JP4261687B2 - Aggregate input device for ready-mixed concrete plant - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an aggregate feeding device that is effective when feeding aggregate into a drum of a mixer, particularly in a ready-mixed concrete plant equipped with a variable speed mixer.
[0002]
[Prior art]
The present applicant has filed Japanese Patent Application Laid-Open No. 61-207764 and Japanese Patent Application Laid-Open No. 8-19685 as proposals regarding mixers for mixing ready-mixed concrete. These proposals relate to variable speed mixers that can increase or decrease the number of rotations of the stirring blades, and are particularly characterized in that high-quality ready-mixed concrete can be obtained quickly and at low cost. According to it, when mixing various kneading materials into the drum and kneading ready-mixed concrete, first, water, cement and sand are added to knead good quality mortar, and then gravel is added to finish ready-mixed concrete. In the method, the rotation speed (best stirring blade peripheral speed) suitable for each step of mortar, ready-mixed concrete, and discharge is set. However, the load of the stirring blades temporarily increases when various kneading materials are charged, especially when aggregates such as gravel and sand are charged. This point will be described in detail with reference to FIG. The ready-mixed concrete plant has a storage bin 1 for storing materials such as sand, gravel, cement, etc., which are kneaded materials of ready-mixed concrete, a measuring instrument 2 for measuring each material in each storing bin, and each measuring instrument. The charging chutes 4 for guiding the materials weighed in (1) into the drum of the variable speed mixer 3 at the optimum timing are arranged in series. Accordingly, each material measured by the measuring instrument 2 is introduced into the drum of the variable speed mixer 3 by gravity through the chute 4.
[0003]
In a typical ready-mixed concrete plant equipped with a variable speed mixer capable of kneading 1.5 m ^{3 at a} time, the vertical distance from the axis of the rotating shaft of the stirring blade of the variable speed mixer 3 to the upper end of the meter 2 is about 4 m. The weight of aggregate to be charged at one time is about 1200 kg for sand and about 1500 kg for gravel. Since all of sand and gravel are charged in a short time of about 5 seconds, in the conventional aggregate charging device composed only of the charging chute 4, the impact force received by the stirring blade when the aggregate is charged In addition, since the aggregate input through the input chute 4 enters a piled state at one place, the load torque of the mixer temporarily increases in order to uniformly disperse the aggregate in the drum. According to the proposal, the load can be dealt with by quickly responding to this load and lowering the rotation speed of the stirring blade.
[0004]
[Problems to be solved by the invention]
However, even if temporarily, the rotational speed of the mixer is below the optimum peripheral speed of the stirring blade, leading to an increase in the kneading time.
The present invention, when producing ready-mixed concrete using a variable speed mixer, relieves the temporary load generated at the time of charging the aggregate, and kneads at the best stirring blade peripheral speed to produce high-quality ready-made concrete in a shorter time. It aims at providing the aggregate input device of the ready-mixed concrete plant which manufactures.
[0005]
[Means for Solving the Problems]
The present invention provides an aggregate feeding device that guides an aggregate measured by a measuring instrument of a ready-mixed concrete plant including a variable speed mixer capable of increasing or decreasing the number of rotations of a stirring blade into a drum of the variable speed mixer. In the apparatus provided with the fall energy buffer means which buffers the fall energy of the aggregate at the time of flowing out from the vessel. That is, the falling energy buffer means buffers and attenuates the falling energy of the aggregate flowing out from the measuring instrument using physical means when the aggregate measured by the measuring instrument is put into the variable speed mixer, and further the aggregate. Is dispersed in the drum, and the load of the variable speed mixer is reduced. Therefore, even when the aggregate is charged, the ready-mixed concrete is kneaded at a rotational speed closer to the best peripheral speed of the stirring blade.
This will be described in detail based on the explanatory diagram showing the load torque, power, and rotation speed of the variable speed mixer shown in FIG. For example, taking the second step as an example, when gravel, which is coarse aggregate, is thrown into the drum with the conventional aggregate throwing device, the load torque of the variable speed mixer rises rapidly as shown in FIG. The number of revolutions is greatly reduced as indicated by Na in the figure so as not to exceed the constant power value H1. The aggregate charging device of the present invention reduces the electric power of the motor from Ha to Hb by lowering the load of the variable speed mixer at the time of charging the aggregate as indicated by Tb in the figure, and the rotation speed of the stirring blade is Nb in the figure. In this way, the kneading is carried out in an approaching state at an optimum rotational speed.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, when producing ready-mixed concrete using a variable speed mixer, sand (fine aggregate), cement and water, which are raw materials of mortar, are put into a drum and the mortar is kneaded, and then gravel (coarse aggregate). This is an aggregate input device that is particularly effective for inputting aggregate when mixing ready-mixed concrete.
Embodiments of the present invention will be described below with reference to the drawings.
[0007]
[Example 1]
FIG. 2 is a schematic diagram showing a weighing unit and a mixer unit of a ready-mixed concrete plant equipped with a variable speed mixer according to the first embodiment of the present invention. An Example demonstrates the measurement and discharge | release of gravel which is a coarse aggregate.
In FIG. 2, the fall energy buffer means 7 of the first embodiment includes a storage tank 5 for temporarily storing gravel discharged from the gravel meter 2G, and gravel stored in the storage tank at the lower end of the storage tank 5. And discharging means 6 for feeding the liquid into the drum. The storage tank 5 is disposed between the measuring instrument 2G and the mixer 3, and is as close to the mixer 3 as possible. With this storage tank 5, gravel that had fallen from a height of about 3.5 m in the past will be dropped from a height of about 2.5 m, and the gravel fall energy will be reduced to about 70%. The maximum mixer load that sometimes occurs is also reduced by about 70%. Moreover, since the discharge | release means 6 of a present Example is formed in the structure which rotates the bottom cover of the storage tank 5 centering on a pin, when throwing the gravel stored in the storage tank into a drum, a storage tank The bottom cover 5 rotates and is put into the drum through a space formed by the bottom cover and the side wall of the storage tank. At this time, since the gravel also flows in the left and right direction of the bottom lid, the gravel is dispersed in the drum. Therefore, the load torque of the mixer when the gravel is charged further decreases.
[0008]
Moreover, the automatic metering system in the conventional ready-mixed concrete plant was made as follows. That is, for ready-mixed concrete, it is desirable to shorten the time from the start of kneading to placing as much as possible, and it is necessary to minimize the kneading time from the start of kneading to discharging. If kneading is started when one of the kneaded materials is insufficient and the metering is not completed, the remaining one metering is completed and the time until it is put into the mixer is wasted for the ready-mixed concrete. In order to prevent this, weigh all materials before starting kneading, put each material into the drum sequentially at the optimal timing, and weigh the next batch after all the materials are put into each meter. It was a way to get started. However, in this method, the gravel is metered only after the release of gravel in the second step is completed, so that the measurement of the next batch can be started. Therefore, the discharge of the third step is completed and the kneading of the next batch can be started. Even if it became a state, the measurement of gravel was not completed and the situation that kneading could not be started had occurred. However, the aggregate input device of the present embodiment has a structure in which the gravel measured by the measuring instrument 2G can be temporarily stored in the storage tank 5, and immediately after the start of kneading, the gravel of the measuring instrument 2G is discharged into the storage tank. Batch weighing can be started and weighing cycle time is greatly reduced. Accordingly, the kneading cycle of the ready-mixed concrete plant can be shortened and the shipping capacity can be greatly improved.
In the present embodiment, the case of gravel which is coarse aggregate has been described. However, when this means is used for the sand input device which is fine aggregate, the temporary load in the first step in FIG. 1 is greatly reduced. Can do.
[0009]
FIG. 3 shows a reference example. FIG. 3 is a schematic diagram showing only a portion corresponding to a portion for guiding gravel in the gravel meter 2G of FIG. The fall energy buffer means 7 includes a chute 8 for guiding gravel discharged from the gravel meter 2G into the drum, and a plurality of direction changing members 9 disposed on the chute and changing the flow direction of the aggregate in the chute. And a space 10 through which gravel flows out is provided between the lowermost direction changing member 9 and the lower end of the side wall of the chute 8. When the gravel discharged from the gravel meter 2G slides down the side wall of the chute 8, the direction changing member 9 can change the direction in which the gravel slides and the sliding speed can be reduced. Further, the gravel can be dispersed in the drum by the direction changing member 9 and the space 10.
[0010]
FIG. 4 shows another reference example. FIG. 4 shows a fall energy buffer means of another reference example , in which only a portion corresponding to a portion for guiding the gravel in the gravel meter 2G of FIG. 2 into the drum is described. The fall energy buffering means 7 includes a chute 8 for guiding gravel dispensed from the gravel meter 2G into the drum, and a collision member that is disposed at the lower end of the chute and aggregates out of the lower end of the chute 11. The gravel dispensed from the gravel meter 2G slides down the side wall of the chute 8, and the gravel slipped by the collision member 11 is temporarily received, and the sliding speed is reduced. In the present embodiment, since the collision member 11 is formed in a mountain shape, gravel slides along the mountain shape and can be sufficiently dispersed.
[0011]
【effect】
According to the first aspect of the present invention, since the peak load when the aggregate is charged can be reduced, the power consumption of the variable speed mixer can be reduced. In addition, since the stirring blades are kneaded at a rotational speed closer to the best stirring blade peripheral speed even when the aggregate is charged, high-quality ready-mixed concrete can be manufactured stably. Furthermore, it is possible to increase the agitation blade peripheral speed at the time of adding the aggregate as compared with the conventional case, thereby increasing the aggregate dispersion efficiency immediately after the addition of the aggregate, and to shorten the kneading time.
[0012]
Further, since the aggregate input device has a structure that can temporarily store the aggregate flowing out from the measuring instrument, the aggregate fall distance is halved and the fall energy when the mixer is charged is greatly reduced. In addition, immediately after the aggregate measurement is completed, the aggregate in the measuring instrument can be released to the storage tank, and the next batch can be measured immediately, greatly improving the shipping capacity of the ready-mixed concrete plant. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing load torque, power, and rotation speed of a variable speed mixer.
FIG. 2 is a schematic diagram showing a fall energy buffering means of a first embodiment in a measuring section and a mixer section of a ready-mixed concrete plant.
FIG. 3 is a schematic diagram showing a fall energy buffering means of a second embodiment.
FIG. 4 is a schematic diagram showing a fall energy buffering means of a third embodiment.
FIG. 5 is a schematic diagram showing a measuring section and a mixer section of a conventional ready-mixed concrete plant.
[Explanation of symbols]
1, 1G ··· Storage bin 2, 2G · · Meter 3 · · Variable speed mixer 5 · · Storage tank 6 · Discharge means 7 · Drop energy buffer 8 · · Chute 9 · · Direction change member 11 · · Impact member

Claims (1)

In an aggregate feeding device for introducing aggregate measured by a measuring instrument of a ready-mixed concrete plant equipped with a variable speed mixer capable of increasing or decreasing the number of revolutions of a stirring blade into the drum of the variable speed mixer, the measured aggregate flows out of the measuring instrument. A drop energy buffering means for buffering the falling energy of the aggregate when the storage energy is stored in the storage tank for temporarily storing the aggregate flowing out from the measuring instrument, and the bottom lid of the storage tank is centered on the pin aggregate dosing device you characterized as having a gradual release means for introducing rotating is formed in a structure once stored aggregate ready-mixed concrete plants.

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