JPS5811536Y2 - cement mixing equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cement mixing device applied to a soft ground improvement device, etc.

The conventional cement mixing system uses a batch metering and batch mixing method, and is composed of a measuring bin batch mixer.

Measuring and mixing takes as much as 3 to 6 minutes, so if you try to increase the mixing capacity per unit time, it is inevitable that equipment such as measuring bottles and mixers will become larger.

In addition, when mixing only cement and water, it is not possible to expect the mixing effect due to the mixing of sand and shari, etc., as in the case of mixing mortar or concrete. Efforts such as mixing are required, which inevitably increases the mixing time and increases the size of the device.

Moreover, in a cement mixer, cleaning after use is essential due to the inherent property of cement that it solidifies if left as is, but cleaning a conventional batch mixer is not easy due to its shape.

In addition, in conventional continuous mixing mixers, the mixing ratio must be adjusted manually, and the operation is manual operation, which is suitable for short-term operation, and is suitable for large-capacity and long-term operation such as soft ground improvement equipment. It was not suitable for applications that required continuous operation.

Therefore, the purpose of this invention is to eliminate the above-mentioned drawbacks, and provide a cement mixing device that is compact in size, easy to clean, and can be operated automatically. , and the mixture ratio control and operation are automated.

Embodiments of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a program diagram showing the overall configuration of the cementing system of a soft ground improvement device to which the present invention is applied, and Fig. FIG. 3 is a block diagram showing the configuration of an automatically operated cement mixing system according to an embodiment, and is a side sectional view showing the structure of a jet mixer.

4 to 11 show another embodiment of the present invention.

In Figure 1, 1 is a mixer that mixes cement and water, 2 is an agitator tank that temporarily stores the mixed cement slurry, 3 is an agitator mixer, and 4 is a mixer that mixes cement slurry into the soil to be improved. a cement injection pump for injecting into the cement tank;
6 is a water tank, and 7 is a storage tank for stabilizers and other additives.

Cement, water and additives are mixed in appropriate proportions in a mixer 1, and are injected into the soil by a cement injection pump 4 through a nozzle 9.

At the same time, the stirring blade 8 rotates to stir and mix the soil and cement.
After that, the cement hardens, increasing the strength of the ground.

In FIG. 3, the jet mixer 1 includes a hopper portion 1b for receiving cement, a water jet nozzle 1a, and a mixing chamber 1C.

When the water is ejected from the jet nozzle 1a, it instantly mixes with the cement falling from the hopper 1b and is discharged.

In Fig. 2, 1 is a jet mixer, 2 is an agitator tank, 3 is an agitator mixer, 4 is a cement injection/pump, 5 is a cement tank, 5a is a load cell that detects the cement level in the cement tank, 5b
, 5C is a control unit for controlling a control valve 5d that adjusts the amount of cement supplied to the cement tank 5 depending on the cement level.

6 is a water tank, and 6a is a float valve for adjusting the water level of the water tank 6.

7 is an additive tank, 10 is a rotary feeder for supplying a fixed amount of cement from the cement tank to the mixer 1, 10a is its drive motor, 11 is a mixing pump that supplies water to the mixer, 11a1 is an agitator tank 2 11b is a flow rate adjustment valve that adjusts the amount of water to the mixer; 12 is an additive injection pump; 12a is a shutoff valve that opens and closes depending on the level of the liquid level in the agitator tank 2; 12b is a flow meter, 12C is a flow control valve,
Reference numeral 13 indicates a pump that supplies slurry to the density meter 14 for cement slurry.

14 a is the rotation speed of the rotary feeder using the density meter 1.
This is a cement supply amount controller for controlling according to the signal from No. 4.

Reference numeral 15 indicates a mixer operation control device that starts and stops the mixer according to the level of the liquid in the agitator tank 2, and 16 and 17 indicate liquid level gauges.

Next, to explain its operation, first, when the start switch is turned on (not shown), the cement supply amount controller 14
A start-up sequence built into H operates to rotate the rotary feeder 10 at a predetermined number of rotations (adjustable).

At the same time, the mixing pump 11. Additive injection pump 1
2. Start the density meter pump 13 and close the valves 11a and 1.
Let 2a be open.

The cement slurry mixed in the mixer 1 enters the agitator tank 2 and reaches the density meter 14.

The startup sequence is switched to a steady operation sequence for a limited time.

At this time, for the first time, the value from the density meter 14 is fed back to the rotation speed control of the rotary feeder 10.

That is, in the cement supply amount controller 14H, the target value and
The value from the density meter is compared, and the rotation speed of the rotary feeder 10 is controlled to increase or decrease depending on the deviation.

When the liquid level of the cement slurry reaches the liquid level gauge 16, the mixer operation control device 15 sends a signal to the cement supply amount controller 1.
4a A stop signal is output to the mixing pump 11, additive injection pump 12, shaft off valve lla, and 12a,
Mixing will stop automatically.

When the cement injection pump 4 is activated and starts consuming cement slurry, the liquid level in the agitator tank 2 begins to fall.

When the liquid level reaches the liquid level gauge 17, the operation control device 15 starts up the mixer 1 again, but this time, the density meter 14 shows
Since the cement slurry to be measured is in contact with the cement slurry, the startup sequence is not activated and the steady operation sequence is immediately entered to perform mixing. Therefore, in order to reduce this as much as possible, the level of the cement tank 5 is controlled.

That is, the cement tank 5 is suspended via a load cell 5a, which detects the weight of cement and keeps the level constant by adjusting the opening degree of the control valve 5d using control valves 5b and 5C.

Another element of disturbance in the specific gravity control system is the fluctuation in the amount of water sent to the mixer 1 by the mixing pump 11, but the water surface of the water tank 6 is kept in a fixed position by using means such as the float valve 6a, and the flow rate fluctuation is prevented. Reduce.

Further, dead time is long when the capacity of the agitator tank 2 is large or when a type of density meter using a radioactive isotope is used.

Since this may involve problems such as a large time constant, a highly accurate mixing system can be obtained by incorporating a sampling control element into the controller 14a.

FIG. 4 shows a second embodiment.

Here, the numbers 1 to 17 are the same as those shown in the first embodiment.

18 is a screw feeder, and 18a is a variable speed motor that drives the screw feeder.

19 is a conveyor scale, driven by a constant speed motor 19a, a measuring device 19b measures the amount of cement on the conveyor, a quantitative supply controller 19C compares it with a target value,
Screw feeder motor 18 to eliminate deviation
Control the rotation speed of a.

A flow meter 11C is attached to the discharge side of the mixing pump 11 to constantly supply a fixed amount of water to the mixer.

FIG. 5 shows a third embodiment.

In this case, instead of the belt scale of the second embodiment, a screw conveyor scale 21 is used for quantitatively supplying cement.

The screw conveyor is suspended by a load cell 21C to measure the amount of cement in the screw conveyor.

The quantitative feed controller 21d compares it with the target value, and controls the rotation speed of the variable speed motor 21e of the rotary feeder 21b so as to make the deviation zero.

The screw feeder 21 is driven by a constant speed motor 21a.

Other parts are similar to those shown in the first and second embodiments.

FIG. 6 shows the fourth embodiment, in which feedback control of the screw conveyor scale is not performed and the load cell 2 is
1C and the speed of the screw conveyor by the pulse generator 21f, the calculation unit 22 calculates the cement supply amount per unit time,
The water supply control valve 24 uses the output as a set value.
By inputting the water to the control device 23, proportional control of the amount of water supplied to the cement supply is performed.

The drive motor 21e of the rotary feeder 21b is a constant speed motor, and is controlled only to start and stop according to instructions from the operation control device 15.

Other parts are similar to those shown in the first and second embodiments.

FIG. 7 shows a fifth embodiment, in which the drive motor 10b of the rotary feeder 10 is a constant speed motor, feeds back the value of the density meter 14, and controls the water supply control valve and additive injection control valve 12d. A supply amount controller 25 controls the amount of water supplied to keep the density constant.

Other parts are similar to those shown in the first embodiment.

FIG. 8 shows a sixth embodiment, in which the agitator tank that is located between the mixer and the cement injection pump and serves as a buffer tank is omitted, and a small-capacity mixing tub 26 is provided instead. It is something that

The cement supply section is by a conveyor scale with a metering device similar to that shown in the second or third embodiment.

However, in order to control the level of the mixing tab 26, the cement supply amount setting value of the quantitative supply controller 21d is
It is changed by the output from the level meter 29.

That is, the value from the flow meter 28 attached to the suction line of the cement injection pump 4 is input to the level controller 29, where a control signal is sent to supply cement and water in accordance with the cement slurry flow rate. , a quantitative supply controller 21d, a water supply control valve 11d, and an additive injection pump rotation speed controller 12e.

Further, a level detector 26a and a control signal generator 27 are provided in the mixing tub 26, and cascade control is applied to the level controller 29 in order to keep the liquid level in the mixing tub constant.

FIG. 10 shows a seventh embodiment.

In FIG. 9, a portion of the mixer is shown in a side sectional view.

This mixer is known as a recirculating jet mixer.

In Figures 9 and 10, 30 is a recirculating pump, 31 is a mixing tab, 32 is a mixer 33 is a gate control motor for adjusting the amount of cement supplied, and 34 is an agitator, which opens and closes the cement according to the liquid level in the tank. In the supply shutoff valve, 37 is the overflow pipe of the mixing tub, and 38 is the discharge pipe from the mixer.

This type of mixer is basically the same as the hopper jet type mixer, but the cement supply amount can be adjusted by 331.
In order to improve the mixing precision, the mixed slurry is returned to the mixer 32 by the circulating pump 30 and added to the water supplied from the mixing pump 11 to be mixed again. It is in.

The slurry in the mixing tub is guided by a pump 13 to a densitometer (for example, a U-shaped densitometer) 14, and its density is measured.

This value is manually inputted to the cement supply amount controller 35, where it is compared with the set value, and a servo signal is generated to make the deviation zero, and the cement supply amount adjustment gate control motor 3
Control 3.

15 is an operation control device similar to the other embodiments described above, and depending on the level of the liquid in the agitator tank 2, a water shutoff valve 11a, an additive injection shutoff valve 12a, and a cement supply shutoff valve are activated. The slurry supply shutoff valve 36 opens and closes the diagonal slurry supply shutoff valve 36, respectively, and also has the role of starting and stopping the mixing pump 11 and the injection pump 12.

FIG. 11 shows an eighth embodiment similar to FIG. 10 in which a recirculating mixer is used and the agitator tank is omitted.

Reference numeral 41 denotes a flow meter, which integrates and calculates the amount of slurry transferred by the cement injection pump 4 using the level controller 40, and controls a water control valve 11a and an injection pump rotation speed controller 12e in order to provide the mixer with the corresponding amount of water. At the same time, a differential element control signal is sent to the cement supply amount controller to speed up the response operation of the density adjustment control system to water amount fluctuations.

In the above explanation, only the basic operation of the control system has been shown, but in reality, feedback is incorporated into each system to improve controllability.

In this way, according to this embodiment, by incorporating a jet mixer into a cement mixing device for supplying cement slurry to soft ground improvement equipment, etc., it is possible to make the entire device compact, lightweight, and compact. This has the effect that the mixing of cement and water, which is difficult to mix, can be done quickly, and a large amount of cement slurry can be continuously supplied in a short period of time, and washing with water can be easily performed.

It also detects either the amount of cement supplied to the cement mixing device or the density of the cement slurry mixed by the jet mixer, and based on this, automatically feedback controls the amount of supplied cement, water, and additives, that is, the mixing ratio. By incorporating a control device that does this, it is possible to automatically and continuously supply cement slurry with a constant concentration with high mixing accuracy.

Furthermore, by incorporating a control device that automatically controls the operation of the cement, water, and additive supply means and the jet mixer, depending on the amount of cement slurry in the container that receives the cement slurry mixed with the jet mixer.
In response to the consumption of a large amount of cement slurry that is continuously sent into soft ground, and in response to changes in the consumption rate and amount, the necessary amount of cement slurry is always maintained without excess or deficiency.
It has the effect of supplying

As described above, according to the present invention, each supply means includes a cement tank, a water tank, and an additive tank, a jet type mixer that mixes the cement, water, and additives supplied from each supply means, and a container for storing the slurry mixed by the mixer; a first control means for automatically controlling the mixing ratio according to the cement supply amount or the slurry density; and a first control means for automatically controlling the mixing ratio according to the amount of the slurry in the container; By being equipped with a second control means that automatically controls, it is possible to automatically obtain cement slurry with high mixing accuracy from startup to operation, and to realize a compact and lightweight cement mixing system. It is industrially useful.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the overall configuration of a cementing system in which the present invention is applied to a soft ground improvement device, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is used in the embodiment. A side sectional view of the jet mixer, FIGS. 4 to 8 are block diagrams showing the second to sixth embodiments, and FIGS. 9 and 10 are the seventh embodiment,
FIG. 9 is a side sectional view of the jet mixer, FIG. 10 is a block diagram, and FIG. 11 is a block diagram showing the eighth embodiment. 1...Jet type mixer, 2...
・Agitator tank, 4... Cement injection pump, 5... Cement tank, 6...
Water tank, 7...Additive tank, 14a...
...Cement supply amount controller, 15...Mixer operation control device.

Claims (1)

[Scope of utility model registration request] Each supply means consisting of a cement tank, a water tank, and an additive tank is connected to a jet type mixer that mixes the cement, water, and additives supplied from each supply means, and the slurry mixed by the mixer is stored. a container; a first control means for automatically controlling the mixing ratio according to the cement supply amount or slurry density; and a second control means for automatically controlling the operation of the respective supply means and the mixer according to the slurry amount in the container. A cement mixing device characterized by comprising: