JPH0612116B2 - Variable speed water supply device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for adjusting the amount of water in a water supply facility.

“Prior Art” In water supply equipment, there is a demand from the user side at the end of piping to obtain the required pressure and flow rate, and it is necessary to maintain the required pressure although the used flow rate fluctuates. The fluctuation of the amount of water used has been dealt with by changing the rotational speed of the turbo pump driven by the variable speed motor. In such a case, control such as constant discharge pressure or constant estimated end pressure is conventionally performed.

FIG. 5 shows an example of constant pressure control, in which the horizontal axis represents the flow rate and the vertical axis represents the pressure. 111 is a pump performance curve. In this case, the discharge pressure P of the pump is controlled by controlling the rotational speed so that the discharge pressure of the pump becomes a constant pressure at a pressure obtained by adding the pressure loss P _c of the pipeline at the maximum flow rate to the required pressure P _n at the end of the pipe. ing. However, according to this method, the pipe end required pressure P _n fluctuates greatly due to the resistance of the pipe that changes in proportion to the square of the flow rate, and it is considered that energy loss occurs in the range indicated by the diagonal lines in the figure.

In the conventional control method shown in FIG. 6, which is shown in the same coordinates as in FIG. 5, the pump discharge pressure P is determined in consideration of the pressure loss in the pipeline so that the estimated end pressure becomes constant. The pump discharge pressure is changed according to the change corresponding to the flow rate of the pressure loss P _c of the pipeline, that is, the resistance curve. In Fig. 6, in a water supply system using a pump, the required pressure and flow rate at the end of the pipe are equipped with a flow meter, and the pressure loss in the pipe corresponding to the flow meter is taken into account Is added to the pump discharge pressure.

Such a method is expensive because it requires a flow meter.
In this case, the piping is different and the pump characteristics are also different.Therefore, it has to be applied to each individual pump device. Not suitable.

In addition to the above, there is also a method of storing and controlling the performance of the pump, but it requires time and labor to collect data, and can be applied only to individual systems. For example, Japanese Patent Application Sho 57
The invention of -162326 (Japanese Patent Laid-Open No. 59-51193) inputs "a function of a load resistance curve of a diameter of a line connecting pumps" and "a function of a QH performance curve of a pump at an arbitrary rotation speed" to a storage device. However, as a procedure therefor, it requires a lot of labor in practice, and it is difficult for a general user to calculate technically. In addition, "the value detected by the load state detection device () is substituted into the function of the QH performance curve to obtain the current operating point of the pump, and the operating point is substituted into the function of the load resistance curve. It is a very complicated process to calculate the target pressure so that both operating points are equal.

The present invention makes it easier to set the required terminal pressure to be substantially constant by controlling the control target pressure that changes with the change of the rotation speed in the pump device, and to estimate the estimated terminal pressure. An object of the present invention is to provide a pump device that facilitates a target pressure calculation formula for performing constant control.

"Means for Solving the Problems" The present invention relates to a pump, a water supply pipe connected to the discharge side of the pump, and a pressure signal S connected to the water supply pipe and representing the water pressure.
1, a pressure detecting means for outputting 1, a motor connected to and driving the pump, a variable speed means for changing the speed of the motor, a rotational speed of the pump is detected, and a rotational speed signal S3 representing the rotational speed is output. Rotation speed detecting means, pressure setting means 1 for setting the required pressure PA at the maximum amount of water used, pressure setting means 2 for setting the minimum required pressure PB at the deadline, and pump rotation speed during the pump deadline operation and its pump rotation. The table of data stored in the storage device by shutting down the pump in the set operation mode in which the relationship between the pump discharge pressure and the pump speed is manually input, or the discharge pressure is automatically input when the pump rotation speed is increased The target pressure S corresponding to the rotation speed represented by the speed signal S3
V is a pump rotation using a coefficient obtained by a calculation using the pump rotation speed obtained by searching the data table, the set required pressure PA at the maximum usable water amount and the set minimum required pressure PB at the deadline. The target pressure SV is calculated in accordance with the relational expression between the speed and the target pressure, and outputs the target pressure SV representing the target pressure, and the target pressure SV in response to the target pressure signal SV signal and the pressure signal S1. In contrast, the variable speed water supply device is provided with rotation speed control means for outputting the speed signal S2 to the variable speed means and controlling the speed of the pump so that the pressures represented by the pressure signal S1 match.

[Operation] This device is a pump (1), a water supply pipe (2) connected to the discharge side of this pump, and a pressure detection device that is connected to this water supply pipe (2) and outputs a pressure signal S1 representing the water pressure. Means (3) For example a pressure sensor and a motor (4) connected to and driving the pump
And a variable speed means (5) for shifting the motor, for example, an inverter, and a speed detection means (6) for detecting the rotation speed of the pump and outputting a rotation speed signal S3 representing the rotation speed, for example, a speed command to the inverter. And a signal to control the speed of the pump. As a setting device for speed control, for example, by using a digital switch or the like, the required pressure P at the maximum amount of water used
The pressure setting means 1 (7) for setting A and the pressure setting means 2 (8) for setting the required pressure PB at the deadline are provided.

In addition, the pressure and the pump rotation speed during the pump cutoff operation obtained by manually inputting or operating the pump shutoff according to the set operation mode and automatically inputting the discharge pressure value S3 from the pressure sensor while gradually increasing the rotation speed. It has a data table (9) that stores the relationship of

Generally, a pump user who intends to introduce a pump into a facility has a purpose of preventing a pressure shortage and a water amount shortage on the water receiver side. Therefore, when planning the pump equipment, the required pressure and the required water volume are planned. This is called a pump guideline and is used as the basis for selecting pump equipment.

In this plan, the pump user determines the total head from the head loss, the actual head and the minimum required pressure of the water supply equipment.

In the present invention, the pressure corresponding to the total head is set by the pressure setting means 1 (7) which sets the required pressure PA at the maximum used water amount as the required pressure PA at the maximum used water amount. Required pressure at deadline P equivalent to
B is set by the pressure setting means 2 (8) for setting the required pressure PB at the deadline.

Further, the present apparatus is provided with a target pressure calculating means for outputting the target pressure SV corresponding to the rotation speed represented by the rotation speed signal S3. In this target pressure calculation means, the pump rotation speed obtained by searching the data table (9), for example, the pump rotation speed HzB at the deadline at the set pressure PB and the maximum rotation speed HzO (this is the required pressure determined when the maximum amount of water is used). It is a value determined when a pump is selected based on PA, and usually becomes the pump rated rotation speed (maximum rotation speed)) and a coefficient obtained by calculation using the set pressure set values PA and PB ( For example, coefficient K1
= (PA-PB) / (HzO-HzB))
The target pressure SV is controlled so that the approximate target pressure becomes constant at the terminal pressure by a relational expression (for example, SV = SV = K1 * (S3-HzB) + PB) between the rotational speed S3 and the target pressure SV. To calculate.

The variable speed means (5) is responsive to the target pressure signal SV and the pressure signal S1 so that the pressure represented by the pressure signal S1 matches the target pressure SV.
Since there is a rotation speed control means (11) (for example, PID control, fuzzy control, etc.) that outputs a speed signal S2 to the pump to control the speed of the pump, the pump is sequentially controlled to an appropriate target pressure, and the pump end pressure is kept substantially constant. You can control it.

"Example" FIG. 1 is a flow sheet showing a pump device. Water is drawn from a water source 13 through a suction pipe 14 to a pump 1 driven by a motor 4 that controls the rotation speed by changing the frequency, and the water is pressurized and discharged to a water supply pipe 2. The pressure in the water supply pipe 2 is detected by a pressure detecting device 3 provided as a pressure detecting means, and is sent to the demand side by a discharge pipe 19 via a check valve 17 and a sluice valve 18.

The pressure signal S1 of the pump 1 detected by the pressure detector 3 is sent to the rotation speed control means 11 in the control unit 21. In the rotation speed control means 11, a speed signal S2 is output from the signal of the target pressure SV from the target pressure calculation means 10 and the pressure signal S1 from the pressure detection hand device 3 by proportional-plus-integral control or the like, and a variable speed means for changing the speed of the motor. 5 is input to the inverter or the like, and the inverter outputs the required frequency and sends it to the motor 4 to operate the motor at the required speed. The frequency generated by the inverter and sent to the motor 4 is sent to the target pressure calculation means 10 via the rotation speed detection means 6 which outputs the rotation speed signal S3.

The control unit 21 uses a micro computer,
It is provided with a pressure setting means 1 (7) for setting the required pressure PA when the maximum amount of water is used, such as a digital setting device, and a pressure setting means 2 (8) for setting the required minimum pressure PB at the deadline. A data table 9 storing the relationship between the pump rotation speed during the pump shutoff operation and the pump discharge pressure at the pump rotation speed is stored in the storage device of the microcomputer of the control unit 21.
Have This data table may be entered in advance, but in the field, if the sluice valve 18 of the pump water supply pipe 2 is closed, the set operation mode in which the pump rotation speed is increased and the discharge pressure is automatically input to the control unit 21 is set. By providing the data, the pump can be shut off and input to the storage device to easily obtain data.

The target pressure calculation means 10 in the control unit 21 calculates the target pressure SV to be input to the rotation speed control means 11 using these setting data.

The specific calculation method is (1) HzB = F (PB) where; HzB; Pressure setting means 2 for setting the minimum pressure required at the deadline.
Rotational speed for generating the minimum required pressure PB at the deadline set by (8) (obtained from the data table 9) F (); Pump rotational speed during pump deadline operation in the target pressure calculation means 10 and its rotational speed A program for retrieving the pump rotation speed coefficient from the data table 9 that stores the relationship of the pump discharge pressure at K1 = (PA-PB) / (HzO-HzB) where: HzO; set maximum rotation speed (normal commercial power supply frequency 50
Hz or 60 Hz, which is the rotation speed of the motor 4, but can be arbitrarily determined by setting) PA: Required pressure PA at maximum water consumption (pressure setting means 1)
User inputs using (7)) PB; minimum required pressure at deadline PB (pressure setting means 2)
It is entered by the user using (8). ) The rotation speed signal S is calculated by the coefficient K1 derived by
The target pressure SV when 3 is entered is S3 <HzB SV = PB ... (1) HzB = <S3 <HzO SV = K1 * (S3-HzB) + PB ... (2) HzO <S3 SV = PA (4) That is, (1) of the specific calculation method described above is derived when ALP = 1 and BET = 1 in the formula in (2) of the following specific calculation method. ALP = 1 By PM = PA HzPM = F (PA), then by HzPM = HzA BET = 1, by HzM = DHz + HzPM, by HzM = HzO From above, K1 = (PA-PB) / (HzO-HzB) K2 = 0 (2) HzB = F (PB) HzA = F (PA) DHz = HzO-HzA DP = PA-PB PM = DP * ALP + PB HzPM = F (PM) HzM = DHz * BET + HzPM K1 = (PM-PB) / (HzM-HzB K2 = (PA-PM) / (HzO-HzM) where; HZO; set maximum rotational speed (usually 50Hz or 60H
z) PA: Required pressure PA at maximum water consumption (pressure setting means 1)
(7)) PB; minimum pressure required at deadline PB (pressure setting means 2
(8)) ALP, BET; a constant of 0 or more and 1 or less (set or fixed, for example, ALP = BET = 0.5) F (); Pump rotation speed during pump shutoff operation in the target pressure calculation means 10 and its pump A program for retrieving the pump rotation speed coefficient from the data table 9 that stores the relationship between the pump discharge pressure and the rotation speed. The other coefficients are obtained by the above calculation.

The target pressure SV when the rotation speed signal S3 is input by the coefficients K1 and K2 derived by the following equation is S3 <HzB SV = PB ... (1) HzB = <S3 <HzM SV = K1 * (S3- HzB) + PB ... (2) HzM = <S3 = <HzOSV = K2 * (S3-HzM) + PM ... (3) HzO <S3 SV = PA ... (4) I'm running.

FIG. 2 is a flow chart showing the operation.

The pressure detecting device 3 changes as the flow rate used changes.
That is, the value of the pressure signal S1 indicated by the pressure detector 3 decreases as the used flow rate increases and decreases. The pressure signal S1 indicated by the pressure detector 3 is sent to the controller 21.

In the control unit 21, the speed signal S2 sent to the inverter 5 is sent to the routine 100, and in the routine 100, as described above, in the routine 100, pump pressure-pump rotation speed (frequency characteristic), frequency at maximum flow rate, setting time. The target pressure SV is calculated using the shutoff required pressure PB, the required pressure PA at the maximum flow rate used, and the like. The target pressure SV thus obtained is determined in routine 101 from the difference between the pressure signal S1 and the target pressure SV, the changing speed of the difference, etc., and the speed signal S2 is obtained so that the pump discharge pressure P approaches the target pressure SV (PI Calculation), and output to the variable speed means 5, that is, the inverter. Control unit 21
When the target pressure SV is larger than the pressure value indicated by the pressure detecting device 3, the motor 4 is accelerated through the inverter. When the target pressure SV is smaller than this pressure value, the motor 4 is transmitted through the inverter. Slow down. In this way, the motor 4 is shifted through the inverter so that the pressure indicated by the pressure detecting device 3 is controlled to be the target pressure SV obtained above, and the rotation speed of the motor 4 and the pump 1 and the pressure detector 3 are controlled. The detected pressure of changes correspondingly.

FIG. 3 is a block diagram showing the control device. The signal S1 of the pressure detection hand device 3 and the speed signal S2 of the inverter are input to the microcomputer through the interface 24,
Data table 9 of these values and the above-mentioned pressure when the pump is shut off and stored in the storage device 26: pump rotation speed
The target pressure SV is calculated by the central processing unit 25 using
The frequency is calculated so as to be output to the inverter 5 via the interface 24, and the inverter 5 controls the rotation speed of the motor 4 to operate the pump 1 so that the target pressure SV is reached.

The above data table is shown in Table 1.

F () is a data retrieval program included in the target pressure calculation means. As shown in Table 1, when the program is started with an arbitrary cutoff pressure as an argument, the program is such that the rotational speed of the pump at that cutoff pressure is retrieved from the data table and returned. Has been done.

For example, the pump cutoff pressure P is 28 (m) by searching.
In order to determine the pump rotation speed Hz in this case, F (28) = 46 Hz as shown in the margin of Table 1.

An example is shown in FIG. In FIG. 4, the pressure at the maximum flow rate used is 4 kg / cm ^{2 and the} minimum pressure required when the pump is shut off is PB = 2 kg / cm ² , and the horizontal axis shows the flow rate Q and the vertical axis shows the pressure P. The control target pressure calculated with ALP = 0.5 and BET = 0.6 is shown in the curve 23, and the end pressure P _n = P
B is almost constant.

〔The invention's effect〕

As described above, according to the present invention, the pump, the water supply pipe connected to the discharge side of the pump, the pressure detection means connected to the water supply pipe for outputting the pressure signal S1 representing the water pressure, and the pump connected thereto A motor to be driven, a variable speed means for changing the speed of the motor, a rotation speed detecting means for detecting the rotation speed of the pump and outputting a rotation speed signal S3 representing the rotation speed, and a required pressure PA at the time of maximum water usage are set. Pressure setting means 1, a pressure setting means 2 for setting a minimum required pressure PB at the deadline, and a pump rotation speed during the pump deadline operation, and manually input the relationship between the pump discharge pressure at the pump rotation speed, or the pump rotation. A table of data stored in the storage device and a data table in which the pump is shut off in a set operation mode in which the discharge pressure is automatically input when the speed is increased, and the rotation speed signal S3. The target pressure SV corresponding to the rotation speed that is, the set and the pump rotational speed obtained by searching the data table has been used up to the amount of water when necessary pressure P
A target pressure signal S representing the target pressure is calculated by a relational expression between the pump rotation speed and the target pressure using the coefficient obtained by the calculation using A and the minimum required pressure PB at the deadline.
A target pressure calculating means for outputting V, and the target pressure SV in response to the signal of the target pressure SV and the pressure signal S1.
In contrast, the variable speed water supply device is provided with the rotation speed control means for outputting the speed signal S2 to the variable speed means and controlling the speed of the pump so that the pressures represented by the pressure signal S1 match. There is no energy loss to control with constant pump discharge pressure, and a variable speed water supply system that does not require a flow meter to control the discharge pressure at the end of the pipe is actually measured and controlled for each water supply facility. The pipe end pressure can be kept almost constant without the labor and time-consuming method of performing.

That is, the pump user is interested in what pressure is required at the time of installing the pump, but is not interested in what the pump rotation speed is at that time, and technical knowledge for obtaining that rotation speed. Nor. In the conventional device, it is difficult to generalize because it is necessary to adjust the rotation speed and other complicated settings for each product. In the present invention, since there is the data table (9) and the unique target pressure calculation using the data table (9), complicated knowledge of the pump rotation speed is not required.

As a method of determining the control target pressure based on the pump rotation speed, a data table that stores the pressure value at each rotation speed when the pump is fully closed and the rotation speed and pressure value data when the required pressure at the maximum water volume used is being output Since the control device for obtaining the control target pressure for each rotational speed is provided, the pump rotational speed-discharging pressure characteristic when the pump is shut off can be easily obtained, and is suitable for a water supply device that is mass-produced. The rotation speed when the required pressure is being generated at the maximum water usage can be obtained by calculating the pressure loss in the pipeline, and can also be easily obtained by actual measurement. Target pressure S at each pump speed
Since V can be obtained and controlled, the control is extremely simple. Such a target pressure SV can be obtained by appropriately setting a constant when using the expressions (1) to (4), for example.

[Brief description of drawings]

The drawings show examples, FIG. 1 is a flow sheet of a water supply facility used in the present invention, FIG. 2 is a flow chart of the present invention, FIG. 3 is a block diagram of the present invention, and FIG. 4 is an experiment of the present invention. An example diagram, FIG. 5 and FIG. 6 are diagrams showing a conventional control method. 1 ... Pump, 3 ... Pressure detector, 4 ... Motor, 5
...... Inverter, 6 ...... Rotation speed detection means, 7 ...... Pressure setting means 1, 8 ...... Pressure setting means 2, 9 ...... Data table of pump cutoff pressure and pump rotation speed 11 ...... Rotation speed control means, 18 ... Gate valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hironao Hiraiwa 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Ebara Corporation (72) Inventor Takuo Akahori 1-3-1 Ginza, Chuo-ku, Tokyo Stocks Company Ebara Densan (72) Inventor Shinji Aoto 1-3-1 Ginza, Chuo-ku, Tokyo Stock company Ebara Densan (56) Reference JP 57-35180 (JP, A) JP Sho 57-113992 (JP, A) JP-A-52-78103 (JP, A) JP-A-56-110589 (JP, A) JP-A-59-51193 (JP, A) Actual development Sho-53-53601 (JP, A) U) Japanese Patent Sho 46-1225 (JP, B1) Japanese Patent Sho 43-18282 (JP, B1)

Claims (2)

[Claims] 1. A pump (1), a water supply pipe (2) connected to the discharge side of the pump, and pressure detection means (1) connected to the water supply pipe (2) for outputting a pressure signal S1 representing the water pressure. 3), a motor (4) connected to and driving the pump, a variable speed means (5) for changing the speed of the motor, a rotational speed of the pump is detected, and a rotational speed signal S3 representing the rotational speed is output. Rotation speed detection means (6), pressure setting means 1 (7) for setting the required pressure PA at the maximum amount of water used, pressure setting means 2 (8) for setting the minimum required pressure PB at the deadline, and pump shutoff operation Storage device by manually inputting the relationship between the pump rotation speed at that time and the pump discharge pressure at that pump rotation speed, or by shutting down the pump in the set operation mode in which the discharge pressure is automatically input when the pump rotation speed is increased. The data table (9) stored in The target pressure SV corresponding to the rotation speed represented by the signal S3 is set to the pump rotation speed obtained by searching the data table (9) and the set required pressure PA at the maximum usable water amount and the required minimum pressure PB at the deadline. A target pressure calculation means (10) for calculating a target pressure signal SV representing the target pressure, which is calculated by a relational expression between the pump rotation speed and the target pressure using the coefficient obtained by the calculation, and the target pressure SV. In response to the signal and the pressure signal S1, the speed signal S2 is output to the variable speed means (5) so that the pressure represented by the pressure signal S1 matches the target pressure SV, and the pump speed is increased. A variable speed water supply device provided with a rotation speed control means (11) for controlling. 2. The target pressure calculation means (10) uses a data table (9) which stores the relationship between the pump rotation speed when F () is shut off and the pump discharge pressure at the pump rotation speed. HzB = F (PB) as a program for retrieving the coefficient, however; HzB; minimum pressure required at deadline set by pressure setting means 2 (8) for setting minimum pressure required at deadline PB obtained from the data table (9) The rotation speed for generating PB is obtained, and using this HzB, K1 = (PA-PB) / (HzO-HzB) HzO; set maximum rotation speed (usually 50 Hz or 60 H
z) PA: Required pressure PA at maximum water consumption (pressure setting means 1)
(7)) PB; minimum pressure required at deadline PB (pressure setting means 2
(8)) The rotation speed signal S is calculated by the coefficient K1 derived by
The target pressure SV when 3 is entered is sequentially calculated by S3 <HzB SV = PB HzB = <S3 <HzO SV = K1 * (S3-HzB) + PB HzO <S3 SV = PA. Range 1st
Variable speed water supply device according to the item.