JP2000283553A - Water circulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make hard to receive the affection of a variety in the efficiencies of each pumps, a temperature change, noises as well as the current consumption of a controlling circuit and permit the accurate detection of an output flow rate generated by the pumps. SOLUTION: A water circulating device is provided with a pump 1, circulating water in a water tank, a motor 2, a driver 3 for changing the rotating number of the motor 2 in proportional to the duty ratio of a pulse, a pulse width modulating circuit 5 for regulating the duty ratio of the pulse to obtain a predetermined number of rotation of the motor 2, a measuring means 6 for measuring the duty ratio of the pulse, a memory 7 into which a characteristic parameter 8 including a relation between the duty ratio and the flow rate is written, and a microcomputer 9 for detecting the flow rate from the characteristic parameter 8 of the memory 7 and the duty ratio. In such a water circulating device, the output flow rate of the pump is detected with a high accuracy from the measured duty ratio by the characteristic parameter 8 indicating the relation between the duty ratio and the flow rate, which is previously written into the memory 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulating device for bath water or hot water, and more particularly to a method for accurately detecting a change in an output flow rate due to an abnormality in the device or clogging of piping.

[0002]

2. Description of the Related Art A known method for detecting the output flow rate of a pump is to read the current consumption of a motor connected to the pump and detect the flow rate generated from a relational expression between the current and the flow rate which is obtained in advance. Have been.

[0003]

However, in a conventional water circulating device for detecting the output flow rate of a pump, even if the same output flow rate is generated, the current consumption varies due to variations in the efficiency of the pumps, and a pump is generated. However, there is a problem that the output cannot be detected with high accuracy, a circuit for reading the current is easily affected by a temperature change or noise, and a current consumption of a motor control circuit is also easily affected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the effects of variations in efficiency of each pump, temperature changes, noise, and current consumption of a control circuit. It is an object of the present invention to provide a water circulating device that can accurately detect an output flow rate at which water is generated.

[0005]

To achieve the above object, the present invention provides a pump for circulating water in a water tank, a motor for driving the pump, and a motor for rotating the motor in proportion to the duty ratio of the pulse. A driver for changing, a pulse width modulation circuit for reading a signal proportional to the number of rotations of the motor and adjusting a duty ratio of a pulse so as to bring the motor to a predetermined number of rotations, a means for measuring a duty ratio of the pulse, and a duty ratio A memory in which characteristic parameters containing the relationship between the flow rate and the flow rate are written, and a microcomputer that detects the flow rate from the characteristic parameters of the memory and the current duty ratio, before the operation of the pump, the characteristics of the relationship between the duty ratio and the flow rate Write the parameters to memory in advance,
During operation, the characteristic parameters are read from the memory,
It has means for detecting the output flow rate of the pump from the measured duty ratio. In the water circulation device of the present invention, when the output flow rate of the pump is small, the load is small, so the duty ratio is small. When the output flow rate is large, the load is large, so the duty ratio is large. It has the function of adjusting the duty ratio of the control pulse in accordance with the load of the pump in order to rotate by a number. As a result, the output flow rate is proportional to the duty ratio, and if the relationship is expressed as a characteristic parameter, the output flow rate can be detected from the duty ratio.

[0006] Claim 2 is a water circulation device according to claim 1, wherein the flow control valve is adjusted before the operation of the pump, and the optional water circulation device is controlled.
The relationship between the point flow rate and the duty ratio is used as a characteristic parameter,
When the pump is operated, it is assumed that the relationship between the duty ratio and the flow rate is on a linear expression represented by a characteristic parameter, and a means for detecting the output flow rate of the pump from the measured duty ratio is provided. This makes it possible to detect the output flow rate by a simple calculation.

[0007] Claim 3 is a characteristic of the water circulating apparatus described in claim 1, wherein the result obtained by adjusting the flow regulating valve before the operation of the pump and performing regression analysis of a plurality of pairs of flow rate and duty ratio data is obtained. As a parameter, when the pump is operated, it is assumed that the relationship between the duty ratio and the flow rate is on a linear expression represented by a characteristic parameter, and a means for detecting the output flow rate of the pump from the measured duty ratio is provided. As a result, it is possible to detect the output flow rate with high precision while minimizing the variation of the pump by a simple calculation.

[0008] Claim 4 is a characteristic of the water circulating apparatus according to claim 1, wherein the flow control valve 10 is adjusted before the operation of the pump, and a curve complement between a plurality of pairs of flow rates and discrete data of the duty ratio is obtained. It has a function of detecting the output flow rate of the pump from the measured duty ratio, assuming that the relationship between the duty ratio and the flow rate is on the curve represented by the characteristic parameter 8 when the pump is operated. This makes it possible to detect the output flow rate with high accuracy even if the flow rate characteristic of the pump is non-linear.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The contents of the present invention will be described below with reference to examples in order to make it easier to understand.

[0010]

FIG. 1 is a conceptual diagram of a water circulation device according to the present invention, FIG. 2 is a flowchart of characteristic parameter calculation on claim page 2, and FIG. FIG. 4 is an operation flowchart for detecting the water amount from the duty ratio according to the present invention on claim page 2, FIG. 5 is a flowchart for calculating the characteristic parameters on claim page 3, and FIG. FIG. 7 is a flowchart showing the calculation of characteristic parameters on claim page 4, FIG. 8 is an operation flowchart for detecting the amount of water from the duty ratio of the present invention on claim page 4, and FIG. FIG. 10 is a diagram showing the relationship between the duty ratio and the amount of water (complementary expression) according to the present invention. FIG.

[0011] The water circulation device of the present invention, as shown in FIG.
The water in the water tank is circulated by the pump 1. That is, there is no head difference between the water inlet and the water outlet. Although the flow rate of water is adjusted by the flow rate adjusting valve 10, it is used for acquiring characteristic parameters, and thus may not be necessary during operation of the pump. Further, the characteristic parameters can be automatically set by automatically controlling the flow control valve.

The pump 1 is connected to the motor 2 and has a feedback system for rotating at a constant speed together with the pulse width modulation circuit 5 and the driver 3. The motor is a DC motor,
An AC motor may be used, and an appropriate power drive current suitable for the motor is supplied to the motor through the power supply circuit 4 and the driver 3. The motor outputs a rotation amount signal whose voltage is proportional to the rotation speed to the pulse width modulation circuit 5. The pulse width modulation circuit 5 calculates the difference between the current rotation speed and the target rotation speed from the rotation amount signal, and sends a control signal to the driver 3 so as to approach the target rotation speed. The control signal employs a method in which the motor current is controlled by the duty ratio of the pulse. The duty ratio is increased when the rotation speed of the motor is to be increased, and the duty ratio is reduced when the rotation speed is to be decreased. The driver 3 transmits to the motor a power drive current for the motor that is proportional to the duty ratio from the received control signal.

The control signal output from the pulse width modulation circuit 5 shown in FIG. FIG. 10 shows an embodiment of the duty ratio measuring means. In this example, the control signal output from the pulse width modulation circuit 101 is subjected to sampling and waveform shaping by the waveform shaping circuit 102 at a timing according to the clock of the reference clock generating circuit 104. This waveform is also synchronized with the timing generation circuit 103 synchronized by the reference clock generation circuit.
Then, a timing signal is generated for a High level clock counter 105 for measuring the High level time of the pulse and a cycle clock counter 106 for measuring the time of one cycle of the pulse. An interrupt signal synchronized with the pulse cycle is output from the timing generation circuit 103 to the microcomputer 1.
07, the microcomputer reads the High level time counter 105 and the period time counter 106, performs a calculation of duty ratio = High level time / cycle time, and performs a calculation process of obtaining the duty ratio. In this system, if the cycle time of the motor control pulse is constant, the cycle time counter 106 can be omitted.

Before operating the pump, characteristic parameters representing the relationship between the duty ratio and the output flow rate are stored in a memory beforehand by using the method described in claim pages 2, 3 and 4. The output flow is calculated from the pump-specific characteristic parameters obtained and retrieved from memory.

Thus, since the characteristic parameters are calculated for each pump, the output flow rate can be accurately detected without being affected by variations in the characteristics of the pump. Since the output flow rate is calculated based on the pulse time, it is hardly affected by the pump control circuit, and is resistant to external noise.

There are periods during which the duty ratio cannot accurately represent the output flow rate, such as when the pump motor requires torque, for example, when the rotation speed of the pump is increased. In such a period, the mask processing is appropriately performed so as not to calculate the output flow rate. If the change in the duty ratio is large due to the rotation speed fluctuation, the duty ratio averaging process is performed.

In claim page 2, as shown in FIG. 2, before the operation of the pump, the flow rate regulating valve of the pump is adjusted, and the duty ratio DA at a certain flow rate FA and the duty ratio DB at another flow rate FB are calculated. A straight line passing through the points is determined and used as a characteristic parameter. FIG. 3 shows a relationship graph between the duty ratio and the output flow rate. As shown in FIG. 4, during operation of the pump, the duty ratio is detected by the above method, and the flow rate is calculated from the straight line indicated by the characteristic parameter.

In claim page 3, as shown in FIG. 5, before the operation of the pump, the flow rate regulating valve of the pump is adjusted, several sets of the flow rate and the duty ratio at that time are measured, and regression analysis is performed statistically. A regression line is determined and used as a characteristic parameter. FIG.
FIG. 5 shows a relationship graph obtained by regression analysis between the duty ratio and the output flow rate. During the operation of the pump, the flow rate is calculated from the detected duty ratio from the regression line indicated by the characteristic parameter, as in the case of claim 2.

In claim 4, as shown in FIG. 7, before the operation of the pump, the flow rate regulating valve of the pump is adjusted, several sets of the flow rate and the duty ratio at that time are measured, and the flow is passed as much as possible near the measurement point. Is obtained and used as a characteristic parameter. FIG. 9 shows a relationship graph obtained by regression analysis between the duty ratio and the output flow rate. As shown in FIG. 8, during operation of the pump, the flow rate is calculated from the curve indicated by the characteristic parameter from the detected duty ratio.

[0020]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, it is possible to provide a water circulation device that accurately detects an output flow rate from a duty ratio of a control signal pulse of a pump. According to claim 2, it is possible to provide a water circulation apparatus having a calculation method of characteristic parameters suitable for a small-scale and simple water circulation apparatus that is easy to calculate. According to claim 3, it is possible to provide a water circulator having a method for calculating characteristic parameters of a small-scale water circulator that requires higher accuracy than claim 2. Claim 4 provides a large-scale water circulating device having a method for calculating characteristic parameters of the water circulating device that requires a high output flow rate detection accuracy because it is impossible to express the relationship between the duty ratio and the flow rate with a single straight line. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of a water circulation device according to the present invention.

FIG. 2 is a flowchart for calculating characteristic parameters in claim page 2;

FIG. 3 is a diagram showing a relationship between a duty ratio and a water amount according to the present invention in claim page 2;

FIG. 4 is an operation flowchart for detecting a water amount from a duty ratio according to the present invention in claim page 2;

FIG. 5 is a flowchart for calculating characteristic parameters in claim page 3;

FIG. 6 is a diagram showing a relationship (regression equation) between a duty ratio and a water amount in claim page 3;

FIG. 7 is a flowchart for calculating characteristic parameters in claim page 4;

FIG. 8 is an operation flowchart for detecting a water amount from a duty ratio according to the present invention on claim page 4;

FIG. 9 is a diagram showing the relationship (complementary expression) between the duty ratio and the water amount according to the present invention on claim page 4;

FIG. 10 shows an embodiment of the duty ratio measuring means of claim page 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pump, 2 ... Motor, 3 ... Driver, 4 ... Power supply circuit, 5 ... Pulse width modulation circuit, 6 ... Duty ratio measurement means, 7 ... Memory, 8 ... Characteristic parameters, 9 ... Microcomputer, 10 ... Flow control valve , 101: pulse width modulation circuit, 102: waveform shaping circuit, 103: timing generation circuit, 104: reference clock generation circuit, 105: Hig
h-level clock counter, 106: periodic clock counter, 1
07 ... microcomputer

Claims (4)

[Claims] 1. A water circulating device having a pump capable of keeping a rotation speed of a motor constant by adjusting a duty ratio of a pulse, wherein a means for measuring a duty ratio is provided, and a duty ratio stored in advance is provided. A water circulation device comprising: means for reading a characteristic parameter related to a flow rate and detecting an output flow rate of a pump from the measured duty ratio and the characteristic parameter. 2. In the water circulating apparatus, a flow rate adjusting valve is adjusted before operation of the pump, and a relation between a flow rate and a duty ratio at any two points is set as a characteristic parameter. When the pump is operated, a relation between the duty ratio and the flow rate is a characteristic parameter. 2. The water circulation device according to claim 1, further comprising means for detecting the output flow rate of the pump from the measured duty ratio, assuming that the primary flow rate is represented by the following equation. 3. In the water circulating apparatus, a flow control valve is adjusted before the operation of the pump, and a result obtained by regression analysis of a plurality of data of a pair and a duty ratio is used as a characteristic parameter, and the operation of the pump is performed. 2. The water circulation device according to claim 1, further comprising a function of detecting the output flow rate of the pump from the measured duty ratio, assuming that the relationship between the duty ratio and the flow rate is on a linear expression represented by a characteristic parameter. 4. In the water circulation device, a flow control valve is adjusted before the operation of the pump, and a result obtained by performing curve interpolation between a plurality of pairs of flow rates and discrete data of the duty ratio is used as a characteristic parameter. 2. The water circulation device according to claim 1, further comprising a function of detecting the output flow rate of the pump from the measured duty ratio, assuming that the relationship between the duty ratio and the flow rate is on a curve represented by the characteristic parameter.