JPH0218090Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to an asphalt plant for producing an asphalt mixture used for the surface base layer and roadbed of asphalt pavement.

``Conventional technology'' In an asphalt plant, aggregates of various particle sizes are put into a dryer, dried and heated by combustion gas from a burner, and the dried and heated aggregates are sent to a screen using a hot elevator (bucket elevator) to be sieved. The aggregate is separated and stored in hot pins according to particle size, and the stored aggregate is put into a mixer and mixed with asphalt, filler, etc. at a predetermined mixing ratio to produce an asphalt mixture. and,
Its operation has become intermittent.
Further, the exhaust gas discharged from the dryer is discharged into the atmosphere by an exhaust fan via a dust collector, and the dust in the exhaust gas is collected and removed by the dust collector.

``Problem that the invention seeks to solve'' By the way, the asphalt plant as a whole is operated intermittently, but the dryer's rotating drum, exhaust system, and hot elevator are operated idly for a certain period of time from the time of suspension to the restart of operation. . This means that if these are stopped when the plant is shut down,
This is because the rotary drum itself may be thermally deformed due to residual heat within the rotary drum, and this is prevented by slowly cooling the rotary drum by running the rotary drum idly and performing an air cooling operation. However, during this idle operation, fine aggregate particles and suspended dust (hereinafter referred to as dust) are sent from the dryer to the screen via the hot elevator, and settle and accumulate in the fine particle storage chamber of the hot pin. As a result, there was a problem in that the aggregate particle size structure within the hot pin was disrupted and the quality of the asphalt mixture deteriorated in the early stages after restarting operation.

This invention was made in view of the above circumstances,
To provide an asphalt plant which prevents dust from accumulating in hot pins during idle operation during suspension and maintains good quality of asphalt mixture.

"Means for Solving the Problems" In order to achieve the above object, the asphalt plant of the present invention connects a discharge duct between the input chute at the end of the hot elevator and the dust collector, and also connects the input chute to the dust collector. A short pipe is installed at the bottom of the part to suck outside air into the input chute part.
In addition, the discharge duct and the short pipe are each provided with an opening/closing damper.

"Operation" In the asphalt plant of the present invention, both opening and closing dampers are closed during normal operation, but both opening and closing dampers are opened during idle operation during rest. As a result, outside air is sucked into the input chute section, and the outside air is sent to the dust collector through the exhaust duct, and the flow of outside air causes the hot elevator to pass through the input chute section to the mixer side. The emitted dust is sent to a dust collector and removed.

"Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Figure 1 shows the overall configuration of an asphalt plant.
an aggregate yard 1 for storing aggregates; a dryer 2 for drying and heating the aggregate Ag taken out from the aggregate yard 1 with combustion gas from a burner 2a; and a dryer 2 for transporting the aggregate Ag dried and heated by the dryer 2. It is equipped with a hot elevator 3, a screen 4 that classifies and sieves the aggregate Ag transported by the hot elevator 3 according to particle size, and a plurality of storage chambers 5a, and separates the aggregate Ag classified by the screen 4 according to particle size. It has a hot pin 5 accommodated in each storage chamber 5a, an aggregate measuring tank 6 for taking out aggregate Ag from the hot pin 5 and weighing it, a filler tank 7 for storing filler F, and a screw from the filler tank 7. A bucket elevator 9 that transports the filler F taken out by the conveyor 8 together with dust D, which will be described later, and a filler pin 10 that accommodates the filler F transported by the bucket elevator 9.
, a dust pin 11 that accommodates dust D, a filler/dust measuring tank 12 that takes out and weighs filler F and dust D from these pins 10 and 11, respectively, and asphalt sent from an asphalt tank (not shown). It is equipped with an asphalt measuring tank 13 for measuring As. Then, the aggregate Ag weighed in the aggregate measuring tank 6, the filler F and dust D weighed in the filler/dust measuring tank 12, and the asphalt measuring tank 13
The asphalt As weighed in the mixer 14
and mixed with each other to produce asphalt mixture.

Further, an exhaust fan 16 is connected to the dryer 2 via a connecting duct 17, which sucks exhaust gas generated in the dryer 2 and releases it into the atmosphere from a chimney 15. Dust collector 18 that removes dust and collects dust D therein
is provided. This dust collector 18 includes a cyclone section 19 that removes dust from exhaust gas from the dryer 2.
and a bag filter part 20 that further removes dust from the exhaust gas that has passed through the cyclone part 19. are connected by an internal duct 21 that penetrates the interior of the . Then, the relatively coarse-grained dust D removed by the cyclone section 19 is transferred to the receiving port 22 of the hot elevator 3, and
The relatively fine dust D removed by the bag filter section 20 is fed into the receiving port 9a of the bucket elevator 9 by a screw conveyor 23 at the bottom of the bag filter section 20.

Further, on the upper surface of the input chute section 24 provided at the terminal end of the hot elevator 3, near the joint between the input chute section 24 and the cover 4a of the screen 4, and the exhaust air of the cyclone section 19 of the dust collector 18, A discharge duct 25 having substantially the same flow path cross-sectional area as the communication port between the input chute section 24 and the screen 4 is connected between the input chute section 24 and the screen 4, and
This discharge duct 25 is provided with a first opening/closing damper 26 that opens and closes the flow path. Also, the input chute 2 is connected to the lower side of the input chute 24.
4 and the screen 4 is provided with a short pipe 27 that opens the inside of the input chute part 24 to the outside. A second opening/closing damper 28 is attached. The first and second opening/closing dampers 26 and 28 are automatically brought into an open state when the burner 2a of the dryer 2 is stopped, and are automatically brought into a closed state when the burner 2a is ignited. It is configured as follows.

A liner 29 for wear prevention is attached to the inner bottom side of the input chute 24 of the hot elevator 3, and a chevron-shaped protrusion is provided on the upper surface of the liner 29 to maintain the appropriate falling speed of the aggregate Ag. A plurality of strips 30 are formed in a direction transverse to the input chute portion 24 . In addition, 31 in the figure is the high temperature scavenging air generated in the screen 4 etc.
This is a duct for guiding the air to the burner 2a side of the dryer 2 via the fan 32, and the scavenging air guided by this duct 31 is used for combustion in the burner 2a.

However, in the asphalt plant with the above configuration, during normal operation, the first and second opening/closing dampers 2
6 and 28 are in a closed state. Then, as in the past, aggregate Ag of various particle sizes is taken out from the aggregate yard 1, carried into the dryer 2, dried and heated, and then sent to the screen 4 by the hot elevator 3 where it is classified. Each storage room 5a
be accommodated in. Next, a predetermined amount of aggregate Ag is taken out from the hot pin 5 and weighed in an aggregate measuring tank 6.
It is put into the mixer 14. Further, the exhaust gas generated in the dryer 2 is removed from the cyclone section 1 of the dust collector 18.
9. The dust D that has been successively removed through the bag filter section 20 and removed by the cyclone section 19 is thrown into the hot elevator 3, while the dust D that has been removed by the bag filter section 20 is sent to the dust pin via the bucket elevator 9. It is housed in 11.
Furthermore, the filler F is taken out from the filler tank 7 by the screw conveyor 8 and stored in the filler pin 10 by the bucket elevator 9. A predetermined amount of filler F and dust D are taken out from each of these pins 11 and 10 and weighed in a filler/dust measuring tank 12, and the weighed filler F and dust D are fed into a mixer 14 together with asphalt As, additives, etc. and mixed with the above aggregate Ag to produce an asphalt composite material.

On the other hand, when the dryer 2 is stopped, the rotary drum 2b of the dryer 2, exhaust system equipment such as the exhaust fan 16, and the hot elevator 3 are operated idly for a certain period of time after the burner 2a of the dryer 2 is stopped.
The dust D remaining in the rotating drum 2b and the hot elevator 3 is discharged from the hot elevator 3 into the screen 4. However, in the above asphalt plant, burner 2a of dryer 2
When the motor stops, the first and second dampers 26 and 28 are opened. Then, due to the suction of the exhaust fan 16, the outside air enters the input chute section 24 through the short pipe 27 and is guided to the discharge duct 25, but the dust D falling from the input chute section 24 into the screen 4 is removed.
This outside air flow leads to the dust collector 18 through the exhaust duct 25, where it is captured and removed by the bag filter section 20. Therefore, there is no risk that the dust D will accumulate in the hot pins 5 and the aggregate particle size structure will be disrupted, resulting in a deterioration in the quality of the asphalt mixture when the operation is restarted, as in the conventional case.

Here, since the discharge duct 25 is connected to the input chute 24 of the hot elevator 3, the dust D in the equipment from the dryer 2 to the terminal end of the hot elevator 3 is collected by the single discharge duct 25. It can lead to 18. In addition, the flow passage cross-sectional area of the discharge duct 25 is set to be sufficiently large, and the outside air flowing in from the short pipe 27 is blown upward from the bottom of the input chute 24, so that the air flows into the input chute 24. Arrived Dust D
can be guided to the discharge duct 25 reliably and efficiently. Furthermore, the first and second opening/closing dampers 2
6 and 28 are designed to be automatically opened and closed in conjunction with the stoppage of the burner 2a of the dryer 2, so that the workability is good.

Incidentally, in the above embodiment, the discharge duct 25 is connected to the exhaust part 19a of the cyclone part 19 of the dust collector 18, but it may be connected to the suction side of the cyclone part 19. Further, other types of dust collectors 18 may be used.

"Effects of the Invention" As explained above, the asphalt plant of the present invention connects the discharge duct between the input chute at the end of the hot elevator and the dust collector, and connects the outside air to the lower part of the input chute. A short pipe for suction is provided in the input chute, and
An opening/closing damper is provided in each of the discharge duct and the short pipe, and by opening these dampers during idle operation during idle operation, outside air is sucked into the input chute through the short pipe, and the dust collector is installed through the discharge duct. Since the outside air flow collects the dust that reaches the input chute, the dust accumulates inside the hot pin during dry operation and changes the aggregate particle size structure. There were no problems such as collapse,
It is possible to consistently produce asphalt composite materials of good quality.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an asphalt plant of the present invention, and FIG. 2 is a schematic diagram of the main parts. 2...Dryer, 3...Hot elevator, 4
... Screen, 14 ... Mixer, 18 ... Dust collector, 24 ... Input chute section, 25 ... Discharge duct, 26 ... First opening/closing damper, 27 ... Short pipe,
28...Second opening/closing damper.

Claims (1)

[Scope of utility model registration request] Aggregates are put into a dryer and heated and dried using combustion gas from a burner. The dried and heated aggregates are sent to a screen using a hot elevator to be sieved by particle size, and the sieved aggregates are mixed with asphalt etc. in a mixer. In an asphalt plant in which asphalt mixture is produced by mixing and the dust in the exhaust gas discharged from the dryer is collected and removed by a dust collector, the input chute at the end of the hot elevator and the collection A discharge duct is connected between the dust device and the dust collector, and a short pipe is provided at the bottom of the input chute to draw outside air into the input chute. An asphalt plant characterized in that the discharge duct and the short pipe are each provided with an opening/closing damper.