Coal storage yard rainwater drainage facility

Abstract

To provide a coal yard rainwater discharge facility which can avoid such a malfunction that coals in a coal yard are covered with rainwater by quickly discharging the rainwater from the coal yard even if a quantity of the rainwater is increased, and allows the use of an existing facility as it is.SOLUTION: A coal yard rainwater discharge facility comprises: a water collection tank 2 for collecting rainwater in a coal yard; drain water storage tanks 6, 7 for transferring the rainwater stored in the water collection tank 2 to a facility for treating it so as to satisfy a prescribed environment reference; and an emergency tank 12 for transferring the rainwater to the water collection tank 2; and an A-raw water pump (first raw water pump) 4 and a B-raw water pump (second raw water pump) 5 for transferring the rainwater in the water collection tank 2. The coal yard rainwater discharge facility also comprises a normal operation mode for transferring the rainwater collected in the water collection tank 2 to the drain water collection tanks 6, 7 by automatically starting and stopping at least either of the first raw water pump and the second raw water pump according to water levels of the water collection tank 2 and the drain water storage tank 7, and an emergency operation mode for transferring the rainwater collected in the water collection tank 2 to the emergency tank 12 by automatically starting and stopping the second raw water pump 5 on the basis of only the water level of the water collection tank 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coal stockyard rainwater drainage facility for properly draining rainwater that falls on a coal stockyard. [Background technology]

[0002] Coal used in thermal power plants is temporarily stored in a coal yard after being unloaded from a ship, and then the required amount is used as fuel in the boiler. If the coal yard is located outdoors, rain that falls on the yard comes into contact with the coal and turns into dark, muddy water (yard drainage) containing coal dust. For this reason, this type of rainwater cannot be discharged directly outside the facility, so it is treated to meet specified environmental standards (specified turbidity and pH value) before being discharged outside the facility. However, if heavy rain falls on a coal yard, the excess rainwater cannot be disposed of, and there is a concern that the coal in the yard may become flooded.

[0003] Therefore, in the past, in order to deal with heavy rainfall at a coal yard, a water treatment facility for a coal conveying facility was provided that included a drainage tank that receives rainwater from the coal yard, a make-up water tank that guides the rainwater from the drainage tank through a neutralization tank, a flocculation facility that introduces a portion of the rainwater guided from the drainage tank to the neutralization tank through a flow path for external discharge of rainwater, and an external drainage channel for discharging a portion of the water in the make-up water tank outside the system. During heavy rainfall, rainwater from the coal yard is guided to the drainage tank, and then introduced from the drainage tank through the flow path for external discharge of rainwater to the flocculation facility. The supernatant water from which solid suspended matter has been flocculated in the flocculation facility is guided to the make-up water tank, and then discharged from the make-up water tank through the external drainage channel (see Patent Document 1). A proposed water treatment facility for coal conveying equipment (see Patent Document 2) is designed to, when heavy rain falls at a coal storage yard and exceeds the capacity of the wastewater storage tank, guide the rainwater that has accumulated in the wastewater storage tank to a neutralization tank to neutralize it, guide the neutralized wastewater in the neutralization tank to a flocculation system to flocculate and separate solid suspended matter such as coal powder, guide the supernatant water after the solid suspended matter has been separated in the flocculation system to a wastewater filtration system to filter it, and discharge the treated water purified in the wastewater filtration system outside the system via an external discharge flow path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 9-85226 [Patent Document 2] Patent Publication No. 9-75949 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the amount of rainfall becomes abnormally high, there is a limit to the processing capacity for draining rainwater outside the system. Therefore, when the capacity of the drainage tank reaches its limit and the rainwater from the coal yard can no longer be transferred to the drainage tank, the drainage of rainwater outside the system cannot keep up, and there is still concern that the coal in the coal yard will be flooded. In this case, it may be possible to increase the capacity of existing wastewater storage tanks and treatment equipment that neutralizes, settles, and filters rainwater, but this would require extensive modifications to the equipment, making it unrealistic.

[0006] The present invention has been made in consideration of the above circumstances, and its main object is to provide a coal stockyard rainwater drainage facility that can quickly drain rainwater from the coal stockyard even in the event of heavy rainfall, thereby avoiding the inconvenience of the coal in the coal stockyard becoming submerged in water, and that can utilize existing facilities as they are. [Means for solving the problem]

[0007] In order to achieve the above object, the coal stockyard rainwater drainage facility of the present invention comprises: A water collection tank that temporarily collects rainwater accumulated in the coal storage area; a drainage tank for temporarily storing the rainwater collected in the water collection tank in order to transport it to a facility for treating the rainwater so that it meets predetermined environmental standards; an emergency tank capable of receiving the rainwater collected in the water collection tank; a first raw water pump and a second raw water pump for transferring the rainwater collected in the water collection tank; The transfer of rainwater from the water collection tank to the drainage tank is performed by at least one of the first raw water pump and the second raw water pump, and the transfer of rainwater from the water collection tank to the emergency tank is performed by the second raw water pump, a normal operation mode in which the rainwater collected in the water collection tank is transferred to the wastewater storage tank by automatically starting and stopping at least one of the first raw water pump and the second raw water pump according to the water levels of the water collection tank and the wastewater storage tank; a first emergency operation mode in which the first raw water pump is automatically started and stopped according to the water levels of the water collection tank and the wastewater storage tank to transfer the rainwater collected in the water collection tank to the wastewater storage tank, and the second raw water pump is automatically started and stopped based only on the water level of the water collection tank to transfer the rainwater to the emergency tank; It is characterized by having the following.

[0008] Here, the automatic start / stop of the first raw water pump and the second raw water pump in normal operation mode is preferably such that one is started when the water level in the water collection tank reaches a first judgment water level, and the other is started when the water level in the water collection tank reaches or exceeds a second judgment water level that is higher than the first judgment water level. In addition, in the first emergency operation mode, the second raw water pump is started when the water level in the water collection tank becomes equal to or higher than the second judgment water level, and the second raw water pump is stopped when the water level in the water collection tank becomes equal to or lower than a third judgment water level that is lower than the first judgment water level.

[0009] Therefore, by installing an emergency tank and setting up the first emergency operation mode, by switching to this first emergency operation mode, if the water level in the water collection tank becomes abnormally high, the second raw water pump will automatically start and the rainwater in the water collection tank will be transferred to the emergency tank until the water level in the water collection tank returns to a low level, so a temporary evacuation site can be secured for rainwater that cannot be discharged using the normal drainage system, making it possible to prevent rainwater from overflowing from the water collection tank and accumulating in the coal storage yard.In addition, since it is possible to deal with this by installing an emergency tank while utilizing existing facilities as is, there is no need for major equipment modifications.

[0010] In addition, the coal storage yard rainwater drainage device according to the present invention may further include a second emergency operation mode in which the first raw water pump is automatically started and stopped depending on the water levels of the water collection tank and the drainage tank to transfer the rainwater collected in the water collection tank to the drainage tank, and the second raw water pump is manually started forcibly to transfer the rainwater to the emergency tank. By providing this second emergency operation mode, in the event of an emergency when automatic operation is not enough, it is possible to forcibly start the second raw water pump and transfer the rainwater from the collection tank to the emergency tank.

[0011] Here, in the second emergency operation mode, after the second raw water pump is forcibly started manually, the second raw water pump is preferably stopped when the water level in the water collection tank falls below a fourth judgment water level that is lower than the third judgment water level. With this configuration, it is possible to continue transferring rainwater from the water collection tank to the emergency tank for a long period of time until the water level in the water collection tank becomes abnormally low, so that a temporary evacuation site for rainwater can be secured even in an emergency when the amount of rainfall becomes abnormally high, and it is possible to prevent rainwater from overflowing from the water collection tank and accumulating in the coal storage yard.

[0012] It is preferable to provide an operation selection switch and switch between the normal operation mode and the emergency operation mode by switching this operation selection switch. [Effects of the Invention]

[0013] As described above, an emergency tank is provided separate from the wastewater storage tank, and the rainwater in the water collection tank is transferred to the emergency tank based solely on the water level in the water collection tank (for example, if the water level in the water collection tank becomes abnormally high, the second raw water pump is automatically started to transfer the rainwater in the water collection tank to the emergency tank until the water level in the water collection tank becomes low), or the rainwater in the water collection tank is forcibly transferred to the emergency tank (for example, the second raw water pump is forcibly started to transfer the rainwater in the water collection tank to the emergency tank until the water level in the water collection tank becomes abnormally low).This makes it possible to evacuate rainwater that cannot be discharged during normal operation to a temporary emergency tank, and prevents rainwater from overflowing from the water collection tank and accumulating in the coal storage yard. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating the overall configuration of a coal yard rainwater drainage facility according to the present invention. [Figure 2] Figure 2(a) is a table showing the water level of the water collection tank (the distance from the top of the water collection tank to the water surface) at which the level switch of the water collection tank will operate, and Figure 2(b) is a table showing the water level (the distance from the top of the wastewater storage tank to the water surface) at which the level switch of the No. 2 wastewater storage tank will operate. [Figure 3] FIG. 3 is a table illustrating an example of operation of the coal yard rainwater drainage facility according to the present invention in the normal operation mode. [Figure 4] FIG. 4 is a block diagram showing examples of operation (startup and shutdown conditions) of the A raw water pump (first raw water pump) of the coal storage yard stormwater discharge facility of FIG. 1 in normal operation mode, first emergency operation mode, and second emergency operation mode. [Figure 5] FIG. 5 is a block diagram showing an example of operation (start and stop conditions) of the B raw water pump (second raw water pump) of the coal yard rainwater discharge facility of FIG. 1 in a normal operation mode. [Figure 6] Figure 6(a) is a table explaining an example of operation of the coal yard stormwater drainage facility of the present invention in the first emergency operation mode, and Figure 6(b) is a table explaining an example of operation of the coal yard stormwater drainage facility of the present invention in the second emergency operation mode. [Figure 7] FIG. 7 is a block diagram showing an example of operation (start and stop conditions) of the B raw water pump (second raw water pump) of the coal yard storm water discharge facility of FIG. 1 in the first emergency operation mode. [Figure 8] FIG. 8 is a block diagram showing an example of operation (start and stop conditions) of the B raw water pump (second raw water pump) of the coal yard storm water discharge facility of FIG. 1 in the second emergency operation mode. BEST MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0016] FIG. 1 shows a coal stockyard rainwater drainage facility 1 according to the present invention. A moat (not shown) is provided beside the coal stockyard to store rainwater that falls on the coal stockyard, and a water collection tank 2 is provided beside the moat to temporarily collect the rainwater stored in the moat. This water collection tank 2 is provided with a level switch 3 that detects the water level of the rainwater collected therein. As shown in Figure 2(a), this level switch 3 is configured to detect when the water level in the water collection tank 2 reaches an abnormally high water level (HH) of 1300 mm from the top, a high water level (H) of 2000 mm from the top, a low water level (L) of 3100 mm from the top, or an abnormally low water level (LL) of 3450 mm from the top.

[0017] The rainwater collected in the water collection tank 2 is sent to the drainage tanks 6, 7 by starting at least one of the A raw water pump (corresponding to the first raw water pump) 4 and the B raw water pump (corresponding to the second raw water pump) 5. These drainage tanks 6, 7 include the No. 1 drainage tank 6 and the No. 2 drainage tank 7, and the rainwater sent from the water collection tank 2 is first sent to the No. 1 drainage tank 6, and then stored in the No. 2 drainage tank 7 via the No. 1 drainage tank 6.

[0018] The reason for providing two drainage tanks in this way is to use No. 1 drainage tank 6 as a condenser tank (a tank that suppresses fluctuations in the water level of rainwater transferred from collection tank 2 to No. 1 drainage tank 6) to prevent sudden changes in the water level of No. 2 drainage tank 7, and to enable a stable, constant amount of water to be supplied from No. 2 drainage tank 7 to the coal storage yard rainwater treatment device described below.

[0019] Therefore, the No. 1 drainage tank 6 is not provided with a level switch to detect its water level, and the No. 2 drainage tank 7 is provided with a level switch 8 only. In this example, as shown in Figure 2(b), the level switch 8 provided in the No. 2 drainage tank 7 is designed to detect an abnormally high water level (HH) when the water level in the No. 2 drainage tank 7 reaches 700 mm from the top, and a high water level (H) when the water level reaches 1,400 mm from the top.

[0020] A certain amount of rainwater is transferred from the No. 2 wastewater storage tank 7 to a coal yard rainwater treatment device via a water pump A 9 and a water pump B 10 connected in parallel downstream of the No. 2 wastewater storage tank 7. This coal yard rainwater treatment device is known per se and treats the rainwater that falls on the coal yard so that the water quality meets specified environmental standards (specified turbidity and specified pH value).

[0021] In the present invention, an emergency tank 12 is provided in the downstream system of the B raw water pump 5 via a branch path 11 in the coal yard rainwater discharge facility described above, as a temporary evacuation site for rainwater. This branch path 11 is connected between the B raw water pump 5 and a confluence point α where the rainwater delivered from the A raw water pump 4 and the rainwater delivered from the B raw water pump 5 are confluenced, and this branch path 11 is opened and closed by a tank valve 13. In addition, a drainage tank valve 15 is provided between the confluence point α and a connection point β with the branch path 11 downstream of the B raw water pump 5. Therefore, by alternately switching the opening and closing of the tank valve 13 and the drainage tank valve 15, it is possible to switch between sending the rainwater delivered from the B raw water pump 5 to the emergency tank 12 or to the drainage tanks 6 and 7.

[0022] The emergency tank 12 is provided with an auxiliary valve 14 for repair purposes. This auxiliary valve 14 is used to isolate the tank body from other systems when safely repairing the tank body of the emergency tank 12, and is normally set to the open position.

[0023] As shown in Figure 1, the coal storage yard rainwater discharge facility 1 is also provided with an operation selection switch 21, pump mode selection switches 22 and 23 for switching the operating modes of raw water pump A 4 and raw water pump B 5, and a pump selection switch 24 for selecting the raw water pump to be started with priority. The operation selection switch 21 is a switch for switching the operation of the coal yard rainwater drainage facility between a normal operation mode and an emergency operation mode (tank transfer operation). Pump mode selection switches 22, 23 are provided on each of raw water pumps A 4 and B 5, and are switches that switch the operation of the raw water pumps (raw water pump A 4, raw water pump B 5) between an on mode ("on") that forcibly starts them, an off mode ("off") that forcibly stops them, or an automatic mode ("auto") that automatically starts and stops them. The pump selection switch 24 is a switch for selecting a pump to be activated with priority when transferring rainwater from the water collection tank 2.

[0024] Next, an example of operation for managing the discharge of rainwater using the coal yard rainwater discharge facility 1 described above will be described. First, when normal operation mode is selected by operation selector switch 21 and raw water pump A 4 and raw water pump B 5 are set to automatic mode by pump mode selector switches 22 and 23, the process shown in Figure 3 is carried out. In this process, the raw water pump to be started first is automatically selected, preventing one raw water pump from starting first. This is to extend the life of the electric motors by leveling out the number of times raw water pump A 4 and raw water pump B 5 are started, and each raw water pump can be used as both the main pump and the standby pump.

[0025] When the A raw water pump 4 is automatically selected as the raw water pump to be started with priority, this A raw water pump 4 is started when the water level in the water collection tank 2 reaches the high water level (H). Thereafter, as will be described later, when the water level in the water collection tank 2 falls below the low water level (L) or when the water level in the No. 2 wastewater storage tank 7 reaches the abnormally high water level (HH) or above, the A raw water pump 4 is stopped.

[0026] If the water level in the water collection tank 2 does not decrease despite this movement of the A raw water pump 4, but instead rises further to an abnormally high water level (HH), the B raw water pump 5 is started again, and the two raw water pumps A and B transfer the rainwater in the water collection tank 2. After that, as will be described later, the B raw water pump 5 is stopped when the water level in the water collection tank 2 falls below the low water level (L) or when the water level in the No. 2 drainage tank 7 exceeds the abnormally high water level (HH).

[0027] When raw water pump B 5 is automatically selected as the raw water pump to be started with priority, the above operation is performed with raw water pump B 5 as the main pump and raw water pump A 4 as the backup pump.

[0028] That is, the B raw water pump 5 is started when the water level in the water collection tank 2 reaches the high water level (H), and is then stopped when the water level in the water collection tank 2 falls below the low water level (L) or when the water level in the No. 2 drainage tank 7 reaches the abnormally high water level (HH) or above. Furthermore, if the water level in the water collection tank 2 does not decrease despite the operation of the B raw water pump 5 and continues to rise to an abnormally high water level (HH), the A raw water pump 4 is started up again as a backup, and the two raw water pumps, A and B, transfer the rainwater in the water collection tank 2. After that, the A raw water pump 4 is also stopped when the water level in the water collection tank 2 falls below the low water level (L) or when the water level in the No. 2 drainage storage tank 7 rises above the abnormally high water level (HH).

[0029] To control the normal operation mode in this way, specifically, the A raw water pump 4 is controlled to start and stop as shown in the block diagram of FIG. 4, and the B raw water pump 5 is controlled to start and stop as shown in the block diagram of FIG. 5. In the block diagram, a white square indicates an AND circuit, a white circle indicates an OR circuit, and a white rectangle with an x ​​indicates a NOT circuit.

[0030] In Figure 4, the condition for starting the A raw water pump 4 in normal operation mode is when one of the following conditions is met. However, this is premised on the assumption that there is no electrical failure, and if there is an electrical failure, the pump will stop. (1) The A raw water pump 4 starts when the pump mode selection switch 22 is set to “ON” and the water level in the water collection tank 2 is not below the abnormally low water level (LL) and the water level in the No. 2 drainage tank 7 is not at the abnormally high water level (HH). If the amount of water stored in the No. 2 drainage tank 7 is equal to or greater than the abnormally high water level (HH), the A raw water pump 4 will not start, and rainwater will not be sent from the water collection tank 2 to the drainage tank 6. In this case, there is a risk of rainwater overflowing from the water collection tank 2, so the operation selection switch 21 is switched to "tank transfer," as described below.

[0031] (2) The A raw water pump 4 is activated when "self" is selected with the pump mode selector switch 22, and the B raw water pump 5 is activated when "self" is selected with the pump mode selector switch 23 and the A raw water pump 4 is selected with the pump selector switch 24, the water level in the water collection tank 2 is above the high water level (H) (once it reaches the high water level (H) or above, this requirement is maintained until it drops to the low water level (L)), and the water level in the No. 2 wastewater storage tank 7 is below the high water level (H) (once it drops below the high water level (H) or below, this requirement is maintained until it drops to the abnormally high water level (HH)). In other words, when the water level in the water collection tank 2 is above the high water level (H), the A raw water pump 4 is activated to continue transferring rainwater from the water collection tank 2 until it drops to the low water level (L), and the A raw water pump 4 is activated so that the water level in the No. 2 wastewater storage tank 7 is maintained above the high water level (H). The water level of the No. 2 drainage storage tank 7 is kept above the high water level (H) in order to avoid the water level of the No. 2 drainage storage tank 7 falling below the high water level (H) as much as possible, since it is necessary to always ensure a minimum operating amount of water from the No. 2 drainage storage tank 7 to the coal storage yard rainwater treatment device by the water supply pumps 9 and 10. Therefore, during automatic operation, the A raw water pump 4 is automatically started and stopped based on the water level in the water collection tank 2 and the water level in the No. 2 drainage storage tank 7.

[0032] (3) The A raw water pump 4 is started when "self" is selected with the pump mode selection switch 22, and the B raw water pump 5 is started when "self" is selected with the pump mode selection switch 23 and the B raw water pump 5 is selected with the pump selection switch 24, and the water level in the water collection tank 2 reaches the abnormally high water level (HH) or above (once it reaches the abnormally high water level (HH) or above, this requirement is maintained until it reaches the low water level (L)), and the water level in the No. 2 drainage storage tank 7 once falls below the high water level (H) but does not reach the abnormally high water level (HH). Therefore, when raw water pump B 5 is selected with pump selection switch 24, if the water level in water collection tank 2 exceeds the abnormally high water level (HH) even when only raw water pump B 5 is started, raw water pump A 4 is started as a backup, and the two raw water pumps transfer the rainwater in water collection tank 2 to drainage storage tanks 6 and 7, preventing the rainwater in water collection tank 2 from overflowing.

[0033] The A raw water pump 4 is stopped in any of the following cases. (1) When the pump mode selection switch 22 is set to "OFF" (manual) (2) When the water level in Water Collection Tank 2 is below the abnormally low water level (LL) (3) If the above startup conditions (2) and (3) are not met

[0034] In Figure 5, the condition for starting the B raw water pump 5 in normal operation mode is when one of the following conditions is met. However, this is premised on the assumption that there is no electrical failure, and if there is an electrical failure, the pump will stop. (1) The B raw water pump 5 starts when the pump mode selection switch 23 is set to “ON” and the water level in the water collection tank 2 is not below the abnormally low water level (LL) and the water level in the No. 2 drainage tank 7 is not above the abnormally high water level (HH). If the water level in the No. 2 drainage tank 7 is above the abnormally high water level (HH), the B raw water pump 5 will not start, and rainwater will not be sent from the water collection tank 2 to the drainage tank 6. In this case, there is a risk of rainwater overflowing from the water collection tank 2, so the operation selection switch 21 is switched to "tank transfer," as described below. (2) The B raw water pump 5 is activated when the pump mode selector switch 23 is set to "self" and the B raw water pump 5 is selected by the pump selector switch 24, the water level in the water collection tank 2 is above the high water level (H) (once it reaches the high water level (H) or above, this requirement is maintained until it drops to the low water level (L)), and the water level in the No. 2 wastewater storage tank 7 is below the high water level (H) (once it drops below the high water level (H) or below, this requirement is maintained until it drops to the abnormally high water level (HH)). In other words, when the water level in the water collection tank 2 is above the high water level (H), the B raw water pump 5 continues to transfer rainwater from the water collection tank 2 until it drops to the low water level (L), and the B raw water pump 5 is activated so that the water level in the No. 2 wastewater storage tank 7 is maintained above the high water level (H). Therefore, during automatic operation, the B raw water pump 5 is automatically started and stopped based on the water level in the water collection tank 2 and the water level in the No. 2 drainage storage tank 7. (3) The B raw water pump 5 is started when "self" is selected with the pump mode selection switch 23, and the A raw water pump 4 is started when "self" is selected with the pump mode selection switch 22 and the A raw water pump 4 is selected with the pump selection switch 24, and the water level in the water collection tank 2 reaches the abnormally high water level (HH) or above (once it reaches the abnormally high water level (HH) or above, this requirement is maintained until it reaches the low water level (L)), and the water level in the No. 2 drainage storage tank 7 once falls below the high water level (H) but does not reach the abnormally high water level (HH). Therefore, when raw water pump A 4 is selected with pump selection switch 24, if only raw water pump A 4 is started and the water level in water collection tank 2 exceeds the abnormally high water level (HH), raw water pump B 5 is started as a backup, and the two raw water pumps transfer the rainwater in water collection tank 2 to drainage storage tanks 6 and 7, preventing the rainwater in water collection tank 2 from overflowing.

[0035] The condition for stopping the B raw water pump 5 is any of the following cases. (1) When the pump mode selection switch 23 is set to "off" (manual), the B raw water pump 5 (2) When the water level in Water Collection Tank 2 falls below the abnormally low water level (LL), (3) If the above startup conditions (2) and (3) are not met

[0036] Therefore, in the normal operation mode, the start and stop of both the A raw water pump 4 and the B raw water pump 5 are controlled based on the water level in the water collection tank 2 and the water level in the No. 2 wastewater storage tank 7.

[0037] Next, when control in the normal operation mode is not possible, that is, when draining the rainwater from the water collection tank 2 to the wastewater storage tank alone is not enough, control in the emergency operation mode is performed as follows. This emergency operation mode transfers the rainwater in the water collection tank 2 to the emergency tank 12 as an emergency evacuation, and has the following first and second emergency operation modes.

[0038] As shown in Figure 6(a), the first emergency operation mode is performed when "tank transfer" is selected with the operation selector switch 21 and "auto" is selected for both the A raw water pump 4 and the B raw water pump 5 with the pump mode selector switches 22 and 23, in which the A raw water pump 4 is fixed as the main pump and the B raw water pump 5 is fixed as the standby pump. With this setting, the A raw water pump 4 starts when the water level in the water collection tank 2 reaches the high water level (H), and transfers the rainwater from the water collection tank 2 to the wastewater storage tanks 6 and 7. Thereafter, the A raw water pump 4 is designed to automatically start and stop based on the water levels in the water collection tank 2 and the No. 2 wastewater storage tank 7.

[0039] Furthermore, the B raw water pump 5 is automatically started and stopped based only on the water level in the water collection tank 2, and starts when the water level in the water collection tank 2 reaches an abnormally high water level (HH) and transfers the rainwater in the water collection tank 2 to the emergency tank 12. After that, it automatically stops when the water level in the water collection tank 2 falls below the low water level (L).

[0040] In order to control this emergency operation mode, the start-up and stop of the A raw water pump 4 is controlled as shown in the block diagram of Figure 4, and the start-up and stop of the B raw water pump 5 is controlled as shown in the block diagram of Figure 7.

[0041] The automatic start / stop conditions for the A raw water pump 4 are the same as those described above, so a description thereof will be omitted. Below, the automatic start / stop conditions for the B raw water pump 5 in the first emergency operation mode will be described. The raw water pump B 5 starts when the following conditions are met. However, this is on the premise that there is no electrical failure, and if there is an electrical failure, it will stop.

[0042] The B raw water pump 5 selects "self" with the pump mode selection switch 23 and "tank transfer" with the operation selection switch 21, and operates until the water level in the water collection tank 2 reaches or exceeds the abnormally high water level (HH) and then falls to the low water level (L).

[0043] The condition for stopping the B raw water pump 5 is any of the following cases. (1) When the pump mode selection switch 23 is set to "off" (manual), the B raw water pump 5 (2) When the water level in the water collection tank 2 falls below the low water level (L), (3) If the above startup conditions (2) and (3) are not met

[0044] Therefore, in the first emergency operation mode, the start and stop of the A raw water pump 4 is controlled based on the water level of the water collection tank 2 and the water level of the No. 2 wastewater storage tank 7, but when the water level of the water collection tank 2 reaches an abnormally high water level (HH), the B raw water pump 5 is started to transfer the rainwater in the water collection tank 2 to the emergency tank 12 as an emergency evacuation, and this state continues until the water level of the water collection tank 2 falls to a low water level (L). Therefore, it is possible to add rainwater that cannot be discharged in the normal operation mode to the wastewater storage tanks 6 and 7 and evacuate it to the temporary emergency tank 12, making it possible to prevent rainwater from overflowing from the water collection tank 2 and accumulating in the coal yard.

[0045] Next, the second emergency operation mode, which responds to a more urgent situation than the first emergency operation mode, performs the process shown in Fig. 6(b). That is, when "tank transfer" is selected with the operation selection switch 21 and the A raw water pump 4 is set to "ON" with the pump mode selection switches 22 and 23, but when the B raw water pump 5 is manually set to "ON," the B raw water pump 5 is immediately started to transfer the rainwater from the water collection tank 2 to the emergency tank 12.

[0046] In such an emergency, in order to transfer the rainwater in the water collection tank 2 by running the B raw water pump 5 for as long as possible, the pump is kept running until the water level in the water collection tank 2 falls below the abnormally low water level (LL) to ensure free capacity in the water collection tank 2. In this emergency operation mode, after the water level in the water collection tank 2 falls below the abnormally low water level (LL) and the B raw water pump 5 stops, the pump mode selection switch 23 of the B raw water pump 5 automatically switches from "ON" to "AUTO." In other words, the pump automatically switches from the second emergency operation mode to the first emergency operation mode, and control in the first emergency operation mode continues.

[0047] Therefore, in the second emergency operation mode, raw water pump A 4 is fixed as the main pump and raw water pump B 5 is fixed as the backup pump, but from the moment the second emergency operation mode is switched to, raw water pump B 5 transfers rainwater from the water collection tank 2 to the emergency tank 12, regardless of the water level in the water collection tank 2. After that, it is automatically stopped based only on the water level in the water collection tank 2, and when it is stopped, the system switches to the first emergency operation mode.

[0048] In order to control the second emergency operation mode, the A raw water pump 4 is controlled to start and stop as shown in the block diagram of Figure 4, and the B raw water pump is controlled to start and stop as shown in the block diagram of Figure 8.

[0049] The automatic start / stop conditions for raw water pump A 4 are the same as those described above, so a detailed explanation will be omitted. However, the automatic start / stop conditions for raw water pump B 5 in the second emergency operation mode will be explained below. Raw water pump B 5 will start when the following conditions are met. However, this is premised on the absence of an electrical failure; if there is an electrical failure, it will stop. That is, raw water pump B 5 starts when raw water pump B 5 is manually set to "ON" using pump mode selection switch 23, "tank transfer" is selected using operation selection switch 21, and the water level in water collection tank 2 is not below the abnormally low water level (LL), and then continues to run until the water level in water collection tank 2 reaches the abnormally low water level (LL).

[0050] The condition for stopping the B raw water pump 5 is any of the following cases. (1) When the pump mode selection switch 23 is set to "off" (manual), the B raw water pump 5 (2) When the water level in Water Collection Tank 2 falls below the abnormally low water level (LL), (3) If the above startup conditions (2) and (3) are not met

[0051] Therefore, in the second emergency operation mode, the start and stop of the A raw water pump 4 is controlled based on the water level in the water collection tank 2 and the water level in the No. 2 wastewater storage tank 7, and the water is transferred to the wastewater storage tanks 6 and 7, but the B raw water pump 5 begins to transfer the rainwater in the water collection tank 2 to the emergency tank 12 from the moment the B raw water pump 5 is manually switched to "on" using the pump mode selection switch 23, and then the B raw water pump 5 is started to continue to urgently transfer the rainwater in the water collection tank 2 to the emergency tank 12 until the water level in the water collection tank 2 reaches the abnormally low water level (LL).

[0052] Therefore, by adopting the second emergency operation mode described above, even if a large amount of rainwater falls on the coal yard, the rainwater in the water collection tank 2 can be immediately added to the drainage storage tanks 6 and 7 and transferred to the emergency tank 12, thereby evacuating the rainwater from the coal yard, thereby eliminating the inconvenience of the water collection tank 2 overflowing and flooding the coal in the coal yard.

[0053] In an emergency where the coal in the coal yard is about to become flooded, it is reliable to have an operator manually switch to the second emergency operation mode (select the operation selection switch 21 to "tank transfer" and turn the B raw water pump 5 "on") to prevent flooding, but it is also possible to automatically switch to the second emergency operation mode when it detects that such an emergency is anticipated. For example, it is also possible to automatically switch from the normal operation mode to the emergency operation mode (tank transfer mode) when it detects that the amount of rainfall has exceeded a predetermined value or that the rate at which the water level in the water collection tank 2 is rising has exceeded a predetermined value. In addition, the opening and closing of the tank valve 13 and the drainage tank valve 15 when switching between normal operation mode and emergency operation mode (tank transfer mode) can be done manually or automatically in accordance with the switching of the operation selection switch 21.

[0054] Furthermore, in the above example, the emergency tank 12 is used as a tank for storing rainwater in an emergency, and it is not assumed that the stored rainwater will be discharged outside the facility. However, if it is assumed that the rainwater will be discharged outside the facility, it may be further transferred to a coal storage yard rainwater treatment device (shown by the dashed line in Figure 1) and treated to meet specified environmental standards (specified turbidity and pH value) before being discharged. [Explanation of symbols]

[0055] 1. Coal storage yard rainwater drainage facility 2 Water collection tank 4. No. 1 raw water pump 5. Second raw water pump 6 No.1 wastewater storage tank 7 No.2 wastewater storage tank 12 Emergency Tank 21 Operation selection switch

Claims

1. A water collection tank that temporarily collects rainwater accumulated in the coal storage area; a drainage tank for temporarily storing the rainwater collected in the water collection tank in order to transport it to a facility for treating the rainwater so that it meets predetermined environmental standards; an emergency tank capable of receiving the rainwater collected in the water collection tank; a first raw water pump and a second raw water pump for transporting the rainwater collected in the water collection tank, The transfer of rainwater from the water collection tank to the drainage tank is performed by at least one of the first raw water pump and the second raw water pump, and the transfer of rainwater from the water collection tank to the emergency tank is performed by the second raw water pump, a normal operation mode in which the rainwater collected in the water collection tank is transferred to the wastewater storage tank by automatically starting and stopping at least one of the first raw water pump and the second raw water pump according to the water levels of the water collection tank and the wastewater storage tank; a first emergency operation mode in which the first raw water pump is automatically started and stopped in accordance with the water levels of the water collection tank and the wastewater storage tank to transfer the rainwater collected in the water collection tank to the wastewater storage tank, and the second raw water pump is automatically started and stopped based only on the water level of the water collection tank to transfer the rainwater to the emergency tank; A coal storage yard rainwater drainage facility comprising:

2. a second emergency operation mode in which the first raw water pump is automatically started and stopped according to the water levels of the water collection tank and the wastewater storage tank to transfer the rainwater collected in the water collection tank to the wastewater storage tank, and the second raw water pump is manually started forcibly to transfer the rainwater to the emergency tank; 2. The coal yard rainwater drainage facility according to claim 1, further comprising:

3. 3. A coal yard rainwater drainage facility according to claim 1, wherein switching between the normal operation mode and the emergency operation mode is performed by switching an operation selection switch.

4. A coal yard rainwater drainage facility as described in any one of claims 1 to 3, characterized in that the automatic start / stop of the first raw water pump and the second raw water pump in the normal operation mode is such that one is started when the water level in the water collection tank reaches a first judgment water level, and the other is started when the water level in the water collection tank reaches or exceeds a second judgment water level that is higher than the first judgment water level.

5. A coal yard rainwater drainage facility as described in claim 4, characterized in that in the first emergency operation mode, the second raw water pump is started when the water level in the water collection tank becomes equal to or higher than the second judgment water level, and the second raw water pump is stopped when the water level in the water collection tank becomes equal to or lower than a third judgment water level that is lower than the first judgment water level.

6. The automatic start / stop of the first raw water pump and the second raw water pump in the normal operation mode is such that one is started when the water level in the water collection tank reaches a first judgment water level, and the other is started when the water level in the water collection tank reaches or exceeds a second judgment water level that is higher than the first judgment water level; In the first emergency operation mode, when the water level of the water collection tank becomes equal to or higher than the second judgment water level, the second raw water pump is started, and when the water level of the water collection tank becomes equal to or lower than a third judgment water level that is lower than the first judgment water level, the second raw water pump is stopped, A coal yard rainwater drainage facility as described in claim 2, characterized in that in the second emergency operation mode, after the second raw water pump is forcibly started manually, the second raw water pump is stopped when the water level in the water collection tank falls below a fourth judgment water level that is lower than the third judgment water level.

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