JP2023072979A - Water supply system - Google Patents

Abstract

To disclose one embodiment of a water supply system that can determine a target pressure to a proper value.SOLUTION: A water supply system 1 includes: a flow-rate sensor Fs capable of continuously detecting a water supply amount; and a control device 4 for executing target pressure control using a value which is determined as a function value which uses a detection value of the flow-rate sensor Fs as a variable number, as a target pressure; hence the water supply system is free from any influence from push-in pressure when determining a target pressure and can determine the target pressure to a proper value.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to a water supply device including an electric pump for water supply.

The electric pump of the water supply device is controlled so that the discharge pressure of the electric pump becomes the target pressure, as described in Japanese Unexamined Patent Application Publication No. 2002-200013. A predetermined value or a value automatically determined based on the driving frequency of the electric pump is normally used as the target pressure. The drive frequency is the frequency of the drive current when driving the electric motor of the electric pump.

Japanese Patent No. 4263812

By the way, even if the driving frequency is the same, if the pushing pressure acting on the suction side of the electric pump changes greatly, the discharge flow rate of the electric pump changes accordingly. If the change width of the pressing pressure is large, the actual discharge flow rate will change greatly even if the drive frequency is the same.

Therefore, if the target pressure amount is determined based on the drive frequency, the target pressure may not be an appropriate value. In view of this point, the present disclosure discloses an example of a water supply device in which the target pressure can be determined to be an appropriate value.

A water supply device including an electric pump (2) desirably includes at least one of the following components, for example. That is, the constituent elements are a flow sensor (Fs) capable of continuously detecting the amount of water supply, a pressure sensor (Ps1) for detecting the discharge side pressure of the electric pump (2), and a detection of the flow sensor (Fs) A control unit (4) capable of executing target pressure control using the value (Q) and the detected value (P1) of the pressure sensor (Ps1), and as a function value with the detected value of the flow sensor (Fs) as a variable When the determined value is the target pressure (Pt), in the target pressure control, the electric pump (2) is controlled so that the detected value (P1) of the pressure sensor (Ps1) becomes the target pressure (Pt). is.

Thus, in the water supply device, the target pressure (Pt) is determined as a function value with the detected value of the flow rate sensor (Fs) as a variable. Therefore, the target pressure (Pt) of the water supply device is not affected by the pressing pressure.

That is, the target pressure is generally set to a value such that the water supply pressure (hereinafter referred to as the terminal pressure) at the point farthest from the water supply system can be maintained at a predetermined pressure (hereinafter referred to as the target terminal pressure). set.

The pressure of water discharged from the electric pump (2) decreases toward the end, that is, the farther away from the electric pump. Therefore, in order to maintain the terminal pressure at the target terminal pressure, it is necessary to set the discharge pressure of the electric pump to a value equal to or higher than the sum of the pressure loss generated until the flowing water reaches the terminal.

The pressure loss changes according to the flow velocity of the running water. On the other hand, in the water supply device, the target pressure (Pt) is determined as a function value with the detected value of the flow rate sensor (Fs) as a variable. determined as a value. Therefore, in the water supply device concerned, target pressure (Pt) can be determined as an appropriate value.

In addition, in a water supply device that includes an electric pump (2) having a rotating impeller and the suction side of the electric pump (2) is connected to a water pipe, for example, at least one of the following components may be provided. desirable.

That is, the constituent elements include a backflow prevention device (3) provided on the suction side of the electric pump (2), pressure sensors (Ps1, Ps2) for detecting water pressure, and stop and operation of the electric pump (2). A pressure (P1) detected by a pressure sensor (Ps1) in a pump control unit (4) to control when the electric pump (2) is stopped has become equal to or less than a predetermined pressure (hereinafter referred to as starting pressure). a pump control unit (4) capable of executing start-up control to start the electric pump (2) when the electric pump (2) is stopped; An anti-freezing control unit (4) that controls the stop and operation of anti-freezing control, and the anti-freezing control unit (4) performs anti-freezing control when the pressing pressure (Pp) is equal to or higher than the pressing rotation pressure (Pr) is to be stopped.

The pushing pressure (Pp) is the pressure detected by the pressure sensor (Ps2) when the electric pump (2) is stopped. Indentation rotational pressure (Pr) refers to a predetermined pressure greater than the starting pressure.

In the water supply device, when the pressing pressure (Pp) is equal to or higher than the pressing rotation pressure (Pr), the pressing pressure (Pp) can rotate the impeller of the electric pump (2). Since the rotation of the impeller prevents the inside of the electric pump (2) from freezing, the anti-freezing control section (4) stops the anti-freezing control.

Incidentally, the symbols in each parenthesis above are examples showing the correspondence with the specific configurations and the like described in the embodiments described later, and the present disclosure is not limited to the specific configurations and the like indicated by the symbols in the parentheses. .

It is a figure which shows the water supply apparatus which concerns on 1st Embodiment. It is a figure which shows the structure of a flow sensor. 4 is a flowchart showing an example of pump control; 4 is a flowchart showing an example of anti-freezing control; 4 is a flow chart showing an example of warning operation;

The following "embodiment of the invention" shows an example of an embodiment belonging to the technical scope of the present disclosure. In other words, the matters specifying the invention described in the claims are not limited to the specific configurations, structures, etc. shown in the following embodiments.

It should be noted that arrows and oblique lines indicating directions in each drawing are provided to facilitate understanding of the relationship between the drawings and the shape of each member or portion. Accordingly, the inventions shown in this disclosure are not limited to the orientations attached to each figure. Figures with hatching are not necessarily cross-sectional views.

At least one member or portion described with at least a reference numeral is provided unless otherwise specified as "one" or the like. In other words, two or more members may be provided unless there is a notice such as "one". The water supply apparatus shown in the present disclosure includes at least components such as the members or parts described with reference numerals, as well as the structural parts shown.

(First embodiment)
<1. Outline of water supply equipment>
In this embodiment, an example of the water supply apparatus according to the present disclosure is applied to a direct water supply apparatus. A direct connection type water supply device is a water supply device that can supply water using water pressure. For this reason, the water supply device 1 does not include a water storage device such as a water receiving tank.

As shown in FIG. 1, the water supply device 1 according to this embodiment includes at least one (in this embodiment, a plurality) electric pump 2, a backflow prevention device 3, a control device 4, and the same number of flow rates as the electric pump 2. It includes at least a sensor Fs, a first pressure sensor Ps1, a second pressure sensor Ps2, the same number of temperature sensors Ts as the electric pump 2, pressure accumulators 5, and the like.

Each electric pump 2 includes one or more impellers (not shown), an electric motor (not shown) for rotating the impeller, and the like. Hereinafter, when the plurality of electric pumps 2 are collectively referred to, they are simply referred to as the electric pumps 2 .

The suction side of the electric pump 2 is connected to water pipes. The discharge side of the electric pump 2 is connected to a building water supply pipe (not shown). The pressure accumulator 5 is connected to the discharge side of the electric pump 2 and holds the water supply pressure when the electric pump 2 is stopped.

A suction side and a discharge side of the electric pump 2 are connected via a bypass pipe 6 . The bypass pipe 6 is provided with a check valve 6A. The check valve 6A prohibits water from flowing from the discharge side to the suction side.

The backflow prevention device 3 is provided on the suction side of the electric pump 2 . In other words, the backflow prevention device 3 has an inflow side connected to the water pipe and an outflow side connected to the suction side of the electric pump 2 . The backflow prevention device 3 prohibits water from flowing into the water pipe from the water supply device 1, that is, backflow.

A first pressure sensor Ps1 detects the water pressure on the discharge side of the electric pump 2 . The second pressure sensor Ps2 detects the water pressure on the suction side of the electric pump 2 (the inflow side of the backflow prevention device 3 in this embodiment), that is, the water pressure. The pressure detected by the first pressure sensor Ps1 is hereinafter referred to as the discharge pressure P. The second pressure sensor Ps2 is called a pressing pressure Pp.

Each temperature sensor Ts detects water temperature. Each temperature sensor Ts according to this embodiment is arranged on the suction side of each electric pump 2 . Each flow sensor Fs detects the amount of water supply in the water flowing passage between the backflow prevention device 3 and the electric pump 2 , that is, on the suction side of the electric pump 2 .

The flow rate sensor Fs according to this embodiment is a flow rate sensor capable of continuously detecting the amount of water supply. Specifically, each flow sensor Fs is configured with an impeller Fi as shown in FIG. The impeller Fi is rotatable around the virtual line O2. The virtual line O2 is an axis line parallel to the direction orthogonal to the central axis line O1 of the water passage Fl.

Each impeller Fi is arranged in the flowing water passage Fl between the backflow prevention device 3 and each electric pump 2, and rotates under the dynamic pressure of the flowing water on the central axis O1 side of the virtual line O2. . Note that the central axis O1 is a virtual normal line passing through the center of the cross section of the flowing water passage Fl.

Incidentally, a temperature sensing part (not shown) of each temperature sensor Ts according to the present embodiment is arranged near each impeller Fi. In this embodiment, the sensor module is configured by integrating the control plate for processing the rotation signal of the impeller Fi and the temperature sensing section.

Detected values of each flow sensor Fs, first pressure sensor Ps1, second pressure sensor Ps2, and temperature sensor Ts are input to the control device 4 . The control device 4 uses the detected values to control the operation of the electric pump 2 and the like.

<2. Operation of water supply device (see FIG. 1)>
The control device 4 can perform at least control of the electric pump 2, freeze prevention control, warning operation, etc. as the operation control of the water supply device. The control of the electric pump 2, the anti-freezing control, and the warning operation can be executed independently and in parallel.

<2.1 Control of electric pump>
The electric motor of the electric pump 2 is controlled by a pump controller via a drive circuit (not shown). The drive circuit supplies a current for driving the electric motor (hereinafter referred to as drive current) to the electric motor.

Note that the drive circuit according to the present embodiment is an inverter type drive circuit. The drive circuit supplies the electric motor with a drive current having a frequency according to the control signal transmitted from the pump control section. Hereinafter, the frequency of the drive current supplied from the drive circuit will be referred to as drive frequency.

The pump control unit according to the present embodiment is realized by executing pump control software in the control device 4 . The control device 4 is composed of a microcomputer having a CPU, ROM, RAM, and the like. The software is stored in advance in a non-volatile storage unit (not shown) such as a ROM.

The pump control unit, that is, the control device 4 can execute at least small water volume stop control, start control, and target pressure control as pump control. The small water amount stop control is a control to stop the electric pump 2 when the water supply amount becomes equal to or less than a predetermined flow rate (hereinafter referred to as stop flow rate Qo).

Incidentally, in the water supply device 1 according to this embodiment, the parallel operation control mode in which the plurality of electric pumps 2 operate together is not executed. Therefore, the water supply amount according to the present embodiment is the flow rate detected by the flow rate sensor Fs corresponding to the electric pump 2 in operation.

Startup control starts one of the electric pumps 2 when the discharge pressure P drops below a predetermined pressure (hereinafter referred to as starting pressure Po) while all the electric pumps 2 are stopped. This is the control to activate. Note that in the present embodiment, an electric pump 2 different from the electric pump 2 that was started during the previous start control is started.

The target pressure control is control for adjusting the number of revolutions of the electric pump 2 and the like so that the discharge pressure P becomes a target pressure (hereinafter referred to as target pressure Pt). Then, the target pressure Pt is determined as a function value with the detected value of the flow sensor Fs as a variable.

Specifically, the control device 4 calculates the target pressure Pt using Equation 1 below.

Pt=P2+ΔP×k̂2 Formula 1
However, ΔP = P1 = P2
k=(Q−Qo)/(Qmax−Qo)
P1, P2, Qo, Qmax: values given in advance Q: flow rate detected by flow rate sensor Fs Incidentally, P1 is the pressure when the drive frequency is maximized, that is, when the water supply amount is maximized. P2 is the pressure at the stop flow rate Qo, which is greater than the starting pressure Po. Qmax is the maximum water supply amount.

Note that FIG. 3 is an example of a flowchart showing the above-described "control of the electric pump". When a power switch (not shown) of the water supply device is turned on, the control device 4 determines whether or not the discharge pressure P is equal to or lower than the starting pressure Po (S1).

When the discharge pressure P is equal to or lower than the starting pressure Po (S1: YES), the control device 4 starts the electric pump 2 (S2), then reads the detected flow rate Q of the flow rate sensor Fs (S3), The above "k" is calculated (S4).

Next, after calculating the value of ΔP×k̂2 (S5), the control device 4 calculates the target pressure Pt (S6). Then, the control device 4 performs, for example, PID control of the drive frequency so that the discharge pressure P becomes the target pressure Pt (S7).

Next, the control device 4 determines whether or not the detected flow rate is equal to or less than the stop flow rate Qo (S8). If the detected flow rate is greater than the stop flow rate Qo (S8: NO), the controller 4 executes S3 again. If the detected flow rate is equal to or less than the stop flow rate Qo (S8: YES), the control device 4 stops the electric pump 2 (S9).

<2.2 Anti-freezing control (see Fig. 1)>
Freeze prevention control is control for preventing the water in the electric pump 2 from freezing when the electric pump 2 is stopped. Stopping and operation of the anti-freezing control is controlled by the anti-freezing control unit.

The anti-freezing control unit is realized by executing anti-freezing control software in the control device 4 . The software is stored in advance in a non-volatile storage unit (not shown) such as a ROM.

The anti-freezing control unit, that is, the control device 4, activates the anti-freezing control when the temperature detected by the temperature sensor Ts when the electric pump 2 is stopped (hereinafter referred to as the detected water temperature T) is equal to or lower than the first temperature T1.

Then, when the detected water temperature T during operation of the antifreeze control is equal to or higher than the second temperature T2, the antifreeze control is stopped. Note that the first temperature T1 and the second temperature T2 are predetermined temperatures. The second temperature T2 is a temperature higher than the first temperature T1.

Specifically, the control device 4 according to the present embodiment rotates the impeller at a predetermined rotational speed when the detected water temperature T is equal to or lower than the first temperature T1. Then, the rotation of the impeller is stopped when the detected water temperature T rises to the second temperature T2 or higher.

The control device 4 according to the present embodiment stops anti-freezing control when the push-in pressure Pp is equal to or higher than the push-in rotation pressure Pr. Specifically, when the pressing pressure Pp is equal to or higher than the pressing rotation pressure Pr, the control device 4 supplies the drive current to the electric motor of the electric pump 2 even when the detected water temperature T is equal to or lower than the first temperature T1. do not supply.

The pressing rotation pressure Pr is a predetermined pressure greater than the starting pressure Po. Specifically, it is a pushing pressure that is large enough to rotate the impeller. That is, it is a predetermined pressure equal to or higher than the value obtained by adding the pressure loss generated in the backflow prevention device 3 to the starting pressure Po.

Note that the pressure loss generated in the backflow prevention device 3 is, for example, when the flow rate of water generated when the impeller rotates at the rotation speed necessary to obtain the antifreeze effect flows through the backflow prevention device 3. This is the pressure loss that occurs in the backflow prevention device 3 .

FIG. 4 is an example of a flow chart showing the above "anti-freezing control". When the power switch (not shown) of the water supply device is turned on, the control device 4 determines whether the electric pump 2 is stopped, that is, whether the driving frequency is 0 (S11).

When it is determined that the electric pump 2 is stopped (S11: YES), the control device 4 determines whether or not the push pressure Pp is less than the push rotation pressure Pr (S12). When it is determined that the pressing pressure Pp is less than the pressing rotation pressure Pr (S12: YES), the control device 4 reads the detected water temperature T (S13).

Next, the control device 4 determines whether or not the detected water temperature T is equal to or lower than the first temperature T1 (3° C. in this embodiment) (S14). When the detected water temperature T is equal to or lower than the first temperature T1 (S14: YES), the control device 4 rotates the impeller of the electric pump 2 at a predetermined rotational speed (S15).

When the electric pump 2 is activated and anti-freezing control is activated (S15), the controller 4 reads the detected water temperature T (S16). Next, the control device 4 determines whether or not the detected water temperature T is equal to or higher than the second temperature T2 (6° C. in this embodiment) (S17).

When the detected water temperature T is equal to or higher than the second temperature T2 (S17: YES), the control device 4 stops the electric pump 2 to stop anti-freezing control (S18). When the detected water temperature T is lower than the second temperature T2 (S17: NO), the control device 4 continues the rotation of the impeller.

<2.3 Warning operation (see Fig. 1)>
The warning operation is a function of issuing a warning to that effect when it can be assumed that water leakage has occurred in the shaft seal of the electric pump 2 or the like. The warning operation is executed by the warning section.

Specifically, when the electric pump 2 is stopped, the warning unit indicates that the pushing pressure Pp is equal to or lower than the pushing rotation pressure Pr, and the detection value of the flow rate sensor Fs is a predetermined value (hereinafter referred to as leakage flow rate). .) In the above cases, a warning is issued.

Note that the warning unit is realized by executing warning software in the control device 4 . The software is stored in advance in a non-volatile storage unit (not shown) such as a ROM.

It should be noted that FIG. 5 is an example of a flow chart showing the above "warning operation". When the power switch (not shown) of the water supply device is turned on, the controller 4 determines whether the electric pump 2 is stopped (S21).

When it is determined that the electric pump 2 is stopped (S21: YES), the control device 4 reads the detected flow rate Q and the pushing pressure Pp (S22), and then the pushing pressure Pp is equal to or lower than the pushing rotational pressure Pr. And it is determined whether or not the detected flow rate Q is equal to or greater than the leakage flow rate (S23).

Then, if the state in which the pressing pressure Pp is equal to or less than the pressing rotational pressure Pr and the detected flow rate Q is equal to or greater than the leakage flow rate continues for a predetermined time (for example, 2 seconds) (S23: YES). , the control device 4 issues a water leakage warning (S24).

<3. Features of the water supply device according to the present embodiment>
The pressure of the water discharged from the electric pump 2 decreases toward the end, that is, the farther away from the electric pump. Therefore, in order to maintain the terminal pressure at the target terminal pressure, it is necessary to set the discharge pressure of the electric pump to a value equal to or higher than the sum of the pressure loss generated until the flowing water reaches the terminal.

The pressure loss changes according to the flow velocity of the running water. On the other hand, in the water supply device 1, the target pressure Pt is determined as a function value with the detection value of the flow sensor Fs as a variable, so the target pressure Pt is determined as a value according to the flow velocity of the flowing water. . Therefore, in the water supply device 1, the target pressure Pt can be determined to be an appropriate value because the pressing pressure does not affect the determination of the target pressure Pt.

The impeller Fi of the flow sensor Fs receives the dynamic pressure of the flowing water on the central axis O1 side of the imaginary line O2 (see FIG. 2). As a result, the pressure loss generated in the impeller Fi is reduced compared to a configuration in which the entire impeller Fi receives dynamic pressure.

Therefore, an increase in pressure loss is suppressed, and the energy-saving effect, which is a feature of the direct water supply system, is maintained. Since the flow rate sensor Fs can continuously detect the flow rate, it is also possible to display information such as the flow rate of each electric pump 2, the instantaneous flow rate and the integrated flow rate of the entire water supply device 1 on the control device 4 or the like. .

In the water supply device 1, when the push-in pressure Pp is equal to or higher than the push-in rotation pressure Pr, antifreeze control is stopped. This is because the impeller of the electric pump 2 can be rotated by the pushing pressure Pp when the pushing pressure Pp is greater than or equal to the pushing rotation pressure Pr.

The rotation of the impeller prevents the inside of the electric pump 2 from freezing. That is, in the water supply device 1 according to the present embodiment, freezing can be prevented without operating the electric pump 2 for anti-freezing control.

By the way, the impeller normally does not rotate when the pushing pressure Pp is equal to or lower than the pushing rotation pressure Pr in a state where no operation command is issued to the electric pump 2 . Therefore, in this case, if the detected flow rate Q is equal to or greater than a predetermined flow rate, there is a possibility that water leakage has occurred at any part of the water supply device 1 (for example, the shaft seal). expensive.

Therefore, the control device 4 issues a warning when the pushing pressure Pp is lower than the pushing rotational pressure Pr and the detected flow rate Q is higher than the leaked water flow rate in a state where the operation command to the electric pump 2 is not issued. to report.

(Other embodiments)
In the above-described embodiments, the water supply device according to the present disclosure is applied to the direct water supply device. However, the present disclosure is not so limited. That is, the disclosure is applicable to, for example, a water receiving tank type water supply apparatus.

In the above-described embodiment, the target pressure Pt is calculated using Equation 1. However, the present disclosure is not so limited. That is, the disclosure is sufficient if the target pressure Pt is determined as a function value with the detected value of the flow sensor Fs as a variable, or a function value with a parameter related to the detected value of the flow sensor Fs as a variable. is.

In the above-described embodiment, the water supply device is capable of anti-freezing control and warning operation. However, the present disclosure is not so limited. That is, the disclosure includes, for example, a configuration in which at least one function of anti-freezing control and warning operation is abolished, or a function of at least one of anti-freezing control and warning operation, and detection of the flow sensor Fs The configuration may be such that the function of determining the target pressure Pt using the value is abolished.

In the above-described embodiment, the flow sensor Fs is arranged on the suction side of the electric pump 2 . However, the present disclosure is not so limited. That is, the disclosure may be configured such that the flow rate sensor Fs is disposed on the discharge side of the electric pump 2, for example.

In the anti-freezing control according to the above embodiment, freezing is prevented by rotating the impeller when the detected water temperature T is equal to or lower than the first temperature T1. However, the present disclosure is not so limited. That is, the disclosure may include a heater that heats the pump housing of the electric pump when the detected water temperature T is equal to or lower than the first temperature T1, for example.

Furthermore, the present disclosure is not limited to the above-described embodiments as long as it conforms to the gist of the disclosure described in the above-described embodiments. Therefore, in the configuration in which at least two of the above-described embodiments are combined, or in the above-described embodiments, any one of the illustrated constituent elements or the constituent elements described with reference numerals is abolished. It may be a configuration that is

REFERENCE SIGNS LIST 1 water supply device 2 electric pump 3 backflow prevention device 4 control device Fs flow rate sensor Ps1 first pressure sensor Ps2 second pressure sensor Ts temperature sensor

Claims (6)

In a water supply device equipped with an electric pump,
a flow sensor capable of continuously detecting the amount of water supply;
a pressure sensor that detects the discharge side pressure of the electric pump;
a control unit capable of executing target pressure control using the detected value of the flow rate sensor and the detected value of the pressure sensor;
When the value determined as a function value with the detected value of the flow sensor as a variable is the target pressure,
In the target pressure control, the electric pump is controlled such that the detected value of the pressure sensor becomes the target pressure. A backflow prevention device provided on the suction side of the electric pump, the backflow prevention device having an inflow side connected to a water pipe,
2. The water supply system according to claim 1, wherein said flow rate sensor is arranged in a flowing water passage between said backflow prevention device and said electric pump. The flow sensor has an impeller that rotates around a virtual line parallel to a direction orthogonal to the central axis of the flowing water passage,
The water supply device according to claim 1 or 2, wherein the impeller receives dynamic pressure of flowing water on the central axis side of the imaginary line. A water supply device comprising an electric pump having a rotating impeller, wherein the suction side of the electric pump is connected to a water pipe,
a backflow prevention device provided on the suction side of the electric pump;
a pressure sensor that detects water pressure;
A pump control unit that controls the stop and operation of the electric pump, wherein when the pressure detected by the pressure sensor when the electric pump is stopped falls below a predetermined pressure (hereinafter referred to as starting pressure) a pump control unit capable of executing activation control for activating the electric pump;
an antifreeze control unit that controls the stoppage and operation of antifreeze control that prevents the water in the electric pump from freezing when the electric pump is stopped;
When the pressure detected by the pressure sensor when the electric pump is stopped is defined as a pressing pressure, and a predetermined pressure greater than the starting pressure is defined as a pressing rotation pressure,
The anti-freezing control unit stops the anti-freezing control when the pressing pressure is equal to or higher than the pressing rotation pressure. a flow sensor capable of continuously detecting the amount of water supply;
and a warning unit that issues a warning when the pushing pressure is equal to or lower than the pushing rotation pressure and the detection value of the flow rate sensor is equal to or higher than a predetermined value when the electric pump is stopped. The water supply device described in . Equipped with a temperature sensor that detects water temperature,
The anti-freeze control unit is
operating the antifreeze control when the temperature detected by the temperature sensor when the electric pump is stopped is equal to or lower than a predetermined first temperature;
The water supply device according to claim 4 or 5, wherein the antifreeze control is stopped when the water temperature detected during operation of the antifreeze control is equal to or higher than a predetermined second temperature higher than the first temperature.

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