JP7555563B2 - Water supply equipment - Google Patents

Description

The present invention relates to a water supply device equipped with multiple pump devices.

When the temperature of the flow passages in a water supply device drops due to a drop in the outside air temperature, a technology is known in which the pump device is operated to increase the temperature in the flow passages, thereby preventing the water in the flow passages in the water supply device from freezing.

Japanese Patent Application Publication No. 10-169568

Some of these water supply systems are equipped with multiple pump devices. For example, in the case of alternating operation, depending on the operating method, there are cases where multiple pump devices are operated simultaneously because the priority is given to preventing freezing.

The present invention aims to provide a water supply device that reliably operates in alternating fashion even during freeze prevention operation and is more energy efficient than a heater that is externally attached to the pump.

A water supply apparatus according to one embodiment of the present invention comprises a plurality of pump devices each including a pump and a motor for driving the pump; a temperature detection device; and a control unit which controls the motor and transitions an operation mode of the motor from a normal operation mode to a freeze prevention operation mode when a temperature detected by the temperature detection device becomes less than a first threshold value, transitions the operation mode from the freeze prevention operation mode to the normal operation mode when a temperature detected by the temperature detection device becomes equal to or greater than a second threshold value that is greater than the first threshold value, and drives the motor at preset constant on time intervals and off time intervals during the freeze prevention operation mode, thereby alternately operating the plurality of pumps ;
The control unit has an internal memory unit, and during the freeze prevention operation mode, stores in the internal memory unit the detected temperature of the temperature detection device immediately before the motor is turned off.If it determines that the stored detected temperature is less than the detected temperature stored previously immediately before the motor is turned off, it increases the frequency of the AC power supply supplied the next time the motor is turned on .

According to the present invention, by reliably operating alternately even during freeze prevention operation, in the case of pumps that operate alternately during normal operation, simultaneous operation of multiple pumps can be suppressed even during freeze prevention operation. In addition, a water supply device that is more energy efficient than when using a heater external to the pump can be provided.

1 is an explanatory diagram showing the configuration of a water supply device according to one embodiment of the present invention; 4 is a flowchart showing an example of the operation of the water supply device. FIG. 11 is a front view showing a configuration of a modified example of the water supply device.

Below, a water supply device 10 according to one embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig. 1 is an explanatory diagram showing the configuration of the water supply device 10. Fig. 2 is a flow chart showing an example of the operation of the water supply device 10.

As shown in FIG. 1, the water supply device 10 includes a plurality of pump devices 20, a discharge pipe 25, a pressure sensor 30, a flow rate sensor 40, an inverter 50 connected to the motor 22 of each pump device 20, a temperature detection device 60, and a control panel 90 including a memory unit 91 and a control unit 92.

In this embodiment, the water supply device 10 includes, as an example, two pump devices 20. Each of the multiple pump devices 20 includes a pump 21 and a motor 22. The pump device 20 pressurizes the water and pumps it to the secondary side.

The pump 21 includes, for example, one or more impellers, a rotating shaft provided on the impeller, and a casing in which the impeller is disposed. The casing includes a pump suction port and a pump discharge port. The pump suction port is fluidly connected to a water pipe, a well, a water tank, or the like via a suction pipe. The pump discharge port is connected to a discharge pipe 25.

The motor 22 is fixed to the impeller's rotating shaft and rotates the impeller. The motor 22 is connected to the control unit 92 in the control panel 90 by a cable.

The discharge piping 25 includes a plurality of individual discharge pipes 26 and a junction pipe 27. The plurality of individual discharge pipes 26 are connected to the discharge ports of the plurality of pumps 21. The junction pipe 27 is where the plurality of individual discharge pipes 26 join together. The secondary side of the junction pipe 27 is connected to the water supply device to which water is to be supplied.

The pressure sensor 30 is provided, for example, in the junction pipe 27. The pressure sensor 30 is connected to the control unit 92 via a signal line and transmits a signal corresponding to the pressure to the control unit 92.

A flow sensor 40 is provided in each individual discharge pipe 26. The flow sensor 40 is configured to be able to detect the stop flow rate. The flow sensor 40 is a proximity sensor that includes, for example, a paddle with a magnet, and detects the flow rate using a Hall IC or the like when the magnet is brought close. The flow sensor 40 is connected to the control unit 92 via a signal line, and transmits a signal to the control unit 92 when it detects, for example, the stop flow rate.

An inverter 50 is provided in each pump device 20. The inverter 50 is electrically connected to the motor 22 of each pump device 20. The inverter 50 outputs a voltage of a predetermined frequency according to a control signal from the control unit 92, thereby rotating the connected motor 22.

The temperature detection device 60 is configured to be able to detect the temperature of a portion where the temperature changes in relation to the water temperature of the multiple pumps 21 and the discharge pipe 25, which is the secondary flow path of the multiple pumps 21, by the control unit 92. That is, the temperature of the location where the temperature detection device 60 is provided is a predetermined temperature relative to the temperature of the water in the multiple pumps 21 and the discharge pipe 25. In other words, it is possible to estimate the temperature of the water in the multiple pumps 21 and the discharge pipe 25 from the temperature detected by the temperature detection device 60. The temperature detection device 60 is provided in the multiple inverters 50, the multiple pump devices 20, the secondary flow paths of the multiple pump devices 20, or outside the multiple pump devices 20.

For example, two temperature detection devices 60 are provided. As an example, each of the two temperature detection devices 60 is provided in the inverter 50. The temperature detection devices 60 are connected to the control unit 92 and transmit a signal corresponding to the detected temperature to the control unit 92. The temperature detection devices 60 are, for example, thermistors. In this embodiment, as an example, the temperature detection devices 60 detect the temperature of the inverter 50. That is, the detected temperature TH of the temperature detection devices 60 is the temperature of the inverter 50 in this embodiment.

The control panel 90 includes a circuit board on which a memory unit 91 and a control unit 92 are mounted. In this embodiment, the memory unit 91 is, for example, a so-called internal control unit memory unit mounted on the circuit board that constitutes the control unit 92.

The memory unit 91 is a storage device equipped with, for example, a program memory, a RAM, and a rewritable ROM. The memory unit 91 sets and stores a first threshold value T1, a second threshold value T2, an on-time T3 which is the driving time of the motor 22 in the freeze prevention operation mode, and an off-time T4 which is the time when the driving of the motor 22 is stopped in the freeze prevention operation mode. Here, the freeze prevention operation mode is a continuous shut-off operation of the pump device 20 to prevent the pump 21 and the water in the piping from freezing. In addition, the freeze prevention operation is an operation in which one motor 22 and the other motor 22 are alternately driven and stopped.

Here, the piping refers to the piping that constitutes the secondary flow path of the pump 21 provided in the water supply device 10, and in this embodiment, an example is the discharge piping 25.

The first threshold T1 is a detection temperature used to determine the start of the transition from the normal operation mode to the freeze prevention operation mode. The first threshold T1 is compared with the detection temperature TH of the temperature detection device 60. The first threshold T1 is the detection temperature of the temperature detection device 60 when there is a risk of the water in the multiple pumps 21 and the discharge pipes 25 freezing.

The temperature detected by the temperature detection device 60 when there is a risk of the water in the multiple pumps 21 and the discharge pipe 25 freezing is, for example, the temperature at which the outside air temperature freezes the water in the multiple pumps 21 and the discharge pipe 25, and is the temperature detected by the temperature detection device 60 when the water in the multiple pumps 21 and the discharge pipe 25 freezes if the multiple pump devices 20 continue to be in a non-operated state. The first threshold T1 is, for example, 2 degrees or 3 degrees. Note that the first threshold T1 can be set appropriately.

The second threshold T2 is a detection temperature that determines whether to end the freeze prevention operation mode and return to the normal operation mode. The second threshold T2 is compared with the detection temperature TH of the temperature detection device 60. The second threshold T2 is set to a temperature higher than the first threshold T1. The second threshold T2 is, for example, 5 degrees or 6 degrees.

The on-time T3 for operation in anti-freeze operation mode is, for example, 1 minute.

The off time T4 for operation in the freeze prevention operation mode is set to be equal to or longer than the on time T3. The off time T4 is, for example, one minute.

The control unit 92 includes, for example, a processor. The control unit 92 estimates the temperature of the multiple pumps 21 and the water in the discharge piping 25 based on the detected temperature TH of the temperature detection device 60. For example, the memory unit 91 has a map that links the detected temperature TH of the temperature detection device 60 and the water temperatures of the multiple pumps 21 and the secondary side discharge piping 25 from actual measurement results. Then, the control unit 92 estimates the temperature of the multiple pumps 21 and the water in the piping based on the detected temperature TH of the temperature detection device 60 and the map of the memory unit 91.

In this way, by being able to estimate the temperature of the water in the multiple pumps 21 and the discharge pipe 25, it is possible to control the water supply device 10 at a temperature where the water in the multiple pumps 21 and the discharge pipe 25 do not freeze. Therefore, there is no restriction on the location where the temperature detection device 60 can be installed.

The control unit 92 also controls the multiple pump devices 20 in accordance with a program prestored in the memory unit 91 based on signals from the pressure sensor 30, the flow sensor 40, and the temperature detection device 60. Specifically, the control unit 92 controls the multiple inverters 50 by transmitting control signals to the multiple inverters 50. The control unit 92 controls the multiple pump devices 20 in the normal operation mode, for example, by constant target pressure control.

When the control unit 92 determines from the detection result of the flow rate sensor 40 that water is not being supplied to the water supply destination, it transitions from the normal operation mode to the freeze prevention operation mode based on the temperature TH detected by the temperature detection device 60. In other words, it transitions to the freeze prevention operation mode, which is a shut-off operation.

In this embodiment, when determining whether water is not being supplied to the water supply destination, for example, when the motors 22 of all pump devices 20 provided in the water supply device 10 are turned off, i.e., stopped, it is determined that water is not being supplied to the water supply destination.

In this embodiment, when the motors 22 of the two pump devices 20 are turned off, i.e., stopped, and the detected temperature TH of the temperature detection device 60 falls below the first threshold value T1, the operation mode transitions from normal operation mode to anti-freeze operation mode, and the pump devices 20 are operated in the anti-freeze operation mode. When the two pump devices 20 are operated in the anti-freeze operation mode, the control unit 92 alternately operates the motors 22 of the two pump devices 20. Specifically, while driving the motor 22 of one pump device 20 for the drive time stored in the memory unit 91, the motor 22 of the other pump device 20 is stopped for the stop time stored in the memory unit 91.

Next, an example of the control of the water supply device 10 will be described with reference to FIG. 2. Here, one of the two pump devices 20 is the first pump device 20A, and the other is the second pump device 20B. The pump 21 of the first pump device 20A is the first pump 21A, and the pump 21 of the second pump device 20B is the second pump 21B. The motor 22 of the first pump device 20A is the first motor 22A, and the motor 22 of the second pump device 20B is the second motor 22B. The inverter 50 connected to the first motor 22A is the first inverter 50A, and the inverter 50 connected to the second motor 22B is the second inverter 50B. The temperature detection device 60 provided in the first inverter 50A is the first temperature detection device 60A, and the temperature detection device 60 provided in the second inverter 50B is the second temperature detection device 60B. In addition, the detection temperature of the first temperature detection device 60A is set to detection temperature TH1, and the detection temperature of the second temperature detection device 60B is set to detection temperature TH2.

The control unit 92 controls the normal operation mode by constant target pressure control, such as constant discharge pressure control and constant estimated end pressure control, based on the flow rate and pressure detected by the flow rate sensor 40 and pressure sensor 30. The control unit 92 operates the first pump device 20A and the second pump device 20B by outputting control signals to each inverter 50.

The control unit 92 further estimates the water temperature of the first pump 21A and the discharge pipe 25, and the water temperature of the second pump 21B and the discharge pipe 25, based on the detected temperatures TH1 and TH2 of the first temperature detection device 60A and the second temperature detection device 60B. The control unit 92 also controls the multiple pump devices 20 in the freeze prevention operation mode based on the detected temperatures TH1 and TH2 of the first temperature detection device 60A and the second temperature detection device 60B.

2, with the operation of the first pump device 20A and the second pump device 20B stopped, the control unit 92 estimates the temperature of the water in the piping including the first pump 21A and the discharge piping 25 based on the signal from the first temperature detection device 60A, and determines whether the detected temperature TH1 of the first temperature detection device 60 is less than the first threshold value T1 (step ST1). If the detected temperature TH1 is equal to or greater than the first threshold value T1 (NO in step ST1), the control unit 92 maintains the stopped state of the first pump device 20A and stops operation in the freeze prevention operation mode (step ST2).

In parallel with the processing of step ST1, the control unit 92 estimates the temperature of the water in the piping including the second pump 21B and the discharge piping 25 based on the detected temperature TH2 of the second temperature detection device 60B, and determines whether the detected temperature TH2 of the second temperature detection device 60B is less than the first threshold value T1 (step ST3). If the detected temperature TH2 is equal to or greater than the first threshold value T1 (NO in step ST3), the control unit 92 keeps the second pump device 20B stopped and stops the anti-freeze operation (step ST4).

When the control unit 92 determines that the detected temperature TH1 is less than the first threshold T1 (YES in step ST1), it then determines whether the detected temperature TH2 of the second temperature detection device 60B is less than the first threshold T1 (step ST5).

When the control unit 92 determines that the detected temperature TH2 is equal to or higher than the first threshold value T1 (NO in step ST5), it determines the first pump unit 20A as the pump unit to be operated in the freeze prevention operation mode (step ST6).

When the control unit 92 determines that the detected temperature TH2 is less than the first threshold value T1 (YES in step ST5), it determines the first pump unit 20A and the second pump unit 20B as the pump units to be operated in the freeze prevention operation mode.

In addition, when the control unit 92 determines in step ST3 that the detected temperature TH2 is less than the first threshold value T1 (YES in step ST3), it determines whether the detected temperature TH1 of the first temperature detection device 60A is less than the first threshold value T1 (step ST8).

When the control unit 92 determines that the detected temperature TH1 is equal to or higher than the first threshold value T1 (NO in step ST8), it determines the second pump unit 20B as the pump unit to be operated in the freeze prevention operation mode (step ST9).

When the control unit 92 determines that the detected temperature TH2 is less than the first threshold value T1 (YES in step ST8), it determines the first pump unit 20A and the second pump unit 20B as the pump units to be operated in the freeze prevention operation mode (step ST7).

When the control unit 92 determines that only the first pump unit 20A is to operate in the freeze prevention operation mode, it starts operation of the first pump unit 20A in the freeze prevention operation mode (step ST10).

The control unit 92 controls the first motor 22A by constant frequency control (step ST11). Here, constant frequency control is a control in which the frequency of the AC power source supplied to the motor 22 is kept constant. In this embodiment, a voltage of the minimum operating frequency is supplied. The minimum operating frequency is the minimum frequency required to drive the motor 22. In addition, the control unit 92 prohibits the driving of the second motor 22B while driving the first motor 22A.

The control unit 92 sets and stores the detected temperature TH1 of the first temperature detection device 60A in the memory unit 91 just before the drive time of the first motor 22A elapses the on-time T3 set and stored in the memory unit 91, i.e., just before turning off. Here, just before the on-time T3 elapses, i.e., just before turning off, is, for example, 1 second before the on-time T3 elapses, and can be set appropriately.

Then, when the drive time of the first motor 22A reaches the on-time T3 set and stored in the memory unit 91, the control unit 92 stops the drive of the first motor 22A. Then, the control unit 92 releases the prohibition on the operation of the second pump device 20B (step ST12).

Next, the control unit 92 determines whether the detection temperature TH1 immediately before the previous turn-off stored in the memory unit 91 is equal to or higher than the detection temperature TH1 immediately before the current turn-off stored (step ST13).

When the control unit 92 determines that the temperature TH1 detected immediately before the previous off-state is equal to or higher than the temperature TH1 detected immediately before the current off-state (YES in step ST13), the control unit 92 increases the frequency of the AC power supplied to the first motor 22A at a preset rate when the first motor 22A is next driven in the freeze prevention operation mode of the first pump device 20A (step ST14). The increase amount is, for example, 1 Hz. Note that the upper limit of the power frequency supplied to the first motor 22A in the freeze prevention operation mode is the shut-off operation frequency detected during the target pressure constant control. When the power frequency supplied to the first motor 22A becomes the shut-off operation frequency, the control unit 92 stops increasing the frequency and supplies power at the shut-off operation frequency.

When the control unit 92 determines that the temperature TH1 detected immediately before the previous turn-off is lower than the temperature TH1 detected immediately before the current turn-off (NO in step ST13), it maintains the power frequency supplied to the first motor 22A the next time the first motor 22A is driven while the first pump device 20A is operating in the freeze prevention operation mode (step ST15).

Next, the control unit 92 estimates the temperature of the water in the first pump 21A and the discharge pipe 25 based on the signal from the detection temperature TH1 of the first temperature detection device 60A, and determines whether the detection temperature TH1 is less than the second threshold value T2 (step ST16).

When the control unit 92 determines that the detected temperature TH1 is less than the second threshold value T2 (YES in step ST16), it returns to step ST11 and drives the first motor 22A.

When the control unit 92 determines that the temperature TH1 is equal to or greater than the second threshold value T2 (NO in step ST16), it proceeds to step ST2 and stops operation in the freeze prevention operation mode.

When the control unit 92 determines that only the second pump unit 20B is to operate in the freeze prevention operation mode, it starts operation of the first pump unit 20A in the freeze prevention operation mode (step ST17).

The control unit 92 controls the second motor 22B by constant frequency control (step ST18). In this embodiment, a voltage of the minimum operating frequency is supplied. In addition, the control unit 92 prohibits the driving of the first motor 22A while driving the second motor 22B.

The control unit 92 sets and stores the detected temperature TH2 of the second temperature detection device 60B in the memory unit 91 just before the drive time of the second motor 22B elapses the on-time T3 set and stored in the memory unit 91, i.e., just before turning off. Here, just before the on-time T3 elapses, i.e., just before turning off, is, for example, 1 second before the on-time T3 elapses, and can be set appropriately.

Then, when the drive time of the second motor 22B reaches the on-time T3 set and stored in the memory unit 91, the control unit 92 stops the drive of the second motor 22B. Then, the control unit 92 releases the drive prohibition of the first motor 22A (step ST19).

Next, the control unit 92 determines whether the detection temperature TH2 immediately before the previous off-time stored in the memory unit 91 is equal to or higher than the detection temperature TH2 immediately before the off-time stored this time (step ST20).

When the control unit 92 determines that the temperature TH2 detected immediately before the previous off-state is equal to or higher than the temperature TH2 detected immediately before the current off-state (YES in step ST20), the control unit 92 increases the frequency of the voltage supplied to the second motor 22B at a preset rate the next time the second motor 22B is driven in the freeze prevention operation mode of the second pump device 20B (step ST21). The increase amount is, for example, 1 Hz. When the power frequency supplied to the second motor 22B becomes the shut-off operation frequency, the control unit 92 stops increasing the frequency and supplies power at the shut-off operation frequency.

When the control unit 92 determines that the temperature TH2 detected immediately before the previous turn-off is lower than the temperature TH2 detected immediately before the current turn-off (NO in step ST19), it maintains the power frequency supplied to the second motor 22B the next time the second motor 22B is driven during the freeze prevention operation of the second pump device 20B (step ST22).

Next, the control unit 92 estimates the temperature of the water in the second pump 21B and the discharge pipe 25 based on the detected temperature TH2 of the second temperature detection device 60B, and determines whether the detected temperature TH2 is less than the second threshold value T2 (step ST23).

When the control unit 92 determines that the detected temperature TH2 is less than the second threshold T2 (YES in step ST22), the control unit 92 returns to step ST18 and continues operation in the anti-freeze operation mode. When the control unit 92 determines that the detected temperature TH2 is equal to or greater than the second threshold T2 (NO in step ST22), the control unit 92 returns to step ST4 and stops operation in the anti-freeze operation mode.

When the control unit 92 determines that the first pump unit 20A and the second pump unit 20B are to be operated in the freeze prevention operation mode (step ST7), it compares the detected temperature TH1 with the detected temperature TH2 and determines whether the detected temperature TH1 is equal to or lower than the detected temperature TH2 (step ST24).

When the control unit 92 determines that the detected temperature TH1 is equal to or lower than the detected temperature TH2 (YES in step ST24), the control unit 92 operates the first pump unit 20A as the leading pump and the second pump unit 20B as the trailing pump in an anti-freeze operation mode by alternating between the first pump unit 20A and the second pump unit 20B (steps ST10 and ST17).

Specifically, while driving the first motor 22A, the control unit 92 stops the second motor 22B, and while driving the second motor 22B, the control unit 92 stops the first motor 22A. In other words, while performing the process of step ST11 on the first pump device 20A, the control unit 92 performs the process of step ST19 on the second pump device 20B. Furthermore, while performing the process of step ST12 on the first pump device 20A, the control unit 92 performs the process of step ST18 on the second pump device 20B.

When the control unit 92 determines that the detected temperature TH1 is higher than the detected temperature TH2 (NO in step ST24), the control unit 92 sets the second pump unit 20B as the leading pump and the first pump unit 20A as the trailing pump, and operates the first pump unit 20A and the second pump unit 20B in an anti-freeze operation mode by alternating operation (steps ST10 and ST17).

Specifically, the control unit 92 stops the first motor 22A while driving the second motor 22B, and stops the second motor 22B while driving the first motor 22A. In other words, the control unit 92 performs the process of step ST12 on the first pump device 20A while performing the process of step ST18 on the second pump device 20B. Furthermore, the control unit 92 performs the process of step ST11 on the first pump device 20A while performing the process of step ST19 on the second pump device 20B.

In the water supply system 10 configured in this manner, when only one pump device 20 is operated in the freeze prevention operation mode, the motor 22 of this pump device 20 is alternately driven and stopped. Therefore, by ensuring alternating operation even during freeze prevention operation, in the case of pumps that alternate during normal operation, simultaneous operation of multiple pumps can be suppressed even during freeze prevention operation. In addition, energy savings are greater than when using a heater external to the pump.

Furthermore, in the water supply device 10, by setting the off time T4 of the motor 22 in the freeze prevention operation mode to be equal to or longer than the on time T3, when two pump devices 20 are operated in the freeze prevention operation mode, it is possible to alternately operate the motor 22 of one pump device 20 and the motor 22 of the other pump device 20. As a result, the two water supply devices 10 are not operated at the same time, and by reliably operating alternately even during freeze prevention operation, in the case of pumps that operate alternately during normal operation, multiple pumps are not operated simultaneously even during freeze prevention operation. In addition, energy savings are greater than when using a heater external to the pump.

Furthermore, when the control unit 92 is operating in the freeze prevention operation mode, if the temperature TH detected by the temperature detection device 60 immediately before the motor 22 is turned off is less than the temperature TH detected immediately before the previous time it was turned off that is set and stored in the memory unit 91, the control unit 92 increases the power frequency supplied when the motor 22 is next turned on. As a result, the rotation speed of the motor 22 increases, and the heat generation amount of the pump 21 increases. As a result, if this circulation operation is continued, the temperature TH detected immediately before the temperature detection device 60 is turned off can be prevented from becoming less than the temperature TH detected immediately before the previous time it was turned off that is stored in the memory unit 91, and therefore the pump 21 and the piping including the discharge piping 25 can be prevented from freezing.

Furthermore, during anti-freeze operation, the control unit 92 sets the upper limit of the power frequency supplied to the motor 22 of the pump device 20 to the frequency during shut-off operation, thereby preventing power consumption during anti-freeze operation from increasing.

In the above example, the control unit 92 has been described as being configured to change the power frequency supplied to the motor 22 during operation in the freeze prevention operation mode within a range from the minimum frequency to the shut-off operation frequency detected during constant target pressure control, but this is not limited to this. In other examples, the control unit 92 may drive the motor 22 under constant target pressure control even during freeze prevention operation.

Alternatively, the control unit 92 may calculate the power consumption during operation in the anti-freeze operation mode, and control the voltage and current supplied to the motor 22 so that the power consumption during anti-freeze operation does not exceed a predetermined upper limit. Specifically, the memory unit 91 stores a first upper limit T5, which is the upper limit of the power supplied to the motor 22 during anti-freeze operation. The control unit 92 controls the voltage and current supplied to the motor 22 so that the power consumption, i.e., the power supplied to the motor 22, does not exceed the first upper limit T5, in other words, controls the power supplied to the motor 22 to be equal to or less than the first upper limit T5.

Alternatively, the water supply device 10 may control the current supplied to the motor 22 during operation in the freeze prevention operation mode so that the current supplied to the motor 22 does not exceed a predetermined upper limit. Specifically, the memory unit 91 stores a second upper limit value T6, which is the upper limit value of the current supplied to the motor 22 during operation in the freeze prevention operation mode. The control unit 92 controls the current supplied to the motor 22 during freeze prevention operation so that it does not exceed the second upper limit value T6, in other words, controls the current supplied to the motor 22 to be equal to or less than the second upper limit value T6.

Alternatively, the memory unit 91 stores the first upper limit value T5 and the second upper limit value T6, and the control unit 92 controls the voltage and current supplied to the motor 22 during operation in the freeze prevention operation mode so that the power consumption, i.e., the power supplied to the motor 22, does not exceed the first upper limit value T5, in other words, controls the power supplied to the motor 22 to be equal to or less than the first upper limit value T5, and controls the current supplied to the motor 22 during operation in the freeze prevention operation mode so that it does not exceed the second upper limit value T6, in other words, controls the current supplied to the motor 22 to be equal to or less than the second upper limit value T6.

In the above example, the control unit 92 compares the detected temperature TH of the temperature detection device 60 provided in the inverter 50 with the threshold values T1 and T2, and further estimates the temperature of the water in the pump 21 and the discharge pipe 25 based on the detected temperature TH1. However, the present invention is not limited to this.

In another example, the temperature detection device 60 may be provided directly on the pump 21. Or, the temperature detection device 60 may be provided directly on the secondary flow path of the pump 21. As an example of this, the temperature detection device 60 may be provided on the individual discharge pipe 26. Or, the temperature detection device 60 may be provided outside both the pump 21 and the secondary flow path of the pump 21, at a position where the control unit 92 can detect the temperature of the water on the secondary side of the pump 21.

In the above example, the water supply device 10 includes two pump devices 20 as the multiple pump devices 20, and in the freeze prevention operation mode, one pump device 20 and the other pump device 20 are alternately operated. However, this is not limiting. In another example, the water supply device 10 may include three or more pump devices 20. In the case of a configuration including three or more pump devices 20, in the freeze prevention operation mode, the multiple pump devices 20 may be alternately operated by driving one pump device 20 and stopping the other pump devices 20.

Alternatively, when the water supply device 10 is configured to have three or more pump devices 20, the control unit 92 divides these three or more pump devices 20 into pairs or into single units. For example, in a configuration with an odd number of pump devices 20, for example three pump devices 20, they are divided into a set of two pump devices 20 and one pump device 20. For example, in a configuration with an even number of pump devices 20, for example four pump devices 20, they are divided into two sets of two pump devices 20. Five pump devices 20 are divided into two sets of two pump devices 20 and one pump device 20. The control unit 92 then sets the first pump device 20A and the second pump device 20B for these divided pump devices 20, respectively, and performs the control shown in FIG. 2. Note that only one pump device 20 is set, for example, to the first pump device 20A.

In this way, by dividing the multiple pump devices 20 into pairs or into single pump devices 20 and performing the control shown in Figure 2 for each, it is possible to have one type of program for performing anti-freeze operation for the multiple pump devices 20 provided in the water supply device 10.

In other words, by using one type of program that can perform anti-freeze operation on up to two pump devices 20 simultaneously, it is possible to perform anti-freeze operation on three or more pump devices 20.

Therefore, there is no need to prepare a program according to the number of pump devices 20 that will perform anti-freeze operation. Furthermore, by making the program for anti-freeze operation a program that simultaneously performs anti-freeze operation on up to two pump devices 20, it is possible to prevent the program from becoming complicated.

The water supply device 10 may also be configured to include a heat insulating material 100 that covers the pump 21 and at least one of the secondary flow paths of the pump 21. As an example, as shown in FIG. 3, the water supply device 10 includes a heat insulating material 100 that covers the individual discharge pipe 26, which is the secondary flow path of the pump 21. The heat insulating material 100 is made of, for example, polystyrene foam.

By covering at least one of the pump 21 and the flow path on the secondary side of the pump 21 with the thermal insulation material 100, the water on the secondary side of the pump 21 is kept warm. This reduces the frequency of anti-freeze operation and also reduces the power supply frequency when operating in anti-freeze operation mode, thereby further reducing power consumption due to anti-freeze operation.

In another example, the heat-insulating material 100 may be provided on the pump 21 and configured to cover the pump 21. Alternatively, the heat-insulating material 100 may be provided on both the pump 21 and the secondary flow path of the pump 21 and configured to cover both the pump 21 and the secondary flow path of the pump 21.

The present invention is not limited to the above-described embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. The embodiments may be implemented in appropriate combination, in which case the combined effects can be obtained. Furthermore, the above-described embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple constituent elements disclosed. For example, if the problem can be solved and an effect can be obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the configuration from which these constituent elements are deleted can be extracted as an invention.

10...water supply device, 20...pump device, 20A...first pump device, 20B...second pump device, 21...pump, 21A...first pump, 21B...second pump, 22...motor, 22A...first motor, 22B...second motor, 25...discharge pipe, 26...individual discharge pipe, 27...junction pipe, 30...pressure sensor, 40...flow sensor, 50...inverter, 50A...first inverter, 50B...second inverter, 60...temperature detection device, 60A...first temperature detection device, 60B...second temperature detection device, 90...control panel, 91...memory unit, 92...control unit, 100...thermal insulation.

Claims (7)

A plurality of pump devices each including a pump and a motor for driving the pump;
A temperature detection device;
a control unit that controls the motor, transitioning an operation mode of the motor from a normal operation mode to a freeze prevention operation mode when a temperature detected by the temperature detection device becomes lower than a first threshold, transitioning the operation mode from the freeze prevention operation mode to the normal operation mode when the temperature detected by the temperature detection device becomes equal to or higher than a second threshold that is higher than the first threshold, and driving the motor at preset constant on-time intervals and off-time intervals during the freeze prevention operation mode, thereby alternately operating the multiple pumps;
Equipped with
The control unit has an internal memory unit, and during the freeze prevention operation mode, stores in the internal memory unit the detected temperature of the temperature detection device just before the motor is turned off, and when it determines that the stored detected temperature is lower than the detected temperature stored previously just before the motor is turned off, increases the frequency of the AC power supply supplied the next time the motor is turned on . A plurality of pump devices each including a pump and a motor for driving the pump;
A temperature detection device;
a control unit that controls the motor, transitioning an operation mode of the motor from a normal operation mode to a freeze prevention operation mode when a temperature detected by the temperature detection device becomes lower than a first threshold, transitioning the operation mode from the freeze prevention operation mode to the normal operation mode when the temperature detected by the temperature detection device becomes equal to or higher than a second threshold that is higher than the first threshold, and driving the motor at preset constant on time intervals and off time intervals during the freeze prevention operation mode;
Equipped with
the off-time of the motor during the freeze prevention operation mode is set to be equal to or greater than the on-time of the motor;
the control unit divides the plurality of pump devices into pairs and one pump device group when the number of the plurality of pump devices is an odd number, and divides the plurality of pump devices into pairs of pump device groups when the number of the plurality of pump devices is an even number, and alternately operates the pumps in the pair of pump devices such that while one of the motors in the pair of pump devices is being driven, the drive of the other motor is stopped ;
The control unit has an internal memory unit, and during the freeze prevention operation mode, stores in the internal memory unit the detected temperature of the temperature detection device just before the motor is turned off, and when it determines that the stored detected temperature is lower than the detected temperature stored previously just before the motor is turned off, increases the frequency of the AC power supply supplied the next time the motor is turned on . A water supply system as described in claim 1 or claim 2, wherein the control unit controls the multiple pump devices using constant target pressure control in the normal operation mode, and in the freeze prevention operation mode, the initial value of the frequency of the AC power supply supplied to the motor is the minimum operating frequency, and the upper limit value is the frequency during shut-off operation using the constant target pressure control. The water supply device according to claim 1 or 2, wherein the control unit operates the pump device in which the motor is driven in the freeze prevention operation mode under constant target pressure control. the control unit storage unit stores at least one of a first upper limit value as an upper limit value of power supplied to the motor in the freeze prevention operation mode and a second upper limit value as an upper limit value of current supplied to the motor in the freeze prevention operation mode;
The control unit sets the power supplied to the motor during the freeze prevention operation mode to be equal to or less than the first upper limit value, or sets the current supplied to the motor during the freeze prevention operation mode to be equal to or less than the second upper limit value.
A water supply device according to claim 1 or 2. a plurality of inverters each supplying power to the motor of each of the plurality of pump devices;
3. The water supply apparatus according to claim 1, wherein the temperature detection device is provided in the inverters, the pump devices, a secondary flow path of the pump devices, or outside the pump devices. The water supply device according to claim 1 or 2, further comprising a heat insulating material provided in at least one of the pumps and the secondary flow paths of the plurality of pump devices.