JP2607020Y2 - Aggregate heating and drying equipment in asphalt plant - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for heating and drying aggregate in an asphalt plant for producing asphalt mixture, and more particularly to a technique for efficiently drying and drying coarse aggregate in a dryer.

[0002]

2. Description of the Related Art Conventionally, asphalt mixture for pavement etc.
It is manufactured as follows. That is, the liquid asphalt is stored in a heated state, and is sprayed into the mixer after the measurement. Aggregate which is a solid material is sent to a dryer and dried by heating. The heat-dried aggregate is put into a screen, sieved, and stored according to particle size. After the stored aggregate is weighed, it is put into the mixer and mixed with the liquid asphalt and stone powder to produce an asphalt mixture.

[0003] In recent years, as the asphalt mixture, the use of open-particle mixtures having water permeability that is advantageous from the viewpoint of traffic safety, environmental measures and the like has been increasing.

[0004]

However, in the manufacturing process, there is a problem that the heat-drying property is poor and the production capacity in an asphalt plant is reduced. That is, the specific surface area of the coarse aggregate is smaller than that of the fine aggregate, and the coarse aggregate is generally harder to dry than the fine aggregate. The amount of the opened granulated material is as small as about 20% as compared with a normal mixed material in which the mixing ratio of the fine aggregate is about 50%, and as a result, it is difficult to dry.

[0005] Heat drying of aggregates in a dryer is performed by using all of convection, radiation and conduction, which are the three elements of heat transfer. Since there is little aggregate, there is little conduction heating for wrapping and heating the coarse aggregate with fine aggregate that tends to rise in temperature, and the heat drying ability is low. In view of the above conventional problems, the present invention aims to improve the production capacity by efficiently heating and drying coarse aggregate in a dryer in an asphalt plant for producing asphalt mixture. Aim.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention provides an aggregate heating and drying apparatus for heating and drying an aggregate as a material of an asphalt mixture in an asphalt plant for producing an asphalt mixture. A dryer for heating and drying the supplied aggregate, a screen for sieving the heat-dried aggregate by particle size, and a chute for collecting excess fine aggregate among the sieved fine aggregate, and A surge bin for storing surplus fine aggregate, a supply device for supplying the other sieved aggregate to a process after sieving, and a constant amount of fine aggregate stored in the surge bin for supplying to the dryer And a step of repeatedly supplying a surplus fine aggregate stored in the surge bin to the dryer together with the aggregate to be heated and dried.

[0007]

In such a configuration, the aggregate, which is a solid material, is sent to the dryer. The aggregate is heated and dried by a dryer. The heat-dried aggregate is put into a screen and sieved. The surplus of the sieved fine aggregate, that is, the overflow, is collected by a chute, stored in a surge bin via the chute, and the other aggregate is supplied to a process after the sieving by a supply device. .

[0008] A certain amount of surplus fine aggregate stored in the hot bin is supplied to a dryer together with the aggregate to be heated and dried by a feeder. As described above, after supplying the aggregate to the dryer and drying by heating, sieving according to particle size, collecting and storing excess fine aggregate of the sieved fine aggregate and other aggregates Is supplied to the step after sieving, and the step of supplying the stored excess fine aggregate to the dryer together with the aggregate to be dried by heating is repeatedly performed, and the excess fine aggregate is circulated to the dryer. Thereby, the heat drying property of the coarse aggregate in the dryer can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a configuration of an asphalt plant to which an embodiment of an aggregate heating and drying apparatus of the present invention is applied. In this figure, an asphalt tank 1 for storing liquid asphalt in a heated state is provided, and an asphalt measuring hopper 3 for transferring liquid asphalt stored in the asphalt tank 1 through a pipe 2 is provided. Further, a mixer 4 for spraying the liquid asphalt measured by the asphalt measuring hopper 3 is provided.

On the other hand, there are provided a cold hopper 5 to which an aggregate as a solid material is supplied, and a feeder 6 for cutting the aggregate from the cold hopper 5. Further, dryer conveyor belt conveyors 7A and 7B for conveying the aggregate cut out by the feeder 6 are provided.
A dryer 8 for heating and drying the aggregate conveyed by A and 7B is provided.

The dryer 8 is formed in a cylindrical shape, and is disposed at an angle. A hot elevator 9 for conveying the aggregate heated and dried by the dryer 8 vertically upward is provided, and a screen 10 on which the aggregate conveyed by the hot elevator 9 is supplied is provided. The screen 10 is for sieving aggregate according to particle size, and is formed in a multilayer shape of 4 to 5 layers. This screen 1
The mixers 4 are disposed below the mixers 0, and between the screens 10 and the mixers 4, hot bins 11, 1 for storing aggregates sieved by the screens 10 according to the particle size, respectively.
1A and an aggregate weighing hopper 12 are provided. The hot bins 11 and 11A are partitioned into 4 to 5 locations according to particle size. Incidentally, the steps after the sieving of the aggregate by the hot bins 11 and 11A and the aggregate weighing hopper 12 (mixer 4)
Is provided.

Here, a chute 13 for collecting surplus fine aggregate from the aggregate sieved by the screen 10 is used.
And a surge bin 14 for storing the collected excess fine aggregate.
And a feeder 15 for supplying a certain amount of fine aggregate stored in the surge bin 14 to the dryer 8. Sampling port 13 formed at the upper end of the chute 13
a is opened at the position of the upper surface opening of the hot bin 11a for fine aggregate having the finest particle size.

A circulating belt conveyor 16A and a circulating belt conveyor 16A are provided between the feeder 15 and the dryer feeding belt conveyor 7B.
16B are provided. Next, the operation and effect of the embodiment of the aggregate heating and drying apparatus of the present invention will be described while explaining the operation of the asphalt plant having such a configuration. The liquid asphalt is stored in a heated state in the asphalt tank 1, transferred to the asphalt measuring hopper 3 through the pipe 2, and sprayed into the mixer 4 after measuring.

On the other hand, the aggregate, which is a solid material, is cut out from the cold hopper 5 via the feeder 6, and is sent to the dryer 8 by the dryer feeding belt conveyors 7A and 7B. In this case, the aggregate is supplied in a predetermined amount that becomes a predetermined mixture ratio, but the fine aggregate of the aggregate is supplied in an amount equal to or more than the predetermined mixture ratio. The aggregate is heated and dried by the dryer 8. The heat-dried aggregate is transported to the screen 10 by the hot elevator 9 and the screen 1
0, sieved, hot bottle 11, 11A
Are stored according to particle size.

The surplus of the sieved fine aggregate,
That is, the overflow is collected by the chute 13 in the hot bin 11A, and stored in the surge bin 14 via the chute 13. The hot bin 11, 11A
Aggregates stored by particle size are weighed by an aggregate weighing hopper 12, and then charged into the mixer 4, where they are mixed with the liquid asphalt and stone powder to produce an asphalt mixture.

A certain amount of the surplus fine aggregate stored in the surge bin 14 is supplied to a circulating belt conveyor 16A, 16B by a feeder 15, and the conveyor 16A,
From 16B, it is supplied to the dryer conveyor belt 7B and supplied to the dryer 8 together with the aggregate to be heated and dried. As described above, after the aggregate is supplied to the dryer 8 and dried by heating, the aggregate is sieved according to particle size, the surplus fine aggregate is collected from the sieved aggregate, stored, and other aggregates are collected. The process of supplying the excess fine aggregate stored in the process after the sieving and storing the excess fine aggregate together with the aggregate to be dried by heating is repeatedly performed.

In this case, at the beginning of the operation, as described above, the fine aggregate to be charged into the dryer 8 is fed in an amount equal to or higher than the mixing ratio until overflowing in the hot bin, and thereafter, the fine aggregate to be charged into the dryer 8 is mixed. Return to the amount suitable for. As a result, fine aggregate in an amount equal to or greater than the mixing ratio is always supplied to the hot bottle 11A, and the excess amount
3 and stored in the surge bin 14.

If the amount of fine aggregate stored in the surge bin 14 is excessive or deficient, the amount of fine aggregate supplied by the feeder 6 is controlled according to the excess or deficiency. in this case,
The surge bin 14 has a sensor 1 for detecting the storage amount of fine aggregate.
7 is provided, and is configured to control the feeder 6 according to the storage amount detected by the sensor 17.

According to the aggregate heating and drying apparatus described above,
After supplying the aggregate to the dryer 8 and drying by heating, the aggregate is sieved by the screen 10 according to the particle size, and the surplus fine aggregate of the sieved aggregate is collected by the chute 13 and stored in the surge bin 14, As a result of repeating the process of supplying the stored excess fine aggregate together with the aggregate to be heated and dried to the dryer 8, the heat dried excess fine aggregate is circulated to the dryer 8, The heat drying property of the coarse aggregate in the dryer 8 can be improved.

Therefore, the heat drying ability is high even when a small amount of open aggregate of about 20% is used as compared with a normal mixture in which the blending ratio of fine aggregate is about 50%. Thus, the production capacity of the asphalt plant can be improved. That is, when producing a normally open mix, there is only a drying capacity of about 60% of the nominal capacity of the plant,
By circulating the fine aggregate as described above, a capacity of 90
% And fuel economy can be saved.

In particular, according to the above aggregate heating and drying apparatus,
Since the surplus fine aggregate is stored in the surge bin 14 and the stored surplus fine aggregate is supplied to the dryer 8 in a fixed amount, there are the following advantages. That is, the arrival time of the aggregate from the feeder 6 to the hot bins 11 and 11A needs to be, for example, about 5 to 10 minutes. If the amount fluctuates without being constant, feeder 6
It takes a long time to keep the amount of fine aggregate circulated even if the amount of aggregate supplied by the
However, there is a problem that the temperature of the circulating belt conveyors does not become constant or the circulating belt conveyors 16A and 16B are in a use state exceeding the capacity and stop.

In this regard, if the surge bin 14 is provided as described above and the stored surplus fine aggregate is supplied to the dryer 8 in a fixed amount, the amount of fine aggregate cut out by the feeder 6 varies. Also, since the circulating amount of the surplus fine aggregate does not fluctuate and remains constant, the width of the amount of the aggregate controlled in the feeder 6 can be reduced as compared with the case where the surge bin 14 is not provided, and the circulating amount is reduced. Since it is constant, the control of the temperature of the aggregate in the dryer 8 can be constant.

In the dryer 8, the temperature of the aggregate to be heated and dried is controlled, and the temperature of the aggregate is detected by a thermocouple type thermometer. In this case, if the amount of coarse aggregate is large, the contact area at the detecting portion of the thermometer is small, so that accurate aggregate temperature cannot be detected. However, as described above, by circulating the fine aggregate, the contact area increases, an accurate aggregate temperature is detected, and an accurate temperature is displayed. There is an advantage that control can be performed accurately.

Although the present invention has been described with reference to the specific embodiment as described above, the present invention is not limited to this, and is attached to the present invention by a person skilled in the art. It should be noted that various changes and modifications can be made without departing from the scope of the claimed utility model registration claim.

[0025]

As described above, according to the aggregate heating and drying apparatus in the asphalt plant of the present invention, after the aggregate is supplied to the dryer and heated and dried, the aggregate is sieved by a particle size on a screen and sieved. Excessive fine aggregate among aggregates is collected by a shoot and stored in a surge bin, and the step of supplying the stored excessive fine aggregate to the dryer together with the aggregate to be heated and dried is repeatedly performed. As a result of circulating excess heat-dried fine aggregate to the dryer, it is possible to improve the heat drying property of the coarse aggregate in the dryer, improve the production capacity in the asphalt plant, and improve fuel efficiency. Savings can also be achieved.

In particular, according to the present invention, the surplus fine aggregate is stored in the surge bin, and the stored surplus fine aggregate is supplied to the dryer in a fixed amount. The control width can be reduced, and the control of the temperature of the aggregate in the dryer can be kept constant.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of an aggregate heating and drying apparatus in an asphalt plant according to the present invention.

[Explanation of symbols]

 8 Dryer 10 Screen 11 Hot Bin 11A Hot Bin 12 Aggregate Weighing Hopper 13 Chute 14 Surge Bin 15 Feeder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-33040 (JP, A) JP-A-64-33039 (JP, A) JP-A-64-33038 (JP, A) JP-A-61-33038 261246 (JP, A) JP-A-55-5901 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 14/00 C04B 20/02

Claims (1)

(57) [Scope of request for utility model registration] 1. An asphalt plant for producing an asphalt mixture, comprising an aggregate heating and drying apparatus for heating and drying the aggregate as a material of the asphalt mixture, a dryer for heating and drying the supplied aggregate, A screen for sieving the dried aggregate according to particle size, a chute for collecting the surplus fine aggregate of the sieved fine aggregate, a surge bin for storing the collected surplus fine aggregate, and a sieving And a feeder for supplying a certain amount of fine aggregate stored in the surge bin to the dryer, and a feeder for supplying a certain amount of fine aggregate stored in the surge bin to the dryer, and stored in the surge bin. An aggregate heating and drying apparatus in an asphalt plant, wherein a step of supplying surplus fine aggregate to the dryer together with the aggregate to be heated and dried is repeatedly performed.