Note: Descriptions are shown in the official language in which they were submitted.
7E~73 "
This invention relates to an asphalt recycle system.
Conventional asphalt used for pavement works is normally thrown away
as waste during road repairs. ~owever, such disposal of asphalt waste invites
not only economical loss but also environmental pollution. Furthermore, the
transportation of the waste consumes considerable time and cost. It is also
unfavored from the standpoint of utilizing resources which is presently a
world-wide problem.
Hence, a system which recycles asphalt has been searched for. The
recycling or regenerative methods proposed in the past include that of heating
the waste with high-frequency waves or directly with flame; that of exposing
the wastetO steam; that of indirectly heating the waste with high-temperature
oil; and that of crushing. None of these methods, however are commercially
satisfactory~ for various reasons such as expense or qualitative degradation.
The present invention attempts to provide an asphalt recycle system
of high practicability which can maintain the asphalt at the high quality
level.
In a preferred system according to the invention, steam is supplied
into water to regenerate the heretofore thrown away asphalt waste, and remark-
ably improved treating effects are achievedO To wit, one of the essential
features of the present invention resides in jetting steam into water, whereby
the asphalt waste is heated in the presence of water.
According to the invention, the asphalt waste is sunk in water during
both the heating and the separation (decomposition)~ This is an important
feature of the invention. Use of steam also is an important feature, but it
can achieve the desired effect only when used in combination with the water.
. .
; Therefore, the system is based on a fundamentally different principle from
that of the recycle system in which the waste is heated when exposecl to an
atmosphere of steam. Again, while various heating media are known, high-
temperature steam is used in the invention to heat the asphalt waste in water.
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According to the present invention, there is provided a method o
regenerating asphalt waste, comprising the steps of: jetting steam into water
in a tank to make said water hot; sinking asphalt waste into said hot water in
4 said tank; heating said asphalt waste in said water to a predetermined temp-
erature level to make said asphalt waste soft; and separating said heato~ and
softened asphalt waste as sunk in said water by means of a mechanical separator
thereby to make said asphalt waste disengaged into aggregate grains or elements
each having the surfaces coated with a thin asphalt film
In another aspect, the present invention provides an apparatus for
regenerating asphalt waste, comprising: a tank for containing water to a
predeterm~ned level; means for jetting steam into water in said tank to heat
the water; and means for mechanically separating in the water the asphalt
waste as heated and softened by the steam.
- The method of this invention permits the asphalt waste, when torn
off from a paved road, to be treated. In other words, sorting or washing of
the waste pieces is unnecessary. This is a great advantage in practicing the
method. If a preliminaYy sorting or washing of the material is required
` before the regenerative treatment~ particularly when enormous volume of the
waste is to be treated, the time and cost loss would be very serious.
Again according to the invention, because the asphalt waste is de-
composed (separated) as softened and sunk in the water, the aggregate does
not adhere to the separation tank or to other aggregates.
.
Furthermore, the separation (decomposition) of the asphalt waste as
softened and sunk in the water produces another advantage that the individual
aggregate grains are simply separated among one another~ but an aggregate
grain itself is not brokon. This i~ very important, particularly in rolation
to the strength. As is well known, the shape or configuration of the aggregate
is an important factor in obtaining the predetermined strength of asphalt
concrete. For this reason an asphalt ~e y~le system which destroys the
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aggregates, such as the crushing method, carmot be said practical. According
to the invention the aggregates are simply separated into individual pieces
while retaining the original shapes, and is free of the problem of strength
- deterioration.
The present invention will now be described in more detail with
reference to the accompanying drawings, in which:-
Figure 1 is a schematic vertical section of an asphalt recyclesystem according to the present invention;
Figure 2 is a diagrammatic view of another asphalt recycle system
according to the present inven~ion;
; Figure 3 is a schematic vertical section of a part of the asphalt
recycle system shown in Figure 2,
Figure 4 is a schematic view of still another asphalt recycle system
according to the present invention; and
Figure ~ is a side view of the system shown in Figure 4.
According to the invention~ first the heated steam is jetted into
water in a tank, and into which the asphalt waste is sunk and heated to a
predetermined temperature. Normally preferred temperature level of the waste
ranges from 80 C to 100 C under the atmospheric pressure, particularly approx-
- 20 imately 90 C. Obviously the temperature condition is variable under highly
pressuri~ed atmosphere or under other unusual ambient conditions. Thus heated
asphalt waste is separated by a suitable mechanical means as sunk in the water.
.,
For example, the asphalt waste is sunk in the water in the tank and heated at
- 100 C for approximately 20 minutes, and disengaged into individual
,
grains in the water by means of, for example, a screw.
The mixture resulting from the separation according to the invention
.
; consists of many aggregate grains each having the surfaces coated with a thin
asphalt film. The sizes of the aggregates depend on those of the asphalt was~e
~ initially introdwced to the water. They may be uniform or various. The
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- asphalt coating on the surfaces oE a grain of the asphalt waste possesses
strong adhering power to that particular grain, but exhibits no adhering
tendency to other aggregate grains or the asphalt coating on their surfaces.
Therefore, the great number of aggregate grains each having the asphalt-coated
surfaces are loose and mobile independently of each other. Consequently, they
can be very easily sorted with sieves into the desired number of size groups
if necessary.
- The asphalt coating on the aggregates' surfaces may contain a minor
amount of an active substance. Preferably the amount of such an active sub-
` 10 stance should range 5 to 20 % to the asphalt coating by weight ratio, inter
~` alia, approximately 10 %. (The ratio may be varied depending on the intended
utility-of the product, type and dimensions of the aggregate, specific type
- of the asphalt, etc.) While various active substances may be used, preferably
` active terra alba and active carbon are concurrently employed. It has been
experimentally confirmed that favorable results can be obtained when the active
` component is composed of approximately 80 - 95 % of active terra alba and
approximately 20 - 5 % of active carbon. Optimum results can be obtained,
furthermore, when 90 % of active terra alba and 10 % of active carbon are
used, although the results are to some extent dependent also on other condi-
;~ 20 tions of use.
The asphalt coating may furthermore contain filler. The suitable
filler content is widely variable depending on the intended utility of the
product, but normally it is preferable to use approximately the same amount
offfiller to that of the asphalt.
~: The mixture of the asphalt-coated aggregates of various grain sizes
can be put to various usages as it is, but the field of its application can
be still broadened when it is sorted into groups of approximately same grain
sizes. For instance, the mixture may be diviclccl with sieves ;nto four size
groups to be put to four separate usages as follows:
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(a) the grains having the diameters ranging from 20 mm to 13 mm; ~b) those
of 13 mm to 5 mm; (c) those of 5 mm to 2.5 mm; and (d) those having the
diameters less than ~.5 mm. It is also possible to blend the aggregates of
those size groups at a suitable blend ratio.
~lereinafter some of the embodiments of this inven~ion will be ex-
plained with reference to the attached drawings.
` First referring to Figure 1, a sheet of wire net 5, steam pipe 3,
and a crusher or separator 6 are installed inside a tank 4 at sequentially
lower position, by the order stated. The wire net 5 and the crusher or
separator 6 may be omitted if so-desired. At the bottom of the tank 4, a means
of transportation, for example, screw 8, is connected. The screw 8 can func-
tion also as the means for separation, and therefore the asphalt can be suf-
ficiently separated without the crusher or separator 6. The screw 8 is also
connected to the lower edge of a hot elevator 9. A means for selection or
sorting, for example, a shaking sieve 11, is located at the position to receive
` the asphalt waste dropped from the upper end of the elevator 9. The sieve ll
is provided with the sorting pipes 13. The steam pipes 2 from the boiler 1
are connected respectively to the tank 4, hot elevator 9 and the screw 8, each
containing as installed therein a porous steam pipe 3. The tank 4 and the hot
elevator 9 are filled with water to the predetermined level X. Into the water
;- in the tank 4, heated steam is jetted through the pores in the steam pipe 3.
The operation of the above-described apparatus according to the
; invention will now be explained.
Blocks of asphalt waste 15 are thrown into the tank 4 from the
,` top, which can be efficiently accomplished with a shoveldozer. The blocks
.; are first roughly sorted with the wire net 5. In the embodiment illustrated
`:
'~ by Figure 1, the water level X in the tank 4 is set above the wire net 5.
Heated steam is jetted into the water in tank ~ ~rom thc boilor 1, through the
steam pipes 2 and 3, to raise the temperature of the system to an appropriate
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113~7~73
level, -for example, 90C. Thus heated asphalt waste is separated into the
h~r ~ c~-f~
r~i aggregates with the ~n~r 6 and/or screw 8. Thus separated aggregates are
~ sent to the shaking sieve 11 by means of the hot elevator 9 where the aggregate
are sorted into the desired number of groups according to their grain sizes.
Thus separated and sorted aggregates are mixed with a volatile
liquid and an emulsifier to provide regenerated asphalt blocks (room tempera-
ture asphalt blocks). It is also possible to obtain a regenerated asphalt
mixture by heating the sorted aggregates. Thus the asphalt waste can be re-
- generated and re-used for the conventional road-paving.
Now another embodiment of the asphalt waste recycle system according
to the invention will be explained, referring to Figures 2 and 3O
Although two tanks 10 and 12 are shown in Figure 2, the number of
tanks is optional. That is, a single tank or more than two tanks may be used
depending upon particular needs. The tanks 10 and 12 are connected to the
hot elevator 143 the other end of the ele~ator 14 leading to a screen sheet
160 The tanks 10 and 12 are also connected to a driving source 18 which is
controlled by the regulating means 20. The tank 10 is connected to a boiler
~ 2~ so that a high-pressure and high-temperature steam may be sent into the
: tank. Similarly the tank 12 is connected to the boiler 22 for sending a
high-pressure and high-temperature steam. The boilers may be combined into
" one.
The important features of the above-described construction will be
explained in further detail with reference to Figure 3O The boiler 22 is
provided with a plurality of pipes 26, a part of which are connected to the
hot elevator 14, and another part to the inside of thc ~ank 12. The pipe 26a
in the tank 12 is perforatod, and through tho many poros hoated stoam is
jetted into the water~ At the bottom of tank 12 a separation mcilns 28 is
installed. The separation means 28 used in the em`bodiMent is of screw type7
and the separation is effected as the materia~L under treatment moves from the
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left to right in the drawing. The tank 12 is filled with water 30 to the
level X. The hot elevator 14 is connected to the tank 12 by the pipe 260
The water level X is common between the tank 12 and hot eleva~or 1~. From
above the tank 12 the asphalt waste blocks are thrown into the ~ank and heat-
ed to the predetermined temperature in the high-temperature water. The blocks
are then transferred to the right direction while being disengaged into in-
dividual aggregate grains by the action of screw 28. Thus separated, aggre-
gates are sent upward by the hot elevator 14 and further transferred into the
sorting means 16 (for example, screen) to be sorted into size groups.
In this embodiment also the suitable temperature of water ranges
from 80 C. to 100 C., particularly about 90 C. (The temperature is variable
under special ambient conditions such as highly elevated pressure).
Incidentally the separation means 28 is not limited to the screw
type. The sorting or screening means 1~ is preferably so designed that it
can sort the aggregate grains into four groups according to their diameters,
, respectively ranging (a) 20 mm - 13 mm (b) 13 mm - 5 rnm (c) 5 mm - 205 mm and
(d~ less than 2.5 mm. ObviOuslyg sorting in different manner is perfectly
acceptable as the occasion demandsO
` Referring back to Figure 27 each of the size groups sorted by the
screening means 16 (to wit, the aggregate grains each having the surfaces
~ coated with an asphalt film which exhibits no adhesivenessto each other) is
: sent to the respective feeder hopper. For example, the grains of the diameters
ranging from 20 mm to 13 mm are sent to the feeder hopper 320 Those of the
` diameters ranging from 13 mm to 5 mm are sent into the feeder hopper 34;
those of 5 mm to 2.5 mm, to the feeder hopper 36; and those of less than 2.5
mmg to the feeder hopper 3~0 Similarly, the feeder hoppers 40, 42, 44 and 46
.
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- are provided to collect the aggregate grains of the diameters, respectively,
;~:
ranging from 20 mm - 13 mm~ 13 mm - 5 mm~ 5 mm - 2.5 mm~ and lcss than 2~5 mm.
The feeder hoppers 32~ 34, 36 and 3~ are provided with a conveyor 41 in common,
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which is movable to either right or left 'by the signa:L given by the controlling
means 20. The conveyor 41 is also connected to a reserve feeder hopper 42
which is to accommodate any suitable mixture. Obviously~ more than one reserve
feeder hopper may be installed if necessary. At one end of the conveyor 41~
a room-temperature dry asphalt blending means 43 is installed, which is fur-
ther connected to a room-temperature pug mill mixer 48 through the conveyor 45.
The mixer 48 in turn is connected to a room-temperature asphalt storing means
52, through the conveyor 50. Any desired amount of the room-temperature
asphalt can be suitably taken out of the storing means 52 as the occasion
demands. On the other hand, a various heating dry asphalt blending means 54
.
is located at the other end of the conveyor 41. The dry asphalt blending
'; means 54 is connected to a dry mixer 58 through a conveyor 56, and the dry
mixer 58 is connected to a surge tank 62 through a conveyor 60. The heating
asphalt mixture can be suitably taken out of the surge tank 62 as the occasion
:~ demands. The aggregate of the grain sizes greater than 20 mm is wi~hdrawn to
the direction of the arrow marked 64.
Furthermore, the feeder hoppers 32, 34, 36 and 38 are each provided
with a valve, respectively, 32a, 34a, 36a and 38a. By controlling those valves
with the controlling means 20, the blend ratio of the asphalt mixture can be
; 20 freely selected. Also the feeder hoppers 40, 42, 44 and 46 can provide each
the asphalt mixture of uniform grain size, and have the valves 40a - 46a.
'~ A still another embodiment of the invention will now be explained
with reference to Figures 4 and 5.
A mobile chassis 10 has wheels 12. In the illustrated embodiment,
the system is run as a motor truck, the driver's seat being positioned at
the left side. If required, however, the 'base lO may be separated from the
` driver's seat or the driving portion by employing a trailer system or any
other suita'ble system,
The treating tank 14 is mounted on the base lO, which is so eonstructed
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that it can contain water to a predetermined level. At the lower portion of
the tank 14 a separation means 16 is provided. The specific type of the
separation means 16 is not critical, but in the embodiment shown, a screw
system is employed. The separation means 16 is connected to a transportation
means 18 which is a bucket-type elevator in the embodiment shown. The
transportation means 18 is extended from the position of the separation means
16 to that above the treating tank 14, disposed with a slight inclination.
The transportation means 18 is driven by the motor 20. A sorting means 22 is
loc~ted at the forward end of the transportation means 18.
The treating tank 14 is connected to a boiler 24 through the pipe
26 as shown in Figure 4, so that the water in the tank 14 is filled to the pre~
determined level is heated to the predetermined temperature by the steam
jetted thereinto from the boiler 24. The type of the boiler 24 is not critical~
and the ~oiler itself is not novel. Hence, no detailed explanation of the
boiler will be given.
The top of the treatment tank 14 has an opening 14a, which allows the
entrance of the asphalt waste to be treated. Obviously, optional design change
such as closing the top and providing an entrance at other portion of the
tank, is perfectly allowable.
In the embodiment shown, the top of the treating tank 14 is opened as
aforesaid~ and the asphalt waste blocks are lifted up to the opening 14a by the
elevator 28, to be automatically dropped into the water in the tank. If the
elevator 28 is not used~ the asphalt waste 410cks may be directly thrown into
the tank from the opening 14a by other means, for example, a shovel-dozer. The
asphalt mixture to be treated is placed in the tank 14, and heated to the pre-
determined temperature by the water which has been heated to aLso the predeter-
mined temperature by the jetted steam stream from the boiLer 24. The asphalt
:::
mixture thus sof~ened by the heating i3 disengaged by the separation means
16, while moving leftward (in the drawing). After the separating treatment,
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the disengaged aggregate grains are sent to the sorting means 22 by the trans-
portation means 18.
~ n example of the sorting means 22 will now be explained more specifi-
cally. In the embodiment shown, a shaking screen is used as the sorting means
22~ The screen sieve is shaken as driven by the motor 30 and simultaneously
moved from the right to left in the drawing, whereby sorting the material
under treatment. In the specific embodiment, the material is sorted into four
groups according to ~he grain si3es. Below the sorting means 24, four guide
members 32, 34~ 36 and 38 are disposed to guide, respectively, the grains of
the diameters ranging from 20 mm to 13 mm, from 13 mm to 5 ~m, from 5 mm to
2.5 mm, and less than 2.5 mm. The guide members 32, 34, 36 and 38 are provided
respectively with the valves 32a, 34a, 36a, and 38a. By the suitable valve
` control the blend ratio of the asphalt mixture can be varied as desired.
Also the three guide members 34, 36 and 38 are combined into one by the guide
member 40. Incidentally, 32b is the exit from the guide member 32~ and 40a~
the exit from the guide member 40.
- The base 12 is furthermore provided with the power source 42, water
- tank 44, and a fuel tank 46. The power source 42 is to drive the necessary
motors, and for this purpose is connected to the motor 30 and motor 48 (for
driving the separation means 16). The water tank 44 is connected to the
boiler 24 through the pipe 50, aS well as to the treating tank 14. The fuel
tank 46 is installed to supply fuel to run the boiler 24.
The aforedescribed parts may be manually handled, but in the shown
embodiment they are automatically operated by the control device 52. The
connection chart of the control device 52 and the individual parts is nok
shown, but all the connections are eloctrica:l:Ly secured. ObviousLy, it is
allowable to run some parts `by automatic control and the rest, by manual
;:
handling. It is le~t optional to the user's choice. A valve 26a and 50a is
provided on pipe 26, and pipe 50 respectively.
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