JP2708280B2 - Fluidic gas meter with micro flow sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flowmeter with a microflow sensor in which measurement in a flow rate range below a predetermined flow rate is performed by an intermittent drive type microflow sensor, and measurement in a flow rate range above this flow rate range is performed by a fluidic element. It relates to a Dick gas meter.

[0002]

2. Description of the Related Art In the case of a fluid gas meter, a flow signal in a small flow rate region becomes unstable due to its characteristics.
In this small flow rate range, a method of measuring with a micro flow sensor is adopted.

Since this micro flow sensor is usually driven by a battery, an intermittent drive method is adopted for the purpose of minimizing power consumption and extending the life. In this intermittent drive method, the flow rate value is calculated for each intermittent drive time interval on the assumption that an instantaneous measurement value is continued for a fixed time (equivalent to the intermittent drive time interval).

In order to further improve the measurement accuracy of the intermittently driven micro flow sensor and to match the output of the fluidic element, in a certain flow rate range where the outputs from the flow sensor and the fluidic element are obtained simultaneously.
Compare both outputs, and if this difference exceeds a preset range, obtain a correction value that matches the output of the fluidic element side and calculate the flow rate.This correction value is
Similarly, it is used as a correction value until the next correction value is obtained.

[0005]

For this reason, noise is included in the output at the time of correction, and if a correction value is determined based on an output that is deviated by the noise, it takes a long time to obtain the next correction value. In addition, there is a problem that the flow rate is calculated based on the incorrect correction value and the flow rate is integrated.

Of course, improvement can be considered by shortening the drive time interval of the micro flow sensor.
This increases power consumption and shortens battery life.

It is an object of the present invention to prevent long-term flow calculations from being performed based on incorrect correction values.

[0008]

The configuration of the present invention is as follows.

[0009] Measurement in a flow rate range below a predetermined flow rate is performed by an intermittent drive type micro flow sensor, and measurement in a flow rate range above this flow rate range is performed using a fluidic element. The output of the micro-flow sensor is compared with the output of the fluidic element when both outputs are compared in a certain flow rate range where the output of the fluidic element is output at the same time. An automatic correction circuit for changing a correction value by which a measured value is multiplied, wherein the intermittent drive time interval of the micro flow sensor is configured to be driven at a shorter time interval than a normal measurement time interval. Fluidic gas meter.

[0010]

The micro flow sensor is intermittently driven by the drive circuit and outputs a flow signal. This drive interval is usually on the order of several seconds.

On the other hand, the fluidic element constantly generates fluid vibration, and outputs the vibration, that is, the flow rate as an electric signal. The arithmetic circuit calculates the flow rate based on the signals from both, integrates the flow rate, and displays the result on, for example, a display unit.

In the flow signal output in this manner, a certain flow range is determined as a corrected flow range, and when the flow rate enters the corrected flow range, both outputs are automatically compared with each other and the output is determined in advance. If a difference equal to or greater than the difference occurs, a certain correction value is calculated in order to match the output of the micro flow sensor to the output of the fluidic element side, and this correction value is used as a correction value until the subsequent automatic correction is applied. Is used to calculate the flow rate. This is automatic correction.

Normally, the drive time interval of the micro flow sensor is performed in units of several seconds, and the time interval at the time of this automatic correction is also the same. Therefore, if noise enters, at least during this drive time interval, The correction value is determined based on the output based on the noise, and the flow rate integration is performed. The flow rate integration based on such an incorrect correction value is not so problematic when the time interval until the next correction is performed is short, but depending on the use situation, the flow integration until the next automatic correction flow rate range is reached. The time may be long, for example lasting several hours.

According to the present invention, when the automatic correction flow rate is entered, the drive time interval of the micro flow sensor is set to, for example, 1/10 of the normal one.
It is set to 0. For this reason, when entering the automatic correction flow rate range, the micro flow sensor is driven intensively, and even if noise enters, a normal output is immediately input next, so an incorrect correction value is used. The time taken can be reduced to almost negligible. Also, the probability that an incorrect correction value remains will be very small.

[0015]

FIG. 1 shows the present invention.

Reference numeral 1 is a micro flow sensor.
The micro flow sensor 1 is incorporated in a nozzle of a fluidic element. Reference numeral 2 denotes a micro flow sensor driving circuit for driving the micro flow sensor 1 at regular time intervals, 3 denotes an arithmetic unit, 4 denotes an output signal from the micro flow sensor 1 and a fluidic element 8 and the fluidic element 8 A flow rate calculation circuit that calculates a flow rate based on an output signal from a fluid vibration detection sensor 9 that detects a fluid vibration to be generated and displays the flow rate on the display unit 5.

6 is the micro flow sensor drive circuit 2
A drive time control circuit that outputs a control signal to
The micro flow sensor drive circuit 2 drives the micro flow sensor 1 based on the signal output from the drive time control circuit 6.

Reference numeral 7 denotes a mode switching unit. When the correction mode is selected here, the drive time control circuit 6 outputs a drive time interval of n seconds for correction with respect to a normal time interval of m seconds, and outputs a micro time. The flow sensor 1 is driven.

As a result, assuming that n = m / 100, the micro flow sensor 1 is only 1/100 of the normal state during the correction.
At time intervals of

The correction mode is manually selected at the time of setting the initial correction value, and is performed by the drive time control circuit 6 receiving a signal indicating that the correction execution condition is satisfied from the flow rate calculation circuit 4 at the time of performing the automatic correction.

FIG. 2 is an explanatory diagram of this automatic correction. In the case of the embodiment with respect to a normal drive time interval of m seconds, the measurement is performed at m / 100 second intervals during the execution of the automatic correction.

[0022]

As described above, according to the present invention, the micro flow sensor is driven at an extremely short time interval with respect to the normal drive time interval at the time of initial setting of the correction value or at the time of automatic correction. The following effects can be expected.

A. Incorrect correction values are not used for a long time due to noise during automatic correction. As a result, an accurate integrated flow value can be obtained, and the probability that an incorrect correction value remains remains extremely small.

B. Since the drive time interval of the micro flow sensor is shortened only at the time of correction, power consumption is small, and the life of the battery is not significantly affected.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a gas meter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Micro flow sensor 2 Micro flow sensor drive circuit 3 Computing unit 4 Flow rate operation circuit 5 Display unit 6 Drive time control circuit 7 Mode switching unit 8 Fluidic element 9 Fluid vibration detection sensor

Claims (1)

(57) [Claims] 1. A fluid gas meter of a type in which measurement in a flow rate range below a predetermined flow rate is performed by an intermittent drive type micro flow sensor, and measurement in a flow range above this flow rate range is performed by a fluid element. In a certain flow rate range where the output from the sensor and the output from the fluidic element are output simultaneously, the outputs from both are compared, and when the difference between these outputs exceeds a preset range, the microflow sensor side In the automatic correction circuit that changes the correction value by which the output measurement value is multiplied,
A fluidic gas meter with a microflow sensor, wherein the intermittent driving time interval of the microflow sensor is configured to be driven at a shorter time interval than a normal measurement time interval.