JPH04124474A - Feed water device - Google Patents

Abstract

PURPOSE:To prevent the water fall and overloaded operation of a feed water device provided with more than two pumps by foreseeing the water fall of the pump due to the lowering of the operating current of a motor and switching the operation to the other pump. CONSTITUTION:When power is supplied to a microcomputer MCON, an operating lower limit current IS, and a power upper limit current IL are read and stored into a memory M. The signal of the contact PS of a pressure switch 8 is then read, an on-off judgment is made, and its result is stored into the memory M. Whether feed water pressure is lower than the starting pressure is then judged, and in the case of being lower than the starting pressure P1, the operation of a pump 4-1 is started. The operating current I of a motor is measured and compared with the operating lower limit current IS. In the case of I being less than IS, the clocking of its time (t) is started. In the case of (t) exceeding tL, current abnormality is judged, and abnormality frequency NS is counted. At the third time of NS, a pump 4 is regarded to be abnormal, and its operation is stopped. After informing this failure by an alarm lamp, change-over to the operation of a pump 4-2 is performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water supply system equipped with an electric pump and a pressure tank, and particularly to prevent waterless operation due to falling water, overload operation of the electric motor due to pump abnormality, or other causes. Install a water supply device suitable for the system to be prevented.

[Conventional technology]

BACKGROUND ART Waterless operation and overload of a pump have been detected based on the operating current of an electric motor.

An example of this type of device is Utility Model Application No. 52-98202. This device detects waterless operation when a low operating current continues for a certain period of time using an ammeter with a contact, and stops the motor.

[Problem to be solved by the invention]

The purpose of the above-mentioned conventional technology is to stop the electric motor when the user falls into the water, and no consideration is given to prevention of the fall itself or recovery from the fall.

The purpose of the present invention is to prevent water supply equipment having two or more pumps from falling into water and preventing overload operation.Furthermore, the present invention aims to make use of the operation of multiple pumps, a trial function, and external setting of abnormality detection conditions. The purpose is

(Means for solving the problem of fill) The above purpose is to provide two or more pumps, an electric motor to drive them, a pressure tank on the pump discharge side, a means for detecting the desired pressure or flow rate of the water supply system, In a water supply device having means (an alternator) for detecting the operating current of the electric motor, and a control device (microcomputer) capable of controlling, storing, and calculating according to a predetermined procedure, the operating current is monitored by the control device, This is achieved by switching the operation to another pump.For example, if the current is below a preset lower limit value (set in anticipation of a drop in load due to air in the pump) for a certain period of time (if water falls due to air (before the current occurs), or when a current of more than the preset operating current upper limit 1ai (determined from the rated current of the motor) continues for a certain period of time, or when a low current that is clearly thought to be falling into water continues. When a current or an abnormally high current is detected, the motor in question is stopped for a short time or instantaneously, and the pump is operated at rest.When the pump has its turn again due to alternating operation, it is operated normally. If the current abnormality appears again, the pump is switched to a paused state by the above-mentioned operation, and if the current abnormality of the same pump is repeated more than a certain number of times, it is assumed that the pump is abnormal, the operation of the pump is stopped, and a pump abnormality alarm is issued. , only other pumps will be operated.

[Effect]

The control device constantly monitors the operating current, and if the abnormal current continues for a certain period of time (if necessary, change the time depending on the rate of increase or decrease in current), it switches the pump and counts the number of times it stops due to X normal current. do. The pump operates repeatedly through alternating operation, but if it stops due to abnormal current a certain number of times in a row, it will be considered as a pump abnormality and the pump will stop operating, but if it stops due to abnormal current after a certain number of times, the pump will recover. and perform normal operation.

【Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. Figure 1, 211! I is a configuration diagram showing an embodiment of a water supply device for carrying out the present invention.

In Figure 1, PW is a power supply, MB is a molded circuit breaker, and C
T-1 and CT-2 are current transformers that detect the current flowing through the main circuit and transform it to an appropriate current value, MCIa and MC2a are magnetic contactors, MC-1 and MC-2 contacts, 4a-1 ,4a-
2 is a thermal relay that protects the electric motor from overload operation.
3-1.3-2 is an electric motor. RIS is a control power source taken from the secondary side of the molded circuit breaker MB, ss is a switch for switching between operation and stop, and T is a stabilization power supply that converts AC 200V alternating current into low voltage direct current (5V, 12V) and supplies it. The power supply unit), MCI, and MC2 are electromagnetic contactors. MC0
N is a microcomputer (hereinafter abbreviated as microcomputer), CPU is a central processing unit, M is a memory consisting of RAM and ROM, Z is a power supply connection terminal, Pro-1 to PIO
-3 is various input/output ports. In addition, DSI is an 8-bit dip switch that presets the pump motor's lower limit current 3, and PS2 is the pump motor's upper limit current 1.
．． This is a dip switch that allows you to preset the

l10-1 reads the operating current I of the motor 3 detected by the current transformer CT via the input/output water port P0-1 of the microcomputer MC0N, and also reads the operating current I of the motor 3 detected by the current transformer CT, and also reads the operating current I of the motor 3 detected by the current transformer CT through the input/output water port P0-1 of the microcomputer MC0N, and also reads the operating current I of the motor 3 detected by the current transformer CT.
The operating lower limit current I5 of the pump 3, which is preset by
Data such as upper limit current IL of operation are also input/output capo)P
This is an interface for reading via IO-1. PS is the pressure switch 8 or the flow rate switch 10 (second
The contact l10-2 in Figure) is an interface that reads the signal of contact PS from the input/output port PIO-2, l10-3
(input/output capo) Connect the magnetic contactor MC from Pro-3 to 0N-
This is an interface for OFF control. In Figure 2, 1 is a water tank, 2-1.2-2 is a water intake pipe, 3-1
．． 3-2 is an electric motor, 4-1.4-2 is a pump, 5-1.
5-2 is a gate valve, 6-1.6-2 is a check valve, 7 is a pressure tank with an air pocket inside, 8 is a pressure switch,
9 is a water supply pipe, IO is a flow rate switch, and 11 is a control circuit shown in FIG. FIG. 3 is a diagram showing the pump operation characteristics of the water supply system of this embodiment, where the vertical axis shows the pressure H and the horizontal axis shows the water IQ.
Take and show. In the figure, curve A represents the Q-H characteristic of the pump, curve C represents the load curve or current curve of the motor, P represents the starting pressure of the pump, and Q represents the amount of water pumped at that time. The pressure switch 8 in front is closed by Pyu, and the return pressure P-
It is set to open at 1. Further, Iol is the pump stop command current, rs is the lower limit current for operation set by the dip switch, and IL is the upper limit current for operation. FIG. 4 is a flowchart showing the operating procedure of the control device shown in FIG. 1 according to the embodiment of the present invention, and the operation of the water supply device will be explained in detail with reference to this drawing. In this embodiment, two pumps are used in a water supply system that operates alternately, and the allowable continuous time t of the lower limit current I5 is 30 seconds, and the lower limit current summer is 30 seconds. As an example, the allowable operating time tL is set to 60 seconds, and the allowable number of times the abnormal current is repeated is three times. In FIG. 1, when the molded circuit breaker MB is turned on and the switch SS is closed, power is supplied to the power terminal Z of the microcomputer MC0N via the stabilizing tff unit T. At this time, microcontroller M
In C0N, the initial setting of step 401 in FIG. 4 is executed. Next, in step 402, the dip switch DS
-1, operating lower limit current Is set in DS-2
, power supply upper limit current ■, interface I 10-1 ,
The data is read through the input/output capo Pro-1 and stored in the memory M. And contact P of pressure switch 8
S signal to interface l10-2, input/output water port P
It reads through IO-2, executes ON/OFF determination, and stores the result in memory M. Next, in step 403, it is determined whether the water supply pressure has reached the starting pressure or lower. As a result of the determination, if the starting pressure is less than or equal to P 0 to start operating the pump 4-1.
Next, in step 405, the operating current I of the motor is measured, and in the next step 406, the lower limit operating current 1. is proportional to. If ■ is less than Is due to air intrusion, etc., 501- in Figure 5
In step A, measurement of the time t during which the operating current I is equal to or lower than the operating lower limit current ls is started. Next 1502
- In step A, it is determined whether t exceeds the allowable time t. 503-A, 5 if t is 30 seconds or less
Current detection is performed again in step 04-A, and if the operating current ■ exceeds 1 s, it is regarded as recovery, and the 41st! I's 40
Proceed to step 7. If t exceeds tL, it is regarded as a current abnormality, and in step 505-A, the number of abnormalities NS is counted.IIN! The initial value of l is 0, and the pump 4-1
If a similar current abnormality is not observed during the next operation, the pump 4 is reset to 0. Next, in step 506-A, the number of abnormalities N is determined, and if Ns is the third time, the pump 4 is considered abnormal. , 507-A stops the operation of the pump 4-1, and after notifying the failure with a warning lamp at 508-A, the process proceeds to 402-2 and switches to operation of the pump 4-2. If ■≧15 at step 406 (normal state), the process advances to step 407 where the operating current I and the operating upper limit current 1. , make a comparison. If ■ shows a value of 15 or more, proceed to step 501-B in FIG.
The same operation as steps 01-A to 508-A is performed. 4
07 step ISl, 408 in case of (normal state)
Proceed to step and read the operating current ■ and pump stop command current ■.

2. Make a comparison.

As a result of the comparison, if x>r, . . . , the process returns to step 402 and repeats the operation. If I<1°F2, the pump 4-1 is stopped in step 409.

Then proceed to step 402-2, and do the same for pump 4.
- Perform operation 2. The control operation is repeated in accordance with the procedure described above, and water is supplied according to the amount of water demanded. In the embodiment described above, the upper and lower current limits of the pump can be set using dip switches, but these values may be stored in the memory M in advance as data, if necessary.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below. To predict water drop and switch the pump due to a drop in operating current due to air being mixed into the supplied liquid. Falling into the water can be prevented.

Also, by increasing the operating current, overload can be detected and the pump can be switched. Furthermore, by allowing the setting current to be set externally, it is possible to set pump switching conditions that suit the type of pump and motor, the installation status of the water supply device, and the usage status. In addition, in the process where multiple pumps are operated in a predetermined order, a - degree of current abnormality is not considered a defect, but only when a current abnormality is detected for the same pump or motor a certain number of times or more. By considering the above, it is possible to prevent the pump from stopping due to accidental or temporary factors. Furthermore, when a current abnormality occurs, by switching the pump and stopping the pump, it is possible to recover from the cause of the defect.

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram of a water supply device according to an embodiment of the present invention, No. 21! I is a system diagram of the water supply device of this embodiment, FIG. 3 is an operating characteristic diagram of the pump of this embodiment, and FIGS. 4 and 5 are flowcharts showing the control procedure of the control circuit of FIG. 2. 3-1.3-2...Electric motor, 4-14-2...Pump, 7...Pressure tank, 8...Pressure switch, 9.
... Water supply pipe, lO ... flow rate switch, CT ... current transformer (current detection means), MCI, MC2 ... electromagnetic switch, MC0N ... microcomputer, l10-1, l10-2.
...I/O boat diagram diagram l θ (water f)→

Claims (1)

[Claims] The system includes one or more pumps, an electric motor for driving the pumps, a pressure tank on the discharge side of the pump, a water supply pipe, and a pressure sensor provided therein; In a water supply system that operates the pumps according to a certain predetermined order based on fluctuations in the amount of water supplied, a drop in water from the pump is predicted by a decrease in the operating current of the electric motor, and the operation is switched to another pump. A water supply device characterized by: 2. In the water supply device according to claim 1, when the pump for which water fall was predicted has its turn to operate again, the operation is performed again, and when water fall is predicted a certain number of times in succession, the pump is determined to be defective. A water supply device characterized by being considered as. 3. The water supply system according to claim 1, wherein overload of the electric motor is sensed by an increase in operating current, and operation is switched to another pump. 4. In the water supply device according to claim 3, when the overloaded pump has its turn to operate again, the operation is performed again, and when overload is detected consecutively for a certain number of times or more, the pump is determined to be defective. A water supply device characterized by being considered as