JP3570906B2 - Control device for submersible pump - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a submersible pump control device provided with a flow rate detection unit and performing constant control of an estimated terminal pressure of the submersible pump.
[0002]
[Prior art]
2. Description of the Related Art There is known a water supply system in which a submersible pump is dropped into water such as a well, and the water is pumped from the submersible pump.
[0003]
Such a submersible pump is automatically operated by a control device. For example, during the automatic operation of the submersible pump, if the flow detection unit is stuck in the ON state due to sand or the like, the control device considers that the water demand on the water supply demand side is continuing, and starts the pump. Driving continued without stopping.
[0004]
[Problems to be solved by the invention]
In such a water supply system, when the water is not used on the water supply demand side, the pump becomes a shut-off operation, and overheating may lead to burnout of the motor and eventually to melting of the well casing.
[0005]
To detect such a shutoff operation, the temperature of the pump housing may be detected.However, a temperature sensor is required to detect the temperature of the pump housing, and the detection of this temperature sensor is performed. There is a problem in that the cost must be increased because it must be performed all the time.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to provide a control apparatus for a submersible pump that can prevent a shutoff operation of a pump only by using an inexpensive flow rate sensor without performing temperature detection. To provide.
[0010]
[Means for Solving the Problems]
The control device for a submersible pump according to claim 1, further comprising: a flow detection unit configured to detect a flow rate discharged from the submersible pump; and a pressure detection unit configured to detect a pressure of water discharged from the submersible pump. the control apparatus submersible pump for controlling the pressure of the water discharge to a constant pressure, the operating frequency of the pump at the time during operation the water pump said flow rate detecting means is changed from oN to oFF normally less from Means for storing the output frequency of the submersible pump; determining means for determining whether or not the operating frequency of the submersible pump is equal to or lower than the output frequency for low water quantity for a predetermined time; and determining the operating frequency of the submersible pump by the determining means. When it is determined that the state equal to or less than the water amount output frequency has passed for a certain period of time, a pump stop unit that stops the pump and sets an emergency operation mode, Determining means for determining whether the on state of the flow rate detecting means has continued for a predetermined time or more after stopping the submersible pump by the pump stopping means; and determining that the on state of the flow rate detecting means has continued for a certain time or more. If it is determined that the pressure has been detected , a means for performing an abnormality display and a failure alarm is provided.Each time the pressure detecting means detects that the pressure is equal to or lower than the starting pressure, the submersible pump is started, and a preset value is set. During the forced operation time, while performing an emergency operation to stop the submersible pump after operation, in the emergency operation mode, constantly monitor the detection output of the flow rate detection means, when the flow rate detection means is turned off, The emergency operation mode is released.
[0011]
The control device for a submersible pump according to claim 2 is characterized in that in the emergency operation mode, the forced operation time from when the submersible pump is started is automatically extended from a preset set value .
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a control device of a submersible pump that performs constant control of an estimated terminal pressure. In FIG. 1, reference numeral 11 denotes a well. In this well 11, water 12 is stored.
[0014]
A submersible pump 13 is buried so as to be immersed in the water 12 of the well 11.
[0015]
The submersible pump 13 performs a process of sucking water stored in the well 11 and pumping it to the ground.
[0016]
That is, the discharge port of the submersible pump 13 is connected to one end of the check valve 15 via the pipe 14.
[0017]
The other end of the check valve 15 is connected to a water supply pipe 16.
[0018]
A flow sensor (FS) 17 is attached to the water supply pipe 16. The flow rate sensor 17 detects a flow rate flowing through the water supply pipe 16 on and off. In other words, when the flow rate flowing through the water supply pipe 16 is smaller than the minimum flow rate Io, an off signal is output, and when the flow rate flowing through the water supply pipe 16 is equal to or more than the minimum flow rate Io, the flow signal I is output as an ON signal.
[0019]
Further, a pressure tank 18 is connected to a downstream position of the flow sensor 17. The pressure P of the water supply pipe 16 is detected by the pressure sensor 19. The pressure signal P output from the pressure sensor 19 and the flow signal I output from the flow sensor 17 are output to the control unit 20.
[0020]
The control unit 20 is mainly configured by a CPU 20a and an inverter 20b. The inverter 20b outputs an operation signal whose frequency changes from fmin to fmax in order to control the rotation speed of a motor (not shown) for driving the submersible pump 13.
[0021]
The frequency of the operation signal output from inverter 20b is detected by output frequency detection unit 20c.
[0022]
20d is a timer for measuring the time. The timer 20d is composed of a plurality of timers capable of counting different times.
[0023]
Further, the control unit 20 is provided with a memory 20e for storing various data.
[0024]
Further, a display 21 for displaying an abnormality of the submersible pump 13 and an alarm 22 for warning the abnormality of the submersible pump 13 are connected to the control unit 20.
[0025]
By the way, the CPU 20a includes a ROM (read only memory) (not shown) that stores a control program for performing the control shown in the flowcharts of FIGS.
[0026]
Next, the operation of the embodiment of the present invention configured as described above will be described with reference to the flowchart of FIG.
[0027]
First, it is determined whether the underwater motor 13 is operating (step S1).
[0028]
If the determination in step S1 is "NO", a startup process described below is performed with reference to the flowchart of FIG. 4 for starting the submersible pump 13 (step S2). If the determination in step S1 is "NO", it means that the pressure P detected by the pressure sensor 19 has become equal to or lower than the starting pressure.
[0029]
On the other hand, if “YES” is determined in the determination in step S1, the timer 20d determines whether the forced operation time t1 has elapsed since the start processing described above is started (step S3). Here, the forced operation time t1 is defined as being within the forced operation time t1 by prohibiting the input of the flow rate signal I output from the flow rate sensor 17 within the forced operation time t1 after starting the submersible pump 13. Of the submersible pump 13 is forcibly operated.
[0030]
If the determination in step S3 is "YES", it is determined whether the flow signal I output from the flow sensor 17 has been turned off (step S4).
[0031]
If "YES" is determined in this step S4, that is, if it is determined that the output of the flow rate sensor 17 is turned off, the output frequency of the inverter 20b detected by the output frequency detection unit 20c is set to the low water output frequency. Is read into the memory 20e.
[0032]
Then, the submersible pump 13 is stopped (Step S6).
[0033]
By the way, if the determination in step S4 is "YES", that is, if it is determined that the flow rate signal I is ON, the output frequency of the inverter 20b detected by the output frequency detection unit 20c is set to a preset lower limit value. It is determined whether it is equal to (lower limit frequency) (step S7).
[0034]
If “NO” is determined in the determination in step S7, the process returns to step S4 described above.
[0035]
On the other hand, when it is determined “YES” in the determination of step S7, it is determined whether the flow rate signal I is off and the operation frequency of the inverter 20b is at the lower limit value (lower limit frequency) for a predetermined time T1. (Step S8).
[0036]
If the determination in step S8 is "YES", a process for forcibly stopping the submersible pump 13 is performed (step S9).
[0037]
That is, the fact that the state in which the operating frequency of the inverter 20b is at the lower limit value has continued for the predetermined time T1 should not be enough to turn on the flow signal I even when the submersible pump 13 is operating. However, when the flow signal I is on, it is determined that the flow sensor 17 is clogged with dust or the like and the on signal is erroneously output.
[0038]
Therefore, in such a case, it is determined that the shutoff operation of the submersible pump 13 is being performed, and the submersible pump 13 is forcibly stopped (step S9).
[0039]
As described above, according to the first embodiment, the state where the flow rate signal I is on and the operating frequency of the inverter 20b is at the lower limit (lower limit frequency) is the fixed time T1 (FIG. 6A). If the submersible pump 13 is continued, it is determined that the submersible pump 13 is in the shut-off operation, and the submersible pump 13 is forcibly stopped. Can be.
[0040]
Next, the operation of the second embodiment of the present invention will be described with reference to the flowchart of FIG. The second embodiment relates to the processing after the submersible pump 13 of FIG. 2 is forcibly stopped.
[0041]
First, it is determined whether the submersible pump 13 is stopped (step S11).
If the determination in step S11 is "YES", it is determined whether or not the flow signal I output from the flow sensor 17 is ON (step S12). If “NO” is determined in the determination in step S12, a startup process described below with reference to FIG. 4 is performed (step S13).
[0042]
On the other hand, when it is determined as “YES” in the determination of step S12, that is, when it is determined that the flow signal I output from the flow sensor 17 is on, the state is maintained for a certain time T2 [FIG. B) is passed (step S14). The determination of the elapse of the predetermined time T2 is performed by the timer 20d of the control unit 20.
[0043]
In other words, the fact that the flow signal I output from the flow sensor 17 is on even though the submersible pump 13 is stopped means that the flow sensor 17 is clogged with dust or the like and the flow signal I is erroneously turned on. Is displayed, the display 21 indicates that the submersible pump 13 is abnormal. Further, an alarm is output from the alarm 22 to warn that the submersible pump 13 is abnormal.
[0044]
Further, an emergency operation flag is set in the memory 20e of the control unit 20.
[0045]
Further, t2 (> t1) is set as the forced operation time (step S15).
[0046]
As described above, according to the second embodiment of the present invention, after the submersible pump 13 is forcibly stopped, the state in which the flow rate signal I output from the flow rate sensor 17 is on is kept for a certain period of time. When T2 is continued, the display 21 indicates that the submersible pump 13 is abnormal, and an alarm is output from the alarm 22. Therefore, the operator can know the abnormality of the submersible pump 13 without fail. it can.
[0047]
Next, the activation process will be described with reference to the flowchart of FIG. First, it is determined whether the pressure P of the water supply pipe 16 detected by the pressure sensor 19 is equal to or lower than the starting pressure Po (step S21). If the determination in step S21 is "NO", it is checked whether the flow signal I output from the flow sensor 17 is off (step S22).
[0048]
If it is confirmed that the flow signal I is off, a process of resetting the emergency operation flag set in the memory 20e is performed (step S23).
[0049]
On the other hand, if “YES”, that is, “P ≦ Po” is determined in the determination in step S21, a process of starting the submersible pump 13 is performed.
[0050]
Then, it is determined by the timer 20d whether the forced operation time t2 (> t1) has elapsed (step S25). Here, the forced operation time t2 is defined as being within the forced operation time t2 by prohibiting the input of the flow signal I output from the flow rate sensor 17 within the forced operation time t2 after starting the submersible pump 13. Of the submersible pump 13 is forcibly operated. Also, by setting the forced operation time t2 to be longer than the time t1, once the submersible pump 13 is forcibly stopped, the system is unstable, so the forced operation time is set to be longer. ing.
[0051]
If "YES" is determined in the determination in step S25, it is determined whether the flow signal I output from the flow sensor 17 is off (step S26).
[0052]
If "YES" is determined in this step S26, that is, if it is determined that the output of the flow rate sensor 17 is turned off, the emergency operation flag is reset, and the inverter detected by the output frequency detecting unit 20c is reset. The output frequency of 20b is read into the memory 20e as the output frequency when the amount of water is low (step S27).
[0053]
Then, the submersible pump 13 is stopped (Step S28).
[0054]
By the way, if the determination in step S26 is "NO", that is, if it is determined that the flow rate signal I is ON, the output frequency of the inverter 20b detected by the output frequency detection unit 20c is stored in the memory 20e in step S27 described above. It is determined whether or not the frequency is equal to or less than the low water volume output frequency read in (step S29).
[0055]
If “NO” is determined in the determination in step S29, the process returns to step S26 described above.
[0056]
On the other hand, when it is determined “YES” in the determination of step S29, the flow rate signal I is on, and the operation frequency of the inverter 20b is equal to or less than the output frequency at the time of low water flow for a predetermined time T3 (FIG. 6C). Reference) It is determined whether or not it has continued (step S30).
[0057]
If the determination in step S30 is "YES", a process for forcibly stopping the submersible pump 13 is performed (step S31).
[0058]
That is, the fact that the state in which the operating frequency of the inverter 20b is equal to or lower than the output frequency at the time of low water volume has continued for the predetermined time T3 does not mean that the flow signal I is turned on even when the submersible pump 13 is operating. Should be. However, when the flow signal I is on, it is determined that the flow sensor 17 is clogged with dust or the like and the on signal is erroneously output.
[0059]
Accordingly, in such a case, it is determined that the shutoff operation of the submersible pump 13 is being performed, and the submersible pump 13 is forcibly stopped.
[0060]
Next, a third embodiment of the present invention will be described with reference to the flowchart of FIG. The flowchart of FIG. 5 is obtained by replacing the process of step S9 in the flowchart of FIG. 2 with the process of step S10.
[0061]
Therefore, as shown in step S10, the display 21 indicates that the submersible pump 13 is abnormal, and the alarm 22 outputs an alarm, so that the operator can know the abnormality of the submersible pump 13 reliably. be able to. Further, the emergency operation flag is reset, and the forced operation time t2 is set.
[0065]
【The invention's effect】
According to the first aspect of the present invention, the detection output of the flow rate detection means is constantly monitored, and when the flow rate detection means is turned off, the emergency operation mode is released. Can do it.
[0066]
According to the second aspect of the invention, in the emergency operation mode, the forced operation time from when the submersible pump is started is automatically extended, so that the system can be operated stably.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a control device for a submersible pump common to each embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the first embodiment of the present invention.
FIG. 3 is a flowchart for explaining the operation of the second embodiment of the present invention.
FIG. 4 is a flowchart for explaining a start-up process of the present invention.
FIG. 5 is a flowchart for explaining the operation of the third embodiment of the present invention.
FIG. 6 is a timing chart for explaining the operation of each embodiment of the present invention.
[Explanation of symbols]
11 ... well,
13 ... submersible pump,
14 ... Piping,
15 ... check valve,
16 ... water supply piping,
17… Flow sensor,
18 ... Pressure tank,
19 ... pressure sensor,
20 ... Control unit,
20a CPU (central processing unit),
20b ... an inverter.

Claims (2)

A flow rate detecting means for detecting the flow rate discharged from the water pump, and a pressure detecting means for detecting the pressure of the water discharged from the water pump, controls the pressure of water discharged from the water pump to a constant pressure In the control device of the submersible pump to
Means for storing the operating frequency of the pump at the time when the flow rate detecting means normally changed from on to off during the operation of the submersible pump, as a low water volume output frequency,
Determining means for determining whether the operation frequency of the submersible pump is equal to or less than the low water volume output frequency for a predetermined time or more,
Pump stop means for stopping the pump to set the emergency operation mode when the operation frequency of the submersible pump is equal to or less than the small water volume output frequency for a predetermined time or more is determined by the determination means,
After stopping the submersible pump by the pump stopping means, determining means for determining whether the ON state of the flow rate detecting means has continued for a predetermined time or more,
When the determination means determines that the ON state of the flow rate detection means has continued for a predetermined time or more, the apparatus includes means for performing an abnormality display and a failure alarm,
Each time the pressure detecting means detects that the pressure is equal to or lower than the starting pressure, the submersible pump is started, and during a preset forced operation time, while performing an emergency operation of stopping the submersible pump after operation, In the emergency operation mode, the output of the flow rate detection means is constantly monitored, and when the flow rate detection means is turned off, the emergency operation mode is canceled. Above in emergency operation mode, the control device of the submersible pump according to claim 1, characterized in that the automatically extended from the forced operation time preset set value from the time of activating the water pump.

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