JP2017082694A - Pump control device, pump control method, and drainage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump control device, a pump control method and a drainage system which can follow an elevation of a water level and enhance safety.SOLUTION: A pump control device (12) controls a plurality of pumps which discharge water in a suction sump. Initial values of starting water levels and stopping water levels are set for respective pumps. The pump control device has: a water level determination section (52) which determines whether or not a water level in the suction sump is lowered to the stopping water level of any of the pumps; a starting water level management section (53) which updates the starting water levels in a manner that increases the same; and a pump stop control section (56) which stops the pumps. When any of the pumps does not start after a lapse of a predetermined second period since all the pumps are stopped, the starting water level management section (53) can reset the starting water levels of respective pumps to the initial values.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a pump control device, a pump control method, and a drainage system that control a plurality of pumps installed in a pump station where a water level varies.

  The pump station for river drainage is provided with a plurality of pumps, and the starting water level is set in advance so that the pumps are sequentially started as the water level in the suction tank 1 rises. When the water level reaches the starting water level, the pump is started sequentially, and the water in the suction water tank 1 is drained to the outside water river.

  The rate of increase of the water level in the suction tank 1 is different from that at the time of rain (for emergency use) and always, and generally the rate of increase at the time of rain is higher than the rate of increase at all times. For this reason, when the starting water level is the same at the time of rainfall and at the normal time, since the water level is more rapidly decreased at the normal time, the started pump may have to be stopped immediately.

  In addition, during rainfall, the rate of increase in water level is due to the increase in water due to local rainfall such as the recent guerrilla heavy rain and the increase due to relatively long-term rainfall due to typhoons and seasonal long rains that last for several days. Is different. Therefore, the timing and frequency of pump operation and stop vary depending on the situation.

  Furthermore, the timing and frequency of pump operation and stoppage vary depending on the regional characteristics of the rainy area. For example, even if the vicinity of the pump station is constant (no rain), if it is raining in the upstream (especially heavy rain), the influence is transmitted to the pump station, and the rapid water level rise may continue for a long time. In that case, the water level may continue to rise even if the pump is quickly additionally started and drained.

Especially in recent years, since rainfall tends to fall more locally and intensively in a short time, the inflow situation of the water that the pump station can cover is easy to change, and the frequency and operating load of the pump at the pump station are increasing. .
However, in the control of the number of pumps so far, there is a limit situation for draining following such a weather change.

  That is, when the rainfall situation fluctuates rapidly as in recent years, the pump frequently repeats operation and stoppage, and accordingly, the load on the driving machine and the motor that drives the pump increases. For example, if the load on the drive increases, there is a possibility of starting failure at the time of starting, and loss of the pump drainage function (drainage delay) occurs, and in the worst case, the weir of the inland river breaks and flooding damage There is a risk of spreading. In addition, if the load on the motor is increased, burning and burning may occur if the operation and stop are repeated more than the allowable start frequency, which may lead to a serious failure that is difficult to recover quickly.

  In recent years, not only the simple control of setting the pump start / stop water level in advance and starting or stopping from the pump that has reached the water level, but also based on the water level change rate and past rainfall information in advance. One that controls the number of pumps by correcting the set start / stop water level has been proposed.

  However, it is difficult to control the number of operating pumps stably without repeating excessive operation and stoppage of pumps according to seasonal and seasonal rainfall conditions and regional characteristics of the rainfall region throughout the year. In effect, effective reduction of the activation frequency has not been promoted.

JP 59-131784 A JP 7-259175 A JP-A-8-49287 JP-A-9-291888 JP 2000-265531 A JP 2000-355279 A

  The present invention has been made in view of such problems, and an object of the present invention is to provide a pump control device, a pump control method, and a drainage system that can follow a rise in water level and have high safety. .

According to one aspect of the present invention, there is provided a pump control device that controls a plurality of pumps for draining water from a suction water tank, wherein initial values of a start water level and a stop water level are set in each pump, A water level determination unit that determines whether or not the water level in the water tank has risen to the starting water level of any pump, and whether or not it has decreased to the stop water level of any pump, and which is the water level of the suction water tank A starting water level management unit that updates the starting water level so that the starting water level of the pump becomes higher when there is a history that the pump has stopped within the past first period, A pump start control unit for starting the pump when the water level of the suction water tank rises to the start water level of any pump and there is no history of the pump being stopped within the first period in the past; and the suction water tank of A pump stop control unit that stops the pump when the position has dropped to the stop water level of any pump, and after all the pumps have stopped, if any pump does not start, A pump control device is provided in which the starting water level management unit resets the starting water level of each pump to an initial value.
By updating the starting water level according to the pump stop history, the optimum starting water level can be obtained following the rise in the water level, and the pump activation frequency can be suppressed. Moreover, if the pumps are not started for a certain period after all the pumps are stopped, the optimum starting water level can be obtained quickly by resetting the starting water level to the initial value.

The starting water level management unit has a history that the water level of the suction water tank has risen to the starting water level of any of the pumps, and that the pump has stopped within the past first period, and the current water level rise rate When the water level is lower than the past water level rise rate, the starting water level is updated so that the starting water level of the pump becomes higher, and the pump starting control unit raises the water level of the suction water tank to the starting water level of any pump. The pump may be started when there is a history that the pump has stopped in the past first period and the current water level rise rate is higher than the past water level rise rate.
When the rate of increase of the water level is low, the start-up frequency of the pump can be suppressed by increasing the starting water level of the pump. In addition, when the rate of increase of the water level is high, the start delay of the pump can be prevented by starting the pump.

Moreover, according to another aspect of the present invention, there is provided a pump control device that controls a plurality of pumps for draining the water in the suction water tank, and initial values of a start water level and a stop water level are set in each pump. A water level determination unit that determines whether or not the water level of the suction water tank has risen to the starting water level of any pump, and whether or not the water level has decreased to the stop water level of any pump, and the water level of the suction water tank Rises to the start water level of any pump, the pump start control unit for starting the pump, and the water level of the suction water tank drops to the stop water level of any pump, and within the past third period If there is a history that the pump has been started, a stop water level management unit that updates the stop water level so that the stop water level of the pump becomes low, and the water level of the suction water tank decreases to the stop water level of any pump, and The pump stop control unit for stopping the pump when there is no history of the pump stopping in the third period, and after all the pumps stop, When the pump does not start, a pump control device is provided in which the stop water level management unit resets the stop water level of each pump to an initial value.
By updating the stop water level according to the start history of the pump, the optimum stop water level can be obtained following the decrease in the water level, and the pump start-up frequency can be suppressed. In addition, if the pumps are not started for a certain period after all the pumps are stopped, the stop water level is reset to the initial value, so that the optimum stop water level can be obtained quickly.

  According to another aspect of the present invention, a drainage system comprising a plurality of pumps for draining the water in the suction tank, a water level meter for measuring the water level in the suction tank, and the pump control device is an enemy bridge. The

  Further, according to another aspect of the present invention, there is provided a pump control method for controlling a plurality of pumps for draining water in a suction water tank, wherein initial values of a start water level and a stop water level are set for each pump. When the water level of the suction water tank rises to the starting water level of any pump and there is a history that the pump has stopped within the past first period, the starting water level is set so that the starting water level of the pump becomes high. Update, if the water level of the suction water tank rises to the starting water level of any pump and there is no history of the pump being stopped in the past first period, the pump is started, When the water level drops to the stop water level of any pump, the pump is stopped. After all the pumps are stopped, if no pump is started for a predetermined second period, the start water level of each pump is set to the initial value. Reset, pump control method is provided.

  By updating the starting water level according to the pump stop history, the optimum starting water level can be obtained following the rise in the water level, and the pump activation frequency can be suppressed. Moreover, if the pumps are not started for a certain period after all the pumps are stopped, the optimum starting water level can be obtained quickly by resetting the starting water level to the initial value.

Schematic diagram showing the drainage system Side view showing an example of a horizontal axis pump as an example of the pump P Sectional drawing which shows the internal structure of the horizontal-axis pump of FIG. Flow chart showing the procedure for starting the pump Flow chart showing the procedure for stopping the pump Block diagram showing a schematic configuration of the pump control device 12 The flowchart which shows an example of the processing operation of the pump control apparatus 12 in 1st Embodiment. The flowchart which shows an example of the processing operation of the pump control apparatus 12 in 2nd Embodiment. Diagram showing changes in water level The figure which shows the procedure at the time of starting the pump in 3rd Embodiment.

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

(First embodiment)
FIG. 1 is a schematic diagram showing a drainage system. This drainage system is provided in a pump station, and pumps up water in the suction tank 1 into which water from the inland river flows, and drains it into a discharge tank connected to the outside water river. The drainage system has a plurality of pumps P for draining, and a plurality of electric motors M that respectively drive these pumps P. In the example shown in FIG. 1, six pumps P and six electric motors M are provided. Each pump P is connected to an electric motor M through a speed reducer 4. In FIG. 1, only the first (No. 1) pump P is illustrated in detail, and the other pumps P are simplified.

  The drainage system includes a power receiving / distributing device 6 connected to the power system, a main transformer 7 for stepping down power from the power receiving / distributing device 6, and a plurality of devices connected to the main transformer 7 to control the operation of each electric motor M. Motor controller 8 (six in this example), on-site transformer 10 for further stepping down the output power of main transformer 7, and distribution control unit for distributing output power of on-site transformer 10 to various auxiliary devices described later 11 and a pump control device 12 (machine side pump operation device) for operating the pump P on the machine side.

  The electric motor control unit 8 is connected to each of the electric motors M, and includes a control panel that controls operations such as starting and stopping (normal stop, emergency stop at the time of failure, etc.) of the electric motors M.

  In addition to the electric motor M described above, the drainage system includes various incidental devices that operate upon receiving power supply. This accessory device includes, for example, a motor 21 that operates a discharge valve 20 disposed on the discharge side of the pump P, a full water detector 22 that detects whether or not the inside of the pump P is filled with water, A motor 24 that drives a vacuum pump 23 that discharges the air and introduces priming water, a motor 26 that drives a gear pump 25 that circulates lubricating oil in the speed reducer 4, a water fall detector 28 that detects water fall in the pump P, A water level meter 29 for measuring the water level in the suction water tank 1 is provided. These auxiliary devices are connected to the power distribution control unit 11 described above, and the operation of the auxiliary devices is controlled by the pump control device 12 described above.

  FIG. 2 is a side view showing an example of a horizontal axis pump which is an example of the pump P. The horizontal axis pump P drains the water in the suction tank 1 to the discharge tank 2 and is installed on the equipment installation floor 3 above the suction tank 1 in the pump station. On the equipment installation floor 3, the speed reducer 4 and the electric motor M (which may be an internal combustion engine such as a gas turbine or a diesel engine) shown in FIG. 1 are installed, and the horizontal axis pump P passes through the speed reducer 4. Driven by an electric motor M.

  A suction pipe 31 is connected to the suction side of the horizontal axis pump P, and a suction bell mouth 32 is connected to the lower end of the suction pipe 31. The suction pipe 31 opens below the water surface (suction water level) W1 of the suction water tank 1.

  On the other hand, a discharge pipe 34 is connected to the discharge side of the horizontal axis pump P via a discharge valve 33, and a discharge port of the discharge pipe 34 opens into the discharge water tank 2. A check valve 35 is provided at the discharge port of the discharge pipe 34.

  The horizontal axis pump P includes a discharge bowl 36, and suction pipes 31 and discharge pipes 34 are connected to both side surfaces thereof. Further, a pressure adjusting pipe 37 is connected above the discharge bowl 36 to adjust the pressure in the discharge bowl 36. That is, the discharge bowl 36 is evacuated by the vacuum pump 39 (driven by the electric motor 40) through the intake valve 38 provided in the pressure adjusting pipe 37 and released to the atmosphere through the vacuum breaker valve 41. . Further, the pressure adjustment pipe 37 is provided with a full water detector 42.

  FIG. 3 is a cross-sectional view showing an internal configuration of the horizontal axis pump of FIG. A suction casing 43 is connected to the suction side of the discharge bowl 36. A pump impeller 44 and a guide vane 45 are disposed in the discharge bowl 36, and the pump impeller 44 is attached to a main shaft 46 that is rotatably supported by an underwater bearing (not shown) disposed in the discharge bowl 36. . The main shaft 46 extends to the outside of the suction casing 43 via a shaft sealing mechanism 47. The pump impeller 44 is positioned above the suction water level (the water surface W1 of the suction water tank 1), and is a suction operation when the horizontal axis pump is operated.

  Hereinafter, an example in which the pump P is a horizontal axis pump will be described, but other types of pumps may be used.

  FIG. 4 is a flowchart showing a procedure for starting the pump. First, the intake valve 38 is opened (step S51) and the vacuum pump 39 is started (step S52). Thereby, the air in the discharge bowl 36 is exhausted, and the water in the suction water tank 1 is sucked into the discharge bowl 36 through the suction bell mouth 32, the suction pipe 31 and the suction casing 43.

  When the sucked water reaches the upper surface of the discharge bowl 36 and further reaches the full water detector 42, the full water detector 42 detects that the inside of the discharge bowl 36 has become full (step S53). Thereafter, the intake valve 38 is closed (step S54), the electric motor M is started (step S55), and the discharge valve 35 is opened (step S56). As a result, the pump impeller 44 rotates, and the water in the suction water tank 1 is continuously sucked into the suction bell mouth 32 and passes through the suction pipe 31, the suction casing 43, the discharge bowl 36 and the discharge pipe 34. Discharged. The above control is performed by a pump start control unit (described later) in the pump control device 12.

  FIG. 5 is a flowchart showing a procedure for stopping the pump. First, the discharge valve 33 is closed (step S61). Next, the motor M is stopped by turning off the circuit breaker (not shown) (step S62). Thereafter, the vacuum breaker valve 41 is opened (step S63), and the discharge bowl 36 is filled with air. As a result, the horizontal pump is stopped. Thereafter, the vacuum breaker valve 41 is closed (step S64). The above control is performed by a pump stop control unit (described later) in the pump control device 12.

  FIG. 6 is a block diagram illustrating a schematic configuration of the pump control device 12. This pump control device 12 controls a plurality of pumps P shown in FIG.

  The pump control device 12 includes a storage unit 51, a water level determination unit 52, a start water level management unit 53, a stop water level management unit 54, a pump start control unit 55, a pump stop control unit 56, and a timer 57. . At least a part of these units may be implemented by hardware, or may be implemented by software by executing a predetermined program by a processor (not shown).

  The storage unit 51 stores a start water level and a stop water level of the pump. The starting water level is determined for each pump, and is one of the conditions for starting the pump. The stop water level is determined for each pump, and is one of the conditions for stopping the pump. Initial values are set for the start water level and the stop water level, and the storage unit 51 stores the initial values. Further, the start water level and the stop water level can be updated, and the storage unit 51 also stores the updated start water level and stop water level. Further, the storage unit 51 stores the pump start / stop history, that is, when each pump is started / stopped.

  The water level determination unit 52 determines whether the water level in the suction water tank 1 has reached the start water level or the stop water level based on the measurement result of the water level gauge 29.

  The starting water level management unit 53 manages the starting water level. More specifically, the starting water level management unit 53 updates the starting water level based on the water level in the suction water tank 1 and the past pump stop history. Further, as one of the features of the present embodiment, the start water level management unit 53 resets the start water level to the initial value when the pumps are not started for a certain period after all the pumps are stopped.

  Similarly, the stop water level management unit 54 manages the stop water level. More specifically, the stop water level management unit 54 updates the stop water level based on the water level in the suction water tank 1 and the past pump stop history. Moreover, as one of the features of this embodiment, the stop water level management part 54 resets a stop water level to an initial value, when the pump is not started for a fixed period after all the pumps stop.

The pump start control unit 55 starts the pump according to the procedure described above with reference to FIG.
The pump stop control unit 56 stops the pump according to the procedure described above with reference to FIG.

  The timer 57 starts timing after all the pumps are stopped, and grasps the elapsed time from the stop of all the pumps. The measured time is used for controlling the timing at which the start water level management unit 53 and the stop water level management unit 54 reset the start water level and the stop water level, respectively.

  FIG. 7 is a flowchart illustrating an example of processing operation of the pump control device 12 according to the first embodiment. For convenience, it is assumed that the drainage system includes two pumps P1 and P2. Initially, the starting water levels SWL1, SWL2 of the pumps P1, P2 are both initial values SWL10, SWL20 (assuming SWL10 <SWL20), and the stop water levels STWL1, STWL2 of the pumps P1, P2 are both initial values STWL10, STWL20. (STWL10 <STWL20), and both pumps P1 and P2 are in a stopped state.

  First, the water level determination unit 52 determines whether the water level in the suction water tank 1 has risen to the starting water level SWL1 of the pump P1 based on the measurement data of the water level gauge 29 (step S1).

If it determines with having risen (YES of step S1), the starting water level management part 53 will refer to the memory | storage part 51, and will confirm the presence or absence of the log | history which the pump P1 stopped within the past fixed period (step S2). If there is a history of stoppage (YES in step S2), the starting water level management unit 53 updates the starting water level SWL1 to be higher (step S3). More specifically, the starting water level management unit 53 updates the starting water level SWL1 based on the following equation (1), and records the updated starting water level SWL1 in the storage unit 51.
SWL1 = SWL1 + UD1 (1)

  However, the updated starting water level SWL1 satisfies the relationship SWL1 <SWL2. Then, the pump P1 returns to step S1 without being started. Thereby, it can suppress that the pump P1 starts frequently.

  On the other hand, when there is no history of stopping (NO in step S2), the pump start control unit 55 starts the pump P1 without the start water level management unit 53 updating the start water level SWL1 (step S4). At this time, the pump start control unit 55 records in the storage unit 51 the time when the pump P1 is started. Thereby, only pump P1 will be in an operation state.

  Subsequently, the water level determination unit 52 determines whether or not the water level in the suction water tank 1 has increased to the starting water level SWL2 of the pump P2 and whether or not it has decreased to the stop water level STWL1 of the pump P1 (step S5). . First, the case where it rises to the starting water level SWL2 will be described.

If it is determined that it has risen (“rising to SWL2” in step S5), the starting water level management unit 53 refers to the storage unit 51 and confirms whether or not there is a history of the pump P2 being stopped within a certain past period ( Step S6). If there is a history of stoppage (YES in step S6), the starting water level management unit 53 updates the starting water level SWL2 to be higher (step S7). More specifically, the starting water level management unit 53 updates the starting water level SWL2 based on the following equation (2), and records the updated starting water level SWL2 in the storage unit 51.
SWL2 = SWL2 + UD2 (2)

  The increase amount UD1 in the equation (1) and the increase amount UD2 in the equation (2) may be the same or different. Thereafter, the pump P2 returns to step S5 without being started. Thereby, it can suppress that the pump P2 starts frequently.

  On the other hand, if there is no history of stoppage (NO in step S6), the start water level management unit 53 does not update the start water level SWL2, and the pump start control unit 55 starts the pump P2 (step S8). At this time, the pump start control unit 55 records in the storage unit 51 the time when the pump P2 is started. Thereby, both pumps P1 and P2 will be in an operating state.

  Thereafter, the water level determination unit 52 determines whether or not the water level in the suction water tank 1 has decreased to the stop water level STWL2 of the pump P2 (step S9). The stop water level STWL1 <STWL2.

If it determines with having fallen (YES of step S9), the stop water level management part 54 will refer the memory | storage part 51, and will confirm the presence or absence of the log | history which the pump P2 started within the past fixed period (step S10). When there is a history of starting (YES in step S10), the stop water level management unit 54 updates the stop water level STWL2 to be low (step S11). More specifically, the stop water level management unit 54 updates the stop water level STWL2 based on the following equation (3) and records it in the storage unit 51.
STWL2 = STWL2-WD2 (3)

  However, the updated stop water level STWL2 also satisfies the relationship STWL1 <STWL2. Thereafter, the pump P2 returns to step S9 without being stopped.

  On the other hand, when there is no history of starting (NO in step S10), the pump stop control unit 56 stops the pump P2 without the stop water level management unit 54 updating the stop water level STWL2 (step S12). At this time, the pump stop control unit 56 records the time point when the pump P2 is stopped in the storage unit 51. Thereby, only pump P1 will be in an operating state and it will return to Step S5.

When it is determined that the water level in the suction water tank 1 has decreased to the stop water level STWL1 of the pump P1 when only the pump P1 is in an operating state (“decrease to STWL1” in step S5), the stop water level management unit 54 With reference to the storage unit 51, it is confirmed whether or not there is a history of starting the pump P1 within a predetermined period in the past (step S13). When there is a history of starting (YES in step S13), the stop water level management unit 54 updates the stop water level STWL1 to be low (step S14). More specifically, the stop water level management unit 54 updates the stop water level STWL1 based on the following equation (4) and records it in the storage unit 51.
STWL1 = STWL1-WD1 (3)

  The reduction amount WD2 in equation (3) and the reduction amount WD2 in equation (4) may be the same or different. Thereafter, the pump P1 returns to step S5 without being stopped.

  On the other hand, when there is no history of stopping (NO in step S13), the pump stop control unit 56 stops the pump P1 without the stop water level management unit 54 updating the stop water level STWL1 (step S15). At this time, the pump stop control unit 56 records in the storage unit 51 the time when the pump P1 is stopped. Thereby, both pumps P1 and P2 are stopped.

  When both pumps P1, P2 are stopped, the timer 57 starts measuring time (step S16). Then, before the time measured by the timer 57 reaches a predetermined time T1 (NO in step S17), the pump P1 is started by satisfying the above-mentioned conditions of “YES” in step S1 and “NO” in S2. (YES in step S18), the timer 57 resets the time measurement (step S19). Then, the process returns to step S5.

  On the other hand, when pumping time P1 does not start (NO in step S18) and the measured time reaches time T1 (YES in step S17), starting water level management unit 53 sets starting water levels SWL1 and SWL2 to initial values SWL10 and SWL20, respectively. In addition to resetting, the stop water level management unit 54 resets the stop water levels STWL1 and STWL2 to the initial values STWL10 and STWL20, respectively (step S20). Then, the timer 57 resets the timekeeping time (step S21) and returns to step S1.

  The example in which two pumps P1 and P2 are provided has been described above, but there may be three or more pumps. When K pumps are provided, the initial value SWLn0 (n = 1 to K) of the start water level and the initial value STWLn0 of the stop water level are set higher as n increases. Further, the increase amount UD of the starting water level is preferably about 1/2 to 1/5 of the difference between the initial values of the starting water levels in the nth and (n + 1) th pumps, and is set to about 50 to 150 mm, for example. . The reduction amount WD of the stop water level is the same, and is preferably about 1/2 to 1/5 of the difference between the initial values of the stop water levels in the nth and (n + 1) th pumps.

Further, an upper limit value may be provided for the starting water level, and when the upper limit value is reached by updating the starting water level, the corresponding pump may be started immediately at that time. For example, the upper limit value of the starting water level in the nth pump is less than the initial value of the starting water level in the (n + 1) th pump. Further, the upper limit value of the starting water level in the K-th pump can be made equal to or lower than the allowable high water level HWL of the inner water level.
Only one of the start water level and the stop water level may be updated or reset.

  Thus, in the first embodiment, the start water level and the stop water level are updated according to the pump stop history and the start history. Thereby, the start water level and the stop water level are optimized according to the change in the water increase situation, and the frequency of start and stop of the pump can be reduced. Further, when the pumps are not started for a predetermined period after all the pumps are stopped, the start water level and the stop water level are reset to initial values. For this reason, if there is no increase in water for a predetermined time, the start water level and stop water level can be quickly updated by updating the start water level and stop water level from the initial values without depending on the past start water level and stop water level settings. Can be re-optimized.

  If one cycle starts from the first pump to the Kth pump and then stops sequentially, it depends on the surrounding rainfall conditions, etc., until the end of one cycle and the start of the next cycle. Changes in the amount of water inflow and the level of inflow water may change. In addition, when long-term operation is considered, for example, in the case where it becomes a season that depends on regional torrential rain after being optimally set as a measure for increasing water during the daily rainy season in the long rainy season, Water level fluctuations can change.

  In such a case, the optimum start water level and stop water level of the pump can be constructed by applying this embodiment.

(Second Embodiment)
In the first embodiment described above, the start water level and the stop water level are updated depending on whether there is a pump stop history within a certain past period. In contrast, in the second embodiment described below, the water level increase rate is stored in the storage unit 51 in addition to the stop history, and the update is performed in consideration of the water level increase rate. Hereinafter, a description will be given focusing on differences from the first embodiment.

  FIG. 8 is a flowchart illustrating an example of processing operation of the pump control device 12 according to the second embodiment. First, the water level determination unit 52 determines whether the water level in the suction water tank 1 has risen to the starting water level SWL1 of the pump P1 based on the measurement data of the water level gauge 29 (step S31).

  If it determines with having risen (YES of step S31), the starting water level management part 53 will refer to the memory | storage part 51, and will confirm the presence or absence of the log | history which the pump P1 stopped within the past fixed period (step S32).

  If there is a history of stopping, the starting water level management unit 53 further refers to the storage unit 51 and compares whether or not the current water level increase rate is greater than the past water level increase rate (step S33). The current water level increase rate is, for example, the water level increase rate in a predetermined period before the time when the water level reaches the current starting water level SWL1. The past water level increase rate is, for example, the water level increase rate in a predetermined period before the time when the water level reaches the previous start water level SWL1.

  FIG. 9 is a diagram schematically showing changes in the water level, where the vertical axis represents the water level and the horizontal axis represents time. As indicated by the alternate long and short dash line in the figure, when the current water level rise rate is not larger (NO in step S33 in FIG. 8), the starting water level management unit 53 updates the starting water level SWL1 based on the above equation (1). (Step S34). And the starting water level management part 53 records the water level raise rate at this time and the starting water level SWL1 after update in the memory | storage part 51. FIG.

  In this case, the pump start control unit 55 does not start the pump P1. This is because when the water level increase rate is low, the urgency of drainage is not high, and as soon as the pump P1 is started, the water level decreases and the pump P1 must be stopped within a short time.

  On the other hand, as shown by a two-dot chain line in FIG. 9, when the current water level rise rate is larger (YES in step S33 in FIG. 8), the start water level management unit 53 does not update the start water level SWL1, and the pump starts. The control unit 55 starts the pump P1 (step S35). Thereby, only pump P1 will be in an operation state. The starting water level management unit 53 records the water level increase rate at this time in the storage unit 51. When the water level increase rate is greater than a certain threshold, the starting water level management unit 53 may update the starting water level SWL1 to be low.

  Subsequently, the water level determination unit 52 determines whether or not the water level in the suction water tank 1 has increased to the starting water level SWL2 of the pump P2 and whether or not it has decreased to the stop water level STWL1 of the pump P1 (step S36). . First, the case where it rises to the starting water level SWL2 will be described.

  If it is determined that it has risen (“rise to SWL2” in step S36), the starting water level management unit 53 refers to the storage unit 51 and confirms whether or not there is a history of the pump P2 stopping within a certain period in the past ( Step S37).

  When there is a history of stoppage, the starting water level management unit 53 further refers to the storage unit 51 and compares whether or not the current water level increase rate is greater than the past water level increase rate (step S38). The current water level increase rate is, for example, the water level increase rate in a predetermined period before the time when the water level reaches the current starting water level SWL2. The past water level increase rate is, for example, the water level increase rate in a predetermined period before the time when the water level reaches the previous start water level SWL2.

  If the current water level rise rate is not larger (NO in step S38), the starting water level management unit 53 updates the starting water level SWL2 based on the above equation (2) (step S39). And the starting water level management part 53 records the water level raise rate at this time and the starting water level SWL2 after update in the memory | storage part 51. FIG.

  On the other hand, if the current water level increase rate is larger (YES in step S38), the pump start control unit 55 starts the pump P2 without the start water level management unit 53 updating the start water level SWL2 (step S40). The starting water level management unit 53 records the water level increase rate at this time in the storage unit 51. Thereby, both pumps P1 and P2 will be in an operating state. When the water level increase rate is greater than a certain threshold, the starting water level management unit 53 may update the starting water level SWL2 to be low.

  Thereafter, the water level determination unit 52 determines whether or not the water level in the suction water tank 1 has decreased to the stop water level STWL2 of the pump P2 (step S41). If it determines with having fallen (YES of step S41), the pump stop control part 56 will stop the pump P2 (step S42). The pump stop control unit 56 records the time point when the pump P2 is stopped in the storage unit 51. Thereby, only pump P1 will be in an operating state and it will return to Step S36. As in the first embodiment, the stop water level STWL2 may be updated in consideration of the past operation history.

  When it is determined that only the pump P1 is in the operating state, the water level in the suction tank 1 has decreased to the stop water level STWL1 of the pump P1 (“decrease to STWL1” in step S36), the pump stop control unit 56 P1 is stopped (step S43). The pump stop control unit 56 records the time point when the pump P1 is stopped in the storage unit 51. Thereby, both pumps P1 and P2 are stopped. As in the first embodiment, the stop water level STWL1 may be updated in consideration of the past operation history.

  When both pumps P1, P2 are stopped, the timer 57 starts measuring time (step S44). Then, before the time measured by the timer 57 reaches the predetermined time T1 (NO in step S45), the pump satisfies the conditions of “YES” in step S31 and “NO” in S32 or “YES” in S33. When P1 is started (YES in step S46), the timer 57 resets the time measurement (step S47). Then, the process returns to step S36.

On the other hand, when pumping time P1 does not start (NO in step S46) and the measured time reaches time T1 (YES in step S45), starting water level management unit 53 sets starting water levels SWL1 and SWL2 to initial values SWL10 and SWL20, respectively. Reset (step S48). When the stop water levels STWL1 and STWL2 are also updated, the stop water level management unit 54 resets the stop water levels STWL1 and STWL2 to the initial values STWL10 and STWL20, respectively. Then, the timer 57 resets the timekeeping time (step S49), and returns to step S31.
The example in which the two pumps P1 and P2 are provided has been described above. However, the number of pumps may be three or more, as in the first embodiment.

  As described above, in the second embodiment, when the starting water level of the pump is reached, even if there is a stop history within a certain past period, the pump is immediately started if the rising rate of the water level is large. Therefore, even when the rainfall situation is likely to fluctuate, a delay in starting the pump can be prevented and the reliability can be improved.

(Third embodiment)
The embodiment described below is characterized by the starting procedure of the pump P. In the case of the normal pump starting explained in FIG. 4 of the first embodiment, the pump is a horizontal axis pump, and it takes about 10 minutes until the inside of the discharge bowl 36 becomes full (step S53 in FIG. 4). There are many cases. That is, it takes a certain amount of time from the start of the pump start control to the completion thereof.

  For this reason, even if there is an urgent need to start the pump when it is determined that the pump should be started, it may not be necessary to start the pump due to a decrease in rainfall within a short period of time. For example, after the water level reaches the start water level, the water level may drop slightly and the water level may drop in the process of filling the discharge bowl 36 with water.

When the pump is started in such a situation, the drainage is performed more than necessary, and the water level drops rapidly in a short operation, and the pump must be stopped. Such an operation is not preferable because the frequency of starting and stopping the pump increases.
On the other hand, there is no drop in precipitation even when the inside of the discharge bowl 36 is full, and it is natural that the pump must be started immediately.

  Therefore, in the present embodiment, it is determined whether to continue or stop the pump according to the water level in the suction water tank 1 when the inside of the discharge bowl 36 becomes full.

  FIG. 10 is a diagram illustrating a procedure when starting the pump according to the third embodiment. Hereinafter, the difference from FIG. 4 will be mainly described. When it is detected by the full water detector 42 of FIG. 2 that the inside of the discharge bowl 36 is full (steps S51 to S53), the water level determination unit 52 determines whether or not the water level in the suction water tank 1 is still higher than the starting water level. Is determined (step S61). Specifically, when starting the pump P1 in step S4 in FIG. 7 (or step S35 in FIG. 8), the water level determination unit 52 compares the water level in the suction water tank 1 with the starting water level SWL1. When starting the pump P2 in step S8 in FIG. 7 (or step S40 in FIG. 8), the water level determination unit 52 compares the water level in the suction water tank 1 with the starting water level SWL2. If it is equal to or higher than the start water level, the pump start control unit 55 continues to start the pump (steps S54 to S56).

  When the water level drops and is lower than the starting water level when the inside of the discharge bowl 36 is full (NO in step S61), the pump start control unit 55 uses the internal timer (not shown) to measure the time. Start (step S62).

  If the water level again exceeds the start water level (NO in step S64) before the time measured by the timer reaches a predetermined time T2 (NO in step S64), the pump start control unit 55 continues to start the pump. (Steps S54 to S56).

  On the other hand, when the measured time reaches time T2 (YES in step S64) without the water level reaching the starting water level (NO in step S63), the pump start control unit 55 stops starting the pump (step S65). That is, the vacuum breaker valve 41 is opened to fill the discharge bowl 36 with air, and the pump is stopped. Then, if it is in the middle of step S4 of FIG. 7, it will return to step S1, and if it is in the middle of the same S8, it will return to step S5. If it is in the middle of step S35 in FIG. 8, the process returns to step S31, and if it is in the middle of S40, the process returns to step S36.

  Thus, in the third embodiment, the water level is checked again during the start control of the pump, that is, when the discharge bowl 36 of the horizontal shaft pump is full. Therefore, it is also suitable when the water level fluctuates in a short time due to changes in rainfall conditions. For example, when the water level drops in a short time, the frequency of starting and stopping the pump can be suppressed by not starting the pump. Further, when there is no fluctuation in the water level in a short time or when the water level continues to rise, the pump can be put into an operating state without delay in starting, and the reliability can be improved.

  In each of the embodiments described above, the start water level management unit 53 and the stop water level management unit 54 have an update mode for updating the start water level and the stop water level, and fixed values without updating the start water level and the stop water level. It is desirable to allow the operator to switch and set the fixed mode to be operated at an arbitrary timing. It is more desirable that the switching can be performed with a simple switch.

  For example, the fixed mode may be used in the season when the weather is calm, and the update mode may be used in the season when the weather is severely changed. Also, the fixed mode may be set at all times, and the update mode may be set in an emergency such as a typhoon or heavy rain. By doing so, the operator can leave the operation to the update mode when necessary, and can focus on monitoring equipment other than the pump, and can perform highly reliable crisis management. .

  In addition, the pump control device 12 records and saves operation data such as pump operation information (start and stop times, etc.) in the update mode, update history of the start water level and stop water level of each pump, and the number of updates. It is desirable to provide (not shown). The support unit preferably has a function of outputting the recorded operation data (for example, displaying on the display) and proposing an average value of the start water level and the stop water level as its initial value. Thus, by presenting the start water level and the stop water level based on the past operation results, it is possible to realize a facility with higher reliability and stability.

  Furthermore, you may make it have the determination function of the updated amount of the starting water level of each pump, and a stop water level. For example, the starting water level management unit 53 determines the update amount when updating the starting water level according to the output value of PI control or PID control based on the deviation between the initial value of the starting water level and the updated starting water level. May be. Specifically, using the output value of PI or PID as the predicted value obtained by integrating the operation start set value of each pump based on the deviation between the initial value of the starting water level and the current water level (measured water level), It is conceivable to apply a coefficient (gain value) in PI or PID output to the update amount of the starting water level of each pump. The same applies to the stop water level.

  Thus, if control using PI or PID is used, it would be possible to set the gain value, which has been difficult in the past, to a control value suitable for the equipment by adjusting and recording according to the actual situation. Therefore, the control becomes more accurate and reliable.

  Moreover, since the operating point (discharge amount) of the pump changes according to the water level difference (actual head) between the water tank level (inner water level) and the discharge water level (outer water level), it may affect water level fluctuations. Therefore, the adjustment range of the water level adjustment value may be determined by the operating point of the pump.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention should not be limited to the described embodiments, but should be the widest scope according to the technical idea defined by the claims.

As described above, according to one aspect of the present invention, the pump control device controls a plurality of pumps that drain the water in the suction water tank, and initial values of the start water level and the stop water level are set in each pump. A water level determination unit that determines whether or not the water level of the suction water tank has risen to the starting water level of any pump, and whether or not the water level has decreased to the stop water level of any pump, and the water level of the suction water tank Rises to the starting water level of one of the pumps, and if there is a history that the pump has stopped within the past first period, the starting water level management unit updates the starting water level so that the starting water level of the pump becomes higher And a pump start control unit that starts the pump when the water level of the suction water tank rises to the start water level of any pump and there is no history that the pump has stopped within the first period in the past, Above A pump stop control unit that stops the pump when the water level in the water tank drops to the stop water level of one of the pumps. After all the pumps have stopped, the pumps are started for a predetermined second period. If not, a pump control device is provided in which the starting water level management unit resets the starting water level of each pump to an initial value.
By updating the starting water level according to the pump stop history, the optimum starting water level can be obtained following the rise in the water level, and the pump activation frequency can be suppressed. Moreover, if the pumps are not started for a certain period after all the pumps are stopped, the optimum starting water level can be obtained quickly by resetting the starting water level to the initial value.

If the water level in the suction tank drops to the stop water level of any pump and there is a history of starting the pump within the past third period, the stop water level is updated so that the stop water level of the pump becomes low The pump stop control unit has a history that the water level of the suction water tank has dropped to the stop water level of any pump and the pump has stopped within the past third period. In this case, it is preferable that the stop water level management unit resets the stop water level of each pump to the initial value when none of the pumps is started during the second period after the pumps are stopped and all the pumps are stopped. .
By updating and resetting the stop water level in addition to the start water level, the optimum stop water level can be obtained quickly.

The starting water level management unit has a history that the water level of the suction water tank has risen to the starting water level of any of the pumps, and that the pump has stopped within the past first period, and the current water level rise rate When the water level is lower than the past water level rise rate, the starting water level is updated so that the starting water level of the pump becomes higher, and the pump starting control unit raises the water level of the suction water tank to the starting water level of any pump. The pump may be started when there is a history that the pump has stopped in the past first period and the current water level rise rate is higher than the past water level rise rate.
When the rate of increase of the water level is low, the start-up frequency of the pump can be suppressed by increasing the starting water level of the pump. In addition, when the rate of increase of the water level is high, the start delay of the pump can be prevented by starting the pump.

The starting water level management unit performs the starting water level so that the starting water level of the pump is lowered when the water level of the suction water tank rises to the starting water level of any pump and the current water level rise rate is higher than a predetermined value. The water level may be updated.
Thereby, a starting water level can be updated appropriately according to a water level rise rate.

The water level determination unit confirms the water level of the suction water tank during pump start control, and the pump start control unit continues the pump start control and confirms if the confirmed water level is equal to or higher than the start water level. If the water level is less than the starting water level, the pump continues to be started if the water level reaches the starting water level within a predetermined fourth period, and the water level reaches the starting water level within the fourth period. If not, pump start control may be stopped.
For example, the pump may be a horizontal axis pump having a discharge bowl, and the water level determination unit may check the water level when the discharge bowl becomes full.
As a result, when the water level drops in a short time, the pump is stopped from starting, so that the pump start-up frequency can be suppressed. In addition, when the water level does not fluctuate in a short time or when the water level continues to rise, the pump is started continuously, so that the pump can be put into an operating state without delay in starting, and reliability can be improved. .

The starting water level management unit can be set to an update mode or a fixed mode. When the update mode is set, the start water level is updated, and when the fixed mode is set, the start water level is not updated. Is desirable.
Thereby, it is possible to realize highly reliable crisis management by setting the update mode when necessary.

Record the change in water level, information on starting and stopping of the pump, and update history of the starting water level, output the recorded data, and start the initial starting water level based on the average value of the recorded starting water level It is desirable to provide a support unit that proposes values.
Thereby, it is possible to grasp appropriate initial values of the pump activation history and the starting water level.

The starting water level management unit determines an update amount when updating the starting water level according to an output value of PI control or PID control based on a deviation between the initial value of the starting water level and the updated starting water level. Also good.
Thereby, the update amount of a starting water level can be determined automatically and appropriately.

  Moreover, according to another aspect of the present invention, there is provided a drainage system comprising a plurality of pumps for draining the water in the suction tank, a water level meter for measuring the water level in the suction tank, and the pump control device. .

  Further, according to another aspect of the present invention, there is provided a pump control method for controlling a plurality of pumps for draining water in a suction water tank, wherein initial values of a start water level and a stop water level are set for each pump. When the water level of the suction water tank rises to the starting water level of any pump and there is a history that the pump has stopped within the past first period, the starting water level is set so that the starting water level of the pump becomes high. Update, if the water level of the suction water tank rises to the starting water level of any pump and there is no history of the pump being stopped in the past first period, the pump is started, When the water level drops to the stop water level of any pump, the pump is stopped. After all the pumps are stopped, if no pump is started for a predetermined second period, the start water level of each pump is set to the initial value. Reset, pump control method is provided.

DESCRIPTION OF SYMBOLS 1 Suction water tank 2 Discharge water tank 3 Equipment installation floor 4 Reduction gear 6 Power distribution device 7 Main transformer 8 Electric motor control part 10 In-house transformer 11 Power distribution control part 12 Machine side operation device 21 Motor 22 Discharge valve 23 Vacuum pump 24 Motor 25 Gear pump 26 Motor 28 Water fall detector 29 Water level gauge 31 Suction pipe 32 Suction bell mouth 33 Discharge gate valve 34 Discharge pipe 35 Check valve 36 Discharge bowl 37 Pressure adjustment pipe 38 Intake valve 39 Vacuum pump 40 Electric motor 41 Vacuum break valve 42 Full water detector 43 Suction casing 44 Pump impeller 45 Guide vane 46 Main shaft 47 Shaft seal mechanism 51 Storage unit 52 Water level determination unit 53 Start water level management unit 54 Stop water level management unit 55 Pump start control unit 56 Pump stop control unit 57 Timer M Electric motor P Pump

Claims (5)

A pump control device for controlling a plurality of pumps for draining water from a suction tank,
Each pump has initial values for the start water level and stop water level.
A water level determination unit that determines whether the water level of the suction water tank has risen to the starting water level of any pump, and whether the water level has dropped to the stop water level of any pump;
If the water level of the suction water tank rises to the starting water level of any pump and there is a history that the pump has stopped within the past first period, the starting water level is updated so that the starting water level of the pump becomes higher. Starting water level management department
A pump start control unit for starting the pump when the water level of the suction tank rises to the start water level of any pump and there is no history of the pump being stopped in the past first period;
When the water level of the suction water tank drops to the stop water level of any pump, a pump stop control unit that stops the pump, and
A pump control device in which the start water level management unit resets the start water level of each pump to an initial value when none of the pumps is started for a predetermined second period after all the pumps are stopped. The starting water level management unit
The water level of the suction tank rises to the starting water level of any pump, and
There is a history that the pump stopped in the past first period, and
If the current water level rise rate is lower than the past water level rise rate,
Update the starting water level so that the starting water level of the pump becomes high,
The pump start control unit
The water level of the suction tank rises to the starting water level of any pump, and
There is a history that the pump stopped in the past first period, and
If the current water level rise rate is higher than the past water level rise rate,
The pump control device according to claim 1, wherein the pump is started. A pump control device for controlling a plurality of pumps for draining water from a suction tank,
Each pump has initial values for the start water level and stop water level.
A water level determination unit that determines whether the water level of the suction water tank has risen to the starting water level of any pump, and whether the water level has dropped to the stop water level of any pump;
When the water level of the suction water tank rises to the start water level of any pump, a pump start control unit that starts the pump,
If the water level in the suction tank drops to the stop water level of any pump and there is a history of starting the pump within the past third period, the stop water level is updated so that the stop water level of the pump becomes low Stop water level management department to
A pump stop control unit for stopping the pump when the water level of the suction water tank is lowered to the stop water level of any pump and there is no history of the pump being stopped within the past third period; Prepared,
A pump control device in which the stop water level management unit resets the stop water level of each pump to an initial value when none of the pumps is started for a predetermined second period after all the pumps are stopped. A plurality of pumps for draining the water in the suction tank,
A water level meter for measuring the water level of the suction tank,
A drainage system comprising the pump control device according to any one of claims 1 to 3. A pump control method for controlling a plurality of pumps for draining water from a suction tank,
Each pump has initial values for the start water level and stop water level.
If the water level of the suction water tank rises to the starting water level of any pump and there is a history that the pump has stopped within the past first period, the starting water level is updated so that the starting water level of the pump becomes higher. And
If the water level of the suction tank rises to the starting water level of any pump and there is no history of the pump being stopped within the first period in the past, the pump is started,
If the water level in the suction tank drops to the stop water level of any pump, stop the pump,
A pump control method for resetting the starting water level of each pump to an initial value when none of the pumps is started for a predetermined second period after all the pumps are stopped.

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