JPH05273003A - Controlling device for fluidic meter - Google Patents

Abstract

PURPOSE:To enable accurate measurement of a flow rate by a method wherein a flow rate conversion value showing the relation between the flow rate and an output signal of a flow rate detecting means is stored, with its natural nonlinear characteristic unchanged, in a flow rate conversion value storage means. CONSTITUTION:When a gas is used, an oscillation frequency of a fluidic oscillation element 3 is detected by an oscillation detecting means 20. In the case of an area of a small flow rate, the number of pulses corresponding to a flow velocity is detected by a flow velocity detecting means 21. A flow rate conversion value showing the relation with an output signal of a flow rate detecting means 19 is stored, with its natural nonlinear characteristic unchanged, in a flow rate conversion value storage means 22. A flow rate setting means 23 determines a flow rate on the basis of a coefficient stored in the storage means 22 and corresponding to the output signal of the detecting means 19 and of a detection signal. In another method, a flow rate value stored in the storage means 22 is searched for on the basis of the output signal of the detecting means 19 and the flow rate corresponding to the output signal is set. Then, the determined flow rate is added up to determine an integrated flow rate in an integrated flow rate computing means 24 and the value of the integrated flow rate is displayed 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidic meter for measuring the flow rate of a fluid such as city gas or LPG gas, and more particularly to a control device having a high speed arithmetic function.

[0002]

2. Description of the Related Art Conventionally, a fluidic meter control device of this type has a structure as shown in FIG. 2 as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-95420.

That is, in the conventional fluidic meter control device shown in FIG. 2, 1 is a fluidic meter and 2 is a fluidic meter.
Is a gas pipe, and 3 is a fluidic oscillation element, which causes fluid oscillation by utilizing the kinetic energy of the fluid. Four
Is a sensor that detects the frequency of fluid oscillation. A shutoff valve 5 shuts off the gas supply when an abnormal use state is detected. 6 is a control device, an example of which is shown in FIG.

In FIG. 3, 7 is an analog amplifier, which is a sensor 4
The flow rate signal detected at is amplified. 8 is a waveform shaping circuit,
The amplified signal is converted into a pulse signal. A rising point detection circuit 9 detects the rising of the flow rate pulse signal. Reference numeral 10 denotes a cycle measuring means, which measures the time from the rising point of the flow rate pulse to the next rising point, that is, the cycle. Reference numeral 11 is a memory circuit, and the relationship between the pulse constant and the flow rate or period is approximated by n polygonal lines. Unit time storage means 13 for storing,
Correction unit amount means 1 for storing the correction unit amount α of the pulse constant
4 and constant storage means 15 for storing the constant term a. These storage means are provided in units of n corresponding to the division of n broken lines. Reference numeral 16 denotes an adder circuit which calculates and adds a pulse constant K = a + Σα indicating a flow rate per pulse for each cycle. Reference numeral 17 denotes an integrating circuit, which integrates the calculated flow rate. Reference numeral 18 denotes a display, which displays the integrated result.

Next, the operation of the above conventional configuration will be described.
When some kind of gas instrument is used, the gas enters the fluidic oscillation element 3 to cause fluid oscillation, and the sensor 4 detects a change in the flow rate. The output signal of the analog amplifier 7
And the waveform shaping circuit 8 converts it into a pulse signal.

The relationship between the flow rate and the oscillation frequency is Q = a · F + b
Given in. This is the formula K for obtaining the flow rate per pulse
= Q / F = a + b · T. Here, K is called a pulse constant and indicates a flow rate value per pulse. a and b are coefficients. The relationship between the pulse constant and the flow rate or the vibration frequency is not constant as shown in FIG. When the period of the flow rate pulse exceeds the boundary of the polygonal line approximation, the coefficient is changed to calculate the pulse constant. Therefore, the coefficient is set for each broken line segment. Further, here, the multiplication process of b · T is not performed but the addition process is performed, and the pulse constant K is obtained.

The contents will be described. First, the rising point detection circuit 9 detects the rising of the flow rate pulse output from the waveform shaping circuit 8. When the rising edge is detected, the cycle measuring means 10 starts measuring the cycle of the flow rate pulse. At the same time, the adder circuit 16 performs the following processing. Instead of calculating b · T, a unit correction amount α much smaller than the value of b · T is added to obtain. The addition is performed every unit correction time t, which is a time period relatively shorter than the cycle T of the flow rate pulse. Therefore, it can be said that α = b · t. Therefore, the unit correction amount α is continuously added every time the unit time t elapses from the rising point to the detection of the next rising point for one cycle of the flow rate pulse. The resulting K
= A + Σα is the flow rate per pulse, that is, the pulse constant. Since the relationship between the pulse constant and the period of the flow rate pulse is approximated by a polygonal line, each polygonal line segment has a coefficient a, a unit correction amount α, and a unit correction time t. Therefore, the adder circuit 16 determines whether the period measured by the period measuring means 10 has reached the period of the boundary of the polygonal line section, and if it enters the area of the next polygonal line section, the coefficient a, the unit correction amount α, the unit correction. The time t is changed and the above processing is continued. As shown in FIG. 5, in T1 to T2, α1, t1, T2 to T
In 3, the addition is performed by switching to α2 and t2. The period measuring means 10 has a function of measuring the pulse period and also having a function of determining whether or not the period of the boundary of the polygonal line has been reached.

The flow rate thus obtained is used for the integrating circuit 17
The cumulative value used can be obtained by adding in. This integrated value is displayed on the display unit 18.

[0009]

However, in the above-mentioned conventional configuration, since the pulse constant indicating the relationship between the flow rate and the vibration frequency (or period) is linearly approximated, the error becomes large especially near the boundary of the polygonal line and the flow rate is reduced. There was a problem that it could not be measured accurately and that it also had a large effect on the integrated flow rate value.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fluidic meter capable of accurately measuring a flow rate.

[0011]

In order to achieve the above object, the present invention provides a flow rate detecting means for detecting a fluid flow rate, and a characteristic value indicating a non-linear relation between a detection signal of the flow rate detecting means and the flow rate. A stored flow rate conversion value storage means and a flow rate setting means for determining the characteristic value stored in the flow rate conversion value storage means from the output signal of the flow rate detection means are provided.

[0012]

According to the present invention, the flow rate detecting means detects the fluid flow rate, and the flow rate setting means stores it in the flow rate conversion value storage means to obtain the characteristic value corresponding to the detection signal based on the detection signal. The flow rate is set from the characteristic value and the integrated flow rate is calculated from the value. Since the characteristic value is stored in the flow rate conversion value storage means as it is non-linear, the flow rate can be obtained quickly.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1, the same components as those in FIG. 3 are designated by the same reference numerals.

FIG. 1 is a control block diagram of a fluidic meter controller of the present invention. In FIG. 1, reference numeral 19 denotes a flow rate detecting means, for example, a fluidic oscillation element 3 for measuring a large flow rate region and a vibration detecting means 20 for detecting a fluid oscillation frequency generated therein (for example, a pressure-voltage using a piezoelectric sensor, a thermistor or the like). Change, heat-resistance change), and a flow velocity detecting means 21 for measuring a small flow rate region.
(Heat-wire type sensor, etc.) and so on. Reference numeral 22 denotes a flow rate conversion value storage means, which indicates a relationship between the flow rate and the output signal of the flow rate detection means, and stores a coefficient having a non-linear characteristic in advance, or a flow rate value corresponding to the output signal of the flow rate detection means 19. Is stored. Reference numeral 23 is a flow rate setting means, which detects the output signal of the flow rate detecting means 19 and the flow rate conversion value storage means 22.
The flow rate is obtained from the coefficient stored in the above, or the flow rate value stored in the flow rate conversion value storage means 22 is searched based on the detected output signal of the flow rate detecting means 19 to obtain the corresponding flow rate value. Reference numeral 24 is a flow rate integrating means for integrating the obtained flow rates to obtain an integrated value. A display means 18 displays the integrated value.

Next, the operation of the above configuration will be described. When the gas starts to be used, the flow rate detecting means 19 detects the flow rate. For example, the gas in the gas pipe 2 is the fluidic oscillation element 19
Through the fluidic oscillation element 19
Then, fluid oscillation occurs due to the Coanda effect. The oscillation detecting means 20 detects this oscillation frequency as a voltage signal. Alternatively, in the case of a small flow rate region, the flow velocity detecting means 21 outputs the number of pulses corresponding to the flow velocity.

Next, the flow rate setting means 23 determines the flow rate based on the signal detected by the flow rate detecting means 19. First, the flow rate is calculated and obtained from the coefficient corresponding to the output signal of the flow rate detection means 19 stored in the flow rate converted value storage means 22 and the detected signal. Alternatively, as another method, the flow rate corresponding to the output signal is set by searching for the flow rate value stored in the flow rate conversion value storage means 22 based on the output signal of the flow rate detecting means 19. The flow rate thus obtained is added by the integrated flow rate calculation means 24 to obtain the integrated flow rate. And display means 18
Displays the calculated integrated flow rate value.

According to the structure of this embodiment, since the flow rate conversion value indicating the relationship between the flow rate and the output signal of the flow rate detection means is stored in the flow rate conversion value storage means 22 as it is, the flow rate is obtained quickly. In addition, the consumption of the battery power source that drives the whole can be suppressed.

[0018]

As described above, the fluidic meter control device of the present invention has a flow rate detecting means for detecting the flow rate of a fluid, and a flow rate conversion value indicating a non-linear relationship between the detection signal of the flow rate detecting means and the flow rate. And a flow rate setting means for setting the flow rate converted value stored in the flow rate converted value storage means from the output signal of the flow rate detection means. The relationship between the flow rate and the output signal of the flow rate detection means Since the flow rate conversion value indicating the above is stored in the flow rate conversion value storage means as it is, it is possible to obtain the flow rate faster and to suppress the consumption of the battery power source that drives the whole as compared to the case of linear approximation. effective.

[Brief description of drawings]

FIG. 1 is a block diagram of a fluidic meter control device according to an embodiment of the present invention.

[Fig. 2] System configuration diagram of a conventional fluidic meter control device

FIG. 3 is a control block diagram of the device.

FIG. 4 is a characteristic diagram of the device.

FIG. 5 is a characteristic diagram illustrating the characteristics of the device in more detail.

[Explanation of symbols]

 19 flow rate detection means 22 flow rate converted value storage means 23 flow rate setting means

Claims (1)

[Claims] 1. A flow rate detecting means for detecting a flow rate of a fluid, a flow rate conversion value storing means for storing a characteristic value showing a non-linear relationship between a detection signal of the flow rate detecting means and the flow rate, and the flow rate detecting means. And a flow rate setting means for determining the characteristic value stored in the flow rate converted value storage means from the output signal of the above.