JPS63162999A - Control method for pressurized water feeding device - Google Patents

Abstract

PURPOSE:To suppress the excessive pressure by operating a pump at the preset rotating speed when the detection signal of a pressure sensor at the discharge side drops or rises abnormally. CONSTITUTION:A confirming circuit 12 judges that the output signal of a pressure sensor 4 is outside the normal preset range, the control pressure of a pressure regulator 7 is switched, and the control output of a stand-by operating circuit 10 is inputted as the speed command signal of a variable-speed device 6. A pump 2 is operated at the running speed set lower than the running speed by a commercial power supply 1. Accordingly, the excessive pressure when an abnormality occurs can be suppressed, and the operating power can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a pressure-feeding water supply device that operates a pump at variable speeds to forcefully feed water.

[Conventional technology]

For example, FIG. 3 is a flow sheet showing a control method for a conventional pressure-feeding water supply device, and FIG. 4 is a flow chart explaining the above-mentioned control method.
) is a commercial Wl source that supplies power to the device, (2) is a pump that pumps water, (3) is an electric motor that operates pump (2), and (4) is pressurized by the operation of pump (2). A pressure sensor that detects water pressure and converts it into an electrical signal, (5) a comparator consisting of an electric circuit that determines the magnitude of the detection signal from the pressure sensor (4), and (6) an electric motor (3) A variable speed device (7) controls the rotation speed of the variable speed device (7) so that the water pressure detected by the pressure sensor (4) becomes the set water pressure.
The pressure regulator that controls ll (6), (8) is the commercial electric power 1!
i (1) is a constant speed switch that is operated when the electric motor (5) is operated at a constant rotation speed directly with the voltage, (9) is a constant speed switch that is operated when the electric motor (3) is operated by the variable speed device (6). The variable speed switch to be operated, ■ is the constant speed switch when the water pressure detected by the pressure sensor (4) is abnormally high or low compared to the water pressure set by the comparator (5). (8) is a constant speed switching circuit that opens the speed change switch (9) and closes the speed change switch (9). In addition, in Fig. 4, (2) is detected by the pressure sensor (7), and when the detected pressure (represented by Pp after pressure) becomes abnormally high or low, the foreshadowing occurs. This confirmation circuit mainly consists of a timer circuit that determines whether the situation is instantaneous or persistent.

Next, the operation will be explained. First, the operation during normal operation will be explained. This pressure water supply system operates the pump (2) at variable speed and controls the feed bar so that the pressure detected by the pressure sensor (4) remains at a set constant pressure even if the amount of water used changes. . The output change of the pressure regulator (7), which is the main equipment that performs this feed bar control, increases when the detected pressure is lower than the set pressure.
Also, when the detected pressure becomes higher than the set pressure, it operates in a decreasing direction. - For example, if the amount of water used increases and the water pressure at the pressure sensor (4) also decreases, the output of the pressure regulator (7) will increase from the current value. Proportional to this output signal
The output of the τ variable speed device (6) is proportional and increases with .
The speed of the electric motor (3) and the pump (2) increases, and the pressure increases by a factor T commensurate with the increase in speed, approaching the set pressure. In this way, during normal times, ' (4
)-p(5)→(7)→(6)-(91-(3)-
(2) - (4) Pressure control is performed by feed bar I control in the closed loop. Next, the operation during abnormal operation will be explained. The mainstream pressure sensor (4) has a one-piece structure in which a pressure detection part and an electric circuit part that converts the detected pressure into an electric signal are integrated into one, and is installed directly connected to a water pipe.

By the way, the pressure sensor (4) is a device that is likely to malfunction among the devices of the feedbark control system as described below.

(1) Water pipes are constantly exposed to vibrations.

(2) When water hammer occurs in water piping, the excessive pressure generated at that time may exceed the rated pressure of the pressure sensor (4), and repeating excessive pressure will shorten the service life. .

(3) Pressure sensor (
4) Condensation is likely to occur in the internal electrical circuit.

For example, if a wire breakage occurs inside the pressure sensor (4) due to the above reasons and the output becomes zero, the comparator (5) detects the abnormality in the signal and the confirmation circuit @ opens and closes the gear shift switch after a predetermined period of time. Open the switch to interrupt variable speed operation, and close the constant speed switch instead! The motive (3) and pump (2) are commercial type @
Operate at maximum speed at voltage (1).

Also, in this case, when the output signal of the pressure sensor (4) becomes an abnormally large output, the comparator (5) detects the signal abnormality and performs the same operation as when the output of the pressure sensor (4) is zero. The control has switched to constant speed operation. The pressure change at this time is the fifth
This will be explained with a diagram. Note that FIG. 5 shows the general pressure-flow rate characteristics of a pump (2) that rotates an impeller and applies pressure energy to water by its centrifugal force. In the figure,
P^ is the power line (1), t-movement 1 (3) and pump (2)
This shows the pump characteristics when driven. Pa indicates the pump characteristic that passes through the set pressure Pc when the flow rate used is Qm when pressure is controlled by feed bar control, and this pump characteristic Pc changes as the flow rate Q^ changes. , changes in order to maintain the set pressure Pc.

In Fig. 5, when an abnormality occurs in the water used fiiQ^ and the operation is switched to commercial 11'5 (1), the set pressure Pa increases to Pmu after switching, so P^-
The difference in Pc is the excessive pressure generated by switching, which causes harmful effects.

[Problems that the invention attempts to solve]

Conventional pressure water supply systems are controlled in the manner described above, so in the event of an abnormality, the pressure will increase unnecessarily.
In particular, as the amount of water used approaches zero, the pressure rise becomes excessive, and the power consumption of the electric motor increases by the amount of excess pressure. In addition, if the piping is old, there is a risk of the piping bursting due to excessive pressure.This invention was made to solve the above-mentioned problems. It is an object of the present invention to provide a device that can reduce excessive pressure rise and also suppress power consumption in abnormal situations.

[Means for solving problems]

In the control method of the pressure water supply system according to the present invention, the pump speed in the event of an abnormality is set in advance to a speed lower than the operating speed by commercial tS, and the pump speed is set in advance to operate at the preset speed in the event of an abnormality. .

[Effect]

A method of controlling a pressure water supply system according to the present invention is to switch to a previously set gamma pump speed when a detected value of a pressure sensor is abnormal. [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is, for example, a flow sheet showing a control method for the pressure-feeding water supply device of the present invention, and the second factor is a flow chart explaining the above-mentioned control method. In FIG. 1 and FIG. 2, the same reference numerals as in FIG. 8 and FIG. 4, which show the conventional example, indicate the same parts, and the explanation will be omitted. In Figures 1 and 2, QLI
is a standby operation circuit that presets the operating speed in the event of an abnormality,
αD is a selection circuit that selects the output of the reaction force regulator (7) which performs normal control and the output of the standby operation circuit αG which performs abnormality control.

Next, the operation will be explained. Since the operation and control method during normal times are the same as those in the prior art, the explanation will be omitted, and the operation during abnormal times will be explained. The comparator (5) constantly determines whether the output signal of the pressure sensor (4) is a normal value and within a predetermined range, or is zero, abnormally high, or abnormally low. if.

If it is an abnormal value, the confirmation circuit @ confirms whether this value is a transient value or a continuous abnormality caused by pressure generation in the pressure sensor (4). Confirmation circuit @ in case of continuous one
When the time is up, the control output of the pressure regulator (7) is stopped or switched, and the control output of the standby operation circuit αa is inputted as the speed command signal of the variable speed device (6). Since the operating speed in case of abnormality is preset in the standby operation circuit αG,
The pump (2) will be operated at the set speed. This set speed is set lower than the operating speed by the commercial power source (1) to alleviate abnormal pressure rise.

To explain these with reference to Fig. 5, when the volume of water used is 9 people, the pressure sensor (4) becomes abnormal and the pump characteristics at this time become the standby operation characteristics shown by Ps, and the pressure at this time is PB. The value is shown in .

Here, the overpressure suppression effect compared to the conventional technology is PA-PB
The difference is

In addition, in the above embodiment, a case was explained in which a faulty pressure sensor (4) occurred, but the same phenomenon as when pressure is generated due to a faulty pressure sensor (4) occurs in the following case as well. Therefore, the same effect as above is achieved.

(1) If the electrical wiring from the pressure sensor (4) to the comparator (5) is disconnected (2) If the water in the pipe to which the pressure sensor (4) is attached falls. In this case, can you run pump (2) without water? ! The effect of improving the burnout protection effect of the pump (2) during operation is further added.

〔Effect of the invention〕

As described above, according to the present invention, when an abnormality occurs,
Since the pump is operated at a preset speed, it is possible to suppress excessive pressure and reduce operating power when an abnormality occurs, and also to prevent burnout of the pump.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a method of controlling a pressure water supply system according to an embodiment of the present invention, FIG. 2 is a flowchart showing a method of controlling a filtration water supply system according to an embodiment of the invention, and FIG. FIG. 4 is a flowchart showing a method of controlling a water supply device. FIG. 4 is a flowchart showing a method of controlling a conventional pressure-feeding water supply device, and FIG. 5 is a diagram showing general pressure-flow characteristics of a pump. In the figure, (2) is a pump, and (4) is a pressure sensor.

Claims (1)

[Claims] In a pressure water supply system that supplies water under pressure by operating a pump at variable speeds, if the detection signal of a pressure sensor that detects the pressure of water being supplied under pressure abnormally decreases or increases, the pump operates at a preset rotational speed. 1. A method of controlling a pressure-feeding water supply device, characterized by operating a pressure-feeding water supply device.