JPH0914179A - Method for controlling operation of pump - Google Patents

Abstract

PURPOSE: To eliminate a need to set a plurality of stages of water levels, corresponding to the number of pumps, at a suction water tank and to reduce the depth of the suction water tank by a method wherein from an inflow rate to the suction water tank and an estimated flow rate of drain from the suction water tank, the necessary number of working pumps is decided. CONSTITUTION: The delivery lines 13 of a plurality of drain pumps 11 are connected to a delivery water tank 14 formed in a ground. In control of operation of the drain pump 11, from an inflow rate of a suction water tank 5 and an estimated flow rate of drain from the suction water tank 5, the necessary number N of working pumps is decided. When a water level in the suction water tank 5 attains a starting water level, the number N of the pumps 11 is started and brought into a waiting operation state. When a water level in the suction water tank 5 exceeds a drain starting water level, drainage operation is started to effect control so that a water level in the suction water tank 5 is kept at a constant value. When the number of the working pumps exceeds the necessary number N of the working pumps, the pumps 11 are switched to a waiting operation state. When the waiting operation state is continued for a given time or more, operation of the pumps 11 is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applied to, for example, drainage of a deep underground discharge channel. The number of pumps installed in a drainage pump station is adjusted according to the fluctuation of the water level in the water absorption tank. The present invention relates to an operation control method of a pump to be controlled.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, the water level L of a water absorption tank is generally set in a plurality of stages (L) corresponding to the number N of operating pumps.
1 to Ln), and when the water level L of the water absorption tank reaches each set water level (L1 to Ln) due to the inflow of rainwater etc., the number of pumps (N1 to Nn) corresponding to each set water level is set. The operation control method of starting it was adopted.

[0003]

In the conventional pump operation control method as described above, the number of pumps to be operated is determined by the water levels set in a plurality of stages in the water absorption tank corresponding to the number of pumps. Not only is it necessary to increase the depth of the water absorption tank depending on the number of pumps installed,
Since the pump is started after reaching the predetermined set water level,
When the inflow into the water absorption tank increases rapidly, for example, the water level rises abnormally during the required start-up time of the pump drive such as the gas turbine, and the water level is higher than the set maximum water level corresponding to the number of operating pumps. (Ln in Fig. 5) There is a problem that it may cause serious inconvenience such as inundation of flood pumping station or flood, and in order to avoid such a problem, increase the area of the water absorption tank or increase the depth. It is necessary to increase the size.

The present invention has been made in view of the above-mentioned circumstances, and even if the depth or area of the water absorption tank is not unnecessarily increased, a predetermined drainage is performed regardless of the increase or decrease in the amount of inflow into the water absorption tank. (EN) Provided is a pump operation control method capable of performing a predetermined drainage function without inconvenience such as inability to drain water or an abnormal increase in load by operating a suitable number of pumps when the water level is reached. It is an object.

[0005]

In order to achieve the above object, the pump operation control method according to the present invention needs to measure the inflow amount Qin into the water absorption tank and the expected drainage amount Qout from the water absorption tank, respectively. The pump operating number N is calculated as (Qin <Qou
t × N) is determined to be the minimum that satisfies the relational expression, and when the water level of the water absorption tank reaches the starting water level, the determined number N of pumps are started to enter the standby operation state, and then the water absorption tank When the water level is above the drainage starting water level, the drainage operation is started and the water level in the water absorption tank is controlled to be constant, and the number of pumps operating is greater than the required number of pumps operating due to the change in the drainage operation and inflow Qin. Alternatively, the pump is switched to the standby operation state when the discharge rate of the pump is equal to or less than the operable minimum discharge rate, and the operation of the pump is stopped when the standby operation state continues for a predetermined time or more. It is a thing.

In the pump operation control method, the starting water level is such that the subtraction value of the starting water level from the drainage starting water level is equal to the product of the rising speed of the water level in the water absorption tank and the required starting time of the pump drive device, or It is preferably set to be large.

[0007]

According to the present invention, the required pump operation number N is determined from the inflow amount Qin into the water absorption tank and the expected drainage amount Qout from the water absorption tank to set the water level of a plurality of stages corresponding to the number of pumps in the water absorption tank. There is no need to do so, and the depth of the water absorption tank can be made smaller. Also, when the water level in the water absorption tank reaches the starting water level, the required number N of pumps have been started and are in the standby operation state. Therefore, when the water level exceeds the draining start water level, the draining operation is immediately started and the inflow amount. Regardless of the size, the drainage function will be fulfilled as prescribed, and therefore, there will be no significant inconvenience such as inundation or flooding of the drainage pump station due to an abnormally high water level.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a configuration of an underground drainage drainage system for carrying out a pump operation control method according to the present invention. In FIG. 1, 1-3 are plural (in the drawing, three are shown, but two are shown). Corresponding to the above rivers) are formed in the ground almost vertically in the ground, and their bottoms are inflow shafts connected to the common flow path 4. Weir type flowmeters 1Q to 3Q are installed, and the inflow amount Q1 from each river is set by these flowmeters 1Q to 3Q.
~ Q3 is measured, and the measured inflow amount signals are sent through an optical cable (not shown) to the drainage station 9 described later.
Is transmitted to the pump operation control device 10 composed of a computer installed in the river, and the total inflow Qin (= Q1
+ Q2 + Q3) is calculated.

Reference numeral 5 denotes a water absorption tank, and a drop-type water level gauge 7 is installed in a first vertical shaft 6 which is formed vertically adjacent to the water absorption tank and is measured by the drop-type water level gauge 7. As for the water level, the standby operation (idle operation) start water level when the pipe is not fully filled, that is, the starting water level Hs of the water absorption tank 5 is obtained, and the water level of the first shaft 6 rises as a backup for the weir flowmeters 1Q to 3Q. It is used to calculate the predicted inflow amount Qin from the speed V. This predicted inflow amount Qin is calculated by Qin = V * (A1 + A2 * A3) when the areas of the shafts 1 to 3 are A1, A2, and A3. Further, an ultrasonic water level gauge 8 is installed in the water absorption tank 5, and the water level measured by the ultrasonic water level gauge 8 is used for constant water level control and stop of the water absorption tank 5 by a pump described later.

Reference numeral 11 is a plurality of pumps, 12 is a pump driving device such as a gas turbine, and these are installed in the drainage pump station 9 together with the pump operation control device 10. The discharge pipe line 13 of these pumps 11 is provided. It is connected to a discharge water tank 14 formed in the ground corresponding to a large river R. An ultrasonic water level meter 15 is also installed in this discharge water tank 14, and the outside water level H0 measured by this ultrasonic water level meter 15 is the estimated discharge amount Qout from the actual head performance curve of the pump 11 as shown in FIG. Used to calculate.
In FIG. 4, H1 is a water level corresponding to the bottom plate of the water absorption tank 5, and H4 is a dangerous water level.

Next, an operation control method of a plurality of pumps 11 installed in the drainage station 9 in the underground discharge channel drainage system configured as described above will be described with reference to the flowchart shown in FIG. In this embodiment, it is assumed that the plurality of pumps 11 are all variable speed pumps and are set to be in the low speed standby operation state at the time of startup.

Inflow quantity Q measured by weir flowmeters 1Q to 3Q installed in shafts 1 to 3 corresponding to each river.
The total inflow amount Qin from 1 to Q3 into the water absorption tank 5 is calculated, and the pump discharge amount from the outside water level measured by the ultrasonic water level gauge 15 to the drainage start water level H3 (Fig. 4), that is, the water absorption tank The expected drainage amount Qout from 5 is calculated based on the actual pump head performance curve shown in FIG. The required number N of pumps is calculated from the inflow amount Qin and the expected drainage amount Qout (step S20). The number of required pumps N
Qin + α <Qout × N where α is determined to be the minimum N for which the relational expression of margin is satisfied.

With the flow into the water absorption tank 5, the first
When the water level in the vertical shaft 6 rises and the water level reaches or exceeds the starting water level Hs set as shown in FIG. 4, the required number N of pumps 11 that are determined as described above are activated to perform the low-speed standby operation. The state is set (steps S21 and S22). The starting water level Hs is variably set so as to change according to the inflow amount Qin. That is, H3 -Hs = V * 2 * t, where t is the required start-up time of the pump drive device 12, and is set with a time margin that allows two start-ups in consideration of the start-up failure.

Then, when the water level in the water absorption tank 5 becomes equal to or higher than the drainage start water level H3, the drainage operation is started under the uniform speed water level constant control (steps S23 and S24).
The uniform speed referred to here is to equalize the rotational speeds of all the pumps 11 in operation. There are a case where the inflow amount Qin increases and a case where the inflow amount Qin decreases regardless of the drainage operation of the uniform water level control, and the operation of the pump 11 is as follows according to both cases. Operation is controlled.

Case where the inflow amount Qin increases: In this case, first, the actual number of pumps 11 operating is less than or equal to the required number N of pumps operating, and the number of revolutions of each pump 11 actually operating is When it is determined that the number of pumps has been increased, one additional pump 11 is started (step S25).
On the other hand, if it is determined that the actual number of operating pumps 11 is not equal to or less than the required number N of operating pumps described above,
The pump 11 is accelerated (step S28).

Case in which the inflow amount Qin decreases: In this case, first, the actual number of pumps 11 operating is greater than or equal to the required number N of pumps operating as described above, and the number of revolutions of each pump 11 that is actually operating is When it is determined that the number of pumps is reduced, one pump 11 in operation is switched to the standby operation state, and when the standby operation state is continued for a predetermined time or more preset by the timer, The operation of the pump 11 is stopped (steps S29 to S3).
3) On the other hand, when the actual number of operating pumps 11 is not greater than or equal to the required number N of operating pumps described above, the pumps 11 are decelerated (step S34). Then, when it is determined that the number of pumps 11 being operated is one and the discharge amount is not more than the minimum discharge amount, the pumps 11 are switched to the standby operation state, and the standby operation state is preset by the timer. If you continue for more than a predetermined time
When the pump 11 of the table is returned to the full speed drainage operation state and the water level of the water absorption tank 5 becomes equal to or lower than the stop water level H2 set between the drainage start water level H3 and the starting water level Hs, the last one The operation of the pump 11 is stopped (step S35).
~ S41).

[0017]

As described above, according to the present invention, the required pump operation number N is determined from the inflow amount Qin into the water absorption tank and the expected drainage amount Qout from the water absorption tank. It is not necessary to set the water levels in multiple stages, and the depth of the water absorption tank can be reduced accordingly. Moreover, when the water level in the water absorption tank reaches the starting water level, the necessary number N of pumps are started to enter the standby operation state.
When the water level exceeds the drainage start water level, the drainage operation can be started immediately to suppress an abnormal rise in the water level. Therefore, even if the depth or area of the water absorption tank is not unnecessarily increased, when the specified drainage water level is reached regardless of the increase or decrease in the amount of water flowing into the water absorption tank, the number of pumps adapted to that is operated to drain water. The desired drainage function can be achieved without causing serious inconveniences such as inundation and flooding of the pumping station.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the configuration of an underground discharge channel drainage system that implements a pump operation control method according to the present invention.

FIG. 2 is a characteristic diagram showing an actual head performance curve of a pump used to calculate an expected emission amount.

FIG. 3 is a flowchart illustrating the operation of the pump operation control method according to the present invention.

FIG. 4 is an explanatory diagram of water level conditions.

FIG. 5 is an explanatory diagram of a water level setting situation in a conventional pump operation control method.

[Explanation of symbols]

 5 Water absorption tank 10 Pump operation control device 11 Pump H2 Stop water level H3 Drainage start water level Hs Start water level

Claims (2)

[Claims] 1. The inflow quantity Qin into the water absorption tank and the expected drainage water quantity Qout from the water absorption tank are respectively measured, and the required pump operating number N is determined to be the minimum N for which the relational expression (Qin <Qout × N) holds. Then, when the water level of the water absorption tank reaches the starting water level, the determined number N of pumps are started to put them in a standby operation state, and then when the water level of the water absorption tank becomes equal to or higher than the drainage start water level, the drain operation is performed. Control is performed to keep the water level in the water absorption tank constant after the start, and when the number of pumps operating is greater than the required number of pumps due to changes in the drainage operation and inflow Qin, or the pump discharge is less than the minimum discharge that can be operated. When it is, switch the pump to the standby operation state,
Further, the pump operation control method is characterized in that the operation of the pump is stopped when the standby operation state continues for a predetermined time or longer. 2. The starting water level is set such that the subtraction value of the starting water level from the drainage starting water level is equal to or larger than the product of the rising speed of the water level in the water absorption tank and the required starting time of the pump drive device. The operation control method for the pump according to claim 1.