JP2023016178A - Drainage pumping system - Google Patents

Abstract

To provide a drainage pumping system in which a drainage pump having a small discharge amount is placed in a first drainage pit so that the drainage pump that is started first discharges a suitable amount of water, and this drainage pump can be started first and reliably.SOLUTION: A drainage pump 2, a drainage pump 3, and a drainage pump 4 are placed in a drainage pit 1 that collects water such as water leaking from a water wheel of a power plant, and the drainage pump 4 has a smaller discharge amount per predetermined time than the drainage pumps 2 and 3 and is activated by a water level detection result by a water level detection device 20 different from a water level detection device 200 for the drainage pumps 2 and 3. The water level detection device 20 uses as a reference a water level shallower than a reference water level of the water level detection device 200, and the drainage pump 4 is activated when the water level reaches this reference, so that the drainage pump 4 is activated first among the drainage pumps 2, 3, and 4, and the water level detection device 20 is a float switch type to ensure reliable activation of the drainage pump 4.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a drainage pump installation for a power plant, such as a hydroelectric power plant.

2. Description of the Related Art Hydroelectric power plants have a first drainage pit for temporarily storing water such as water leakage from a water turbine at the bottom of the building of the power plant, for example, as disclosed in Patent Documents 1 and 2. There is, and the water is drained to the outside from this first drainage pit. In this way, when draining water from the first drainage pit to the outside, there are cases where oil is contained in the drainage water. A second drainage pit may be located and have an oil detection device within the second drainage pit.

On the other hand, as in Patent Document 2, the water temporarily stored in the first drainage pit is discharged using, for example, two drainage pumps arranged in the first drainage pit. may occur. As an example of using two such drain pumps, one may be used as a regular drain pump and the other as a standby drain pump. In this case, when the water level detection device arranged in the first drainage pit detects that the water level in the drainage pit has reached a predetermined standard, the water level detection device sends a signal to the motor of the regular drainage pump through a predetermined path. is sent to activate the regular drain pump to drain the water in the first drain pit. In addition, the water level in the first drainage pit has risen further, and the water level in the first drainage pit has reached the second standard. When it is detected by the water level detection device, a signal is sent from the water level detection device to the motor of the standby drainage pump through a predetermined path to start the standby drainage pump, and the water in the first drainage pit to discharge.

Japanese Unexamined Patent Application Publication No. 2015-20086 JP 2007-162659 A

However, since the actual leakage amount of the power plant and the discharge amount of the drainage pump design do not match, if the discharge amount of the drainage pump per predetermined time is large, a large amount of water is sent to the second drainage pit. The water surface of the second drainage pit is inadvertently agitated by the water discharged from the second drainage pit, causing malfunction of the oil detection device floating on the water surface of the drainage accumulated in the second drainage pit.

A wire-type float 200 as shown in FIG. 6 is generally used as a device for detecting the water level of the drainage pit. As shown in FIG. 6, the wire type float 200 includes, for example, a float 201, a cylinder 201a for surrounding the float 201, a wire 202, a drum 203 for winding the wire 202, and a mechanism 204 for setting the water level. and a weight 205 . However, in the wire type float 200 as shown in FIG. 6, the reliable water level detection capability may be questioned because the wire 202 in the low water level range, which is always used, tends to become twisted. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and has a drainage pump that discharges a smaller amount of water per predetermined time than other drainage pumps so that the drainage pump that is started first discharges a suitable amount of water. A main object of the present invention is to provide a drainage pump facility in which a pump is arranged in a first drainage pit and the arranged drainage pump can be started first and surely.

In order to achieve the above object, the drainage pump facility of the present invention is provided between a first drainage pit that stores water from equipment of a power plant and a drainage route from the first drainage pit to a drainage destination. a second drainage pit for collecting water from said first drainage pit and said first drainage pit for sending water from said first drainage pit to said second drainage pit a first drainage pump; a second drainage pump disposed in the first drainage pit for sending water from the first drainage pit to the second drainage pit; a first water level detection for detecting that the water level of the water accumulated in the first drainage pit has reached a predetermined standard in the drainage pump and prompting the first and second drainage pumps to start up; and an oil detection device that is installed in the second drainage pit and detects the oil content of the water accumulated in the second drainage pit, wherein from the first drainage pit to the second as a pump for sending water to the drainage pit, a third drainage having a smaller discharge amount per predetermined time to the second drainage pit than the first and second drainage pumps to the first drainage pit A pump is further arranged, and the third drainage pump is started before the first and second drainage pumps. The equipment of the power plant is, for example, a water turbine in the case of a hydroelectric power plant. The first drainage pit is, for example, a drainage pit located at the bottom of a power plant building. The second drainage pit is, for example, an outdoor drainage pit. Drainage destinations include, for example, rivers, ponds, lakes, and the sea.

In this way, the third drainage pump is provided as a pump for sending water from the first drainage pit to the second drainage pit, and the discharge amount per predetermined time is smaller than that of the other two drainage pumps. By activating the third drainage pump first, it is possible to suppress the discharge amount per predetermined time from the first drainage pit to the second drainage pit at the initial stage of drainage. Since the water surface of the second drainage pit is less likely to be accidentally agitated, malfunction of the oil detection device floating on the water surface of the second drainage pit does not occur.

Then, the drainage pump equipment of the present invention has a second water level detection device different from the first water level detection device in the first drainage pit, and the second water level detection device is connected to the first drainage Detecting that the water level in the pit has reached a second reference shallower than the predetermined reference used in the first water level detection device, and prompting the third drainage pump to start. It is characterized by being The first water level detection device is, for example, a wire type float.

In this way, as a water level detection device for detecting that the water level in the first drainage pit has reached a predetermined standard and prompting the third drainage pump to start, the water level detection device is different from the first water level detection device By making it possible to use the second water level detection device, it becomes possible to increase the degree of freedom of the device to be selected as the second water level detection device.

Further, in the drainage pump facility of the present invention, the second water level detection device is provided with a float at the tip of a linear member suspended from above the first drainage pit toward the pooled water. , the displacement of the float detects that the water accumulated in the first drainage pit has reached the second standard, and prompts the third drainage pump to start. Characterized by The second water level detection device is, for example, a suspended float switch.

Thus, by using a device such as a hanging float switch as the second water level detection device, the reliability of the detection device can be improved compared to the case of using a wire type float. of the three drainage pumps to be started first.

As described above, according to the drainage pump facility of the present invention, as the pump for sending water from the first drainage pit to the second drainage pit, the water is pumped more than the other two drainage pumps for a predetermined time. A third drainage pump having a small discharge amount per unit is provided, and the third drainage pump is started first, so that the flow from the first drainage pit to the second drainage pit at the initial stage of drainage is achieved. Since it is possible to suppress the discharge amount per predetermined time, the water surface of the second drainage pit is less likely to be accidentally agitated, so the malfunction of the oil detection device floating on the water surface of the second drainage pit can be prevented from occurring.

In particular, according to the drainage pump facility of the invention according to claim 2, a water level detection device for detecting that the water level in the first drainage pit has reached a predetermined standard and prompting the third drainage pump to start. As a result, it is possible to use the second water level detection device different from the first water level detection device, so that the degree of freedom of the device to be selected as the second water level detection device can be increased.

In particular, according to the drainage pump equipment of the invention according to claim 3, the water level detection device of the third drainage pump is suspended from above the first drainage pit by making it a suspension type float switch type. If it is possible to secure even a place where it can be installed, it will be possible to install it without using a dedicated hole or tool. Moreover, when used as a second water level detection device, for example, as a wire type float, it is possible to avoid the tendency of the wire to twist, etc., so that the reliability of the water level detection device can be enhanced. .

FIG. 1 is a schematic diagram showing an example of the configuration of a hydroelectric power plant and an example of the configuration of drainage pump equipment of the hydroelectric power plant. FIG. 2 is an enlarged view showing a first drainage pit in the drainage pump facility and equipment such as a drainage pump installed around the first drainage pit. FIG. 3 is a control circuit diagram for controlling three drainage pumps. FIG. 4 is a perspective view of a suspended float switch forming a water level detection device for a third drain pump. 5A and 5B show the operation of the suspended float switch, in which (a) shows the state when the switch is turned on, and (b) shows the state when the switch is turned off. It is a figure which shows the wire type float which makes the water level detection apparatus for 1st, 2nd drainage pumps.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, a schematic configuration example of a hydroelectric power plant to which the present invention is applicable, and drainage pump equipment, for example, a drainage pit 1 at the deepest position of the hydroelectric power plant and a drainage arranged outdoors An example of an embodiment with pits 9 is shown.

As shown in FIG. 1, a hydroelectric power station has, for example, a water turbine generator 100 equipped with equipment such as a generator and a water turbine. Connected and configured. The water turbine generator 100 is installed on the floor surface 101a of the water turbine chamber 101 in this embodiment.

In this embodiment, as shown in FIG. 1, there is a space 103 below the water turbine chamber 101, and a pipe 104 extending from the bottom of the water turbine generator 100 into the space 103 passes through the space 103 to drain water. By being connected to the pit 1, water such as water leakage from the water turbine of the water turbine generator 100 flows into the drainage pit 1. - 特許庁Motors 5a, 5b, and 5c for driving drainage pumps 2, 3, and 4 described below are installed on a top plate 1b positioned above the drainage pit 1 of the water turbine chamber 101 and connected to the floor surface 101a. there is These motors 5a, 5b, 5c are controlled by control signals S1, S2, S2, S1, S2, S1, S2, S1, S2, S1, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2, S2. It is controlled by S3.

As shown in FIGS. 1 and 2, the drainage pit 1 is equipped with a drainage pump 2, a drainage pump 2, and a drainage pump 2 for sending (discharging) water accumulated in the drainage pit 1 to a drainage pit 9 outside the hydroelectric power plant. A drainage pump 3 and a drainage pump 4 to be described later are provided.

In this embodiment, the drainage pump 2 is used as a regular drainage pump, and the drainage pump 3 is used as a standby drainage pump. When it is detected that the water level of the drainage pit 1 detected by the water level detection device 200 shown in FIG. However, when it is detected that the water level in the drainage pit 1 has fallen below the reference 4 (described below), a control signal S1 is sent to the motor 5a to stop the drainage pump 2. Furthermore, when it is detected that the water level of the drainage pit 1 detected by the water level detection device 200 has reached the reference 2 (described below), a control signal S2 is sent to the motor 5b to start the drainage pump 3, When it is detected that the water level in the drainage pit 1 has fallen below the reference 4, a control signal S2 is sent to the motor 5b to stop the drainage pump 3.

Water pumped up from the drainage pit 1 by the operation of the drainage pump 2 is discharged to the drainage pit 9 through the drainage path 80 in this embodiment. In this embodiment, the water pumped up from the drainage pit 1 by the operation of the drainage pump 3 is discharged to the drainage pit 9 after joining the drainage path 81 to the drainage path 80 . A plurality of valves 80a and 80b are arranged in the drainage path 80 to prevent backflow during inspection of the drainage pump 2, for example. A plurality of valves 81a, 81b are arranged.

The water level detection device 200 is a wire type float in this embodiment. That is, the water level detection device 200 has a weight 205 and a drum 203 on a main body fixed to the top plate 1b of the drainage pit 1, as shown in FIG. A wire 202 is wound around the drum 203 , and a float 201 is fixed to the tip of the wire 202 to float on the surface of the water accumulated in the drainage pit 1 .

The float 201 moves up and down by rotating the drum 203 in conjunction with the vertical fluctuation of the water surface of the water accumulated in the drainage pit 1 and winding up or pulling out the wire 202 . Around the float 201, a cylinder 201a surrounding the float 201 is arranged with a length from the bottom surface 1a of the drainage pit 1 to the vicinity of the lower surface 1c of the top plate 1b. The water level detection device 200 is connected to the drain pump control circuit 60 in the switchboard 6 .

As a result, when the water level detection device 200 detects that the water level in the drainage pit 1 has reached a predetermined reference (references 1 and 2 described above) due to the vertical movement of the float 201, as shown in FIG. A signal S4 is sent to the control circuit 60 of the pump.

The drainage pump 4 has a smaller discharge amount per predetermined time than the drainage pumps 2 and 3 described above, and may be additionally arranged later with respect to the existing drainage pumps 2 and 3 . When the water level of the drainage pit 1 detected by the water level detection device 20 different from the water level detection device 200 described above reaches the reference 3 (described below), a control signal S3 is sent to the motor 5c. When the drainage pump 4 is activated and it is detected that the water level in the drainage pit 1 has fallen below the reference 4, a control signal S3 is sent to the motor 5c to stop the drainage pump 3.

Water pumped up from the drainage pit 1 by the operation of the drainage pump 4 is discharged to the drainage pit 9 through a drainage path 82 completely independent of the drainage paths 80 and 81 in this embodiment. A plurality of valves 82a and 82b are arranged in the drainage path 82, for example, to prevent backflow during inspection of the drainage pump 4, for example.

The water level sensing device 20 is a suspended float switch in this embodiment. That is, as shown in FIG. 4, the water level detection device 20 includes, for example, a cable 24 whose one end is fixed to the top plate 1b of the drainage pit 1 and extends from the gap of the top plate 1b toward the bottom surface 1a of the drainage bit 1; It comprises a support 23 supporting the other end of a cable 24, a cable 22 extending from the support 23, and a float switch 21 provided at the end of the cable 22 in the extension direction. The length of the cable 24 suspended from the top plate 1 b can be adjusted to an appropriate dimension, and the end of the cable 24 opposite to the support 23 is connected to the control circuit 60 of the switchboard 6 .

As shown in FIG. 5, the float switch 21 of the water level detection device 20 contains a movable weight 21a. The switch is turned on and off by moving to the side or moving to the side opposite to the connection side with the cable 24 . That is, the float switch 21 itself, in which the movable weight 21a is housed, functions as a switch. A signal S5 (shown in FIG. 2) indicating that is transmitted to the drainage pump control circuit 60 stored in the control panel 6, and a control signal S3 is transmitted from the drainage pump control circuit 60 to the motor 5c to start the motor 5c. . As a result, the drainage pump 4 is also activated, and the water accumulated in the drainage pit 1 is drained to the drainage pit 9 through the drainage path 82 by the drainage pump 4. - 特許庁In this embodiment, the criterion 3 for activating the drainage pump 4 is greater than the criterion 1 for activating the drainage pump 2 and the criterion 2 for activating the drainage pump 3. is set to a shallow water level, and the details of the criteria will be described later.

A more detailed operation of the water level detection device 20, which is a suspended float switch, will be described with reference to FIG.

FIG. 5(a) shows how the float switch 21 of the water level detection device 20 is turned on from the off state. That is, at the first position A indicated by the solid line, the float switch 21 is floating on the water surface 25 where the water level from the bottom surface 1a of the drainage pit 1 is at the lower water level H1, and the cable 22 is below the support 23. Hanging down. In this case, the movable weight 21a is located at the end (hereinafter referred to as the tip) of the float switch 21 opposite to the position where the cable 22 is attached, and the switch is turned off. When the water level in the drainage pit 1 rises above the lower limit water level H1, the float switch 21 floating on the water surface also rises as the water level rises, and first reaches a position below the support 23. , to the position of B indicated by the dashed line. Next, as the water level in the drainage pit 1 further rises, the float switch 21 rises to the position C indicated by the dashed line, which is substantially the same position as the support 23, and furthermore The water surface 26 at which the water level from the bottom surface 1a of the drainage pit 1 set as the reference 3 is at the upper limit water level H2. It is the position of F indicated by the dashed-dotted line. When the float switch 21 rises in this manner, the relationship between the support 23 and the wire 22 causes the float switch 21 to be displaced so that the tip faces upward in the range from position C to position F. As a result, , F, the front end of the float switch 21 is directly upward, and the movable weight 21a in the float switch 21 is completely moved to the connection side with the cable 22, and the magnet (not shown) in the float switch 21 and the The switch is turned on by being magnetized by contact.

FIG. 5B shows how the float switch 21 of the water level detection device 20 is turned off from the on state. That is, when the float switch 21 floats on the water surface 26 where the water level from the bottom surface 1a of the drainage pit 1 is the upper limit water level H2, the tip of the float switch 21 faces straight up at the initial position A indicated by the solid line. , the movable weight 21a in the float switch 21 is on the connection side with the cable 22 (opposite to the tip), and the switch is in the ON state. Even if the water level in the drainage pit 1 falls below the upper limit water level H2, the float switch 21 is positioned above the support 23 at a position B indicated by a broken line, or at a position B indicated by a dashed line at approximately the same position as the support 23. In the case of position C, in this embodiment, the tip of the float switch 21 remains pointing straight up, so the movable weight 21a in the float switch 21 does not change and remains on the side connected to the cable 22. (on the side opposite to the tip), and the switch is kept in the ON state. When the water level in the drainage pit 1 further drops and the float switch 21 is at least at the position D indicated by the two-dot chain line, which is lower than the support 23, the relationship between the support 23 and the cable 22 causes the float switch 21 to move. The tip begins to point downwards. Then, the water level in the drainage pit 1 further drops, and the float switch 21 moves from the position D to the position E indicated by the broken line, and the water level from the bottom surface 1a of the drainage pit 1 set as the reference 4 reaches the lower limit water level H1. When it floats on the water surface 25 at the position F indicated by the dashed line, the tip of the float switch 21 faces straight down. As a result, the movable weight 21a completely moves to the tip side of the float switch 21 and is separated from the magnet, so that the switch is turned off.

From the drainage pit 9 arranged outside the hydroelectric power plant, water flows to the outside (for example, rivers, the sea, etc.) as indicated by the arrows in FIG. Along with this, in order to detect whether oil is contained in the water flowing outside, in this embodiment, as shown in FIGS. 1 and 2, an oil detection device 8 floats on the surface of the water. . Along with this, in this embodiment, an oil removing device (not shown) for removing the oil detected by the oil detecting device 8 is installed in the drain pit 9, for example. Of course, the oil removal device may be installed in the drainage pit 1 or may be installed in both the drainage pits 1 and 9 .

Next, an example of the drainage pump control circuit 60 stored in the control panel 6 will be described with reference to FIG.

A control circuit 60 for each of the drain pumps 2, 3, 4 is located between power lines P, N, which are control buses. Circuits 61, 62, and 63 for controlling the drain pump 4, the drain pump 3, and the drain pump 2 are shown in order from the right in FIG. The control circuit 61 of the drainage pump 4 is connected to the motor 5c, the control circuit 62 of the drainage pump 3 is connected to the motor 5b, and the control circuit 62 of the drainage pump 2 is connected to the motor 5a.

A circuit 61 for controlling the drainage pump 4 on the right side of FIG. 3 is paired with an automatic control circuit 61a and a manual control circuit 61b. When testing the drainage pump 4, the manual switch 613 of the control circuit 61 of the drainage pump to be tested is turned ON, and the push button switch 614 is pressed to operate the relay 617, and the relay contact 614a is interlocked. is turned ON, and the drainage pump 4 is continuously operated. By pressing the b-contact push button switch 615, the drainage pump 4 is stopped, and the drainage pump 4 can be tested manually, but in the present invention, further explanation of the manual operation is omitted.

The automatic control circuit 61a comprises an automatic switch 610, terminals 611a, 611b, 611c, a limit switch 612, a relay contact 612a, a b-contact oil leakage detection switch 616, a relay 617, and a b-contact drainage pump failure detection switch 618. there is The limit switch 612 is connected from the water level detector (wire type float) 200 and constitutes an automatic control circuit similar to the drain pump 3 described later. The water level detection device (suspended float switch) 20 is connected so that the limit switch 612 and the automatic control circuit of the relay contact 612a are not used, so the terminals 611a and 611b are directly connected by wiring. ing.

When the water level 1d in the drainage pit 1 rises and reaches the set standard 3 (for example, the water level 1.2 m from the bottom surface 1a of the drainage pit 1, which is the upper limit water level H2), the float switch of the water level detection device 20 is turned on. 21 is turned ON, a signal S5 to the effect that it has been turned ON is sent to the control circuit 60 (61), the relay 617 is operated, and the motor 5c is operated by this conduction, thereby starting the drainage pump 4, Drainage is done. When the water level 1d in the drainage pit 1 drops and reaches a reference 4 (for example, the water level of 60 cm from the bottom surface 1a of the drainage pit 1), the drainage pump 4 stops. The automatic switch 610 is normally ON, and when the water level in the drainage pit 1 reaches a set level, the drainage pump 4 automatically starts or stops.

The circuit 63 for controlling the drain pump 2 shown on the left side of FIG. 3 is paired with an automatic control circuit 63a and a manual control circuit 63b. When testing the drainage pump 2, the manual switch 634 of the control circuit 63 of the drainage pump to be tested is turned ON, and the push button switch 635 is pressed to operate the relay 638, and the relay contact 635a is interlocked. is turned ON, and the drainage pump 2 is continuously operated. By pressing the b-contact push button switch 636, the drainage pump 2 is stopped, and the drainage pump 2 can be tested manually, but in the present invention, further explanation of the manual operation is omitted.

The automatic control circuit 63a includes an automatic switch 630, terminals 631a, 631b, 631c, a limit switch 632, a relay contact 632a, a limit switch 633, a b-contact oil leakage detection switch 637, a relay 638, and a b-contact drainage pump failure detection switch 639. consists of The limit switches 632 and 633 are connected from the water level detector (wire type float) 200 .

When the water level in the drainage pit 1 reaches the set reference 4 (for example, the water level of 60 cm from the bottom surface 1c of the drainage pit 1) of the set reference 1, the limit switch 633 is turned on, and the drainage pump 2 enters the standby state. . When the water level further rises and reaches the set standard 1 (for example, the water level of 1.4 m from the bottom surface 1a of the drainage pit 1), the water level detection device (wire type float) 200 detects that the water level has reached the standard 1. A signal S4 to that effect is sent to the control circuit 60 (63), the limit switch 632 and the relay 638 are operated, the relay contact 632a is interlocked and turned ON, and the motor 5a is operated by this electrical connection, so that the drainage pump 2 starts and drains water. When the water level in the drainage pit 1 drops and reaches the reference 4 (for example, the water level of 60 cm from the bottom surface 1a of the drainage pit 1), the limit switch 633 is turned off and the drainage pump 2 is stopped. The automatic switch 630 is normally ON, and when the water in the drainage pit 1 reaches a set standard, the drainage pump 2 is automatically started or stopped.

The circuit 62 for controlling the drainage pump 3 shown in the center of FIG. 3 is paired with an automatic control circuit 62a and a manual control circuit 62b. When testing the drainage pump 3, the manual switch 624 of the control circuit 62 of the drainage pump to be tested is turned ON, and the push button switch 625 is pressed to operate the relay 628, and the relay contact 625a is interlocked. is turned on, and the drainage pump 3 is continuously operated. By pressing the b-contact push button switch 626, the drainage pump 3 is stopped, and the drainage pump 3 can be tested manually, but in the present invention, further explanation of the manual operation is omitted.

Similar to the automatic control circuit 63a of the circuit 63 controlling the drainage pump 2, the automatic control circuit 62a of the circuit 62 controlling the drainage pump 3 also includes an automatic switch 620, terminals 621a, 621b, 621c, a limit switch 622, a relay contact 622a and a limit switch. It is composed of a switch 623, an oil leakage detection switch 627 with a b-contact, a relay 628, and a drainage pump failure detection switch 629 with a b-contact. The limit switches 622 and 623 are connected from the water level detector (wire type float) 200 .

When the water level in the drainage pit 1 reaches the reference value 4 (for example, the water level of 60 cm from the bottom surface 1a of the drainage pit 1) set before the reference 2, the limit switch 623 is turned on, and the drainage pump 3 is put into a standby state. Become. When the water level further rises and reaches the set standard 2 (for example, the water level of 1.6 m from the bottom surface 1a of the drainage pit 1), the water level detection device (wire type float) 200 detects that the water level has reached the standard 2. A signal to that effect is sent to the drainage pump control circuit 60 (62), the limit switch 622 and the relay 628 are operated, the relay contact 622a is interlocked and turned ON, and the motor 5b is operated by this conduction, and the drainage pump is operated. 3 is activated and water is drained. When the water level in the drainage pit 1 drops and reaches the reference 4 (for example, the water level of 60 cm from the bottom surface 1a of the drainage pit 1), the limit switch 623 is turned off and the drainage pump 3 is stopped. The automatic switch 620 is normally ON, and when the water in the drainage pit 1 reaches a set standard, the drainage pump 3 automatically starts or stops.

In addition, up to the standard 4 (for example, the water level of 60 cm from the bottom surface 1a of the drainage pit 1) set as the lower limit water level (for example, the lower limit water level H1 in FIG. 5) from the bottom surface 1b of the drainage pit 1 of the drainage pumps 2, 3, and 4 When it drops, the control circuit 60 causes the limit switches 633, 623 of the circuits 61, 62, 63, which had been conducting, to stop conducting, and accordingly the relays 617, 638, 628 also stop, and the drainage pumps 2, 3 Stop.

By the control circuit 60 (61, 62, 63) described above, the drainage pump 4 is started when the water level reaches 1.2 m from the bottom surface 1a of the drainage pit 1, and the drainage pump 2 is operated in the drainage pit 1. It is started when the water level reaches 1.4 m from the bottom surface 1a, and the drainage pump 3 is started when the water level reaches 1.6 m from the bottom surface 1a of the drainage pit 1, so the drainage pump 4 is drained. Pumps 2, 3, and 4 can now be activated first. Along with this, by using a drainage pump with a smaller discharge amount per predetermined time than the drainage pumps 2 and 3 as the drainage pump 3 and using a float switch as the water level detection device 20 for prompting the activation of the drainage pump 3, When discharging water from the drainage pit 1 to the drainage pit 9 by the drainage pump 3 which is started first and surely, the water surface of the drainage pit 9 is inadvertently agitated to prevent the oil detection device 8 from malfunctioning. It could be prevented.

In the present invention, three drainage pumps (drainage pumps 2, 3, and 4) have been described, but the number of drainage pumps is not limited to three as long as the drainage pump 4, which is activated first, is reliably activated.

Moreover, the specific standards 1 to 5 of the water level of the waste water can be appropriately changed to numerical values according to the situation, the environment, etc., and are not limited to the numerical values shown in the present invention.

Furthermore, in the present invention, an example of using a suspended float switch as the water level detection device 200 was shown, but if it is possible to obtain the same effect as the present invention, a water level detection device with a different structure may be used. Also good.

1 drainage pit (first drainage pit)
2 drainage pump (first drainage pump)
3 drainage pump (second drainage pump)
4 Drainage pump (third drainage pump)
60 Drainage pump control circuit 8 Oil detection device 9 Drainage pit (second drainage pit)
20 Hanging float switch (second water level detector)
80 Drainage route 81 Drainage route 82 Drainage route 200 Wire type float (first water level detector)

Claims (3)

A first drainage pit for storing water from equipment of the power plant and a second drainage path for storing water from the first drainage pit, which is disposed between the first drainage pit and a drainage destination. a drainage pit; a first drainage pump disposed in said first drainage pit for sending water from said first drainage pit to said second drainage pit; a second drainage pump arranged in the first drainage pit for sending water to the second drainage pit; A first water level detection device for detecting that the has reached a predetermined standard and prompting the first and second drainage pumps to start, and the second water level detection device installed in the second drainage pit In the drainage pump facility having an oil detection device that detects the oil content of the water accumulated in the drainage pit of
As a pump for sending water from the first drainage pit to the second drainage pit, a predetermined time to the second drainage pit than the first and second drainage pumps to the first drainage pit A drainage pump facility, further comprising a third drainage pump having a small discharge amount per unit, wherein the third drainage pump is activated before the first and second drainage pumps. A second water level detection device different from the first water level detection device is provided in the first drainage pit, and the second water level detection device detects whether the water level in the first drainage pit is equal to the first water level. It is for detecting that the water depth has reached a second standard shallower than the predetermined standard used by the detection device, and for urging the activation of the third drainage pump. 1. Drainage pump equipment according to 1. The second water level detection device is provided with a float at the tip of a linear member suspended from above the first drainage pit toward the pooled water, and the first drainage pit is detected by displacement of the float. 3. The drainage pump facility according to claim 2, characterized in that it is for detecting that the water accumulated in the water reaches the second standard and prompting the activation of the third drainage pump. .

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