JP2006057623A - Water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct-connection type water supply system capable of reducing installation cost and running cost of the system and being suitably used for water supply to in particular relatively low-rise and small buildings. <P>SOLUTION: This water supply system is provided with a suction pipe 5 connected to a distributing pipe 2; a single pressure pump 3 connected to the suction pipe 5; a motor 4 for driving the pressure pump 3; a discharge pipe 6 connected to the discharge side of the pressure pump 3; a bypass pipe 7 bypassing the pressure pump 3 and connected to the suction pipe 5 and discharge pipe 6; a discharge pressure detecting device 12 for detecting discharge pressure of fluid pressurized by the pressure pump 3; and a control device 40 for controlling the pressure pump 3. The control device 40 is provided with a calculating part 61 calculating target pressure for making terminal pressure of a destination of the pressurized fluid approximately constant regardless of a discharge flow rate of the pressure pump 3; and a rotational speed control part 59 for controlling the rotational speed of the motor 4 such that the discharge pressure detected by the discharge pressure detecting device 12 corresponds to the calculated target pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a water supply apparatus that is directly connected to a water main (distribution pipe) and, in particular, supplies water from a water main (distribution pipe) to a terminal customer (terminal water supply equipment) by a single pressurizing pump. The present invention relates to a directly connected water supply device.

  A direct-connection water supply device has been used in the past to pressurize water from a water main (distribution pipe) directly with a pressure pump (booster pump) without going through a water receiving tank, and supply water to a terminal water supply device (customer). Yes. Such conventional directly connected water supply systems are intended for large buildings such as relatively high-rise apartment buildings and buildings where boosting up with large pumps is indispensable. In order to connect directly to water outage, it is essential to have a backup function with multiple pumps. For this reason, the conventional water supply device is provided with a plurality of pumps, and when an abnormality of a specific pump or an inverter for speed control is detected during operation, the operation is performed on another normal pump or inverter. Switching to continue water supply.

  However, in a relatively low-rise and small-scale housing complex of about 2 to 5 floors, in most cases, it is possible to supply water to the end demand destination only by the pressure of the water main (distribution pipe). For such buildings as well, it is often the case that a directly connected water supply apparatus as described above is installed assuming that the water supply pressure on the upper floor is rarely insufficient due to a decrease in the pressure of the water main. However, since it is usually possible to supply water to the end demand by only the pressure of the water main, it is rare that the pump is operated. Therefore, the direct connection type water supply apparatus provided with a plurality of conventional pumps is a heavy burden in terms of cost and installation location.

  Further, in the conventional directly connected water supply device, a suction side pressure sensor for detecting the water main pressure on the suction side of the pump, and a discharge side pressure sensor for detecting the pump discharge pressure on the discharge side of the pump, Is provided. Then, based on the pressure detected by the pressure sensor, the pump rotation speed is changed by the inverter to change the pump performance, and the discharge pressure constant control or the estimated terminal pressure constant control is performed. In this case, in the constant discharge pressure control, the pump discharge pressure is detected by the discharge side pressure sensor, and the pump rotation speed is adjusted by the inverter so that the pump discharge pressure matches the set pressure by comparison with the set pressure. Increase or decrease. Normally, in the constant discharge pressure control, the target pressure is set in anticipation of the pressure loss of the pipe line that occurs at the maximum water volume, so water is supplied at a pressure higher than necessary in an area where the water volume is low. . In actual water supply, the maximum amount of water is rare, and most of it is used in the range of less than that amount, and the power for the estimated loss pressure is wasted.

  On the other hand, in the estimated terminal pressure constant control, the pipe terminal pressure is estimated and the target pressure on the pump discharge side is changed, so that waste of power as in the discharge pressure constant control can be eliminated. A control device that performs constant control of the estimated terminal pressure usually includes a target pressure calculation unit and a PI calculation unit, and calculates a target pressure according to a speed command value (operation speed value at that time) fed back by the target pressure calculation unit. To do. The calculated target pressure is input to the PI calculation unit, and the pressure at that time (discharge pressure detected by the discharge-side pressure sensor) is input to the PI calculation unit, and the pressure at that time is compared with the target pressure. The pump speed command value is output to the inverter to control the speed so that the pressure matches the target pressure. The output pump speed command value is input again to the target pressure calculation unit. By repeating such an operation every predetermined time, it is possible to control to an optimum value in consideration of the pressure loss of the pump discharge pressure when the specific water amount is reached.

  In the direct water supply method, the pump suction pressure changes with the pressure fluctuation of the water main (distribution pipe). When the pump suction pressure changes, the apparent pump performance changes. Therefore, it is necessary to detect this pump suction pressure with a pressure sensor on the pump suction side and use it for calculating the target pressure. As described above, when the estimated terminal pressure constant control is performed, it is essential to use the suction side pressure sensor in addition to the discharge side pressure sensor, which causes an increase in apparatus cost.

  In the direct water supply method, if the pump is continuously operated in a state where the suction pressure is reduced, the pressure drop in the water main (distribution pipe) is promoted. Therefore, the suction pressure is detected by a pressure sensor, and when the suction pressure falls below a specified value, the pump is stopped by a suction pressure drop alarm. Further, when the suction pressure is restored, the alarm is automatically reset and the pump is restarted. Thus, in order to detect an abnormal pressure drop in the water main, it is essential to provide a suction-side pressure sensor, which has been a factor in increasing the device cost.

  As described above, when the conventional direct-connection type water supply device is applied to water supply to a relatively low-rise building with a small scale, it is inevitably excessive in terms of the number of pumps, pressure sensors, etc., and the device cost and running This is a big problem in cost.

  The present invention has been made in view of such problems of the prior art, and can reduce the introduction cost and running cost of the apparatus, and is particularly suitable for water supply to a relatively low-rise building with a small scale. An object is to provide a directly connected water supply device.

The water supply device of the present invention includes a suction pipe connected to a water distribution pipe, a single pressure pump connected to the suction pipe, a motor for driving the pressure pump, and a discharge side of the pressure pump. A connected discharge pipe; a bypass pipe that bypasses the pressure pump and is connected to the suction pipe and the discharge pipe; and a discharge pressure detector that detects a discharge pressure of the fluid pressurized by the pressure pump; A control device for controlling the pressurizing pump, and the control device calculates a target pressure for making the terminal pressure of the pressurized fluid supply destination substantially constant regardless of the discharge flow rate of the pressurizing pump. And a rotation speed control unit that controls the rotation speed of the motor so that the discharge pressure detected by the discharge pressure detector matches the calculated target pressure. Is.
In addition, as a pressurizing pump, it is preferable to use an efficient pump when there is a low head and a relatively high flow rate.

  According to the present invention, in the case of a relatively low-rise and small-scale housing complex, in most cases, water can be supplied only by the pressure of the water distribution pipe (water main). When water is supplied to the customer and the pressure in the distribution pipe (water main) drops, the customer can be supplied with a single pump. Thus, according to the water supply apparatus which concerns on this invention, since only one pump is required, the introduction cost and running cost of an apparatus can be reduced. According to the present invention, since it is possible to perform the estimated terminal pressure constant control by operating one pump, it is possible to eliminate waste of power such as the constant discharge pressure control.

According to an aspect of the present invention, the bypass pipe is configured by a flexible hose.
According to the present invention, when connecting the bypass pipe and the pump suction side pipe or the pump discharge side pipe, a flexible hose having flexibility is used to absorb an assembly error caused by the connection of a plurality of pipes. can do.

  According to one aspect of the present invention, the control device determines the relationship between the discharge pressure corresponding to the discharge flow rate of the pump for adjusting the end pressure substantially constant, and the minimum pump flow rate corresponding to the minimum required flow rate. The calculation unit for calculating and calculating from the rotation speed to the maximum rotation speed of the pump corresponding to the maximum required flow rate, and the detected discharge pressure corresponding to the actual required flow rate is determined by the calculation. The rotation speed control unit that controls the rotation speed of the motor so that the discharge pressure conforms to the relationship described above, and the calculation unit has a maximum required flow rate required at the supply destination for operating the pump. It is configured to recalculate the maximum rotation speed according to the increased maximum flow rate when it changes in a large direction, and the maximum rotation speed is initialized according to a preset schedule. Characterized in that it is configured.

  If comprised in this way, a calculating part will recalculate according to this large maximum flow volume, when the maximum required flow rate which requires the maximum rotational speed in the said supply destination changes in a big direction during the driving | operation of a pump. The maximum rotational speed is configured to be initialized according to a preset schedule, so that the state where the estimated terminal pressure control is performed for a large flow rate rather than a normal flow rate continues for a long period of time. It can be avoided.

  According to one aspect of the present invention, the control device determines the relationship between the discharge pressure corresponding to the discharge flow rate of the pump for adjusting the end pressure substantially constant, and the minimum pump flow rate corresponding to the minimum required flow rate. The calculation unit for calculating and calculating from the rotation speed to the maximum rotation speed of the pump corresponding to the maximum required flow rate, and the detected discharge pressure corresponding to the actual required flow rate is determined by the calculation. The rotation speed control unit for controlling the rotation speed of the motor so that the discharge pressure conforms to the relationship described above, and the calculation unit shows the relationship between the required flow rate and the discharge pressure of the pump. It is obtained by calculating with respect to an assumed maximum suction pressure.

  According to the present invention, the pump suction pressure changes with the pressure fluctuation of the water distribution pipe (water main), but the target pressure is calculated using the maximum suction pressure assumed for the pump. Even if the pressure changes, the pump can be operated without lowering the amount of water. Therefore, it is not necessary to provide a suction side pressure sensor for detecting the pressure of the water distribution pipe (water main) on the suction side of the pump, and the cost of the water supply device can be reduced.

According to one aspect of the present invention, there is provided a pressure switch for detecting that the suction pressure of the fluid flowing into the pressurizing pump has become a predetermined pressure.
According to the present invention, when the pressure of the water distribution pipe (water main) drops and the pump suction pressure falls below a predetermined value, this suction pressure drop can be detected by the pressure switch. There is no need to provide a pressure sensor, and the cost of the water supply device can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the introduction cost and running cost of an apparatus can be reduced, and water supply can be effectively implement | achieved especially to a building with a comparatively low floor and a small scale.

  Hereinafter, embodiments of a water supply apparatus according to the present invention will be described in detail with reference to FIGS. 1 to 10. 1 to 10, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic diagram showing a basic configuration of a water supply apparatus 1 of the present invention. The water supply apparatus 1 of the present invention can be suitably used for a relatively low-rise, small-scale housing complex, etc., and normally supplies water to the end demand destination only by the pressure (normal pressure) of the water main (distribution pipe) 2. It is suitable when possible.

  As shown in FIG. 1, the water supply device 1 includes a single pressurizing pump 3, a motor 4 that drives the pump 3, a pump suction pipe 5 connected to the suction port of the pump 3, and a discharge port of the pump 3. And a bypass pipe 7 which bypasses the pump 3 and connects the pump suction pipe 5 and the pump discharge pipe 6. The pump suction pipe 5 is connected to an upstream water supply pipe 30 extending from the water main pipe (distribution pipe) 2 and has a device main body suction port 5a for sucking water into the device. The pump discharge pipe 6 is connected to a downstream water supply pipe 31 extending to the water supply terminal of the consumer, and has an apparatus main body discharge port 6a for discharging water supplied by the pump 3 from the apparatus. The pump suction pipe 5 is provided with a check valve 8 and a gate valve 9. The pump discharge pipe 6 is provided with a flow switch 10, a pressure tank 11, a pressure sensor 12, and a gate valve 13. The bypass pipe 7 is provided with a check valve 14 for preventing a back flow from the discharge side to the suction side and a pressure switch 15 for detecting the suction side pressure.

  The water supply device 1 includes a control device 40 that controls the pump 3, the motor 4, and other devices. The control device 40 includes an inverter device 50 that controls the rotation frequency (rotation speed) of the motor 4 at a variable speed, and the water supply device 1. Is provided with a display operation unit (not shown) for displaying various operation settings such as input of operation conditions.

  A pressure sensor 12 provided in the pump discharge pipe 6 detects water pressure (discharge pressure) in the pump discharge pipe 6, and an output signal of the pressure sensor 12 is sent to the control device 40. The pressure switch 15 provided in the bypass pipe 7 is activated when the water pressure of the water main pipe 2 becomes a predetermined low pressure, and the output signal of the pressure switch 15 is sent to the control device 40. It is done.

  As described above, at the normal time, sufficient water can be supplied to the customer by the pressure of the water main 2 (normal pressure), so the pump 3 of the water supply device 1 is stopped. The tap water is mainly supplied to the terminal customer through the upstream side water supply pipe 30, the bypass pipe 7, and the downstream side water supply pipe 31. A part of the tap water passes through the pump suction pipe 5, the pump 3, and the pump discharge pipe 6 and reaches the downstream water supply pipe 31.

  Here, if the pressure of the water main 2 is slightly reduced due to an increase in the amount of water supply in the area, the pressure of the water main 2 alone is not sufficient to secure sufficient water supply at the high-end demand destination. It may become. In such a case, the pressure sensor 12 provided in the pump discharge pipe 6 detects that it has fallen below a preset starting pressure, and in response to this, the control device 40 activates the pump 3. At this time, the pump 3 is soft-started in order to suppress fluctuations in the pressure of the water main pipe 2.

  After the pump 3 is started, the rotation speed of the pump 3 is controlled by the inverter device 50 so that the pressure detected by the pressure sensor 12 matches the calculated target pressure, and the estimated terminal pressure constant control is performed ( Will be described later). When the water pressure in the water main pipe 2 becomes a predetermined low pressure during the operation of the pump, the pressure switch 15 is activated to stop the pump 3. When the water pressure in the water main 2 is restored, the operation of the pressure switch 15 is released, and the pump can be operated.

  2 and 3 are views showing the appearance of the water supply apparatus shown in FIG. 1, FIG. 2 is a plan view of the water supply apparatus, and FIG. 3 is a partial sectional front view. As shown in FIGS. 2 and 3, the pump 3, the motor 4, the pressure tank 11, and the control device 40 are placed on the unit base 20, and these devices are fixed by a fixture such as a bolt. And the unit cover 21 is provided so that these apparatuses (the pump 3, the motor 4, the pressure tank 11, the control apparatus 40), the check valve 8, and the pressure sensor 12 (pressure detector) may be covered. Further, a bypass pipe 7 is arranged so as to bypass each device branched from the pump suction pipe 5 and the pump discharge pipe 6 and covered with the unit cover 21. The pump suction pipe 5 and the pump discharge pipe 6 are respectively provided with flange portions 5f and 6f at each end so that they can be connected to the upstream water supply pipe 30 and the downstream water supply pipe 31 (not shown in FIGS. 2 and 3). I have.

  In the present embodiment, the pump 3 is composed of a cascade pump. The cascade pump is a pump that is also called a friction pump, and includes an impeller 23 that is formed as a disk having a large number of grooves on the periphery. The pump 3 is configured by housing an impeller 23 in a pump casing 22, and a pump casing cover 24 is attached with bolts on the front surface of the pump casing 22 viewed from the direction of the impeller shaft. When removed, the impeller 23 can be accessed for easy maintenance and inspection.

  A steam / water separation chamber 25 is provided on the downstream side of the impeller 23, and the flow switch 10 is disposed on the downstream side of the steam / water separation chamber 25, and the pressure sensor 12 is disposed in the vicinity thereof. On the upper part of the pressure tank 11 in the vertical direction, a faucet 26 is provided.

  4 is a plan view showing another embodiment of the water supply apparatus shown in FIG. A water supply device 1 shown in FIG. 4 is similar to the water supply device shown in FIG. 2, one pressurizing pump 3, a motor 4 that drives the pump 3, and a pump suction pipe 5 that is connected to a suction port of the pump 3. A pump discharge pipe 6 connected to the discharge port of the pump 3, and a bypass pipe 7 that bypasses the pump 3 and connects the pump suction pipe 5 and the pump discharge pipe 6. In the embodiment shown in FIG. 2, the pump suction pipe 5 is integrally provided with the branch valve 9 and the branch pipe for connecting the bypass pipe 7, but in the embodiment shown in FIG. 4, the pump suction pipe 5 is provided. The gate valve 9 is connected to the gate valve 9 by screwing, and the suction side branch pipe 16 for connecting the bypass pipe 7 is connected to the gate valve 9 by screwing. Further, in the embodiment shown in FIG. 2, the pump discharge pipe 6 is integrally provided with the branch valve 13 and the branch pipe for connecting the bypass pipe 7, but in the embodiment shown in FIG. A gate valve 13 is connected to the pipe 6 by screwing, and a discharge side branch pipe 17 for connecting the bypass pipe 7 is connected to the gate valve 13 by screwing.

  The suction side branch pipe 16 is connected to an upstream water supply pipe 30 (see FIG. 1) extending from the water main pipe (distribution pipe) 2 and has a device main body suction port 5a for sucking water into the device. Further, the discharge side branch pipe 17 is connected to a downstream side water supply pipe 31 (see FIG. 1) extending to the water supply end of the consumer, and has an apparatus main body discharge port 6a for discharging water supplied by the pump 3 from the apparatus. Have.

  In the embodiment shown in FIG. 4, the bypass pipe 7 is composed of a curved pipe (elbow) 7A made of stainless steel casting or the like and a flexible hose 7B made of a flexible metal hose or the like. The curved pipe 7A is integrally provided with a check valve 14 and a pressure switch 15. The curved pipe 7A is flange-connected to the suction side branch pipe 16, and the flexible hose 7B is connected to the discharge side branch pipe 17 and the check valve 14 by screwing.

According to the water supply apparatus shown in FIG. 4, water can be supplied only by the bypass flow path including the bypass pipe 7 by closing the two valves of the gate valve 9 and the gate valve 13 during maintenance of the pump.
According to the water supply device shown in FIG. 4, the suction side pipe line is configured by connecting the pump suction pipe 5, the gate valve 9, and the suction side branch pipe 16 to each other, and the discharge side pipe line is pumped. Since the discharge pipe 6, the gate valve 13 and the discharge side branch pipe 17 are connected to each other, commercially available valves can be used for the gate valve 9 and the gate valve 13. Reduction can be achieved. Further, the bypass flow path is constituted by a bent tube 7A having a mounting portion of the pressure switch 15 and a space where the check valve 14 is built, and a flexible hose 7B.

  The suction side is screwed or flanged in the order of the pump suction pipe 5, the gate valve 9, the suction side branch pipe 16, and the curved pipe 7A. The discharge side is the pump discharge pipe 6, the gate valve 13, and the discharge side branch pipe 17 in this order. Since the connection is screwed in, every time the number of connections is repeated, the coaxiality of the pipe line, the perpendicularity of the flange surface, the joint dimensions, etc. will gradually accumulate, but the flexible connection that finally connects the above two pipe lines The assembly error accumulated by the hose 7B is absorbed.

  The bypass flow path is composed of the curved pipe 7A and the flexible hose 7B. By making the curved pipe 7A shorter and the flexible hose 7B longer, the curved pipe 7A made of stainless steel casting or bronze casting is manufactured. Making it easy. And it has the structure advantageous also in terms of cost by using a commercially available flexible hose for the flexible hose 7B.

  In the embodiment shown in FIG. 4, the curved pipe 7A is provided on the suction side and the flexible hose 7B is provided on the discharge side. However, the structure on the suction side and the structure on the discharge side are interchanged, and the flexible hose 7B is provided on the suction side. Alternatively, the curved pipe 7A may be provided on the discharge side.

Next, with reference to the flowchart of FIG. 5, it demonstrates per control apparatus and effect | action of a water supply apparatus of this Embodiment.
Connected to the tip of the pump discharge pipe 6 is a downstream water supply pipe 31 extending to the water supply terminal of the consumer. Valves 32c-1, 32c-2, 32c-3, etc., such as faucets, are attached to the end 31a of the downstream water supply pipe 31. The estimated end pressure is an estimate of the pressure at the end 31a. This is the highest and / or end of the longest pipe and is the part that governs the target discharge pressure of the pump. By controlling the discharge pressure of the pump to a predetermined target pressure, a desired amount of water can be discharged from the valves 32c-1, 32c-2, 32c-3,.

  In FIG. 5, a signal indicated by (D) in the signal line is a digital signal, and a signal indicated by (A) is an analog signal. The inverter device 50 (indicated by a two-dot chain line) includes an IPM (Intelligent Power Module) 52 that supplies driving power to a DC brushless motor as the motor 4, a DCBL controller 53 that controls the IPM 52, and a microcomputer 54 that controls the DCBL controller 53. Prepare.

The microcomputer 54 includes a CPU 55, a memory 56 that stores a program used by the CPU 55, and an I / O 57 that is a relay device that receives an external input signal and outputs the signal to the outside.
Since the pressure tank 11 is installed on the downstream side of the flow switch 10, the flow switch 10 does not detect the water flow supplied from the pressure tank 11 when the pump 3 is stopped.

A DCBL (direct current brushless) controller 53 receives the feedback of the magnetic pole signal from the direct current brushless motor 4, synchronizes the frequency of the drive power with the rotational speed of the direct current brushless motor 4, and forms a rotating magnetic field in the stator of the motor 4.
A DCBL (direct current brushless) controller 53 transmits a PWM waveform signal to the IPM 52. The IPM 52 supplies power corresponding to the signal (with the same waveform) to the DC brushless motor 4.

  The pressure signal from the pressure sensor 12 is input to the pressure controller unit 58, and the pressure controller unit 58 sends a speed set value to the speed controller unit 59. The speed controller 59 receives the feedback of the rotation speed of the motor 4 and outputs a control signal (voltage signal Ve) corresponding to the difference between the set speed and the actual operation speed to the DCBL controller 53. That is, the speed controller 59 constitutes a rotational speed controller that controls the rotational speed of the motor 4 so that the discharge pressure detected by the pressure sensor (discharge pressure detector) 12 matches the calculated target pressure. .

  The IPM 52 supplies drive power to the motor 4 as described above. The IPM 52 receives the PWM drive waveform signal from the DCBL (direct current brushless) controller 53 and generates power having the same waveform as the signal waveform. The IPM 52 is an amplifier. The IPM 52 has a built-in power transistor. An ON / OFF signal is input to the gate of the IPM 52, and the same ON / OFF power as that signal is output. The power transistor performs a so-called switching operation.

  The IPM 52 causes the power transistor to perform a switching operation at the same cycle as the on / off signal from the DCBL controller 53. As a result, the on-off generation cycle is constant (t1), the ON duration W is wide, W1, W2,... Is obtained. Although this direct current power is direct current, the effective value is low in the portion where the time width W is narrow, the high value is high in the wide portion, and the power is equivalent to the alternating current power having a period of T as a whole.

Further, when the signal voltage Ve is high, the time width W is widened as a whole, so that the overall effective value when viewed as AC power is high. In this way, the rotational speed is maintained even when the load on the pump 3 increases.
The DCBL controller 53 receives the voltage signal Ve from the speed controller unit 59 in the CPU 55. The voltage signal Ve is a digital signal when it is output from the CPU 55, but is converted into an analog signal (0 to 5 V) by a D / A converter (digital / analog converter) 60 provided in the middle, and the DCBL controller 53. To enter. The CPU 55 has an IC structure. The duty ratio determined by the voltage signal Ve is determined by one set for one period instead of one wide and narrow width.

  On the other hand, the DCBL controller 53 receives the feedback of the magnetic pole signal from the motor 4 and adjusts the period T of the PWM drive waveform signal that is an output signal. This is because if the rotational speed of the rotor (not shown) of the motor 4 is not equal to the rotational speed of the rotating magnetic field of the stator (not shown), so-called step-out occurs.

  For example, when the load of the pump 3 increases and the rotation of the rotor of the motor 4 falls, it is fed back to the DCBL controller 53, and the rotation speed of the rotating magnetic field of the stator also decreases. At this time, since the discharge pressure of the pump decreases, the pressure controller unit 58 and the speed controller unit 59 work to increase the voltage signal Ve, and as described above, the effective voltage of the driving power from the IPM 52 increases. The output of the motor 4 increases, the rotational speed of the pump 3 is maintained, and the discharge pressure is maintained.

  The period T of the PWM drive waveform, which is the output of the DCBL controller 53, is variable, that is, the frequency is variable, and eventually the rotational speed of the motor 4 is variable, so that an appropriate discharge pressure is obtained according to the flow rate of the pump 3. Control that can be obtained is possible.

  The CPU 55 includes a speed controller unit 59, a pressure controller unit 58, an estimated terminal pressure constant control calculation unit 61, and an automatic start / stop control unit 62. The estimated terminal pressure constant control calculation unit 61 constitutes a calculation unit that calculates a target pressure for making the terminal pressure of the pressurized fluid supply destination substantially constant regardless of the discharge flow rate of the pressurizing pump 3. The estimated terminal pressure constant control will be described with reference to another drawing.

  A set speed signal (digital signal) from the pressure controller 58 is input to the speed controller 59. The digital speed signal output from the DCBL controller 53 is fed back. The digital speed signal here is a pulse output of the number of pulses per time proportional to the rotation speed.

  The speed controller 59 performs PI (proportional integration) control so that the difference between the set speed from the pressure controller 58 and the speed fed back becomes zero. A set speed signal from the pressure controller 58 is input to the speed controller 59. An analog pressure signal from the pressure detector 12 that detects the discharge pressure of the pump 3 is converted into a digital signal by an A / D converter (analog / digital converter) 63 and input to the pressure controller 58. On the other hand, a set pressure signal (digital signal) is input from the estimated terminal pressure constant control calculation unit 61.

The pressure controller 58 adjusts the set speed signal so that the discharge pressure of the pump 3 becomes the set pressure based on the set pressure signal. That is, when the pump discharge pressure decreases, the set speed is adjusted to increase. This is also PI control.
Since the speed controller unit 59 is provided, it is possible to set to suppress the upper limit of the maximum rotation speed of the pump 3. That is, control for preventing overspeed is possible.

  Further, since the speed controller unit 59 is provided, the set speed signal input thereto can be used as a rotation speed signal used in the estimated terminal pressure constant control calculation unit 61. Note that the speed signal from the DCBL controller 53 may be used for the above purpose. The calculation unit 61 for the estimated terminal pressure constant control will be described later.

The CPU 55 has an automatic start / stop control unit 62, receives an automatic start / stop signal from the outside, and transmits a stop signal to the speed controller unit 59 and the DCBL controller 53.
The CPU 55 is a core component of the microcomputer. A program for the CPU 55 to calculate is stored in a memory 56 in the microcomputer 54.

  As described above, the CPU 55 includes the pressure controller 58, the speed controller 59, the estimated terminal pressure constant control calculation unit 61, and the automatic start / stop control unit 62. The control program and calculation stored in the memory 56 are included in the CPU 55. Arithmetic processing is performed by the program. The DCBL controller 53 is composed of an IC and receives various information signals.

  The estimated terminal pressure constant control will be described with reference to the pump operation characteristic curve diagram of FIG. The horizontal axis is the amount of water, the vertical axis is the head, that is, the head (hereinafter also referred to as “pressure” as appropriate), and the curve Nx is an operation characteristic with a constant pump rotational speed. Here, the resistance curve R is a pipe loss according to the amount of water used from the pump 3 to the end of the customer, and is a curve proportional to the square of the amount of water used when the point where the water amount Q is 0 is the origin. . Therefore, in order to control the pressure on the discharge side of the pump 3 to be constant, the rotation speed of the pump is set to No (corresponding to Nmax described later) and Nb ′ so that the pressure Pa on the discharge side of the pump 3 becomes constant. It may be controlled between (the deadline pressure is a performance curve of Pa). When such control is performed, the pressure at the end becomes more than necessary at the minimum flow rate. On the other hand, in the estimated terminal pressure constant control, it is necessary to allow for the pipe loss (indicated by the resistance curve R) according to the amount of water used. Therefore, considering this loss, the pump rotation speed is set to No and Nb (the cutoff pressure is Pb). Performance curve). At an intermediate flow rate, operation is performed at an intermediate rotational speed Na (corresponding to N described later). The discharge pressure of the pump changes along the resistance curve R.

  The estimated terminal pressure constant control calculation unit 61 described above calculates a set pressure f (N) that rides on the resistance curve R according to the rotational speed N of the pump 3 and calculates the set value f (N). Is given to the pressure controller 58 as a set value.

  The water supply apparatus 1 sets a lower limit of the amount of water used, and when the flow switch 10 detects the lower limit value, the microcomputer 54 operates to stop the motor 4 and thus the pump 3. Thereafter, when water is used, water is supplied from the pressure tank 11 for a while, but when the water in the pressure tank 11 decreases and the pressure further decreases, the pressure sensor 12 detects this, and the microcomputer 54 The motor 4 is started.

  At this time, when the amount of water is reduced and the motor 4 is stopped, the discharge pressure is increased by temporarily increasing the operation speed of the pump so that sufficient water is stored in the pressure tank 11. Good. The pump 3 may be stopped due to a decrease in the water flow rate based on the lower limit value of the rotation speed without depending on the flow switch 10.

  The first embodiment of the present invention will be described with reference to the pump operation characteristic curve diagram of FIG. First, the estimated terminal pressure constant control will be described. In the figure, the horizontal axis is the amount of water Q, and the vertical axis is the head H or pressure. The water supply apparatus according to the present embodiment includes a control device that performs control so that the required pressure at the end is substantially constant by controlling the control target pressure.

In this water supply device, a data table (not shown) that stores the pressure value at each rotational speed of the pump at the minimum required flow rate (typically zero flow rate “tightened state”), and the required end pressure at the required maximum flow rate. The control target pressure for each pump rotation speed can be determined by using the pump rotation speed and pressure value data (points Pa and Nmax1 in FIG. 7) during discharge.
Alternatively, a coefficient of a relational expression (typically a quadratic equation) between the deadline pressure and the rotation speed may be stored, and a value (for example, Nb) necessary for calculating the resistance curve may be calculated from the equation.

  In order to define the operating curve SV = f (N) (SV is the target pressure) on the N-H coordinate (not shown), it is only necessary to determine two points, and one of them is the deadline. There is no need. In short, two points should be selected from the points that should be on the driving curve. However, it is generally only the point of the maximum required flow rate and the deadline that can define the points that should be on the operation curve when the operation curve is not fixed. Otherwise, the relationship between the flow rate, the rotational speed, and the discharge pressure is unknown when the operation curve is undefined. In other words, the operation curve defines the relationship between the flow rate, the rotational speed, and the discharge pressure. However, by installing a pressure gauge at the end and adjusting the rotation speed so that the actually measured pressure becomes Pb, an intermediate point can be adopted as a point for defining the operation curve.

That is, in the drawing, a resistance curve R ₁ , which is a line connecting the point of the terminal pressure Pb (rotational speed Nb) in the deadline state and the point of the pump discharge pressure Pa (rotational speed Nmax1) allowing for pipe loss at the maximum flow rate, is set. To do. The resistance curve is almost a quadratic curve on the QH coordinate. In order to obtain the line, it may be approximated by one straight line connecting the two points or two straight lines bent at an intermediate point on the NH (rotational speed-lift) coordinate. When this is projected onto the QH coordinates, a quadratic curve is obtained.

  Here, Nmax (required rotation speed at the required maximum water amount) can be obtained in advance by design calculation and input. However, even if it is not known in advance, the present apparatus can be operated and controlled as follows.

The inverter device 50 includes a not-shown maximum rotation speed storage device (not shown). It can be calculated by setting the resistance curve R ₁ on the basis of the maximum rotational speed stored here. If there was no appropriate maximum rotation speed data in the previous maximum rotation speed storage device, a predetermined target pressure was output for a predetermined period of time, and operation was performed at a constant target pressure after a certain period of time. The estimated terminal pressure constant control calculation unit 61 is configured so that the control target pressure can be appropriately calculated using the maximum rotation speed at the time.

Here, when there is no appropriate maximum rotation speed data in the previous maximum rotation speed storage device, there is no maximum rotation speed data in the previous maximum rotation speed storage device immediately after the power is turned on, or noise. This is a case where the data is impossible (30000 Hz or data that is not a numerical value), but is not the data of the appropriate maximum rotation speed. , it is possible to determine the resistance curve R ₁ where now as Nmax maximum rotational speed therebetween, the speed data is obtained. Specifically, the operation is performed with target pressure = Pa for a period in which there is no appropriate maximum rotation speed data and a period in which the current normal rotation speed exceeds the previous maximum rotation speed and is increasing.

Further, when the maximum rotational speed Nmax even after transfer to those controlled by the resistance curve R ₁ is changed, it is possible to correct the resistance curve R ₁ underlying the control operation accordingly. That is, when a normal rotation speed exceeding the previous maximum rotation speed is input, the value of the maximum rotation speed is sent to the estimated terminal pressure constant control calculation unit 61, and the relationship with the control target pressure for each rotation speed of the pump is determined. Can be reset.

  The above will be specifically described. For example, the substantial maximum rotational speed of the pump is usually 50 Hz (or 60 Hz), but depending on the rating on the user side, there is an appropriate value for the maximum control value of 50 Hz or less. The appropriate value is considered to be the point where the rotational speed was actually increased to the maximum when the pump was supplied with the rotational speed controlled.

Here, when a normal rotational speed exceeding the previous maximum rotational speed is input, for example, while calculating the control target pressure according to the resistance curve R ₁ at a certain Nmax of 50 Hz or less (assuming 45 Hz). When operating, the rotational speed of the pump increased to 47 Hz. In other words, the rotational speed exceeding the previous maximum rotational speed (Nmax = 45 Hz) was input. The normal rotation speed here means, for example, a rotation speed that is 50 Hz or less (or 60 Hz or less) and that is not an abnormal value (30000 Hz or non-numeric data) that is impossible to control because of data rewriting due to noise or the like. In addition, the value of the maximum rotation speed (47 Hz in the above example) can be sent to the estimated terminal pressure constant control calculation unit 61 and the relationship with the control target pressure for each rotation speed of the pump can be reset. This means that the resistance curve R ₁ is recreated at 47 Hz and controlled according to the subsequent resistance curve R ₂ .

Whether or not the rotation speed is normal can be determined to be normal when both of the following conditions are satisfied, for example.
(1) Rotational speed command value ≦ Rated rotational speed (value corresponding to 50 Hz or 60 Hz in an induction motor pump)
(2) The relationship between the pressure and the rotational speed is in an equilibrium state or a state close thereto. Specifically, the state is identified by the following expression in the program. (Absolute value ≦ 0.3m of difference between target pressure (SV value of pressure controller) and discharge pressure (PV value of pressure controller))

  The rotation speed varies depending on how water is used. For example, when water is used at its maximum, the rotation speed becomes the maximum rotation speed. Further, when water is used and this time 47 Hz becomes 49 Hz, the maximum rotation speed value (49 Hz) is sent to the estimated terminal pressure constant control calculation unit 61 to control the target pressure for each rotation speed of the pump. (Resistance curve R) is reset. However, it is not reset when the rotation speed becomes abnormal such as 1000 Hz.

However, there is a case where a part of the customer's piping is removed for cleaning and the pump is operated. In such a case, the piping resistance decreases.
In Figure 7, the resistance curve R ₂ is assumed to be such a case. Even after the cleaning is finished and the piping is attached, the estimated terminal pressure constant control calculation unit 61 calculates the target pressure from the resistance curve R _2, so that the rotation speed of the pump is lower than the desired rotation speed. .

Therefore, in the first embodiment of the present invention, the maximum rotation speed is initialized according to a preset schedule.
The first embodiment will be described in more detail with reference to the flowchart of FIG.
S1: First, the pump is started.
S2: The pump is operated at an initial rotation speed N.
S3: Based on the operation rotational speed N of the pump, the estimated terminal pressure constant control calculation unit 61 calculates the target discharge pressure. The obtained target discharge pressure is input as a set pressure to the pressure controller 58 (see FIG. 5).

S4: On the other hand, the pressure sensor 12 detects the discharge pressure of the pump operated at the operation rotational speed N. The detected pressure is input to the pressure controller unit 58.
S5: The pressure controller 58 compares the target discharge pressure obtained in S3 with the actual discharge pressure detected in S4.
S6: The pressure controller unit 58 is a proportional-integral (PI) control regulator in the present embodiment. Therefore, based on the comparison in S5, the set value of the rotation speed of the pump is determined in a direction in which the difference between the two becomes zero and is output to the speed controller unit 59. For example when the pump discharge pressure is operated at a rotational speed N is lower than the target pressure determined by the resistance curve R ₁ raises the set value of the rotational speed. In this way, stable operation is continued when the target discharge pressure is equal to the detected actual discharge pressure.

S7: As described above, in the initial state after the pump is installed on the site, the estimated terminal pressure constant control calculation unit 61 is operated with the target pressure = Pa, and the maximum rotation speed during that time is set to Nmax. When the data becomes thus obtained to determine the resistance curve R _1.
S8: In the water supply apparatus of this embodiment, it is determined as follows whether or not the water supply apparatus has reached the initialization time while the operation is continued. That is, after the installation is started and the operation is started, or after the previous initialization, the resistance curve R ₂ is restored when the pump is stopped within 4 days after the passage of 13 days (about 2 weeks) as the first predetermined period. Set, that is, initialize. In addition, when the pump does not stop within the above four days, it is configured to forcibly initialize.

If the stop is within 13 days from the previous initialization, the initialization is not performed. Therefore, too frequent initialization can be avoided. Further, if the pump is stopped after 13 days, it is initialized when the pump is stopped, so that initialization during operation can be avoided, and it is possible to avoid a sudden change in the flow of water while the consumer is using water. Also when no pump is stopped during the 4 days, so forcibly initialized, even resistance curve had become unnatural R _2, where it can return to the original resistance curve R _1.

S9: If it is not the initialization time (S8 is No), it is determined whether the pump maximum flow rate has exceeded the past maximum flow rate. If not (S9 is No), the pump operation is continued as it is. (Return to S2)
S10: If the pump maximum flow rate exceeds the past maximum flow rate (S9 is Yes), a calculation curve (for example, R ₂ ) is set based on the new maximum flow rate. Maximum flow rate set based on that, specifically, is that define a curve R ₂ based on the pump rotational speed Nmax2 to a pressure Pa discharge pump in anticipation piping losses at its maximum flow rate.

With reference to FIG. 9, a second embodiment of the present invention will be described. This Embodiment is a water supply apparatus suitable for the use from which the suction pressure of a pump changes.
FIG. 9 (a) shows a case where the resistance curve R (Ps) is first set at the suction pressure Ps in the estimated terminal pressure constant control computing unit 61. FIG. The resistance curve R (Ps) is set between the point of the deadline pressure Pb (rotational speed Nb (Ps)) and the point of maximum flow rate and pressure Pa (rotational speed Nmax). It is assumed that Ps is in a state where the pressure of the water main pipe 2 is low.

  Next, it is assumed that the pressure of the water main 2 is increased to Ps ′ higher than Ps. Since the vertical axis P of the diagram indicates the discharge pressure, the performance curve moves upward in the figure if the suction pressure of the pump increases. That is, when Pb is constant and Pa is constant, the resistance curve R moves to the right in the figure. In other words, the resistance curve R (Ps ′) is positioned below the resistance curve R (Ps).

  Therefore, although the pressure at the main water pipe 2 is low and the estimated terminal pressure is originally the desired pressure, when the pressure at the water main pipe 2 rises and the suction pressure of the pump increases, the estimated terminal pressure is calculated to a low value. Will be. That is, as the suction pressure increases, a phenomenon occurs in which the pump discharge pressure decreases as a result of the constant control of the estimated end pressure. The discharge pressure drops despite the pump's ability. Also, the desired amount of discharged water cannot be obtained.

  For example, when operating at the maximum required flow rate, the estimated end pressure should be Pa, as shown in (a). That is, it should be operated at the intersection of the performance curve of Nmax (Ps) and the pressure Pa. However, as a result of the resistance curve moving to R (Ps ′), the estimated end pressure becomes the pressure (lower than Pa) at the intersection of Nmax (Ps) and the resistance curve R (Ps ′). As a result of such control, the pressure and water amount at the intersection of the performance curve N (<Nmax (Ps)) and the resistance curve R (Ps ′) in the figure, not the original performance curve Nmax (Ps), are eventually lowered.

In 2nd Embodiment of this invention, as shown in (b), the resistance curve R is set with respect to the highest suction pressure assumed about the said water supply apparatus.
If comprised in this way, since the suction pressure of a pump will only fall, the performance curve will move below in the figure. As a result, the resistance curve R moves in the left direction in the figure, upward in terms of the same amount of water. As a result of such movement, as the suction pressure decreases, the estimated end pressure constant control results in the pump discharge pressure becoming higher than the desired pressure, and the discharge pressure is low despite the pump's ability. There is no operation, and in other words, the desired amount of discharged water cannot be obtained. The control as described above can be performed without using the suction pressure detecting means.

  A third embodiment of the present invention will be described with reference to the pump operation characteristic curve diagram of FIG. In this embodiment, the maximum rotation speed is initialized according to a preset schedule, but the suction pressure is not set to the assumed maximum suction pressure of the pump. In this figure, the vertical axis is represented by H (lift head) instead of P (pressure), but the essence does not change. In the figure, the setting of the driving curve is displayed as Automax. The operation curve (Ps) means the resistance curve R (Ps) already described.

(1) First, as shown in (a), an operation curve (Ps) is set with respect to the suction pressure Ps. The operating curve (Ps) is the point 1 where the Nmax (Ps) pump characteristic curve intersects the H = Pa straight line (parallel to the Q axis) and the Nb (Ps) pump characteristic curve and the H = Pb straight line (Q axis). Is a curve connecting the points 2 intersecting with each other), that is, an operation curve (Ps).
(2) Next, as shown in (b), it is assumed that the suction pressure rises from Ps to Ps ′. Here, Ps <Ps ′. As described above, the operating curve is the point 1 ′ where the Nmax (Ps ′) pump characteristic curve intersects the H = Pa line (parallel to the Q axis) and the Nb (Ps ′) pump characteristic curve and H = Pb. Shift to a curve connecting the points 2 'intersecting with the straight line (parallel to the Q axis), that is, an operation curve (Ps'). Here, the operation curve (Ps) is represented by a broken line, and the new operation curve (Ps ′) is represented by a solid line.
(3) If the point at which the pump characteristic curve of Nmax (Ps) intersects the straight line H = Pa (parallel to the Q axis) is at the maximum valve opening of the building, the maximum valve opening of the building is maintained. First, as a result of the operation curve shifting from the operation curve (Ps) to the operation curve (Ps ′), both the pressure and the flow rate are insufficient.

  (4) In order to alleviate the problem described in (3), Nmax is initialized and the operation curve is reset as shown in (c) and (d). If the point at which the pump characteristic curve of Nmax (Ps) intersects the straight line H = Pa (parallel to the Q axis) is when the valve of the building is fully opened, Nmax is initialized and the operation curve is reset. The operating point cannot be taken to the right beyond this point. If the rotation speed at that time is Nmax ′, the rightmost point of the operation curve (reset operation curve (Ps ′)) obtained as a result of initializing Nmax and resetting the operation curve is Nmax ′ (Ps ′) This point 3 (= 1) intersects the pump characteristic curve of H = Pa and the straight line H = Pa (parallel to the Q axis). In addition, when the pump characteristic curve of Nmax ′ (Ps ′) and the pump characteristic curve of Nmax (Ps) are drawn on the same QH coordinate, they substantially overlap (Nmax ′ <Nmax). On the other hand, the leftmost point of the reset operation curve (Ps ') remains the point where the Nb (Ps') pump characteristic curve intersects the H = Pb straight line (parallel to the Q axis). This initialization and resetting of the operation curve are operations related to Nmax, and Nb is not reset. That is, the operation for obtaining the rotational speed Nb ′ so that the shutoff pressure at the suction pressure Ps ′ is Pb is not performed. By doing so, it is not necessary to obtain the rotation speed Nb ′ at the closing time with the suction pressure Ps ′. Therefore, even if the pumping state has not been stopped since the previous initialization, that is, the operation curve is reset. Can be done. If there is a cutoff state, that is, the pump is stopped between the previous initialization and the current initialization, the suction pressure (approximately Ps ′) at that time may be considered using the rotational speed and discharge pressure at that time. ), The rotational speed Nb ′ at which the cutoff pressure becomes Pb may be obtained, and the operation curve may be reset using the Nb ′ and the aforementioned Nmax ′. Regardless of whether Nb ′ is obtained or not, that is, by any of the above-described methods, the shift of the operating curve due to fluctuations in the suction pressure can be corrected without installing a pressure sensor on the suction side, and It becomes possible to reset the driving curve without inconvenience.

As described above, in the embodiment of the present invention, in a water supply apparatus including a pump, a control target pressure for each rotation speed of the pump is determined in advance (or a function for calculating the control target pressure is determined from the rotation speed), and a change in rotation speed is determined. Accordingly, since the control device for changing the control target pressure is provided, there is no energy loss as in the case where the pump discharge pressure is controlled at a constant pressure.
In addition, it is possible to keep the pipe end pressure substantially constant without requiring a labor-intensive and time-consuming method for individually measuring and controlling each water supply facility.

Further, even when a resistance curve based on a flow rate higher than necessary is set, initialization is performed according to the schedule, so that it is possible to return to normal estimated terminal pressure control at an appropriate time.
Further, it is possible to perform the estimated terminal pressure constant control in a state where the pump performance can be fully exhibited in response to the change in the suction pressure of the pump.

  The water supply device of the present invention is not limited to the embodiment described above, and is not limited to the illustrated examples, and various modifications can be made without departing from the scope of the present invention. Needless to say.

It is a schematic diagram which shows the basic composition of the water supply apparatus of this invention. It is a top view which shows the external appearance of the water supply apparatus shown in FIG. It is a fragmentary sectional front view which shows the external appearance of the water supply apparatus shown in FIG. It is a top view which shows another form of the water supply apparatus shown in FIG. It is a block diagram explaining about the control apparatus and effect | action of a water supply apparatus by embodiment of this invention. It is a driving | operation characteristic figure of a pump explaining estimation terminal pressure fixed control. It is a pump operation characteristic curve figure of a 1st embodiment of the present invention. It is a flowchart explaining the 1st Embodiment of this invention. It is a driving | operation characteristic view of the pump explaining the 2nd Embodiment (water supply apparatus suitable for the use from which a suction pressure changes) of this invention. It is a driving | operation characteristic view of the pump explaining the 3rd Embodiment (the water supply apparatus which resets an operation curve arbitrarily determining suction pressure) of this invention.

Explanation of symbols

1 Water supply system 2 Water main (distribution pipe)
3 Pump 4 Motor 5 Pump Suction Pipe 5a Device Main Body Suction Port 5f, 6f Flange 6 Pump Discharge Pipe 6a Device Main Body Discharge Port 7 Bypass Pipe 7A Curved Pipe (Elbow)
7B Flexible hose 8, 14 Check valve 9, 13 Gate valve 10 Flow switch 11 Pressure tank 12 Pressure detector (pressure sensor)
DESCRIPTION OF SYMBOLS 15 Pressure switch 16 Suction side branch pipe 17 Discharge side branch pipe 20 Unit base 21 Unit cover 22 Pump casing 23 Impeller 24 Pump casing cover 25 Air-water separation chamber 30 Upstream side water supply pipe 31 Downstream side water supply pipe 31a Downstream side water supply pipe Terminals 32c-1, 32c-2, 32c-3 ... Valve 40 Control device 50 Inverter device 52 IPM
53 DCBL controller 54 Microcomputer 55 CPU
56 Memory 57 I / O
58 Pressure Controller 59 Speed Controller 60 D / A Converter 61 Calculation Unit for Estimated Terminal Pressure Constant Control 62 Automatic Start / Stop Control Unit 63 A / D Converter

Claims (5)

A suction pipe connected to the water pipe;
A single pressurization pump connected to the suction pipe;
A motor for driving the pressure pump;
A discharge pipe connected to the discharge side of the pressure pump;
A bypass pipe bypassing the pressurizing pump and connected to the suction pipe and the discharge pipe;
A discharge pressure detector for detecting the discharge pressure of the fluid pressurized by the pressure pump;
A control device for controlling the pressurizing pump,
The control device is detected by the discharge pressure detector and a calculation unit that calculates a target pressure for making the terminal pressure of the supply destination of the pressurized fluid substantially constant regardless of the discharge flow rate of the pressurizing pump. A water supply apparatus comprising: a rotation speed control unit configured to control a rotation speed of the motor so that a discharge pressure coincides with the calculated target pressure.   The water supply device according to claim 1, wherein the bypass pipe is configured by a flexible hose. The control device corresponds to the maximum required flow rate from the minimum rotational speed of the pump corresponding to the minimum required flow rate, and the relationship of the discharge pressure corresponding to the discharge flow rate of the pump for adjusting the end pressure almost constant. The calculation unit for calculating and calculating up to the maximum rotation speed of the pump;
The rotation speed control unit that controls the rotation speed of the motor so that the detected discharge pressure becomes a discharge pressure according to the relationship obtained by the calculation in accordance with the actual required flow rate. Prepared,
The calculation unit is configured to recalculate the maximum rotation speed according to the increased maximum flow rate when the maximum required flow rate required at the supply destination changes in a large direction during operation of the pump. 3. The water supply apparatus according to claim 1, wherein the maximum rotation speed is configured to be initialized according to a preset schedule. The control device corresponds to the maximum required flow rate from the minimum rotational speed of the pump corresponding to the minimum required flow rate, and the relationship of the discharge pressure corresponding to the discharge flow rate of the pump for adjusting the end pressure almost constant. The calculation unit for calculating and calculating up to the maximum rotation speed of the pump;
The rotation speed control unit that controls the rotation speed of the motor so that the detected discharge pressure becomes a discharge pressure according to the relationship obtained by the calculation in accordance with the actual required flow rate. Prepared,
The water supply device according to claim 1 or 2, wherein the calculation unit calculates a relationship between the required flow rate and the discharge pressure with respect to a maximum suction pressure assumed for the pump.   The water supply device according to any one of claims 1 to 4, further comprising a pressure switch that detects that a suction pressure of the fluid flowing into the pressurizing pump has reached a predetermined pressure.

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