JPH05208413A - Method of stabilizing moisture in sand - Google Patents

Abstract

PURPOSE:To enable the moisture stabilization of sand to be effected readily by performing the draining of sand placed in a primary storage tank through a draining structure of the primary storage tank, and after measurement, performing secondary draining in placing only a sand of a predetermined surface moisture rate or less into a secondary storage tank. CONSTITUTION:In the case of placing sand into a primary hopper 11 by a truck or the like, a shuttle conveyer 16 is turned to the side of a primary storage tank 1 for supplying the sand transported from the primary hopper 11 via an inclined conveyer 15. The sand within the primary storage tank 1 is subjected to draining after left standing for a predetermined period (about three days). After that, the conveyer 7 is operated for placing the sand passed through a discharge gate 3 into a secondary hopper 8, wherein the surface moisture rate of the sand is measured by a moisture meter 9. In the case where the measured value is more than a predetermined value, the shuttle conveyer 16 is turned to the side of the primary storage tank for conducting draining again within the primary storage tank 1, whereas in the case where it is less than the predetermined value, the shuttle is turned to the side of a secondary storage tank 2 for conducting secondary draining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stabilizing the water content of sand.

[0002]

2. Description of the Related Art When producing ready-mixed concrete, it is particularly important to control the surface water ratio of sand, which directly affects the water / cement ratio. In conventional batcher plants, the sand is left in a storage tank for several days. We use after draining.

FIG. 2 is a side view showing an outline of an example of a method for stabilizing water content of sand in a conventional batcher plant. It has a capacity to store several days' worth of sand as a raw material, and gravel a is spread to a predetermined thickness as shown in FIG.
2 storage tanks e and f having a draining structure c and a discharge gate d at the bottom are provided, and a conveyor h extending in the backward facility direction (not shown) is provided below the storage tanks e and f. ing.

While the sand g, which has been previously put into one of the storage tanks e and drained, is cut out from the discharge gate d onto the conveyor h and fed to the rear equipment, it is carried in by a truck or the like and is not shown in a stockyard. The sand temporarily stocked in is stored in the other storage tank f.

The water adhering to the surface of the sand i stored in the storage tank f flows downward in the storage tank f due to the action of gravity and gathers in the draining structure c to drain the water. Is discharged to the outside, and as a result, the water content of the sand i is cut off and the surface water ratio (weight of water adhering to the surface of the sand grains / weight of sand + weight of water) decreases.

However, this surface water ratio differs depending on the position in the height direction in the storage tanks e and f, and as shown in FIG. 3, a large amount of water tends to remain in the sand below the storage tanks.

After all the sand g in one of the storage tanks e has been discharged, the cut-out of the sand i in the other storage tank f, in which the water content has been removed and the surface water content has been lowered as described above, is discharged. Although it is performed through the gate d, at that time, a part of the sand i that is first cut out in the lower part of the storage tank f has a relatively large surface water rate as described above, and therefore is put into a separate tank (not shown), The remaining sand i having a relatively low surface water ratio is sent to the rear equipment by the conveyor h. At this time, the surface water content of the sand is controlled by an instrument such as an automatic moisture meter (not shown) provided on the conveyor h.

As described above, the sand i in the storage tank f is cut out, and at the same time, the sand stocked in the stock yard is put into the storage tank e which has become an empty tank, like the sand i in the storage tank f. It is stored in and the moisture is removed to reduce the surface water rate.

By alternately cutting out the sands g and i stored in the two storage tanks e and f capable of lowering the surface water ratio as described above, the sand required by the rear equipment can be sequentially fed. is doing.

[0010]

However, in the above-described method for stabilizing the moisture content of sand, the moisture content of the sand when it is carried into the stockyard, the stock state of the sand on the stockyard, and the storage in the storage tank. The surface water rate of the sands g and i fluctuates greatly depending on the elapsed time.

In addition, since the accuracy of the conventional automatic moisture meter is low and it is difficult to obtain a good automation equipment, the surface water rate of the sand g, i supplied to the rear equipment is not always stable. Therefore, the water content is actually adjusted based on the experience and intuition of the operator at the site, and there is a problem that it is difficult to always maintain the quality of green concrete in a good state.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for stabilizing the water content of sand which can stabilize the surface water content of the sand at a predetermined surface water content or less.

[0013]

According to the present invention, sand is put into a primary storage tank having a draining structure to remove water adhering to the surface of the sand to reduce the surface water ratio, and then the primary storage tank. Measure the surface water rate of the sand cut out from, sand having a surface water rate of a predetermined surface water rate or more is refluxed to the primary storage tank,
Sand having a predetermined surface water ratio or less is put into a secondary storage tank having a drainage structure to further reduce the surface water ratio.

[0014]

Therefore, according to the present invention, the primary drainage of the sand put into the primary storage tank is performed by the drainage structure of the primary storage tank, and only the sand having a predetermined surface water ratio or less after the measurement is put in the secondary storage tank. By using the drainage structure of the storage tank to perform secondary drainage of the sand put into the secondary storage tank, the surface water rate of the sand can be sufficiently reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing the outline of an example of equipment for carrying out the method for stabilizing the moisture content of sand according to the present invention. A primary storage tank 1 and a secondary storage tank 2 each having a horizontal bottom surface and having a capacity capable of storing sand for a required number of days (for example, about 3 days) as a product raw material are provided in series, and each storage tank is provided. Discharge gates 3 are arranged at predetermined intervals in the bottom direction of the storage tanks 1 and 2 in the storage tank parallel direction, and a draining structure 4 is provided around the discharge gates 3. The drainage structure 4 is the discharge gate 3 of each storage tank 1, 2.
It is formed by the gravel 5 spread to a predetermined thickness on the bottom surface excluding the portion where the is arranged and the drain hole 6 arranged at a predetermined interval.

A conveyor 7 extending to the side opposite to the secondary storage tank 2 is provided below the discharge gate 3 of the primary storage tank 1, and a secondary hopper 8 is provided below the tip of the conveyor 7 to provide the secondary hopper 8. A water content meter 9 is attached to the outside of the water content, and the water content of the sand in the secondary hopper 8 detected by the water content meter 9 is provided with a control unit 10 for outputting a control signal for controlling the operation of a conveyor, which will be described later. Connect to a total of 9.

Further, a primary hopper 11 is provided at a predetermined position near the primary storage tank 1 for receiving sand carried in by a truck, and an inclination extending from below the discharge gate 12 of the secondary hopper 8 to above the primary hopper 11. A conveyor 13 is provided, and an inclined conveyor 15 extending from below the discharge gate 14 of the primary hopper 11 to above the primary storage tank 1 is provided. Below the tip of the inclined conveyor 15, the primary storage tank 1 and the secondary storage tank 2 are provided. A shuttle conveyor 16 extending horizontally across the center is provided above both storage tanks 1, 2.

Further, a receiving operation box 17 capable of outputting an operation command signal to send sand to the primary storage tank 1 or the secondary storage tank 2 based on the signal transmitted from the control unit 10 is provided, and the receiving hopper 8 is provided. Secondary hopper 1 via inclined conveyor 13
To send to the shuttle conveyor 16 a command signal as to whether the sand to be fed to the first storage tank 1 and then to the shuttle conveyor 16 via the inclined conveyor 15 is fed to the primary storage tank 1 or the secondary storage tank 2. To do.

Further, in order to feed the sand in the secondary storage tank 2 from the secondary storage tank 2 to the rear equipment (not shown), a conveyor extending from below the discharge gate 3 of the secondary storage tank 2 toward the rear equipment. 18 is provided.

Next, the operation will be described. When sand is thrown into the primary hopper 11 by a truck or the like, the shuttle conveyor 16 on the primary storage tank 1 and the secondary storage tank 2 is rotated in the direction of the primary storage tank 1 by the operation command signal output from the receiving operation box 17. Then, the inclined conveyor 15 extending from below the discharge gate 14 of the primary hopper 11 to above the primary storage tank 1 is operated, and the discharge gate 14 of the primary hopper 11 is opened. Thus, the sand put into the primary hopper 11 passes through the opened discharge gate 14 and the inclined conveyor 15
It is discharged to the upper side and supplied to the primary storage tank 1 by the inclined conveyor 15 and the shuttle conveyor 16.

The sand stocked in the primary storage tank 1 is left as it is for a required period (for example, about 3 days). In the meantime, the moisture adhering to the surface of the sand flows downward in the primary storage tank 1 due to the action of gravity, collects in the draining structure portion 4 and is discharged to the outside from the drainage hole 6.

After leaving for a required time, the conveyor 7 extending from below the discharge gate 3 of the primary storage tank 1 to above the secondary hopper 8 is operated, and then the discharge gate 3 is opened. Then, the conveyor 7 is provided through the drainage gate 3 which opens the drained sand.
It is discharged to the upper side and charged into the secondary hopper 8 by the conveyor 7.

When sand is thrown into the secondary hopper 8, the moisture meter 9 provided outside the secondary hopper 8 operates to activate the secondary hopper 8.
The surface water rate of the sand inside is measured, and a detection value signal is transmitted to the control unit 10. The control unit 10 that has received the detection signal
If the measured surface water ratio of sand is higher than a predetermined surface water ratio (for example, 6%), the shuttle conveyor 16 provided on the storage tanks 1 and 2 with respect to the receiving operation box 17 is the primary storage tank. A command signal is transmitted to rotate to the 1 side, and when the surface water ratio of the sand is low, the shuttle conveyor 16 rotates to the secondary storage tank 2 side with respect to the receiving operation box 17. Send a command signal.

The inclined conveyor 1 extending from below the discharge gate 12 of the secondary hopper 8 to above the primary hopper 11 in response to the operation command signal output from the receiving operation box 17 that has received the command signal.
3, the inclined conveyor 15 extending from below the discharge gate 14 of the primary hopper 11 to above the primary storage tank 1, and the shuttle conveyor 16 is operated, and the discharge gate 12 of the secondary hopper 8 and the discharge gate 14 of the primary hopper 11 are operated. Opens. Thus, the sand thrown into the secondary hopper 8 is sorted according to the surface water ratio, and the inclined conveyor 1
It is fed to the primary storage tank 1 or the secondary storage tank 2 via the 3 and the inclined conveyor 15 and the shuttle conveyor 16.

The sand having a high surface water ratio sent to the primary storage tank 1 is again subjected to the draining action in the primary storage tank 1. Also,
The sand having a low surface water ratio sent to the secondary storage tank 2 is discharged onto the conveyor 18 through the discharge gate 3 of the secondary storage tank 2 as required by the rear equipment, and the conveyor 18 causes the rear equipment to flow backward. Sent to.

According to the above, the moisture meter 9 is provided in the secondary hopper 8 provided on the downstream side of the primary storage tank 1, and the surface water rate of the sand fed from the primary storage tank 1 to the secondary hopper 8 is calculated as described above. Moisture meter 9
The sand is classified according to the level of the surface water ratio of the sand measured, and the sand having a high surface water ratio is returned to the primary storage tank 1 in order to drain the sand again, and the sand is cooled to a predetermined level. Only sand with a surface water ratio or less is stocked in the secondary storage tank 2 and formed so that it can be sent to the rear equipment as needed, so that sand with a stable surface water ratio or less is always supplied to the rear equipment. be able to.

It should be noted that the present invention is not limited to the above-mentioned embodiments, for example, a bucket elevator may be used instead of each inclined conveyor, and a secondary hopper may not necessarily be provided. Of course, various changes can be made without departing from the scope of the present invention.

[0029]

According to the method for stabilizing water content of sand of the present invention,
The surface water rate of the sand drained by the primary storage tank is measured, and the sand is classified according to the level of the measured surface water rate of the sand, and the sand having a higher surface water rate than the predetermined surface water rate is the sand. It was refluxed to the primary storage tank to drain water again, and it was formed so that only sand with a predetermined surface water ratio or less could be stocked in the secondary storage tank, so a stable surface with a predetermined surface water ratio or less It is possible to obtain an excellent effect that sand having a water rate can always be obtained.

[Brief description of drawings]

FIG. 1 is a side view schematically showing an example of equipment for carrying out the method for stabilizing water content of sand of the present invention.

FIG. 2 is a side view showing an outline of an example of a conventional method for stabilizing water content of sand.

FIG. 3 is a distribution diagram for each height position of the surface water ratio of sand related to FIG. 2;

[Explanation of symbols]

 1 Primary storage tank 2 Secondary storage tank 4 Draining structure

Front Page Continuation (72) Inventor Koichi Yokoi 3174 Showa-cho, Kanazawa-ku, Yokohama, Kanagawa Ishikawajima Construction Machinery Co., Ltd. Yokohama factory

Claims (1)

[Claims] 1. The surface water ratio of the sand cut out from the primary storage tank after the sand is put into a primary storage tank having a drainage structure to remove water adhering to the surface of the sand to reduce the surface water ratio. The sand having a surface water ratio of a predetermined surface water ratio or more is refluxed to the primary storage tank, and the sand having a predetermined surface water ratio or less is put into a secondary storage tank having a draining structure to obtain a surface water ratio. A method for stabilizing the water content of sand, which further reduces the water content.