JP2000325940A - Adjustable-speed submerged electric agitator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adjustable-speed submerged electric agitator capable of always keeping agitation flow velocity in an agitation tank almost constant while being continuously worked, even if the agitation tank has a large water- level fluctuating width, being efficient due to low waste of energy, and capable of saving electric power consumption to be low in running cost. SOLUTION: An adjustable-speed submerged electric agitator is provided with a plurality of water level sensors 2 which are arranged so as to gradually sense water-level fluctuation in an agitation tank 1, a control device 3 which receives a receiving signal from one of the water level sensors 2, which sensed the water level in the tank, and sends a control signal to an inverter 5 so as to get the number of rotations approximate to a corresponding point on a preset operation curve, an inverter 5 which receives the control signal from the control device 3 to supply a frequency source corresponding to the signal, a submersible motor 6 which receives the frequency source from the inverter 5 and rotates at the number of rotations corresponding to the water-level fluctuation in the agitation tank 1, and agitating vanes 7 which are fitted to the derived end of the rotary shaft of the submersible motor 6 to rotate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable-speed underwater electric stirring apparatus used in a stirring tank having a large inflow range with unstable inflow conditions such as a flow control tank in a water treatment facility.

[0002]

2. Description of the Related Art Conventionally, an underwater electric mixer having a capacity to obtain sufficient stirring when a tank is full of water has been continuously operated at a rated value. Therefore, in a stirring tank with unstable inflow conditions such as a flow control tank in a water treatment facility and a large fluctuation in water level, the stirring flow velocity in the tank gradually increases as the water level decreases, and the water level in the tank and the mixer inlet A large amount of air is sent into the treated water by suction of the vortex from the nozzle, and the anaerobic agitation of the next process is adversely affected because the original purpose of anaerobic stirring cannot be performed, and the vortex is sucked from the mixer suction port. As a result, abnormal vibration is generated, and a serious accident such as breakage of a shaft, a guide ring, or the like is caused. In addition, at the time of increasing water in the tank, the stirring flow rate in the tank gradually decreases as the water level increases,
The function of preventing sedimentation of the sediment and the function of equalizing the liquid quality will be lost. As described above, a mixer having a constant rotation speed cannot maintain a constant stirring flow rate with respect to fluctuations in the water level, so that a large amount of energy is wasted and inefficiency, and a large amount of power is wasted. become.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stirrer having a large fluctuation in the water level and a continuous operation at a rotation speed corresponding to the fluctuation of the water level so that the stirring flow rate in the tank can always be kept substantially constant. It is an object of the present invention to provide a variable-speed underwater electric stirring device that is efficient, consumes less power, and has a low running cost.

[0004]

In the variable-speed underwater electric stirring apparatus according to the present invention, a plurality of water level sensors arranged to detect a water level change in the stirring tank in a stepwise manner, and a water level in the tank among the water level sensors is provided. A control device that receives a signal transmitted from one water level sensor that senses the pressure level and performs step control of an inverter corresponding to the detected water level, and a frequency power supply that receives a transmission signal from the control device and responds to the signal An underwater motor driven by the number of rotations corresponding to the fluctuation of the water level in the agitation tank upon receiving power from the inverter, and a stirring blade that rotates while being fitted to a leading end of a rotation shaft of the underwater motor. And

[0005]

When the controller receives a transmission signal from one water level sensor that senses fluctuations in the water level in the agitation tank, the rotation speed approximated to the predetermined point on the curves in FIGS. 2 and 3 is obtained. A control signal is transmitted to the inverter so that the inverter receives the controlled signal and supplies a frequency power corresponding to the signal to the submersible motor. It is driven by the corresponding rotation speed to generate a stirring action in the tank. When the water level in the tank becomes low, the frequency power corresponding to the signal from the lower water level sensor that detected the drop in the water level is supplied to the underwater motor, and the stirring action is weakened by the low-speed rotation. When the water level rises, the frequency power corresponding to the signal from the upper water level sensor that detects the rise in water level is supplied to the underwater motor, and the stirring action is strengthened by high-speed rotation, and the stirring flow rate in the tank is kept relatively constant at all times. You will be drowned.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a stirring tank, 2... 2 are a plurality of water level sensors arranged so as to detect a change in water level in the stirring tank 1 in a stepwise manner. An ON-OFF type is used. Reference numeral 3 denotes a control device interposed between each of the water level sensors 2... 2 and an inverter 5 described later.
2 and a control signal is transmitted to the inverter 6 so as to obtain a predetermined rotational speed approximate to the corresponding point on the curves in FIGS. 2 and 3. Reference numeral 6 denotes an inverter which receives a control signal from the control device 3 and supplies frequency power corresponding to the signal, and 6 receives power from the inverter 5 and drives at a rotation speed corresponding to a water level fluctuation in the stirring tank 1. It is desirable that the motor be a submersible motor and be of a DC type, but the present invention can be applied to an AC type. Reference numeral 7 denotes an agitating blade that is fitted to the rotating shaft leading end of the underwater motor 6 and rotates.

[0008] When the control device 3 receives a transmission signal from one water level sensor 2 which senses fluctuations in the water level in the stirring tank 1,
A control signal is transmitted to the inverter so as to obtain a rotation speed approximated to a predetermined point on the curves of FIGS. 2 and 3 which has been determined in advance, and the controlled signal is received by the inverter 5 and the corresponding signal is received. The frequency power is supplied to the underwater motor 6, and upon receiving the power, the underwater motor 6 is driven at a rotation speed corresponding to the water level fluctuation in the stirring tank 1 as shown in FIG. When the water level in the tank becomes low, the frequency power corresponding to the signal from the lower water level sensor 2 that has detected the low water level is supplied to the underwater motor 6, and the underwater motor 6 is rotated at a low speed and the stirring action is weakened. When the inside of the tank has a high water level, the frequency power corresponding to the signal from the upper water level sensor 2 that has detected the rising water level is supplied to the submersible motor 6, and the submersible motor 6 rotates at high speed and the stirring action is performed. As shown in FIG. 3, the stirring flow rate in the tank is kept almost constant at all times.

[0009]

According to the variable-speed underwater electric stirring apparatus of the present invention, even in a stirring tank having a large fluctuation in water level, the stirring flow rate in the tank can be kept almost constant by continuous operation to perform efficient stirring operation. As a result, the average number of revolutions is lower than that of the rated operation, so that the power consumption can be reduced and the wear of the movable part is reduced, so that the life can be extended. Further, as a derivative effect of low-speed rotation at low water level, vortex suction is smaller than in rated operation, and damage to the rotating shaft and guide ring due to abnormal vibration is not caused. Furthermore, the entrainment of air at the time of the low water level is reduced, and the anaerobic treatment in the next step in the water treatment facility is not adversely affected. As described above, the running cost can be reduced by the efficient operation, the maintenance cost is excellent, and the operation speed does not depend on the power supply frequency. Therefore, the stirring blade can be used in the 50 Hz / 60 Hz region, and therefore the manufacturing cost and This has the advantage of reducing inventory.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of the present invention.

FIG. 2 is a diagram illustrating the relationship between the water level in the tank and the motor rotation speed during operation of the variable speed underwater electric stirring device according to the present invention.

FIG. 3 is a diagram illustrating the relationship between the water level in the tank and the stirring flow rate during operation of the variable speed underwater electric stirring device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 stirring tank 2 water level sensor 3 control device 5 inverter 6 underwater motor 7 stirring blade

Claims (1)

[Claims] 1. A plurality of water level sensors arranged so as to detect a water level fluctuation in a stirring tank in a stepwise manner, and a signal transmitted from one of these water level sensors that senses the water level in the tank is transmitted. A control device that receives and performs stepwise control of an inverter corresponding to the sensed water level, an inverter that receives a transmission signal from the control device and supplies frequency power corresponding to the signal, and receives power from the inverter. A submersible motor driven by a rotation speed corresponding to the water level fluctuation in the stirring tank, and a stirring blade that rotates while being fitted to a rotating shaft leading end of the underwater motor. Electric stirrer