JP2007046489A - Submerged pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a submerged pump miniaturizing a water level detection sensor and preventing erroneous operation due to attached matter on a detection electrode without providing a grounding electrode. <P>SOLUTION: The submerged pump has a capacitance sensors 11, 12 attached on a attachment rod 9 extending in an up-and-down direction and supported by a pump body 1a, and is driven and controlled according to detection or non-detection of water level by the capacitance sensors 11, 12. The capacitance sensors 11, 12 are provided with detection electrodes 11a, 12a for detecting the water level and oscillation circuits 11b, 12b liquid-tightly covered by insulating material. The water level is detected by detecting change of stray capacitance 20, 21 between the detection electrodes 11a, 12a and oscillation circuits 11b, 12b or capacitance of the detection electrodes 11a, 12a themselves. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a submersible pump that is installed in a storage tank such as a wastewater treatment tank and drains water in the tank.

  Conventionally, as this type of submersible pump, a lower float switch as a lower water level detection sensor is attached to the outer lower part of the pump body, and an upper float switch as an upper water level detection sensor is attached to the outer upper part of the pump body via a mounting rod. If it is installed and the upper float switch is activated to detect the starting water level when the water level rises, the submersible pump is activated to drain the water, and then the lower float switch is returned to the stop water level due to the lowering of the water level accompanying drainage. If it is detected, there is a structure in which the submersible pump is controlled to be stopped.

  There are also submersible pumps that perform drive control by attaching a plurality of float switches such as a lower float switch and an upper float switch to a mounting rod supported by the pump body (see, for example, Patent Document 1 and Patent Document 2). .

  However, in such a submersible pump using a float switch, since the switch unit is operated by the ups and downs of the float switch, the water level detection sensor is increased in size and the float that floats in the stored water is incurred. There is a problem in that the float switch does not smoothly move up and down due to entanglement of the moss and the like with the float switch, causing the float switch to malfunction.

  Therefore, as a compact water level detection sensor that does not require ups and downs like a float switch, a capacitance sensor that detects the water level by detecting that the capacitance has changed due to the difference in dielectric constant between water and air is used. A submersible pump has also been proposed (see, for example, Patent Document 3).

JP 2003-286888 A JP-A-6-241191 Japanese Patent No. 3314224

  However, according to the water level detection method using the conventional capacitance sensor as described above, one electrode of the capacitance sensor is configured as a detection electrode for a non-ground electrode, and the other electrode is configured as a ground electrode for grounding. The water level is detected by determining whether or not water is present based on a change in capacitance between the detection electrode and the ground electrode.

  Therefore, it takes time to configure the ground electrode, and when a conductive deposit adheres to the detection electrode and is short-circuited with the water surface, a malfunction occurs due to erroneous determination of water level detection due to a change in capacitance. There is a drawback.

  In view of these problems, an object of the present invention is to provide a submersible pump in which a water level detection sensor is downsized and malfunctions due to deposits on the detection electrode are prevented without providing a ground electrode.

  The technical means for solving the above problem is that a water level detection sensor is attached to a mounting rod extending in the vertical direction supported by the pump body, and is driven and controlled according to whether the water level is detected or not detected by the water level detection sensor. In the submersible pump, the water level detection sensor includes a detection electrode for detecting the water level and an oscillation circuit covered in a liquid-tight manner with an insulating material, and is a capacitance sensor without a ground electrode. is there.

  The capacitance sensor may have a structure in which an isolated electrode is used as the detection electrode.

  Further, the water level detection sensor has a circuit that converts any change among an oscillation frequency change, an oscillation amplitude change, an oscillation phase change, or an oscillation circuit power consumption change in the oscillation circuit into a current change. It is good also as a structure with which the information of the said change converted into the said current change is transmitted to the drive control apparatus which drive-controls a submersible pump through the electric wire for power supply with respect to a water level detection sensor.

  The upper surface of the water level detection sensor may be formed in a tapered shape that gradually becomes narrower in the upward direction.

  Furthermore, it is good also as a structure where the said water level detection sensor is attached to the said attachment rod so that height adjustment is possible to an up-down direction.

  The mounting rod is formed of a cylindrical pipe body having a vertical groove, and the water level detection sensor is inserted into the mounting rod so as to be adjustable in height, and the water level detection sensor is fixed to the mounting rod. It is good also as a structure provided with the fixing means.

  Furthermore, the detection electrode may be covered with an insulating material in a liquid-tight manner.

  As described above, according to the submersible pump of the present invention, the water level detection sensor includes the detection electrode for detecting the water level and the oscillation circuit covered in a liquid-tight manner with the insulating material, and does not provide the ground electrode. Since it is structured as a capacitance sensor, the water level detection sensor can be downsized compared to conventional float switches, and since there is no ground electrode, malfunction due to deposits as in the past Can also be effectively prevented.

  In addition, if the capacitance sensor has an isolated electrode as the detection electrode, the water level can be detected by the change in the stray capacitance around the detection electrode or the capacitance of the detection electrode itself. It is difficult to be affected by deposits and can effectively prevent malfunctions due to deposits.

  Further, the water level detection sensor is provided with a circuit that converts any of the change in the oscillation frequency in the oscillation circuit, the change in the oscillation amplitude, the change in the oscillation phase, or the change in the power consumption of the oscillation circuit into a current change. If the structure is such that the change information converted into the current change through the power supply wire for the water level detection sensor is transmitted to the drive control device that drives and controls the submersible pump, the power supply wire is used as the information transmission wire. This eliminates the need for separate wiring and reduces the weight of the wire.

  In addition, if the upper surface of the water level detection sensor has a taper shape that becomes gradually narrower in the upward direction, accumulation of impurities and the like on the upper surface of the water level detection sensor can be effectively prevented.

  Further, if the water level detection sensor is attached to the mounting rod so that the height can be adjusted in the vertical direction, the adjustment of the starting water level and the like can be easily performed by adjusting the height of the water level detection sensor.

  The mounting rod is formed of a cylindrical pipe body having a split groove in the vertical direction, and the water level detection sensor is inserted into the mounting rod so that the height can be adjusted, and fixing means for fixing the water level detection sensor to the mounting rod is provided. Compared to the conventional structure in which the water level detection sensor is mounted outside, the water level detection sensor is arranged in the mounting rod, so the structure is more compact and the installation space is reduced. In addition, it is possible to effectively prevent entanglement and adhesion of foreign matter to the water level detection sensor.

  Furthermore, if the detection electrode is also covered with an insulating material in a liquid-tight manner, rusting of the detection electrode and the influence of insulating deposits can be effectively prevented.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, a pump body 1a in a submersible pump 1 is, for example, a metal motor casing portion that houses a motor portion. 2 and a motor cover 3 made of, for example, resin or metal that covers the upper part of the motor casing 2, and a pump casing made of, for example, resin or metal that is arranged at the lower part of the motor casing 2 and houses the impeller Part 4.

  In addition, a cylindrical suction port cover body 5 having a plurality of communication openings 5a formed on the peripheral surface is disposed below the pump casing portion 4 so as to surround the suction port of the pump casing portion 4. A drain pipe 6 is connected to the discharge part on one side of the pump casing part 4.

  Then, an attachment rod 9 made of an insulating resin pipe or the like having an appropriate length is attached and fixed to a side portion of the motor cover portion 3 in the pump body 1a with an axial center in the vertical direction. Has been. As a mounting structure using the support bracket 8, a known structure such as a structure in which the periphery of the mounting rod 9 is held and tightened loosely may be adopted as appropriate.

  An upper capacitance sensor 11 and a lower capacitance sensor 12 as water level detection sensors for detecting the start water level and the stop water level are adjustable in the vertical direction at the upper and lower portions of the mounting rod 9, respectively. Installed on.

  Each of the capacitance sensors 11 and 12 is provided with detection electrodes 11a and 12a at the lower end portion so as to be exposed to the outside, and an LC oscillation circuit or the like as shown in FIG. 4 is provided above the detection electrodes 11a and 12a. The oscillation circuits 11b and 12b and the current control circuits 11c and 12c include columnar sensor circuit portions 11d and 12d molded with an insulating resin as an insulating material, and the upper surfaces of the sensor circuit portions 11d and 12d are directed upward. Thus, the inclined surfaces 11e and 12e are formed in a conical taper shape that gradually becomes narrower, and electric wires 13 and 14 composed of two lines for power supply are drawn out from the center. Each of the oscillation circuits 11b and 12b and the current control circuits 11c and 12c is structured to be liquid-tightly covered with a resin mold.

  In addition, cylindrical sensor mounting portions 11f and 12f into which mounting rods 9 are inserted are provided on one side portions of the sensor circuit portions 11d and 12d in the respective capacitance sensors 11 and 12, and the sensor circuit portions 11d and 12d. The resin mold is integrally formed of the same resin material.

  Then, fixing screws 15 and 16 are screwed into the height direction intermediate portions of the sensor mounting portions 11f and 12f, respectively, and the fixing screws 15 and 16 are screwed out to be loosened. The portions 11f and 12f can be adjusted in the vertical direction with respect to the mounting rod 9, and the fixing screws 15 and 16 are screwed and fastened so that the shaft portions of the fixing screws 15 and 16 are moved into the sensor mounting portions 11f and 12f. And is fixed to the outer peripheral surface of the mounting rod 9 by being pressed and engaged.

  Further, the other ends of the electric wires 13 and 14 connected to the electrostatic capacitance sensors 11 and 12 are connected to a drive control device 18 for driving and controlling the submersible pump 1 while being built in the motor cover 3. ing.

  The capacitance sensors 11 and 12 indicate that the capacitance has changed due to the difference in dielectric constant between water and air depending on whether or not water is present around the detection electrodes 11a and 12a. It is set as the structure which detects and detects a water level.

  That is, as shown in FIG. 4, each of the capacitance sensors 11 and 12 includes detection electrodes 11a and 12a, and oscillation circuits 11b and 12b that generate an oscillation or a repetitive pulse at a period determined by a circuit constant of a circuit component. Current control circuits 11c, 12c for converting the oscillation frequency in the oscillation circuits 11b, 12b into current changes, and for changing the power supply current of the oscillation circuits 11b, 12b and the conversion circuit in accordance with the oscillation frequency changes. The oscillation frequency information transmitted from the current control circuits 11c and 12c through the wires 13 and 14 is converted into the current value by the upper current determination circuit 18a and the lower current determination circuit 18b of the drive control device 18. It is determined whether the water level has reached the start water level or the stop water level, and the pump control is performed according to the water level determination signal. It is configured to control to drive or stop the water pump 1 by the circuit 18c.

  In the present embodiment, the oscillation frequency of the oscillation circuits 11b and 12b in the capacitance sensors 11 and 12 is determined between the detection electrodes 11a and 12a protruding from the sensor circuit portions 11d and 12d and the oscillation circuits 11b and 12b. Are the stray capacitances 20 and 21 in a state where there is water around the detection electrodes 11a and 12a, and the oscillation frequency is adjusted to be a high frequency of about 20 MHz. Therefore, the oscillation frequency changes depending on whether the surroundings of the detection electrodes 11a and 12a are water or air.

  The oscillation frequency in the oscillation circuits 11b and 12b may be a high frequency that can be detected by the stray capacitances 20 and 21 between the detection electrodes 11a and 12a and the oscillation circuits 11b and 12b.

  The present embodiment is configured as described above. When the submersible pump 1 is installed in the waste water treatment tank, the power is always supplied through the electric wires 13 and 14, and the electrostatic capacitance sensors 11. , 12 to measure the water level.

  As shown in FIG. 1, when the water level H in the waste water treatment tank is below the upper capacitance sensor 11, it is detected that the lower capacitance sensor 12 is immersed in water. However, since the upper capacitance sensor 11 is not immersed in water, the upper current determination circuit 18a of the drive control device 18 determines that the starting water level has not been reached, and the submersible pump 1 is stopped by the pump control circuit 18c. Is controlled.

  Thereafter, when the water level H rises and reaches the position of the detection electrode 11a of the upper capacitance sensor 11 due to the inflow of water from an inflow pipe or the like, the stray capacitance 20 detected by the upper capacitance sensor 11 or The capacitance of the detection electrode 11a itself changes, and the oscillation frequency of the oscillation circuit 11b changes with the change of the capacitance of the stray capacitance 20 or the detection electrode 11a itself. In response to the change of the oscillation frequency, the current control circuit 11c changes the power supply current of the oscillation circuit 11b and the conversion circuit, and transmits the change information of the oscillation frequency to the upper current determination circuit 18a through the electric wire 13.

  The upper current determination circuit 18a determines the current value as change information of the oscillation frequency, determines that the water level has reached the startup water level, and outputs the determination signal to the pump control circuit 18c. The pump control circuit 18c receives this determination signal and activates the submersible pump 1.

  When the submersible pump 1 is started, the stored water in the waste water treatment tank is sucked through each communication opening 5 a of the suction port cover body 5, and the stored water is drained outside the tank through the drain pipe 6.

  Thereafter, due to the decrease in the water level H accompanying the drainage by the submersible pump 1, the drainage is continued even if the water level H falls below the position of the detection electrode 11 a of the upper capacitance sensor 11. When the water level H falls below the detection electrode 12a, the capacitance of the stray capacitance 21 or the detection electrode 12a itself detected by the lower capacitance sensor 12 changes, and this stray capacitance 21 or the detection electrode 12a itself is changed. The oscillation frequency of the oscillation circuit 12b changes with the change in the electrostatic capacity. In response to the change of the oscillation frequency, the current control circuit 12c changes the power supply current of the oscillation circuit 12b and the conversion circuit, and transmits the change information of the oscillation frequency to the lower current determination circuit 18b through the electric wire 14.

  The lower current determination circuit 18b determines the current value as change information of the oscillation frequency, determines that the water level has reached the stop water level, and outputs the determination signal to the pump control circuit 18c. The pump control circuit 18c receives this determination signal and stops the submersible pump 1.

  Thereafter, the water level H is stopped again until it reaches the detection electrode 11a of the upper capacitance sensor 11.

  The submersible pump 1 in the present embodiment is configured to be driven and controlled as described above. Since the capacitance sensors 11 and 12 are used as the water level detection sensors, compared with a conventional float switch. Miniaturization can be achieved. Further, due to the change in the capacitance of the stray capacitances 20 and 21 or the detection electrodes 11a and 12a themselves between the detection electrodes 11a and 12a, which are isolated electrodes in the capacitance sensors 11 and 12, and the oscillation circuits 11b and 12b. Since it is a method for detecting the water level, there is no need to provide a ground electrode as in the prior art. Further, even if a conductive substance or an insulating substance adheres to the detection electrodes 11a, 12a, Since it is affected only by the change in the capacitance of the stray capacitances 20 and 21 or the detection electrodes 11a and 12a itself, it is not easily affected by the conductive or insulating electrode deposits on the detection electrodes 11a and 12a, and the electrode deposits It is possible to effectively prevent malfunction.

  Further, the power supply wires 13 and 14 for the electrostatic capacitance sensors 11 and 12 are connected to the oscillation circuits 11b and 12b by the change in the capacitance of the stray capacitances 20 and 21 or the detection electrodes 11a and 12a themselves. The structure is also used as an information transmission wire for transmitting information, and there is no need for separate wiring, and the weight of the wires 13 and 14 as a whole can be reduced.

  Furthermore, since the upper surfaces of the sensor circuit portions 11d and 12d in the respective capacitance sensors 11 and 12 are formed in a tapered shape that gradually becomes narrower in the upward direction, the capacitance sensors 11 and 12 Accumulation of garbage and the like on the upper surface can be effectively prevented, and malfunction caused by garbage and the like can be effectively prevented.

  In addition, since the capacitance sensors 11 and 12 are attached to the mounting rod 9 so that the height can be adjusted in the vertical direction, the adjustment of the start water level and the stop water level can be performed by adjusting the height of the capacitance sensors 11 and 12. Easy to do.

  The attachment rod 9 is not limited to a pipe body, and may be a solid rod shape.

  5 to 7 show a second embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  That is, in the present embodiment, the mounting rod 9 is constituted by a cylindrical pipe body having a vertical dividing groove 9a, and the electrostatic capacitance sensors 11 and 12 are inserted into the mounting rod 9 so as to be adjustable in height. It is supposed to be a structure. Further, fixing screws 23 and 24 as fixing means are screwed to the side surfaces of the sensor circuit portions 11d and 12d in the electrostatic capacitance sensors 11 and 12 so as to be able to advance and retract.

  Then, as shown in FIG. 7, the shaft portions of the fixing screws 23 and 24 are arranged at the position of the dividing groove 9a, and by fastening the fixing screws 23 and 24, the fixing screws 23 and 24 and the sensor circuit portions 11d and 12d The mounting rod 9 is fixed in a clamped state, and the mounting screws 9 and 24 are loosened to release the clamped state of the mounting rod 9 so that the height can be adjusted.

  In the present embodiment, the outer diameters of the detection electrodes 11a and 12a are smaller than the outer diameters of the sensor circuit portions 11d and 12d. Other structures are the same as those in the first embodiment.

  Therefore, in this embodiment, the same effects as those of the first embodiment are obtained, and the electrostatic capacity sensors 11 and 12 are arranged in the mounting rod 9, so that the first embodiment is the same as in the first embodiment. Compared with the structure in which the electrostatic capacity sensors 11 and 12 are arranged outside, the structure is more compact, the installation space can be reduced, and entanglement and adhesion of foreign matter to the electrostatic capacity sensors 11 and 12 are also achieved. There is an advantage that can be effectively prevented.

  In each of the above embodiments, the detection electrodes 11a and 12a are exposed to the outside. However, each of the detection electrodes 11a and 12a is liquid-tight with an insulating material such as a resin mold as in the oscillation circuits 11b and 12b. In this case, the waterproof structure can effectively prevent the detection electrodes 11a and 12a from being rusted, and can also effectively prevent the influence of insulating deposits.

  Further, the mounting rod 9 may be provided with a scale for adjusting the height. In this case, the starting water level, the stop water level, etc. are detected by the mounting position of the capacitance sensors 11 and 12 on the mounting rod 9 by the scale. The water level can be easily confirmed, and there is an advantage that the start water level and the stop water level can be easily adjusted.

  Furthermore, in each of the above-described embodiments, the structure in which the capacitance sensors 11 and 12 are attached to the upper and lower two positions of the mounting rod 9 is shown. It is good also as a structure to attach. Two submersible pumps with capacitive sensors attached at two locations and two submersible pumps with capacitive sensors attached at three locations are installed in the wastewater treatment tank so that they can be operated alternately as before. Drive control can also be performed.

  Moreover, although the structure provided with the drive control apparatus 18 in the pump main body 1a is shown, it is good also as a structure installed in the control panel installed on the ground.

  Furthermore, although the structure which detects the water level by detecting the information of the oscillation frequency change in the oscillation circuits 11b and 12b is shown, the oscillation amplitude change, the oscillation phase change in the oscillation circuits 11b and 12b, or the oscillation circuit It may be configured to detect the water level by detecting any information such as a change in power consumption, and is not limited to the method of the embodiment.

It is a side view which shows the submersible pump concerning the 1st Embodiment of this invention. It is the principal part enlarged view. It is the III-III sectional view taken on the line of FIG. It is the same control block diagram. It is a principal part disassembled perspective view concerning 2nd Embodiment. It is a perspective view of the same assembly state. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Submersible pump 9 Mounting rod 9a Split groove 11 Upper electrostatic capacitance sensor 11a Detection electrode 11b Oscillation circuit 11c Current control circuit 11d Sensor circuit part 11e Inclined surface 11f Sensor attachment part 12 Lower electrostatic capacity sensor 12a Detection electrode 12b Oscillation circuit 12c Current Control circuit 12d Sensor circuit portion 12e Inclined surface 12f Sensor mounting portion 13 Electric wire 14 Electric wire 15 Fixing screw 16 Fixing screw 18 Drive controller 18a Upper current determination circuit 18b Lower current determination circuit 18c Pump control circuit 20 Floating capacitance 21 Floating capacitance 23 Fixed screw 24 fixing screws

Claims (7)

In a submersible pump in which a water level detection sensor is attached to a mounting rod that extends in the vertical direction supported by the pump body, and is driven and controlled according to whether the water level is detected or not detected by the water level detection sensor.
The submersible pump characterized in that the water level detection sensor is a capacitance sensor that includes a detection electrode for detecting a water level and an oscillation circuit covered in a liquid-tight manner with an insulating material, and does not include a ground electrode. . The submersible pump according to claim 1,
The electrostatic capacity sensor uses an isolated electrode as the detection electrode. The submersible pump according to claim 1,
The water level detection sensor is provided with a circuit that converts any one of a change in oscillation frequency, an amplitude change in oscillation, a phase change in oscillation, or a change in power consumption of the oscillation circuit into a current change in the oscillation circuit. The submersible pump is characterized in that the change information converted into the current change is transmitted to a drive control device for driving and controlling the submersible pump through a power supply electric wire for the water level detection sensor. The submersible pump according to any one of claims 1 to 3,
The submersible pump, wherein an upper surface of the water level detection sensor is formed in a tapered shape that gradually becomes narrower in an upward direction. The submersible pump according to any one of claims 1 to 4,
The submersible pump, wherein the water level detection sensor is attached to the attachment rod so as to be adjustable in height in the vertical direction. The submersible pump according to any one of claims 1 to 5,
The mounting rod is composed of a cylindrical pipe body having a split groove in the vertical direction, and the water level detection sensor is inserted into the mounting rod so as to be adjustable in height, and the water level detection sensor is fixed to the mounting rod. The submersible pump characterized by being equipped with. The submersible pump according to any one of claims 1 to 6,
The submersible pump, wherein the detection electrode is also covered with an insulating material in a liquid-tight manner.

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