JP2003328979A - Water level control method for liquid tank and water level control device for liquid tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water level control device for a manhole tank which relatively easily copes with an abnormal rise of water level. <P>SOLUTION: When a water level L inside of the manhole tank 10 exceeds the predetermined middle water level L3 with a rise of water level, a first underwater pump P1 is operated. When the predetermined waiting time T1 passed after starting operation of the underwater pump P1 and the water level L inside of the manhole tank 10 is still higher than the middle water level L3, a second underwater pump P2 is operated. <P>COPYRIGHT: (C)2004,JPO

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 method and a water level control device for maintaining an appropriate water level in a liquid tank such as a sewage relay manhole tank.

[0002]

2. Description of the Related Art Conventionally, drainage devices for liquid tanks such as manhole tanks are provided with respective water level detecting means for detecting an upper limit water level, an intermediate water level and a lower limit water level. Then, when the intermediate water level is reached, the pump is operated to drain the water, and when the lower limit water level is reached, the operation of the pump is stopped.

Further, there is a drainage device provided with a plurality of pumps in preparation for abnormal water increase. For example, JP-A-54-3730
This is as disclosed in Japanese Patent Publication No.

In this drainage device, the operation of the first pump is started when the intermediate water level is reached. Then, when the upper limit water level is reached irrespective of the operation of the first pump due to abnormal water increase or the like, a plurality of pump devices are operated simultaneously.

[0005]

However, in the drainage facility as described above, the simultaneous operation of a plurality of pumps is started only when the upper limit water level is reached, so that it is difficult to cope with an abnormal increase in water in the waste water tank. Become.

Therefore, an object of the present invention is to provide a liquid tank water level control method and a liquid tank water level control device which can relatively easily deal with abnormal water increase.

[0007]

[Means for Solving the Problems] In order to solve the above problems,
The invention according to claim 1 is a water level control method for a liquid tank for draining a liquid flowing into a liquid tank to the outside to control the water level in the liquid tank, wherein the liquid level in the liquid tank is increased by increasing the water level. Discharging the liquid in the liquid tank with a first discharge amount when the water level exceeds an intermediate water level between the upper water level and the lower water level,
When the water level is still detected by the water level detection after the discharge of the liquid in the liquid tank is started at the first drainage amount, the liquid in the liquid tank is discharged at the second drainage amount larger than the first drainage amount. And a step of performing.

The invention according to claim 2 is a water level control method for a liquid tank for draining the liquid flowing into the liquid tank to the outside to control the water level in the liquid tank. When the water level in the liquid tank exceeds the intermediate water level between the upper limit water level and the lower limit water level, the step of discharging the liquid in the liquid tank at the first drainage amount, and the step of discharging the liquid in the liquid tank at the first drainage amount When the water level in the liquid tank is still higher than the intermediate water level after a preset waiting time has elapsed from the time when the liquid is started to be discharged, the second water amount in the liquid tank is larger than the first water amount. And the step of discharging the liquid.

According to a third aspect of the present invention, there is provided a water level control device for a liquid tank for controlling the water level in the liquid tank by draining the liquid flowing into the liquid tank to the outside. The drainage means for draining the liquid of No. 1 in a first drainage volume or a second drainage volume larger than the first drainage volume, a water level detection means for detecting the water level in the liquid tank, and a detection signal from the water level detection means. When it is determined that the water level in the liquid tank exceeds the intermediate water level between the upper limit water level and the lower limit water level due to the rise in the water level based on the above, the drainage so that the liquid in the liquid tank is discharged at the first discharge amount. After the standby time set in advance from the time when the means is operated to start discharging the liquid in the liquid tank with the first discharge amount, the water level in the liquid tank is changed based on the detection signal from the water level detecting means. It was judged that it was still above the intermediate water level. To come, in which and a discharge control means for operating said water discharge means to discharge the liquid in the liquid tank with the second amount of waste water.

As described in claim 4, the drainage means performs drainage by the first drainage amount or the second drainage amount by changing the number of operating pumps to change the drainage amount. It may be. Further, as described in claim 5, the drainage means may perform drainage at the first drainage amount or the second drainage amount by making the output of the pump variable by inverter control.

Further, according to a sixth aspect of the invention, the drainage control means determines, based on a detection signal from the water level detection means, that the water level in the liquid tank is below the lower limit water level. The draining operation by the draining means may be stopped after the pre-operation duration time preset according to the amount of drainage from the draining means has elapsed.

Further, as described in claim 7, when the water discharge control means determines that the water level in the liquid tank exceeds the upper limit water level based on the detection signal from the water level detection means, an alarm means is provided. It is good to give an alarm through.

Further, as described in claim 8, the water level detection means may include a float switch or a bubble type water level detection part, and more preferably, the water level is described in claim 9. The detection means may detect the intermediate water level and the lower limit water level by a bubble type water level detection unit, and detect the upper limit water level by a float switch.

According to the tenth aspect, the liquid tank may be a manhole tank buried underground.

Further, as described in claim 11, a drop recess is formed at the bottom of the liquid tank, and an underwater pump is provided in the liquid tank as the drainage means, and the submersible pump is also provided. The suction port of the suction pipe may be arranged in the drop recess.

Further, as in claim 12, the lower limit water level may be set at a position corresponding to the motor section of the submersible pump, and in the suction pipe of the submersible pump as claimed in claim 13. A minimum water level may be set at a position corresponding to the upper side of the suction port, and the preliminary operation duration may be set to a time at which the water level in the liquid tank reaches the minimum water level.

Further, as in claim 14, the liquid tank may have an inflow port on one side, and the intermediate water level may be set at a position corresponding to a lower position of the inflow port. 1
As described in 5, the liquid tank has an inlet on one side,
The upper limit water level may be set at a position corresponding to above the inflow port.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A water level control device for a liquid tank according to an embodiment of the present invention will be described below. In the present embodiment, a mode in which the present water level control device is applied to a manhole tank used for relaying sewage in a sewage transportation system that appropriately pumps sewage will be described.

This water level control device, as shown in FIG.
It is a device for draining the sewage flowing into the manhole tank 10 to the outside and controlling the water level L in the tank 10.

Here, the manhole tank 10 is provided with a bottom plate 12, a cylindrical manhole body portion 14 mounted and fixed on the bottom plate 12, and a manhole cover 16 for closing an upper opening of the manhole body portion 14. There is. The manhole tank 10 is buried in the ground in a state where the upper opening of the manhole body 14 is desired above the ground (when the manhole cover 16 is attached, the manhole cover 16 is exposed above the ground). .

A sewage inflow pipe 18 is connected to an intermediate portion in the vertical direction on one side of the manhole tank 10. Then, the sewage discharged from the sewage discharge source (such as each household) flows into the manhole tank 10 through the sewage inflow pipe 18 at irregular timings and amounts.

A sewage outflow pipe 20 is arranged above the other side of the manhole tank 10 so as to penetrate the manhole body 14. The sewage in the manhole tank 10 is discharged to the outside through the sewage outflow pipe 20 and pressure-fed to an external sewage treatment facility or the like by driving submersible pumps P1 and P2 described later.

Further, by disposing the inner tank 22 at the bottom of the manhole tank 10, two recessed depressions 23 (also referred to as a kettle) are formed at the bottom. Each of the depression recesses 23 is formed in a recessed shape into which a suction pipe 34 of a submersible pump P1, P2 described later can be inserted and arranged. When the water level L in the manhole tank 10 is lowered, sewage and foreign matter are dropped and flow into the recess 23.

In this manhole tank 10, the present water level control device includes a plurality of submersible pumps P1 as drainage means.
P2, the bubble type water level detecting unit 40 and the float switch 42 as the water level detecting means, and the bubble type water level detecting unit 4
0 and a drainage control unit 45 that controls the drive of the submersible pumps P1 and P2 based on detection signals from the float switch 42.
It has and.

The submersible pumps P1 and P2 have a motor unit 32.
And an impeller rotation accommodating portion 33 provided under the motor portion 32, and a suction pipe 34 vertically extending downward from the impeller rotation accommodating portion 33. And the motor unit 3
When the impeller (not shown) in the impeller rotation accommodating portion 33 is rotated by the drive of 2, the liquid is sucked through the suction pipe 34 and discharged to the outside from the discharge port (not shown). ing.

The submersible pumps P1 and P2 are installed and fixed to the bottom of the manhole tank 10 by a support tool such as an anchor bolt or a chain. In this installed and fixed state, the openings of the bell mouths 34a in the lower portions of the respective suction pipes 34 are arranged in the lower portions of the respective drop recesses 23. Then, the sewage and the foreign matter that have flowed into each of the drop recesses 23 are drained to an extremely low water level in a relatively short time.

Further, pressure feed pipes 36 are connected to the discharge ports of the submersible pumps P1 and P2, respectively. Each pressure pipe 3
6 is arranged so as to rise upward from the submersible pumps P1 and P2, and is connected to the sewage outflow pipe 20 from the check valve 37 through the sluice valve 38 and the bifurcated pipe 39. And the sewage pumped from each submersible pump P1, P2 is
It is configured such that the pressure pipes 36 flow into the bifurcated pipes 39 through the check valves 37 and the gate valves 38 to merge with each other, and are pressure-fed to the outside of the manhole tank 10 through the sewage outflow pipes 20. .

In this embodiment, two submersible pumps P are used.
1 and P2 constitute a drainage means for draining the sewage in the manhole tank 10 with the first drainage amount or the second drainage amount larger than the first drainage amount. That is, by driving either one of the submersible pumps P1 and P2 (driving the submersible pump P1 in the operation description below), the sewage is discharged with a relatively small first discharge amount. Also, both submersible pumps P
By driving 1 and P2, the sewage is discharged with a relatively large second discharge amount.

The drainage means may be composed of three or more submersible pumps. That is, by changing the number of operating a plurality of submersible pumps and changing the drainage amount, drainage may be performed with a relatively small first drainage amount or a relatively large second drainage amount.

Further, the drainage means may be constructed by changing the drainage capacity of a single submersible pump (for example, the rotation speed of the impeller). For example, by making the output of a single pump variable by inverter control,
Drainage can be performed by switching the amount of drainage.

Further, instead of the submersible pump, it is possible to use a pump in which a motor part or the like is installed outside the manhole tank 10 and only the suction pipe is introduced into the manhole tank 10.

The bubble type water level detector 40 is a component for detecting whether or not the water level is above (below or below) the lower limit water level L2 and the intermediate water level L3.
Reference numeral 2 is a constituent means for detecting whether or not the water level L exceeds (lowers) the upper limit water level L4.

That is, in this manhole tank 10, the lower limit water level L2 is the corresponding position of the motor part 32 of the submersible pumps P1 and P2 (the range between the upper end part and the lower end part of the motor part 32).
Is set to. Here, the lower limit water level L2 is not set at the lowermost portion of the manhole tank 10 (for example, near the bottom of the drop recess 23) is that the bubble-type water level detection unit 40 used as the water level detection unit or the pouring water level is used. Due to the characteristics of the detection part, if the sludge is clogged at the tip, the water level may be erroneously detected.
This is to avoid the effects of this accumulated sludge.

The intermediate water level L3 is located below the inlet of the wastewater inflow pipe 18 (the opening desired in the manhole tank 10) (between the lower part of the inlet and the upper limit water level, and slightly below the inlet). Is preferable). As will be described later, when the water level L exceeds the intermediate water level L3, the operation of the submersible pump P1 is started. Therefore, in the normal state, the water level in the manhole tank 10 is maintained in a range lower than the intermediate water level L3.

Furthermore, the upper limit water level L4 is located at a position corresponding to the upper side of the wastewater inlet (between the upper part of the wastewater inlet and the upper opening of the manhole tank 10, and preferably a position slightly higher than the inlet). It is set.

The lowest water level L1 is the submersible pump P1,
It is set at a position corresponding to the upper side of the suction port of the suction pipe 34 of P2 (between the suction port and the lower limit water level L2, preferably a position slightly higher than the suction port).

The bubble-type water level detector 40 constantly discharges a small amount of bubbles and detects the back pressure of the bubbles to detect the back pressure.
The water level in 0 is detected, and the water level is supported by a supporting means such as a chain below the lower limit water level L2 and near the upper portion of the depression 23. Then, it is detected whether the water level in the manhole tank 10 is higher than the lower limit water level L2 and whether the water level is higher than the intermediate water level L3, and the detection signal is sent to the drainage control unit 45. I'm giving. Instead of the bubble type water level detection unit 40, a throw-in type water level detection unit (for example, one that detects the water level by pressure detection by a semiconductor pressure sensor) may be used.

The float switch 42 turns on or off a built-in switch (a reed switch, a micro switch, etc.) by tilting the float body, and is placed at a position matched with the upper limit water level L4 by a supporting means such as a chain. It is supported. And manhole tank 1
When the water level in 0 rises and exceeds the upper limit water level L4, the float body tilts due to buoyancy to turn on or off the built-in switch, and a detection signal indicating that the water level exceeds the upper limit water level L4 is output.

The lower limit water level L2, the intermediate lower water level L3 and the upper limit water level L4 may be detected by the float switch (especially when the amount of dirt is small), or all of them may be detected by the bubble type water level detector. . Further, the means for detecting the water level is not limited to the float switch and the bubble-type water level detecting section, and an immersion type, an electrode type, and an ultrasonic type water level detecting device may be used.

The drainage control unit 45 includes a general microcomputer having a CPU, a ROM, a RAM and the like, and is in the form of a control panel having an operation panel and the like on the front surface.
It is arranged on the ground via a pillar. This drainage control unit 4
The power supply / signal cable 47 from 5 is the cable insertion tube 4
The manhole tank 10 is guided through the motor 8, and the motor part 32 of the submersible pumps P1 and P2 and the bubble type water level detecting part 4 are appropriately introduced.
0, connected to the float switch 42. And
The drainage control unit 45 controls the operation of the submersible pumps P1 and P2 through a drive circuit (not shown) based on the detection signals from the bubble type water level detection unit 40 and the float switch 42 according to a software program stored in advance.

Further, the water level control device is provided with an alarm means 46 composed of a sounding body such as a speaker and a warning light, and issues an alarm at a predetermined timing under the control of the drainage control section 45.

Next, regarding the operation of this drainage control device,
This will be described with reference to the flowcharts of FIGS. 2 and 3.

First, in the initial state, the submersible pump P
The operations of 1 and P2 are stopped. When the operation of the drainage control device starts from this state, first, in step S1, it is determined whether or not the water level L in the manhole tank 10 exceeds the lower limit water level L2, and if the water level L exceeds the lower limit water level L2, step S2 Proceed to. The water level L is the lower limit water level L
If it is the same as 2, it may be included in any of the judgment branches (similarly in the following judgment branches). And step S
2, the water level L in the manhole tank 10 is the intermediate water level L
It is determined whether the number exceeds 3.

When the water level L exceeds the intermediate water level L3, the process proceeds to step S3, the operation of the submersible pump P1 is started, and the manhole tank 10 is drained with a relatively small first drainage amount.

In step S4, the timer (not shown) starts counting from the time when the operation of the submersible pump P1 is started. When it is determined that the preset standby time T1 has elapsed in step S5, the process proceeds to step S6.

In step S6, the water level L is the intermediate water level L3.
It is determined whether or not If it is determined that the water level L is below the intermediate water level L3, the process proceeds to step S7. When it is determined in step S7 that the water level L is not below the lower limit water level L2, the process returns to step S6.

When it is determined in step S7 that the water level L has fallen below the lower limit water level L2, the operation proceeds to step S8, at which time counting by a timer (not shown) is started from the time when it is determined that the water level L falls below the lower limit water level L2. . And
If it is determined that the preset preliminary operation duration T2 set in advance has elapsed in step S9, the process proceeds to step S10. The duration T2 of the preliminary operation is the manhole tank 1
In the case where the manhole tank 10 is drained with a relatively small first drainage amount in a state where there is no inflow of sewage into 0,
It is the time that the water level L in the manhole tank 10 can be brought from the lower limit water level L2 to the lowest water level L1, and is a time that is calculated and speculatively determined in advance according to the capacity of the manhole tank 10 and the first discharge amount. Is.

Then, after the lapse of the preliminary operation duration T2,
In step S10, the operation of the submersible pump P1 is stopped,
A series of operations ends. In this state, manhole tank 1
The water level L within 0 is brought near the lowest water level L1.

On the other hand, if it is not determined in step S6 that the water level L is lower than the intermediate water level L3, that is, the water level L in the manhole tank 10 starts to decrease despite the start of operation of the submersible pump P1. If not (for example,
If the inflow of wastewater into the manhole tank 10 is abnormally large or if the submersible pump P1 is out of order), step S
11, the operation of the submersible pump P2 is started. In this state, since the two submersible pumps P1 and P2 are draining water, the wastewater in the manhole tank 10 is drained with a relatively large second drainage amount.

In step S12, the timer (not shown) starts counting from the time when the operation of the submersible pump P2 is started. When it is determined that the preset predetermined driving reexamination time T3 has elapsed in step S13, the process proceeds to step S14.

In step S14, it is determined whether the water level L in the manhole tank 10 is below the intermediate water level L3. Here, the water level L in the manhole tank 10 is the intermediate water level L
When it is determined that the water level L is lower than 3, the process proceeds to step S15, and it is determined whether or not the water level L is lower than the lower limit water level L2. If it is not determined that the water level L is below the lower limit water level L2, the process returns to step S14.

On the other hand, when it is determined in step S15 that the water level L is below the lower limit water level L2, step S1
In step 6, the time counting by a timer (not shown) is started from the time when it is determined that the water level L is below the lower limit water level L2. Then, the process proceeds to step S17, and if it is determined that the preset predetermined preliminary operation duration time T4 has elapsed from the time when it is determined that the water level L is below the lower limit water level L2, the process proceeds to step S18. The preliminary operation duration time T4 is the same as the preliminary operation duration time T2 when the manhole tank 10 is drained with the second discharge amount in a state where no dirty water flows into the manhole tank 10. 10
It is the time when the water level L in the tank is brought from the lower limit water level L2 to the lowest water level L1, and the capacity of the manhole tank 10 and the second
This is a time that is determined in advance by calculation and inference according to the amount of drainage.

After the preparatory operation duration T4 has elapsed, the operation of both submersible pumps P1 and P2 is stopped in step S18, and a series of operations is completed. In this state, the water level L in the manhole tank 10 is brought near the lowest water level L1.

On the other hand, in step S14, when it is not judged that the water level L in the manhole tank 10 is lower than the intermediate water level L3, that is, after the operation of both the submersible pumps P1 and P2 is started, a predetermined operation review time T3 has elapsed. However, if the water level L does not fall below the intermediate water level L3, the process proceeds to step S19.

In step S19, it is determined whether or not the water level L of the manhole tank 10 exceeds the upper limit water level L4.
If it is not determined that the water level L exceeds the upper limit water level L4, the process returns to step S14.

On the other hand, when it is determined in step S19 that the water level L exceeds the upper limit water level L4, step S2
The process proceeds to 0 and an alarm is issued through the alarm means 46.

Then, in step S21, it is determined whether the water level L is below the upper limit water level L4. When it is determined in step S21 that the water level L is not lower than the upper limit water level L4, the process returns to step S20 to continue the warning through the warning means 46, while step S21.
In, when it is determined that the water level L is below the upper limit water level L4, the process proceeds to step S22, the alarm is stopped, and the process returns to step S14.

When such an alarm is issued, a maintenance manager or the like of the manhole tank 10 appropriately inspects and manages the manhole tank 10 and the drainage control device.

Next, the water level L in the manhole tank 10, the operation timings of the submersible pumps P1 and P2, the timings of timings and the timings of alarms will be described with reference to the timing chart of FIG. In the figure, the state in which it is determined that the water level L in the manhole tank 10 exceeds the lower limit water level L2 is L2s is ON, and the state in which it is less than L2s is OFF. ing. Similarly, the state in which it is determined that the water level L exceeds the intermediate water level L3 and the upper limit water level L4 is indicated as ON for each of L3s and L4s, and the intermediate water level L3 and the upper water level L
L3s and L when it is judged that it is below 4
OFF is shown for each of the 4s.

First, at the time of inflow at a normal amount (at the time of normal inflow), the water level L gradually rises from the initial state, and when the water level L exceeds the intermediate water level L3, L3s is turned on and the submersible pump P1 is operated. Be started. As a result, the water level L starts to decrease. Then, after the lapse of the waiting time T1 from the time when the operation of the submersible pump P1 is started, the water level L becomes the intermediate water level L.
Below 3, and L3s is in the OFF state, operation of only the submersible pump P1 is continued.

When the water level L eventually falls below the lower limit water level L2, L2s is turned off. Water level L is lower limit water level L2
The time measurement is started from the time point where the temperature falls below the value of, and the operation of the submersible pump P1 is stopped when the predetermined preliminary operation duration time T2 has elapsed. As a result, the water level L is brought to the lowest water level L1 below the lower water level L2. Strictly speaking, when the inflow into the manhole tank 10 is continued, the water level L is slightly higher than the lowest water level L1.

At the time of inflow (when the water level increases) with a slightly larger amount,
The water level L gradually rises from the initial state, and the water level L is the intermediate water level L.
If it exceeds 3, L3s will be in the ON state and the submersible pump P
Operation 1 is started. Here, if the amount of inflow is slightly larger than the first amount of drainage by the submersible pump P1, the water level L still continues to rise. Then, since the water level L exceeds the intermediate water level L3 and the L3s is in the ON state after the lapse of the waiting time T1 from the time when the operation of the submersible pump P1 is started, the operation of the submersible pump P2 is started. The water level L starts to decrease due to the operation of both submersible pumps P1 and P2.

Timing is started from the start of the operation of the submersible pump P2, and after the elapse of a predetermined operation review time T3, the water level L
Goes below the intermediate water level L3, and L3s is turned off.
Further, the water level L continues to decrease and falls below the lower limit water level L2.
Timing is started from the time when the water level L falls below the lower limit water level L2, and the operation of the submersible pumps P1 and P2 is stopped when a predetermined preliminary operation duration T4 has elapsed. As a result, the water level L is brought to the lowest water level L1 below the lower water level L2. Strictly speaking, when the inflow into the manhole tank 10 is continued, the water level L is slightly higher than the lowest water level L1.

Even when the first drainage amount becomes 0 or becomes extremely small due to a failure of the submersible pump P1 or the like, the situation is the same as that at the time of increasing water.

At the time of inflow with an extremely large amount (at the time of abnormal water increase), the water level L gradually rises from the initial state, and when the water level L exceeds the intermediate water level L3, L3s is turned on and the submersible pump P1 is operated. Is started. Here, when the inflow amount is extremely large and is larger than the first drainage amount by the submersible pump P1, the water level L still continues to rise. Then, after the waiting time T1 has elapsed from the time when the operation of the submersible pump P1 was started, the water level L
Is above the intermediate water level L3 and L3s is in the ON state, so that the operation of the submersible pump P2 is started. Since the inflow amount is extremely large, the water level L continues to rise even when the operation of both the submersible pumps P1 and P2 is started.

When the water level L eventually exceeds the upper limit water level L4, L4s is turned on and an alarm is issued. After the alarm is issued, when the inflow amount decreases, the water level L decreases, the water level L falls below the upper limit water level L4, and L4s becomes the OFF state, the alarm is stopped. It should be noted that if an extremely large inflow continues and the water level L continues to rise (see the chain double-dashed line), the alarm is continued.

Even when the first drainage amount becomes 0 or becomes extremely small due to a failure of the submersible pump P1 or the like, the situation is the same as that at the time of this abnormal water increase.

Manhole tank 10 constructed as described above
According to the drainage control device of the manhole tank 1
If the water level L in the manhole tank 10 is still higher than the intermediate water level L3 after the preset waiting time T1 has elapsed from the time when the discharge of the sewage in 0 was started, the manhole will be discharged with the second discharge amount larger than the first discharge amount. To discharge the dirty water in the tank 10, compare the measures against the abnormal increase in water due to the extremely large inflow amount and the failure of the submersible pump P1 as the drainage means, etc. It can be done easily.

In particular, if the start of the operation of the second submersible pump P2 is notified to the outside through, for example, the alarm means 46, the operator (liquid tank manager) of this apparatus can quickly detect the (abnormal) water increase state. You can know Therefore, it is necessary to investigate environmental changes (reason for increased inflow of sewage and rainfall condition (weather)) near the manhole tank 10 and take further measures, or if it is left as it is, it will not reach the upper limit water level L4. The situation can be judged at an early stage. As a result, the subsequent actions can be performed with sufficient time.

In addition, even when the water level is slightly higher than usual,
When the state where the water level exceeds the intermediate water level L3 continues for the predetermined waiting time T1, the water is drained with a relatively large second drainage amount, so that the water level in the manhole tank 10 can be quickly brought to the lower limit water level L2 or less. Therefore, it is possible to prevent long-term retention near the intermediate water level L3, prevent spoilage water from spoiling and offensive odors, and maintain relatively good environmental protection in the vicinity of the manhole tank 10.

In the present embodiment, when the water level still exceeds the intermediate water level L3 after the elapse of a preset waiting time T1 from the time when the discharge of the sewage in the manhole tank 10 is started with the first discharge amount. , When discharging the sewage in the manhole tank 10 with the second discharge amount, but instead, the water level is still detected by the water level detection after the discharge of the sewage water in the manhole tank 10 with the first discharge amount is started. In addition, the sewage in the manhole tank 10 may be discharged with the second discharge amount. This uses a water level meter that can detect the water level in an analog manner (a water level meter that can continuously detect the water level in the manhole tank 10), and sequentially uses the current water level in the manhole tank 10 and the previous water level (before the predetermined period). The measured water level in the manhole tank 10) is compared, and when the water level of the latter is higher than the water level of the former, it is determined that the water level has increased, and the wastewater in the manhole tank 10 is discharged at the second discharge amount. It is realized by.

Further, after the water level L in the manhole tank 10 falls below the lower limit water level L2, the water level L in the manhole tank 10 is set to the lower limit water level L2 in order to stop the drainage operation by the submersible pumps P1 and P2 after the preparatory operation continues. Can be brought below.

Also, when the water level L in the manhole tank 10 exceeds the upper limit water level L4, an alarm is issued, so that the operator can know this.

Further, the members for detecting the intermediate water level L3 and the lower limit water level L2 are likely to be submerged in water. However, since these water levels L are detected by the bubble type water level detecting section 40, foreign matter or the like adheres to them. In addition to preventing malfunctions, the aeration effect of bubbles can be expected. Further, since the upper limit water level L4 is detected by the float switch 42, the cost can be reduced.

Further, the manhole basin 10 has a depression recess 23 formed at the bottom thereof, and the suction ports of the suction pipes 34 of the submersible pumps P1 and P2 are disposed in the depression recess 23. The sewage in the tank 10 can be discharged to a lower water level.

[0076]

As described above, according to the method for controlling the water level in the liquid tank according to claim 1 of the present invention, the water level is still increased by detecting the water level after the discharge of the liquid in the liquid tank is started at the first discharge amount. If it is found, the liquid in the liquid tank is discharged with the second discharge amount that is larger than the first discharge amount. Therefore, it is relatively easy to cope with the abnormal water increase by taking measures in the previous stage when the upper limit water level is not reached. be able to.

According to the liquid level control method of the liquid tank of the second aspect, the water level in the liquid tank is set after the preset waiting time has elapsed from the time when the discharge of the liquid in the liquid tank was started at the first discharge amount. If the water level is still above the intermediate water level, the liquid in the liquid tank is discharged with the second drainage volume that is larger than the first drainage volume. It can be done easily.

According to the liquid level control device of the liquid tank of the third to fifteenth aspects, after the preset standby time has elapsed from the time when the discharge of the liquid in the liquid tank with the first drainage amount is started,
When it is determined that the water level in the liquid tank is still higher than the intermediate water level based on the detection signal from the water level detecting means, the liquid in the liquid tank is discharged with the second drainage amount larger than the first drainage amount, It is possible to deal with abnormal water increase relatively easily by taking measures before the upper limit water level is reached.

According to the sixth aspect of the invention, after the water level in the liquid tank falls below the lower limit water level, the drainage operation by the drainage means is stopped after the duration of the preliminary operation. It can be brought below the lower water level.

According to the invention described in claim 7, an alarm is issued when the water level in the liquid tank exceeds the upper limit water level, so that the operator can know this.

According to the ninth aspect of the present invention, the member for detecting the intermediate water level and the lower limit water level is likely to be submerged in water. However, if these water levels are detected by the bubble type water level detection unit, foreign matter, etc. can be detected. In addition to preventing malfunction due to adhesion,
Aeration effect due to bubbles can be expected. Further, since the upper limit water level is detected by the float switch, the cost can be reduced.

According to the eleventh aspect of the present invention, a drop recess is formed in the bottom of the liquid tank, and the suction port of the suction pipe of the submersible pump as the drainage means is disposed in the drop recess. Therefore, the liquid in the liquid tank can be drained to a lower water level.

[Brief description of drawings]

1 is a partial cross-sectional schematic side view showing a water level control device for a manhole tank according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the above water level control device.

FIG. 3 is a flowchart showing the operation of the water level control device of the above.

FIG. 4 is a timing chart showing the relationship between the water level in the manhole tank and the operation timing of the submersible pump in the above water level control device.

[Explanation of symbols]

10 manhole tank 18 Sewage inflow pipe 20 Sewage outflow pipe 23 Drop recess 32 Motor part 34 Suction tube 40 Bubble type water level detector 42 float switch 45 Drainage control unit 46 Warning means P1, P2 submersible pump L water level L1 lowest water level L2 lower limit water level L3 intermediate water level L4 upper limit water level T1 waiting time T2 Preliminary operation duration T3 operation review time T4 Preliminary operation duration

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B65D 90/00 B65D 90/00 J 90/48 90/48 A E03F 5/22 E03F 5/22 (72) Inventor Hiroshi Hagio 1-1, Shinmeiwa-cho, Takarazuka-shi, Hyogo Shinmeiwa Kogyo Co., Ltd. Industrial Machinery Systems Division (72) Inventor Kouji Ueda 1-1, Shinmeiwa-cho, Takarazuka-shi, Hyogo Shinmeiwa Kogyo Co., Ltd. Industrial Machinery Systems Division F-term (reference) 2D063 DC06 3E070 AA13 AB02 CA03 CB01 CC07 GB04 GB06 RA01 RA09 VA30 3H020 AA03 BA07 CA07 DA01 DA22 EA04 EA07 EA14

Claims (15)

[Claims] 1. A water level control method for a liquid tank for draining a liquid flowing into a liquid tank to the outside to control the water level in the liquid tank, wherein the water level in the liquid tank is set to an upper limit when the water level rises. A step of discharging the liquid in the liquid tank with a first discharge amount when the intermediate water level between the water level and the lower limit water level is exceeded, and after starting discharge of the liquid in the liquid tank with the first discharge amount A method for controlling the water level in the liquid tank, comprising the step of discharging the liquid in the liquid tank with a second drainage amount larger than the first drainage amount when the water level is still detected by the water level detection. 2. A method for controlling a water level in a liquid tank by draining a liquid flowing into the liquid tank to the outside to control the water level in the liquid tank, wherein the water level in the liquid tank is an upper limit when the water level rises. A step of discharging the liquid in the liquid tank with a first discharge amount when the intermediate water level between the water level and the lower limit water level is exceeded, and from the time when the discharge of the liquid in the liquid tank with the first discharge amount is started Discharging the liquid in the liquid tank with a second discharge amount larger than the first discharge amount when the water level in the liquid tank is still higher than the intermediate water level after a preset standby time has elapsed, A method for controlling the water level in a liquid tank including the. 3. A water level control device for a liquid tank for draining the liquid flowing into the liquid tank to the outside to control the water level in the liquid tank, wherein the liquid in the liquid tank is a first drainage amount or the Drainage means for draining with a second drainage volume larger than the first drainage volume, water level detection means for detecting the water level of the liquid tank, and the liquid level rise based on a detection signal from the water level detection means When it is determined that the water level in the tank exceeds the intermediate water level between the upper limit water level and the lower limit water level, the draining means is operated to discharge the liquid in the liquid tank at the first drainage amount, and the first After the preset waiting time has elapsed from the time when the discharge of the liquid in the liquid tank was started with the amount of drainage, the water level in the liquid tank was still above the intermediate water level based on the detection signal from the water level detection means. When I judge that
A water level control device for a liquid tank, comprising: drainage control means for operating the drainage means to discharge the liquid in the liquid tank with the second amount of drainage. 4. The liquid level control device for a liquid tank according to claim 3, wherein the drainage unit changes the drainage amount by changing the number of operating pumps to change the first drainage amount or the second drainage amount. A water level control device for liquid tanks that discharges water according to the amount of water discharged. 5. The liquid level control device for a liquid tank according to claim 3, wherein the drainage unit varies the output of the pump by inverter control to drain the drainage at the first drainage amount or the second drainage amount. Liquid level control device for liquid tank. 6. The water level control device for a liquid tank according to claim 3, wherein the drainage control means is based on a detection signal from the water level detection means. The water level control device for the liquid tank, which stops the draining operation by the draining means after the preliminary operation continuous time preset according to the amount of drainage from the draining means has elapsed from the time when it is determined that the water level is below the lower limit water level. . 7. The liquid level control device for a liquid tank according to claim 3, wherein the drainage control means is provided in the liquid tank based on a detection signal from the water level detection means. A water level control device for a liquid tank, which issues an alarm through an alarm means when it is determined that the water level exceeds the upper limit water level. 8. The water level control device for a liquid tank according to claim 3, wherein the water level detecting means includes a float switch, a bubble type water level detecting section, or an immersion type water level detecting section. Including, the liquid level control device of the liquid tank. 9. The water level control device for a liquid tank according to claim 3, wherein the water level detection means sets the intermediate water level and the lower limit water level to a bubble type water level detection unit or a throw-in type. A water level control device for a liquid tank, the water level being detected by a water level detector and the upper limit water level being detected by a float switch. 10. The water level control device for a liquid tank according to any one of claims 3 to 9, wherein the liquid tank is a manhole tank buried underground. 11. The water level control device for a liquid tank according to claim 3, wherein a drop recess is formed in a bottom portion of the liquid tank, and the liquid serves as the draining means. A water level control device for a liquid tank, wherein a submersible pump is arranged in the tank, and a suction port of a suction pipe of the submersible pump is arranged in the drop recess. 12. The water level control device for a liquid tank according to claim 11, wherein the lower limit water level is set at a position corresponding to the motor section of the submersible pump. 13. The water level control device for a liquid tank according to claim 11 or 12, wherein a lower limit water level is set at a position corresponding to above the suction port of the suction pipe of the submersible pump, and the preliminary operation is continued. The time is set to such a time that the water level in the liquid tank is brought to the lowest water level, and the water level control device for the liquid tank. 14. The water level control device for a liquid tank according to claim 3, wherein the liquid tank has an inflow port on one side, and the intermediate water level corresponds to a lower side of the inflow port. The water level control device for the liquid tank, which is set to the position. 15. The water level control device for a liquid tank according to claim 3, wherein the liquid tank has an inflow port on one side, and the upper limit water level corresponds to above the inflow port. The water level control device for the liquid tank, which is set to the position.