JPH07103531B2 - Sieving and storage equipment for aggregates in asphalt plants - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sieving and storing device for an asphalt plant, which stores heat-dried aggregate by sieving according to particle size.

[Prior Art] In a conventional asphalt plant, as shown in FIG. 4, aggregate dried by heating in a dryer is sifted by a vibrating sieve 1 into an aggregate storage bin 2 having a section arranged below the vibrating sieve 1. It is temporarily stored for each grain size. Then, according to the composition of the asphalt mixture to be produced, the discharge gates 3a, 3b, 3c, 3d of the aggregate storage bin 2 are opened to discharge the desired aggregate, and the aggregate is weighed by the weighing hopper 4 and charged into the mixer 5. Molten asphalt, stone powder, etc. are added and mixed and adjusted to produce an asphalt mixture.

By the way, in the asphalt plant, the aggregate is 25mm or more (oversize), 25-13mm, 13
It is common to sieve to 5 kinds of particle size of ~ 5mm, 5 ~ 2.5mm, 2.5mm or less. In this case, the mesh size 30 square hole (or round hole The sieve mesh 6a, the sieve mesh 6a having a mesh size of 15 mm in the lower stage, the sieve mesh 6 having a mesh size of 6 mm in the lower stage, and the sieve mesh 6d having a mesh size of 3 mm in the lower stage are arranged as described above. When the aggregate is sieved by the vibrating sieve 1 having a sieve mesh, the sand bottle 2a of the aggregate storage bin 2
Stored is the one having a particle size of 2.5 mm or less which has passed through the lowermost screen 6d of the vibrating screen 1. And what is stored in this sand pin 2a is used as a sand component for the production of the asphalt mixture.

In this way, since there is only one sand bottle in the aggregate storage bin of the conventional asphalt plant, it is supplied to the plant main unit despite being stocked separately from fine sand and coarse sand on the supply side. Then, fine sand and coarse sand are stored together in a sand bottle and are treated as sand of 2.5 mm or less.

[Problems to be Solved by the Invention] However, when a special asphalt mixture, for example, a fine-gap gap asphalt mixture is produced, fine sand stored in a sand bottle is required because sand having a grain size corresponding to fine sand is required. This method has a very annoying defect because the sand mixed with coarse sand is once extracted and fine sand is supplied and stored again in the sand bottle, or another bottle is prepared.

In addition, even when switching production of general mixtures such as coarse-grained, fine-grained, and fine-grained asphalt mixture, those with a fine sand and coarse sand particle size blend supplied in the sand bottle at the blending ratio of the previously produced blend Remained, and had the drawback of adversely affecting the quality of the asphalt mixture produced until this residue was used up.

Therefore, in view of the above points, the present invention has a structure capable of separately storing coarse particles and fine particles of sand in a sand bottle,
A special asphalt mixture can also be produced, and it is intended to produce a high-quality product by adjusting the amount of coarse and fine sand particles mixed during the production of the asphalt mixture. .

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention stores a vibrating sieve that sifts heat-dried aggregate with a particle size, and an aggregate that is sieved with the vibrating screen according to particle size. In an aggregate sieving storage device in an asphalt plant consisting of aggregate storage bins having compartments, a sand storage is provided by arranging a partition plate inside the aggregate storage bin in a direction orthogonal to the aggregate flow of the vibrating sieve. The bin is divided into two chambers, one for coarse grains and one for fine grains, and is inclined above the partition plate of the sand bottle in the inclination direction of the screen of the vibrating sieve, and in the same direction as the aggregate flow of the vibrating sieve. A distribution chute equipped with a drive device that can move horizontally along the bottommost screen of the vibrating screen is arranged, and the distribution chute is arranged to maintain an appropriate amount of coarse particles and fine particles in the two chambers. To detect the storage amount in the sand bottle. It is characterized by having a control unit that moves horizontally according to the detection value of the instrument.

[Operation] According to the aggregate sieving / storing device in the asphalt plant according to the present invention, when the aggregate heated and dried by the dryer is put into the vibrating sieve, the aggregate is sieved one after another by the sieve mesh and stored according to the particle size. Go. The sand that reaches the bottom sieve mesh is sieved while flowing down the sieve mesh, fine sand is sieved to the input side, coarse sand is sieved at a position close to the discharge side, and passes through the mesh. Then, they are dropped and stored in the sand bottles divided into two chambers below the sieve screen.

At this time, if the amount of aggregate supplied to the vibrating screen is small, the screen efficiency of the vibrating screen is improved and a large amount of fine particles are stored in the sand bottle on the input side. When the supply amount is large, the sieving efficiency of the vibrating screen is reduced and a small amount of fine particles is stored in the sand bottle on the input side. For this reason,
The level meter installed in the sand bottle detects the storage amount of sand (for example, when the storage capacity of the sand bottle on the input side is small), the distribution chute is placed on the input side when the rate of increase is large. When the increase rate of the stored amount is small, the distribution chute is moved to the discharge side so that the increase rate of the stored amount is increased. By moving the distribution chute in this manner, an appropriate amount of sand is stored in each of the two sand bins.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, 11 is a vibrating sieve mounted on the uppermost part of a mixing tower of an asphalt plant. The vibrating sieve heated and dried by a dryer is lifted by a vertical transfer device and charged from a charging chute 12 to generate vibration. The vibration generated by the body 13 screens the particles according to their particle size. The vibrating screen 11 is provided with several stages of screens, and Fig. 2 shows an example of the arrangement of the screens. In particular, care should be taken to improve the screening efficiency of sand. At the position facing the uppermost charging chute 12 of the vibrating screen 11, a mesh screen 11a with square holes (or round holes) with a mesh size of 16 mm, followed by a mesh size 2
5 mm sieve mesh 11b, and a mesh size 6 mm sieve mesh 11c in the lower stage,
This is followed by a sieve mesh 11d with a mesh size of 16 mm, a sieve mesh 11e with a mesh size of 3 mm in the lower row, and then a mesh size of 6 mm.
No. 11f and a mesh net 3g with a mesh size of 3 mm are placed at the bottom, and a sieve mesh with a mesh size of 3 mm is placed at the bottom side and the upper side of the loading side to sort the sand. The division efficiency is improved.

Below the vibrating screen 11, an aggregate storage bin 14 provided with compartments is arranged so that the aggregate screened by the vibrating screen 11 can be stored according to particle size. Furthermore, a partition plate 15 is provided at an appropriate position in a direction orthogonal to the aggregate flow of the vibrating screen 11 inside the sand bottle located below the lowermost screen of the vibrating screen 11 to divide it into two chambers. Fine grain sand bottle 14a for storing fine grains and a coarse grain sand bottle 14b for storing coarse grains of sand are formed, for example, the storage capacity of the fine grain sand bottle 14a is 20%, It is advisable to partition so that the storage capacity of the grain sand bottle 14b is about 80%. Then, a level meter 16 for continuously detecting the storage amount of sand is installed in the sand bottle 14a having a small storage capacity. It should be noted that this level meter may be a level meter for one-point level detection instead of a continuous level meter, and if it is this kind of level meter, a plurality of level meters are provided on the side wall of the sand bottle 14a at appropriate intervals.

Reference numeral 17 denotes a distribution chute disposed above the partition plate 15, and the distribution chute 17 is inclined in the same direction as the slanting direction of the sieve mesh, and is sieved by the lowermost sieve mesh and dropped into the sand bottle 14a. The vibrating screen 11 is for adjusting the amount of fine particles of sand to be used.
It is possible to move horizontally in the same direction as the aggregate flow, and the upper end of the distribution chute 17 is movable from the vicinity of the input end of the screen to the upper part of the partition plate 15 by the drive of the drive device 18. The sand dropped on 17 slides down on the chute and is put into the sand bottle 14b.

The distribution chute 17 is linked with the level meter 16,
The storage amount of the sand bottle 14a is detected by the level meter 16, and this detection signal is taken into the control unit 19. The control unit 19 controls the movement of the distribution chute 17 by driving the drive device 18 according to the storage amount of the sand bottle 14a or the increase rate of the storage amount, and the storage amount and storage of the sand in the sand bottle 14a. If the rate of increase in the amount is large, the distribution chute 17 is moved in the direction A to reduce the amount of sand falling into the sand bottle 14a, and if the rate of increase in the amount of sand stored in the sand bottle 14a is small, the distribution chute 17 is moved. It is moved in the B direction to increase the amount of sand falling into the sand bottle 14a.

Further, a level meter (not shown) for measuring the storage amount is also provided in the sand bottle 14b having a large storage capacity, and the aggregate supply amount to the dryer is controlled based on the detection value of the level meter. It is preferable that the aggregate is supplied in proportion to the amount of the aggregate used.

Aggregates with a larger grain size than the sand stored in the sand bottles 14a, 14b are sequentially stored in the aggregate bins 14c, 14d, 14e. 20a, 20b, 2
0c, 20d, and 20e are discharge gates provided at the bottom of each bin.

Below the sand bottles 14a, 14b of the aggregate storage bin 14, a sand weighing hopper 21 for exclusive use of sand is provided, and the amount of sand mixed in the asphalt mixture is more precisely measured and managed to improve quality. It is designed to work. Further, an aggregate weighing hopper 22 similar to the conventional one is disposed below the aggregate bins 14a, 14d, 14e,
A mixer 23 for mixing the materials is arranged below it.

Then, when the aggregate heated and dried by the dryer of the asphalt plant is lifted up to the upper part of the mixing tower and charged into the vibrating sieve 11 from the charging chute 12, the sand in the aggregate has coarse mesh screens 11a and 11c. One after another and falls.
Then, most of the sand falls on the sieve mesh 11e of the smallest mesh arranged on the input side of the aggregate. The sand particles having a relatively small particle size that have reached the sieve net 11e are quickly sieved, and most of them pass through the mesh of the sieve net 11e and are closer to the aggregate loading on the smallest sieve mesh 11g. Fall to the position. On the other hand, most of the sand with a large particle size has a short length of the sieve mesh 11e, so that it does not pass through the mesh and is sent to the adjacent downstream sieve mesh 11f having a mesh size and then sieved off.

Inside the sand bin 14a for fine granules, which has passed through the smallest mesh screen 11e and has reached the bottommost screen mesh 11g, and which has a particularly small particle size, is screened out early and is closer to the side where the aggregate is input. To fall. Most of the sand that has reached the material input side of the sieve mesh 11g at the lowermost stage is sieved off near the central portion in the length direction of the sieve mesh 11g toward the discharge part, and falls into the coarse grain sand bottle 14b.

Therefore, fine-grained sand is stored in the fine-grained sand bottle 14a close to the aggregate input side of the sand bin that stores sand with a grain size of 2.5 mm or less, and the coarse-grained sand bottle 14b has a relatively large grain size. The sand will be stored.

However, for example, when the aggregate supply amount to the dryer is 40 to
When the supply capacity fluctuates as much as 100 tons / hour, the sieving efficiency of the vibrating screen 11 also fluctuates greatly due to the fluctuation of the supply amount. For example, if the aggregate supply rate is 40 tons / hour, the sieving efficiency will be good and a large amount of sand will be stored in the sand bottle 14a, and if the aggregate supply rate is 100 tons / hour. It is possible that the sieving efficiency is poor and only a small amount of sand is stored in the sand bottle 14a.

Therefore, the level meter 16 inserted in the fine grain sand bottle 14a sequentially detects the amount of stored sand and takes it into the control unit 19, and when it is determined that the increase rate is large, the distribution chute 17 is moved toward the loading side (direction A). The driving device 18 is controlled so as to move to (1) to reduce the amount of sand input to the sand bottle 14a. When it is determined that the rate of increase is small, the drive device 18 is drive-controlled to move the distribution chute 17 in the discharge side direction (direction B), and the amount of sand input to the sand bottle 14a is increased. By appropriately moving the distribution chute 17 in this way, the amount of fine-grained sand input to the sand bottle 14a is appropriately maintained.

Then, the sand stored in the fine-grain sand bottle 14a and the coarse-grain sand bottle 14b is dispensed in a predetermined amount according to the composition of the asphalt mixture and is cumulatively measured by the sand weighing hopper 21, and further the aggregate bins 14c, 14
Desired aggregates are dispensed from d and 14e, a predetermined amount is measured by an aggregate weighing hopper 22, dispensed to the mixer 23, and asphalt is sprayed and mixed to produce an asphalt mixture.

FIG. 3 shows another embodiment, in which the same components as those in FIG. 1 are designated by the same reference numerals. The changed portion is the position of the partition plate 15 of the sand bottle, and for example, it is divided so that the storage capacity of the fine grain sand bottle 14a is 80% and the storage capacity of the coarse grain sand bottle 14b is about 20%. However, it is better to use this for plants that often ship special asphalt mixtures that require a large amount of fine-grained sand. And, the arrangement of the screen of the vibrating screen 11 in this case is the same as the conventional one, and the level meter 16 is arranged in the coarse grain sand bottle 14b, and the distribution chute 17 is arranged according to the storage amount in the coarse grain sand bottle 14b. Is controlled to move, and the control method is the same as that described in the first embodiment.

In the above description, the movement control of the distribution chute 17 is automatically performed in conjunction with the level meter 16, but it is not limited to any automatic control, and the level meter 16
The storage amount detected by is displayed on the monitor on the operation panel,
The operator monitors the storage amount and manually distributes the chute.
The 17 may be moved.

[Effects of the Invention] As described above, the aggregate sieving and storing device in the asphalt plant according to the present invention has a preferable structure capable of separately storing coarse particles and fine particles of sand in a sand bottle. ,
Even if there is a change in the amount of aggregate supply or a change in the sieving efficiency of the screen, the distribution chute is moved horizontally along the lowermost screen, and the coarse particles in the sand falling from the screen are coarse particles. Since the proper amount can be quickly distributed and stored in the two chambers that divide the fine and fine particles, it is possible to adjust the mixing amount of the coarse and fine particles of sand when manufacturing the asphalt mixture. Good products can be manufactured. Further, it becomes possible to manufacture a special asphalt mixture, and it is possible to cope with the production of a wide variety of asphalt mixtures.

[Brief description of drawings]

FIG. 1 is a schematic front view in which a part of an aggregate sieving and storing device in an asphalt plant according to the present invention is longitudinally cut, and FIG. 2 is a diagram for explaining the arrangement of a sieve mesh of the vibrating sieve of FIG. 1, 3
FIG. 4 is a schematic front view of a part of another embodiment of the aggregate sieving / storing device, and FIG. 4 is a schematic front view of a part of a conventional aggregate sieving / storing device. 11 ... Vibrating screen, 12 ... Input chute, 14 ... Aggregate storage bin, 14
a… Fine grain sand bottle, 14b… Coarse grain sand bottle, 15… Partition plate, 16
... Level meter, 17 ... Distribution chute, 18 ... Driving device, 19 ... Control part, 21 ... Sand weighing hopper, 22 ... Aggregate weighing hopper, 23 ... Mixer

Claims (1)

[Claims] 1. An aggregate in an asphalt plant comprising a vibrating sieve for sieving aggregate dried by heating with a dryer, and an aggregate storage bottle having a compartment for storing the aggregate sieved by the oscillating sieve according to grain size. In the sieving storage device, the sand storage bin is divided into two chambers, one for coarse grains and one for fine grains, by disposing a partition plate inside the aggregate storage bin in a direction orthogonal to the aggregate flow of the vibrating sieve. The upper part of the partition plate of the sand bottle is inclined in the slanting direction of the screen of the vibrating screen, and can be horizontally moved along the bottom screen of the vibrating screen in the same direction as the aggregate flow of the vibrating screen. Distributing chute equipped with a driving device for detecting the storage amount in the sand bottle of the distribution chute so as to maintain an appropriate amount of coarse particles and fine particles in the two chambers. It has a control unit to move horizontally by Sieving storage device of the aggregate in the asphalt plant, wherein.