WO2003061926A1

WO2003061926A1 - Apparatus for thermally processing aggregate to fabricate asphalt-concrete

Info

Publication number: WO2003061926A1
Application number: PCT/KR2003/000128
Authority: WO
Inventors: Yong-Gu Lee
Original assignee: Hongsan Construction Co., Ltd.
Priority date: 2002-01-22
Filing date: 2003-01-21
Publication date: 2003-07-31
Also published as: KR100383058B1

Abstract

Heated aggregate is mixed with asphalt and various fillers in a mixer in order to fabricate asphalt-concrete. An apparatus for thermally processing aggregate heats, conveys and stores large quantity of aggregates to fabricate asphalt-concrete and prevents a thermal-loss by circulating heated air. The apparatus blows heated air into first and second driers by using an electric hot wind generator, which heats air by using electricity, thereby heating aggregate filled in the first and second driers.

Description

APPARATUS FOR THERMALLY PROCESSING AGGREGATE TO FABRICATE ASPHALT-CONCRETE

Technical Field The present invention relates to an apparatus for thermally processing aggregate to fabricate asphalt-concrete. In order to fabricate asphalt-concrete, aggregate that has been heated is mixed with asphalt and various fillers in a mixer. The present invention particularly relates to an apparatus for thermally processing aggregate, which heats, conveys and stores large quantity of aggregates to fabricate asphalt-concrete and prevents a thermal-loss by circulating heated air.

Background Art

Generally, asphalt-concrete used in a road is fabricated by mixing asphalt (hydrocarbon compound) with aggregate including crushed stone, sand, stone debris and gravel. In order to easily mix the above elements with each other, aggregate is heated before mixing the above elements.

Conventionally, in order to heat aggregate, an oil burner is installed at a front of a drier so as to heat aggregate filled in the drier. The conventional oil burner requires air and fuel including bunker-C oil to burn articles. However, the conventional oil burner consumes large quantity of fuels when burning articles so that the fuel cost is increased. In addition, contaminated air generated in the process of combustion is exhausted into atmosphere so that atmosphere is contaminated, thereby causing an environmental problem.

Hereinafter, a conventional asphalt-concrete manufacturing apparatus will be described with reference to FIG. 1. As shown in FIG. 1, the conventional asphalt-concrete manufacturing apparatus conveys aggregate, such as crushed stone, sand, stone debris and gravel, from aggregate containers 10 into a drier 30 through a belt 20 and heats the aggregate filled in the drier 30 by using an oil burner 40. At this time, particles or contaminated gas generated from the oil burner 40 is exhausted into an exterior through an air exhausting device 45 and a dust collecting device (not shown). In addition, aggregates heated in the drier 30 are moved into a screen 50 through a conveying elevator 80, in which aggregates are classified into several groups depending on sizes thereof. Then, aggregate is moved into a mixer 60, where the aggregate is mixed with asphalt and fine fillers supplied from a filler tower 70, thereby forming asphalt-concrete. Asphalt-concrete is loaded on an asphalt-concrete conveying vehicle positioned below the mixer 60 and transferred into a required place.

The conventional asphalt-concrete manufacturing apparatus directly heats bunker-C oil by using the oil burner in order to heat gravel, sand and crushed stone, so not only are large quantity of fuels consumed, but also contaminated gas and fine particles are exhausted into atmosphere, thereby contaminating atmosphere.

Besides the environmental problem, the oil burner generates noise so the conventional asphalt-concrete manufacturing apparatus is not adapted to be used in an urban area. In addition, the prime cost and thermal energy cost of the conventional asphalt- concrete manufacturing apparatus are increased. Furthermore, about 70% of thermal energy is exhausted to atmosphere together with exhaust gas, so that thermal efficiency is lowered. In addition, since the conventional asphalt-concrete manufacturing apparatus has huge dust-collecting equipment, it is required to periodically exchange a bag filter with new bag filter so that the maintenance and repairing cost is increased.

Disclosure of the Invention

The present invention has been made to solve the above problems of the related art, therefore, it is an object of the present invention to provide an apparatus for thermally processing aggregate to fabricate asphalt-concrete, which heats aggregate by using an electric hot wind generator, instead of an oil burner, so that heated air is circulated in a loop-pattern, thereby minimizing thermal energy loss and saving fuel as used.

Another object of the present invention is to provide an apparatus for thermally processing aggregate to fabricate asphalt-concrete, which retrieves remaining waste heat after heating aggregate and reuses waste heat as a heat source by circulating heated air through a blowing fan and a funnel, thereby saving a thermal energy required for heating aggregate.

Still another object of the present invention is to provide an apparatus for thermally processing aggregate to fabricate asphalt-concrete, which remarkably reduces noise by using an electric hot wind generator and fabricates asphalt-concrete in an environmental-friendly manner by preventing harmful gas and fine particles from .being exhausted into atmosphere. To achieve the above objects, there is provided an apparatus for fabricating asphalt-concrete, the apparatus comprising: first to fourth conveyers for conveying aggregate; an elevator for upwardly moving aggregate; a plurality of manifolds for branching aggregate by comparing a heating temperature of aggregate with a predetermined temperature; a plurality of chutes connected to the manifolds in order to convey branched aggregate; a hot silo for storing aggregate conveyed from one of the chutes; and a means for thermally processing aggregate including a first drier installed at a lower end of the first conveyer so as to primarily heat aggregate introduced therein from the first conveyer while rotating aggregate, a second drier connected to the first drier through an aggregate conveying path and a second funnel of heated air in order to secondarily heat aggregate while rotating aggregate, an electric hot wind generator installed at a front of the second drier so as to supply heat to the first and second driers through a first funnel and having a plurality of heating fins therein, a cyclone installed on a third funnel, which connects the first drier to the electric hot wind generator, in order to primarily filter air after heating aggregate, a filtering device installed next to the cyclone so as to secondarily filter minute particles or dusts, and a blower installed next to the filtering device so as to blow air contained in the third funnel towards the electric hot wind generator.

A first measuring device is installed on the first conveyer so as to measure an amount of new aggregate to be introduced into the first drier, and a second measuring device is installed on the second conveyer so as to measure an amount of heated aggregated to be discharged.

In addition, an infrared ray temperature sensor is installed on the second conveyer in order to detect a temperature of heated aggregate.

Brief Description of the Drawings

The above objects, and other features and advantages of the present invention will become more apparent by describing preferred embodiments thereof with reference to the attached drawings in which: FIG. 1 is a schematic view showing a conventional asphalt-concrete fabricating apparatus; and

FIG. 2 is a schematic view showing an asphalt-concrete fabricating apparatus having an apparatus for thermally processing aggregate according to one embodiment of the present invention.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic view showing an asphalt-concrete fabricating apparatus having an apparatus for thermally processing aggregate according to one embodiment of the present invention. As shown in FIG. 2, the apparatus for thermally processing aggregate according to one embodiment of the present invention heats aggregate by converting an electric energy into a thermal energy. At this time, air is used as a thermally conductive medium, so that air is fed-back and re-circulated until heat is completely conducted. Accordingly, 100% of the thermal energy can be used, thereby remarkably increasing thermal efficiency. That is, the apparatus for thermally processing aggregate of the present invention heats air through an electric hot wind generator and compresses heated air by using a blower so as to blow heated air into a drum-type drier, which rotates with accommodating aggregate therein. Thus, aggregate receives heat from heated air. In this manner, air is used as a thermally conducive medium and used air is re-circulated into the electric hot wind generator through a funnel and re-heated by the electric hot wind generator, so the thermal efficiency is maximized.

In detail, the apparatus for thermally processing aggregate of the present invention conveys aggregate through a plurality of conveyers 110, 130 and 140 and circulates air heated by electricity through funnels 191, 193 and 195. Firstly, new aggregate is inputted through a first conveyer 110 having a first measuring device 115 thereon for measuring quantity of aggregate to be introduced. Aggregate conveyed by the first conveyer 110 is inputted into a first drum-type drier 120 and rotates in the first drum-type drier 120 when the first drum-type drier 120 is rotated. A second drier 125 is sequentially installed next to the first drier 120. The first drier 120 is connected to the second drier 125 through an aggregate conveying path 123 for conveying aggregate and a funnel 193 for circulating heated air. In addition, a second conveyer 130 for conveying heated aggregate is installed at one end of the second drier 125 A second measuring device 135 for measuring an amount of heated aggregate to be discharged and a non-contact type infrared ray temperature sensor 137 for measuring the temperature of heated aggregate are installed on the second conveyer 130 An end of the second conveyer 130 is connected to a lower end of an elevator 139, which conveys aggregate in an upper direction A third conveyer 140 is connected to an upper end of the elevator 130

In addition, a first manifold 145 is connected to an end of the third conveyer 140 so as to allow aggregate to be conveyed into a proper place depending on the temperature of aggregate and productivity of asphalt-concrete A first chute 147, which conveys aggregate to store it in a hot silo 150 if aggregate has an improper temperature, and a second chute 149, which conveys aggregate towards a screen 165 if aggregate has a proper temperature, are connected to the first manifold 145 In addition, a second manifold 155 is mounted at an end of the first chute 147 so as to branch aggregate A third chute 157, which conveys aggregate into the first drier 120 in order to heat aggregate if aggregate has an improper temperature, and a fourth chute 159, which conveys aggregate into the hot silo 150 so as to store aggregate in the hot silo 150 for fabricating asphalt-concrete later The hot silo 150 having a large capacity to store large quantity of heated aggregates is installed below the fourth chute 159, and a fourth conveyer 160 for conveying aggregate into a next stage is installed below the hot silo 150 A heating wire or a heat-keeping member can be provided to keep warmth for an outer portion of the hot silo 150 In this case, aggregate can be stored in the hot silo 150 for 48 hours

The first and second manifolds 145 and 155 are generally used in the asphalt- concrete fabricating apparatus and well known in the art The first and second manifolds 145 and 155 have a two-way damper, which selectively opens/closes one of fluid paths to branch aggregate upon receiving an order from a control section The first and second manifolds 145 and 155 will not be further described below

An end of the fourth conveyer 160 is communicated with the lower end of the elevator 169 and the upper end of the elevator 169 is connected to the screen 165 through a separate feeding line 168 A mixer 170 is installed at a lower end of the screen 165 in order to fabricate asphalt-concrete by mixing aggregate filtered through the screen 165. with asphalt In addition, a filler tower 175 is installed at a side of the mixer 170 Fillers supplied from the filler tower 175 are filled into a gap formed between aggregate and asphalt.

An electric hot wind generator 190 for heating air by using electricity is installed at a front of the second drier 120 in order to heat aggregate filled in the first and second driers 120 and 125. The electric hot wind generator 190 is connected to the second drier

125 through a funnel 191. The electric hot wind generator 190 is provided at an inner portion thereof with a plurality of heating fins (not shown) formed in a zigzag pattern so as to effectively heat air, which passes through the electric hot wind generator 190. The heating fin is made of special material, such as INCOROY, capable of enduring against the high temperature. The electric hot wind generator 190 is equipped with an SCR (silicon controlled rectifier) as a safety device for the high temperature and hot heat, so the electric hot wind generator 190 can evenly heat aggregate while maintaining the proper temperature.

In addition, a cyclone 181 for primarily filtering air exhausted from the first drier 120 through the funnel 195, a filtering device 183 for secondarily filtering minute dust, and a blower 185 for blowing air towards the electric hot wind generator 190 by compressing air are sequentially installed next to the first drier 120.

The cyclone 181, which is a primary filtering device, collects large quantity of dusts with collecting efficiency of 75 to 85%. The filtering device 183, which is a secondary filtering device, includes a bag filter for filtering and collecting minute dusts by using non-woven fabric.

Hereinafter, an operation of the aggregate processing apparatus according to the present invention will be described.

Arrows shown as dotted lines in FIG. 2 represent a moving route of heated air, and arrows shown as solid lines in FIG. 2 represent a conveying route of aggregate.

Firstly, new aggregate is introduced into the first drier 120 from a separate aggregate container (not shown) through the first conveyer 110. At this time, the first measuring device 115 measures an amount of new aggregate introduced into the first drier

120. Then, aggregate is moved into the second drier 125 through the aggregate conveying path 123.

Upon starting the operation, air compressed by the blower 185 is filled in the electric hot wind generator 190. Air filled in the electric hot wind generator 190 is heated by electricity and heated air is introduced into the second drier 125 via the funnel 191. Thus, aggregate rotated in the second drier 125 receives heat from heated air so that aggregate is secondarily heated. Aggregate has been primarily heated by heated air, which is introduced into the first drier 120 through the funnel 193 so as to heat aggregate filled in the first drier 120. After heating aggregate, heated air moves through the funnel 195. At this time, heated air passing through the funnel 195 has a predetermined temperature lower than an initial temperature thereof caused by a thermal conduction. Heated air is primarily filtered through the cyclone 181, and secondarily filtered through the filtering device 183. Thus, filtered air is compressed by means of the blower 185 and introduced into the electric hot wind generator 190.

Since air passing through the blower 185 has a predetermined temperature, it is easy to increase the temperature of air up to a predetermined level, so an amount of fuel required for increasing the temperature of air up to the predetermined level can be reduced. Aggregate heated through the second drier 125 is moved into the elevator 139 through the second conveyer 130. At this time, the second measuring device 135 measures an amount of heated aggregate to be discharged, and the non-contact type infrared ray temperature sensor 137 detects the temperature of heated aggregate.

At this time, if the amount of heated aggregate to be discharged is identical to the amount of new aggregate measured by the first measuring device 115, the first conveyer 110 is operated in order to introduce new aggregate into the first drier 120. In addition, an optimum temperature is manually inputted into the non-contact type infrared ray temperature sensor 137. If the temperature detected by the non-contact type infrared ray temperature sensor 137 is higher than the optical temperature, heated aggregate is conveyed into the screen 165 or the hot silo 150. Otherwise, if the temperature detected by the non-contact type infrared ray temperature sensor 137 is lower than the optical temperature, aggregate is returned to the first drier 120 and is re-heated therein.

Heated aggregate conveyed through the elevator 139 is introduced into the first manifold 145 by means of the third conveyer 140. At this time, if the temperature of conveyed aggregate is lower than the optical temperature so that it is required for conveyed aggregate to be re-heated or stored in the hot silo 150, aggregate is moved into the second manifold 155 through the first chute 147. Otherwise, if the temperature of conyeyed aggregate is higher than the optical temperature adapted for fabricating asphalt-concrete, aggregate falls down on the fourth conveyer 160 through the second chute and is introduced into the elevator 169. The elevator 169 upwardly moves aggregate so that aggregate is inputted into the screen 165 via the feeding line 168. At this time, aggregate is classified into several groups depending on sizes thereof. In addition, if the detected temperature of heated aggregate introduced into the second manifold 155 is lower than the optimum temperature, heated aggregate is returned to the first drier 120 through the third chute 157 so as to be re-heated therein. If the detected temperature of heated aggregate introduced into the second manifold 155 is identical to or higher than the optimum temperature, heated aggregate is moved into the hot silo 150 through the fourth chute 159.

In this state, if it is required to supply aggregate, a predetermined amount of aggregate falls down on the fourth conveyer 160 depending on an order from a control section (not shown). Then, aggregate is upwardly moved by means of the elevator 169 and introduced into the screen 165 via the feeding line 168. While passing through the screen 165, aggregate is classified into several groups depending on sizes thereof.

Finally, aggregate classified through the screen 165 is introduced into the mixer 170, where aggregate is mixed with fillers supplied from the filler tower 175 and asphalt so as to fabricate asphalt-concrete.

Asphalt-concrete fabricated through the above processes is loaded in a separated vehicle and conveyed into a required place.

As described above, an apparatus for thermally processing aggregate to fabricate asphalt-concrete according to the present invention heats aggregates by using an electric hot wind generator, instead of an oil burner, in such a manner that heated air can be recirculated in a loop-pattern. Thus, thermal energy loss can be minimized and fuel to be used can be saved.

In addition, the present invention can remarkably reduce noise by using an electric hot wind generator and can fabricate asphalt-concrete in an environmental-friendly manner by preventing harmful gas and fine particles from being exhausted into atmosphere.

Furthermore, it is possible to store heated aggregate in a large silo for a long time, so productivity of asphalt-concrete can be improved.

While the present invention has been described in detail with reference to the preferred embodiments thereof, it should be understood to those skilled in the art that various changes, substitutions and alterations can be made hereto without departing from the scope of the invention as defined by the appended claims.

Claims

1. An apparatus for fabricating asphalt-concrete, the apparatus comprising: first to fourth conveyers for conveying aggregate; an elevator for upwardly, moving aggregate; a plurality of manifolds for branching aggregate by comparing a heating temperature of aggregate with a predetermined temperature; a plurality of chutes connected to the manifolds in order to convey branched aggregate; a hot silo for storing aggregate conveyed from one of the chutes; and a means for thermally processing aggregate including, a first drier installed at a lower end of the first conveyer so as to primarily heat aggregate introduced therein from the first conveyer while rotating aggregate, a second drier connected to the first drier through an aggregate conveying path and a second funnel of heated air in order to secondarily heat aggregate while rotating aggregate, an electric hot wind generator installed at a front of the second drier so as to supply heat to the first and second driers through a first funnel and having a plurality of heating fins therein, a cyclone installed on a third funnel, which connects the first drier to the electric hot wind generator, in order to primarily filter air after heating aggregate, a filtering device installed next to the cyclone so as to secondarily filter minute particles or dusts, and a blower installed next to the filtering device so as to blow air contained in the third funnel towards the electric hot wind generator.

2. The apparatus as claimed in claim 1, further comprising a first measuring device installed on the first conveyer so as to measure an amount of new aggregate to be introduced into the first drier, and a second measuring device installed on the second conveyer so as to measure an amount of heated aggregated to be discharged.

3. The apparatus as claimed in claim 1, further comprising an infrared ray temperature sensor installed on the second conveyer in order to detect a temperature of heated aggregate.