The present invention relates to a method for hygienic disposal of mainly organic waste from households, public kitchens, indust¬ ries, etc. by pulverizing, dewatering and drying the waste, the dried final product thereafter being collected in a container.

Furthermore, the invention relates to a means for performing the method mentioned above.

It is already known to feed previously pulverized waste into a means for waste destruction, where the waste after a dewatering is transferred to a chamber, where the waste is placed onto a grill in a combustion chamber. Thereafter, an electrical heating device with a reflector is lowered onto the top of the waste and the waste is dried. Thereafter, the temperature of the heating device is increased so that the waste is burnt.

Its is also already known to produce animal food out of garbage. The garbage is then compressed and is thereafter sterilized, dewatered by drying or by dehydration, is inspected, screened and granulated.

The hitherto known methods are time comsuming and circumstantial with a transfer of the treated waste between stations and with parts to be continously cleaned of the not very easily handable material.

It is the purpose of the invention to achieve a substantially easier method with a fast and safe device. According to the in¬ vention, this is achieved by that the method and the means are adapting the characteristics specified in the claims. This means, that the pulverizing, dewatering and drying and eventually a pow- dergrinding is performed in an ascending drying air stream pas¬ sing a mill, where the material is kept more or less air-suspen¬ ded during rolling until the material is dry och pulverized. The¬ reafter, the drying air stream is stopped and the material is instead sucked down and into a collecting container, the procedu¬ re thereafter being repeated with a new set of waste.

Thus, the complete treatment of the waste from its entering is performed in one and the same vertical chamber without using any output devices for the waste before it is dried.

The invention is illustrated more in detail here below in connec¬ tion with the attached drawings, schematically showing two embo¬ diments as examples of means according to the invention, and where figure 1 is a schematic vertical section of a first embodi¬ ment and figures 2, 3 and 4 are schematic vertical sections of a second embodiment illustrating three different steps of treat¬ ment.

Figure 1 shows a feeding hopper 1 with a sealingly closable cover 2 arranged on top of a vertical, cylindrical chamber 3. In the top thereof a pulverizing means 4 is arranged, in which the waste is pulverized and falls down into the dewatering means below in form of a centrifuge 5. Under it there is a device 6 for blowing in hot drying air. After the material has been dried in the cent¬ rifuge 5 it is descending in the air stream and the last material is scraped off, the centrifuge having slowed down. The device 6 is then lowered a bit so that the dry pulverized waste can descend into a collecting container 7. Fluid is leaving the cent¬ rifuge 5 through a pipe 8 and air having created a vacuum in the means is leaving through a pipe line 9.

The means has a simple design without any unnecessary material transfer devices, but with a at the same time limited capacity. An essentially increased capacity and a shorter treating period is illustrated by a means according to figures 2-4.

Also this means has a feeding hopper 21 with a sealingly closable cover 22 on top of a vertical, cylindrical chamber 23. In this chamber a mill 24 is situated with an around a horisontal shaft rotatable rotor with radially protruding fingers 26. Furthermore, the mill comprises a stationary arranged, horisontal screen 27, through the spaces of which the rotor fingers 26 are adapted to pass during their descending movement, as well as a in a semi¬ circle bent, perforated bottom plate 28, along which th- ends of

the rotor fingers 26 are passing with little space in between. Under it a collecting hopper 29 is fastened, at the bottom of which an opening 30 is arranged, to which a pipe line 31 is con¬ nected. This line is bending uppwards and at its lowest part a draining pipe line 33 for fluid is connected, equipped with a valve 32. The upwards bending part of the pipe line 31 is split¬ ting into two branches 35 and 36 at the two-way valve 34. The branch 35 comprises an electrical air heating device 37 and an outlet valve 38 and is connected to the pressure side of a fan 39. The other branch 36 leads to a cyclone 40 for separating the material transported by an air stream from the air stream itself, this air escaping through a pipe line 41 into the suction side 42 of the fan 39. Furthermore, the pipe line 41 is supplied with a closing valve 43 for eventually sending air to the suction side 42 of the fan 39.

The means according to the figures 2-4 performs as follows. Ac¬ cording to figure 1 the waste 44 is fed through the open cover 22, thereby descending into the chamber 23, in which the rotor 26 i slowly rotating and is pressing the waste through the screen 27. Fluid 45 is pressed out of the waste and is dripping and flo¬ wing through the perforated bottom plate 28 down into the pipe 31 and out through the open valve 32 into the pipe line 33. When the chamber 23 is sufficiently filled, the cover 22 is closed and the fan starts, sucking air from the outside through the valve 43 and blowing the air through the heating device 37, being connected to the net and heating the passing air in accordance with figure 3. The heated air passes the valve 34 and is led past the closed outlet valve 32 to the chamber 23 via the holes in the bottom plate 28. The rotor 26 is still rotating slowly so that the waste is lifted and is exposed to the hot drying air, escaping through two pipes 46. At the screen 27 larger parts of the waste are devided bit by bit and smaller parts being created will float and whirl around in the air stream, becoming drier and drier. Some parts of the pulverized material are falling through the holes in the bottom plate 28 and are performing a fluidized bed in the conical collecting hopper 29. All waste being completely dewate- red and dry, the heating device 37 is turned off and the valve 34

is reversed so that the suction side 42 of the fan 39 is connec¬ ted to the pipe line 31 in accordance with figure 4. At the same time valve 43 is closed and valve 38 is opened so that the air being sucked in through the pipes 46 and passing the ch aber 23, the pipe line 31 and the cyclone 40 can escape through valve 38. Thereafter, the rotational speed of the rotor 26 is substantially increased and is starting a sluice outlet 47 at the bottom of the cyclone 40. Waste particles having passed the about 3 mm large holes in the bottom plate 28 are pulled forward by the air stream and are separated from it in the cyclone 40, where the air esca¬ pes to the suction side 42 of the fan and the waste particles are in a conventional way pushed out through the sluice outlet 47. Waste particles in the chamber 23 being too large to pass the holes in the bottom plate 28 are crushed against the screen 27 becoming sufficiently small to be sucked away.

The rotor and its fingers or branches 26 and the screen 27 as well as the perforated bottom plate 28 are arranged for an easy exchange to be shifted after a wear down or for an adaption to a coarser or a finer grinding of the dried waste particles.

Tests have shown that waste treated in this way can be stored for any amount of time without any sanitary inconvenience. It can be used as animal food under the condition that no inconvenient waste products are comprised or as a soil improvement means or as a fuel.

The means can be adapted to bungalow and flat kitchens, an exemp¬ tion probably being avai-able from the health authorities for waste collection only e.g. each second or each third week instead of each week, being the normal procedure. As one can see this means large savings.

By connecting the chamber 3 and 23 respectively to an extra eva¬ cuating fan during the waste drying a vacuum can be sustained at all times in the chamber.