JP2002039832A - Flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easily replaceable flowmeter. SOLUTION: The inside of this flowmeter is previously filled with fluid to be used, the flowmeter can be used directly in replacement without requiring any replacement of the inner fluid. In this way, the flowmeter 1 can be replaced more easily and simply, and replacement workability can be greatly improved because the flowmeter 1 can be used directly without requiring any replacement of the fluid inside it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter for measuring a flow rate of a liquid, a gas or the like.

[0002]

2. Description of the Related Art Conventionally, a flow meter 1 of this type has a fluid inlet 3 having a fluid inlet 2 and a fluid outlet 5 having a fluid outlet 4, as shown in a sectional view of FIG. And a flow meter outer part 7 including them. Since the flow meter 1 has a space inside such as the fluid inflow section 3, the flow rate measurement section 6, and the fluid outflow section 5, the inside of the flow meter 1 is approximately 0.1 mm.
It had a volume of about 5 to 2 [L].

[0003]

As described above, since the conventional flowmeter 1 contains an unnecessary fluid such as air that is not suitable for use in the flowmeter, the flowmeter 1 is replaced with an old flowmeter. When a new flow meter is installed, it is necessary to discharge a fluid such as air filling the inside of the flow meter 1 through a piping system after the flow meter. In other words, if the use is immediately started while the fluid such as air unsuitable for use is left as it is, the gas table or the gas burner, such as a gas water heater, that was initially burning may cause the air mixed in the supply gas, etc. As a result, the combustion stops in the middle of the combustion, and as a result, a dangerous state may occur such as emission of unburned gas. For this reason, when the flow meter is replaced, waste such as discarding the gas remaining in the piping after the flow meter occurs, or considerable time is required to completely discharge the gas. There were times when it took time. For this reason, there was a problem that the efficiency of the flow meter replacement work was poor. In addition, if the flowmeter has a complicated internal structure, there is a problem that it takes a long time to completely discharge and replace the fluid such as air contained therein.

[0004]

A flow meter according to the present invention includes a fluid inlet, a flow measuring unit, and a fluid outlet, and fills a space from the fluid inlet to the fluid outlet with a fluid to be used. In addition, the fluid inlet and the fluid outlet have detachable stoppers to seal the fluid to be used. Therefore, even after the used flow meter is removed and a new flow meter is mounted, for example, a gas table or a gas water heater can be used. is there. In addition, since the fluid contained in the flow meter is the fluid to be used, it is not necessary to release the gas in the piping after the new flow meter, so that there is no waste and the efficiency of the flow meter replacement operation is improved.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A flow meter according to the present invention comprises a fluid inlet,
A flow measurement unit, comprising a fluid outlet, filling the space to be used from the fluid inlet to the fluid outlet with the fluid to be used, and having a removable stopper at the fluid inlet and the fluid outlet, The fluid to be used is sealed. For this reason, even immediately after replacement of the flow meter, there is no need to discharge the fluid inside the flow meter through the pipe, and the combustion apparatus can be used, and the efficiency of the replacement operation is improved.

Further, the flowmeter of the present invention is provided with a shielding portion between the fluid inlet and the fluid outlet, so that the filled fluid cannot be easily convected, so that it is not easily discharged to the outside. . For this reason, even if the stopper is removed, or
Even if the stopper is opened to replace the flow meter, the fluid to be used inside is not easily discharged. Therefore, even immediately after the replacement of the flow meter, there is no need to discharge the fluid inside the flow meter through the pipe, and the combustion equipment can be used, and the efficiency of the replacement operation is improved.

Further, the flow meter of the present invention has a structure provided with a fluid state detecting sensor for detecting the state of the filled fluid. For this reason, since the state of the fluid filled in the flow meter can be detected, the state of the filled fluid can be detected at any time, such as during storage of the flow meter, immediately before replacement, during replacement work, or immediately after replacement. Therefore, replacement work and the like can be performed with confidence.

Further, the flow meter of the present invention is provided with a notifying means for notifying the abnormality of the fluid when the state of the fluid is detected as abnormal. For this reason, when an abnormality occurs in the fluid, it can be notified to the outside by the notifying means constituted by the LCD, the light emitting diode, the buzzer or the like, which is safe.

In the flow meter according to the present invention, the fluid state detecting sensor is constituted by a pressure sensor. For this reason, when the fluid filled in the flow meter leaks, it can be detected, and it is possible to know a poor filling or the like. In addition, the presence or absence of leakage of the flow meter can be easily known, which is safe.

Further, in the flow meter according to the present invention, the fluid state detecting sensor is constituted by a fluid analyzing sensor for determining the type of the fluid. For this reason, since the type of fluid can be determined, if the type of fluid that has started to use is different from the type of fluid that has been filled, an abnormality can be detected and reported, and safety is ensured.

Further, the flow meter of the present invention is provided with a fluid type display means for displaying the type of the fluid. For this reason, the type of the fluid to be used can be known, and a flowmeter with a different type of fluid can be securely attached without being erroneously attached.

In the flow meter according to the present invention, the fluid analysis sensor is constituted by a thermal flow sensor. Therefore, the heat dissipation coefficient of the fluid can be known, and the type of the fluid can be easily determined. Therefore, when the type of the fluid to be used changes, it can be notified to the outside, and the safety is improved.

Further, in the flow meter according to the present invention, the fluid analysis sensor is constituted by an ultrasonic sensor. Therefore, the speed of sound propagating in the fluid can be easily measured, so that the type of the fluid can be determined. Therefore, when the type of the fluid to be used changes, it can be notified to the outside, and the safety is improved.

Further, in the flow meter according to the present invention, the flow measuring section is constituted by a thermal flow sensor. For this reason, flow measurement and fluid analysis can be shared, and an efficient flow meter can be configured.

Further, in the flow meter according to the present invention, the flow measuring section is constituted by a pair of ultrasonic sensors. For this reason, flow measurement and fluid analysis can be shared, and an efficient flow meter can be configured.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. It is to be noted that the same reference numerals in the drawings denote the same components, and a description thereof will be omitted.

FIG. 1 is a sectional view of a flow meter 1 according to a first embodiment of the present invention. Reference numeral 8 denotes a stopper provided on the fluid inlet 3 and reference numeral 9 denotes a stopper provided on the outlet 5. After these stopper plugs 8 and 9 are filled with the fluid to be used, LP gas, city gas, or the like at a predetermined pressure in the internal space of the fluid inflow portion 3, the fluid outflow portion 5, and the flow rate measurement portion 6, Attached. For this reason, the inside of the flow meter is filled with the fluid to be used, and when a new flow meter is installed in place of the old flow meter, it can be used without replacing the fluid inside the flow meter. can do.
Therefore, there is no need to exhaust the flow meter and the fluid after it, eliminating waste and improving the efficiency of the flow meter replacement work.

(Embodiment 2) FIG. 2 is a sectional view of a flow meter 1 according to Embodiment 2 of the present invention. 10 is a fluid inlet 3
Reference numeral 11 denotes a fluid shut-off valve which is provided in the fluid outflow portion 5 and which can be opened and closed freely. With such a configuration, even if the stopper 8 or 9 is opened for some reason, the fluid filled in the flowmeter 1 does not easily flow out to the outside. Therefore, the fluid filled in the flowmeter during storage or transportation is not lost.

Further, the fluid filled in the flow meter does not flow out to the outside during the mounting operation. Further, when installing a new flow meter in place of the old flow meter, the valves 10 and 11 which can be opened and closed after the installation work is completed.
By opening the flowmeter, an unsuitable fluid such as air is prevented from being mixed, and the fluid meter does not need to be replaced, and the flowmeter can be efficiently replaced.

In this embodiment, the openable and closable valves are attached to both the fluid inflow portion 3 and the fluid outflow portion 5. However, if only one of them is provided, the fluid inside the flow meter can be easily converted by convection. Cannot be moved to the whole inside of the flow meter, even if the stopper 8 or 9 is opened,
The fluid filled in the flow meter is not easily discharged outside in a short time. Accordingly, it is not necessary to quickly perform the flow meter replacement work, and the flow meter replacement work can be performed even by a non-skilled person.

(Embodiment 3) FIG. 3 is a sectional view of a flow meter 1 according to Embodiment 3 of the present invention. Reference numeral 12 denotes a state detection sensor that detects the state of the fluid. With such a configuration, when the state of the fluid filled in the flow meter changes, the change can be detected, so that the change of the fluid can be notified to the outside. Become. For example, the fluid state detection sensor may be a heat conduction sensor that detects the heat conduction of the fluid, a heat dissipation sensor that detects the degree of heat dissipation of the fluid, or an infrared sensor that detects the transmittance of infrared light, or a flammable fluid It can be constituted by a combustible gas sensor or the like for detecting the property. Therefore, an optimal fluid state detection sensor can be selected according to the properties of the fluid to be used and the properties of the fluid that is inappropriate for use such as air.

(Embodiment 4) FIG. 4 is an external view of a flow meter 1 according to Embodiment 4 of the present invention. Reference numeral 13 denotes a liquid crystal display panel provided on the outer surface 14 of the flowmeter main body. With this configuration, the result detected by the fluid state detection sensor that detects the state of the fluid inside the flow meter can be displayed. Accordingly, the state of the fluid to be used, which is filled in the flow meter, can be displayed, so that a wrong flow meter is not attached. The display unit may also be used as a display unit that displays the flow rate measured by the flow meter, the integrated flow rate, or the like.

Further, it may be constituted by a light emitting diode or a piezoelectric buzzer. In this case, the state of the fluid inside the flow meter is notified by the blinking state of the light emitting diode or the sounding state of the piezoelectric buzzer. Therefore, also in this case, since the state of the fluid inside the flow meter can be known,
Eliminates the need to install the wrong flow meter. By providing a switch on the exterior surface 14 and displaying or notifying in conjunction with the switch, power can be saved.

(Embodiment 5) FIG. 5 shows Embodiment 5 of the present invention.
1 shows a cross section of a flow meter 1 based on FIG. Reference numeral 15 denotes a pressure sensor provided inside the flow meter for detecting the pressure of the fluid. 1
Reference numeral 6 denotes a fluid pressure introducing unit to the pressure sensor. The pressure sensor 15 was constituted by a differential pressure sensor for detecting a differential pressure from the atmospheric pressure. With this configuration, it is possible to monitor the pressure of the fluid filling the inside of the flow meter. Therefore, the pressure of the filled fluid can be monitored both when the fluid to be used is filled and when the flow meter is replaced. That is, when the pressure of the fluid is higher than the atmospheric pressure, it can be determined that the fluid is sufficiently filled, so that it can be determined that the flow meter is normal and there is no leakage. For this reason, an abnormal or defective flowmeter is not attached by mistake.

Further, by adding a timer section and a storage section, it is possible to store the elapsed time from the time of filling and the degree of pressure drop at that time. In this case, for example, it is possible to easily know the leakage result one year later. Therefore, it is possible to easily know the state of leakage of the flow meter in the idle state, and to easily determine the quality of the flow meter. In addition, as a result, a defective flow meter may be erroneously attached, and safety is improved.

(Embodiment 6) FIG. 6 shows a cross section of a flow meter 1 based on Embodiment 6 of the present invention. Reference numeral 17 denotes a fluid composition analysis sensor provided inside the flow meter for analyzing a fluid composition. With this configuration, it is possible to detect the composition of the fluid inside the flow meter, and to detect when the pre-filled fluid, that is, the LP gas or the city gas changes to a fluid that is unsuitable for use such as air. Can be. Therefore, it is not necessary to mistakenly attach a flow meter filled with an unsuitable fluid.

(Embodiment 7) FIG. 7 shows an external view of a flow meter 1 based on Embodiment 7 of the present invention. Reference numeral 18 denotes a fluid type display unit provided on the exterior surface 14 of the flow meter main body and displaying a detection result of a fluid composition analysis sensor provided inside the flow meter for analyzing a fluid composition. With this configuration, it is possible to display the type of fluid filled in or inside the flow meter, and thus it is possible to display LP gas, city gas, or the like that has been filled in advance. Therefore, it is not necessary to erroneously mount a different type of flow meter filled with a fluid different from the fluid used. If a switch is provided on the exterior surface 14 and the display is performed in conjunction with the switch, power can be saved. The display unit 18
It may also be used as a display unit for displaying the flow rate measured by the flow rate measurement unit or the integrated flow rate.

(Embodiment 8) FIG. 8 shows an external view of a thermal flow sensor 19 provided in a flow meter 1 according to Embodiment 8 of the present invention and constituting a fluid composition analysis sensor. 20 is several mm
An insulating substrate such as glass having a corner thickness of several tens to several hundreds of microns is shown, 21 is a heating resistor, and 22 and 23 are temperature-sensitive resistors. In this configuration, a constant electric power is applied to the heating resistor 21 to generate heat, and the substrate 20 is heated. This temperature change is detected by the temperature-sensitive resistor 22 or 23.

For example, a temperature change when the fluid to be used is filled is stored, and when the filled fluid changes to air, a temperature change different from this temperature change is shown. For example, when the gas changes from city gas to air, the heat release to the fluid decreases, and the temperature change increases. Conversely, when the LP gas is changed to air, the heat release to the fluid increases, and the temperature change decreases. In this way, it is possible to easily detect a change in the composition of the fluid with a simple configuration. If a switch is provided outside and the composition of the fluid is detected only when it is desired to know the composition of the fluid in conjunction with the switch, a power saving configuration can be realized.

(Embodiment 9) FIG. 9 (a) shows a fluid composition analysis sensor section 24 provided in a part of the flow rate measuring section 6 in the flow meter 1 according to Embodiment 9 of the present invention. Several through-holes through which a filled fluid can freely enter and exit were provided in one boundary portion 25 of the fluid composition analysis sensor unit 24, and an ultrasonic sensor 26 was installed inside. FIG. 9B shows an ultrasonic sensor 2.
6 shows a sectional view. 27 is an acoustic matching layer, 28 is several millimeters ~
A piezoelectric body having a size of about 10 mm cubic, 29 is a can package, and 30 is a flange for fixing. When high-frequency power is applied to the piezoelectric body 28 of the ultrasonic sensor 26,
Ultrasonic waves are emitted from the surface of the acoustic matching layer 27. This ultrasonic wave propagates through the fluid at the speed of sound determined by the composition of the fluid.

Therefore, by detecting the sound speed of the ultrasonic wave, the composition of the fluid can be easily detected with a simple configuration. For example, when the fluid changes from LP gas to air, the sound speed of the ultrasonic wave becomes considerably slower, and it can be detected from the change. Further, when the air changes from the city gas to the air, the sound speed of the ultrasonic wave increases, so that it can be detected from the change. If a switch is provided outside and the composition of the fluid is detected only when it is desired to know the composition of the fluid in conjunction with the switch, a power saving configuration can be realized.

FIG. 10 shows the relationship between the type of gas measured using an ultrasonic sensor and the speed of sound. The horizontal axis indicates temperature, and indicates a range of −15 ° C. to + 50 ° C. where the flow meter normally operates. The vertical axis indicates the speed of sound. 31 is the sound speed of the ultrasonic wave propagating in the air, 32 is the sound speed of the ultrasonic wave propagating in the LP gas, 33
Indicates the speed of sound propagating in city gas. From this result, it can be seen that the temperature range where the flow meter is normally used (−15 ° C. to +
At 50 ° C.), the sound speed of each gas type does not overlap, so that the gas type can be easily detected and determined by detecting the sound speed.

(Embodiment 10) FIG. 11 is a diagram showing the principle of sound velocity measurement by an ultrasonic sensor 26 provided in a fluid composition analysis sensor section 24 inside a flow rate measurement section 6 based on Embodiment 10 of the present invention. . 26 indicates an ultrasonic sensor, 34 indicates a 45-degree reflecting plate for changing the direction of ultrasonic waves, and 35 indicates a reflecting plate for distance measurement. The arrows in the figure indicate the propagation paths of the ultrasonic waves. That is, the ultrasonic waves emitted from the ultrasonic sensor 26 are emitted vertically from the surface of the ultrasonic sensor,
The light propagates in the direction of the 45-degree reflecting plate 34. 45-degree reflector 34
The ultrasonic wave which has collided with is bent by 90 degrees and propagates in the direction of the reflecting plate 35 for distance measurement. Reflector 3 for distance measurement
The ultrasonic wave colliding with 5 is reflected and reaches the ultrasonic sensor 26 through the original path.

Therefore, if the length of the path through which the ultrasonic wave is known is known in advance, the propagation speed can be measured by measuring the time when the ultrasonic wave is transmitted and the time when the ultrasonic wave is received. With such a simple configuration, a single ultrasonic sensor can measure the speed of sound of ultrasonic waves propagating in gas. In this case, the configuration can be made without the 45-degree reflection plate. However, the reason for using the 45-degree reflection plate is that the configuration can be made more compact and can be built in the flow meter. Approximately 10
About 0 mm is sufficient.

(Embodiment 11) FIG. 12 is a diagram showing the principle of sound velocity measurement by an ultrasonic sensor inside a flow meter based on Embodiment 11 of the present invention. Different from the eleventh embodiment, the configuration is made using a pair of ultrasonic sensors. A pair of ultrasonic sensors 3
6, 37 were configured to face each other at a fixed distance (L). Assuming that the sound velocity in the fluid is Vs, the flow velocity of the fluid is Vf, the propagation time from the ultrasonic sensors 34 to 35 is Ta, and the propagation time from the ultrasonic sensors 35 to 34 is Tb, the propagation time of the ultrasonic waves and the sound velocity Is as follows.

Ta = L / (Vs + Vf), (36 → 37) Tb = L / (Vs−Vf), (37 → 36) Here, the flow velocity Vf of the fluid is transmitted from the ultrasonic sensor 36 to the ultrasonic sensor 37. Was defined as positive (+). Note that in the normal case, s >> Vf.

From this, Vs + Vf = Ta / L, Vs-Vf = Tb / L, therefore, 2 × Vs = (Ta / L) + (Tb / L) Vs = [(Ta / L) + (Tb / L) )] / 2 It can be seen that the sound velocity in the fluid, Vs, is obtained in this manner.

Here, the flow velocity Vf of the fluid does not enter the above equation for measuring the speed of sound, so that even if the fluid is flowing, the speed of sound of the ultrasonic wave propagating through the fluid can be measured. By using a pair of ultrasonic sensors, the speed of sound at which ultrasonic waves propagate can be measured even when a fluid is flowing inside the flow meter, and the gas type can be determined from the sound speed. In this case, since the gas type can be determined even when the fluid is flowing, even when the fluid is in use,
The type of fluid can be determined.

(Embodiment 12) FIG. 13A is a cross-sectional view of a flow meter according to Embodiment 12 of the present invention, in which a thermal type flow sensor 38 is provided in the flow rate measuring section 6. Thermal flow sensor (Fig. 8
Details are the same as those described in the eighth embodiment, and a description thereof will not be repeated. Reference numeral 39 denotes a calculation unit that calculates the flow velocity of the fluid measured by the thermal flow sensor 38 as a flow rate.
FIG. 13B shows an S-shaped characteristic 40 depending on the flow rate of the thermal flow sensor 38. The horizontal axis shows the flow velocity of the fluid flowing through the flow rate measuring unit, and the vertical axis shows the difference between the resistance values of the thermal resistors 22 and 23 and dR at that time. As shown in FIG. 13B, the difference between the resistance values of the thermal resistors 22 and 23 changes in an S-shape according to the positive and negative flow rates of the fluid.

For example, when the fluid is flowing in the direction of the heat-sensitive resistors 22 to 23 in FIG.
The heat generated in the step (2) moves toward the thermal resistor 23 due to the fluid, so that the temperature of the thermal resistor 23 is higher than that of the thermal resistor 22. In this case, FIG.
As shown in the figure, the resistance value of the heat-sensitive resistor 23 is larger than the resistance value of the heat-sensitive resistor 22. Conversely, when the fluid is flowing from the heat-sensitive resistors 23 to 22 in FIG. 8, the heat generated in the heat-generating resistor 21 moves toward the heat-sensitive resistor 22 by the fluid, so that the heat-sensitive resistor 2
2 has a higher temperature than the thermal resistor 23.

As a result, since the temperature of the thermal resistor 22 is higher than that of the thermal resistor 23, the resistance value of the thermal resistor 22 is larger than that of the thermal resistor 23. I have. Further, as a result, an S-shaped characteristic is obtained. By installing the thermal type flow sensor in the flow rate measuring unit in this way, the flow rate of the fluid can also be obtained.
Therefore, the composition of the fluid can be detected, and the flow velocity of the fluid can be measured.

(Embodiment 13) FIG. 14A is a cross-sectional view of a flow meter according to Embodiment 13 of the present invention, in which a pair of ultrasonic sensors 41 and 42 are provided in a flow measuring section 6. A pair of ultrasonic sensors were installed facing each other at a crossing angle of about 30 degrees and a distance L with respect to the direction in which the fluid flows (arrow 43). Assuming that the sound speed of the ultrasonic wave is Vs, the flow velocity of the fluid is Vf, and the intersection angle is θ, as described in the eleventh embodiment, the ultrasonic sensor 4
The propagation time Ta of the ultrasonic wave from 1 to 42 and the propagation time Tb of the ultrasonic wave from the ultrasonic sensors 42 to 41 are as follows.

Ta = L / [Vs + Vf × COS
(Θ)], (41 → 42) Tb = L / [Vs−Vf × COS (θ)], (42 → 4
1) From this, Vs + Vf × COS (θ) = L / Ta, Vs−Vf × COS (θ) = L / Tb, Therefore, Vs = [(L / Ta) + (L / Tb)] / 2, Vf = [(L / Ta)-(L / Tb)] / [2 × COS
(Θ)].

From this, it can be seen that both the propagation speed, Vs, at which the ultrasonic wave propagates in the fluid, and the flow velocity, Vf, of the fluid can be measured. Therefore, by installing a pair of ultrasonic sensors at a certain intersection angle (θ) in a place where the fluid flows, even if the fluid is flowing, the ultrasonic wave propagates through the fluid even if the fluid is flowing. Can be measured, the type of fluid can be determined, and the flow velocity and Vf of the fluid can also be measured. FIG. 14 (b)
The relationship between the flow velocity Vf of the fluid measured as described above and the propagation time difference of the ultrasonic wave is shown below. As shown by the characteristic line 44, it can be seen that the propagation time of the ultrasonic wave follows well in response to the flow velocity change in a wide range.

Therefore, it is understood that by installing one ultrasonic sensor and measuring the difference in the propagation assist time, it is possible to measure a change in the flow velocity over a wide range and measure the flow rate. As described above, when one ultrasonic sensor is used to constitute the fluid composition analysis sensor, the flow velocity of the fluid can also be measured, so that the configuration can be made compact.

[0046]

As is apparent from the above description, the following effects can be obtained according to the ultrasonic flowmeter of the present invention.

(1) Since the fluid to be used has already been filled, the replacement of the flow meter can be performed efficiently and without waste.

(2) Since the fluid shielding portion is provided, the filled fluid does not easily escape, so that the replacement operation can be performed efficiently.

(3) Since the sensor for detecting the state of the fluid is provided, the state of the filled fluid can be confirmed at the time of replacing the flow meter.

(4) When an abnormality occurs in the filled fluid, the abnormality can be known from the outside, so that the safety is improved.

(5) Since the pressure sensor is provided, it is possible to detect when the filled fluid leaks, so that the flow meter is not erroneously attached.

(6) Since a discrimination sensor for discriminating the type of the filled fluid is provided, it is possible to detect when the type of the filled fluid changes and thus it is safe.

(7) Since a fluid type indicator is provided, it is not necessary to attach a different flow meter by mistake.
It is safe.

(8) Since the fluid analysis sensor is constituted by a thermal flow sensor, the type of the fluid can be easily determined from the heat radiation characteristics of the fluid with a simple configuration.

(9) Since the fluid analysis sensor is constituted by an ultrasonic sensor, the velocity of the ultrasonic wave propagating in the fluid is
The type of the fluid can be determined by discrimination.

(10) The configuration is simplified because it is configured with one ultrasonic sensor.

(11) Since one ultrasonic sensor is used, it is possible to measure the propagation speed of ultrasonic waves when the fluid flows.

(12) Since the flow rate measuring section is constituted by a thermal type flow sensor, the type of the fluid can be determined and the flow rate can be measured at the same time, and the configuration becomes compact.

(13) Since the flow rate measuring unit is constituted by a pair of ultrasonic sensors, it is possible to use both the type determination of the fluid and the flow rate measurement.

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow meter according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a flow meter according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a flow meter according to a third embodiment of the present invention.

FIG. 4 is an external view of a flow meter according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a flow meter according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a flow meter according to a sixth embodiment of the present invention.

FIG. 7 is an external view of a flow meter according to a seventh embodiment of the present invention.

FIG. 8 is an external view of a thermal flow sensor according to an eighth embodiment of the present invention.

9A is a sectional view of a flow meter according to a ninth embodiment of the present invention. FIG. 9B is a sectional view of an ultrasonic sensor according to a ninth embodiment of the present invention.

FIG. 10 is a characteristic diagram of an ultrasonic sensor according to a ninth embodiment of the present invention.

FIG. 11 is a view for explaining the principle of sound velocity measurement in Embodiment 10 of the present invention.

FIG. 12 is a view for explaining the principle of sound velocity measurement in Embodiment 11 of the present invention.

13A is a cross-sectional view of a flow meter according to Embodiment 12 of the present invention. FIG. 13B is a characteristic diagram of a thermal flow sensor according to Embodiment 12 of the present invention.

14A is a sectional view of a flow meter according to Embodiment 13 of the present invention. FIG. 14B is a characteristic diagram of an ultrasonic sensor according to Embodiment 13 of the present invention.

FIG. 15 is a sectional view of a conventional flow meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow meter 2 Fluid inflow 3 Fluid inflow part 4 Fluid outflow 5 Fluid outflow part 6 Flow rate measurement part 8, 9 Stopper 10, 11 Shutoff valve 12 State detection sensor 13 Liquid crystal display board 15 Pressure sensor 16 Pressure introduction part 17 Composition Analysis sensor 19 Thermal flow sensor 21 Heating resistor 24 Fluid composition analysis sensor unit 26, 41, 42 Ultrasonic sensor 28 Piezoelectric body

Claims (13)

[Claims] 1. A fluid inlet, a flow measuring unit, and a fluid outlet are provided. A space from the fluid inlet to the fluid outlet is filled with a fluid to be used, and the fluid inlet and the fluid outlet are filled in the space. A flow meter having a removable stopper and sealing the fluid to be used. 2. The flow meter according to claim 1, further comprising a shielding portion between the fluid inlet and the fluid outlet so that the filled fluid is not easily discharged to the outside. 3. The flow meter according to claim 1, further comprising a fluid state detection sensor for detecting a state of the filled fluid. 4. The flowmeter according to claim 3, further comprising a notifying unit for notifying the abnormality of the fluid when the state of the fluid is detected as abnormal. 5. The flow meter according to claim 3, wherein the fluid state detection sensor comprises a pressure sensor. 6. The flow meter according to claim 3, wherein the fluid state detection sensor is constituted by a fluid analysis sensor for determining the type of the fluid. 7. The flow meter according to claim 6, further comprising a fluid type display means for displaying the type of the fluid. 8. The flow meter according to claim 6, wherein the fluid analysis sensor comprises a thermal flow sensor. 9. The flow meter according to claim 6, wherein the fluid analysis sensor comprises an ultrasonic sensor. 10. The flow meter according to claim 9, wherein the fluid analysis sensor comprises a single ultrasonic sensor. 11. The flow meter according to claim 9, wherein the fluid analysis sensor comprises a pair of ultrasonic sensors. 12. The flow meter according to claim 1, wherein the flow rate measuring section is constituted by a thermal flow sensor. 13. The flowmeter according to claim 1, wherein the flow rate measuring unit comprises a pair of ultrasonic sensors.