JPS62282189A - Water supply controller - Google Patents

Abstract

PURPOSE:To eliminate a flow switch by executing the speed control when the quantity of water consumed is high while executing the constant speed control when said quantity is low and stopping a pump through the delivery pressure rise. CONSTITUTION:When the quantity of water consumed is high, a pressure detection signal is compared with a setting pressure by means of a first comparison means 3 which provides a signal to a speed control means 4 so as to execute the speed control. When the quantity of water consumed drops, a timer 6 functions if the output level of the speed control means 4 is lower than a setting level, and a switch 9 is switched upon elapse of predetermined time so as to execute the constant speed operation of pump based upon a constant signal produced from a constant speed generator 8. Consequently, pressure control can be executed without requiring a flow switch.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a water supply control device that detects the discharge pressure of a pump and controls one drive of the pump.

2. Description of the Related Art In a conventional water supply control device, as shown in FIGS. 2 and 3, when the amount of water discharged from the pump 21 is large, the switches 22 and 23 are in the closed state, and the discharge of the pump 21 is stopped. The pressure is detected by the pressure detector 24, and the discharge pressure of the pump 21 detected by the pressure detector 24 is input to the controller 26, and the controller 25 issues a command to the speed control unit 26 to keep the discharge pressure constant. The output speed of the pump 21 is controlled. Assuming that the amount of water used gradually decreases and reaches <Ql as shown in Fig. 3, the Fuco switch 2 detects this, opens the switch 22 to cancel the constant discharge pressure control, and the pump 21 operates according to the pump characteristics. The discharge pressure increases. When the discharge pressure increases and reaches the pressure PH, the comparator 28 operates to open the switch 23 and the operation of the pump 21 is stopped. After that, the water in the pressure tank 28 stored at the pressure PH is used, and the pressure decreases to a preset pressure PL.
When this happens, the switch 23 is closed again and the pump 21 is driven.

Problems to be Solved by the Invention However, in the above configuration, the flow switch 27 has a diameter similar to the diameter of the pipe corresponding to the amount of water normally used, so there is a drawback that it is expensive. Q1
The value of becomes large, and the range in which the discharge pressure is constant becomes narrow. Furthermore, the flow switch 27 cannot detect minute amounts of water due to its mechanism.

Although it is possible to use a highly accurate electromagnetic flowmeter instead of the 70-swiss 270, it has the drawback of being very expensive.

Means for Solving the Problems In order to solve the above problems, the water supply control device of the present invention includes a water supply pump, a pressure detection means for detecting the discharge pressure of the pump, and a pressure detection means for detecting the discharge pressure of the pump. a first comparing means for comparing the discharge pressure of the pump with a preset set pressure; a speed controlling means for controlling the drive of the pump based on the output of the first comparing means; and an output value of the speed controlling means and a preset value. a second comparison means for comparing the output value of the speed control means with the set value; a timer for measuring the time during which the output value of the speed control means is equal to or less than the set value by the second comparison means; a determining means for determining whether the first
a first switch that blocks output from the comparison means to the speed control means and inputs an output from a constant signal generator that outputs a constant signal to the speed control means; A third controller for detecting that the discharge pressure has reached the operation stop command pressure higher than the set pressure.
and a second switch that cuts off the signal path from the speed control means to the pump based on the output of the third comparison means. In the above configuration, when the amount of water used is large, the pressure is reduced. The drive of the pump is controlled by the detection means, the first comparison means, and the speed control means so that the discharge pressure is constant (set pressure). When the amount of water used decreases, the output value of the speed control means decreases, and when the time during which this output value is below the set value reaches a predetermined time,
When the first switch is switched, the output value of the speed control device becomes constant due to the constant signal from the constant signal generator, and the pump is driven at a constant speed. As a result, the discharge pressure of the pump increases, and when it reaches the operation stop command pressure, the second switch is opened and the drive of the pump is stopped.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG.

In FIG. 1, 1 is a pump, 2 is a pressure detection means for detecting the discharge pressure of the pump 1, and 3 is a pressure detection means for comparing the discharge pressure of the pump 1 detected by the pressure detection means 2 with a preset set pressure. 1 is a comparison means, and 4 is a speed control means whose output value changes according to the output of the first comparison means 3. 5 is a second comparison means for comparing the output value of the speed control means 4 and a preset setting value; 6 is a timer for measuring the time period during which the output value of the speed control means 4 falls below the set value by the second comparison means 5; 8 is a constant signal generating device that generates a constant signal; 9 is a constant signal generating device that generates a constant signal; 9 is a speed control means 3 from the first comparing means 3 based on the output of the determining means; This is a first switch that blocks output to the control means 4 and inputs the output from the constant signal generator 8 to the speed control means 4. 1Q is a third comparison means for detecting that the discharge pressure of the pump 1 detected by the pressure detection means 2 has reached the operation stop command pressure higher than the set pressure; 11 is a speed control means 4 based on the output of the third comparison means 10; This is a second switch that cuts off the signal path from the pump 1 to the pump 1. 12 is a pressure tank.

In the above configuration, when the amount of water used is large, the first switch 9 is in the solid line position and the second switch 11 is closed.The discharge pressure of the pump 1 detected by the pressure detection means 2 is the first comparison By means 3, a preset set pressure (
P shown in FIG. ), and the output of the first comparison means 3 is inputted to the speed control means 4 via the first switch 9. The discharge pressure is the set pressure P. When the speed is very low, the output value of the speed control means 4 increases due to the output of the first comparison means 3,
Drive pump 1 at high speed. The discharge pressure is the set pressure P.

If it is higher, the output value of the speed control means 4 becomes smaller due to the output of the first comparison means 3, and the pump 1 is driven at a low speed.

In this way, the discharge pressure of the pump 1 is the set pressure P. becomes constant.

When the amount of water used decreases, the discharge pressure of the pump 1 tends to increase, but at this time, the output value of the speed control means 4 is low due to the output of the first comparison means 3, and the output value of the speed control means 4 is low in the second comparison means 5. The output value of the second comparison means 5 is compared with a preset set value, and when the output value of the speed control means 4 is lower than the set value, the output of the second comparison means 5 is inputted to the timer 6, and the timer 6 measures the time. Ru. When the determining means (a) determines that the time measured by the timer 6 has reached the predetermined time, the output of the determining means 7 causes the first switch to switch from the solid line position to the dotted line position. That is, the output from the first comparison means 3 to the speed control means 4 is prevented and the constant signal outputted from the constant signal generating device 8 is inputted to the speed control device 4. Since the signal is a constant signal, the output value is constant and the pump 1 is rotated at a constant speed. Therefore, the discharge pressure of the pump 1 increases to the set pressure P. When a higher operation stop command pressure PHK is reached,
The third comparison means 10 detects that the discharge pressure of the pump 1 has reached the operation stop command pressure PH, and the second switch 11 is opened by the output of the third comparison means 10 at this time, and the drive of the pump 1 is stopped. will be stopped.

Note that after the drive of the pump 1 is stopped, the water in the pressure tank 12 stored at the pressure PH is used, and when the discharge pressure of the pump 1 decreases and reaches the operation start command pressure PL, it is determined by other comparison means (not shown). The second switch 11 is closed, and the pump 1 is driven at a constant speed by the output of the speed control device 4.

Further, the setting value preset in the second comparing means 5 may be determined by finding the minimum water amount Q1 by pulp operation in operation with the discharge pressure of the pump 1 constant, and using the output value of the speed control device 4 at that time. .

Effects of the Invention As described above, according to the present invention, there is no need to use a mechanical water quantity detector such as a flow switch, reliability is improved, and the range of constant discharge pressure operation is wide, providing stable water supply. Since the range in which the discharge pressure is not constant is narrow,
Its industrial value is great, as a small pressure tank can be used.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a water supply control device showing an embodiment of the present invention, Fig. 2 is a block diagram of a conventional water supply control device, and Fig. 3 is a block diagram of a conventional water supply control device.
The figure is a characteristic diagram showing the relationship between the discharge amount and the head (discharge pressure) of a general pump. 1...Pump, 2...Pressure detection means,
3...First comparison means, 4...Speed control means, 5...Second comparison means, 6...Timer, End... Judgment means, 8... constant signal generator, 9... first switch, 10...
...Third comparison means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] A water supply pump, a pressure detection means for detecting the discharge pressure of the pump, a first comparison means for comparing the discharge pressure of the pump detected by the pressure detection means with a preset set pressure, and the first a speed control means for controlling the drive of the pump by the output of the comparison means; a second comparison means for comparing the output value of the speed control means with a preset setting value; and a speed control means for controlling the speed by the second comparison means. a timer for measuring the time during which the output value of the means is equal to or less than the set value; a determining means for determining that the time measured by the timer has reached a predetermined time; and an output from the determining means to determine the speed from the first comparing means. A first switch that blocks output to the control means and inputs an output from a constant signal generator that outputs a constant signal to the speed control means, and a discharge pressure of the pump detected by the pressure detection means is set to the setting. a third comparison means for detecting that an operation stop command pressure higher than the pressure has been reached; and a second switch for cutting off a signal path from the speed control means to the pump based on the output of the third comparison means. Control device.