JPH0144567Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is based on drying and heating of aggregate using a dryer, storing it in an aggregate storage tank according to particle size, and then storing the above aggregate as needed. The present invention relates to an asphalt plant in which aggregate is discharged from a tank to an aggregate measuring tank, the amount thereof is measured, and aggregates of various particle sizes are mixed together in a mixer to obtain a composite material.More specifically, it relates to a scavenging device installed in an asphalt plant. .

[Conventional technology]

In asphalt plants, in order to prevent pollution caused by dust generated inside the plant, the aggregate storage tank, aggregate measuring tank, and mixer are surrounded by a dust cover, and this dust cover is installed in a collector connected to the exhaust duct of the dryer. The dust cover is connected to the dust cover via a scavenging duct, and the dust cover is sucked out by the exhaust fan of the dust collector to prevent it from leaking to the outside.

[Problem that the invention attempts to solve]

However, in the above-mentioned conventional asphalt plants, the dust cover was only connected to the dust collector through the scavenging duct. When using additives, etc., if the amount of air to be scavenged increases in the dust cover due to the generation of water vapor, etc., it may not be possible to scavenge all of the air, and for this reason, dust may be removed from the gaps between various parts of the dust cover. The disadvantage was that the gases contained therein would blow out, making the working environment extremely bad.

[Means for solving problems]

In this invention, the dust cover is equipped with a pressure detection device that detects the pressure inside the dust cover and sends a detection signal to the control device, and the scavenging duct is equipped with an opening/closing damper whose opening and closing are controlled by the control device. By providing this, the above-mentioned conventional problems are solved.

[Effect]

After the aggregate is placed in a dryer and heated to dry,
It is separated by particle size and stored in aggregate storage tanks. The aggregates of each particle size stored in the aggregate storage tank are individually discharged from the storage tank to the aggregate measuring tank, and the amount is measured and put into the mixer, where the aggregates of each particle size are combined together. They are mixed to form a composite material.

In the above operation, the dust collector operates to suck in the exhaust gas from the dryer and the air in the dust cover to capture the dust contained therein. On this occasion,
The pressure detection device detects the pressure inside the dust cover and sends a detection signal to the control device. The control device that receives the detection signal from the pressure detection device opens the opening/closing damper if the pressure inside the dust cover is too high, or closes the opening/closing damper if the pressure is too low, so that the pressure inside the dust cover is lower than atmospheric pressure. The opening and closing of the opening/closing damper is automatically controlled to maintain a slightly lower, optimal pressure.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which 1 is a dryer equipped with a burner 2. In FIG. The aggregate is placed in the exhaust duct 3 of the dryer 1.
A conveyor 4 for feeding aggregate is provided, and a dust collector 8 consisting of a cyclone 5, a bag filter 6, and an exhaust fan 7 is connected to the exhaust duct 3.

Further, reference numeral 9 is an aggregate storage tank, which stores aggregates separated by a classifier (not shown) according to particle size. ) is supported. As usual, the classification device is provided above the aggregate storage tank 9, and a hot elevator (not shown) is provided between the dryer 1 and the above-mentioned classification device. The aggregate is transported to a classification device using a hot elevator.
An aggregate measuring tank 11 is provided directly below the aggregate storage tank 9, and a mixer 13 is provided below the aggregate measuring tank 11 and a filler measuring tank 12 arranged next to the aggregate measuring tank 11. The aggregate measuring tank 11 measures the amount of aggregate discharged from the aggregate storage tank 9 and puts it into the mixer 13, and the filler measuring tank 12 measures the amount of aggregate discharged from the aggregate storage tank 9, and the filler measuring tank 12 measures the amount of aggregate discharged from the aggregate storage tank 9. The filler is weighed and put into the mixer 13, and together with the aggregate storage tank 9 and the mixer 13, the dust cover 14
surrounded by. A scavenging duct 15 is provided in the dust cover 14 and communicates the dust cover 14 with the dust collector 8. The main structure of the above-mentioned asphalt plant is conventionally known.

16 is an opening/closing damper provided in the scavenging duct 15, and 17 is a dust cover 1.
This is a pressure sensing device attached to 4. The pressure detection device 17 is electrically connected to the control device 18, detects the pressure inside the dust cover 14, and sends a detection signal to the control device 18. The control device 18 is electrically connected to a drive device 19 such as a control motor that operates the opening/closing damper 16, and detects whether the pressure inside the dust cover 14 is high based on a detection signal sent from the pressure detection device 17. If the pressure is too low, the opening/closing damper 16 is opened, and if the pressure is too low, the opening/closing damper 16 is closed, and the opening/closing damper is operated via the drive device 19 so that the pressure inside the dust cover 14 is maintained at a pressure slightly lower than atmospheric pressure. The opening and closing of 16 is automatically controlled.

Next, the operation of the asphalt plant constructed as described above will be explained.

In FIG. 1, aggregates that have been dried and heated by a dryer 1 are sieved by particle size using a classifier;
Discharging, measuring, and mixing of the stored aggregate according to particle size from the aggregate storage tank 9, and capturing of dust by the dust collector 8 are performed in the conventional manner. Discharge the aggregate from the aggregate storage tank 9 into the aggregate measuring tank 11, and
1 or filler measuring tank 12 into the mixer 13, if the pressure inside the dust cover 14 changes due to dropping of the aggregate or filler or generation of water vapor, the pressure detection device 17 detects the change. The pressure change is detected and the detection signal is sent to the control device 18.
Control device 18 receives a signal from pressure sensing device 17
operates the drive device 19 to close the dust cover 1.
4, the opening/closing damper 16 is rotated in the opening direction when the pressure inside the dust cover 14 becomes high, and conversely, when the pressure is low, the opening/closing damper 16 is rotated in the closing direction to lower the inside of the dust cover 14 from atmospheric pressure. Keep the pressure a little lower. Therefore, even if a large amount of water vapor is generated within the dust cover 14 or the production amount of mixed material per unit time is increased, the pressure within the dust cover 14 will not become higher than atmospheric pressure. Therefore, dust generated within the dust cover 14 is prevented from leaking from the gaps.

FIG. 2 shows another embodiment of the present invention, in which an opening/closing damper 16 is provided in a bypass section 15a connected between an exhaust duct 3 and a cyclone 5, and a solenoid valve 20 is controlled by a control device 18. It is configured to be opened and closed by a driving device 19 consisting of a cylinder that is moved by opening and closing. Note that the other configurations other than those described above are the same as those shown in FIG. 1, so the same reference numerals are given and the explanation thereof will be omitted.

In the asphalt plant shown in FIG. 2, the pressure detection device 17, control device 18, drive device 19, and opening/closing damper 16 act in the same way as in FIG. Although the pressure is kept low, the opening/closing damper 16 is provided in the bypass section 15a of the scavenging duct 15.
Even if the opening/closing damper 16 is completely closed, the scavenging duct 1
5 is not completely blocked and the minimum amount of scavenging air in the dust cover 14 is ensured, which has the effect of making it easier to control the scavenging air in the dust cover 14.

Moreover, the bypass part 15a is connected between the exhaust duct 3 and the cyclone 5, and the opening/closing damper 1
6 is opened, the suction force from the exhaust fan 7 can cause the dust cover 14 to flow through the dust cover 14 without going through the cyclone 5.
This allows for efficient scavenging.
Note that the bypass portion 15a may be connected to the exhaust duct 3 as shown by the two-dot chain line in FIG.

Through the above two embodiments, the control device 18 is configured to control the rotation speed of the exhaust fan 7 in parallel with the opening/closing damper 16 or independently, thereby controlling the pressure inside the dust cover 14 over a wide range and It can also be done with high precision.

[Effect of idea]

As explained above, in the asphalt plant of the present invention, the dust cover is provided with a pressure detection device, and the opening/closing damper or scavenging duct whose opening/closing is controlled by the pressure detection device via the control device is provided, and the dust cover is provided with a pressure detection device. Since the internal pressure is kept slightly lower than atmospheric pressure, no matter what operating conditions the asphalt plant is under, only dust-containing gas will be blown out, achieving environmental conservation and pollution prevention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of an asphalt plant of the present invention, and FIG. 2 is an explanatory diagram showing another embodiment. 2... Dryer, 3... Exhaust duct, 7... Exhaust fan, 8... Dust collector, 9... Aggregate storage tank, 11
... aggregate measuring tank, 13 ... mixer, 14 ... dust cover, 15 ... scavenging duct, 16 ... opening/closing damper, 17 ... pressure detection device, 18 ... control device.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A dryer for drying and heating aggregate, an aggregate storage tank for storing aggregate dried and heated by this dryer, and an aggregate storage tank disposed under this aggregate storage tank. an aggregate measuring tank for measuring aggregate discharged from the material storage tank;
A mixer is provided below the aggregate measuring tank and mixes the aggregate discharged from the aggregate measuring tank, and a dust cover is provided on the aggregate storage tank, the aggregate measuring tank, and the mixer. In an asphalt plant where a dust collector having an exhaust fan is connected to the exhaust duct of the dryer and the scavenging duct of the dust cover, the duct cover detects the pressure inside the dust cover and transmits the detection signal to a control device. An asphalt plant, characterized in that the scavenging duct is provided with an opening/closing damper whose opening/closing is controlled by the control device. (2) The asphalt plant according to claim 1, wherein the opening/closing damper is provided in a bypass section of a scavenging duct connected to a dust collector.