JP3411128B2 - Variable speed water supply - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called direct-coupling type variable speed water supply system in which a water distribution pipe is directly connected to a terminal water supply system through a pressure pump, and particularly when the amount of water supply is large or small. The present invention relates to a variable speed water supply device of so-called estimated terminal pressure constant control, which constantly keeps the water pressure supplied to the terminal water supply device constant.

[0002]

2. Description of the Related Art FIG. 1 shows a system outline of a direct connection type variable speed water supply system. For example, an inflow pipe 12 is connected to a water distribution pipe 11 which is a main water pipe, and a pressurizing pump 13 is connected to the inflow pipe. A water meter 15 and an inflow side pressure tank 16 are connected to the inflow pipe 12. Pressure pump 13
A discharge pipe 18 connected to the terminal water supply device 17 is connected to the discharge side of the. A discharge side pressure tank 20 and the like are connected to the discharge pipe 18.

An inflow pressure detector 21 is connected to the inflow side of the pressurizing pump 13, detects the pressure on the inflow side of the pressurizing pump 13, and sends a signal to the controller 22. Similarly, a discharge pressure detector 23 is provided on the discharge side of the pressurizing pump 13, and sends a pressure signal on the discharge side to the control unit 22.

The pump 13 is driven at a variable speed by an electric motor 25 (variable speed means) equipped with a frequency / voltage converter (inverter) connected to a three-phase 200V commercial power source. The control unit 22 sends a signal to the variable speed means 25 based on the signals from the inflow pressure detector 21 and the discharge pressure detector 23 to control the rotation speed of the pump 13 to an arbitrary speed.

Japanese Patent Publication No. 6-112165, Japanese Patent Publication No. 5
-418405, Japanese Patent Laid-Open No. 5-118280, etc. disclose a method for controlling the estimated end pressure constant. With the estimated constant end pressure control, in the variable speed water supply system described above, the pressure on the pump discharge side is controlled by adjusting the pump rotation speed, so that the water supply pressure on the end water supply equipment side is always maintained regardless of fluctuations in the flow rate. It is intended to be controlled in a constant manner. That is, when the amount of supplied water is large, the discharge pressure of the pressurizing pump is set to be higher than the pressure required at the end in consideration of the resistance of the pipe line to secure the required supply water pressure at the end. When the water supply is almost stopped and the pump is close to the deadline operation, the discharge pressure of the pressurizing pump is controlled to the minimum pressure required at the terminal to secure the required water supply water pressure at the terminal.

FIG. 4 shows an example of a conventional variable speed water supply apparatus for performing constant estimated end pressure control without using an expensive flow meter.
Shown in. A water feed pump 3, a variable speed electric motor 2 comprising an inverter and a motor for driving the pump 3, and a rotational speed detecting means 5 for detecting the rotational speed of the variable speed electric motor 2 and outputting a signal of the rotational speed Hzx. , A pressure detecting means 9 provided in the discharge pipe 8 of the water supply pump 3 for detecting the discharge water pressure of the discharge pipe 8 and outputting a signal of the discharge water pressure Pd, and a pressure for setting the necessary discharge pressure PA at the maximum amount of water used. Setting means 101
And the pressure setting means 102 for setting the minimum required discharge pressure PB during the shutoff operation, the pump shutoff pressure P0 and the rotational speed Hz.
The data table 103 for setting the above relationship, the target pressure calculation means 6, and the rotation control means 7 are provided.

In the variable speed water supply system having the above structure, the target pressure calculating means 6 determines the target discharge pressure PV corresponding to the rotation speed Hzx as a function (PV = f (Hz) of the rotation speed Hzx.
x)), and the discharge pressure Pd is the target pressure PV in response to the target discharge pressure PV and the actual discharge pressure Pd.
The speed of the variable speed electric motor 2 is controlled so as to coincide with.

However, the variable speed water supply apparatus having the above-described structure is effective in a piping system having a water receiving tank or the like on the inflow side (primary side) of the water supply pump 3 and in which the inflow pressure Ps does not change much. However, in a piping system in which the water supply pump 3 is directly connected and pressurized in the middle of the piping, in other words, in a piping system in which the pressure on the primary side of the pump changes significantly depending on the usage state of water, the pressure on the secondary side of the pump is kept constant. It was difficult to control.

In order to avoid such a problem, Japanese Patent Laid-Open No. 5-1
According to the invention disclosed in Japanese Patent No. 18280, a water supply book
By detecting the inflow water pressure from the pressure sensor provided on the pump primary side (inflow side) where the water in the pipe flows, and by correcting the control calculation formula one by one with this detected value, the pump primary side pressure can be changed depending on the water usage condition. There is disclosed a variable speed water supply device capable of controlling the pressure on the secondary side of the pump to be constant at the end pressure even if it changes.

As shown in FIG. 5, a variable speed electric motor 2 which is connected to the water supply pump 3 and drives the pump 3, and a rotational speed detecting means 5 for detecting the rotational speed Hzx of the variable speed electric motor 2.
A discharge pressure detecting means 9 for detecting the discharge pressure Pd of the water supply pump 3, a pressure setting means 101 for setting a set pressure PA at the maximum amount of water used, and a pressure setting means 102 for setting a set pressure PB at the deadline operation. And a data table 103 for setting the relationship between the pump cutoff pressure P0 and the rotation speed Hz. Then, the target pressure PV corresponding to the rotation speed Hzx is a function (PV = f (Hz) of the rotation speed signal Hzx.
x)) in response to the target pressure calculating means 6 and the target pressure signal PV and the discharge pressure Pd so that the discharge pressure Pd matches the target pressure signal PV.
And a rotation speed control means 7 for controlling the speed. A pressure control means 9X provided on the inflow side of the water supply pump 3 for detecting the water pressure Ps on the inflow side is provided, and the target pressure PV calculation function (PV = f (Hzx)) of the target pressure calculation means 6 is set to the inflow water pressure P.
It is characterized in that the target pressure PV is calculated by the function (PV = f '(Hzx)) obtained by changing it by s.

[0011]

The pressure in the "data table storing the relationship between the pressure during pump shutoff operation and the pump rotation speed" used for constant estimated end pressure control is at the actual pump head, that is, when the inlet pressure is zero. Must be the discharge pressure of the pump. When there was a conventional water receiving tank, the pressure on the inflow side was zero, and the discharge pressure of the pump was the characteristic of the pump as it was. Therefore, the correct data table could be created in the setting operation mode after installation and adjustment on site. However, since it is directly connected and pressure is applied to the inflow side of the pump, the characteristic that the inflow pressure is added to the characteristic of the pump is taken in in the conventional setting operation mode during field installation,
The function derived using the coefficient obtained by searching the data table is incorrect. Therefore, the estimated constant end pressure cannot be controlled correctly. In addition, there was a problem that the setting operation could not be performed at the site by setting the pressure on the inflow side to zero.

The present invention has been made in view of the above-mentioned circumstances, and in the direct-coupling type variable speed water supply apparatus, the setting at the time of on-site installation of the pump is easy, and the estimated end is stable even if the inflow pressure fluctuates. An object of the present invention is to provide a variable speed water supply device capable of performing a constant pressure control operation.

[0013]

The variable speed water supply system of the present invention comprises an inflow pressure detector connected to the mains of water supply and outputting an inflow pressure signal Ps representing the water pressure on the inflow side of the pump , and a pressurizing pump. , A discharge pipe connected to the discharge side of this pressure pump,
A discharge pressure detector that outputs a discharge pressure signal Pd representing the water pressure on the discharge side of the pump, a motor that is connected to the pump and drives the pump, and variable speed means that shifts the motor are provided .
A variable speed water supply device for performing constant constant end pressure control, the water supply device comprising the discharge pressure signal Pd and the inflow pressure signal Ps.
A differential pressure detecting means for calculating a differential pressure delta P of, writing the rotation speed Hz is raised at a predetermined interval the differential pressure ΔP at the pump discharge operation corresponding to the rotational speed of the pump to de Tateburu Means and an automatic setting operation mode capable of automatically rewriting the data table to the data of the installation site at the time of installation and adjustment of the water supply device at the installation site.

[0014]

According to the present invention, the differential pressure ΔP between the discharge side pressure Pd and the inflow side pressure Ps at each rotational speed is set to the differential pressure between the inflow pressure detector and the discharge pressure detector in the set operation mode during field installation. Since the data table is created by taking in as, it is possible to create a correct data table even if pressure is applied to the inflow side. Since the data table automatic creation function is provided, the data table can be easily created even if pressure is applied to the inflow side during installation and adjustment at the site. Therefore, by creating a data table in the automatic setting mode after the installation and adjustment at the site, the estimated end pressure constant control can be immediately performed using correct data.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

Also in this embodiment, the system configuration in which the pressurizing pump 13 is directly connected to the water distribution pipe 11 and the terminal water supply device 17 is directly connected to the water distribution pipe 11 without using the water tank is as shown in FIG. Then, the pressurizing pump 13 controls the discharge pressure by the variable speed means 25 such as an inverter so as to increase or decrease the pump rotation speed so that the water supply pressure to the terminal water supply device 17 becomes constant by the signal of the discharge pressure detector 23. . Further, when the inflow pressure decreases, the variable speed means 25 reduces or stops the pump rotation speed so that the water distribution pipe is not adversely affected and the inflow pressure does not drop below a certain inflow set pressure. Control is performed. Then, the discharge pressure control is switched to the inflow pressure control when the inflow pressure Ps becomes equal to or lower than the selected set pressure.

FIG. 2 shows a configuration related to the control of the estimated end pressure constant of the control portion 22 of the variable speed water supply system according to the embodiment of the present invention. The pressure Ps on the inflow side of the pressure pump 13 is input from the inflow pressure detector 21, and the pressure Pd on the discharge side of the pressure pump 13 is input from the discharge pressure detector 23. The control target pressure of the terminal water supply device is usually set to 1 to ² kg / cm ² . The discharge pressure PA at the maximum water amount set by the pressure setting means 1 is the discharge pressure set in consideration of the loss due to the line resistance when the maximum water amount is supplied to the terminal water supply device, and is usually the rated rotation speed of the pump. (50H in East Japan
z, 60 Hz in western Japan) is the discharge pressure at the maximum flow rate assumed. The discharge pressure PB set by the pressure setting means 2 during the shutoff operation has almost no loss due to the line resistance in the shutoff state where there is almost no water supply. Become.

In this embodiment, when the set discharge pressure PA at the maximum flow rate and the set discharge pressure PB at the dead cut operation are given, the target discharge pressure PV 'corresponding to the rotational speed Hzx of the pump can be calculated. . The calculation of the target discharge pressure PV 'is performed by the target pressure calculation means 6, and is performed by referring to the data table 103 that stores the relationship between the rotational speed Hz of the pump and the shutoff pressure P. When the target discharge pressure PV 'is obtained, the actual discharge pressure P is calculated by the rotation speed control means 7.
It is compared with d, and a command to increase or decrease the speed is issued to the variable speed means 25 so that the pressure PV 'matches the pressure Pd. The rotation speed detection means 5 calculates the rotation speed Hzx of the pump from the PWM signal of the inverter of the variable speed means 25.

In this embodiment, the differential pressure detecting means for calculating the differential pressure ΔP between the discharge pressure Pd and the inflow pressure Ps, the rotational speed setting means for gradually increasing the rotational speed of the pump at a predetermined interval, and the difference between the rotational speed and the rotational speed. An automatic setting operation mode 104 including a writing unit for writing the pressure relationship in the storage unit is provided.

FIG. 3 shows the flow of the automatic setting operation mode. After installing the pump at the installation site, create a data table of the differential pressure ΔP and the rotation speed Hz. In this flow, first, the rotational speed Hz of the pump is set to zero and, for example, 0.2
Gradually increase at a predetermined interval of 5 Hz. Then, the inflow pressure Ps and the discharge pressure Pd at the rotational speed Hz are read, and the differential pressure ΔP is obtained by the differential pressure detecting means and NVRA.
The data is written in the storage unit (data table 103) configured by M or the like. This operation is repeated until the rotation speed reaches the rated speed.

The procedure for calculating the target pressure is as follows. First, the target discharge pressure PV for an arbitrary rotation speed Hzx
When the inflow pressure is zero, Eq.

[Equation 1] However, PA: Set discharge pressure at rated operation (maximum flow rate) (inflow pressure is zero) PB: Set discharge pressure at deadline operation (minimum flow rate) (inflow pressure is zero) HzO: Rotation speed at rated operation HzB: Deadline operation Sometimes corresponding rotational speed (zero inflow pressure)

By the way, the data table 103 stores data on the relation of the shutoff pressure P with respect to an arbitrary rotation speed Hz. This is, for example, 0 Hz in East Japan
To 50 Hz, for example, at intervals of 0.25 Hz, the shutoff pressures corresponding to these rotation speeds are stored in a storage device such as NVRAM. In the formula (1), it is premised that the shutoff pressure is zero inflow pressure. In this embodiment, the differential pressure ΔP between the discharge pressure Pd and the inflow pressure Ps corresponding to each rotation speed is taken in during the installation adjustment at the installation site. This pressure difference ΔP corresponds to the dead pressure when the inflow pressure is zero. That is, according to the automatic setting operation mode 104, the data table created after the pump is installed at the installation site becomes the dead pressure when the required inflow pressure is zero. Then, from the given target discharge pressure PB at the deadline, the rotational speed HzB when the inflow pressure is zero is given from the data table.

When the inflow pressure Ps exists, the target discharge pressure PV 'corresponding to the arbitrary rotation speed Hzx is (2)
The correction calculation shown in equations (3) and (4) is performed.

[0024]

[Equation 2]

Therefore, the corrected target pressure PV 'output from the target pressure calculation means 6 and the actual discharge pressure Pd are compared by the rotation speed control means 7. As a result of the comparison, the rotation speed is increased or decreased so that the discharge pressure approaches the target pressure, and the discharge pressure is adjusted to the target pressure that keeps the end pressure constant.

The above-mentioned data table 103 is a table that stores measured data of the rotational speed Hz and the differential pressure ΔP of the shutoff pressure, but it is not necessarily a table and a function may be used. Of course.

The target pressure calculating means for constant control of the estimated end pressure is merely an example, and it is needless to say that various modified calculating expressions can be used.

[0028]

As described above, according to the present invention,
In a variable speed water supply system with a constant end pressure control system, the discharge pressure P is stored in the data table of the relationship between the rotational speed of the pump and the dead pressure.
The differential pressure ΔP between d and the inflow pressure Ps is taken in in the automatic setting operation mode. Therefore, after installing the pump,
It is possible to create the correct data table necessary for calculating the target discharge pressure in the automatic setting operation mode. Therefore, in the variable speed water supply apparatus, the constant end pressure control can be easily and accurately performed at the installation site.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a system configuration of a direct connection type variable speed water supply device.

FIG. 2 is an explanatory diagram of a control system according to an embodiment of the present invention.

FIG. 3 is a flowchart of an automatic setting operation mode.

FIG. 4 is an explanatory diagram of a conventional system configuration for constant end pressure control.

FIG. 5 is an explanatory diagram of a conventional system configuration for constant end pressure control.

[Explanation of symbols]

5 Rotational speed detection means 6 Target pressure calculation means 7 Rotation speed control means 3,13 pump 21,23 Pressure detector 25 Variable speed means 101 Pressure (PA) setting means 102 Pressure (PB) setting means 103 data table 104 Automatic setting operation mode Ps Inflow side pressure Pd Discharge side pressure

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) F04D 15/00 F04B 49/00-49/10

Claims (2)

(57) [Claims] Claims: 1. An inflow pressure detector connected to a mains of water supply, which outputs an inflow pressure signal Ps representing a water pressure on the pump inflow side , a pressurizing pump, and a discharge side of the pressurizing pump. Discharge pressure signal Pd representing the water pressure on the discharge side of the connected discharge pipe and pump
A discharge pressure detector which outputs a, a motor for coupling to drive it to the pump, a variable speed means for shifting the motor
And a variable speed water supply device for performing a constant estimated end pressure control , wherein the water supply device includes the discharge pressure signal Pd and the inflow pressure signal P.
a differential pressure detecting means for calculating a differential pressure delta P of s, writing the rotation speed Hz is raised at a predetermined interval the differential pressure ΔP at the pump discharge operation corresponding to the rotational speed of the pump to de Tateburu means for writing, when adjusting installation at the installation site of the water supply device, variable speed, characterized in that an automatic setting operation mode can be automatically rewriting the data table to the installation site <br/> data water apparatus. 2. The water supply device is required for the maximum amount of water used.
Pressure setting means to set discharge pressure PA and
Pressure setting means for setting the required minimum discharge pressure PB, The rotation speed signal Hzx and the inflow pressure signal Ps are used for pairing.
Search the data table for the corresponding target pressure PV '.
Calculated by a function derived using the coefficient obtained by
Target pressure that outputs the target pressure signal PV 'that represents the target pressure
Computing means, Responsive to the target pressure signal PV 'and the discharge pressure signal Pd
Then, the discharge pressure signal is compared with the target pressure signal PV '.
The variable speed is adjusted so that the pressures represented by Pd match.
Rotation speed that outputs speed signal to the means and controls the speed of the pump
The control device according to claim 1, further comprising a control means.
Variable speed water supply device.