JP2000218611A - Sludge water preparation method, sludge water preparation device, and water level sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat sludge water obtained by treating residual ready-mixed concrete and recovering aggregate from the treated water, and to be able to reuse the sludge water well as kneading water for ready-mixed concrete. Provided are a water preparation method and a sludge water preparation device. SOLUTION: Sludge water W from a screw conveyor 3
Is supplied into the storage tank 5 (B). Once this supply is completed, the water level sensor 20 is washed by the shower 31,
Subsequently, the water level of the sludge water W is detected (C). Then
Since the amount of the hydration retarder RE corresponding to the water level is determined,
After a required amount of the hydration retarder RE is supplied to the RE measuring tank 7 via the pump PC2 (D), the hydration retarder RE is injected into the storage tank 5 (E). Subsequently, if the stirring is performed by rotating the stirrer 15 (F), regardless of the water level of the sludge water W, the concentration of the hydration retardant in the sludge water W can be adjusted to a desired value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing sludge water by injecting a hydration retarder into sludge water obtained by treating remaining ready-mixed concrete and recovering aggregate from the treated water, and The present invention relates to a sludge water preparation device and a water level sensor applicable to the sludge water preparation method or the sludge water preparation device.

[0002]

2. Description of the Related Art Conventionally, it has been considered to treat residual ready-mixed concrete using washing water or dilution press water and reuse sludge water obtained after collecting aggregate from the treated water. For example, JP-A-10-180238 discloses that after mixing a hydration retardant with this sludge water, it is repeatedly used as washing water or dilution water, adjusted to a predetermined concentration, and then sent to a ready-mixed concrete production plant. Has been described.

[0003]

However, when the above-mentioned sludge water is repeatedly used as washing water or dilution press water, the amount of the entire sludge water fluctuates during that time. For example, when the amount of water in the entire sludge water is greatly increased, the concentration of the hydration retarder is reduced, so that the chemical effect is reduced or destabilized. For this reason, when this sludge water is reused as kneading water for ready-mixed concrete, quality control of the ready-mixed concrete becomes difficult. In particular, when the washing water or the dilution water is repeatedly used, the use of the sludge water should be avoided. In addition, sludge water that cannot be reused in this way is turned into sludge waste by dehydration treatment or the like. However, this type of sludge waste is difficult to treat because it is strongly alkaline and contains a trace amount of harmful substances.

Therefore, the inventions according to claims 1 to 5 enable the sludge water obtained by treating the remaining ready-mixed concrete and recovering the aggregate from the treated water to be satisfactorily reused as kneading water for the ready-mixed concrete. It has been made for the purpose of providing a sludge water preparation method or a sludge water preparation device that can be used as a method. The invention according to claim 6 has been made to provide a water level sensor that can be favorably applied to the sludge water preparation method or the sludge water preparation device.

[0005]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a sludge obtained by treating residual ready-mixed concrete and collecting aggregate from the treated water. A method of preparing sludge water for preparing water, comprising: a water level detection step of detecting a water level of the sludge water in a tank in which the sludge water is stored; and a water level detection step based on the water level detected in the water level detection step. A hydration retardant injecting step of injecting a hydration retardant in an amount corresponding to
It is characterized by having.

In the present invention configured as described above, first,
In the water level detection step, the water level of the sludge water in the tank in which the sludge water is stored is detected, and in the subsequent hydration retardant injection step, based on the water level detected in the water level detection step, the water level corresponds to the water level. An amount of a hydration retardant is injected into the vessel. For this reason, the concentration of the hydration retardant can be constantly maintained irrespective of the amount of the entire sludge water.

Therefore, if the sludge water is prepared by the method for preparing sludge water according to the present invention, the chemical effect of the hydration retardant can be stably maintained in a desired state, and the sludge water is used as a mixture of ready-mixed concrete. As well as quality control of the ready-mixed concrete becomes easy. Further, as a result, generation of non-reusable sludge water is prevented to prevent generation of sludge waste, and significant effects such as pollution prevention and effective reuse of resources can be obtained. Further, in the present invention, since the concentration of the hydration retardant is always kept constant, the sludge water can be stored as fresh slurry water for a long period of time. For this reason, even if there is a day when the shipment amount of ready-mixed concrete temporarily decreases, the sludge water can be favorably used as kneading water for ready-mixed concrete when the shipment amount increases thereafter. Therefore, when the present invention is used in a commercial plant, the effects of preventing the generation of sludge waste and the effective reuse of resources become even greater.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, when detecting the water level of the sludge water in the water level detecting step, the water level detecting means for detecting the water level is washed. It is characterized by. When the hydration retardant is injected into the sludge water, there is a possibility that foam is generated in the sludge water due to the effect of the hydration retardant. Further, if the foam adheres to the water level detecting means for detecting the water level of the sludge water, accurate water level detection may not be performed in the water level detecting step. Therefore, in the present invention, when detecting the water level of the sludge water in the water level detecting step, the water level detecting means is washed.

Therefore, according to the present invention, the level of the sludge water can be detected more accurately, and the concentration of the hydration retarder in the sludge water can be more accurately maintained at a constant value. Therefore, according to the present invention, in addition to the effect of the first aspect, the chemical effect of the hydration retarder can be maintained more stably, and the sludge water can be re-used as a ready-mixed concrete mixing water. The effect that the quality control of the ready-mixed concrete can be further facilitated while using it is obtained.

[0010] The third aspect of the present invention is the first or second aspect.
In addition to the configuration described above, the water level detecting step and the hydration retardant injecting step are repeatedly performed while supplying the sludge water into the tank. In the present invention, since the water level detection step and the hydration retardant injection step are repeatedly performed while supplying the sludge water in the tank,
The water amount of the entire sludge water can be gradually increased while keeping the concentration of the hydration retarder constant. For this reason, in the present invention, in addition to the effects of the first and second aspects of the present invention, the generation of non-reusable sludge water is more effectively prevented, and the concentration of the hydration retarder in the sludge water is more stably maintained. As a result, there is an effect that the generation of sludge waste can be more effectively prevented and the effective reuse of resources can be promoted more favorably.

According to a fourth aspect of the present invention, there is provided a sludge water preparation apparatus for treating remaining ready-mixed concrete and recovering aggregate from the treated water to prepare sludge water, wherein the sludge water is stored. Water level detecting means for detecting the water level of the sludge water in the tank, and hydration injecting an amount of a hydration retarder corresponding to the water level into the tank based on the water level detected by the water level detecting means. And a delaying agent injection means.

In the present invention thus configured, the water level detecting means detects the level of the sludge water in the tank in which the sludge water is stored, and the hydration retardant injecting means detects the water level by the water level detecting means. Based on the water level, a hydration retarder in an amount corresponding to the water level is injected into the tank. For this reason, in the present invention, the same operation and effect as the first aspect of the invention are produced. That is, the sludge water can be satisfactorily reused as ready-mixed concrete mixing water, and the quality control of the ready-mixed concrete is also facilitated. Further, as a result, the generation of non-reusable sludge water is prevented, the generation of sludge waste is prevented, and enormous effects such as pollution prevention and effective reuse of resources can be produced. Furthermore, sludge water can be stored as fresh slurry water for a long period of time, and when the present invention is used in a commercial plant, the effects of preventing the generation of sludge waste and the effective reuse of resources will be even greater. Become.

According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, when the water level detecting means detects the water level of the sludge water, the water level detecting means further includes a cleaning means for cleaning the water level detecting means. It is characterized by. In the present invention,
When the water level detecting means detects the water level of the sludge water,
Claim 2 wherein the cleaning means cleans the water level detecting means.
The same operations and effects as those of the described invention occur. That is, the water level of the sludge water can be detected more accurately, and the concentration of the hydration retarder in the sludge water can be more accurately maintained at a constant value. Therefore, according to the present invention, in addition to the effect of the invention described in claim 4, the chemical effect of the hydration retardant can be more stably maintained, and the sludge water can be re-used as a ready-mixed concrete mixing water. The effect that the quality control of the ready-mixed concrete can be further facilitated while using the raw concrete is produced.

According to a sixth aspect of the present invention, there is provided a water level sensor for detecting a water level of sludge water obtained by treating remaining ready-mixed concrete and recovering aggregate from the treated water, the level being stored in a tank. In the tank, at least three or more electrodes inserted at different depths, and a water level calculating means for calculating a water level of the sludge water in the tank based on a conduction state between the electrodes, It is characterized by having.

[0015] The present invention thus constructed is provided with at least three or more electrodes inserted into the tank at different depths, respectively, and the water level calculating means uses a tank for the sludge water based on the state of conduction between the electrodes. Calculate the water level in the area. For this reason, the present invention can be favorably used as the water level detecting means according to the second, fourth, or fifth aspect, and is preferably used in performing the water level detecting step according to any one of the first to third aspects. can do.

Further, in the present invention, the water level of the sludge water is calculated based on the conduction state between three or more electrodes inserted at different depths in the tank. When detecting the water level optically, it is affected by the turbidity of the sludge water, and when detecting the water level based on the electric resistance and the dielectric constant between the two electrodes, it is affected by impurities and the like in the sludge water. In the present invention, it is possible to accurately detect the level of the sludge water by eliminating these effects. Therefore, if the water level sensor of the present invention is used as the water level detecting means of the present invention or in performing the water level detecting step of the present invention, the concentration of the hydration retarder in the sludge water can be more accurately maintained at a constant value. . Therefore, in this case, the chemical effect of the hydration retarder can be held more stably, and the sludge water can be more effectively reused as ready-mixed concrete mixing water,
There is an effect that the quality control of the ready-mixed concrete can be further facilitated.

Further, if the water level sensor of the present invention is provided with a cleaning means for cleaning the electrodes when detecting the water level, the water level of the sludge water can be measured in the same manner as described in claim 2 or 5. Detection can be performed even more accurately.

[0018]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram illustrating the configuration and operation of a sludge water preparation device 1 to which the present invention has been applied. Above the storage tank 5 for storing the sludge water W supplied from the screw conveyor 3, an RE measuring tank 7 is disposed as a hydration delaying agent injecting means for measuring and holding the hydration delaying agent RE. .

The screw conveyor 3 is obtained by classifying gravel from a residual ready-mixed concrete discharged from a mixer truck (so-called horse mackerel) (not shown) by an aggregate classifier in advance.
It is a well-known device for collecting sand and fine sand, and the storage tank 5 has sludge water W from which sand is recovered by the screw conveyor 3.
Is supplied. The RE measuring tank 7 has a pump P
A certain concentration of hydration retarder RE from C2 via valve 11
Is supplied, and when the valve 13 provided thereunder is opened, the hydration retarder RE in the RE measuring tank 7 is injected into the storage tank 5.

At the bottom of the storage tank 5, a stirrer 15 as stirring means for stirring the sludge water W in the tank is provided, and at the top of the storage tank 5, a motor 17 for rotating the stirrer 15 is provided. Has been established. Further, a water level sensor 20 as a water level detecting means having eight electrodes 21 to 28 is provided above the storage tank 5, and the electrodes 21 to 21 of the water level sensor 20 are provided.
A shower 31 is provided as cleaning means for cleaning 28. The water level sensor 20 has its eight electrodes 21 to
28 are inserted into the tank at different depths, and an arithmetic unit 29 serving as a water level calculating means determines which electrode is connected to which electrode to detect the water level of the sludge water W. It is.

For example, in the state shown in FIG.
Since the tip of the electrode 22 and the tip of the electrode 22 are disposed below the surface of the sludge water W, only the electrodes 21 and 22 are conductive, and the other electrodes are not conductive. In contrast, FIG.
In the state of (D), since the tips of the electrodes 21, 22, 23 are disposed below the surface of the sludge water W,
A conduction state is established between 2 and 23. The calculating unit 29 calculates the water level of the sludge water W by detecting such a conduction state between the electrodes 21 to 28.

Next, the operation of the sludge water preparation apparatus 1 will be described. First, as shown in FIG.
1, 13 are closed together. At the start of the process, the storage tank 5 may be empty or some sludge water W may be stored as shown in FIG. Next, FIG.
As shown in (B), the sludge water W is supplied from the screw conveyor 3 into the storage tank 5. Once the supply of the sludge water W is completed, the shower 21 cleans the electrodes 21 to 28 of the water level sensor 20,
The water level of the sludge water W is detected based on the conduction states of Nos. To 28. That is, although the water level of the sludge water W is increased by ΔW due to the above-described supply, the water level of the sludge water W after the increase is detected by the water level sensor 20.
FIG. 1C illustrates this water level detection step.

When the water level of the sludge water W is detected as described above, the amount of the hydration retarder RE corresponding to the detected water level is obtained. Therefore, the sludge water preparation device 1 opens the valve 11 as shown in FIG. 1D, and supplies the required amount of the hydration retarder RE to the RE measuring tank 7 via the pump PC2. After supplying the required amount of the hydration retarder RE, the valve 11 is closed and the valve 13 is opened as shown in FIG. 1E, and the hydration retarder RE is injected into the storage tank 5. continue,
As shown in FIG. 1 (F), the stirrer 15 is
To uniformly disperse the injected hydration retarder RE in the sludge water W. Thereby, regardless of the water level of the sludge water W in the storage tank 5, the concentration of the hydration retarder in the sludge water W can be adjusted to a desired value.

When the sludge water W is supplied from the screw conveyor 3 during this time, the electrodes 21 to 28 of the water level sensor 20 are washed by the shower 31, and then the process shifts again to the water level detecting step of FIG. Then, the hydration retarder RE corresponding to the increased water level of the sludge water W is stored in the storage tank 5 by the hydration retardant injection step described above with reference to FIGS. 1 (D) and 1 (E). Inject into At this time, the injection amount of the hydration retarder RE is calculated by subtracting the amount of the hydration retarder RE already injected so far. As a result, even if the sludge water W is supplied one after another from the screw conveyor 3, the concentration of the hydration retarder in the sludge water W can always be kept constant. Then, the sludge water W thus prepared is sent to a ready-mixed concrete manufacturing plant, and is reused as ready-mixed concrete mixing water.
The operation of the pump PC2 and the valves 11, 13 is as follows.
It may be performed automatically by control means such as a computer, or may be performed by an operator via an operation panel or the like.

As described above, the sludge water preparation apparatus 1 of the present embodiment can always keep the concentration of the hydration retarder RE constant irrespective of the amount of the entire sludge water W. Further, in the sludge water preparation device 1, the water level sensor 20
Since the electrodes 21 to 28 of the water level sensor 20 are washed by the shower 31 when detecting the water level of the sludge water W via the, the water level of the sludge water W can be detected more accurately as follows. . That is, when the sludge water W obtained by the treatment of the residual concrete flows into the storage tank 5 from the screw conveyor 3, a large amount of bubbles due to the admixture contained therein may be generated. If water adheres to the electrodes 21 to 28, accurate water level detection may not be possible. On the other hand, in the present embodiment, the electrodes 21 to 28 are washed in detecting the water level, so that the water level can be detected very accurately, and the hydration delay of the sludge water W can be extended. The agent concentration can be more accurately maintained at a constant value.

Therefore, the chemical effect of the hydration retarder RE in the sludge water W stored in the storage tank 5 can be maintained very stably in a desired state, and the sludge water W
Can be reused as a ready-mixed concrete mixing water very well, and the quality control of the ready-mixed concrete becomes very easy. Further, as a result, the generation of non-reusable sludge water can be extremely effectively prevented, the generation of sludge waste can be prevented, and enormous effects such as pollution prevention and effective reuse of resources can be obtained.

Further, in the sludge water preparation apparatus 1, since the concentration of the hydration retarder RE is always kept constant, the sludge water W stored in the storage tank 5 can be stored as fresh slurry water for a long time. Can be. For this reason, even if there is a day when the shipment volume of ready-mixed concrete temporarily decreases, the sludge water W
Can be satisfactorily used as kneading water for ready-mixed concrete. Therefore, when the sludge water preparation apparatus 1 is used in a commercial plant, the effects of preventing the generation of sludge waste and the effective reuse of resources become even greater.

Further, in the present embodiment, the water level detecting step shown in FIG. 1C and the hydration retardant injecting step shown in FIGS. Hydration retarder RE
While maintaining the concentration of the sludge constant, it is possible to gradually increase the water amount of the entire sludge water W. Therefore, in the present embodiment, the generation of non-reusable sludge water can be prevented more favorably and the concentration of the hydration retarder in the sludge water W can be more stably maintained. And the effective reuse of resources can be further promoted.

It should be noted that the present invention is not limited to the above embodiment at all, and it goes without saying that the present invention can be implemented in various forms as long as it belongs to the technical scope of the present invention. For example, after temporarily shifting to the step of FIG. 1 (F), all the sludge water W in the storage tank 5 may be sent to the ready-mixed concrete production plant, and the processing may be started again from the step of FIG. 1 (A). . In this case, the process shown in FIG.
There is no loop processing to shift to the process, and the need to clean the water level sensor 20 in the process of FIG.

The water level detecting means for detecting the water level of the sludge water W in the storage tank 5 includes, in addition to the water level sensor 20,
Various configurations are possible. For example, an ultrasonic sensor that generates ultrasonic waves from above the storage tank 5 downward may be used, or a sensor that optically detects the water level by a combination of a light emitting diode and a phototransistor may be used, Two flat electrodes may be arranged in parallel from the upper end to the lower end of the storage tank 5, and the water level may be detected based on the electric resistance or the dielectric constant between the two.

However, when the water level is optically detected, the water level is affected by the turbidity of the sludge water W. When the water level is detected based on the electric resistance and the dielectric constant between the two electrodes, the water level in the sludge water W is not detected. Of impurities. On the other hand, in the water level sensor 20 of the sludge water preparation device 1, the water level of the sludge water W is determined based on the conduction state between the eight electrodes 21 to 28 inserted at different depths in the storage tank 5. Since the calculation is performed, these effects can be eliminated, and the water level of the sludge water W can be accurately detected. Therefore, in the present embodiment, the concentration of the hydration retarder in the sludge water W can be more accurately maintained at a constant value. Therefore, the hydration retarder RE
Can be maintained more stably, and the sludge water W can be reused as a ready-mixed concrete mixing water, and the quality control of the ready-mixed concrete can be further facilitated. Moreover, the water level sensor 20 using the electrodes 21 to 28 having different lengths has a simple structure and is inexpensive as compared with an ultrasonic sensor or the like. Therefore, in the present embodiment, the manufacturing cost of the sludge water preparation device 1 can be favorably reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the configuration and operation of a sludge water preparation device to which the present invention has been applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sludge water preparation apparatus 3 ... Screw conveyor 5 ... Storage tank 7 ... RE measuring tank 15 ... Stirrer 20 ... Water level sensor 21, 22, 23, 24, 25, 26, 27, 28 ... Electrode 29 ... Calculation part 31 ... Shower RE: Hydration retardant W:
Sludge water

Claims (6)

[Claims] 1. A method for preparing sludge water by treating residual ready-mixed concrete and recovering aggregate from the treated water, wherein the sludge in a tank in which the sludge water is stored is provided. A water level detection step of detecting a water level of water, and a hydration retardant injecting step of injecting a hydration retarder in an amount corresponding to the water level into the tank based on the water level detected in the water level detection step, A method for preparing sludge water, comprising: 2. The method for preparing sludge water according to claim 1, wherein in detecting the water level of the sludge water in the water level detecting step, a water level detecting means for detecting the water level is washed. 3. The method for preparing sludge water according to claim 1, wherein the water level detecting step and the hydration retardant injecting step are repeatedly performed while supplying the sludge water into the tank. . 4. A sludge water preparation apparatus for treating remaining ready-mixed concrete and recovering aggregate from the treated water to prepare sludge water, wherein the sludge in a tank in which the sludge water is stored. Water level detection means for detecting the water level of water, based on the water level detected by the water level detection means, hydration retardant injection means for injecting a hydration retardant in an amount corresponding to the water level into the tank, An apparatus for preparing sludge water, comprising: 5. The apparatus for preparing sludge water according to claim 4, further comprising a washing means for washing the water level detecting means when the water level detecting means detects the water level of the sludge water. 6. A water level sensor for detecting a water level stored in a tank of sludge water obtained by treating remaining ready-mixed concrete and collecting aggregate from the treated water, wherein: At least 3 each inserted at a different depth
A water level sensor, comprising: at least one electrode; and a water level calculation means for calculating a water level of the sludge water in the tank based on a conduction state between the electrodes.