JPH0528281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for producing asphalt mixture and ready-mixed concrete, which are road paving materials.

[Prior Art] Conventionally, asphalt mixture was produced in an asphalt plant, and ready-mixed concrete was produced in a batcher plant, each of which had its own dedicated plant. Asphalt mixture is exclusively used as road paving material, but this is because concrete pavement has various drawbacks such as a long curing period. In recent years, compacted concrete pavement has been developed to overcome the drawbacks of concrete pavement.This compacted concrete pavement consists of leveling cement concrete with zero slump on the road and leveling it with vibrating rollers. This is a paving method that can significantly shorten the curing period, enable early opening, and has the advantage that a paving machine for asphalt mixture can be used as is.

[Problem to be solved by the invention] However, if road paving is to be done using both asphalt concrete and cement concrete, it is necessary to have both an asphalt plant and a butcher plant. has a large economic burden. Considering this economical aspect, we believe it is desirable to construct a single plant that has both functions. Therefore, in the present invention, both asphalt concrete and cement concrete use aggregate whose particle size is controlled, and the difference is that asphalt concrete uses asphalt and stone powder, whereas cement concrete uses aggregate with controlled particle size. The purpose of this project is to propose a device that can also produce asphalt mixture and ready-mixed concrete using the equipment for manufacturing asphalt mixture as the basic equipment, focusing on the fact that it only requires mixing cement, water, and admixtures. be.

[Means for Solving the Problems] In view of the above-mentioned points, in order to solve the above-mentioned problems, the present invention has an asphalt injection nozzle inserted into the lower end of an aggregate heating and mixing drum which is rotatably supported at an angle. An aggregate measuring tank, a cement measuring tank and a water measuring tank for measuring cement and water, which are mixed materials for fresh concrete, are arranged below the cold hopper, and a mixer is arranged below the measuring tank, while a mixer is arranged below the drum. A blower is installed to send cooling air into the drum from approximately the center, and an exhaust flue is connected to the cold hopper to exhaust the exhaust gas. A predetermined amount of aggregate and stone powder with a diameter of Aggregates of various particle sizes are cut out according to the mix of ready-mixed concrete to be shipped during the production of ready-mixed concrete.
The aggregate is fed into the drum for heating and mixing while being weighed, and heated at a relatively low temperature in the front half of the drum to bring it to a surface dry state where only the surface water of the aggregate evaporates, and in the rear half of the drum near the center of the drum. After cooling the heated aggregate with cooling air sent in from the drum, it is discharged from the drum at the appropriate time and weighed in a predetermined amount in an aggregate measuring tank.
Cement measured in cement measuring tank, water measuring tank,
The present invention provides a method for producing asphalt mixture and ready-mixed concrete, characterized in that the asphalt mixture and ready-mixed concrete are mixed and prepared by adding the mixture to a mixer with water.

Furthermore, the present invention has an aggregate measuring tank in which an asphalt injection nozzle is inserted, and cement and water, which are mixed materials for ready-mixed concrete, are measured in a cold hopper at the lower end of the aggregate heating drum which is rotatably supported at an angle. A cement measuring tank and a water measuring tank are provided, and a mixer is provided below the measuring tank, and through holes are bored at appropriate intervals along the peripheral wall near the center of the drum. The asphalt is surrounded from the outer periphery by a cover body, a blower for feeding cooling air into the drum is connected to the cover body, and an exhaust flue for guiding exhaust gas to a downstream dust collector is connected to the cold hopper. The company provides mixed lumber and ready-mixed concrete manufacturing equipment.

[Function] According to the present invention, when producing asphalt mixture, aggregate (crushed stone, sand) and stone powder are cut out in an appropriate ratio according to the composition of the asphalt mixture to be shipped, and a drum for heating and mixing the aggregate is cut out. Each material is heated by high-temperature gas passing through the drum, and asphalt is injected into each material from an asphalt injection nozzle installed inside the ram, causing each material to roll through the drum. The mixture is mixed and prepared while flowing down the drum, and is discharged as an asphalt mixture from the cold hopper side at the lower end of the drum. In addition, when producing ready-mixed concrete,
Aggregates (crushed stone, sand) are cut out according to the mix of ready-mixed concrete to be shipped, and fed to the aggregate heating and mixing drum while being weighed. At this time, the key point is not to heat the aggregate in the drum to raise its temperature, but to send in hot air to the extent that only the surface water adhering to the surface of the aggregate evaporates. In other words, it is preferable that the surface of the aggregate is free of moisture and the internal voids are filled with water, a so-called surface dry condition.
The aggregate, which is heated in the front half of the drum by the hot air from the burner and becomes surface dry, is heated to a temperature suitable for mixing ready-mixed concrete in the rear half of the drum by cooling air sent from near the center of the drum. It is cooled and temporarily stored in the lower part of the cold hopper, then weighed at the appropriate time in the aggregate measuring tank in the lower part of the cold hopper, and then put into a mixer together with the cement and water weighed in the cement measuring tank and water measuring tank, and mixed for a predetermined period of time to produce ready-mixed concrete. is manufactured.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

Reference numeral 1 denotes a dryer for heating and mixing aggregate, in which a cylindrical drum 3 having a number of scraping blades 2 arranged around its inner periphery is rotatably and tiltedly supported, and is moved at a predetermined position by a drive device (not shown). It is rotating at a speed of . A burner 5 is connected to the upper end of the drum 3 via a combustion chamber 4.
An exhaust flue 8 equipped with a cold hopper 6 and a damper 7 for adjusting air volume is connected to the lower end of the drum 3, and the downstream side of the exhaust flue 8 captures scattered dust. A dust collector 9, an exhaust fan 10 for gas suction, and a chimney 11 are provided. Through-holes 12 are bored at appropriate intervals in the peripheral wall near the center of the drum 3, and the through-holes 12 are surrounded by a cover body 13 which is fixed and separated from the drum 3 from the outer circumference. 13 is connected to a blower 14 that sends cooling air through the through hole 12 and into the drum 3, and a damper 1 for adjusting air volume.
5 allows adjustment of the amount of cooling air sent.

Aggregate hoppers 16a to 16d store aggregate according to particle size. A variable speed feeder 17 disposed below each aggregate hopper cuts out a predetermined amount of aggregate, and the aggregate is weighed by a weighing conveyor 18 while being conveyed. 1
It is supplied into the drum 3 via 9 and 20. Reference numeral 21 is a stone powder storage bin for storing stone powder, which is one of the materials for asphalt mixture. ,
It is supplied into the drum 3 together with the aggregate. 24 is an asphalt injection nozzle that injects asphalt into the aggregate supplied into the drum 3 during the production of asphalt mixture, and the asphalt supply pipe 2
5 to an asphalt tank (not shown). Reference numeral 26 is an aggregate measuring tank disposed below the discharge gate 27 of the cold hopper 6, which measures the aggregate that has passed through the drum 3 and is temporarily stored in the lower part of the cold hopper 6. Reference numeral 28 is a cement measuring tank for measuring cement, which is one of the raw materials for fresh concrete, and temporarily stores the cement taken out from a cement storage silo (not shown) in a cement storage bin 29. The cement stored in the container is dispensed, weighed in a predetermined amount, and placed into a mixer 31 by a screw feeder 30. Reference numeral 32 denotes a water measuring tank for measuring the water used during the production of fresh concrete. Water is supplied from a water tank 33 disposed above, measured a predetermined amount, and then poured into the mixer 31 by a pump 34. Further, an admixture measuring tank (not shown) is arranged above the water measuring tank 32, and a predetermined amount of the admixture is put into the water measuring tank 32 and mixed with water for use. The mixer 31 is a two-shaft mixer capable of kneading both asphalt mixture and fresh concrete, and the two kneading shafts 35 arranged in parallel between the opposing side walls of the kneading tank are moved in opposite directions. Rotate it to
The kneading blades 36 attached to the kneading shaft 35 scrape up the kneaded material and move it along the axial direction for kneading. This type of twin-shaft mixer is used in both asphalt and batcher plants, and although there are slight differences in the shaft seal, arrangement of mixing blades, shape, etc., it mixes both asphalt mixture and ready-mixed concrete. It is possible to construct a twin-screw mixer that can mix both materials.

Therefore, when producing asphalt mixture, predetermined aggregates (crushed stone, crushed stone,
A predetermined amount of sand) is delivered by the variable speed feeder 17, a predetermined amount of stone powder is delivered from the stone powder storage bin 21 by the variable speed feeder 22, and the conveyors 19, 20 are weighed by the weighing conveyors 18, 23. It is supplied into the drum 3 through the drum 3. The aggregate supplied into the drum 3 is heated by hot air from the burner 5 in the front half of the drum 3, and asphalt is injected into it from the asphalt injection nozzle 24, and the aggregate is rolled inside the drum 3 in the rear half of the drum 3. While flowing down, the mixture is adjusted and temporarily stored in the lower part of the cold hopper 6, and is discharged as an asphalt mixture by opening and closing the discharge gate 27. At this time, the aggregate measuring tank 26 and the mixer 3
If it is not necessary to measure and mix the asphalt mixture in step 1, the aggregate measuring tank 26 and mixer 31 are made horizontally movable so that the discharged asphalt mixture does not pass through the aggregate measuring tank 26 and mixer 31. You can leave it as is. In this case, the mixer 31 may be one that can mix only fresh concrete. In addition, an asphalt injection nozzle is arranged in the mixer 31, and after a predetermined amount of aggregate heated and dried in the drum 3 is weighed in the aggregate measuring tank 26, the mixer 31
It is also possible to produce an asphalt mixture by injecting a predetermined amount of asphalt into the mixture and adjusting the kneading with the mixer 31.

When manufacturing ready-mixed concrete, aggregate hopper 16a to
From 16d, a predetermined amount of aggregate is cut out by a variable speed feeder 17, and fed into the drum 3 via conveyors 19 and 20 while being weighed by a weighing conveyor 18. Although it is heated, the aggregate is not heated to a high temperature as in the production of asphalt mixture described above. In concrete, the water/cement ratio is an important factor that determines the strength and slump value of concrete, and it is no exaggeration to say that controlling the moisture content of aggregate is the most important factor when producing fresh concrete. Therefore, always measure the surface water content of the aggregate,
It goes without saying that the desired water/cement ratio cannot be achieved unless the amount of surface water adhering to the surface of the aggregate is calculated and the amount of water obtained by subtracting the amount of surface water from the amount of water in the mixing design is used as the mixing water. However, it is impossible to constantly sample the surface water percentage of aggregates and feed back this surface water percentage to reflect it in water measurement value correction.

Therefore, we changed our thinking and evaporated the surface water of the aggregate, creating a state where there is no moisture on the surface of the aggregate and only the internal voids are filled with water, a so-called surface dry state. There is no need to constantly sample the moisture content, and we think that subsequent moisture management will be easier. Therefore, when heating the aggregates in the drum 3, the burner 5 is designed to evaporate only the water adhering to the surface of the aggregates and send relatively low-temperature hot air so that the aggregates are surface-dry. It is necessary to control the amount of combustion. It is thought that this combustion amount control can be controlled if information such as the amount of aggregate supplied, the surface water rate, and the temperature of aggregate discharged from the dryer can be obtained. However, if the surface water percentage fluctuates greatly, it may not be possible to always maintain a surface dry state even during continuous operation, but if the aggregate can be maintained near a surface dry state, the surface water It is thought that more severe moisture management can be achieved than the method of occasionally sampling and measuring the water rate and providing feedback to the measured water value.

The temperature of the aggregate that has been heated by hot air in the front half of the drum 3 to a surface-dry state has reached a certain level, and is unsuitable for use in the production of ready-mixed concrete, for example, when it is added during mixing. Cooling air is blown from near the center of the drum 3 by the blower 14 to avoid evaporating some of the water and raising the temperature of fresh concrete during mixing, which will have a negative impact on the production of high-quality concrete. The air volume is adjusted by the air volume adjustment damper 15, and the air is fed into the drum 3, mixed with the hot air passing through the drum 3, and the heated aggregate is heated in the rear part of the drum 3 so that the low temperature gas flows through the rear part of the drum 3. The temperature of the aggregate is reduced to the desired temperature during the passage of the aggregate. Then, this aggregate is temporarily stored in the lower part of the cold hopper 6, and the discharge gate 27 is opened and closed at appropriate times to discharge the aggregate downward, and a predetermined amount is measured in the aggregate measuring tank 26 and thrown into the mixer 31.
A predetermined amount of cement measured in the cement measuring tank 28 is put into the mixer 31 by the screw feeder 30, and the amount of water according to the mixing design is measured in the water measuring tank 32 (the aggregate is in a dry state and the surface There is no particular need to correct the water rate, but just in case, use cold hopper 6.
(The surface water content may be corrected by sampling the aggregate of It is.

It is most preferable to heat the aggregate in the dryer 1 so that it becomes surface-dry, but since it is practically impossible to detect this state, it is preferable to heat the aggregate in a wet state so that the temperature does not rise too much. Since the desired purpose can be achieved to some extent by heating the sand to a degree that does not deviate from the purpose of the present invention, the present invention does not include combustion management within the scope of the purpose of the present invention. be.

[Effects of the invention] As described above, in the present invention, both asphalt mixture and ready-mixed concrete can be produced in a single plant, so the initial cost of the plant is low and there are great economic merits. It is something.

In addition, when producing ready-mixed concrete, the wet aggregate is heated in a dryer to bring it close to a surface-dry state in which the surface water evaporates, so the water/cement ratio, which is an important factor in concrete, becomes more severe. It is something that can be managed.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of the device of the present invention;
FIG. 2 is an enlarged sectional view taken along the line A--A in FIG. 1. 1... Dryer, 2... Scraping blade, 3...
Drum, 5...burner, 6...cold hopper,
8... Exhaust flue, 9... Dust collector, 12... Through hole,
13...Cover body, 14...Blower, 16a-1
6d... Aggregate hopper, 24... Asphalt injection nozzle, 26... Aggregate measuring tank, 28... Cement measuring tank, 31... Mixer, 32... Water measuring tank.

Claims (1)

[Scope of Claims] 1. An aggregate measuring tank and cement and water, which are mixed materials for fresh concrete, are installed below the cold hopper at the lower end of the drum for heating and mixing aggregates, which is rotatably tilted and pivoted into which an asphalt injection nozzle is inserted. A cement measuring tank and a water measuring tank are arranged to measure the amount of water, a mixer is arranged below the measuring tank, and a blower is arranged to send cooling air into the drum from approximately the center of the drum. An exhaust flue for exhausting exhaust gas is connected to the cold hopper, and when manufacturing asphalt mixture, a predetermined amount of aggregate and stone powder of various particle sizes is cut out according to the composition of the asphalt mixture to be shipped, and a drum is used to heat and mix the aggregate while weighing it. The aggregate is heated to a high temperature in the drum, and a predetermined amount of asphalt is injected into the heated aggregate.
The mixture is adjusted while it tumbles down the drum, and when producing ready-mixed concrete, aggregates of various particle sizes are cut out according to the mix of ready-mixed concrete to be shipped, and fed to the aggregate heating and mixing drum while being weighed. In the first half of the drum, the aggregate is heated at a relatively low temperature to bring it to a surface dry state where only the surface water of the aggregate evaporates, and in the second half of the drum, the heated aggregate is cooled with cooling air sent from near the center of the drum. An asphalt mixture is characterized in that it is timely discharged from a drum, measured in a predetermined amount in an aggregate measuring tank, and then put into a mixer together with cement and water measured in a cement measuring tank and a water measuring tank to mix and adjust. Fresh concrete manufacturing method. 2. An aggregate measuring tank in which an asphalt injection nozzle is inserted and below the cold hopper at the lower end of the rotatably tilted aggregate heating and mixing drum, and a cement measuring tank for measuring cement and water, which are mixed materials for fresh concrete. , a water measuring tank is disposed, and a mixer is disposed below the measuring tank, while through holes are bored at appropriate intervals along the peripheral wall near the center of the drum, and the through holes are inserted into the outer peripheral part of the drum. An asphalt composite material characterized in that the drum is surrounded by a cover body, a blower for feeding cooling air into the drum is connected to the cover body, and an exhaust flue is connected to the cold hopper for guiding exhaust gas to a downstream dust collector. Fresh concrete production equipment.