristic features of the invention, and the advantages deriving therefrom, will appear better evident from the following description made with reference to the two attached sheets of drawings, in which: Figures 1 and 2 show in side elevation and with parts in section an apparatus of the type referred to, with the inclined screw press and with different solutions for the removal of the liquids which have been extracted from the compacted waste materials.

In the Figures, reference numeral 1 indicates the screw press having the shape of a truncated cone with its pitch which is decreasing in the direction of the discharge, which is carried in a rotatable manner by a support member 102 by means of bearings 3 arranged at the extremity by which the said screw is driven into rotation thanks to a gearmotor 4 flanged to the said support 102, the said screw being rotatably mounted by its initial portion having a greater diameter at the bottom of a hopper 2 and rotating inside a body 5 which is laterally flanged to the said

hopper and onto which there is flanged the discharge mouth 6 which carries laterally a collar 7 made of bronze or other suitable material for its co-operation with the terminal portion of the screw and which carries at its end a door 8 which is swingable about the upper and transversal fulcrum 108, against the action of elastic and adjustable means 9 which urge same into closure position and which constitute a choking means, which opposes the discharge of the material from the mouth 6 and therefore contributes to a further compaction of the material which has been pre- compacted by the conical shape and by the decreasing pitch of the screw 1. The body inside which the screw rotates is provided with longitudinal grooves 100 which can be projecting and/or recessed and which due to reaction impart to the compacted material the required translation component towards the discharge mouth 6.

At a lower position and at the exterior of mouth 6 there is provided a relief portion 106 with a front arcuate shape which serves as a dripping member and to which there can be fastened a chute 206 which correctly guides the discharged material from the said mouth into the underlying collecting bag S supported by a horizontal frame 10 (see further). Above the hopper 2 there is provided a chamber 11 of known type, provided with side doors 111 which can be opened and closed in automatic, semi-automatic or manual manner, and which control corresponding window apertures through which it is possible to introduce into the said hopper the waste material which the screw press will compact and discharge with limited dimensions into the said collecting bag S.

The characterising feature of the present apparatus, as above explained, resides in the fact that the said press is inclined upwardly with its discharge mouth 6 and that its longitudinal axis Z forms, with respect to the horizontal, an angle A comprised between 0° and 80°, preferably greater than 20°, and for example in the range of about 45° to 50°. This condition permits the achievement of the important advantages which have been cited in the introduction, among which a smaller load radially on the bearings 3, a smaller length and height of the apparatus, the possibility of placing below the discharge mouth of the press a bag S having a relevant height and consequently a great capacity and above all the possibility (which

was not obtainable before) of effecting an immediate separation even due only to gravity, from the solid waste materials which are compacted under the action of the screw 1, of the liquids contained in the said waste materials and which can be added to same for sanitary purposes inside chamber 11 or in the zone of connection with the hopper 2. In order to effect this separation, the screw 1 is provided in its initial portion with a disc 101 presenting holes or slots (not shown) distributed along its perimetric portion, the said disc being arranged with a suitable clearance, useful for the drainage of the liquids, with respect to a channel 12 obtained in the lowermost portion of the hopper 2, which partially concerns also the support member 102. In the embodiment of Figure 1 the discharge of the channel 12 is controlled by an intercepting valve 13, of any suitable type, which whenever is opened consents the discharge by gravity of the liquid inside an underlying flat-shaped container 14 having a high capacity. In the embodiment according to Figure 2 the discharge outlet of the channel 12 is connected with a U-shaped duct 15 which by its terminal portion discharges into a high capacity container 14'placed at the side of the bag S for collecting the compacted waste, in the lower intermediate portion of the said duct there being arranged a motor pump 16 which forces the liquid towards said container. In the high zone of the duct from the channel 12 to the pump 16 there is provided a sensor 17, for example of the capacitive type, which starts the pump each time it senses an accumulation of liquid at the interior of the said duct 15. It is to be understood that the pump 16 can be connected directly to the discharge of the channel 12 and that the sensor 17 can be placed along the portion of duct 15 between the pump itself and the collecting container 14'. If the apparatus is placed in a zone where it is accessible a discharge opening to the sewage system, then of course the drained liquids can be conveyed directly into said discharge, by gravity of through the pump 16, so as to eliminate the requirement of the container 14 or 14'.

The bag S and the container 14 or 14'can be placed in a space inside the apparatus provided with a door or, even better, with a drawer which can be extracted from the side of the apparatus, for enabling the removal and the substitution of these components whenever suitable sensors of known type (not shown) detect the filled

condition of same and signal the need of performing this operation. According to a further solution, which has been diagrammatically indicated in the drawings, in consideration of the fact that the bag S and the container 14 or 14'are very heavy when they are full, there can be provided the possibility of rendering easy their transportation, by placing same on a carriage structure 18 which is arranged so as to be easily inserted and extracted from the apparatus, and if the case substituted with a reserve carriage carrying a new bag and container, so as to ensure the continuous operation of the apparatus. Safety means are obviously provided in order to subordinate the operation of the apparatus to the correct insertion of the carriage 18 into the apparatus itself. To the said carriage 18 there can be associated the upper portion 19 of the covering hood of the apparatus, which is placed in front of the discharge mouth 6 of the screw press, this portion being in any case conceived as removable for rendering easy the maintenance of the compacting device 8,9.