[0001] It is known that the apparatuses for recycling asphalt are largely formed of coaxial
cylinders that have in their inside two separated chambers: the drying chamber and,
in the bigger cylinder, the combustion chamber. The axis of the coaxial cylinders,
such as the plant accessorial elements, are angled of some degrees in comparison with
the horizontal line to permit to the material flow in working inside the cylinders
to move itself in the slope direction. Moreover, the drying chamber is in rotation
to favour the heating and the mixing of the inert materials and of the recycling material
introduced from the top in the plant. With the words recycling material is meant the
materials coming to the demolition of previous wearing courses, introduced inside
the bigger cylinder to an upper opening. Moreover the combustion chamber has at its
inside a burner placed downstairs of the plant that, in central area, generates a
flame so to heat the introduced materials. The heating of the materials till the compound
formation downstairs of the plant is necessary to have the fluid vein of the melted
inert materials and melted recycled materials. The aggregate of bitumen with the recycled
material determines, after to be positioned onto the street in construction and by
use of other engines, the new wearing course. The invented apparatus consists of a
particular orifice plate, separating the combustion chamber to the drying chamber
and the other components, able to increase the plant productivity and also to permit
the use of bigger quantity of recycled material with consequent decrease of the costs
of the actuated new wearing course. The apparatus is so able to use bigger quantity
of material to be worked and to have a large adaptability to the necessities of the
different asphalting engines. The invented apparatus consists of an orifice place
1 separating the combustion chamber 2 to the drying chamber 3 of any kind of plant
4 to recycle the asphalt with production, at the end, of inert materials and recycled
materials mixed for the bituminous conglomerate plants. Said orifice plate 1 equipped,
onto the ledging part to the burner flame, of fixing elements 5 able to permit the
assembling of one or more affixing structures 6, in truncated cone shape or in shape
of nozzle, in shape continuity with the same orifice plate 1 and so to help the slippage
of the air flow passing inside. Moreover onto the outside conical part of the orifice
plate 1 and of the structures 6 are present ledges 6A with angle of about 45° in comparison
with the longitudinal axis so to direct the flow of the recycled materials and to
permit its falling, with the rotation given to other parts connected to the affixing
structures 6 and to the orifice plate 1, in parts of the combustion chamber not under
the orifice plate 1 and the structure 6. Said structures 6, to be added to the plant
on the base of the production necessities, have an opening toward the burner flame
that comes to tighten on the base of the number and/or dimension of the elements of
the affixing structure 6. The truncate cone structures 6 added to the orifice plate
1 are so to realize a restriction of the air flow placed through the burner and the
outlet given to the stack 7. The air flow passes from the drying chamber 3 to the
combustion chamber 2 crossing the central opening 8 of the affixing structures 6 and
coming to form, in relation to the actuated restriction, a Venturi effect before coming
inside the combustion chamber 2. It is to consider that the affixing structures 6
permit to extend the conicity in the requested dimension for bigger quantity of working
material also maintaining unchanged the other parts of the plants. Infact, having
actuated the central opening 8 more narrow, the air flow inside the plant is accelerated.
So coming air more quickly is increased also the oxygen quantity presents in the combustion
chamber and the flame, generated to the burner, reaches higher temperatures. The higher
temperature inside the combustion chamber permits an use of bigger quantity of recycled
material so like an increasing of the plant productivity. The affixing structure 6,
connected to the orifice plate 1 by the fixing elements 5, are so provided in numbers
and dimensions in relation to the plant productive capacity wanted, considering the
increasing of the air flow on the base of the product quantity wanted and the end
of the same plant. The orifice plate 1 and the affixing structure or structures 6
are put in rotation such as they are connected with the drying chamber 3 puts in movement
by outside motors. Moreover, the orifice plate 1 has on its level border, placed previous
the truncate cone ledging structure or ogival one, of openings 9 to permit the air
passage at high temperatures from the combustion chamber 2 to the drying chamber 3.
Said openings 9, realized boring the structure long the vertical wall 10, have an
important rule such as, since in combustion chamber there is a considerable increasing
of the temperature with relative increasing of the pressure, said openings 9 permit,
through the air flow with opposite direction in comparison with the central one that
goes to feed the burner flame, to bring air and smokes with high temperature to the
drying chamber. Moreover, said air and said smokes, passing through the openings 9
placed onto the metallic structure of the truncate cone orifice plate 1, heat the
same structure brings the same to a high temperature. The recycling material, coming
to the inlet hopper 11 placed over the combustion chamber, infact, tends to attach
to the outside surface 12 of the orifice plate 1 and to the outside surface of the
affixing structures 6 if these parts are not at high temperature. It is to consider
that the material coming to the hopper 11 and that falling down for gravity inside
the combustion chamber 2, if it comes to attach to the walls of the outside surface
12, generates stoppage and it limits the inlet carrying of the material. The openings
9 so permit to have the orifice plate 1, the elements 10 and 12 and the affixing structures
6 with high temperature in the particular parts so avoiding the adhesion of the worked
recycling material. It is to be noted that the hopper 11 is placed in correspondence
of the orifice plate 1 so that the ledging part of said orifice plate avoids the direct
radiation of the flame onto in inlet material which will determine the material fusion
in the inlet hole and so stoppage to the hopper and to the underlying parts. The hopper
11 in this position permits, moreover, to have more time for the drying of the inert
materials coming to the chamber 3 and to mix in more homogeneous way the recycled
materials with the inert materials. Infact, the hopper disposition in this position
permits to better eliminate the humidity in these materials when these are melted
to the high temperatures create and to the more time of remaining inside the combustion
chamber. Then, complementary, inside the drying chamber 3, i.e. inside the rotating
drum put in movement to the motors 13, are present suitable tongues 14 to spread the
inert materials which fall down to the cavities 15 placed inside the rotating drum.
The drying chamber, infact, rotates around the own axis longitudinally bringing to
a fixed distributor the material that comes inside of longitudinal cavities 15 placed
in parallel long the own inside surface. At a determined height the contents of said
cavities, i.e. the inert materials, fall in the low part of the rotating drum. During
the falling the poured material to the cavities 15 meets the tongue 14 that spreads
the inert material forming a thin layer of material inside the cylinder forming the
drying chamber 3. The material spread in the falling flow from the upper part of the
rotating drum to the tongue 14 better holds the hot smokes inside the drying chamber
and in the same time the material placed in rotation and poured is heating. Moreover,
to facilitate the drying and to eliminate the humidity dangerous to the formation
of the bituminous conglomerate and to extend the permanence time inside the apparatus,
in the inside part of the combustion chamber, also this in rotation in this part,
are placed crowds of tongues 16, perpendicular to the inside surface of the rotating
drum and placed with incidence angle long the material flow direction so to slow the
flow same. The surface of these tongues that meet the flow is, infact, angulated in
such a way to bring again at the beginning of the plant the elements forming the material
of new emission and of bigger dimension. Said elements of bigger dimension heavier
are pushed in contrary direction to the flow directs to the end of the plant by the
surface of the tongues and increase their time of permanence inside the plant. Moreover,
the new emission material parts are often those with bigger humidity containment.
The function of the tongues 16 is so that to increase the permanence time and, such
as those tongues 16 are in projection from the inside surface of the rotating drum,
they bring those parts of new emission material in surface in comparison to the flow
material that flows inside of the inner concavities of the cylinders, whereas the
material goes on toward the outlet at the end of the plant, from the part of the burner.
The invented apparatus is illustrated in a merely indicative and not limiting way
in the drawings of sheets 1, 2 and 3. In sheet 1 figure 1 is longitudinal section
view of a plant to dry inert materials, to recycle asphalt and to produce with other
mixing machineries bituminous conglomerates. In sheet 2 figure 2 is section view of
the invented apparatus. Figure 3 is lateral view of the same apparatus. In sheet 3
figure 4 is inside view of the tongues placed into the rotating drum to spread the
inert material produced inside the plant. Figure 5 is perspective view of the tongue
14 with cavity 15 carrying the material. The figure 6 is section view showing the
tongues 16 angulated in comparison to the material flow coming down to the plant.
