JP2001193140A - Water level control device and water level control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the accumulation of scum on the wall face of a sewage tank. SOLUTION: A bubble level gage 10 is provided for detecting a water level of a sewage in a manhole 1. A fluctuation value P is at random changed each time when a submerged pump 3 is stopped. When the total value H'=H+P of a water level H set by the bubble level gage 10 and a fluctuation value P is equal to a detected water level (h), the submerged pump 3 is actuated to start draining. When the detected water level (h) is a preset lower limit water level H min or lower, the submerged pump 3 is stopped to finish draining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water level control device for controlling a water level in a sewage tank such as a manhole.

[0002]

2. Description of the Related Art Conventionally, a submersible pump has been installed in a sewage tank for temporarily storing sewage discharged from each household. It is discharged to the sewer pipes on the side to promote the distribution treatment of sewage. Then, as disclosed in, for example, JP-A-6-57811, in order to prevent sewage from overflowing from the sewage tank or to make the submersible pump run idle, the sewage tank is controlled according to the water level in the sewage tank. A water level control technique that controls the start and stop of a submersible pump (ON / OFF control) to maintain the water level of a sewage tank within a predetermined range is often used.

Conventionally, this type of water level control is performed by starting a submersible pump when the water level in a sewage tank rises to a certain upper limit position, and stopping the submersible pump when the water level falls to a predetermined lower limit position. Had been done.

[0004]

In such a water level control, the water level of the sewage once rises to the upper limit position by the inflow of the sewage, and then falls by the drainage operation of the submersible pump. By the way, since the scum floats near the water surface of the sewage, when the movement of the water surface changes from rising to falling, the scum tends to adhere to the inner wall of the sewage tank at the upper limit position. In the conventional water level control, since the submersible pump is always started at a fixed upper limit position, the scum adheres to a fixed position of the sewage tank. for that reason,
There is a problem that scum is piled up at a certain position, which promotes contamination of the sewage tank.

The present invention has been made in view of the foregoing, and an object of the present invention is to prevent the accumulation of scum and suppress the contamination of a sewage tank.

[0006]

In order to achieve the above object, according to the present invention, the upper limit water level of sewage, which is a reference for starting a submersible pump, is appropriately changed to disperse scum attachment positions.

Specifically, a water level control device according to the present invention is provided in a sewage tank into which sewage flows, and a submersible pump for discharging sewage from the sewage tank, and a water level for detecting the water level in the sewage tank. Detecting means for activating the submersible pump when the water level of the sewage tank is equal to or higher than a predetermined upper limit water level, and when the water level of the sewage tank is equal to or lower than the predetermined lower limit water level lower than the upper limit water level And an upper limit water level changing means for setting and changing the upper limit water level every time the submersible pump is started or stopped.

As a result, when the sewage flows into the sewage tank and the water level rises to the upper limit water level, the submersible pump is activated and the discharge of the sewage starts. As a result, the water level of the sewage drops, and overflow of the sewage from the sewage tank is prevented. On the other hand, when the water level of the sewage falls to the lower limit water level, the submersible pump stops. Thereby, a fixed amount of sewage is always secured in the sewage tank, and idle running of the submersible pump is prevented. Then, every time such a submersible pump is started or stopped, the upper limit water level serving as a reference for starting the submersible pump is changed. As a result, even if the scum contained in the sewage adheres to the inner wall of the sewage tank, the scum adheres to a different position every time the submersible pump is started or stopped, and the scum contained in the sewage does not accumulate at the same position on the inner wall. Absent. Therefore, accumulation of scum is prevented, and contamination of the sewage tank is suppressed.

It is preferable that the water level detecting means is constituted by a bubble type liquid level gauge.

[0010] Thus, air bubbles are supplied to the sewage in the sewage tank in accordance with the detection of the water level, so that the sewage is aerated and the generation of scum and odor is suppressed. Also, unlike the float type liquid level gauge, the bubble type liquid level meter has no moving parts,
It becomes easy to install even in a narrow place. In addition, since it is not affected by entanglement or sticking of foreign matter, water level control can be performed well even in a severe place where there are many foreign matters, oils and fats, and sludge.

[0011] In the water level control method according to the present invention, when the water level of the sewage tank becomes equal to or higher than a predetermined upper limit water level, the drainage of the sewage tank is started, and the water level becomes equal to or lower than a predetermined lower limit water level lower than the upper limit water level. A water level control method for keeping the water level of the sewage tank within a certain range by ending the discharge of sewage,
The upper limit water level is changed every time the discharge or start of the wastewater is started.

[0012] With this, the upper limit water level, which is the water level at which the movement of the water level of the sewage turns from rising to falling, is changed every time the discharge or discharge of the sewage is started, so that the scum contained in the sewage is reduced. The scum is prevented from sticking to the same position and the accumulation of scum is prevented. Therefore, contamination of the sewage tank is suppressed.

[0013]

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

As shown in FIG. 1, a water level control device according to an embodiment of the present invention controls a water level of a manhole 1 as a sewage tank. The manhole 1 is provided with an inflow pipe 2 and an outflow pipe 8, and sewage flows into the manhole 1 as appropriate through the inflow pipe 2. A submersible pump 3 for pumping sewage is installed inside the manhole 1. Suction bell mouth 4 of submersible pump 3
Are arranged in a recess 6 provided in the bottom wall 5 of the manhole 1. The discharge pipe 7 of the submersible pump 3 is
It is connected to the outflow pipe 8 of the manhole 1 so as to discharge the wastewater pumped up by the manhole 1 to the outside of the manhole 1.

In the present embodiment, a bubble level gauge 10 is provided as a water level detecting means for detecting the level of the sewage in the manhole 1. The bubble-type liquid level gauge 10 includes an air pump 12
And an air discharge unit 11 arranged to be immersed in sewage
And an air tube 14 that hermetically connects the air pump 12 and the air discharge unit 11, and a pressure sensor 13 that detects the air pressure of the air tube 14, and detects a water level of the sewage based on a detection value of the pressure sensor 13. It is configured to be.

The water level detecting means for detecting the water level of the sewage is not limited to the above-mentioned bubble type liquid level meter 10, but other types of water level detectors may be used. For example,
It is also possible to use a water level gauge or an ultrasonic water level meter.

The bubble type liquid level gauge 10 and the submersible pump 3 are connected to a controller 20 for executing a water level control described later. The controller 20 also serves as "start / stop control means" and "upper limit water level changing means" in the present invention.

In the water level control according to the present invention, the submersible pump 3 is started when the water level in the manhole 1 is higher than a predetermined upper limit water level Hmax, while the water level is lower than a predetermined lower limit water level Hmin.
When it becomes below, the operation of the submersible pump 3 is stopped. And
The upper limit water level Hmax is changed within a predetermined water level range every time the submersible pump 3 stops.

Although such control can be performed by appropriately changing the upper limit water level Hmax itself, in the present embodiment, in order to simplify the configuration of the controller 20 formed by the microcomputer, the control is substantially performed. The same control as described below is performed.

That is, in this embodiment, the controller 20 randomly sets the fluctuation value P every time the submersible pump 3 stops, and adds the water level H set by the bubble type liquid level meter 10 to the fluctuation value P. The submersible pump 3 is started based on whether or not the obtained value H ′ = H + P is equal to the detected water level h.

As shown in FIG. 2, the controller 20 comprises:
A fluctuation width input section 21 to which the fluctuation width Q (> 0) of the fluctuation value P is inputted and which stores the fluctuation width Q; -Q <P <
A fluctuation value setting unit 22 that randomly sets the fluctuation value P within the range of Q, a detection water level input unit 24 to which the detection water level h of the bubble type liquid level meter 10 is input, and a set water level H and the fluctuation value P A computing unit 25 for summing, a set water level input unit 23 to which the set water level H is input and storing the set water level H, a magnitude relationship between a sum H ′ of the set water level H and the fluctuation value P and the detected water level h And a comparator 26 for outputting a signal for starting the submersible pump 3 when the sum H ′ is equal to the detected water level H.

As shown in FIG. 3, in this water level control, first, in step ST1, while the submersible pump 3 is stopped, the fluctuation value P is automatically and randomly set within a range of -Q <P <Q. Is set. If the fluctuation width Q is too small, scum tends to accumulate at a fixed position. On the other hand, if the fluctuation width Q is too large, the water level, at which the submersible pump 3 starts, becomes too high, causing overflow of sewage. Conversely, there is a possibility that the water level serving as a reference for starting the submersible pump 3 becomes too low, and the number of times the submersible pump 3 starts up becomes too large. Therefore, in order to prevent scum from accumulating while preventing overflow of sewage and improving the operation efficiency of the submersible pump 3, it is preferable to appropriately set the value of the fluctuation width Q according to the volume of the manhole 1 and the like.

Next, in step ST2, the sum H 'of the set water level H and the fluctuation value P by the bubble type liquid level gauge 10 is obtained.
Is determined to be the same value as the detected water level h, and in the case of Yes, the process proceeds to step ST3 and the submersible pump 3 is started.
By the activation of the submersible pump 3, the wastewater in the manhole 1 is discharged to the outside, and the water level in the manhole 1 decreases.

Next, at step ST4, the detected water level h
Is less than or equal to a predetermined lower limit water level Hmin,
In the case of, the operation proceeds to step ST5, and the operation of the submersible pump 3 is stopped. Thereby, the pumping of the sewage is completed, and the sewage flowing from the outside is stored in the manhole 1.

Such water level control is repeatedly performed in accordance with inflow and discharge of sewage. Since the fluctuation value P is set to a different value each time in step ST1, the submersible pump 3 is started at a different water level each time. Will be.

Therefore, according to the present embodiment, since the activation of the submersible pump 3 is performed every time at a different water level, even if the scum floating on the water surface of the sewage adheres to the inner wall of the manhole 1, It does not adhere to, but adheres in a dispersed manner. Therefore, scum hardly accumulates on the inner wall of the manhole 1. As a result, since the scum adhered to the manhole 1 is reduced, an odor is less likely to be generated, and the number of times of cleaning can be reduced. Therefore,
The contamination of the manhole 1 by scum is suppressed, and the maintenance of the manhole 1 can be greatly improved.

[0027]

As described above, according to the present invention, the upper limit water level, which is the reference for starting the discharge of sewage, is changed every time the discharge of sewage starts or ends. It is possible to randomly change the position where the scum changes from ascending to descending, and it is possible to appropriately shift the position where the scum is attached to the wastewater tank. As a result, accumulation of scum in the sewage tank can be prevented, and contamination of the sewage tank can be suppressed.

If a bubble level gauge is used as the water level detecting means, the aeration of the sewage tank can be performed simultaneously with the detection of the water level of the sewage, and the contamination of the sewage tank can be further suppressed. In addition, since a movable portion is not required, it can be installed in a narrow place. Further, since there is no influence of entanglement or sticking of foreign matter, accurate water level control is possible even in a severe environment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a water level control device.

FIG. 2 is a block diagram of a part of a controller.

FIG. 3 is a flowchart of water level control.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Manhole 2 Inflow pipe 3 Submersible pump 4 Suction bellmouth 5 Bottom wall 6 Depression 7 Discharge pipe 8 Outflow pipe 10 Bubble level gauge (water level detecting means) 11 Air discharge section 12 Air pump 13 Pressure sensor 14 Air tube 20 Controller ( Start / stop control means, upper limit water level change means)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masami Ikeda 14 Takudai, Ono-shi, Hyogo F-term in Industrial Machinery Systems Division, Shin-Meiwa Industry Co., Ltd. 2D063 DC06 DC07 3H020 AA01 AA09 BA08 BA11 BA18 BA29 CA07 DA01 EA07 EA12

Claims (3)

[Claims] 1. A submersible pump installed in a sewage tank into which sewage flows, for discharging sewage in the sewage tank, water level detecting means for detecting a water level in the sewage tank, and a water level in the sewage tank is preset. Starting and stopping control means for activating the submersible pump when the water level becomes equal to or higher than the predetermined upper limit water level, and stopping the submersible pump when the water level in the sewage tank becomes equal to or lower than the predetermined lower limit water level lower than the upper limit water level; A water level control device, comprising: an upper limit water level changing means for setting and changing the upper limit water level every time the air conditioner is started or stopped. 2. The water level control device according to claim 1, wherein the water level detection means comprises a bubble type liquid level gauge. 3. When the water level of the sewage tank is equal to or higher than a predetermined upper limit water level, discharge of sewage of the sewage tank is started, and when the water level is equal to or lower than a predetermined lower limit water level lower than the upper limit water level, discharge of sewage water is terminated. A water level control method for maintaining the water level of the sewage tank within a certain range, wherein the upper limit water level is changed every time the discharge of sewage starts or ends.