JP2004084582A - Variable speed water-supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable speed water-supply device that inhibits pressure fluctuation of water by the demand side, and reduces the starting frequency of a pump. <P>SOLUTION: The watering device having the pump 12, a discharge pipe 14, a pressure tank 16, a check valve 18, a pressure detection means 20, a motor 22 and a control means 24, comprises a minimum water amount detection means 26 for detecting that the water amount in the discharge pipe 14 has reached a predetermined minimum water amount, a pressure setting means 28 that arbitrarily sets, from the outside, higher-limit pressure PA and lower-limit pressure PB as a parameter for sequentially calculating estimated terminal pressure, and a pressure calculating means 32 that calculates stop pressure of the pump 12 based on the higher-limit pressure PA and the lower-limit pressure PB and calculates start pressure of the pump based on the stop pressure. The control means 24 is configured to receive a detection signal from the detection means 26 when the water amount has reached the minimum water amount and temporarily sets discharge pressure of the pump to the stop pressure instead of target pressure so that the motor 22 is stopped after a predetermined time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable speed water supply device, and more particularly to a variable speed water supply device of an underwater quantity stop type.
[0002]
[Prior art]
Generally, the pressure in the piping installed on the discharge side of the water supply device is kept as constant as possible to suppress a temperature change of a shower or the like from a water heater provided on the demand side. In this water supply device, the pump is stopped during a time period when water is not used, such as at night. The starting pressure in the pipe where the pump restarts is set to a fixed value or less from the stop pressure when the pump stops, and water is retained from the water in the pressure tank until the pipe pressure on the discharge side of the pump drops to the starting pressure. Supply to the demand side. During the period of water supply from the pressure tank, the pump was stopped, and the frequency of starting the pump was kept low.
[0003]
In addition, when the pump is stopped in a state of a small amount of water in the pipe on the pump discharge side, there is a small water volume pressurization stop method of operating the pump with the maximum pumping capacity to pressurize the water pressure in the pipe immediately before stopping the pump. However, the demand side wants a water supply system with as little pressure fluctuation as possible, and even when the pump is not using water, the pump starts after using water if the pressure in the piping is high. Since the pressure of water is in a high pressure state until a certain period, there is a certain limit in improving the usability on the demand side.
[0004]
On the other hand, in order to satisfy the feeling of use on the demand side, the difference between the starting pressure and the stopping pressure of the pump should be as small as possible. However, if the pressure difference is too small, the pump is restarted immediately after the pump is stopped due to a reading error of the pressure detection circuit for detecting the pressure in the pump pipe, and the frequency of starting the pump is increased. Therefore, it is necessary to provide a pressure difference between the pump stop pressure and the start pressure that is at least larger than a reading error of the detection circuit.
[0005]
[Problems to be solved by the invention]
However, in the above-described prior art, the inside of the demand-side pipe is always pressurized at the maximum pumping capacity by the small water pressure pressurization stop method, and thus it is difficult to supply water at an appropriate water pressure. Further, in a water supply mechanism in which there is no difference between the starting pressure and the stopping pressure of the pump, the frequency of starting the pump increases. Therefore, there has been a demand for a water supply apparatus that automatically sets the start pressure of the pump to be lower than the stop pressure.
[0006]
The present invention has been made in view of the above-described circumstances, and aims to provide a variable-speed water supply device that reduces the frequency of water pumping on the demand side as much as possible, reduces the frequency of starting pumps, and brings out an energy-saving effect. Things.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a variable speed water supply apparatus according to the first aspect of the present invention includes, for example, a pump 12, a discharge pipe 14 provided on a discharge side of the pump 12, and a discharge pipe as shown in FIG. 14, a check valve 18 arranged to maintain the pressure in the discharge pipe 14 when the pump 12 is stopped, and a pressure detecting means 20 for detecting the pressure in the discharge pipe 14. A water supply for variably controlling the speed of the motor 22 by using the pressure on the discharge side of the pump 12 as a target pressure of a predetermined estimated terminal pressure, the motor having a motor 22 for driving the pump 12 and a control means 24 for controlling the speed of the motor 22. The apparatus comprises an underwater amount detection means 26 for detecting that the amount of water in the discharge pipe 14 has reached a predetermined underwater amount, and an upper limit pressure PA and a lower limit pressure PB as parameters for sequentially calculating the estimated end pressure. A pressure setting means 28 arbitrarily set from the section, a pressure calculating means 32 for calculating the stop pressure of the pump 12 based on the upper limit pressure PA and the lower limit pressure PB, and calculating a starting pressure of the pump based on the stop pressure. The control means 24 receives the detection signal from the underwater amount detection means 26 when the underwater amount has been reached, and temporarily replaces the discharge pressure of the pump from the target pressure to the stop pressure for a predetermined time. Later, the motor 22 is configured to be stopped.
[0008]
Here, the estimated terminal pressure is, for example, a pressure capable of supplying water to a water supply terminal such as a water heater or a water tap installed at the highest position used on the demand side, and is the highest position from the water supply device. In consideration of the height to the water supply terminal, the faucet loss, and the pipe resistance, for example, it is desirable to use the pressure obtained by adding the pipe loss to the height of the water supply terminal at the highest position. Further, the predetermined time until the motor 22 is stopped may be set to several tens of seconds until the discharge pressure of the pump 12 reaches the stop pressure.
[0009]
With this configuration, the stop pressure of the pump 12 is calculated based on the upper limit pressure PA and the lower limit pressure PB simply by arbitrarily setting the upper limit pressure PA and the lower limit pressure PB by the pressure setting means 28 from the outside. The starting pressure of the pump can be calculated based on the stop pressure, and the target pressure, which is the estimated terminal pressure, is sequentially calculated using the upper limit pressure PA and the lower limit pressure PB as parameters, so that the water pressure required by the demand side is secured. Since the relative relationship between the stop pressure and the start pressure is always maintained, the stop and start of the pump can be repeated at an appropriate frequency. In addition, the motor 22 is stopped after a predetermined period of time after the discharge pressure of the pump is temporarily replaced from the target pressure to the stop pressure in response to the detection of the underwater amount, so that the pressure fluctuation on the demand side is suppressed, and the variable speed is controlled. Energy saving of the water supply device can be achieved.
[0010]
In order to achieve the above object, in the variable speed water supply apparatus according to the first aspect of the present invention, the pump is started when the discharge pressure of the pump reaches the starting pressure.
[0011]
With this configuration, since the starting pressure is calculated based on the upper limit pressure PA and the lower limit pressure PB, the pump 12 is always started at a stage where the pressure has been reduced to an appropriate pressure.
[0012]
In order to achieve the above object, a variable speed water supply device according to the invention according to claim 3 includes, for example, a pump 12 and a discharge provided on the discharge side of the pump 12 as shown in FIGS. 1, 3 and 4. A pipe 14, a pressure tank 16 provided in the discharge pipe 14, a check valve 18 arranged to maintain the pressure in the discharge pipe when the pump 12 is stopped, and a pressure detecting means for detecting the pressure in the discharge pipe 20; a motor 22 for driving the pump 12; and control means 24 for controlling the speed of the motor 22. The speed of the motor 22 is variably controlled using the pressure on the discharge side of the pump 12 as a target pressure of a predetermined estimated terminal pressure. A water supply device, which detects that the amount of water in the discharge pipe 14 has reached a predetermined underwater amount, and an upper limit pressure PA and a lower limit pressure P as parameters for sequentially calculating the estimated terminal pressure. And a pressure setting unit 28 that arbitrarily sets the pressure difference from the upper limit pressure PA and the lower limit pressure PB when the control unit 24 receives the underwater amount detection signal from the underwater amount detection unit 26. When the pressure difference is larger than the differential pressure DP, the motor 22 is operated for a predetermined time until the discharge pressure of the pump is equal to the sum of the lower limit pressure PB and the differential pressure DP. After a predetermined time, the motor 22 is stopped, and if the pressure difference is smaller than the differential pressure DP, the motor 22 is operated for a predetermined time until the discharge pressure of the pump at the upper limit pressure PA, and the motor is stopped after the predetermined time. Constitute.
[0013]
Here, the upper limit pressure PA corresponds to, for example, an allowable upper limit pressure of the estimated terminal pressure, and the lower limit pressure PB corresponds to an allowable lower limit pressure of the estimated terminal pressure. With the pressure between the upper limit pressure PA and the lower limit pressure PB, water is supplied to a water supply terminal such as a water heater or a water tap installed at the highest position used on the demand side. As the lower limit pressure, it is desirable to use a pressure in consideration of the height from the water supply device to the water supply terminal at the highest position, faucet loss, and pipe resistance.
[0014]
With this configuration, when the control means 24 receives the underwater amount detection signal from the underwater amount detection means 26, the variable speed water supply device calculates the value obtained by adding the lower limit pressure PB and the differential pressure DP or the upper limit pressure PA. Since the discharge pressure of one of the pumps is limited, the estimated end pressure is controlled to be constant while suppressing the fluctuation of the feedwater pressure.
[0015]
To achieve the above object, the variable speed water supply device according to claim 3 according to the invention according to claim 4 is configured such that the pressure in the discharge pipe 14 is different from the discharge pressure of the pump when the motor 22 is stopped. The pump 12 is configured to start when the pressure reaches the pressure obtained by subtracting the pressure DP.
[0016]
With this configuration, the variable-speed water supply device can start the pump at an appropriate starting pressure because the starting pressure is calculated based on the discharge pressure of the pump at the time of performing the underwater stop.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 8 show an example of an embodiment of the present invention. In the drawings, portions denoted by the same or similar reference numerals as those in the drawings represent the same or corresponding components, and redundant description will be omitted.
[0018]
FIG. 1 is a schematic system diagram of a variable speed water supply device 10 according to a first embodiment of the present invention. The variable-speed water supply device 10 includes a water pipe 35 for supplying water from a water pipe or a water receiving tank, a pump 12 connected to the water pipe 35, a discharge pipe 14 provided on a discharge side of the pump 12, and a pump 12. It includes a motor 22 to be driven and control means 24 for controlling the motor 22 via an inverter 36.
[0019]
In the discharge pipe 14, a flow switch 26, a check valve 18, a pressure sensor 20, and a pressure tank 16, in order from a discharge side of the pump 12, as a means for detecting an underwater amount, are arranged in the direction of a demand side water supply terminal 38. It is arranged.
[0020]
The control means 24 is connected to the pressure sensor 20 and the flow switch 26, and receives the water pressure and the water amount in the discharge pipe 14 by an electric signal. The control unit 24 is connected to the pressure setting unit 28 and is configured to input numerical values of the upper limit pressure PA and the lower limit pressure PB from the input panel 30. The input panel 30 is composed of numerical display means such as a liquid crystal screen and numeric keys or numeric keys for increasing or decreasing the numerical value. The upper limit pressure PA and the lower limit pressure PB are input by a touch input method or a press button method on the liquid crystal screen. Further, the control unit 24 receives the number of rotations of the motor 22 or the pump 12 via an output line 23 from a rotary encoder provided in the motor 22.
[0021]
The control means 24 stores the numerical values of the upper limit pressure PA and the lower limit pressure PB input from the pressure setting means 28 in an internal memory 34 via an internal central processing unit CPU 32, and performs gate control of the motor 22 which has been internally processed. By transmitting a signal to the inverter 36, the gate transistor inside the inverter 36 is driven. The inverter 36 drives the pump 12 by applying a speed control signal to the electrically connected motor 22. For example, using a pulse width modulation method PWM or a pulse amplitude modulation method PAM, the AC voltage is steplessly controlled, and the pump 12 is rotated efficiently and at high speed.
[0022]
Next, the operation of the variable speed water supply device 10 will be described. Water discharged from a water pipe or a water receiving tank by the pump 12 driven by the motor 22 through the water pipe 35 is supplied to the demand side water supply terminal 38 through the discharge pipe 14 at a predetermined pressure. The water supply terminal 38 is a water heater or a water tap provided at each of the branched discharge pipes 14, and water pumped by the pump 12 is provided at the highest position of a middle-rise house, a high-rise house, a commercial building, or the like. It is pressurized to a pressure sufficient to supply water.
[0023]
A flow switch 26 and a check valve 18 for maintaining the pressure in the discharge pipe when the pump 12 is stopped are inserted into the discharge pipe 14. The discharge pipe 14 is connected to the pressure tank 16 via the branch pipe 17 from the discharge pipe 14. The water inside is stored.
[0024]
A pressure sensor 20 disposed downstream of the check valve 18 detects the pressure in the pressure tank 16 from the discharge pipe 14 via the branch pipe 21 or the pressure on the discharge side of the check valve 18, and outputs an electric signal. Is transmitted to the control means 24. The flow switch 26 operates when the discharge amount discharged from the pump 12 to the discharge pipe 14 reaches the underwater amount or less, and transmits a underwater amount detection signal to the control means 24.
[0025]
Further, water supply is started by an operation switch of the variable speed water supply device 10, but it is also possible to configure such that the underwater amount stop processing is canceled for a certain time after the start of the pump 12 start. That is, if there is a condition that water does not flow for a while after the start of the pump 12 due to various conditions of the water supply equipment, it is possible to suppress a problem that the underwater amount stop process is performed.
[0026]
Further, in order to prevent the pump discharge pressure from constantly dropping below a certain value during operation of the pump, if the pump discharge pressure is below a certain value, the control means 24 will be too low even if the flow switch 26 detects an underwater amount. It may be programmed not to start the water amount stop processing. By programming in this way, the pump discharge pressure is prioritized, and the frequency of the underflow stop process is reduced.
[0027]
When the pressure in the discharge pipe 14 exceeds the lower limit pressure PB due to the use of water on the demand side, the pump 12 driven by the motor 22 operates continuously. When the water use on the demand side increases and the water pressure in the discharge pipe 14 further decreases, the pressure sensor 20 detects a decrease in the supply water pressure. The detected pressure signal is sent to the control means 24, and the control means 24 sequentially calculates the target pressure, which is the estimated terminal pressure on the demand side, using the upper limit pressure PA and the lower limit pressure PB as parameters, and temporarily stores it in the internal memory 34.
[0028]
The upper limit pressure PA and the lower limit pressure PB are determined in consideration of conditions when the pump 12 is installed, that is, a height of a building for supplying water, a length of a pipe to a water tap, a pressure in the discharge pipe 14 to be guaranteed, and the like. Thus, the pressure can be changed by an external pressure setting means 28.
[0029]
The control means 24 controls the inverter 36 to apply an AC voltage to the motor 22 to increase the speed. As the motor 22 rotates at an increased speed, the discharge amount of the pump 12 increases. The water pressure in the discharge pipe 14 increases and is sequentially detected by the pressure sensor 20, and a pressure detection signal is sent to the control unit 24. The control means 24 sequentially compares the pressure detection signal with the upper limit pressure PA and the lower limit pressure PB so as to control the water pressure in the discharge pipe 14 within the range of the upper limit pressure PA and the lower limit pressure PB, and sequentially calculates the estimated end pressure. The calculation is performed, and the rotation speed of the motor 22 is controlled via the inverter 36.
[0030]
FIG. 2 is an operation characteristic diagram of the variable speed water supply device 10 according to the first embodiment of the present invention. The horizontal axis indicates the water amount Q and the vertical axis indicates the pressure H, and the QH performance of the pump 12 is shown. A virtual contact point 50 on the pump performance curve indicates the water amount Q1 and the pressure H when the pump 12 is operating at the maximum output with the rotation speed increasing with the increase in the water usage, and the pressure at this time is the lower limit. The pressure PB is calculated. In the present embodiment, the operation is performed in a state where the amount of water used on the demand side decreases and the pressure in the discharge pipe 14 increases to the contact point 52 on the pump performance curve. The pressure sensor 20 detects an increase in the feedwater pressure and transmits a detection signal to the control means 24. For example, the pressure at this time is the upper limit pressure PA, and the water amount is Q2.
[0031]
The control means 24 transmits a control signal to the inverter 36 to decelerate the motor 22 based on the detection signal from the pressure sensor 20, and supplies an AC output from the inverter 36 to decelerate the motor 22. The motor 22 decelerates in response to a decrease in the frequency or voltage of the applied AC output, and decelerates the driven pump 12 to reduce the amount of water discharged.
[0032]
When the pump 12 decelerates, for example, as shown by a pipe resistance characteristic curve from the contact point 52 to the contact point 56 via the contact point 54 on the pump performance curve, the upper limit pressure PA, the lower limit pressure PB, and the real time The motor 22 is controlled while comparing the pressure in the discharge pipe 14 with the estimated end pressure. The pressure at the time of the illustrated water amount Qx is calculated as Px. Thus, the estimated terminal pressure is typically on a pipe resistance characteristic curve, and the upper limit pressure PA and the lower limit pressure PB corresponding to the flow rate at this time. Varies with range.
[0033]
When the demand-side water usage further decreases, the pump 12 supplies water below the water amount Qmin corresponding to the contact point 56 on the pump performance curve. In this case, the rotation of the motor 22 and the pump 12 is further reduced, and the efficiency becomes extremely low. Further, if the operation is continued as it is, a problem such as an increase in the temperature in the pump occurs. The state is set so that the flow switch 26 detects the state.
[0034]
It is desirable that the control means 24 starts the underwater amount stop process after confirming that the underwater amount has continued for a certain time and the pump discharge pressure has not decreased for a certain time at the stage when the flow switch 26 operates.
[0035]
The time for confirming that the underwater quantity state is reliable is sequentially changed, for example, according to the operation state of the pump 12 immediately before. In order to reduce the frequency of starting the pump 12, the time for confirming the underwater volume state is as follows. First, the time when the pump 12 is operating immediately before is long, and second, the time when the pump 12 is stopped last time is In consideration of various conditions such as a long time, and thirdly, the frequency of opening and closing of the flow switch 26 is small, it is possible to shorten the check time of the underwater amount stop processing.
[0036]
The length of the confirmation time of the underwater amount stop processing can be achieved by performing a fuzzy inference on the factor that determines the fixed time. This fixed time may be set to an arbitrary value between zero seconds and 160 seconds, for example. Providing the confirmation time for the underwater amount stop process in this manner can reduce the frequency of starting the pump 12 and also achieve energy saving of the variable speed water supply device 10.
[0037]
The control means 24 receives a detection signal indicating that the amount of water has reached an undersized amount from the flow switch 26, and temporarily changes the discharge pressure of the pump 12 from the estimated end pressure as the target pressure to the stop pressure. The target pressure is data temporarily stored in the internal memory 34 of the control means 24, and the stop pressure is data calculated based on the input upper limit pressure PA and lower limit pressure PB. Therefore, the control means 24 forcibly replaces the estimated end pressure data, which is the target pressure calculated sequentially, with the stop pressure data to control the rotational speed of the motor 22 to increase, and the water pressure in the discharge pipe 14 is indicated by an arrow 55. Speed increase control is performed so as to be on the pump characteristic curve shown. Subsequently, the speed of the motor 22 is increased to drive the pump 12, and the speed of the pump is controlled so as to be on the pump characteristic curve indicated by the arrow 57. Thus, the discharge pressure of the pump 12 is configured to reach the stop pressure.
[0038]
The motor 22 continuously drives the pump 12 so as to approach the stop pressure by using the above-described detection signal of the underwater amount as a trigger, and monitors the clock of the timer 52 in the control means 24 in parallel to detect the time-up. Be programmed. Subsequently, even when the water usage on the demand side further decreases or reaches zero, the pump 12 is rotating until the control means 24 detects the time up. The control means 24 stops the motor 22 when the timer expires. For example, for a predetermined period of time to be timed up based on the experimental results of the inventor of the present application, the water level in the pressure tank 16 is raised by the water flowing into the pressure tank 16 from the pump 12 through the discharge pipe 14 after the detection of the underwater volume, and If the water pressure in the pipe 14, in other words, the water pressure in the pressure tank 16 is arbitrarily selected from zero seconds to 160 seconds, which is a time sufficient for raising the pressure to the upper limit pressure PA which is the stop pressure or more. Good.
[0039]
As described above, when pressurizing with the pump at the time of stoppage of the underwater amount, the control means 24 calculates the stop pressure as the pressurized value by the underwater amount stop processing and temporarily stores the stop pressure in the internal memory 34, so that the pump 12 Start operation. The variable-speed water supply device 10 configured as described above can perform the under-water-amount stop processing even if the stop pressure is not stored in the internal memory 34 in advance.
[0040]
The control means 24 includes a central processing unit CPU 32 as a calculation means, and calculates the stop pressure of the pump based on the upper limit pressure PA and the lower limit pressure PB input to the internal memory 34. For example, as described above, the stop pressure is calculated so as to calculate a value of the upper limit pressure PA or a pressure higher than the upper limit pressure PA. Further, it is programmed to calculate the starting pressure of the pump based on the value of the stop pressure. For example, it is desired that the starting pressure is programmed to be calculated to a pressure equal to the lower limit pressure PB or a pressure slightly lower than the lower limit pressure PB.
[0041]
Further, the variable speed water supply device 10 sets the upper limit pressure PA at a stage where the water supply terminal 38 is installed at the site after shipment from the factory, for example, to a height of 14 meters when the highest position of the water supply terminal 38 is the fifth floor of the building. The water supply pressure is input, and the lower limit pressure PB at which water can be supplied at a height of 12 meters, which is about 15% lower, is input. The unit of this input may be the height of the building in meters or the water pressure may be directly input. However, in general, since the height of the building is higher than the highest position of the water supply terminal 38, it is convenient. It is desirable to input the height value of the building corresponding to the upper limit pressure PA in units of meters in order to prevent erroneous input. The reason for inputting the value of the lower limit pressure PB about 15% lower than the upper limit pressure PA is that the pipe resistance is estimated to be about 15%.
[0042]
As described above, the upper limit pressure PA and the lower limit pressure PB are configured to be manually settable from outside. However, as the set values, two parameters of the upper limit pressure PA and the decrease percentage (D%) are input, and the upper limit pressure PA and the lower limit pressure DB are set. By configuring to input the pressure PA and the differential pressure DP, it is possible to prevent the upper limit pressure PA from becoming smaller than the lower limit pressure PB due to an erroneous operation of manual setting.
[0043]
For example, the lower limit pressure PB can be obtained by calculating PB = PA− (PA × D%) by the control unit 24. As another method, the control unit 24 calculates PB = PA−DP. do it. When the upper limit pressure PA is set to the same value as the lower limit pressure PB, the discharge pressure of the pump 12 can be controlled to be constant. In this case, since the pump stop pressure is PA (= PB) and the start pressure is PA-DP, excessive pressurization by the pump 12 is not performed.
[0044]
FIG. 3 is a diagram showing the relationship between the stop pressure and the start pressure of the pump 12 used in the variable speed water supply device 10 according to the second embodiment of the present invention. The variable speed water supply device 10 uses the same device as that of the above-described embodiment, and thus redundant description will be omitted.
[0045]
The horizontal axis shows the rotation control state of the pump over time, and the vertical axis shows the relationship between the stop pressure and the start pressure taking the pressure H. Data of the differential pressure DP is stored in the internal memory 34 of the control means 24 in advance. For example, in the variable speed water supply device 10 used for a building having about five stories, the differential pressure DP is set to 2.5 meters.
[0046]
The variable speed water supply device 10 arbitrarily sets an upper limit pressure PA and a lower limit pressure PB as parameters for sequentially calculating the estimated terminal pressure from outside, and the control unit 24 receives an underwater amount detection signal from the underwater amount detection unit 26. At this time, the pressure difference between the upper limit pressure PA and the lower limit pressure PB is compared with a preset differential pressure DP, and if the pressure difference is smaller than the differential pressure DP, the target pressure is replaced with the stop pressure and the upper limit pressure PA The motor 22 is operated for a predetermined time up to the discharge pressure of the pump, and the motor is stopped after a predetermined time has elapsed.
[0047]
The illustrated contact 56 indicates the water pressure in the discharge pipe 14 at the time when the underwater amount is detected. The control means 24 has started time-up of the timer, and rotates the motor 22 in parallel to increase the discharge pressure of the pump 12 toward the upper limit pressure PA as the stop pressure. In the present embodiment, the difference between upper limit pressure PA and lower limit pressure PB is set to 2 meters, and differential pressure DP is set to 2.5 meters.
[0048]
The illustrated contact 58 is in a state where the pump 12 is continuously operating, and the pressure in the discharge pipe 14 has increased to the stop pressure or higher. Thereafter, the motor 22 is stopped when the control unit 24 detects that the time is up, and the pressure in the discharge pipe 14 is maintained at or above the upper limit pressure PA by the pressure tank 16.
[0049]
Subsequently, the pressure in the discharge pipe 14 is maintained at or above the upper limit pressure PA, but the water pressure in the discharge pipe 14 gradually decreases due to water use on the demand side or water leakage in the discharge pipe 14 system. The illustrated contact 60 indicates the pressure obtained by subtracting the differential pressure DP from the stop pressure (upper limit pressure PA), which is the discharge pressure of the pump 12 when the motor 22 stops the water pressure in the discharge pipe 14.
[0050]
For example, when the pressure in the discharge pipe 14 has decreased to a pressure equivalent to 2.5 meters below the upper limit pressure PA, the pressure sensor 20 detects the starting pressure and sends a signal to the control means 24, and the control means 24 By driving the pump 12 by rotating the motor 22 via 36, the pressure in the discharge pipe 14 can be increased. Moreover, since the starting pressure is set to be lower than the lower limit pressure PB by 0.5 meter, the period between the stop and start of the pump 12 can be made longer.
[0051]
Here, the starting pressure uses the pressure obtained by subtracting the differential pressure DP from the stop pressure PA at the time when the motor 12 is stopped after the contact point 58, but simplifies the configuration of the variable speed water supply device 10. This is effective in the sense that the starting pressure does not need to be stored in the internal memory 34 in advance, and if a starting pressure is set from the outside, a malfunction due to a numerical input error can be prevented beforehand.
[0052]
FIG. 4 is a diagram showing the relationship between the stop pressure and the start pressure of the pump 12 used in the variable speed water supply device 10 according to the second embodiment of the present invention. The case where the difference between the illustrated upper limit pressure PA and the lower limit pressure PB is larger than the differential pressure DP will be described. That is, when the pressure difference between the upper limit pressure PA and the lower limit pressure PB is larger than the differential pressure DP, the variable speed water supply device 10 controls the motor 22 to reach the discharge pressure of the pump obtained by adding the lower limit pressure PB and the differential pressure DP. The motor 22 is operated for a predetermined time, and after a predetermined time, the motor 22 is stopped.
[0053]
The illustrated contact 56 indicates the water pressure in the discharge pipe 14 at the time when the underwater amount is detected. The control means 24 starts the time-up of the timer, and rotates the motor 22 in parallel to set the discharge pressure of the pump 12 to a pressure obtained by adding the lower limit pressure PB as the stop pressure and the differential pressure DP to the pressure. It is rising to head. In the present embodiment, the difference between upper limit pressure PA and lower limit pressure PB is set to 3 meters, and differential pressure DP is set to 2.5 meters.
[0054]
The illustrated contact 62 is in a state where the pump 12 is continuously operated, and the pressure in the discharge pipe 14 has been increased to the stop pressure or higher. Thereafter, the motor 22 is stopped when the control unit 24 detects that the time is up, and the pressure in the discharge pipe 14 is maintained at or above the stop pressure by the pressure tank 16.
[0055]
Subsequently, the pressure in the discharge pipe 14 is maintained at or above the stop pressure, but the water pressure in the discharge pipe 14 gradually decreases due to water usage on the demand side or water leakage in the discharge pipe 14 system. The illustrated contact point 64 indicates a pressure (lower limit pressure PB) obtained by subtracting the differential pressure DP from the stop pressure which is the discharge pressure of the pump 12 when the water pressure in the discharge pipe 14 stops the motor 22.
[0056]
For example, when the pressure in the discharge pipe 14 has decreased to a pressure equivalent to 2.5 meters below the stop pressure, the pressure sensor 20 detects the starting pressure and sends a signal to the control means 24, and the control means 24 The pressure in the discharge pipe 14 can be increased by driving the pump 12 by rotating the motor 22 via the. In addition, since the stop pressure is set to be 0.5 m lower than the upper limit pressure PA, even if the pressure in the discharge pipe 14 is increased by the pump 12 until the control unit 24 times out, the upper limit pressure PA is excessively exceeded. Since there is no pressure fluctuation, the pressure fluctuation of the water supply terminal 38 can be suppressed.
[0057]
As described above, according to the present embodiment, the stop pressure of the pump 12 is determined based on the parameters of the upper limit pressure PA, the lower limit pressure PB, and the differential pressure DP. The upper limit of the pressurized value can be automatically restricted, and the fluctuation of the pressure in the discharge pipe 14 can be suppressed.
[0058]
The relationship between the stop pressure and the start pressure of the pump 12 used in the variable speed water supply device 10 according to the third embodiment of the present invention will be described with reference to FIG. The variable speed water supply device 10 inputs the same value from the pressure setting means 28 to the upper limit pressure PA and the lower limit pressure PB.
[0059]
When the power is turned on after the same upper limit pressure PA and lower limit pressure PB are set, the variable speed water supply device 10 shifts to the operation mode, and the difference between the upper limit pressure PA and the lower limit pressure PB is automatically set to the differential pressure. The control means 24 determines that the parameter is smaller than DP. The control means 24 controls the motor 22 to increase the speed of the pump 12 while calculating the estimated terminal pressure as a function of the upper limit pressure PA and the lower limit pressure PB.
[0060]
Immediately after the variable speed water supply device 10 is installed at a site such as a building, the pressure in the discharge pipe 14 is zero. Therefore, the discharge pressure of the pump 12 performs water supply from zero to the upper limit pressure PA. The illustrated contact 66 is in a state where the pump 12 is operated for a predetermined time after detecting the underwater amount, and then the pump 12 is stopped, and the pressure in the discharge pipe 14 is maintained by the pressure tank 16 at or above the upper limit pressure PA. Indicates a state in which
[0061]
Next, water is used from the water supply terminal 38 on the demand side, or the pressure in the discharge pipe 14 gradually decreases due to water leakage. The illustrated contact 68 indicates the pressure obtained by subtracting the differential pressure DP from the stop pressure (PA or PB) when the water pressure in the discharge pipe 14 stops the motor 22.
[0062]
For example, when the pressure in the discharge pipe 14 has decreased to a pressure equivalent to 2.5 meters below the upper limit pressure PA, the pressure sensor 20 detects the starting pressure and sends a signal to the control means 24, and the control means 24 By driving the pump 12 by rotating the motor 22 via 36, the pressure in the discharge pipe 14 can be increased. Moreover, since the starting pressure is calculated and output 2.5 meters lower than the upper limit pressure PA, the timing of stopping and starting the pump 12 can be made longer.
[0063]
The starting pressure uses a pressure obtained by subtracting the differential pressure DP from the stop pressure PA or PB at the time when the motor is stopped at the contact 66, but in a sense of simplifying the configuration of the variable speed water supply device 10. It is effective, and it is more effective to calculate the starting pressure by the control means 24 than to temporarily detect the pressure in the discharge pipe 14 by the pressure sensor 20 and subtract the differential pressure DP from the pressure when the pump is stopped. Can be reduced.
[0064]
Furthermore, in the variable speed water supply device 10 for daily operation, the motor 22 is rotated at a variable speed while the estimated terminal pressure is calculated using the upper limit pressure PA and the lower limit pressure PB of the same value as parameters, and the pump 12 is driven. Is supplied to the water supply terminal 38 of FIG.
[0065]
FIG. 6 is a block diagram of the control means 24 used in the variable speed water supply device 10 according to the embodiment of the present invention. The control means 24 includes a central processing unit CPU 32, an internal memory 34 connected to the CPU 32 via a bus 48, a timer 52, and an interface I / O 46.
[0066]
The internal memory 34 includes an electrically rewritable programmable read only memory EEPROM 40, a random access memory RAM 42, and a read only memory ROM 44, each of which is connected to the CPU 32.
[0067]
The EEPROM 40 stores data of the differential pressure DP, the upper limit pressure PA, and the lower limit pressure PB. These data have initial values written at the factory shipment stage, but can be manually input and rewritten from the pressure setting means 28 via the CPU 32 when installed at a demand destination. Since the EEPROM holds the data of the upper limit pressure PA, the lower limit pressure PB, and the differential pressure DP even when the variable speed water supply device 10 is not energized, the EEPROM stores or sets the target pressure data in the control means 24. It is not necessary, and it is possible to maintain an efficient operation state by appropriately re-inputting the parameters of the upper limit pressure PA or the lower limit pressure PB with respect to the performance deterioration due to the temporal change of the motor 22 or the pump 12, thereby achieving energy saving. .
[0068]
The RAM 42 temporarily stores the result of the CPU 32 calculating the estimated terminal pressure, which is the target pressure, using the upper limit pressure PA and the lower limit pressure PB as parameters. The RAM 42 erases data when the variable-speed water supply device 10 is not energized for a predetermined period of time. However, since the unit price is relatively low, the cost of the variable-speed water supply device 10 can be reduced.
[0069]
The ROM 44 is a read-only memory such as a mask ROM or an EPROM, and stores a program for a variable speed water supply method. Further, a calculation table for calculating the estimated terminal pressure can be stored. For example, the upper limit pressure PA value is input to the upper address line of the operation table, the lower limit pressure PB value is input to the lower address line, and the estimated terminal pressure is output to the data output line. When such an operation table is used, the operation speed is higher than when the register of the CPU 32 is used, and fine-grained pump control can be performed.
[0070]
The interface I / O 46 receives an electric signal from the flow switch 26, the pressure sensor 20, the pressure setting means 28, and the output line 23 of the rotary encoder, and performs a buffer function to be passed to the CPU 32 and conversion of a signal level. Further, it transmits a control signal output from the CPU 32 to the inverter 36.
[0071]
The timer 52 has a calendar function and outputs real-time clock data to the CPU 32. The timer 52 updates the nonvolatile calendar information by receiving power supply from a button battery or the like as a backup power supply (not shown). In addition, since the variable-speed water supply device 10 is always energized during normal operation, a backup power supply for the timer 52 can be secured with a DC voltage obtained by transforming a commercial power supply.
[0072]
7 and 8 are control flowcharts of the variable speed water supply device 10 according to the embodiment of the present invention. With reference to FIG. 7, a description will be given of a state in which the variable speed water supply device 10 performs a pressurizing operation in a range from the contact point 52 to the contact point 56 of the pump performance curve.
[0073]
Step 70 shows a process at a stage when the flow switch 26 detects the underwater amount. The control means 24 determines in step 71 whether the difference between the upper limit pressure PA and the lower limit pressure PB is smaller than the differential pressure DP. If the determination result is negative (large), the process branches to step 72, in which the stop pressure obtained by adding the differential pressure DP to the lower limit pressure PB is replaced with the estimated terminal pressure as the target pressure, and the pump 12 is operated for a predetermined time. Then, the pressure in the discharge pipe 14 is increased to the stop pressure or more, and the process proceeds to step 73 to perform the stop processing of the pump 12. The predetermined time is set to an arbitrary value from, for example, 20 seconds to 160 seconds.
[0074]
On the other hand, if the determination result in step 71 is positive (small), the flow branches to step 74, where the value of the upper limit pressure PA is calculated and output as the stop pressure and replaced with the estimated end pressure as the target pressure, and then the pump By operating the pump 12, the pressure in the discharge pipe 14 is increased to the stop pressure or higher, and the routine proceeds to step 73, where the pump 12 is stopped. The value of the predetermined time is set between 20 seconds and 160 seconds as described above.
[0075]
The restart process of the pump 12 of the variable speed water supply device 10 will be described with reference to FIG. The control means 24 periodically monitors the output signal of the pressure sensor 20. Step 75 is a state in which the pump 12 is stopped and the pressure in the discharge pipe 14 is maintained at the pressure of the pressure tank 16 or water is supplied to the demand side.
[0076]
The control means 24 determines in step 76 whether the difference between the upper limit pressure PA and the lower limit pressure PB is smaller than the differential pressure DP. If the determination is negative (large), the flow branches to step 77, and it is determined whether the pressure PF in the discharge pipe 14 is higher than the lower limit pressure PB. If the determination result is positive (large), the process branches to step 78 to stop restarting the pump 12 and acquire a signal from the pressure sensor 20 at the next monitoring timing. If the determination result in step 77 is negative (small), the process branches to step 80 to restart the pump 12.
[0077]
On the other hand, if the result of the determination in step 76 is positive (small), the flow branches to step 79, in which it is determined whether the pressure PF in the discharge pipe 14 is greater than the pressure obtained by subtracting the differential pressure DP from the upper limit pressure PA. If the determination result is positive (large), the process branches to step 78 to stop restarting the pump 12 and acquire a signal from the pressure sensor 20 at the next monitoring timing. If the result of the determination in step 79 is negative (small), the process branches to step 80 to restart the pump 12.
[0078]
Thus, according to the embodiment of the present invention, even if the stop pressure and the start pressure of the pump 12 are not stored in the EEPROM 40 in advance, the internal calculation processing is automatically performed only by inputting a predetermined parameter such as the upper limit pressure PA. Thus, the stop pressure and the start pressure of the pump 12 can be determined.
[0079]
It should be noted that the variable speed water supply device of the present invention is not limited to the illustrated example described above, and it is needless to say that various changes can be made without departing from the gist of the present invention.
[0080]
【The invention's effect】
As described above, according to the variable speed water supply device of the present invention, a variable speed water supply device that reduces the frequency of starting and stopping the pump and suppresses the energy saving while suppressing the pressure fluctuation of the water on the demand side is provided. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic system diagram of a variable speed water supply device according to a first embodiment of the present invention.
FIG. 2 is an operation characteristic diagram of the variable speed water supply device according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a relationship between a stop pressure and a start pressure of a pump used in a second embodiment of the present invention.
FIG. 4 is a diagram showing a relationship between a stop pressure and a start pressure of a pump used in a second embodiment of the present invention.
FIG. 5 is a diagram showing a relationship between a stop pressure and a start pressure of a pump used in a third embodiment of the present invention.
FIG. 6 is a schematic block diagram of control means used in the embodiment of the present invention.
FIG. 7 is a processing flowchart of the variable speed water supply device according to the embodiment of the present invention.
FIG. 8 is a processing flowchart of the variable speed water supply device according to the embodiment of the present invention.
[Explanation of symbols]
10 variable speed water supply device
12 pumps
14 discharge tubes
16 pressure tank
18 check valve
20 pressure sensor
22 motors
24 control means
26 flow switch
28 pressure setting means
30 input panel
32 central processing unit
34 internal memory
35 water piping
36 inverters
38 water supply terminal
52 timer

Claims (4)

A pump, a discharge pipe provided on the discharge side of the pump, a pressure tank provided on the discharge pipe, and a check valve arranged to maintain the pressure in the discharge pipe while the pump is stopped, Pressure detection means for detecting the pressure in the discharge pipe, a motor for driving the pump, and control means for controlling the speed of the motor, wherein the pressure on the discharge side of the pump is a target pressure of a predetermined estimated terminal pressure. A water supply device for variably controlling the speed of the motor;
An underwater amount detection means for detecting that the amount of water in the discharge pipe has reached a predetermined underwater amount;
Pressure setting means for externally arbitrarily setting an upper limit pressure PA and a lower limit pressure PB as parameters for sequentially calculating the estimated terminal pressure;
Pressure calculating means for calculating a stop pressure of the pump based on the upper limit pressure PA and the lower limit pressure PB, and calculating a starting pressure of the pump based on the stop pressure;
The control unit receives a detection signal from the underwater amount detection unit at a stage when the underwater amount has been reached, and temporarily replaces the discharge pressure of the pump from the target pressure to the stop pressure, after a predetermined time. Stopping the motor;
Variable speed water supply. The variable speed water supply device according to claim 1, wherein the pump is started when the discharge pressure of the pump reaches the starting pressure. A pump, a discharge pipe provided on the discharge side of the pump, a pressure tank provided on the discharge pipe, and a check valve arranged to maintain the pressure in the discharge pipe while the pump is stopped, A pressure detecting means for detecting a pressure in the discharge pipe, a motor for driving the pump, and a control means for controlling a speed of the motor, wherein the pressure on the discharge side of the pump is a predetermined estimated terminal pressure and the motor A water supply device for variably controlling the speed of the water;
An underwater amount detection means for detecting that the amount of water in the discharge pipe has reached a predetermined underwater amount;
Pressure setting means for arbitrarily setting externally an upper limit pressure PA and a lower limit pressure PB as parameters for sequentially calculating the estimated terminal pressure;
The control means, when receiving the underwater quantity detection signal from the underwater quantity detection means, compares the pressure difference between the upper limit pressure PA and the lower limit pressure PB with a preset differential pressure DP, and the pressure difference is When the pressure difference is larger than the differential pressure DP, the motor is operated for a predetermined time until the pump discharge pressure reaches a value obtained by adding the lower limit pressure PB and the differential pressure DP, and after a predetermined time, the motor is stopped, and When the difference is smaller than the differential pressure DP, the motor is operated for a predetermined time until the discharge pressure of the pump at the upper limit pressure PA, and after a predetermined time, the motor is stopped;
Variable speed water supply. The variable speed water supply device according to claim 3, wherein the pump is started when the pressure in the discharge pipe reaches a pressure obtained by subtracting the differential pressure DP from a discharge pressure of the pump when the motor is stopped. .

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