Drainage pit and drainage method

Abstract

To provide a drain pit capable of automatically discharging accumulated water further reliably.SOLUTION: A drain pit 1 has an electrode type water level gauge 40 that detects a water level based on the energization state of an electrode that contacts water and energizes, a float type water level gauge 41 that detects a water level based on the movement of a float accompanying the water level of a liquid surface, and a drainage section 3 that can drain water to the outside. The operation of the drainage section 3 is controlled based on at least one of a detection signal of the electrode type water level gauge 40 and a detection signal of the float type water level gauge 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drainage pit and a drainage method. [Background technology]

[0002] Conventionally, there is known a technology for detecting the water level of water accumulating in a pit and automatically draining the water. For example, Patent Document 1 describes an automatic drainage device in which a pit drain tank with a level sensor is installed in a pit at the bottom of an elevator shaft that drains water from an air conditioner installed in the elevator car, and the device starts and stops a drainage pump based on the output signal of the sensor to automatically drain the water from the tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-105350 Summary of the Invention [Problem to be solved by the invention]

[0004] In drainage pits that collect and drain rainwater and other water from within a site, electrode-type water level gauges are used for detection, rather than float-type water level gauges, which may become unable to detect water levels due to the presence of floating particles in the drainage water. However, when a large amount of pure water is poured onto the site during a firefighting drill or other such event, water with low conductivity flows into the drainage pit, and there is a risk that the electrode-type water level gauge will not be able to detect the water level.

[0005] Therefore, an object of the present invention is to provide a drainage pit that can automatically drain accumulated water more reliably. [Means for solving the problem]

[0006] (1) The drainage pit according to the present invention comprises an electrode-type water level gauge that detects the water level based on the state of conduction of an electrode that is in contact with the liquid and conducts electricity, a float-type water level gauge that detects the water level based on the movement of a float that corresponds to the level of the liquid surface, and a drainage device that can drain the liquid to the outside, and controls the operation of the drainage device based on at least one of the detection signals of the electrode-type water level gauge and the float-type water level gauge.

[0007] (2) The water level detection position of the electrode-type water level meter is located lower than the water level detection position of the float-type water level meter.

[0008] (3) In the drainage pit according to the present invention, the electrode-type water level meter is capable of detecting a first lower limit water level and a first upper limit water level that is set at a position higher than the first lower limit water level, and the float-type water level meter is capable of detecting a second lower limit water level and a second upper limit water level that is set at a position higher than the second lower limit water level, and operates the drainage device when the first upper limit water level or the second upper limit water level is detected, and stops operation of the drainage device when the first lower limit water level or the second lower limit water level is detected.

[0009] (4) In the drainage pit according to the present invention, a groove is formed in the bottom, and the electrode-type water level gauge, the float-type water level gauge, and the drainage device are provided in the groove. [Effects of the Invention]

[0010] According to the present invention, a drainage pit can be provided that can automatically drain accumulated water more reliably. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an example of a drainage system provided on the site of a power plant according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a cross-sectional view of the water level detection unit and its surroundings according to the embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram for explaining an example of a water level detection unit according to an embodiment of the present invention. [Figure 4] 1 is a flowchart illustrating an example of a flow of wastewater treatment according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of a drainage system S installed within the grounds of a power plant according to an embodiment of the present invention will be described below with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing an example of a drainage system S installed within the grounds of a power plant G according to an embodiment of the present invention. Figure 2 is a cross-sectional view of the area around a water level detection unit 4 according to an embodiment of the present invention. The drainage system S has, for example, a transformer facility 2 installed within the grounds of the power plant G, and a drainage pit 1 installed adjacent to the transformer facility 2.

[0013] The drainage pit 1 is a concave-shaped structure made of concrete on the power plant site G. In the example of Figure 1, the drainage pit 1 is provided adjacent to the transformer equipment 2. However, the location where the drainage pit 1 is provided is not limited to this.

[0014] In addition, the drainage pit 1 is provided with a water level detection unit installation groove 10 formed in the concave bottom for installing the water level detection unit 4 described later, as shown in Figure 2, the water level detection unit 4 installed in the water level detection unit installation groove 10, a drainage unit 3 that drains water from the drainage pit 1 based on the detection results of the water level detection unit 4, and a control circuit 50 that includes a terminal block for connection to the water level detection unit 4 and a circuit for water level control.

[0015] Next, the water level detection unit 4 will be described with reference to Figures 2 and 3. Figure 3 is a schematic diagram for explaining an example of the water level detection unit 4 according to one embodiment of the present invention. The water level detection unit 4 has an electrode-type water level gauge 40 and a float-type water level gauge 41.

[0016] The electrode-type water level gauge 40 is a water level gauge that detects the water level based on the conduction state of two or more electrodes in contact with a conductive liquid. In this embodiment, the electrode-type water level gauge 40 has four electrodes, a common electrode 401, an L1 water level detection electrode 402, an H1 water level detection electrode 403, and an HH water level detection electrode 404, as shown in Fig. 3, and a base 400 to which one end of each of the four electrodes is fixed.

[0017] The common electrode 401 is a common earth electrode connected to the other three electrodes, and the length of the common electrode 401 is set to be the longest among the four electrodes. The lengths of the other three electrodes are set to be shortest in the order of the L1 water level detection electrode 402, the H1 water level detection electrode 403, and the HH water level detection electrode 404. Therefore, the lower ends of the four electrodes are located higher in this order, as shown in FIG. 3 : common electrode 401, L1 water level detection electrode 402, H1 water level detection electrode 403, and HH water level detection electrode 404. The electrode-type water level gauge 40 detects the water level based on the conduction state of the electrodes when the common electrode 401 and at least one other electrode come into contact with liquid water.

[0018] The number of electrodes of the electrode type water level gauge 40 is not limited to the above example, and may be three, five or more. The electrode type water level gauge 40 may have more than one earth electrode instead of one. The electrode type water level gauge 40 is provided on approximately the bottom surface of the water level detection unit installation groove 10 so as to protrude above the water level detection unit installation groove 10.

[0019] As shown in Fig. 2, the electrode-type water level gauge 40 can detect a first lower limit water level L1, which is set at the same height as the drainage pump 30, and a first upper limit water level H1, which is set above the first lower limit water level L1. Specifically, in the electrode-type water level gauge 40, the first lower limit water level L1 is detected when the common electrode 401 and the L1 water level detection electrode 402 come into contact with water. In addition, in the electrode-type water level gauge 40, the first upper limit water level H1 is detected when the common electrode 401 and the H1 water level detection electrode 403 come into contact with water. In addition, in the electrode-type water level gauge 40, the HH water level shown in Figs. 2 and 3 is detected when the common electrode 401 and the HH water level detection electrode 404 come into contact with water. In this embodiment, the HH water level detection electrode 404 is used for a full water warning.

[0020] The float-type water level gauge 41 is a water level gauge that has a float that moves up and down and detects the water level based on the movement of the float according to the water level of the liquid. In this embodiment, as shown in Fig. 3, the float-type water level gauge 41 has a microswitch 410 that switches ON / OFF with a predetermined force, a rod 411 connected to a shaft (not shown) inside the microswitch 410, a float 412 through which the rod 411 is slidably inserted, and an upper limit stopper 413 and a lower limit stopper 414 that can be fixed onto the shaft.

[0021] In the float-type water level indicator 41, when the water level rises, the float 412 rises due to buoyancy, and when the float 412 comes into contact with the upper limit stopper 413, the buoyancy is transmitted, lifting the rod 411 and the shaft. When a predetermined or greater upward force is applied from the rod 411 and the shaft to the microswitch 410, the microswitch 410 turns ON. In this embodiment, the position of the upper limit stopper 413 is set to the second upper limit water level H2.

[0022] Furthermore, when the water level drops below the second upper limit water level H2, the float 412 moves away from the upper limit stopper 413, and the upward force from the float 412 to the rod 411 and shaft no longer acts. On the other hand, no downward force greater than a predetermined value acts on the microswitch 410, so the microswitch 410 remains ON.

[0023] Furthermore, when the float 412 descends as the water level drops and reaches the lower limit stopper 414, the mass of the float 412 transmits a force to the shaft and rod 411. A downward force of a predetermined magnitude or greater acts on the microswitch 410 from the rod 411 and shaft, turning the microswitch 410 OFF. In this embodiment, the position of the lower limit stopper 414 is set to the second lower limit water level L2.

[0024] In this way, the float type water level gauge 41 has the microswitch 410 turned ON when the water level rises to the second upper limit water level H2, maintains the ON state while the water level falls from the second upper limit water level H2 to the second lower limit water level L2, and turns OFF when the water level falls below the second lower limit water level L2. The float type water level gauge 41 is also provided at the top of the water level detection unit installation groove 10 so as to protrude above the water level detection unit installation groove 10.

[0025] 2, the float-type water level gauge 41 can detect a second lower limit water level L2 that is set above the first upper limit water level H1 of the electrode-type water level gauge 40, and a second upper limit water level H2 that is set above the second lower limit water level L2. In other words, the water level detection position of the electrode-type water level gauge 40 is located below the water level detection position of the float-type water level gauge 41.

[0026] The drainage pit 1 according to this embodiment controls the operation of the drainage section 3 based on at least one of the detection signal of the electrode-type water level gauge 40 and the detection signal of the float-type water level gauge 41. Details will be described later.

[0027] Next, the drainage unit 3 as a drainage device will be described. The drainage unit 3 is capable of draining liquid to the outside. For example, the drainage unit 3 has a drainage pump 30 that sucks water from the drainage pit 1, and a drainage pipe 31 that directs the water sucked from the drainage pump 30 to an external drainage ditch. In this embodiment, the drainage pump 30 performs a predetermined operation by a control circuit 50 based on a detection signal from the water level detection unit 4. The drainage pump 30 is also provided on the bottom surface of the water level detection unit installation ditch 10.

[0028] Next, the control circuit 50 will be described. The control circuit 50 includes circuits for water level control, such as a terminal block 500 for connection to the water level detection unit 4 as shown in Figures 2 and 3, a known self-holding circuit using a relay switch, etc., and a circuit for output to the drainage pump 30. The terminal block 500 is provided with terminals 501, 502, 503, and 504, and wiring between the electrode-type water level gauge 40 of the water level detection unit 4 and the float-type water level gauge 41 is connected to the terminal block 500.

[0029] For example, the terminal 501 is connected to the wiring between the common electrode 401 of the electrode type water level gauge 40 and one of the two wirings of the float type water level gauge 41. The terminal 502 is connected to the wiring between the L1 water level detection electrode 402 of the electrode type water level gauge 40. The terminal 503 is connected to the wiring between the H1 water level detection electrode 403 of the electrode type water level gauge 40 and the remaining wiring of the two wirings of the float type water level gauge 41.

[0030] In the control circuit 50 according to this embodiment, for example, the terminal 502 is connected to the negative wiring of the power supply of the relay switch in the self-holding circuit. The terminal 503 is connected to the negative wiring of the power supply of the relay coil in the self-holding circuit and to the negative wiring of the power supply of the circuit for output to the drainage pump 30.

[0031] For example, when terminal 503 is energized, the relay switch is turned ON, and an output is sent to the drain pump 30, starting the drain pump 30. Furthermore, in the control circuit 50, if terminal 503 is energized while terminal 502 is energized, as long as terminal 502 is energized, even if terminal 503 is no longer energized, current is passed through the relay coil via terminal 502 and the relay switch in the ON state, and the ON state of the relay switch is maintained.

[0032] Furthermore, power continues to flow to the circuit for output to the drain pump 30 via terminal 502 and the relay switch in the ON state, and the operation of the drain pump 30 also continues. When power is no longer flowing to terminal 502, power also no longer flows to the relay coil via terminal 502 and the relay switch in the ON state, so the relay switch turns OFF, power no longer flows to the circuit for output to the drain pump 30, and the operation of the drain pump 30 stops.

[0033] Next, water level control in the drainage pit 1 using the drainage pump 30 will be described with reference to Fig. 4. Fig. 4 is a flowchart for explaining an example of the flow of drainage treatment according to one embodiment of the present invention, and shows water level control in the drainage pit 1 according to one embodiment of the present invention when the water level below the first lower limit water level L1 rises.

[0034] First, the water level in the drainage pit 1 rises to the first upper water level H1, and the H1 water level detection electrode 403 of the electrode-type water level gauge 40 comes into contact with the water. At this time, if the water accumulated in the drainage pit 1 is conductive, the common electrode 401 and the H1 water level detection electrode 403 are energized (step S10: YES), and the drainage pump 30 is started (step S11).

[0035] As the drain pump 30 operates, water in the drain pit 1 is drained, and the water level drops. Even if the water level in the drain pit 1 falls below the first upper limit water level H1, the drain pump 30 remains activated because the common electrode 401 and the L1 water level detection electrode 402 are electrically connected. Next, when the water level in the drain pit 1 falls below the first lower limit water level L1 (step S12: YES), the activated state of the drain pump 30 is released, and the drain pump 30 stops (step S13).

[0036] On the other hand, if the water accumulated in the drainage pit 1 is low-conductivity water such as pure water, no current flows between the common electrode 401 and the H1 water level detection electrode 403 (step S10: NO). In this case, the water level continues to rise, and the rising water comes into contact with the float 412 of the float-type water level indicator 41. The float 412 rises due to the buoyancy of the rising water and comes into contact with the upper limit stopper 413. When the buoyancy of the float 412 acting on the upper limit stopper 413 exceeds a predetermined force, the rod 411 and the shaft are lifted, turning on the microswitch 410 (step S14), and starting the drainage pump 30 (step S15).

[0037] When the drainage pump 30 operates, the water in the drainage pit 1 is discharged, and the water level drops. Note that since no downward force greater than a predetermined value is applied to the rod 411 and the shaft, the microswitch 410 remains ON.

[0038] Next, when the water level in the drainage pit 1 reaches the second lower limit water level L2, the float 412, which has descended as the water level drops, comes into contact with the lower limit stopper 414. When the water level drops further and the force exerted by the mass of the float 412 on the lower limit stopper 414 exceeds a predetermined force, the shaft and rod 411 are lowered, the ON state of the microswitch 410 is released (step S16: YES), and the drainage pump 30 stops (step S17).

[0039] The drainage pit 1 configured as described above comprises an electrode-type water level gauge 40 that detects the water level based on the state of conduction of an electrode that is in contact with the liquid and conducts electricity, a float-type water level gauge 41 that detects the water level based on the movement of a float that corresponds to the level of the liquid surface, and a drainage section 3 that can drain the liquid to the outside, and controls the operation of the drainage section 3 based on at least one of the detection signals of the electrode-type water level gauge 40 and the float-type water level gauge 41.

[0040] As a result, in the drainage pit 1 according to the present invention, even if the water accumulating in the drainage pit 1 is pure water and the electrode-type water level gauge 40 cannot detect the water level, the float-type water level gauge 41 can detect the water level, and the drainage unit 3 can be activated and drainage treatment can be performed based on the detection signal of the float-type water level gauge 41. On the other hand, even if the water accumulating in the drainage pit 1 is water that has dirt or the like adhering to the float-type water level gauge 41, which reduces its detection performance, the electrode-type water level gauge 40 can detect the water level, and the drainage unit 3 can be activated and drainage treatment can be performed based on the detection signal of the electrode-type water level gauge 40. Therefore, the drainage pit 1 according to the present invention can more reliably automatically drain accumulating water.

[0041] Furthermore, the position at which the electrode-type water level gauge 40 detects the water level is located lower than the position at which the float-type water level gauge 41 detects the water level.

[0042] As a result, in the drainage pit 1 according to the present invention, as water accumulates in the drainage pit 1, the electrode-type water level gauge 40 comes into contact with the water earlier than the float-type water level gauge 41. If the accumulating water contains impurities that will cause dirt to adhere to the float-type water level gauge 41, the drainage pit 1 will detect the water with the electrode-type water level gauge 40 and start the drainage unit 3 based on the detection signal from the electrode-type water level gauge 40 to perform drainage processing, thereby preventing dirt and the like from adhering to the float-type water level gauge 41.

[0043] In addition, the electrode-type water level gauge 40 is capable of detecting a first lower limit water level L1 and a first upper limit water level H1, and the float-type water level gauge 41 is capable of detecting a second lower limit water level L2 and a second upper limit water level H2, and operates the drainage section 3 when it detects the first upper limit water level H1 or the second upper limit water level H2, and stops the operation of the drainage section 3 when it detects the first lower limit water level L1 or the second lower limit water level L2.

[0044] This allows the control circuit 50 of the drainage pit 1 to start and stop the drainage section 3 based on the detection signal of the electrode-type water level gauge 40 or the detection signal of the float-type water level gauge 41, thereby enabling more accurate control of the drainage process.

[0045] A water level detection unit installation groove 10 is formed at the bottom, and an electrode type water level gauge 40, a float type water level gauge 41, and a drainage unit 3 are provided in the water level detection unit installation groove 10.

[0046] This allows devices such as the drainage pump 30 of the drainage section 3 to be stored below the bottom of the drainage pit 1, allowing the space within the drainage pit 1 to be used more effectively.

[0047] [Variations] The present invention is not limited to the above-described embodiment, and any modifications and improvements that can achieve the object of the present invention are included in the present invention. For example, the arrangement of the water level detection unit 4 and the drainage unit 3 described above is an example, and the present invention is not limited to these.

[0048] For example, the drainage pit 1 according to the present invention stops the pump when the first lower limit water level L1 is detected after the first upper limit water level H1 is detected, but the pump may also be stopped when the first upper limit water level H1 is detected after the second upper limit water level H2 is detected.Furthermore, the pump may also be stopped when the first lower limit water level L1 is detected after the second upper limit water level H2 is detected.

[0049] In addition, in this embodiment, the operation of the drainage pump 30 based on the detection signal from the water level detector 4 is controlled by hardware such as the control circuit 50, but this is not limiting and the control can be executed by hardware of other configurations, or by software implemented by a processor that executes arithmetic processing. Processors that execute arithmetic processing include those configured by various types of stand-alone processing devices such as single processors, multiprocessors, and multicore processors, as well as those that combine these various types of processing devices with processing circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field-Programmable Gate Arrays).

[0050] When a series of processes is executed by software, the programs that make up the software are installed into a computer or the like from a network or a recording medium. The computer may be a computer built into dedicated hardware. Alternatively, the computer may be a computer that can execute various functions by installing various programs, such as a general-purpose personal computer.

[0051] Recording media containing such programs include not only removable media distributed separately from the device main body in order to provide the program to the user, but also recording media provided to the user in a state where the program is pre-installed in the device main body. Removable media include, for example, magnetic disks (including floppy disks), optical disks, and magneto-optical disks. Optical disks include, for example, CD-ROMs (Compact Disc-Read Only Memory), DVDs (Digital Versatile Discs), and Blu-ray (registered trademark) Discs. Magneto-optical disks include, for example, MDs (Mini-Discs). Recording media provided to the user in a state where the program is pre-installed in the device main body include, for example, ROMs on which the program is recorded, hard disks, etc. [Explanation of symbols]

[0052] 1. Drainage pit 3 Drainage section 40 Electrode water level gauge 41 Float type water level gauge 50 control circuit

Claims

1. an electrode-type water level meter that detects the water level based on the state of conduction of electrodes that contact the liquid and conduct electricity; a float-type water level meter that detects the water level based on the movement of a float that corresponds to the water level of the liquid; a drainage device capable of draining the liquid to the outside; Equipped with The water level detection position of the electrode-type water level meter is located below the water level detection position of the float-type water level meter, A drainage pit that controls the operation of the drainage device based on at least one of the detection signal of the electrode type water level gauge and the detection signal of the float type water level gauge when the electrode type water level gauge and the float type water level gauge are in an operating state.

2. the electrode-type water level meter is capable of detecting a first lower limit water level and a first upper limit water level that is set at a position higher than the first lower limit water level; the float-type water level meter is capable of detecting a second lower limit water level and a second upper limit water level that is set at a position higher than the second lower limit water level; A drainage pit as described in claim 1, wherein the drainage device is operated when the first upper water level or the second upper water level is detected, and the operation of the drainage device is stopped when the first lower water level or the second lower water level is detected.

3. A groove is formed at the bottom, 3. The drainage pit according to claim 1, wherein the electrode-type water level gauge, the float-type water level gauge, and the drainage device are provided in the groove.

4. A drainage method carried out in a drainage pit, comprising: a control step of controlling the operation of a drainage device capable of draining the liquid to the outside based on at least one of the detection signals of the electrode type water level meter and the float type water level meter, which detects the water level based on the state of conduction of an electrode that contacts the liquid and conducts electricity, when the electrode type water level meter and the float type water level meter, which detects the water level based on the movement of a float associated with the liquid level, are in an operating state; A drainage method in which the water level detection position of the electrode type water level meter is located below the water level detection position of the float type water level meter.

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