JP3268488B2 - Water level control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level control device for controlling the level of sewage in a sewage tank within a predetermined range by a submersible pump disposed at the bottom of the sewage tank.

[0002]

2. Description of the Related Art Sewage in a sewage tank for temporarily storing sewage discharged from each household is usually controlled by a water level control device.
The sewage is controlled to be within a predetermined range to prevent sewage from overflowing from the sewage tank. The water level control device provided in the sewage tank has a submersible pump installed at the bottom of the sewage tank and a water level sensor for detecting the level of sewage in the sewage tank.

[0003] The water level sensor is turned on when the sewage reaches the operating water level which is the upper limit of the standard control water level,
The submersible pump is operated, and the wastewater in the wastewater tank is discharged. Then, when the water level of the sewage reaches the stop water level which is the lower limit of the preset standard control water level, the water level sensor is turned off, the drive of the submersible pump is stopped, and the discharge of the sewage in the sewage tank is stopped. You.

[0004] Japanese Patent Application Laid-Open No. 6-57811 discloses that
Water level control that provides a bubble type water level sensor that detects the water level based on the gas pressure fluctuation when gas is supplied into the sewage and generates bubbles, and controls the submersible pump based on the detection result of this water level sensor An apparatus is disclosed. In the water level control device disclosed in this publication, a float type water level upper limit sensor for detecting that the sewage in the sewage tank has reached the upper limit position immediately before overflowing is provided, and the sewage water level is set to the upper limit by the water level upper limit sensor. When the position is detected, the submersible pump is driven for a predetermined time. With such a configuration, if the submersible pump is not operating properly due to an abnormality in the water level sensor or the like, even though the sewage is at the predetermined operation water level, the water level of the sewage reaches the upper limit position, and the water level becomes higher. Since the sensor operates and the submersible pump is driven for a predetermined period of time, it is possible to reliably prevent the sewage from overflowing from the sewage tank.

[0005]

However, in such a water level control device, when the sewage in the sewage tank is discharged by driving the submersible pump, the sewage reaches a predetermined stop water level due to an abnormality in the water level sensor or the like. If the driving of the submersible pump is not stopped even though the submersible pump is turned off, the submersible pump may continue to be driven in an idling state in which the sewage cannot be sucked up. in this way,
When the submersible pump runs idle, there is a problem that the motor of the submersible pump becomes hot and the motor breaks down.

The present invention has been made to solve such a problem, and an object of the present invention is to continue driving of a submersible pump even though sewage in a sewage tank is at a predetermined low water level. Accordingly, it is an object of the present invention to provide a water level control device capable of reliably preventing the submersible pump from breaking down.

[0007]

According to the water level control device of the present invention, a water pump disposed in a sewage tank and a water level of the sewage in the sewage tank are controlled so as to discharge sewage in the sewage tank. A water level sensor for detecting that the water level is within the water level, a water level upper limit sensor for detecting that the level of the sewage in the sewage tank has reached a predetermined upper limit position, and a sewage tank based on the detection result of the water level sensor. A control unit that controls the submersible pump so as to maintain the water level of the sewage within a predetermined range, and drives the submersible pump for a predetermined time based on the detection result of the water level upper limit sensor, When the submersible pump is driven, the control unit detects that the submersible pump is being driven even when the water level of the sewage falls below a predetermined range, and stops driving the submersible pump. .

When the control unit detects that the submersible pump is being driven and stops driving the submersible pump even when the water level of the sewage falls below a predetermined range, the control unit performs control based on the water level sensor. Not to be.

The control unit detects that the submersible pump is driven even when the water level of the sewage falls below a predetermined range by detecting a decrease in the current supplied to the submersible pump.

The control unit detects that the submersible pump is being driven even when the water level of the sewage falls below a predetermined range by detecting that the submersible pump has been driven for a predetermined time or more.

The water level sensor is of a bubble type for detecting a water level based on a change in gas pressure when gas is supplied into the sewage to generate bubbles, a hydraulic type for detecting a water level based on a water pressure, and a sewage system. This is one of the ultrasonic wave types that transmit ultrasonic waves toward the water surface and detect the water level based on the ultrasonic waves reflected on the water surface.

The water level upper limit sensor is of a float type floating on the water surface.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an example of an embodiment of a water level control device of the present invention. The water level control device includes a submersible pump 11 installed at the bottom of a sewage tank 20 in which sewage flows in and stored, a pressure type water level sensor 12 installed at the bottom of the sewage tank 20, and a sewage tank 20. A float type upper limit water level sensor 13 for detecting the upper limit water level by floating on the surface of the stored sewage.

The submersible pump 11 installed at the bottom of the sewage tank 20 has a motor 11a arranged at the top and a pump casing 11b arranged below the motor 11a. , Motor 1
An impeller (not shown) that is driven to rotate by 1a is provided. When the impeller is rotated by the motor 11a, sewage in the sewage tank 20 is sucked into the pump casing 11b, and is discharged into a discharge pipe 11c provided perpendicular to the pump casing 11b. Discharge pipe 1
The sewage discharged into 1b is discharged outside the sewage tank 20.

The pressure type water level sensor 12 installed at the bottom of the sewage tank 20 has a bellows type pressure receiving surface for receiving the water pressure of the sewage in the sewage tank 20, and the pressure receiving surface corresponds to the water level. Is changing. Water level sensor 1
2 is that the sewage in the sewage tank 20 reaches the upper limit operation water level in a predetermined range set in advance, and the pressure receiving surface shifts by a predetermined amount to be turned on, and the water level of the sewage drops. Then, the stop water level becomes the lower limit side of the predetermined range, and the pressure receiving surface shifts by a predetermined amount to be turned off.

In the float type water level upper limit sensor 13, the sewage flowing into the sewage tank 20 is higher than the upper limit water level at which the water level sensor 12 is turned on, and the sewage overflows from the sewage tank 20. When it reaches the immediately preceding upper limit position, it floats on the wastewater and turns on.

The motor 11a of the submersible pump 11 is controlled by a control unit 14 provided above the sewage tank 20. The control unit 14 includes an output of the water level sensor 12 and a water level upper limit sensor 13 Output is given.

FIG. 2 is a control circuit diagram in the control unit 14 provided above the sewage tank 20. The motor 11 a of the submersible pump 11 is provided with a three-phase AC power supply,
And the normally open contact 32a of the electromagnetic relay. The AC power supply is connected to a control changeover switch 33 that is operated to switch the level of the sewage in the sewage tank 20 between automatic control and manual control. This control changeover switch 33 is connected to a manually-connected normally open contact 33 connected in parallel.
a and a normally closed contact 33b on the automatic side, and the exciting coil 32 of the electromagnetic relay is connected in series to the normally opened contact 33a on the manual side. When the exciting coil 32 is excited, the normally open contact 32 provided between the AC power supply and the motor 11a of the submersible pump 11 is turned on.

The normally open contact 3b of the pair of electromagnetic relays is connected to the normally closed contact 33b on the automatic side of the control changeover switch 33.
The parallel circuits 4a and 35a are connected. A normally closed contact 36a is connected to the parallel circuit of each normally open contact 34a and 35a.
b are connected in series, and the excitation coil 32 is connected in series to the normally closed contact 36b.

A normally closed contact 36b interposed between a parallel circuit of the normally open contacts 34a and 35a and the exciting coil 32
Is operated by an exciting coil 36 which is excited by an output of a current detection circuit 43 for detecting a current flowing from the AC power supply to the motor 11a of the submersible pump 11, and the current detected by the current detection circuit 43 When the value falls below a predetermined value, the switch circuit 43a connected in series with the exciting coil 36 is turned on, the exciting coil 36 is excited, and the normally closed contact 36b is turned off. The current detection circuit 43 is provided with the motor 1 of the submersible pump 11.
When the supply current to 1a is less than half of the rated current, the switch circuit 43a is turned on to excite the excitation coil 36.

The AC power supply is further connected to a normally open contact 37a which is turned on by a timer 37. The normally open contact 37a has a normally closed contact 38b operated by an exciting coil 38 of an electromagnetic relay and an alarm lamp. 39 are connected in series. The normally open contact 3 of the timer 37
A parallel circuit of a normally open alarm release switch 41 for releasing the lighting of the alarm lamp 39 and a normally open contact 38a operated by the exciting coil 38 is connected to the parallel circuit 7a. The excitation coil 38 is connected in series.

The voltage of the AC power supply is transformed by a transformer 42 and supplied to an exciting coil 34 of an electromagnetic relay via a water level sensor 12 and reset by a timer 37 via a water level upper limit sensor 13. Through a normally closed contact 37b for the electromagnetic relay. The voltage transformed by the transformer 42 is further supplied to the exciting coil 3 of the electromagnetic relay.
5 is also provided to a timer 37 via a normally open contact 35c.

The operation of the water level control device having such a configuration is as follows. The water level control device is normally in an automatic control state in which the normally closed contact 33b on the automatic side in the control changeover switch 33 is turned on. In such a state, the sewage tank 2
When the sewage flows into 0 and the sewage reaches the operating water level on the upper limit side of a predetermined range set in advance, the water level sensor 12 is turned on. Thereby, the exciting coil 34 of the electromagnetic relay
Is excited, and the normally-closed contact 33b of the control changeover switch 33
The normally open contact 34a connected in series with the power supply is turned on, and the exciting coil 32 is excited. When the exciting coil 32 is excited, the normally open contact 32a provided between the AC power supply and the motor 11a of the submersible pump 11 is turned on, and the motor 11a is driven.

When the motor 11a of the submersible pump 11 is driven, the sewage in the sewage tank 20 is discharged to the outside of the sewage tank 20 through the discharge pipe 11c, and the level of the sewage in the sewage tank 20 decreases. Then, when the water level of the sewage becomes equal to or lower than the stop water level on the lower side of the predetermined range set in advance, the water level sensor 12 is turned off, and the exciting coil 32 is demagnetized.
The normally open contact 34a is turned off. As a result, the excitation coil 32 is demagnetized, the normally open contact between the AC power supply and the motor 11a is turned off, the motor 11a of the submersible pump 11 is stopped, and the discharge of the sewage from the sewage tank 20 is completed. I do.

As described above, the motor 11a of the submersible pump 11 is controlled based on the water level of the sewage in the sewage tank 20, so that the sewage in the sewage tank 20 does not overflow from the sewage tank 20 and the water level is increased. It is controlled within a predetermined range.

In such water level control, if an abnormality occurs in the water level sensor 12, the submersible pump 11 is driven, so that the sewage tank 20 is discharged even though the sewage is discharged from the sewage tank 20. The water level sensor 12 may not be in the off state even if the water level of the sewage in the inside falls below the stop water level on the lower limit side of the preset predetermined range. In this case, since the water level sensor 12 continues to be in the ON state, the exciting coil 32 is not demagnetized. Therefore, the driving of the motor 11a in the submersible pump 11 is not stopped, and the drainage of the wastewater from the wastewater tank 20 is performed. Will be continued.

As described above, when the drainage of the sewage is continued by the submersible pump 11, the amount of the sewage in the sewage tank 20 decreases, and the submersible pump 11 cannot suction the sewage. As a result, the load on the motor 11a in the submersible pump 11 decreases, and the supply current to the motor 11a decreases. At this time, the current detection circuit 43 detects the supply current to the motor 11a,
When the value of the supply current to a becomes equal to or less than half of the rated current value, the current detection circuit 43 turns on the switch circuit 43a to excite the excitation coil. Thereby, the normally closed contact 36
b is turned off, the exciting coil 32 is demagnetized, the normally open contact 32a between the AC power supply and the motor 11a is turned off, and the driving of the motor 11a is stopped.

As described above, when the water level sensor 12 becomes abnormal and the sewage in the sewage tank 20 is continuously discharged, the submersible pump 11 becomes idle, and the idle state is detected by the current detection circuit 43. Being a motor 1
Since the driving of the motor 1a is stopped, the temperature of the motor 11a does not become high, and the failure of the motor 11a can be prevented.

Further, in such a water level control, even if an abnormality occurs in the water level sensor 12 and the sewage in the sewage tank 20 becomes higher than the operating water level on the upper limit side in a predetermined range, the water level sensor 12 is not turned on. In this case, when the sewage in the sewage tank 20 reaches the upper limit water level immediately before overflow, the water level upper limit sensor 13 is turned on. As a result, the exciting coil 35 is excited, the normally open contact 35a is turned on, and the exciting coil 32 is excited. As a result, the normally open contact 32a between the AC power supply and the motor 11a is turned on, the motor 11a is driven, and the wastewater in the wastewater tank 20 is discharged. Therefore, even if an abnormality occurs in the water level sensor 12, there is no possibility that the sewage overflows from the sewage tank 20.

When the water level upper limit sensor 13 is turned on, the normally open contact 35c is turned on.
The timer 37 is operated. Thereby, the normally open contact 37
a is turned on, and the alarm lamp 39 is turned on.

When a predetermined time set by the timer 37 has elapsed, the normally closed contact 37b is turned off, and the exciting coil 35 is demagnetized. Thereby, the normally open contact 35a
Is turned off, and the exciting coil 32 is demagnetized. As a result, the normally open contact 32a provided between the AC power supply and the motor 11a of the submersible pump 11 is turned off, and the driving of the submersible pump 11 is stopped. Also, the excitation coil 35
, The normally open contact 35c is also turned off, and the timer 37 is reset.

Further, when the alarm cancel switch 41 is turned on while the alarm lamp 39 is lit by turning the water level upper limit sensor 13 on, the exciting coil 38 is excited, and the exciting coil 38 is turned off. The normally open contact 38a for self-holding is turned on and the normally closed contact 3
8b is turned off. Thereby, the warning lamp 39 is turned off.

In the above embodiment, when the submersible pump 11 is driven based on the detection result of the water level sensor 12, the submersible pump 11 is driven even if the water level of the sewage falls below a predetermined range. Is detected based on the supply current to the motor 11a of the submersible pump 11, but the water level of the sewage falls below a predetermined range based on the fact that the submersible pump 11 has been driven for a predetermined time or more. May be detected.

FIG. 3 shows a control circuit diagram in the control unit 14 in this case. The control circuit includes a timer 4 for measuring a time during which the drive motor 11 of the submersible pump 11 is driven.
4 is connected in series with the normally open contact 32c. The normally open contact 32c is turned on when the exciting coil 32 of the electromagnetic relay that turns on the normally open contact 32a between the AC power supply and the motor 11a is turned on, and the timer 44 turns on the drive motor 11a. The driving time is measured. When the predetermined time set by the timer 44 elapses, the water level upper limit sensor 13
The normally-open contact 44a connected in parallel with is turned on. An excitation coil 45 of an electromagnetic relay is connected in series to the normally open contact 44a via a normally open reset switch 46 which is turned on by a timer 37 connected in series with the water level upper limit sensor 13. When the exciting coil 45 is excited, the normally closed contact 45b provided between the water level sensor 12 and the exciting coil 34 is turned off, and the control by the water level sensor 12 is not performed. When the exciting coil 45 is excited, the normally open contact 4 a for self-holding connected in parallel with the normally open contact 44 a connected in series via the reset switch 46.
5a is turned on, and the exciting coil 45a is held by itself.

In the water level control device having such a control circuit, when the water level sensor 12 is turned on and the excitation coil 34 is excited to excite the excitation coil 32, the water level sensor 12 is provided on the power supply line of the motor 11a. The normally-open contact 32a is turned on and the other normally-open contacts 32 are turned on.
c is also turned on, and the timer 44 is operated. As a result, the motor 11a is driven and the submersible pump 11
Thereby, the water in the sewage tank 20 is discharged. When the motor 11a continues to be driven for a predetermined time set by the timer 44, for example, 30 minutes, the normally open contact 44a is turned on by the timer 44 and the exciting coil 45 is excited. Thereby, the exciting coil 34
The normally closed contact 45b located between the water level sensor 12 and the water level sensor 12 is turned off,
Is not implemented, and therefore the water level sensor 12
Is turned on, the excitation coil 34 and the excitation coil 32 are not excited, so that the motor 11a is not driven.

In such a state, when sewage is stored in the sewage tank 20 and the water level upper limit sensor 13 is turned on, the exciting coil 35 is excited and the normally open contact 35a is turned on. The exciting coil 32 is excited. As a result, the normally open contact 32a is turned on, and the motor 11a is driven. In this case, when the water level upper limit sensor 13 is turned on, the timer 37 is operated. After a predetermined time has elapsed, the normally closed contact 37b connected in series with the exciting coil 35 is turned off, and the exciting coil 35 is demagnetized. At the same time, the exciting coil 32 is also demagnetized, and the normally open contact 32a is turned off.
The driving of a is stopped. Thereafter, only when the water level upper limit sensor 13 is turned on, the motor 11a is driven and the sewage is discharged from the sewage tank 20.

When normal control by the water level sensor 12 is performed after the abnormality of the water level sensor 12 is eliminated,
The reset switch 46 is operated to be turned off.
As a result, the normally closed contact 45b provided between the water level sensor 12 and the exciting coil 34 is turned on.
The state is reset to a state where the control of the drive motor 11a based on the water level sensor 12 is possible.

In the above embodiment, the water level sensor 12 detects the water level based on the water pressure of the sewage in the sewage tank 20. However, the present invention is not limited to such a configuration. A bubble-type water level sensor that detects the level of sewage in the sewage tank 20 based on gas pressure fluctuations when gas is supplied to generate bubbles in sewage, or an ultrasonic wave is applied to the water surface from above the sewage water surface. It may be configured to use an ultrasonic type water level sensor that emits light toward the water surface and detects the water level based on the ultrasonic wave reflected on the water surface. In the case of a bubble type water level sensor, an air pump for supplying gas into the wastewater is required.

[0040]

As described above, the water level control device of the present invention
When controlling the submersible pump based on the water level sensor to maintain the water level of the sewage within a predetermined range, if the submersible pump is driven even if the water level of the sewage falls below the predetermined range, the submersible pump is driven. Since the pump is stopped, there is no possibility that the motor of the submersible pump becomes hot and breaks down, and the submersible pump can be stably used for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an embodiment of a water level control device of the present invention.

FIG. 2 is a circuit diagram showing an example of a control circuit used in the water level control device.

FIG. 3 is a circuit diagram showing another example of a control circuit used in the water level control device.

[Explanation of symbols]

 Reference Signs List 11 submersible pump 11a motor 11b pump casing 12 water level sensor 13 water level upper limit sensor 20 sewage tank

Claims (6)

(57) [Claims] Claims: 1. To discharge sewage in a sewage tank,
A submersible pump located in the sewage tank, a water level sensor that detects that the level of sewage in the sewage tank is within a predetermined range, and that the water level of the sewage in the sewage tank has reached a predetermined upper limit position Based on the detection result of the water level sensor, based on the detection result of the water level sensor, while controlling the submersible pump to maintain the water level of the sewage in the sewage tank within a predetermined range, the detection result of the water level upper limit sensor A control unit adapted to drive the submersible pump for a predetermined time based on the control unit, wherein the control unit operates the submersible pump even when the level of the sewage falls below a predetermined range when the submersible pump is driven. A water level control device, wherein the water level control device detects that the operation is being performed and stops driving the submersible pump. 2. The control unit according to claim 1, wherein the control unit detects the driving of the submersible pump and stops driving the submersible pump even when the water level of the sewage falls below a predetermined range. The water level control device according to claim 1, wherein the water level control device is not implemented. 3. The water level control device according to claim 1, wherein the control unit detects that the submersible pump is driven even when the water level of the sewage falls below a predetermined range, by a decrease in the current supplied to the submersible pump. . 4. The control unit detects that the submersible pump is driven even when the water level of the sewage falls below a predetermined range, by driving the submersible pump for a predetermined time or more. A water level control device according to item 1. 5. The water level sensor detects a water level based on a change in gas pressure when supplying gas into the wastewater to generate bubbles, a water pressure type detecting a water level based on water pressure, The water level control device according to claim 1, wherein the water level control device is one of an ultrasonic type that transmits an ultrasonic wave toward a water surface of the sewage and detects a water level based on the ultrasonic wave reflected on the water surface. 6. The water level control device according to claim 1, wherein the water level upper limit sensor is of a float type floating on the water surface.