JP3024873B2 - Fluidic gas shut-off device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas meter which measures the flow rate of fluid such as city gas or propane gas and shuts off the supply of gas when an abnormal condition is detected. The present invention relates to a gas shutoff device.

[0002]

2. Description of the Related Art A conventional fluid gas shut-off device is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-96817, as shown in FIGS.

In the conventional fluid gas shut-off device shown in FIGS. 3 and 4, reference numeral 1 denotes a fluid oscillation element, reference numeral 2 denotes a jet nozzle, and a gate 2 at the center of a nozzle gate 2a.
The nozzles are formed in the central part so that a faces each other.

[0004] Reference numeral 3 denotes a target arranged at the front center of the ejection nozzle 2 for clearly switching the flow. Reference numerals 4 and 4a denote adhering walls on both front sides of the ejection nozzle, reference numerals 5 and 5a denote feedback channels, reference numerals 6 and 6a denote control nozzles, and reference numeral 7 denotes a chevron plate. In the fluidic oscillation element 1, the fluid to be measured is ejected from the ejection nozzle 2 toward the target 3. When the fluid to be measured adheres to the adhering wall 4 or 4a by the Coanda effect and flows, a part of the fluid enters the feedback flow paths 5 and 5a, through which pressure is transmitted, and the control nozzle 6 , 6a. As a result, the fluid is forcibly separated from the adhesion wall 4 or 4a, and adheres to the opposite adhesion wall 4 or 4a side.

[0005] Reference numeral 10 denotes a vibration detecting means, which is a piezoelectric sensor for detecting fluid vibration. It has a pair of pressure introduction ports 11 and 11a that open to the feedback flow paths 4 and 4a, and the pressure introduction path 12 communicates with the pressure introduction port 11. The vibration detecting means 10 detects a differential pressure between two points of the feedback flow paths 5, 5a to detect vibration. 13 is a flow sensor,
It is a thermal flow sensor. Although not shown, a heat generating part and a gas temperature detecting part are arranged on the flow sensor 13.

FIG. 4 shows an electronic circuit for detecting a vibration from the above two sensors and obtaining a flow rate. In FIG. 4, reference numeral 14 denotes a piezoelectric sensor circuit block, which includes an AMP 15 for amplifying a signal to the piezoelectric sensor 10 and a waveform shaping circuit 16. Reference numeral 17 denotes a flow sensor circuit block, which includes a flow sensor 13 and an A / D conversion circuit 18. Reference numeral 19 denotes a signal determination circuit which receives a signal from the piezoelectric sensor circuit block 14, determines whether or not the frequency is equal to or higher than a predetermined value, and transmits the signal to the microcomputer 20 when the frequency is equal to or higher than the predetermined value. Reference numeral 21 denotes a counter which counts signals from the flow sensor circuit block 17 and temporarily stocks them for input to the microcomputer 20. A clock circuit 22 receives a signal from the microcomputer 20 and outputs the signal to an A / D conversion circuit. Reference numeral 23 denotes a power supply control circuit which receives a control signal from the microcomputer 20 and a flow sensor circuit block 17.
Power supply control. The microcomputer 20 receives the signal from the signal determination circuit 19 or the signal from the counter 21 and calculates the flow rate, and displays the integrated value on a display 24.

Next, the operation of the above configuration will be described. When any gas equipment is used, the gas enters the fluid oscillation element 1. The gas ejected from the jet nozzle 2 adheres to one of the adhering walls 4 or 4a and flows. Some gas reaches the feedback flow paths 5, 5a, from which pressure is transmitted to the control nozzles 6, 6a, forcibly changing the gas flow path. The above operation is repeated while the gas is supplied to the device. At this time, the switching period of the flow path (oscillation frequency of the fluid) is detected by the piezoelectric film sensor 10 and converted into a pulse by the waveform shaping circuit 16 to be converted into a pulse by the signal determination circuit 1.
In step 9, it is determined whether the frequency is equal to or higher than a predetermined frequency. If the frequency is equal to or higher than a certain frequency, it is input to the microcomputer 20. Conversely, when the frequency is equal to or lower than the certain frequency, the signal output from the waveform shaping circuit 16 is stopped, and the signal of the flow sensor 13 is input to the microcomputer 20. Flow sensor 13
Is a thermal type, the temperature changes according to the fluid flow rate, that is, the resistance value changes. A / D conversion circuit 1
At 8, the number is converted to the number of pulses. After the number of pulses is measured by a counter, it is input to the microcomputer 20 for processing.

[0008]

However, in the above-mentioned conventional configuration, two types of sensors are required to measure the flow rate from the low flow rate range to the large flow rate range. Since the flow rate conversion method at the time of switching the sensor is different, the processing becomes complicated, and the program capacity of the microcomputer increases. Furthermore, since the flow sensor 13 is of a thermal type, there is a problem that an error occurs depending on the temperature of the measurement fluid.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a fluidic gas shut-off device which can measure a flow rate with a sensor and measure the flow rate without being affected by the temperature of a fluid. .

[0010]

In order to achieve the above object, the present invention provides a fluid oscillation device for oscillating a fluid at a frequency corresponding to the flow rate of a fluid, and detecting a frequency of the fluid oscillation generated by the fluid oscillation device. Vibration detection means, a width variable means for varying the jet nozzle width of the fluid oscillation element, and a jet width control means for automatically controlling the position of the width variable means based on the signal of the vibration detection means, Is provided.

[0011]

According to the present invention, the jet width of the fluid oscillation element is set to a default value in advance by the above configuration.
When the use of any device is started, fluid oscillation occurs in the fluid oscillation device due to the Coanda effect. The fluid oscillation frequency is detected by the vibration detection means, and then the jet width control means determines whether the detected vibration frequency is equal to or higher than a predetermined value. When the width is equal to or more than the predetermined value, the width varying means is energized to automatically vary the jet nozzle width of the fluid oscillation element.
At the same time, when the position of the width varying means is detected and reaches a set value, the drive of the width varying means is stopped and held at that position.

As described above, since the jet width of the fluid oscillation element is automatically varied, the flow rate of the fluid can be measured by one sensor, so that it is not necessary to provide a plurality of sensors and perform complicated processing.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIGS. 1 and 2, FIGS.
The same reference numerals are given to the same components.

FIG. 1 is a control block diagram of the fluidic gas shut-off device of the present invention. In FIG. 1, reference numeral 25 denotes a fluidic oscillation element which is provided in the middle of a gas pipe and causes fluid oscillation using kinetic energy of a fluid. 26 is a vibration detecting means for detecting the oscillation frequency of the fluid as a change in heat-resistance, a change in a magnetic field, or an optical change using, for example, a pressure change, a thermistor or the like.

Reference numeral 27 denotes a jet width variable means, which comprises jet width determining means 27a, position detecting means 27b, and variable width driving means 27c. The jet width determining means 27a determines, based on the vibration frequency of the fluid detected by the vibration detecting means 26, whether or not the frequency is, for example, a predetermined value or more, and sets the position of the jet width. The position detecting means 27b detects the position of the width varying means 28 for varying the jet width. The variable width driving means 27c drives the variable width means 27c so as to correct the difference between the output signals of the jet width determining means 27a and the position detecting means 27b. The width varying means 28 continuously varies the jet nozzle width of the fluid oscillation element 8.

Reference numeral 29 denotes a flow rate calculating means,
The fluid flow rate is calculated and obtained from the vibration frequency of the gas fluid detected in step (1). Reference numeral 30 denotes an integrated flow rate calculating means for obtaining an integrated flow rate of the used gas. Numeral 31 is a determining means for determining whether or not the gas usage state is normal based on the integrated flow rate and the flow rate. Numeral 32 denotes a display means for displaying the integrated flow rate or the content at the time of abnormality. Reference numeral 33 denotes a shut-off means, which is constituted by, for example, a pulse-driven electromagnetic valve, and stops the gas supply when the judging means 31 judges an abnormal use condition.

FIG. 2 shows an embodiment of the variable width means 28. FIG. 2 is a top view of the fluidic oscillation element 25 as viewed from above by taking a lid thereof. The ejection nozzle 2 is opposed to the width varying means 28. The width varying means 28 includes a variable nozzle means 28a and a nozzle driving means 28b. 2
Reference numeral 8b denotes a piezoelectric driving element, for example, which drives the variable nozzle means 28a according to the applied voltage and moves left and right.

Next, the operation of the above configuration will be described. When the gas equipment starts to be used, gas starts to be ejected from the jet nozzle 2 in the fluidic oscillation element 25. The gas fluid flows by adhering to the adhering wall 4 or 4a by the Coanda effect. A part of the gas fluid adhering and flowing enters the feedback channel 5 or 5a and is transmitted as a pressure change to the control nozzle 6 or 6a to forcibly change the channel. The remaining gas is supplied to the device from the outlet.

Next, the cycle of the flow path change, that is, the vibration frequency of the fluid is detected by the vibration detecting means 26. Based on the frequency detected by the vibration detecting means 26, it is determined whether or not the jet width and the detected frequency are within a predetermined value range by the jet width control means 27. Next, if the jet width is not within the predetermined value range, the jet width is adjusted to an appropriate position. Specifically, first, the jet width determining means 27a determines whether the detected frequency is higher or lower than a boundary frequency that can be accurately detected by the jet width at that time, and determines the displacement amount of the width varying means 28. The variable width driving means 27c is
To increase or decrease the jet nozzle width of the fluidic oscillation element 25. The position detecting means 27 b is provided with a default value of the jet width and the variable width driving means 27.
The difference from the displacement amount due to c is obtained, and the position of the width varying means 28 is detected. Here, the position detecting means 27b has a method of measuring a position with time, counting a feed amount, or the like.
The width varying means 28 reduces the pressure loss by enlarging the jet flow width, and makes it possible to accurately measure the gas flow rate in a large flow rate range.
Conversely, when the oscillation frequency decreases, the jet width is narrowed to prevent the oscillation from becoming difficult in a small flow rate range, and the accuracy of the flow rate measurement is improved. By setting the jet nozzle width of the fluidic oscillation element 25 suitable for the flow rate range measured according to the vibration frequency as described above,
The relationship between the flow rate and the vibration frequency can be obtained with high accuracy. In this way, the flow rate is obtained by calculation from the vibration frequency detected by the flow rate calculating means 29. Then, the integrated value of the gas flow rate used by the integrated flow rate calculating means 29 is obtained.
Based on the obtained flow rate and the integrated flow rate, the determining means 31 determines whether or not an abnormal use state is present. If the use state is normal, the integrated value is displayed on the display means 32. Drive and stop gas supply.

Here, the adjustment of the width of the jet nozzle 2 will be described with reference to FIG. The jet nozzle width is initially set to the default width. If the variable driving means 28b is constituted by, for example, a piezoelectric driving element, the width variable driving means 27c
A voltage signal is output. As a result, a mechanical displacement occurs and the variable nozzle means 28a is urged, so that the width of the jet nozzle 2 becomes larger or smaller.

As described above, the vibration frequency is detected by adjusting the width of the jet nozzle 2 and the flow rate is determined based on the frequency.
Further, an integrated flow rate is obtained. The judging means 31 judges whether or not the gas use condition is abnormal based on the flow rate value and the integrated flow rate value at that time, and if abnormal, drives the shut-off means 33 to stop the gas supply. The display means 32 normally displays the integrated flow rate value, and displays the shutoff content when an abnormality occurs.

Therefore, according to the structure of this embodiment, when the gas is started to be used, the width of the jet nozzle 2 of the fluidic oscillation element 25 is automatically adjusted to an optimum value in accordance with the vibration frequency. The use of a single fluidic sensor that does not require temperature correction or the like eliminates the need to use many sensors and eliminates the complexity of temperature characteristic correction processing that occurs due to the use of multiple sensors. There is an effect that the flow rate can be measured up to a large flow rate range of 50001 / h.

[0023]

As described above, the fluidic gas cutoff device of the present invention comprises a fluidic oscillation element for oscillating a fluid at a frequency corresponding to the flow rate of a fluid, and a frequency of fluid oscillation generated by the fluidic oscillation element. From the vibration detecting means, the width varying means for varying the jet nozzle width of the fluidic oscillation element, and the jet width control means for controlling the position of the width varying means based on the signal of the vibration detecting means. becomes, so to adjust according to the oscillation frequency automatically optimum jet nozzle width of a fluidic oscillator begins to use the gas, each time manually not set the nozzle width
Spend time, measure each time you set, and fine-tune manually
The nozzle width can be automatically adjusted to the optimum value without any trouble such as
And hitherto without using many sensors as, i.e., without the complexity of conversion processing with the correction processing and the measurement range switching temperature characteristic which occurs for multiple use sensors, simply one With this sensor, a fluidic sensor that does not require temperature correction or the like has the effect that the flow rate can be measured from a small flow rate range to a large flow rate range.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a fluid gas shutoff device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a width varying unit of the apparatus.

FIG. 3 is an external perspective view of the inside of a conventional fluidic meter gas shut-off device.

FIG. 4 is a block diagram showing a jet nozzle configuration of the apparatus.

[Explanation of symbols]

 25 Fluidic oscillation element 26 Vibration detecting means 27 Jet width control means 28 Width variable means

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Ueki 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Koichi Takemura 1006 Odaka Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Takashi Ueki 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Inventor Katsato Sakai 1-5-20 Kaigan, Minato-ku Tokyo (72) Inventor Shigenori Okamura 4-1-2, Hirano-cho, Chuo-ku, Osaka City Inside Osaka Gas Co., Ltd. (72) Inventor Yasuo Sato 19-18 Sakuradacho, Atsuta-ku, Nagoya City, Aichi Prefecture Toho Gas Co., Ltd. 72) Inventor Yukio Kimura 19-18 Sakuradacho, Atsuta-ku, Nagoya City, Aichi Prefecture Inside Toho Gas Co., Ltd. nt.Cl. ⁷ , DB name) G01F 1/20

Claims (1)

(57) [Claims] 1. A fluidic oscillating element for oscillating a fluid at a frequency corresponding to the flow rate of a fluid, vibration detecting means for detecting a frequency of fluid oscillation generated by the fluidic oscillating element, and a jet of the fluidic oscillating element. A fluidic gas shut-off device comprising: a width varying means for varying a nozzle width; and a jet width controlling means for automatically controlling a position of the width varying means based on a signal from the vibration detecting means.