JP5213295B2 - Method and apparatus for predicting outflow amount outside water tank during operation of feed pump - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

  The present invention relates to a method and apparatus for predicting the outflow amount to the outside of a water tank during operation of the water supply pump for accurately predicting the outflow amount of water flowing out of the water tank such as a water supply pump facility mainly using a water tank. Is.

Conventional technology and its problems

  Conventionally, in a water supply pump facility that starts water supply at the upper limit water level and completes water supply at the lower limit water level, the outflow amount to the outside of the water tank per unit time calculated from the time to reach the lower limit water level from the upper limit water level when the pump is stopped is Calculate the total outflow assuming that the pump will continue to operate. In addition, the upper limit water level arrival time from the start of pump operation is predicted based on the three factors of the outflow amount to the outside of the tank, the volume between the upper and lower limit water levels in the tank, and the pump rated discharge amount (setting value). A decrease in pump discharge due to an air lock or suction blockage is determined based on the actual water level at the expected arrival time.

Problems to be solved

  However, the above prior art assumes that the amount of inflow during the pump stop to the outside of the aquarium continues even during the pump operation assuming a facility where the pump operation time is shorter than the pump stop time. In the feed water pump facility, the outflow amount to the outside of the water tank may fluctuate even during the pump operation. Therefore, the longer the pump operation time, the greater the difference between the prediction and the actual.

  In the conventional technology, fluctuations in the pump discharge amount are not taken into account. However, in actual water supply pump facilities, the pumping operation raises the water level in the water tank, which increases the actual head required for pump water supply, and the pump discharge amount itself. Also decreases. That is, the pump discharge amount and the outflow amount fluctuate during the pump operation. In order to know the fluctuation of the outflow amount to the outside of the water tank during the pump operation, the fluctuation of the pump discharge amount during the pump operation is known. There is a need.

  Furthermore, in the prior art, the pump rated discharge rate (set value) is used, but when water is supplied with a combination of pumps with different specifications, the sum of the pump rated discharge rate and the actual discharge rate during normal operation of the pump A difference occurs in the sum. This is different from the basic specification because the pump specification based on parallel operation uses the discharge rate during parallel operation as the rated discharge rate, and the pump based on single operation uses the discharge rate during single pump operation as the rated discharge rate. In the operating state, there is a difference between the rated discharge amount and the actual discharge amount, and it is difficult to grasp this difference in advance.

  In the prior art, the upper limit water level arrival time when water supply is completed is predicted, and a decrease in the actual pump discharge amount (air lock or suction blockage) is determined according to the water level state at the predicted time, so it cannot be determined until the expected time is reached There is a drawback that it takes time to determine the decrease in the actual discharge amount of the pump.

Object of the invention

OBJECT OF THE INVENTION
The object of the present invention is to eliminate the drawbacks of the prior art described above, to appropriately cope with fluctuations in the outflow amount during pump operation, to improve the reliability of the integrated outflow volume , and to make an early determination for an abnormal decrease in pump discharge amount. An object of the present invention is to provide a method and an apparatus for predicting the amount of outflow to the outside of a water tank during operation of a feed water pump, which can improve its reliability.

Means to solve the problem

[Means for solving problems]
In order to solve the above-mentioned problem, in the invention described in claim 1, a water tank capable of calculating a volume from a water level change amount, one or more water supply pumps, a water level meter having a signal output function, and the water level meter Using an arithmetic unit that has a data storage function that measures, stores, and stores signals every unit time, the measurement time required for the fluctuation of the water level, the tank volume of the difference in the water level, and the discharge amount calculation formula of the pump In the method for calculating the outflow amount outside the water tank during operation of the feed water pump, the outflow amount outside the water tank during operation of the feed water pump and the outflow amount of the water tank when the feed water pump is stopped are calculated from the obtained pump discharge amount. The calculated discharge amount of the feed water pump with respect to the measured water level of the water level meter by calculating the discharge amount of the feed water pump with respect to the arbitrary water level in the water tank by the formulas 1 to 19 and 21 according to claim 1 calculated from the water level change immediately after. , By calculation of the outflow as shown in Equation 20 according to claim 1, wherein the water level variation in the aquarium (qout), characterized by prediction calculation runoff into the water tank outside in the feedwater pump operation. In the invention according to claim 2, a water tank capable of calculating the volume from the amount of change in the water level, one or more water supply pumps, a water level meter having a signal output function, and measurement for each unit time of the water level meter Computation processing and a data storage function for storing data, equipped with a calculation device, from the measurement time required for the fluctuation of the water level, the water tank volume of the difference in water level, and the pump discharge amount obtained from the discharge amount calculation formula of the pump, In the apparatus for predicting the amount of outflow to the outside of the water tank during operation of the feed water pump for obtaining the amount of outflow during the measurement time zone, it is calculated from the amount of outflow to the outside of the water tank while the water pump is stopped and the change in the water level immediately after the operation of the water feed pump. The discharge amount of the feed water pump with respect to the arbitrary water level in the water tank is obtained by the above-described mathematical expressions 1 to 19, and the mathematical expression 2 is calculated from the calculated discharge amount of the feed water pump with respect to the measured water level of the water level gauge and the water level change amount in the water tank. The computation of runoff (qout) as shown in, outflow of the aquarium outside in the feedwater pump operation, characterized by being configured to allow prediction calculation. Further, in the invention according to claim 3, in the method for calculating the amount of outflow to the outside of the water tank during operation of the water supply pump according to claim 1, when the number of water pumps operating increases, As a result of the change in the water level, the discharge amount after the increase in the number of operating units with respect to the arbitrary water level in the water tank is calculated and added to the outflow volume (ΔVout) at every calculation interval as shown in the mathematical formula 22 of claim 3. By calculating the discharge amount after an increase in the number of pumps operated with respect to the measured water level of the water level gauge. According to a fourth aspect of the present invention, in the method for calculating the amount of outflow to the outside of the water tank during operation of the water supply pump according to claim 1, the calculated discharge amount during normal operation of the water supply pump with respect to the water level measured by the water level meter The equation 11 according to claim 4, wherein learning and storage are performed, and an average discharge amount (Qpm) of the feed water pump at an average water level is obtained from the learned and stored data with respect to a discharge amount calculation result immediately after the operation of the feed water pump. Based on this, it is characterized in that an abnormal drop is determined. Further, in the invention according to claim 5, in the method for predicting the amount of outflow to the outside of the water tank during operation of the feed water pump according to claim 1, the water level meter used has an analog signal output function, and the water level The measurement timing of the analog signal of the meter is changed every unit time, and the water level difference obtained from the difference between the calculated values of each water level for each unit time as shown in the equations 1 and 2 based on the equation 1 Is measured as a unit water level width, and is calculated and stored. The invention according to claim 6 is characterized in that, in the apparatus for predicting the amount of outflow to the outside of the water tank during operation of the water supply pump according to claim 2, the water level meter used has an analog signal output function. To do. Further, in the invention according to claim 7, in runoff prediction calculation unit to the water tank outside in the feedwater pump operation according to claim 2, in water level meter, a function of outputting a digital signal for each unit level width those with is used, or those having a function of outputting a digital signal reaches the unit level width, characterized in that it is used is I union.

Action

  Assuming that the outflow amount while the pump is stopped continues even in the initial stage of pump operation, the pump discharge amount at an arbitrary water level can be obtained from the fluctuation of the water level in the initial stage of pump operation. Further, by calculating the pump discharge amount with respect to the water level fluctuation, it is possible to obtain the fluctuation of the outflow amount during the pump operation. Furthermore, by recording the latest pump discharge amount for each pump combination, the latest pump actual discharge amount can be known.

  According to the present invention, when calculating the pump discharge amount with respect to the fluctuation of the water level, it is assumed that the outflow amount while the pump is stopped continues even in the initial stage of the pump operation. The point that the pump discharge amount is determined by determining the pump discharge amount calculation formula at an arbitrary water level from the fluctuation is the same as in the prior art. However, after the discharge amount calculation formula is determined, the outflow amount in the measurement time zone is obtained from the measurement time required for the water level fluctuation, the tank volume of the difference in water level, and the pump discharge amount obtained from the pump discharge amount calculation formula. .

Assuming that the amount of spillage before the increase in the number of pumps operated continues even immediately after the increase in the number of pumps in operation, such as follow-up operation, By re-determining the pump discharge amount calculation formula at an arbitrary water level from the fluctuation of the water level at the beginning of the increase in the number of pump operations, the discharge amount calculation formula for any combination of pump operation can be obtained by obtaining the discharge amount after the increase in the number of pump operations. It can be confirmed. That is, for example, (1) Measure the water levels y1, y2, y3 in the aquarium at measurement intervals t1, t2, t3 at equal intervals in the initial stage of pump operation. (2) Supply water volume obtained from the water levels y1, y2 and outflow From the amount qout0, the pump discharge amount Qp1 is obtained. (3) The pump discharge amount Qp2 is obtained from the water supply volume obtained from the water levels y2, y3 and the outflow amount qout0. (4) The pump discharge amount is obtained from the pump discharge amounts Qp1, Qp2. The quantity calculation formula Qpm = f (ym) is obtained. (5) After the measurement time t4, the outflow amount is obtained from the water supply volume obtained from the water level and the calculated pump discharge amount. Thus, by calculating the outflow amount at every measurement interval, even if the outflow amount varies after the initial stage of pump operation, the integrated outflow volume corresponding to the variation can be obtained.

  To correct the actual discharge amount (pump performance characteristics) due to the pump operation combination, learning the pump performance characteristics for each pump operation combination when determining the discharge amount calculation formula, the pump actuality due to air lock and suction blockage A decrease in the discharge amount can be determined when the discharge amount calculation formula is determined. Table 1 below shows examples of combination patterns for two pumps.

In the calculation method of the present invention, the following mathematical formula 1 for converting the water level analog value x to the water level industrial unit value y is prepared.

As regards the amount of outflow when the pump is stopped and during the initial operation, it is assumed that the amount of outflow while the pump is stopped is measured and calculated in the same manner as in the past, and the initial operation of the pump continues.

Since the water supply amount is not stable during pump acceleration from the start of the pump, it is assumed that the outflow amount qouto = qouts during the pump start time tp * s (set value). If this relationship is shown by coordinates, it becomes as shown in FIG.

  As the processing at the 0th operation interval, the water level yps: (m) at the pump start time tps: (sec) is calculated by the following formula 2.

  As the first processing of the calculation interval, the calculation of the water level y1: (m) at the pump acceleration completion time t1 = tps + Tp * s: (sec) is performed by the following mathematical formula 3.

Then the calculation interval first process, the pump water supply capacity product .DELTA.Vin: (m3) and the pump discharge amount Qp: computation of (m3 / min) is performed using Equation 5 below.

Then the calculation interval first process, the pump water supply capacity product .DELTA.Vin: (m3) and the pump discharge amount Qp: computation of (m3 / min) is performed using Equation 5 below.

Next, the outflow volume ΔVout (1) is added to the integrated outflow volume (outflow time reference) Vout in the measurement time zone according to the following Equation 6 as the first calculation interval.

  During the pump operation, the pump operation is stabilized and the pump discharge amount decreases as the water level rises. At this time, it is assumed that the pump discharge amount decreases linearly with the rise in water level. Further, it is assumed that the outflow amount qout1 = qout0 also in the initial stage of pump operation. A conversion formula for the pump discharge amount Qpn at an arbitrary water level yn is created from the calculation of t1, t2, and t3 in the initial stage of pump operation, and is used for the subsequent correction of the outflow amount. If this relationship is shown by coordinates, it becomes as shown in FIG.

  As the second processing of the calculation interval, the calculation of the water level [y2: (m)] at the sampling time [t2: (sec)] is performed by the following Equation 7.

Calculation interval as the next second process, performs calculation of the outflow capacity product [ΔVout (m3)] by Equation 8 below.

Calculation interval as the next second process, the pump water supply capacity product [ΔVin: (m3)] and the pump discharge amount: calculation of [Qp (m3 / min)] carried out by Equation 9 below.

Next, the outflow volume [ΔVout] is added to the integrated outflow volume (outflow time reference) [Vout] in the measurement time zone according to the following Equation 10 as the second calculation interval.

  As the second processing of the calculation interval, the average discharge amount [Qpm] at the average water level [y (1-2)] is confirmed from the learning data, and compared with Qp (2) by the following formula 11.

  As the third processing interval, calculation of the water level [y3: (m)] at the sampling time [t3: (sec)] is performed by the following formula 12.

Then the calculation interval third process performs the operation of the outflow capacity product [ΔVout (m3)] using Equation 13 below.

Then as a process of the third computation interval, the operation of the pump water supply capacity product [ΔVin (m3)] and the pump discharge amount [Qp (m3 / min)] performed by equation 14 below.

Next, the outflow volume [ΔVout] is added to the integrated outflow volume (outflow time reference) [Vout] in the measurement time zone according to the following formula 15 as the third processing interval.

  As the third processing interval, the average discharge amount [Qpm] at the average water level [y (2-3)] is confirmed from the learning data, and is compared with Qp (3) by the following equation 16.

  From Equation 17 below, from the change [Qp (2) → Qp (3)] of the pump discharge amount with respect to the change [y (1-2) → y (2-3)], an arbitrary water level [y (m -N)] is calculated for the pump discharge amount [Qpm]. If this relationship is shown by coordinates, it becomes as shown in FIG.

  In Formula 17, the pump discharge amount calculation formula at an arbitrary water level is a change formula in which the pump discharge amount changes linearly with respect to the water level change. That is, for the pump characteristic curve (third-order equation), there are few cases in which the entire characteristic curve is used in the actual operation range. It is judged that there is no problem. Further, the mathematical expression 17 is recorded and learned with respect to the combination pattern of the pump operation. However, the counted up data of each warning is not recorded from the calculation results (Qp1, Qp2).

  As the fourth calculation interval, the water level [y4: (m)] at the sampling time [t4: (sec)] is calculated by the following equation 18.

Then the process of the arithmetic interval fourth, pump discharge amount [Qp: (m3 / min) ] and the water supply capacity product: performed by Equation 19 below the operation of [ΔVin (m3)].

Then the process of the arithmetic interval fourth, outflow volume product [ΔVout: (m3)]及Beauty runoff: carried out by [qout (m3 / min)] Equation 20 below the operation.

Next, the outflow volume [ΔVout] is added to the integrated outflow volume (outflow time reference) [Vout] in the measurement time zone by the following formula 21 as the fourth processing interval.

  The processing after the fifth calculation interval is calculated while correcting the pump discharge amount / outflow amount until the pump is stopped at every calculation interval.

  Regarding the operation of the second and subsequent pumps, since the start time of the second pump cannot be predicted for the calculation processing of the first pump at the start of the second pump, correction of the outflow amount of the first pump is interrupted and immediately before The amount of water supply is calculated using the amount of outflow (correction value). When the calculation of the sampling time [t1n: (sec)] is finalized and the second pump is operated by the sampling time [t1n + 1: (sec)] (sampling time [t2ps: (sec)], .

  As for the calculation processing at the time of starting the second unit, the previous outflow amount [qout1n + 1] is adopted as it is during the pump starting time as in the case of the first unit.

As for the calculation processing during the operation of two units, it is assumed that the pump discharge amount decreases linearly with the rise in the water level as in the first unit, and the outflow amount [qout1n + 1] does not change during acceleration of the pump operation. assuming, seeking pump discharge amount calculation expression of two during operation, it will added to the calculated cumulative outflow volume flowing out volume product of each calculation interval [ΔVout (m3)].

  Next, with respect to the learning function, as the measurement points at the time of pump start, (1) point t1 after the acceleration time has elapsed since the pump start, (2) point t2 after the discharge flow rate calculation interval (time or water level) has elapsed from the above t1, 3 ▼ Learn the characteristic equation for the combination pattern of pump operation from the operation data of three points from the above t2 after the discharge flow rate calculation interval (time or water level) has elapsed, To do. FIG. 4 shows the above relationship in coordinates.

  Based on the operation data at the measurement points t1, t2 and t2, t3, the calculation is performed by the following formulas 23 and 24.

  FIG. 3 shows the pump discharge amount at each average water level calculated by the above formulas 23 and 24 and expressed in coordinates.

  The conversion formula of the pump discharge amount with respect to the arbitrary water level is as the following formula 25.

  The above Qp (max) and Qp (min) are recorded as a pump operation combination pattern. However, the number of records is about 5, and the old data is updated sequentially. As the initial value, an assumed discharge amount Qp (min) at the water level upper limit value of each combination and an assumed discharge amount Qp (max) at the water level lower limit value are registered. Table 2 below shows examples of combination patterns for two pumps.

  When the measured value satisfies the following judgment this time, it is added to the record as the latest value. Judgment 1: There is no contradiction between fluctuations in water level and fluctuations in flow rate. Judgment 2: The water level difference is not too small. Judgment 3: The flow rate is not excessive. Judgment 4: The flow rate is not too low. Determination 5: The flow rate difference is not too small. Examples are shown in Table 3 below.

  In order to average the recording data, for example, the pump discharge amount with respect to an arbitrary water level is calculated by the following formula 26 from five data (upper limit 5 points, lower limit 5 points).

  For carrying out the method of the present invention, for example, an apparatus as schematically shown in FIG. 5 is used.

Effect of the invention

According to the present invention, it is possible to predict and calculate the fluctuation of the spillage amount during the pump operation, and the total spillage volume on the form summary is tallied to a form closer to the actual spillage fluctuation. There is an advantage that you can. In addition, the learning function can be used to know the actual actual discharge amount when the pump is normal, and an abnormal drop in pump discharge amount due to air lock or suction blockage can be determined at the time of discharge amount calculation at the initial stage of pump operation. As a practical effect, it is possible to clearly discriminate between an abnormal decrease in the pump discharge amount due to air lock or suction blockage and a decrease in the discharge amount due to secular change.

  It is a diagram which shows the water level change in the water tank during acceleration from pump starting.   It is a diagram which shows the water level change in the water tank in pump constant speed driving | operation.   It is a diagram which shows the change of the pump discharge amount with respect to the water level change during pump constant speed driving | operation.   It is a diagram which shows the water level change in the water tank in pump operation.   It is a block diagram of one Example of this invention.

Claims (7)

A water tank that can calculate the volume from the amount of change in water level, one or more water pumps, a water level meter with a signal output function, and a data storage function that measures the signal of the water level meter per unit time, and performs arithmetic processing and storage Using the calculation device having, the measurement time required for the fluctuation of the water level, the tank volume of the difference in the water level, and the pump discharge amount obtained from the discharge amount calculation formula of the pump, to determine the outflow amount in the measurement time zone, A method for predicting the amount of outflow to the outside of the water tank during operation of the water supply pump, wherein the equations 1 to 19 and 21 are calculated from the amount of outflow to the outside of the water tank during stoppage of the water supply pump and the change in the water level immediately after operation of the water supply pump. Thus, the discharge amount of the water supply pump with respect to the arbitrary water level in the water tank is obtained, and the outflow amount (qout) as shown in Equation 20 from the calculated discharge amount of the water supply pump with respect to the measured water level of the water level meter and the water level change amount in the water tank Operation, the method characterized by predicting operation the outflow of the water tank outside in the feedwater pump operation.

Formula 1

Formula 2

Formula 3

Formula 4

Formula 5

Formula 6

Formula 7

Formula 8

Formula 9

Formula 10

Formula 11

Formula 12

Formula 13

Formula 14

Formula 15

Formula 16

Formula 17

Formula 18

Formula 19

Formula 20

Formula 21

A water tank that can calculate the volume from the amount of change in water level, one or more water pumps, a water level meter with a signal output function, and a data storage function that measures the signal of the water level meter per unit time, and performs arithmetic processing and storage The amount of outflow in the measurement time zone is obtained from the measurement time required for the fluctuation of the water level, the tank volume of the difference in water level, and the pump discharge amount obtained from the discharge amount calculation formula of the pump . The mathematical expression according to claim 1 , wherein the calculation device calculates the amount of outflow to the outside of the water tank during operation of the water supply pump, and the amount of outflow to the outside of the water tank during stoppage of the water supply pump and the change in water level immediately after operation of the water supply pump. The discharge amount of the feed water pump with respect to an arbitrary water level in the aquarium is obtained from 1 to 19 and 21 , and the calculated discharge amount of the feed water pump with respect to the measured water level of the water level meter and the water level change amount in the aquarium are given by Equation 20. In The computation of runoff in Suyo (qout), device outflow into the aquarium outside in the feedwater pump operation, characterized by being configured to allow prediction calculation.
In operation number increases in the feed water pump, a calculation outflow before the increase, the level changes immediately after the increase, the outflow capacity product of each calculation interval to indicate the discharge amount after the number of operating units increases for any water level in the water tank to the formula 22 2. The feed water pump operation according to claim 1, wherein a discharge amount after an increase in the number of pump operations with respect to a measured water level of a water level meter is calculated by calculating and adding (ΔVout) to calculate an integrated outflow volume (Vout). Calculation method for predicting the outflow amount to the outside of the tank.
Formula 22

The calculation discharge amount at the time of normal operation of the water supply pump with respect to the measured water level of the water tank by the water level meter is learned and stored, and the discharge amount calculation result immediately after the operation of the water supply pump is calculated and stored in the average water level from the learning storage data. The calculation of the amount of outflow to the outside of the water tank during operation of the feed water pump according to claim 1, wherein an abnormal decrease is determined based on Formula 11 according to claim 1 by obtaining an average discharge amount (Qpm). Method.
Water gauge employed be one having an analog signal output function, changing the measurement timing of the analog signals of the water level gauge for each unit time, Equation 1 of claim 1, wherein based on the Equation 1 according to claim 1, The measurement timing is measured and stored as a unit water level width by measuring a difference in water level obtained from the difference between the calculation values of each water level per unit time as shown in claim 2. A method for calculating the amount of outflow to the outside of the water tank while the water supply pump is operating.
The apparatus for predicting the amount of outflow to the outside of the water tank during operation of the feed water pump according to claim 2, wherein the water level gauge used has an analog signal output function.
The water level meter, which has a function of outputting a digital signal for each unit level width is used, or those having a function of outputting a digital signal reaches the unit level width is used is I union The apparatus for predicting the amount of outflow to the outside of the water tank during operation of the water supply pump according to claim 2.

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