JPS6233762Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an asphalt plant for producing asphalt mixture from cold aggregate.

Asphalt plants, as is well known, dry and heat cold aggregate made of sand, crushed stone, etc., and mix this with stone powder and asphalt to produce asphalt mixture.The cold aggregate is dried with combustion air from a burner. A dryer that heats, a screen that classifies the aggregate sent from the dryer via a hot elevator (conveying device) according to particle size, and a mixer that mixes the required amount of aggregate taken out from this screen with stone powder and asphalt. Be equipped.

Incidentally, scavenging air is generated in the hot elevator, screen, and mixer. This scavenging air is usually about 90 ~
It has a high temperature of 110℃ and contains about 20 to 30 g/ ^Nm3 of dust and 5 to 10% moisture, but conventionally, it is released into the atmosphere by an exhaust fan through a dust collector along with the exhaust gas generated by a dryer. Ta. However,
Since the above-mentioned scavenging air is not a combustion gas but a high-temperature gas containing a large amount of oxygen, it is extremely unreasonable and unsatisfactory from the viewpoint of energy saving to release it into the atmosphere without using it.

The present invention includes a fuel injection nozzle inside, and has an air outlet opened at one end of the dryer body.
Further, an air swirling chamber with a hood opening at one end of the dryer main body is formed on the outer periphery of the air outlet of the burner casing, which is provided with the air intake port connected to the burner blower, and is provided almost concentrically with the hood. A duct connects the conveying device, a screen, and one or more of the mixers, and the scavenging air generated by the conveying device, screen, and mixer connected to the hood is sent to the dryer body through the swirling chamber. The above-mentioned conventional dissatisfaction has been resolved by providing an auxiliary blower that blows into the dryer, reducing the amount of clean combustion air supplied to the burner of the dryer and reducing the capacity and power of the blower used to supply this air. It is an object of the present invention to provide an asphalt plant that has the practical advantage of reducing the capacity and power of an exhaust fan for discharging exhaust gas generated in a dryer, as well as the capacity of a dust collector.

The present invention will be explained in detail below based on the drawings.
Figures 1 to 6 show an embodiment of the present invention, and the asphalt plant includes a dryer 1 that dries and heats cold aggregate A, and sieves the aggregate A that has been dried and heated in this dryer 1 according to particle size. screen 2
, an aggregate measuring tank 3 for weighing the aggregate A sieved by the screen 2, and an asphalt mixture by stirring and mixing the aggregate A weighed in the aggregate measuring tank 3 with filler B, asphalt C, etc. The main component is a mixer 4 that generates .

As shown in FIG. 2, the dryer 1 has an aggregate input port 6 and an aggregate discharge port 7 provided in a rotary furnace 5 which is tilted at a predetermined angle and rotatably provided, and a dryer main body 8 is provided. A burner 9 is disposed on one side of the aggregate discharge port 7. A conveyor 10 is attached to the aggregate input port 6, and this conveyor 10 removes bones (not shown). Cold aggregate A taken out from the material hopper is transferred to dryer 1.
It is now being brought into the country. Further, an exhaust fan 12 is connected to the upper part of the aggregate input port 6 via a duct 13 for sucking in the exhaust gas burned in the dryer body 8 and discharging it into the atmosphere through a chimney 11. A cyclone 1 is provided between the dryer main body 8 and the cyclone 1 for removing dust from the exhaust gas.
4 and a bug filter 15 are provided. Furthermore, as shown in FIGS. 3 to 5, the burner 9 has a cone-shaped air outlet 16a at one end,
A cylindrical casing 16 having an air intake port 16b on the side of the other end is disposed in the dryer main body 8 with its air blowing port 16a fitted into an opening formed in the wall surface on one side of the aggregate discharge port 7. A needle-type fuel injection nozzle 17 is provided inside the casing 16 with its tip facing the center of the air outlet 16a, and an ignition device 18 is provided near the fuel injection nozzle 17. A pair of electrode rods 1
8a and 18b have their respective tips connected to fuel injection nozzles 17.
It is attached oppositely to the tip of the. Then, a fuel pump (not shown) supplies fuel to the fuel injection nozzle 17 and injects it from its tip,
The ignition device 18 is applied to generate a spark between the tips of the electrode rods 18a and 18b to ignite the fuel injected from the fuel injection nozzle 17, and the burner blower 19 is used to blow the fuel into the casing 16 from the intake port 16b.
Clean air is sent inside to cause combustion, and this is sent to the air outlet 1.
It is designed to be supplied into the dryer main body 8 from 6a. Further, a control rod 20 is attached to the base end of the fuel injection nozzle 17 and the control rod 20 is attached to the base end of the fuel injection nozzle 17.
This control rod 2 is provided through the
0 is connected to a control motor 22 via a link mechanism 21 composed of a plurality of rods 21a, levers 21b, etc.
On the other hand, a damper 23 is disposed at the intake port 16b of the casing 16, and this damper 2
3 is connected to the control motor 22 via a link mechanism 24 consisting of a plurality of rods 24a, levers 24b, etc. When the control motor 22 is operated, the opening degree of the damper 23 is adjusted via the link mechanism 24, and the control rod 20 is rotated in the circumferential direction via the link mechanism 21, thereby injecting fuel. The fuel injection amount of the nozzle 17 is adjusted in conjunction with the opening degree of the damper 23.

Further, a substantially cylindrical hood 25 having a diameter larger than the air outlet 16a of the casing 16 is provided in an opening portion on one side of the aggregate discharge port 7 of the dryer 1 into which the casing 16 of the burner 9 is fitted.
6, an air swirling chamber m is formed, and one end of a duct 26 is connected to the hood 25 from the tangential direction of the hood 25, and the other end of the duct 26 is connected to the duct 26 on the suction side. 2
7 to the screen 2, the surrounding areas of the aggregate measuring tank 3 and the mixer 4, and the hot elevator 2 to be described later.
It is connected to the discharge side of the auxiliary blower 29 connected to the air blower 8 . Then, screen 2, aggregate measuring tank 3
, mixer 4, etc. and hot elevator 2
The scavenging air generated in step 8 is sent to the auxiliary blower 29.
The air is introduced from the side into the air swirling chamber m, passes through the air swirling chamber m while swirling, flows into the tip of the burner 9, and is burned together with the fuel gas from the burner 9. Also,
In the duct 26 on the discharge side of the auxiliary blower 29,
Damper 23 of the intake port 16b of the casing 16
A damper 30 whose opening degree is controlled based on the opening degree of the damper 30 is provided, and the amount of scavenging air supplied by the auxiliary blower 29 is adjusted in accordance with the amount of clean air supplied to the burner 9 by the burner blower 19. It is becoming more and more common.

On the other hand, a discharge chute 31 is provided below the aggregate discharge port 7 of the dryer 1, and this discharge chute 31 is provided with a hot elevator (conveying device) 28 for conveying the aggregate A to the screen 2. The above-mentioned duct 27 that guides scavenging air in the hot elevator 28 to the dryer 1 is connected to the upper part of the hot elevator 28 . Further, the screen 2 is a vibrating screen equipped with a plurality of sieve screens 2a that sieve the aggregate A according to particle size, and below the vibrating screen, a plurality of vibrating screens each receive the aggregate A of each particle size sieved by each sieve screen 2a. Bins 2b each having a partition chamber are arranged in series, and the duct 27 for guiding scavenging air generated in the screen 2 to the dryer 1 is connected to the upper part of a screen cover 2c that covers the entire bin 2b. Furthermore, the aggregate measuring tank 3 is for weighing a predetermined amount of the aggregate A that has been sieved by the screen 2 according to particle size, and the aggregate A weighed here is supplied from the filler bin 32 and sent to the filler measuring tank. At 33, the filler B is fed into the mixer 4 together with a predetermined amount of filler B. Then, in the mixer 4, these aggregates A and filler B are stirred and mixed together with asphalt C sent from an asphalt tank 34, and an asphalt mixture is produced. Further, a dust cover 35 is provided on the upper part of the mixer 4 so as to cover the aggregate measuring tank 3 and the filler measuring tank 33,
The above-mentioned duct 27 that guides scavenging air generated in the aggregate measuring tank 3 and the mixer 4 to the dryer 1 is connected to the upper side surface of the dust cover 35 .

Note that the reference numeral 36 in the figure is a perforated plate.

Next, the operation of the present invention configured as described above will be explained.

FIG. 1 shows the operating state of the asphalt plant of the present invention. Cold aggregates A with different particle sizes are taken out from the aggregate hopper, conveyed together to the dryer 1 by the conveyor 10, and dried and heated by the burner 9. Ru. Next, this dry and heated aggregate A
The screen 2 is moved by the hot elevator 28.
After being transported to and classified according to particle size, a predetermined amount of the aggregate is weighed in an aggregate measuring tank 3, and stirred and mixed with filler B, asphalt C, etc. in a mixer 4 to produce an asphalt mixture.

Here, in the burner 9 of the dryer 1, in addition to the clean air supplied by the burner blower 19 as combustion air, the screen 2,
Scavenging air sent by an auxiliary blower 29 from the aggregate measuring tank 3, mixer 4 and hot elevator 28 is also utilized. That is, the clean air supplied by the burner blower 19 flows inside the casing 16 of the burner 9, is combusted together with the fuel injected from the fuel injection nozzle 17, and enters the dryer main body 8. In addition, the scavenging air generated in the screen 2, mixer 4, etc. is sent from the side to the air swirling chamber m of the dryer 1 by the auxiliary blower 29, while swirling around the outer periphery of the casing 16 of the burner 9 in the circumferential direction. It flows into the vicinity of the tip of the casing 16 and is burned. Then, the cold aggregate A enters the rotary furnace 5 of the dryer body 8 together with the combustion air from the burner 9 to dry and heat the cold aggregate A, and is discharged into the atmosphere from the chimney 11 by the exhaust fan 12 through the cyclone 14 and bag filter 15. .

In this way, the high-temperature scavenging air generated in the screen 2, mixer 4, etc. is used together with clean air as combustion air in the dryer 1, so the amount of clean air sent can be reduced by 25 to 30% compared to conventional methods. can. Furthermore, the amount of scavenging air sent and the amount of clean air sent can be adjusted in conjunction with each other by dampers 23 and 30. Furthermore, although the scavenging air contains dust and moisture, it is not guided directly into the burner 9 but into the air swirling chamber m, so the dust and moisture will not impair the function of the burner 9. .

By the way, the scavenging air does not necessarily need to be guided in its entirety to the dryer 1, and of course only a part of it, such as only the scavenging air of the screen 2, may be guided to the dryer 1.

As described above, in the asphalt plant of the present invention, the high-temperature scavenging air generated in the conveyor, screen, mixer, etc. is used as combustion air in the dryer, so the amount of clean air sent for combustion is It is possible to significantly reduce the capacity and power of the burner blower, and also reduce the capacity and power of the exhaust fan, as well as the capacity of the dust collector. In addition, the conveying device, screen, etc. are connected via a duct to a hood that is provided approximately concentrically with an air swirling chamber that opens at one end of the dryer body on the outer periphery of the air outlet of the burner casing. Scavenging air generated by the conveyor, screen, etc. is sent to the air swirling chamber by the auxiliary blower installed in the duct, and in the air swirling chamber, the combustion gas from the burner is turned into a swirling flow that is circulated inside the dryer main body. Because of the blow-in configuration, scavenging air as secondary air is effectively mixed with the combustion gas of the burner,
In addition to good combustion of the fuel, the swirling flow has the effect of improving the efficiency of drying and heating the cold aggregate. Furthermore, the suction action of the auxiliary blower prevents scavenging air containing dust from leaking to the outside, and the scavenging air does not come into direct contact with the combustion injection nozzle of the burner or attached devices such as electrode rods. This has the advantage that the burner is not affected by the dust contained in the scavenging air.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a schematic diagram of an asphalt plant, Fig. 2 is a side view of a dryer, Fig. 3 is an enlarged side view of a broken main part of the burner of the dryer, and Fig. 4 is a schematic diagram of an asphalt plant. 5 is a plan view of the same, FIG. 5 is a view taken along the - arrow in FIG. 3, and FIG. 6 is a sectional view taken along the - arrow in FIG. 1...Dryer, 2...Screen, 4...Mixer, 8...Dryer body, 9...Burner, 16
...Casing, 17...Combustion injection nozzle, 18
...Ignition device, 19...Burner blower, 22...
Control motor, 25...Hood, m...Air swirling chamber, 28...Hot elevator (transport device), 2
9...Auxiliary blower.

Claims (1)

[Scope of utility model registration request] The cold aggregate A is put into the dryer 1 and dried and heated by the burner 9. The dry and heated aggregate A is sent to the screen 2 by the conveying device 28 and sieved by particle size, and the sieved aggregate is passed to the mixer 14. In an asphalt plant where asphalt is mixed with asphalt etc. to form an asphalt mixture, it is equipped with a fuel injection nozzle 17 inside, an air blowing port 16a is opened at one end of the dryer body 8, and an air intake port 16b is installed.
A hood 25 is provided approximately concentrically on the outer periphery of the air outlet 16a of the casing 16 of the burner 9, which is connected to the burner blower 19, forming an air swirling chamber m that opens at one end of the dryer main body 8. and one or more of the conveying device 28, the screen 2, and the mixer 4 are connected to the hood 25 through ducts 26 and 27, and the ducts 26 and 27 are connected to the hood 25. An asphalt plant characterized in that an auxiliary blower 29 is provided for feeding scavenging air generated by the conveying device 28, the screen 2, and the mixer 4 into the dryer main body 8 through the swirling chamber m.