JPH0674986B2 - Probable flow meter - Google Patents

Description

The present invention relates generally to fluid metering devices, and more particularly to
Concerning a speculative flow meter such as a turbine meter that converts the kinetic energy of a fluid such as gas supplied to a gas device through a pipeline to a rotary motion of a rotor and converts the rotation of the rotor into an electric signal to measure the flow rate of the fluid It is a thing.

[Conventional technology]

Conventionally, as a kind of turbine meter of this estimation type flow meter, there is one having a structure shown in FIG. In the figure, 1
Is a flow path portion that is connected to a midway of a pipe path (not shown) and forms a part of a flow path through which a fluid flows. At the center of the flow path portion 1, a pair of fixed and spaced apart in the longitudinal direction thereof is fixed. A support portion 2 is provided. The pair of supporting portions 2 is the flow path portion 1
The channel 1b is formed in cooperation with the inner wall 1a. Further, bearings 2a that rotatably support the rotating shaft 3a of the cap-shaped rotor 3 are provided at the facing portions of the pair of supporting portions 2.

On the outer periphery of the rotor 3, a blade 3b is provided which receives the kinetic energy of the fluid flowing in the flow path 1a and converts the kinetic energy of the fluid into the rotational movement of the rotor 3. The cap-shaped rotor 3
A magnet 4 is embedded in the bottom of the so as to rotate together with the rotor 3. Further, one of the pair of supporting portions 2 is provided with a magnetic detection element 5 such as a coil or a magnetoresistive effect (Hall effect) element at a portion facing the bottom of the rotor 3.

With the above configuration, when the fluid flows in from one end of the flow path portion 1 in the direction indicated by the arrow, the fluid flowing in the flow path 1b of the flow path portion 1 hits the plate 3 and the rotor 3 is rotated by the kinetic energy of the fluid. Like When the rotor 3 rotates, the magnet 4 embedded in the rotor 3 rotates together with it, so that the magnet 4 is repeatedly brought into contact with and separated from the magnetic detection element 5 provided on the support 2. As a result, the magnetic detection element 5 generates an electric signal according to the contact and separation of the magnet 4. The electric signal generated by the magnetic detection element 5 changes according to the rotation of the rotor 3, that is, the flow rate of the fluid flowing in the flow passage portion 1. By processing the electric signal, the flow passage portion 1 is processed.
It is possible to measure the flow rate of the fluid flowing to the.

[Problems to be Solved by the Invention]

As described above, in the case of the turbine meter, the rotation speed of the rotor changes according to load fluctuations, for example, changes in the gas usage of gas equipment, and the flow rate is measured by this change in rotation speed. When the volume load, for example, the movement of a gas appliance that consumes a large amount of gas is stopped, inertia causes the rotor to continue to rotate, and the rotation gradually decreases. Therefore, in the conventional estimation type flow meter that detects the rotation itself of the rotor as described above, the amount of rotation caused by inertia is also measured, and accurate measurement is difficult. This phenomenon is called over-metering, which was a major drawback of the speculative meter.

Further, in the above-described conventional flowmeter, since the magnet 4 embedded in the rotor 3 is used, the weight of the rotor increases and there is a problem in durability.

Therefore, the present invention eliminates the problem of overmetering and durability that make measurement inaccurate in the one that detects the rotation of the rotor and measures the flow rate, enables accurate metering, and achieves a long service life. The challenge is to provide a probabilistic flow meter.

[Means for Solving the Problems]

A probabilistic flowmeter made according to the present invention for solving the above-mentioned problems is provided in a fluid passage, and a rotor that receives and rotates the kinetic energy of the fluid flowing in the passage with a blade provided on the outer periphery, Separated in the moving direction of the blade by a distance corresponding to substantially the thickness of the blade, and when there is a blade between them, one is the pressure on the fluid inlet side of the flow passage, the other is the fluid outlet side of the flow passage. The pressure difference detecting means includes a pair of holes provided on the wall surface of the flow path so as to respectively receive pressure, and a differential pressure detecting means for generating an electric signal according to a pressure difference generated between the pair of holes. However, the rotor is rotated by the kinetic energy of the fluid flowing in the flow path, and a pulsed electric signal is generated due to a change in the pressure difference generated between the pair of holes each time the blade moves across the pair of holes. To No, it is characterized in that for measuring the flow rate of a fluid flowing in the flow channel based on the electrical signal.

[Action]

In the above configuration, the pair of holes provided apart from each other in the moving direction of the blade by a distance corresponding to substantially the thickness of the blade, when there is a blade between the two, one pressure on the fluid inlet side of the flow path, the other is Since each hole is provided on the wall surface of both passages so as to receive the pressure at the fluid inlet side and the pressure at the fluid outlet side when there is no blade between them, both holes are provided so as to receive the pressure at the fluid outlet side. Each time the rotor rotates due to the flow of fluid and the blade moves across the pair of holes, the pressure difference between both holes is approximately 0, the pressure difference between the fluid inlet side and the fluid outlet side is approximately 0, and so on. The differential pressure detecting means is adapted to generate a pulsed electric signal in response to the change.

Therefore, when the fluid is not flowing and there is no pressure difference between the fluid inlet side and the fluid outlet side, even if the blade may move across both holes, there will be no pressure difference between both holes. , No electric signal is generated, and the problem of overmetering does not occur. Therefore, it is possible to accurately measure the flow rate of the fluid flowing in the flow path based on the electric signal generated by the differential pressure detecting means, and since no member is provided in the rotor, an extra load is applied to the rotor. The durability is improved without hanging.

〔Example〕

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

FIG. 1 is a diagram showing an embodiment of a stochastic flowmeter according to the present invention, in which 11 is a fluid inlet 11a and a fluid outlet 1
1b is a flow path portion that forms a flow path for flowing a fluid. In the flow path portion 11, unillustrated pipes are connected to the fluid inlet 11a and the fluid outlet 11b, respectively. At the intermediate portion between the fluid inlet 11a and the fluid outlet 11b, a part of the flow passage portion 11 is bulged to one side to form a rotor housing portion 11c.
Inside the rotor housing portion 11c, a plurality of blades 12a are provided on the outer periphery.
The rotor 12 having the above is accommodated rotatably around the rotary shaft 12b, so that the bod 12a on the outer circumference of the rotor 12 faces the flow path between the fluid inlet 11a and the fluid outlet 11b.

While forming a flow path connecting the fluid inlet 11a and the fluid outlet 11b, the wall surface forming a part of the inner wall surface of the rotor housing portion 11c, the flow direction of the fluid, that is, the moving direction of the blade 12a of the rotor 12 In the pair of holes 13a and 1 which are separated by a distance corresponding to substantially the thickness of the blade 12a and are opened to the flow path side.
3b is formed. Between the pair of holes 13a and 13b, there is provided a vibration plate 14 which is displaced according to the pressure difference in these holes. The fluctuation plate 14 has a vibrating plate 14 in one hole 13a.
A differential pressure detection sensor having a condenser microphone configuration in which the diaphragm 14 is used as a movable electrode is formed together with the fixed electrode 15 provided so as to face with.

In the above configuration, when the fluid flows into the fluid inlet 11a of the flow path portion 11, the rotor 12 receives the kinetic energy of the inflowing fluid, that is, the pressure of the fluid at its blade 12a, and the rotor 12 rotates as indicated by the arrow in the figure. Rotating around 12b, the fluid is discharged from the fluid outlet 11b. In this way, the rotor 12 rotates, and one of the blades 12a thereof has the pair of holes 13a and 13a.
When it reaches between b, the upstream side of the blade 13a, that is, the hole
The fluid flows only into the 13a side, and the pressure inside the hole 13a becomes higher than the pressure inside the hole 13b. The pressure difference between the pair of holes 13a and 13b displaces the diaphragm 13 toward the hole 13b, and the diaphragm 14
Due to the displacement, the gap between the fixed electrode 15 and the vibrating plate 14 increases, and the electrostatic capacitance between the vibrating plate 13 and the fixed electrode 14 changes.

When the blade 12a located between the pair of holes 13a and 13b where the rotor 12 is further rotated moves over both the pair of holes 13a and 13b, the pressure in both holes 13a and 13b becomes equal and the vibration plate
14 returns to the original neutral position, and the capacitance between the diaphragm 14 and the fixed electrode 15 also returns to the original value.

The change in capacitance as described above is caused by the blade 12 of the rotor 12
Whenever a moves across a pair of holes 13a and 13b, the diaphragm 1
It is caused by the vibration of 4. The output of the differential pressure detection sensor is converted into an electric signal according to the change in the capacitance by, for example, a field effect transistor (FET),
For example, when the flow rate changes as shown in FIG. 2 (a), a pulsed electric signal as shown in FIG. 2 (b) is generated.

In addition, the negative component N of the electric signal shown in FIG.
This is caused by the fact that when 4 returns to the neutral position, it does not immediately stop at the neutral position but slightly swings to the opposite side.

Further, when the flow of the fluid is stopped, or when the flow rate is decreased as shown by the middle section X in FIG. 2 (a), the rotor 12
Continues to rotate. But in this case, the rotor 12
The blades 12a of the rotor 12 are simply rotated.
The pressure in the hole 13a on the upstream side becomes lower than the pressure in the hole 13b on the downstream side, and the output of the differential pressure detection sensor swings to the negative side as shown in the corresponding section of FIG. 2 (b). An electrical signal is generated. Therefore, the electric signal generated based on the flow of the fluid and the electric signal generated based on the idling can be clearly distinguished, and the occurrence of the measurement error due to the idling can be prevented.

Furthermore, even if the pressure of the fluid changes in the pipe, when the fluid is not flowing, the pressure in the pair of holes 13a and 13b only changes in the same phase, and the diaphragm 14 does not cause any displacement. The diaphragm 14 will not be erroneously detected due to pressure fluctuations.

Furthermore, in the above-mentioned embodiment, since the magnet is not used to detect the rotation of the rotor, the measurement is not affected by the influence of the external magnetic field.

In the embodiment described above, the rotor 12 is provided so that its rotation shaft 12b intersects in the direction of fluid flow.
The present invention is equally applicable to a so-called axial flow turbine meter using a rotor having a rotating shaft in the direction of fluid flow, as in the conventional example described above with reference to FIG.

FIG. 3 shows another embodiment of the inferring type flow meter according to the present invention configured as an axial flow turbine meter. The same parts as those described above with reference to FIG. The description is omitted.

In FIG. 3, a plurality of blades 3b on the outer circumference of the rotor 3
Is provided so as to be inclined by a predetermined angle with respect to the rotation shaft 3a so that the rotor 3 can be rotated by receiving the kinetic energy of the fluid flowing in the flow path. Then, on the wall surface 1a of the flow path portion 1, the tip end portion of the blade 3a when the rotor 3 rotates, is opened at a distance corresponding to the substantially thickness of the blade in the rotation direction of the rotor 3. A pair of holes
13a and 13b are formed. The openings of the pair of holes 13a and 13b are formed in a slit shape inclined by an angle corresponding to the inclination angle of the blade 3b.
This is effective in changing the pressure in a and 13b with high sensitivity according to the flow of fluid.

Further, in this embodiment, a pair of holes 13 are used as the differential pressure detection sensor.
A piezoelectric element 16 forming a partition wall between a and 13b is used. The piezoelectric element 16 generates a pulsed electric signal according to the flow rate by the same action as that of the embodiment of FIG. .

[Effect]

As described above, according to the present invention, the differential pressure detecting means generates an electric signal only when the rotor rotates in response to the flow of fluid, and when there is no flow of fluid, generates an electric signal even if the rotor rotates. Therefore, even if the large load is removed and the rotor spins, the problem of over-metering that misdetects this does not occur, and since the rotor is not equipped with any member Therefore, many effects can be obtained such that durability is improved without increasing the load and the life is extended.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the stochastic flow meter according to the present invention, and FIGS. 2 (a) and 2 (b) are waveform diagrams for explaining the operation of the stochastic flow meter of FIG. 3 (a) and 3 (b) are cross-sectional views showing different cross sections of another embodiment of the stochastic flow meter according to the present invention, and FIG. 4 is a cross-sectional view showing a conventional stoichiometric flow meter. 1,11 ...... Flow path part, 3,12 ...... Rotor, 3b, 12a ...... Blade, 13a, 13b ...... A pair of holes, 14 ...... Vibration plate, 15 ...... Fixed electrode, 16 ...... Piezoelectric element.

Claims (1)

[Claims] 1. A rotor provided in a fluid passage, which receives and rotates kinetic energy of the fluid flowing in the passage by a blade provided on the outer periphery, and a rotor which corresponds to a substantially thickness of the blade in a moving direction of the blade. Provided on the wall surface of the flow path so that when the blades are separated by a distance and there is a blade between them, one receives the pressure on the fluid inlet side of the flow path and the other receives the pressure on the fluid outlet side of the flow path. And a differential pressure detection means for generating an electric signal according to a pressure difference generated between the pair of holes, the differential pressure detection means, the kinetic energy of the fluid flowing in the flow path A rotor rotates, and a pulsed electric signal is generated by a change in a pressure difference generated between the pair of holes each time the blade moves across the pair of holes, and the flow path is generated based on the electric signal. Flowing into A speculative type flow meter characterized by measuring the flow rate of a fluid.