JP3044935B2 - Flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter such as an electronic water meter or gas meter.

[0002]

2. Description of the Related Art In a flow meter such as a water meter or a gas meter, the number of revolutions of a rotating body such as an impeller is detected by a magnetic conversion element and converted into an electric signal. The electronic type which measures the amount of used is used.

In such an electronic type flow meter, two sets of sensor units for detecting the number of rotations are provided to detect whether the flow direction is forward flow or reverse flow, and the output signal of one sensor unit is used to detect the flow rate of the other sensor. One sensor unit is shifted in the rotational direction with respect to the other sensor unit so as to obtain a signal advanced by 90 degrees in electrical angle from the output signal of the unit, and the phase of the output signals of both sensor units And a forward / reverse determining unit that determines whether the flow is normal or reverse depending on which sensor unit has advanced output signal phase.

[0004] Since such an electronic meter is usually driven by a battery, it is necessary to reduce power consumption and prolong the life of the battery. Therefore, in order to reduce the power consumption of the sensor unit, which consumes a large amount of power, a sampling method in which the average current is reduced by intermittently applying the power supply voltage applied to the sensor unit for a short period of time is adopted. If the value is below a certain value or above a certain value where backflow does not occur, power is not supplied to one of the sensor units, and the power consumption of the sensor unit during standby or at a large flow rate can be halved. This was done by an emergency backflow detection method that can be used.

[0005]

However, in the above-mentioned conventional emergency backflow detection method, the power supply to the sensor unit for detecting the direction of the flow is controlled by the flow rate. There is a problem in that the degree of conversion is different, and in some cases, the effect is almost lost, or the simulation at the time of design cannot be performed because the effect differs depending on the use condition, and the battery life cannot be guaranteed.

Since the detection of the backflow is performed by counting the pulses of the output signal of the sensor section, it is sufficient to detect the backflow every time a pulse is input to the integrating section. In this case, since the power supply to the two sensor units is performed at the same timing, a current is supplied to the sensor units for detecting the direction of the flow even when it is not necessary, and power is wasted.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a flow meter which does not detect the flow direction more than necessary and consumes less power.

[0008]

In order to solve the above-mentioned problems, a flow meter according to the present invention detects a flow rate and a flowing direction, and outputs a first sensor section and a second sensor section having different phases of output signals.
Sensor unit, a power supply unit for driving the first sensor unit and the second sensor unit, a forward / reverse determining unit for determining whether the flow is forward or reverse, and a A phase detection unit that detects a predetermined phase; and a power supply control unit that supplies power from the power supply to the first sensor unit according to an output timing of the phase detection unit.

[0009]

In the above arrangement, the second sensor converts the flow rate into an electric signal and transmits the electric signal to the integrating section and the phase detecting section.
The phase detector detects a rise or a fall of the output signal of the second sensor unit. The power supply controller is
First time for a fixed time according to the signal timing from the phase detector
The power supply is supplied to the sensor unit of, and the direction of the flow can be detected. On the other hand, the forward / reverse determination unit detects the output signal of the first sensor unit according to the signal timing from the phase detection unit and determines whether the flow is normal or reverse.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment in which power is supplied to the first sensor unit when the output signal of the second sensor unit changes from logic 0 to 1. In the figure, 1 is a first sensor unit, 2 is a second sensor unit, 3 is a forward / reverse determination unit, 4 is an integration unit, 5 is a phase detection unit, 6 is a power supply unit, 7 is a power supply control unit, 8 Is a flow meter. FIG. 2 is a flowchart for explaining the operation of the flow meter, and FIG. 3 is a time chart for explaining the operation of the flow meter.

The first sensor unit and the second sensor unit output rectangular waves having phases different from each other and having a frequency corresponding to the flow rate when power is supplied for detecting the flow rate and the flow direction. It is provided in. In this embodiment, the signal MR1 of the first sensor unit is delayed by about 90 degrees in electrical angle from the signal MR2 of the second sensor unit in the forward flow, and is advanced by about 90 degrees in the reverse flow. The second sensor unit 2 is constantly supplied with power from the power supply unit 6 and outputs a signal MR2 having a frequency corresponding to the flow rate.

Now, when the signal MR2 of the second sensor unit is at logic 0 (t1 to t2), the rising of the signal is not detected by the phase detection unit 5, so that the power supply control unit 7 The power supply from the power supply unit 6 is not performed.
When the output signal MR2 of the second sensor unit changes from logic 0 to 1 (t2), the phase detection unit 5 detects this (a).
The power is supplied to the power supply control unit 7, and the power supply control unit 7 supplies power to the first sensor unit 1 (b). On the other hand, the forward / reverse determining unit 3 compares the phases of the signals of the first sensor unit 1 and the second sensor unit 2, so that the first sensor unit to which the power is supplied is determined by the timing transmitted from the phase detecting unit 5. 1 signal M
R1 is input and held (c), and at the time of backflow, a backflow signal of logic 1 is generated and transmitted to the integrator 4. The accumulator 4 responds to the input of the signal MR2 from the second sensor 2 (d),
If there is a backflow signal, subtraction is performed from the integrated flow rate (f), and if there is no backflow signal, it is added to the integrated flow rate (e).

Similarly, when the output signal of the second sensor unit 2 is logic 1, the power supply control unit 7 does not supply power from the power supply unit 6 to the first sensor unit 1 (g). By supplying power to the first sensor unit 1 for a certain period of time (t to t3) when a backflow is detected, power consumption is suppressed.

[0015]

Since the flowmeter of the present invention is configured as described above, the supply of power to the first sensor unit for detecting the flow direction is performed by the second flowmeter for detecting the flow rate. The power is supplied only when it is necessary to detect the direction of the flow, so that the power can be effectively used without waste. In addition, the current consumption is also reduced regardless of the flow rate, and the degree of reduction in the current consumption does not vary greatly depending on the usage conditions. This has the effect of guaranteeing the battery life.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a flow meter according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the flow meter.

FIG. 3 is a time chart for explaining the operation of the flow meter.

FIG. 4 is a block diagram showing a configuration of a conventional flow meter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first sensor unit 2 second sensor unit 3 forward / reverse determination unit 4 integration unit 5 phase detection unit 6 power supply unit 7 power supply switching unit 8 operation unit 9 flow meter

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 15/075

Claims (1)

(57) [Claims] An output signal has a phase different from each other and detects a flow rate and a flow direction. A phase of an output signal of a first sensor section and a second sensor section and a phase of an output signal of the second sensor section are detected. A phase detector, a forward / reverse determiner that determines the direction of flow in accordance with an output signal from the first sensor, and a controller for the first sensor in response to an output signal from the phase detector. A flow meter including a power supply control unit for controlling power supply.