JP4678798B2 - Water supply apparatus and water supply apparatus control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water supply apparatus and a water supply apparatus control method, and more particularly to a technique that enables expansion of a pump specification range (allowable use range) within a pump capacity range.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a water supply device that supplies water to buildings, residential high-rise buildings, and the like includes a pump, a pump drive motor, a pressure tank, discharge pressure detection means, and a control device that controls the rotation speed of the pump (that is, the motor rotation speed). Yes. Since the height of each building or building is constant, the required discharge pressure of the water supply device is substantially constant and does not vary greatly. In this type of conventional water supply system, the pump rotation speed at which the pump has a rated output at the rated flow rate is defined as the maximum rotation speed, and the pump rotation speed is sometimes changed so that the required flow rate is generated in the region below the maximum rotation speed. Control every moment.
[0003]
For example, as shown in FIG. 5, the motor drive current becomes the rated current Ic at the intersection of the line 100 having the rotation speed N = N max (maximum rotation speed) and the maximum capacity line 102 of the pump that can actually be used. The pump is used in the area below 100 (that is, the pump specification range). Thus, conventionally, the maximum number of revolutions of a pump in a certain type of water supply device is usually set to, for example, 3,600 rpm in common for all the water supply devices of that model.
[0004]
On the other hand, in Japanese Patent Laid-Open No. 11-287195, in a pump unit having a turbo pump, an AC motor for driving the pump, and an inverter for adjusting the rotational speed of the motor, the relationship between the flow rate of the pump and the generated head is shown in FIG. A pump that presets the relationship of the output voltage (V) with respect to the output frequency (f) of the inverter so as to have an arbitrary characteristic within the rated output, and exhibits the set characteristic while controlling the motor current constant. A characteristic control device is described.
[0005]
[Problems to be solved by the invention]
When the pump is operated only in the pump specification range 101 (allowable use range) below the line 100 shown in FIG. 5, the maximum capacity line 102 and the line 100 at which the motor current becomes the rated current value Ic at each pump rotation speed The area 103 surrounded by is an area where the pump can be operated but is not used at all, and therefore, the capacity of the pump is not fully utilized. As a result, it is difficult to improve the versatility of the water supply device, and a water supply device having an excessive capacity is always adopted for the water supply requirements of buildings and buildings, which is disadvantageous in terms of equipment economy and running cost.
[0006]
In the control technology of the above publication, the pump is operated while the motor current is controlled to be constant (for example, rated current), so that the capacity of the pump and the motor can be fully utilized. It is difficult to say that the control technology is suitable for a device whose load is constantly fluctuating. An object of the present invention is to provide a water supply device and a water supply device control method that enable the pump to be used within the maximum capacity range while appropriately updating the maximum rotation speed of the pump according to the use state of the pump.
[0007]
[Means for Solving the Problems]
The water supply device according to claim 1 is a pump, a pump drive motor, a pressure tank, pressure detection means for detecting a discharge pressure of the pump, and starting or stopping the pump based on a request of a water supply system, and a detected discharge pressure. In a water supply apparatus comprising a control means for controlling the discharge pressure by changing the pump rotation speed so as to achieve a target pressure value, the control means updates the pump maximum rotation speed Nmax to the pump target maximum rotation speed value Nm. The pump rotation speed Nx is controlled so that the pump rotation speed Nx does not exceed the pump maximum rotation speed Nmax, and the operating current value becomes the rated current value at zero discharge flow rate after the water supply device is turned on or after the pressure setting is changed. controls pump speed Nx a preset pump operable maximum speed Nc as the pump target maximum speed value Nm, the rated current is the operating current values during pump operation And it stores the pump speed Nx in a memory of the time was, the feed water system pump and update the pump target maximum speed value Nm in pump speed Nx stored in the memory in the next pump startup requested by It is characterized by controlling.
[0008]
The preset pump rotation speed Nc at which the operation current value becomes the rated current value at a discharge flow rate of zero is the maximum rotation speed at which the pump can be operated, and the control means sets the pump maximum rotation speed Nmax to the pump target maximum rotation speed value Nm. The pump rotation speed Nx is controlled so that the pump rotation speed Nx does not exceed the pump maximum rotation speed Nmax, and after the water supply device is turned on or after the pressure setting is changed, the above-mentioned maximum operable rotation speed Nc is set. controls the pump speed Nx as the target maximum speed value Nm of the pump. Thereafter, the control means, the pump rotational speed Nx is stored in memory, the pump target maximum rotational speed value at the next pump start by the feed water system requests when the operating current value becomes the rated current value during operation of the pump The pump is controlled by updating Nm to the pump rotation speed Nx stored in the memory .
[0009]
In the water supply device, the pressure setting value for the discharge pressure is set according to the installation location and usage conditions, and the pump speed is controlled so that the target pressure value is determined based on the pressure setting value or the pressure setting value. To do. The control means controls the number of revolutions of the pump based on the pressure setting value or the target pressure value, but the operating current value increases as the pump discharge flow rate increases, and the operating current value becomes the rated current value. Is the maximum discharge flow rate. The maximum discharge flow rate decreases as the pressure set value Ps increases.
[0010]
Therefore, the pump speed Nx when the operating current value becomes the rated current value during the operation of the pump is the pump maximum speed reflecting the pressure set value set in the water supply device. The pump rotation speed Nx is stored in the memory, and the pump is controlled by updating the pump maximum rotation speed to Nx at the next pump start-up according to the request of the water supply system, so that the pump usage state (or pressure setting value) The pump can be operated while updating the pump maximum rotation speed so as to conform to the above, and the capacity of the pump can be maximized according to the use conditions of the water supply device.
[0011]
The water supply device control method according to claim 2 is a control means for controlling the discharge pressure by starting or stopping the pump and changing the number of revolutions of the pump based on the requirements of the pump, the pump drive motor, the pressure tank, and the water supply system. The control means updates the pump maximum rotation speed Nmax to the pump target maximum rotation speed value Nm and rotates the pump so that the pump rotation speed Nx does not exceed the pump maximum rotation speed Nmax. control the number Nx, after power-on or after the pressure setting change of the water supply device, the operating current value becomes the rated current value in the discharge flow rate zero preset pump operable maximum speed Nc of the pump target maximum speed value Nm memory a first step of controlling the pump speed Nx, then the pump speed Nx when the operating current value is the rated current during pump operation as A second step of storing, then, during pump start by the water supply system request and a third step of controlling the pump to update the pump target maximum speed value Nm in pump speed Nx stored in the memory It is characterized by this.
[0012]
In the first step, after power up or after a pressure setting change of the water supply device, a pump drivable maximum rotational speed Nc the operating current value is set in advance becomes the rated current value in the discharge flow rate zero as the pump target maximum speed value Nm The pump speed Nx is controlled. Thereafter, in the second step, the pump rotational speed Nx when the operating current value becomes the rated current value during the pump operation is stored in the memory. Thereafter, in a third step, during pump start by the water supply system requirements of the pump target maximum speed value Nm is updated to pump speed Nx stored in the memory to control the pump speed Nx. Therefore, the same effect as in the first aspect can be obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. The present embodiment is an example of a case where the present invention is applied to a water supply device that is installed in a building or a medium- and high-rise residential building and supplies water to each floor in the building or building. In addition, the following description includes the description of the water supply device and the description of the water supply device control method.
[0014]
As shown in FIG. 1, the water supply apparatus 1 includes turbo-type multistage pumps 12 and 13 connected in parallel to a suction pipe 11 connected to a water main, and a three-phase AC motor that drives the pumps 12 and 13, respectively. The check valves 18 and 19 and the gate valves 20 and 21 connected to the discharge pipes 16 and 17 of the pump drive motors 14 and 15 and the pumps 12 and 13 , respectively. A water supply pipe 22 connected to the installed water supply system, a pressure transmitter 23 connected to the water supply pipe 22 for detecting discharge pressure, a pressure tank 24 (water supply accumulator), a control unit 30 for controlling the motors 14 and 15; An operation panel 31 connected to the control unit 30 is provided, and the water supply device 1 is configured as a cabinet-type water supply device incorporated in a cabinet (not shown). There is also.
[0015]
The control unit 30 includes a microcomputer including a CPU 32, a ROM 33 and a RAM 34, an input / output interface 35, motor drive circuits 36 and 37 including an inverter, and the pressure transmitter 23 and the operation panel 31 are connected to the input / output interface 35. Has been. The operation panel 31 is provided with a power switch, a switch for selecting the No. 1 pump 12 and the No. 2 pump 13, an automatic operation switch, a manual operation switch, a stop switch, a display, a pressure setting switch, and other various switches. It has been.
[0016]
The ROM 33 of the microcomputer stores in advance a flow chart of automatic pump operation control shown in the flow charts of FIGS. 3 and 4 and various arithmetic expressions associated with this control. The RAM 34 of the microcomputer is provided with various work memories necessary when the CPU 32 performs the control.
[0017]
Initially, the outline | summary of the pump automatic operation control employ | adopted as this water supply apparatus 1 is demonstrated with reference to FIG. However, the following description demonstrates the case where one pump 12 is drive | operated as an example. A curve 38 in FIG. 2 is a curve connecting a plurality of points at which the operating current value I of the motor 14 becomes the rated current value Ic at a plurality of pump rotation speeds N, and is a maximum capacity line of the pump 12. After the water supply device 1 is turned on, when the discharge flow rate is zero , the maximum operation speed Nc (the pump speed at the point Ac) at which the operation current value I becomes the rated current value Ic is set to the provisional maximum rotation speed N. The pump 12 is controlled as max , the pump maximum rotational speed Nmax is updated to the pump target maximum rotational speed Nm, and the pump rotational speed Nx is controlled so that the pump maximum rotational speed Nmax does not exceed the pump rotational speed Nx . The same applies to the case where the pressure set value Ps is changed and set.
[0018]
Thereafter, the pump rotational speed Nx (however, the pump rotational speed N1 passing through the point A1) when the operating current value I becomes the rated current value Ic during operation of the pump 12 with the pressure set value Ps as P1, for example, is stored in the RAM 34. The pump 12 is controlled by updating the maximum pump speed Nmax to Nx (= N1) when the pump is started next time. In this case, the maximum value of the discharge flow rate is the flow rate corresponding to the point A1, and in order to maintain the discharge pressure at the pressure setting value Ps, control is performed to increase or decrease the pump rotational speed in accordance with increase or decrease of the discharge flow rate.
[0019]
On the other hand, during operation of the pump 12 with the pressure set value Ps as P2, for example, the pump rotational speed Nx when the operating current value I becomes the rated current value Ic at the point A2 (however, the pump rotational speed N2 passing through the point A2) ) Is stored in the memory of the RAM 34, and the pump maximum speed Nmax is updated to Nx (= N2) when the pump is started next time to control the pump 12. Thus, the pump 12 can be operated by setting the range within the maximum capacity in which the pump 12 can operate as the pump specification range (allowable use range), and the pump specification range (use allowable range) can be greatly expanded. .
[0020]
Next, automatic pump operation control for automatically operating the pump 12 will be described with reference to the flowcharts of FIGS. In the figure, symbol Si (i = 1, 2,...) Indicates each step. When this control is started by turning on the power of the water supply device 1, the initial setting necessary to clear the work memory of the RAM 34 is first executed (S 1), and then the discharge flow rate is set as the target maximum rotation value Nm of the pump 12. A pump- operable maximum rotational speed Nc at which the operating current value I becomes the rated current value Ic at zero is set in advance (S2).
[0021]
Next, the pressure set value Ps preset and stored in the memory of the RAM 34 is read (S3), and the detected pressure Pd is read from the pressure transmitter 23 (S4). Next, it is determined whether or not the detected pressure Pd is equal to or lower than a predetermined starting pressure Pk (S5). If Pd ≦ Pk is not satisfied, the pump 12 does not need to be started, and the process returns to S3. Since it is necessary to start the pump 12 when Pd ≦ Pk, the target maximum speed value Nm is given to the pump maximum speed N max (S6), and then the pressure set value Ps is applied to a predetermined arithmetic expression. The target pressure Pt is calculated (S7), and the pump 12 is activated (S8).
[0022]
Next, the detected pressure Pd is read from the pressure transmitter 23 (S9), and the detected pressure Pd and the target pressure Pt are compared (S10). In the case of Pd> Pt, a deceleration process for slightly decelerating the pump rotational speed Nx is executed in S11. In this case, a control signal for adjusting the output frequency of the inverter of the motor drive circuit 36 to be decreased by a predetermined decrease is output to the motor drive circuit 36, and then the process proceeds to S16. If Pd <Pt, a speed increasing process for slightly increasing the pump speed Nx is executed in S12.
[0023]
In this case, a control signal for adjusting the output frequency of the inverter of the motor drive circuit 36 to be increased by a predetermined increment is output to the motor drive circuit 36. Note that in the speed increasing process, since this speed increase by a pump rotational speed Nx is determined whether the pump maximum speed N max or more, in the case of Nx> N max is set to Nx = N max, Control is performed so that the pump rotational speed Nx does not exceed the pump maximum rotational speed Nmax .
[0024]
In S13 subsequent to S12, the motor drive current I calculated based on a predetermined signal from the current detection unit in the motor drive circuit 36 is read, and then it is determined whether or not the motor drive current I is equal to or greater than the rated current Ic. (S14) If I ≧ Ic, the process proceeds to S16. If I ≧ Ic, the current pump speed Nx is given to the target maximum speed value Nm and stored in the memory of the RAM 34 (S15). The process proceeds to S16. If Pd = Pt is determined as a result of the determination in S10, the process proceeds to S16.
[0025]
In S16, it is determined whether or not the pressure set value Ps has been changed from the time of the previous calculation process of S16 to the time of the current calculation process of S16. If there is no change, the process proceeds to S19. However, when the pressure set value Ps is changed, similarly to S2, the pump speed Nc at which the operating current value I becomes the rated current value Ic at the discharge flow rate zero is set as the maximum speed value Nm. Next, the pressure set value Ps is read (S18), and the process proceeds to S19.
[0026]
In S19, the pressure set value Ps and the output frequency of the inverter (which is proportional to the pump discharge flow rate) are applied to a predetermined map or calculation formula to determine the end pressure of the water supply system in the building or building. The target pressure Pt to be constant is calculated, and then it is determined in S20 whether or not a predetermined pump stop condition is satisfied. If the pump stop condition is not satisfied, the process returns to S9 and S9 and subsequent steps are repeatedly executed. If the pump stop condition is satisfied, a stop process for stopping the pump 12 is executed (S21), and then the process proceeds to S3, and S3 and subsequent steps are repeatedly executed.
[0027]
As described above, according to this water supply apparatus 1, after the power is turned on or after the pressure setting is changed, the preset operating rotational speed Nc (operable) at which the operating current value I becomes the rated current value Ic at zero discharge flow rate. Since the pump 12 is controlled with the maximum number of revolutions) as the maximum number of revolutions, it is not necessary to set the maximum number of revolutions of the pump 12, so that the operation is simplified.
[0028]
The pump rotational speed Nx when the operating current value I becomes the rated current value Ic during operation of the pump 12 is stored as Nm, and the pump maximum rotational speed Nmax is updated to Nm at the next pump start-up. Therefore, the pump 12 can be operated while the maximum pump speed max is updated so as to match the use condition of the pump 12 and the pressure setting value Ps, and the capacity of the pump 12 can be maximized. . As a result, the specification range (usable allowable range) of the pump 12 can be greatly expanded, the versatility of the water supply device can be enhanced, and the facility economy and the running cost can be reduced.
[0029]
Note that the embodiment can be implemented by partially changing the embodiment. For example, steps S16 to S18 in the flowchart may be executed separately by interrupt processing. The process of setting the pressure set value Ps omitted in the flowchart may be executed as a separate interrupt process.
[0030]
Further, the “preset pump speed Nc at which the operation current value becomes the rated current value when the discharge flow rate is zero” described in claims 1 and 2 is a theoretical maximum speed, but this pump speed Instead of Nc, “a preset pump rotational speed Nc ′ at which the operation current value becomes the rated current value with a predetermined small amount of discharge flow rate close to zero” may be employed. The water supply device 1 may be a water supply device other than a cabinet-type water supply device. In addition, those skilled in the art can implement the invention with various modifications without departing from the spirit of the present invention.
[0031]
【The invention's effect】
According to the water supply device of the first aspect, after the power is turned on or after the pressure setting is changed, the preset operating rotational speed Nc (maximum operable rotational speed) at which the operating current value becomes the rated current value with the discharge flow rate zero is maximized. Since the pump is controlled as the number of revolutions, it is not necessary to set the maximum number of revolutions of the pump.
[0032]
The pump rotational speed Nx when the operating current value becomes the rated current value during the pump operation is stored in the memory, and the pump is controlled by updating the pump maximum rotational speed to Nx at the next pump startup. The pump can be operated while updating the pump maximum rotation speed so as to meet the use conditions (or the pressure set value or the target pressure), and the capacity of the pump can be maximized. And the specification range (usable allowable range) of a pump can be expanded significantly, the versatility of a water supply apparatus can be improved, and reduction of equipment economy and running cost can be aimed at.
[0033]
According to the water supply device control method of the second aspect, since the first step, the second step, and the third step are provided, basically the same effect as the first aspect can be obtained.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a water supply apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram for explaining an outline of automatic pump operation control;
FIG. 3 is a part of a flowchart of pump automatic operation control.
FIG. 4 is the remaining part of the flow chart of automatic pump operation control.
FIG. 5 is an explanatory diagram of a pump specification range and a maximum capacity line of a conventional water supply device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water supply apparatus 12, 13 Pump 14, 15 Pump drive motor 23 Pressure transmitter 24 Pressure tank 30 Control unit 31 Operation panel

Claims (2)

A pump, a pump drive motor, a pressure tank, a pressure detection means for detecting the discharge pressure of the pump, and a pump so that the pump is started or stopped based on the demand of the water supply system and the detected discharge pressure becomes a target pressure value In a water supply apparatus comprising a control means for controlling the discharge pressure by changing the rotation speed,
The control means updates the pump maximum rotational speed Nmax to the pump target maximum rotational speed Nm, controls the pump rotational speed Nx so that the pump maximum rotational speed Nmax does not exceed the pump maximum rotational speed Nmax, and turns on the water supply device. after or after pressure setting change controls the pump speed Nx pump drivable maximum rotational speed Nc the operating current value is set in advance becomes the rated current value in the discharge flow rate zero as the pump target maximum speed value Nm, the pump the pump speed Nx when the operating current value is the rated current during operation is stored in the memory, the next time the pump starts by feed water system requests stored pump target maximum speed value Nm in the memory A water supply apparatus, wherein the pump is controlled by updating to a pump rotation speed Nx. A method for controlling a water supply apparatus comprising a pump , a pump drive motor, a pressure tank, and a control means for controlling the discharge pressure by starting or stopping the pump and changing the number of revolutions of the pump based on a request for a water supply system In
The control means updates the pump maximum rotation speed Nmax to the pump target maximum rotation speed value Nm, and controls the pump rotation speed Nx so that the pump rotation speed Nx does not exceed the pump maximum rotation speed Nmax.
After power-up or after the pressure setting change of the water supply device, the pump speed Nx pump drivable maximum rotational speed Nc the operating current value is set in advance becomes the rated current value in the discharge flow rate zero as the pump target maximum speed value Nm A first step to control;
Thereafter, a second step of storing in the memory the pump rotation speed Nx when the operating current value becomes the rated current value during the pump operation,
Thereafter, the water supply, characterized in that during pump start by the water supply system request with a third step of controlling the pump to update the pump target maximum speed value Nm in pump speed Nx stored in the memory, the Device control method.

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