JP3872678B2 - Flocculant automatic injection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic flocculant injection device that injects an optimal amount of flocculant into a liquid mixed with solid foreign matters such as turbid water and removes the solid foreign matters from the liquid.
[0002]
[Prior art]
Conventionally, when turbid water generated by excavation at a construction site is discharged to a river or the like, it is necessary to separate muddy components of turbid water and discharge only the remaining fresh water from the viewpoint of pollution prevention and environmental protection. In order to remove the mud component of the turbid water, a flocculant is added to the turbid water so that the mud component can be easily separated, but an appropriate amount of the flocculant is injected from the experience of the operator.
[0003]
[Problems to be solved by the invention]
Therefore, it is difficult to inject an optimal amount of the flocculant according to the turbidity of the turbid water, and the flocculant is often excessively injected, and the flocculant is mixed with fresh water and discharged unnecessarily. Has occurred.
[0004]
The present invention aims to eliminate the above-mentioned drawbacks, and calculates the injection amount of the coagulant optimum for the turbidity of the liquid mixed with solid foreign matters such as turbid water and can inject this coagulant automatic injection device Is to provide.
[0005]
[Means for Solving the Problems]
A bent pipe is arranged between the inflow pipe and the outflow pipe that are arranged in a straight line, and the liquid mixed with solid foreign substances from the inflow pipe passes through the bent pipe and is discharged from the outflow pipe. While calculating the density of the liquid mixed with solid foreign substances from the natural frequency, and calculating the turbidity of the liquid from this density and the true specific gravity of the solid foreign substances calculated in advance,
An optimum flocculant injection amount corresponding to the turbidity of the liquid is calculated from the calculated turbidity of the liquid and the optimum flocculant injection amount for the turbidity stored in advance.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, based on the drawings, embodiments of the present invention will be described with respect to turbid water as an example of a liquid mixed with solid foreign matters. In FIGS. 1 to 3, 1 is a coagulant automatic injection device attached to a muddy water treatment device (not shown) for discharging only clean water from muddy water generated by excavation at a construction site into a river. The raw water tank 2 provided with the filter part 2a for removing the above solid foreign substances, the mass flow meter 4 attached to the raw water tank 2 together with the circulation pump 3, and the turbid water sent from the raw water tank 2 by the raw water pump 5 are temporarily stored. It consists of a storage tank 6, a mixer 7, and a coagulant storage tank 8 in which the coagulant sent out by the coagulant pump 8a is stored.
[0007]
The raw water tank 2 has a level meter 2b for detecting the water level. When the muddy water reaches the lowest water level or the highest water level, each detection signal is turned on and output to the arithmetic unit 9 described later. ing. The raw water tank 2 is connected to a supply pump (not shown) for supplying muddy water, and an operator operates the supply pump according to the amount of muddy water in the raw water tank 2 to generate an appropriate amount of muddy water. It is configured to be supplied to the water tank 2.
[0008]
The mass flow meter 4 is composed of an inflow pipe 4a arranged in a straight line, an outflow pipe 4b, and a bent pipe 4c arranged in a horizontal direction between these pipes, and solid foreign matter is mixed in from the inflow pipe 4a. The bent pipe 4c is configured to vibrate when the turbid water passes through the bent pipe 4c and is discharged from the outflow pipe 4b. Further, the mass flow meter 4 has a strain amount detection unit 4d so as to detect a twist generated between the inflow side and the outflow side of the bent pipe 4c due to the Coriolis force generated by the vibration of the bent pipe 4c. The mass of turbid water can be calculated from the detected value. Further, the mass flow meter 4 is provided with a pickup unit 4e for detecting vibration of one outflow pipe 4b of the pipe constituting the measurement unit. From the natural frequency of the outflow pipe 4b, the outflow pipe 4b containing muddy water is detected. The mass per unit volume, the mass per unit volume of muddy water, and the density of muddy water are calculated as digital values from this mass and sent to the calculation unit 9.
[0009]
The calculation unit 9 includes an external input / output unit 9a for inputting each detection signal from the level meter 2b, the strain amount of the bent pipe 4c and the density of muddy water, a control unit 9b for controlling various operations, and a solid calculated in advance. It comprises an input unit 9c for inputting various information such as the true specific gravity of foreign matter or an operation command signal such as an operation start / stop signal, a storage unit 9d for storing various information, and a display unit 9e for displaying mass or turbidity. ing.
[0010]
As shown in FIG. 4, the storage unit 9d stores an optimum injection amount of the flocculant with respect to the turbidity for each predetermined width of the turbid water sample. This optimum injection amount is obtained by experiment as a boundary value at which the flocculant is directly discharged without agglomerating solid foreign matters for each turbidity, and this is backed up by a battery or the like.
[0011]
When the muddy water is above the lowest water level of the raw water tank 2 and the lowest water level detection signal from the level meter 2b is on, the control unit 9b operates an operation start signal from an operation switch (not shown). Is configured to be in a receivable state. The control unit 9b operates the raw water pump 5, the circulation pump 3 and the coagulant pump 8a when receiving an operation start signal from the operation switch, and receives the stop signal from a stop switch (not shown). The circulation pump 3 and the flocculant pump 8a are stopped. Further, after the control unit 9b receives the operation start signal, when the muddy water is less than the lowest water level of the raw water tank 2 and the lowest water level detection signal from the level meter 2b is turned off, the highest water level from the level meter 2b is turned off. The raw water pump 5, the circulation pump 3, and the coagulant pump 8a are stopped until the detection signal is turned on.
[0012]
While the raw water pump 5 is operating, the control unit 9b reads the density of turbid water sent to the external input / output unit 9a at regular intervals, calculates the turbidity of turbid water mixed with solid foreign matters from the following equation, While temporarily storing in the memory | storage part 9d, the moving average of these values is calculated every predetermined number of times, and this is temporarily stored in the memory | storage part 9d as average turbidity.
Turbidity = {(density−true specific gravity of liquid) × true specific gravity of turbidity component / (true specific gravity of turbidity component−true specific gravity of liquid)} × 10 ⁶
However, in the case of turbid water, the true specific gravity of the liquid is the specific gravity of water and is 1.000.
[0013]
In addition, the control unit 9b calls the average turbidity stored in the storage unit 9d at regular intervals, the two turbidities sandwiching the average turbidity from the turbidity stored in advance, and the coagulant corresponding to them. The injection amount is called, and the optimum injection amount of the flocculant with respect to the average turbidity is calculated by average interpolation.
[0014]
In the said flocculant automatic injection apparatus, when the muddy water in the raw | natural water tank 2 decreases, an operator will operate a supply pump and will supply muddy water to the raw | natural water tank 2. FIG. After the turbid water is supplied to the raw water tank 2 above the lowest water level, when an operation start signal is transmitted from the operation switch, the raw water pump 5, the circulation pump 3 and the coagulant pump 8a are activated, and the mass flow meter is accordingly operated. 4 is also supplied with muddy water. During this time, as the turbid water passes through the inflow pipe 4a, the bent pipe 4c, and the outflow pipe 4b, each pipe vibrates. Among them, the vibration of the outflow pipe 4b is detected by the pickup unit 4e. Is calculated as a digital value, which is sent to the external input / output unit 9a of the arithmetic unit 9. In the calculating part 9, the density of this muddy water is read every fixed time simultaneously with the operation of the raw water pump 5. From the density of the muddy water and the true specific gravity of the solid foreign matter calculated in advance, the turbidity of the muddy water is calculated momentarily, and these are temporarily stored in the storage unit 9d. A moving average for each predetermined number of times is calculated from these turbidities, and this is temporarily stored in the storage unit 9d as the average turbidity.
[0015]
At the same time, with the operation of the raw water pump 5, turbid water is supplied from the raw water tank 2 via the mixer 7 to the storage tank 6, while the average turbidity temporarily stored in the storage unit 9d is called up at regular intervals. From the turbidity stored in advance in the storage unit 9d and the coagulant injection amount corresponding thereto, the turbidity sandwiching the average turbidity and the coagulant input amount corresponding to these turbidities are called. From these values, the optimum amount of flocculant injected for the average turbidity is calculated by average interpolation, and the flocculant pump 8a operates so that the amount of flocculant is injected into the storage tank 6 through the mixer 7. . For this reason, an optimum amount of the flocculant is injected into the storage tank 6 via the mixer 7, and the solid foreign matter is aggregated without being wasted, and the aggregated and precipitated solid foreign matter is removed. Water is sent to a filter press device (not shown), and solid foreign substances contained in the treated water are almost removed by this filter press device, and only fresh water is discharged into the river.
[0016]
【The invention's effect】
As described above, the present invention obtains an optimum amount of flocculant injected for each turbidity of a predetermined width from a liquid sample mixed with solid foreign matters, and stores these in advance, while vibration of the pipe when the liquid passes through The mass of the pipe containing the liquid is calculated from the mass, the mass of the liquid is calculated from the mass, the density of the liquid is calculated from the mass, the turbidity of the liquid is calculated from the density, and the turbidity of the liquid is sandwiched from the turbidity stored in advance. Value and the flocculant injection amount corresponding to these values are called up, and the optimum flocculant injection amount for the turbidity of the liquid is calculated from these values. In addition to being able to inject the agent and discharging only fresh water that does not contain solid foreign matter to the river, etc., there is an advantage that the flocculant is not mixed with the fresh water and is not wasted.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a flocculant automatic injection device according to the present invention.
FIG. 2 is a block diagram showing a configuration of a calculation unit of the mass flow meter according to the present invention.
FIG. 3 is a schematic explanatory diagram of each pipe constituting the measurement unit of the mass flow meter according to the present invention.
FIG. 4 is a plot diagram showing the optimum amount of flocculant injected with respect to turbidity according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Flocculant automatic injection apparatus 2 Raw water tank 2a Filter part 2b Level meter 3 Circulation pump 4 Mass flow meter 4a Inflow pipe 4b Outflow pipe 4c Bending pipe 4d Strain amount detection part 4e Pickup part 5 Raw water pump 6 Reservoir 7 Mixer 8 Aggregation Agent storage tank 8a Coagulant pump 9 Calculation unit 9a External input / output unit 9b Control unit 9c Input unit 9d Storage unit 9e Display unit

Claims (1)

A bent pipe is arranged between the inflow pipe and the outflow pipe that are arranged in a straight line, and the liquid mixed with solid foreign substances from the inflow pipe passes through the bent pipe and is discharged from the outflow pipe. While calculating the density of the liquid mixed with solid foreign substances from the natural frequency, and calculating the turbidity of the liquid from this density and the true specific gravity of the solid foreign substances calculated in advance,
The optimum flocculating agent injection amount corresponding to the turbidity of the liquid is calculated from the calculated turbidity of the liquid and the optimal flocculating agent injection amount with respect to the turbidity stored in advance. Flocculant automatic injection device.

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