JPH0374584A - Alternate driving method for pump - Google Patents

Abstract

PURPOSE:To uniform the operating time of each pump by providing a controller for controlling in such a way that a mode is switched each time the water level falls and a pump positioned as a first pump in operational sequence as well as automatically operated longest among the pumps is stopped being positioned as the last pump in a new mode. CONSTITUTION:A device for discharging water reserved in a feed water drum through a collecting pipe 3 by the parallel operation of No.1-5 pumps 2a-2e is provided with a programmable controller 7 actuated when the driving of the pumps is selected to the automatic operation side by a manual/automatic switching selector switch 5. This controller 7 is formed of a water level converting circuit 10, a mode switching circuit 11 and a pump operation automatic control circuit 12. On the basis of the output of a level gage 4 for detecting the water level for operating adding/decreasing the number of the pumps, a pump is started according to a certain mode at the rising time of the water level so as to perform add operation and switching to the following mode is automatically performed at the falling time of the water level, and the pump is stopped according to this new mode so as to perform decrease operation.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for alternately operating a pump.

(Conventional technology) In order to operate drainage pumps economically in drainage facilities, etc., multiple pumps are installed separately so that the required number of pumps to be operated can be selected according to fluctuations in the water level of the water suction tank. . In such a pumping station, for example, when three pumps are in operation and the water level rises to the level required for the fourth operation, the fourth pump is automatically started and the number of pumps in operation is added, and the water level rises to four.
When the water level drops to a level that does not require operation of the fourth pump, the fourth pump is automatically stopped and the number of pumps is reduced.

In this case, the first three pumps continue to operate, and the fourth pump repeatedly starts and stops as the water level rises and falls, and its operation duration is longer than that of the first three pumps. It's significantly shorter than that. In this way, uneven operation times can cause some pumps to break down or parts to wear out, so it is necessary to operate the pumps alternately so that the operation time of each pump is equalized. .

For this reason, conventionally, a selector switch is provided that allows manual selection of a plurality of modes in which the pump operation order differs at any time. While a certain mode is selected by this selector switch, the pumps are automatically started and stopped as described above according to the operating order of the mode.

That is, for example, the pump is No. 1 to No. 5.
When the stand is installed and mode l is selected, as the water level rises, No, 1 → No, 2-
They are activated in the order of +Na, 3-+Na, 4-+Na, and 5, and as the water level falls, contrary to the above, No., 5.
→No, 4-4N0.3-+Na, 24N0.1 are stopped in this order. Therefore, in mode 1, the last pump to start is the first to stop as the water level drops, so the total operating time is significantly shorter than other pumps.
In addition, there is a biased tendency that the pump started first in mode 1 has the longest total operating time.

Therefore, in order to equalize the operating time of each pump, the operator has to do it every week! The selector switch was operated every few times to switch to a different mode. For example, from the mode l, the startup order is No, 24
No.3-+Na, 4-+Na, 54No.1,
Stop order is No, 1->No, 5-+Na, 4-
By switching to mode 2, which is +Na, 3-+Na, 2, No. 2, which had the longest operating time in mode 1,
, One pump was set to the last position in mode 2 to shorten the operating time and make the operating time uniform overall.

(Problem to be Solved by the Invention) However, in an operating method that requires periodic mode switching artificially using a selector switch, the operation is extremely complicated, and when the water level fluctuates rapidly, it is not always possible to There was a problem that the operating time of each pump was not equalized.

The present invention has been made in view of such problems, and an object of the present invention is to provide a method for alternately operating pumps that can automatically equalize the operating time of each pump.

(Means for Solving the Problem) In order to achieve the above object, the present invention alternately controls a plurality of pumps arranged in a water suction tank while automatically controlling the number of pumps according to the water level of the water suction tank. In the method of alternately operating pumps, water level detection means is provided to detect the water level at which an additional number of pumps should be operated and the water level at which a reduced number of pumps should be operated. A plurality of modes are provided in which the operating order of the pumps is sequentially shifted so that the first pump becomes the last pump in the next mode, and when the water level rises, the pumps are started according to a certain mode based on the signal from the water level detection means. When the water level drops, the pump automatically switches to the next mode based on the signal from the water level detection means, and according to this new mode, the pump is stopped and reduced operation is performed.

(Function) When the water level in the water absorption tank rises, the number of units is added according to the operating order of a certain mode. Therefore, the pump that is ranked earlier in the mode has a longer operating time.

Furthermore, when the water level in the water suction tank falls, the pumps are automatically switched to the next mode, so the pumps are stopped and the number of pumps is reduced according to this new mode. That is, in the new mode, the pump that ranked first and had the longest operating time in the previous mode is placed last and is stopped.

(Example) Next, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a pump device to which the present invention is applied, l is a water absorption tank communicating with a reservoir etc. (not shown), 2a2b, 2
c, 2d, 2e are No, 1. No,
2. No, 3 No, 4, No, 5 pumps,
The water stored in the water absorption system 1 is discharged through the collecting pipe 3 in parallel operation. Also, 4 is a water level gauge, water absorption $
It is designed to emit a signal whose current value changes according to the water level in 11, and the water level at which additional pumps should be operated is from the 1st gold starting water level to the 5th gold starting water level.
The water levels to be operated by reducing the number of pumps, that is, the total 10 water levels from the stop water level of the fifth pump to the stop water level of the first pump, are adjusted so that they fall within the range of, for example, 4+aA to 20+lA.

As shown in FIG. 2, this pump device includes a control circuit consisting of a selector switch 5, a pushbutton switch 6, a programmable controller 7, an indicator light 8, and a main contactor/off operation circuit 9. equipment is provided.

The selector switch 5 is for selecting whether to drive each pump manually or automatically. When automatic is selected, the selection signal is input to the programmable controller 7, and manual is selected. If the selection signal is selected, the selection signal is input to the push button switch 6.

The pushbutton switch 6 is manually operated to switch each pump 2a to
A separate activation signal for 2e is output.

The programmable controller 7 includes a water level conversion circuit IO, a mode switching circuit ll, and a pump operation automatic control circuit 12.
It is composed of.

The water level conversion circuit 10 receives the water level detection signal input from the water level meter 4, and first determines which unit it is a start water level signal or a stop water level signal based on the current value. If the input signal is, for example, a third unit starting water level signal, the third unit starting water level signal is output to the pump operation automatic control circuit 12, and this output state is maintained.

Also, if the input signal is, for example, the third unit stop water level signal, on the condition that the output state of the third unit start water level signal is maintained! At the same time as the shot pulse signal is output to the mode switching circuit 11, the output of the third unit starting water level signal is canceled. Therefore, even if the water level meter 4 outputs a stop water level signal by passing the stop water level while the water level is rising, the water level conversion circuit 10
The current mode is maintained without outputting a pulse signal.

The mode switching circuit 11 receives the nopulse signal input from the water level conversion circuit 10, switches from the current mode to the next mode among the five modes, and uses this switched new mode signal to control the indicator light 8 and automatic pump operation control. The signal is output to the circuit 12.

The pump operation automatic control circuit 12 includes the mode switching circuit 1
In response to the mode signal from 1 and the starting water level signal from the water level conversion circuit 10, starting signals for each pump 28 to 2e are generated by an AND circuit and an OR circuit as shown in FIG. .

That is, for No. 1 pump, an AND circuit Al whose input signals are the mode I signal and the I gold starting water level signal is used.
a, an AND circuit Alb whose input signals are the mode 2 signal and the 5th unit starting water level signal, an AND circuit Ale whose input signals are the mode 3 signal and the 4th unit starting water level signal, the mode 4 signal and the 3rd unit starting water level signal. AN that uses the starting water level signal as an input signal
D circuit Ald, AND circuit Ale whose input signals are the mode 5 signal and the second unit startup water level signal, and each AND circuit A
1a=The output signal of A1e is used as the input signal, and No.

1 and an OR circuit 01 that outputs a pump activation signal.

Pumps No. 2 to No. 5 have similar circuit configurations, and are configured such that the operating order in each mode is as shown in Table 1.

Table 1 The starting signal for each pump output from this pump operation automatic control circuit 12 is input to the AND circuit A together with the automatic operation signal from the selector switch 5, as shown in FIG. The output signal to the AND circuit is input to the OR circuit O together with the activation signal from the pushbutton switch 6, and the output signal of this OR circuit 0 is input to the main contactor/off operation circuit 9. There is.

The indicator lamp 8 receives a mode signal from the mode switching circuit 11 and lights up a mode indicator lamp corresponding to the mode signal. This allows you to check the current driving mode.

The main contactor/off operation circuit 9 receives the start signal for each of the pumps 2a to 2e from the programmable controller 7, turns on the power supply circuit to the drive motor of each pump 2a to 2e, and outputs the start signal. It is designed to turn off on loss of input.

In the control device for the pump device having the above configuration, it is assumed that the selector switch 5 is currently in the automatic position, the operation mode is mode 1, and the water suction tank weight is at the second unit startup water level.

In this case, the mode switching circuit 11 outputs the mode l signal to the indicator light 8 and the pump operation automatic control circuit 12, and the water level conversion circuit 10 outputs the mode l signal to the pump operation automatic control circuit [2] based on the water level detection signal from the water level gauge 4. The pump operation automatic control circuit 12 outputs a No. 1 pump activation signal and a No. 1 pump activation signal through an AND circuit A1a and an OR circuit O1 shown in FIG. No via AND circuit A2a and OR circuit 02.

2 pump start signal is output. As a result, No.

The No. 1 pump 2a and the No. 2 pump 2b are in operation, and the indicator light 8 indicates mode 1.

Assuming that the water level in the water absorption tank l rises from this state and reaches the third unit startup water level, the water level meter 4 outputs a detection signal with a current value corresponding to the water level, and the water level conversion circuit lO of the programmable controller 7 In response to this detection signal, a third unit starting water level signal is output to the pump operation automatic control circuit 12. As a result, the pump operation automatic control circuit 12 receives the third unit starting water level signal and the mode I signal, and outputs the AND circuit A3a.

A No. 3 pump activation signal is output via the OR circuit 04. Therefore, in addition to the No. 1 pump 2a and the No. 2 pump 2b that are already in operation, the No. 3 pump 2c is additionally operated. As a result, the operation time of No. 1 pump is the longest.

In addition, while the water level rises from the second unit starting water level to the third unit starting water level, the water level meter 4 detects the third unit stopping water level, but at this time, the output state of the third unit starting water level signal is not maintained. , the water level conversion circuit 1O does not output a pulse signal to the %-mode conversion circuit 11, and mode 1 is maintained.

Next, when the water level in the water absorption tank l drops to the third stop water level, the water level meter 4 outputs a detection signal with a current value corresponding to the water level, and the water level conversion circuit 10 receives this detection signal. At the same time, a pulse signal is output to the mode switching circuit 11, and at the same time, the output state of the third unit starting water level signal is canceled. As a result, the mode switching circuit 11 switches the operation mode to mode 2, causes the indicator light 8 to light up mode 2, and outputs a mode 2 signal to the pump operation automatic control circuit 12. Note that the water level conversion circuit 10 holds the output states of the first-unit start-up water level signal and the second-unit start-up water level signal.

Therefore, the pump operation automatic control circuit 12 outputs the No. 2 pump activation signal through the AND circuit A2b and the OR circuit 02, and outputs the No. 3 pump activation signal through the AND circuit A3b and the OR circuit 03. , the AND circuit Atb to which the mode 2 signal is input does not output the No. 1 pump activation signal unless the 5th unit activation water level signal is simultaneously input. As a result, No. 2 pump 2b and No. 3
Pump 2c continues to operate and has the longest operating time N
o, l Pump 2a stops operating.

In this way, the No. 1 pump 2a that has the longest operating time during the additional operation in mode 1 will stop first and enter reduced operation when mode 2 is entered, so each pump 2a to 2e
The operating time of the system is automatically equalized.

By the way, when the selector switch 5 is switched to the manual position, by appropriately selecting and operating the individual pushbutton switches 6 corresponding to each pump 23 to 2e, an arbitrary mode different from the automatic mode can be selected. Pumps can be operated in combination.

In the above example, a water level meter that outputs a continuous signal with a current value of, for example, 4 to 20 IIIA was used as the water level detection means, but each starting water level to be detected.

A float switch or the like may be provided that outputs an on/off signal for each stop water level.

(Effects of the Invention) As is clear from the above description, according to the present invention, the mode switches each time the water level drops, and the pump that was first in the operating order and had the longest automatic operation in the previous mode is
When the new mode is activated, the pumps will stop at the final position, so even if the water level fluctuates drastically, the operating time of each pump will be equalized. In addition, mode switching is done automatically, so
This has the effect of improving operability.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a pump device to which the present invention is applied, FIG. 2 is a block diagram of a pump control device, and FIG. 3 is a logic circuit diagram of an automatic pump operation control circuit. 1... Water absorption tank, 2a, 2b, 2c, 2d, 2e-pump, 4... Water level gauge (water level detection means).

Claims (1)

[Claims] (1) In the alternate operation method of pumps, in which multiple pumps installed in a water suction tank are operated alternately while automatically controlling the number of pumps according to the water level of the water suction tank, additional pumps are operated. A water level detection means is provided to detect the water level at which the pump should be operated and the water level at which the number of pumps should be operated by reducing the number of pumps. A plurality of modes are set in a sequentially shifted order, and when the water level rises, the pump is started and additionally operated according to a certain mode based on the signal from the water level detection means, and when the water level falls, the pump is operated additionally according to the signal from the water level detection means. A pump alternate operation method characterized in that the pump is automatically switched to the next mode based on the new mode, and the pump is stopped and operated at a reduced rate according to this new mode.