JP2007327368A - Automatic water supply pump drought protection device - Google Patents

Abstract

The present invention provides a pump drought protection device for an automatic water supply device that prevents the temperature of a pump unit and an electric motor from excessively rising when a drought condition continues.
The pump drought protection device of the present invention detects the motor temperature of an electric motor 2ba during a drought pump operation, and extends the interval time when the motor temperature in a drought condition is equal to or higher than a predetermined value, thereby drought. Until the state is resolved, the temperature of the pump unit 2a and the electric motor 2b is not excessively increased.
[Selection] Figure 1

Description

  The present invention relates to a pump drought protection device for an automatic water supply apparatus that protects a pump from a drought due to, for example, a well water level temporarily falling.

  Many automatic water supply systems that supply well water are installed in the wells with water pumps composed of electric motor-driven submersible pumps or land pumps, and the capacity of the pumps is controlled by the control unit according to demand (inverters, etc.) The desired water supply amount and water supply pressure are ensured.

  By the way, the water level of a well fluctuates depending on the state of underground water veins and the level of groundwater pumping. For this reason, during the water supply operation, the water level of the well may fall to the drought level.

  However, when the water level reaches the drought level during the water supply operation, the pump part of the water supply pump is only operated to agitate the remaining water in the pump casing, and an excessive (abnormal) temperature rise occurs. It will make the part worse. Especially for submersible pumps, when the electric motor is exposed to the atmosphere, the cooling action of the well water is lost, so the temperature of the electric motor rises excessively (abnormally) and the electric motor itself deteriorates or forms a peripheral wall of the well. There is a risk of deforming the casing.

As a countermeasure, a technique for protecting a water supply pump as disclosed in Patent Document 1 from a drought state has been proposed. When the well level drops to the drought level during the water supply operation, the technology stops the operation of the water supply pump and restarts the water supply pump after a predetermined interval time has elapsed, so that the well level is restored. Until then, the pump is repeatedly stopped and restarted.
Japanese Patent Laid-Open No. 10-213074

  By the way, in the electric motor, the temperature rise due to the influence of the previous no-load operation remains at the restart stage.

  For this reason, when the water supply pump is restarted and the no-load operation is performed again from the drought state, the electric motor has an excessive (abnormal) temperature due to the additional temperature increase in addition to the previous temperature increase. May rise. In particular, repeated restarting may cause an excessive temperature increase because the electric motor itself gradually increases in temperature due to the influence of the previous no-load operation.

  If the temperature rises excessively, the electric motor itself may be deteriorated or the well casing may be deformed.

  Accordingly, an object of the present invention is to provide a pump drought protection device for an automatic water supply apparatus that can prevent the temperature of a pump unit and an electric motor from excessively rising when a drought state continues.

  In order to achieve the above object, the invention of claim 1 is a temperature detecting means for detecting a motor temperature of an electric motor during a drought pump operation, and an interval time when the motor temperature in a drought condition is a predetermined value or more. The system is provided with an interval time changing means for extending the interval.

  The invention according to claim 2 uses, as the temperature detecting means, a motor current value detecting means for detecting the motor current of the electric motor during the drought pump operation, and the interval time changing means includes a motor in the first drought state. A reference current value storage means for storing a current value; a variable current value detection means for detecting a motor current value after the second time when the drought condition continues; and a motor current value detected at the first time when the drought condition continues. A configuration having motor current fluctuation detecting means for comparing the detected motor current values for the second and subsequent times and interval setting means for extending the interval time when the difference between the compared motor current values is a predetermined value or more is adopted.

  The invention according to claim 3 uses, as the temperature detecting means, motor current value detecting means for detecting the motor current of the electric motor during the drought pump operation, and the interval time changing means includes the motor in the first drought state. Reference current value storage means for storing the current value, fluctuation current value detection means for detecting the motor current value for the second and subsequent times when the drought condition continues, and detection of the first motor current value each time the drought condition continues A configuration having a fluctuation rate calculating means for obtaining a change rate with the motor current value for the second and subsequent times and an interval setting means for extending the interval time according to the fluctuation rate when the obtained fluctuation rate is a predetermined value or more is adopted. .

  The invention of claim 4 detects the motor current value immediately before the pump operation in the drought state stops.

  According to the present invention, even if the drought condition continues, the electric motor-driven pump is excessively heated until the drought condition is eliminated by the control that extends the interval time. Does not rise.

  Therefore, drought protection of the electric motor driven pump can be continued with high reliability.

  In addition, when a structure that extends the interval time using a motor current value that exhibits the same behavior of the motor temperature is used, the interval time can be extended without using a dedicated component such as a temperature sensor. In addition, the interval time can be extended easily by using the preset extended interval time or by extending according to the rate of change of the motor current value. The interval time can be changed finely according to the situation. In particular, when the motor current value is used as a parameter for the motor temperature, the drought protection of the pump can be appropriately performed by using the motor current value immediately before the pump operation (the drought state), which is the newest information, is stopped.

[First Embodiment]
Hereinafter, the present invention will be described based on the first embodiment shown in FIG. 1 and FIG.

  FIG. 1 schematically shows an automatic water supply apparatus B in which a pump drought protection apparatus A is incorporated. In FIG. 1, reference numeral 1 denotes a well (intake source), and 2 denotes an electric motor-driven water supply pump installed in the well 1, for example, a submersible pump (water supply pump). In the figure, 2a represents a pump portion of the submersible pump 2, and 2b represents an electric motor for driving the pump portion 2a.

  On the other hand, in the automatic water feeder B, for example, a structure in which the water flow module 6 and the pump control unit 15 are housed in the casing 5 is used. The water flow module 6 includes a pressure sensor 10 that detects the pressure of a fluid flowing in the water flow pipe 9 and a water flow pipe 9 having one end portion as an inlet portion 7 and the other end portion as an outlet portion 8. The flow rate sensor 11 for detecting the flow rate is assembled. And the inlet part 7 is connected to the relay piping 12 extended from the discharge part of the submersible pump 2 via the joint part 7a. The outlet 8 is connected to a demand-side relay pipe 13 connected to the demand side, such as a faucet, through a joint portion 7b, and the well water discharged from the submersible pump 2 is sent to the relay pipe 13 through the water flow pipe 9. It is like that.

  The pump controller 15 includes a microcomputer (not shown). The controller 15 is connected to the electric motor 2b of the submersible pump 2, the pressure sensor 10, the flow sensor 11, and the like. The pump control unit 15 is set with a control program for water supply that controls the operation of the submersible pump 2 in accordance with the demand state detected by the pressure sensor 10 and the flow sensor 11. Furthermore, a protection program for drought that protects the submersible pump 2 from drought is set in the pump control unit 15.

The drought protection program is
-For example, a detection function for detecting when the submersible pump 2 operates in a drought state from the detection information of the pressure sensor 10 and the flow sensor 11 (equivalent to a pump drought state detection means)
When the operation in the drought state is detected, the operation of the pump is stopped and the pump is restarted after a predetermined interval time t has elapsed (corresponding to the pump drought protection control means),
A temperature detection function (corresponding to temperature detection means) for detecting the motor temperature (electric motor 2b) of the submersible pump 2 in a drought state;
-When the motor temperature in a drought condition is high (above a predetermined value), the interval time changing function that extends the interval time t (corresponding to the interval time changing means)
It is configured by combining.

  Among these, the detection function is formed by a program for detecting when the discharge water amount is equal to or less than a predetermined water amount and the discharge pressure is equal to or less than a preset lower limit pressure in order to detect a pump drought state.

  The pause operation function stops the operation of the submersible pump 2 for a predetermined time (interval time t) when a pump drought condition is detected, and after the elapse of the predetermined time (interval time t), the submersible pump It is formed by a program that resumes the operation of No. 2.

  The temperature detection function is equivalent to the motor temperature in which when the motor winding of the electric motor 2b generates heat, the winding resistance increases, and the drought current (no-load current) of the electric motor 2b decreases in inverse proportion to it. It is formed by a function using a changing motor current (winding current). Specifically, it is formed by a function of detecting a motor current value of the electric motor 2b in a drought state, and a function of detecting a motor current value immediately before the submersible pump 2 is stopped, which is the newest information.

  The interval time changing function detects a motor current value in the first (first time) drought state (corresponding to the reference current value storage means) and detects the motor current value flow after the second time when the drought state continues. A function (corresponding to the fluctuation current value detection means) and a function (corresponding to the motor current fluctuation detection means) for comparing the motor current value detected at the first time with the detected motor current value at the second and subsequent times whenever the drought state continues. ) And a function of extending the interval time t when the difference between the compared motor current values is equal to or greater than a predetermined value (corresponding to interval setting means). For the extension, a function of changing from the interval time t to the extension interval time t + α (a preset interval time longer than the interval time) is used. α indicates the extended time.

  The pump drought protection device A is configured from the pump control unit 15 in which such a protection function is set.

  The operation of this pump drought protection device A is shown in the flowchart of FIG. The operation of the pump drought protection device A will be described with reference to the flowchart.

  Assume that the water level of the well 1 is at the operating water level as shown in FIG. In this state, the well water is pumped up as desired by the operating submersible pump 2 and supplied to a faucet or the like.

  Assume that during such water supply operation, the water level in well 1 has dropped to the drought level in FIG. Then, the submersible pump 2 is exposed to the atmosphere, and a no-load operation is performed in which the remaining water in the pump casing is only stirred. Thereby, the temperature of the pump part 2a and the motor winding rises. That is, when a drought occurs, the temperature of each part of the submersible pump 2 increases.

  Here, in the operation at the time of drought, the amount of pump water is not more than a certain value, and the discharge pressure is not more than the set pressure value of the lower limit of water supply. For this reason, the pump control unit 15 detects from the detection signals from the pressure sensor 10 and the flow rate sensor 11 that the submersible pump 2 is operating in a drought state, as shown in step S1. That is, the detection of the pump drought condition is performed.

  At this time, if the occurrence of the pump drought condition is the first, that is, the first pump drought condition that occurs for the first time, the process proceeds to step S4, 5 from the determination of whether the pump drought condition is the first in step S2, and the submersible pump The second electric motor 2b is stopped, and the control is continued for the predetermined set interval time t. During the pause, the pump unit 2a and the electric motor 2b are protected from temperature rise (also depending on the pump unit 2a and the electric motor 2b being cooled in the atmosphere). The pump control unit 15 detects the motor current value I1 flowing through the winding of the electric motor 2b (submersible pump 2) as shown in step S3 immediately before the submersible pump 2 is stopped, and stores the current value I1 ( For use as a reference value). When the interval time t elapses, the electric motor 2b is energized, and the submersible pump 2 is restarted as shown in step S5.

  At this time, if the water level in the well 2 is restored, water supply by the submersible pump 2 is resumed.

  At this time, if the water level in the well 2 has not recovered, the submersible pump 2 is operated again with the pump water amount being not more than a certain value and the discharge pressure being not more than the set pressure value of the lower limit of water supply. That is, no-load operation is performed. Then, the pump control part 15 detects a pump drought state following the last time by the detection signal of the flow sensor 11 or the pressure sensor 10 at this time (step S1). Since the current pump drought state is the second detection in which the previous drought state is continued, the process proceeds from step S2 to step S3 through step S7, and then proceeds to the routine after step S7.

  After Step S7, the interval time is set to be extended using the time until the submersible pump 2 is stopped, and the process proceeds to the pump stop and restart. This routine will be described.

  Step S7 detects the motor current value In of the motor winding immediately before the submersible pump 2 stops.

  Here, when the resistance value of the motor winding of the electric motor 2b rises due to heat generation of the motor winding, there is a characteristic that the current during drought (no-load current) of the electric motor 2 decreases in inverse proportion to it. That is, the motor current value (current flowing through the motor windings) exhibits the same behavior as the temperature change of the submersible motor 2. Therefore, the motor current value is used as the motor temperature information.

  In the subsequent step S8, the motor temperature rises due to the motor current value I1 as the reference detected first time, the factor that the motor temperature rises due to the influence of the previous no-load operation, and the influence of the no-load operation of the current restart. The difference between the motor current value In and the factor is compared. At this time, if the difference is equal to or greater than a predetermined temperature value Δi (a value that distinguishes the temperature state of the electric motor 2) set in advance, the electric motor 2b is likely to cause an excessive temperature rise (abnormal temperature rise). It is determined that the interval time t has increased to step S9, and the interval time t is changed to the extended interval time t + α set longer than that. α indicates the extended time. Then, the submersible pump 2 is continuously stopped using the extension interval time t + α (step S10). When the interval time t elapses, the electric motor 2b is energized, and the submersible pump 2 is restarted as shown in step S11. When the difference falls below the predetermined temperature value Δi, the process proceeds to step S5, and the interval time t is not changed (because an excessive temperature rise does not occur).

  Thus, in order to protect the pump from drought, even if the submersible pump 2 is restarted and further restarted, if the motor temperature is above a predetermined temperature at which excessive temperature rise is likely to occur, the drought condition is resolved. Since the motor stop time is set long until the pump 2a and the electric motor 2b rise, abnormal temperature rise can be prevented.

  Therefore, drought protection of the water supply pump (electric motor drive pump) can be continued with high reliability.

  Moreover, the structure in which the motor current values I1 and In are used to extend the interval time does not require a dedicated component such as a dedicated temperature sensor. In addition, the interval time can be easily changed because the preset extended interval time t + α is used. In particular, when the motor current value immediately before the stop of the pump operation (the drought state), which is the newest information, is detected, appropriate pump drought protection can be performed.

[Second Embodiment]
FIG. 3 shows a main part of the second embodiment of the present invention.

  In the second embodiment, the inverter time can be extended according to the increase in the motor temperature, not the single extended interval time as in the first embodiment.

  In this routine, the interval time changing function shown in FIG. 2 is changed from step S7 to step S11 to step S20 to step S23 as shown in the flowchart of FIG. Specifically, in step S20, a function of performing a process of calculating the first motor current value I1 and the change rate Ik (I1 / In) of the detected Nth motor current value In every time the drought condition continues. (Corresponding to fluctuation rate calculation means) is used. In step S21, it is compared whether or not the obtained change rate Ik is equal to or higher than a predetermined change rate Δk (a value that distinguishes the temperature state of the electric motor 2). A function is used to determine whether or not there is a risk of temperature rise. In step S22, when the rate of change Ik at this time is equal to or greater than the predetermined rate of change Δk (when there is a risk of excessive temperature rise), a function is set to extend the interval time t according to the rate of change Ik. Is used. Specifically, a function of changing to a time obtained by multiplying the change rate Ik by an interval time t is used [(t) x (Ik)]. In other words, the interval setting means is configured from these steps S21 and S22, and when the fluctuation rate Ik is a predetermined value or more, the interval time t is extended according to the fluctuation rate Ik.

  Since steps S1 to S3, steps S4 to S7, and step S11 are the same as those in the first embodiment, the same reference numerals as those in the flowchart of FIG.

  Such a structure for setting the extension time α of the pump stop time can extend the interval time t finely according to the condition of the motor temperature. Moreover, since the interval time is extended in accordance with the fluctuation rate of the motor current values I1 and In, the interval time can be easily extended without using a dedicated component such as a dedicated temperature sensor. t can be set.

  In the first embodiment, the extension time may be changed as in the second embodiment (for example, the interval time according to the difference between the first motor current value I1 and the second and subsequent In). It is conceivable to change the time α of the extension of t).

[Third Embodiment]
FIG. 4 shows a main part of the third embodiment of the present invention.

  The third embodiment is not an automatic water supply device that supplies water with the submersible pump 15 as in the first embodiment or the second embodiment, but a land pump 25 (pump unit 25a, electric motor 25b) installed on land. The present invention is applied to an automatic water supply device that pumps well water using a water supply pump). However, in FIG. 4, the same parts as those in FIG.

  Such a water supply apparatus also has the same effect as the first and second embodiments.

  In addition, this invention is not limited to any embodiment mentioned above, You may implement in various changes within the range which does not deviate from the main point of this invention. For example, in the above-described embodiment, the present invention is used for a water supply device that pumps well water. However, the present invention is not limited thereto, and may be used for a water supply device that supplies water from other intake sources.

The figure which shows schematic structure of the automatic water supply apparatus which concerns on the 1st Embodiment of this invention. The flowchart explaining the effect | action of the drought protection apparatus integrated in the automatic water supply apparatus. The flowchart explaining the effect | action of the drought protection apparatus used as the principal part of the 2nd Embodiment of this invention. The figure which shows schematic structure of the principal part of the automatic water supply apparatus which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Submersible pump, 2a ... Pump part, 2b ... Electric motor, 10, 11 ... Pressure sensor, Flow rate sensor (Pump drought state detection means), 15 ... Pump control part (Pump drought protection control means, Temperature detection means, Interval time) Change means).

Claims (4)

A pump drought state detecting means for detecting when the electric motor-driven pump operates in a drought state;
When the operation of the electric motor-driven pump in the drought state is detected, the pump is stopped automatically, and after the elapse of a predetermined interval time, the pump has a drought protection control means for restarting the pump. In the pump drought protection device of water supply equipment,
Temperature detecting means for detecting the motor temperature of the electric motor during the drought pump operation;
A pump drought protection device for an automatic water supply apparatus, comprising: interval time changing means for extending the interval time when the motor temperature in the drought state is equal to or higher than a predetermined value. The temperature detecting means is constituted by a motor current value detecting means for detecting a motor current of the electric motor during a drought pump operation.
The interval time changing means is
Reference current value storage means for storing the motor current value in the first drought state;
Fluctuating current value detecting means for detecting the motor current value for the second and subsequent times when the drought condition continues;
Motor current fluctuation detecting means for comparing the first motor current value with the detected second and subsequent motor current values each time the drought condition continues;
2. The pump drought protection for an automatic water supply apparatus according to claim 1, further comprising interval setting means for extending the interval time when the difference between the compared motor current values is a predetermined value or more. apparatus. The temperature detecting means is constituted by a motor current value detecting means for detecting a motor current of the electric motor during a drought pump operation.
The interval time changing means is
Reference current value storage means for storing the motor current value in the first drought state;
Fluctuating current value detecting means for detecting the motor current value for the second and subsequent times when the drought condition continues;
A variation rate calculating means for obtaining a rate of change between the first motor current value and the detected second or subsequent motor current value each time the drought condition continues;
The automatic water supply pump according to claim 1, further comprising interval setting means for extending the interval time according to the fluctuation rate when the obtained fluctuation rate is a predetermined value or more. Drought protection device.   The said temperature detection means detects the motor electric current value just before the pump driving | running | working of a drought state stops, The pump drought protection apparatus of the automatic water supply apparatus of Claim 2 or Claim 3 characterized by the above-mentioned.

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