JPH08159828A - Fluid vibration detection sensor and fluidic flow meter using it - Google Patents

Abstract

PURPOSE: To provide a fluid vibration detection sensor which can detect fluid vibration without utilizing the piezoelectric characteristic of a polymer piezoelectric film, and can prevent the corrosion of a vibration film. CONSTITUTION: The fluid vibration detection sensor is provided with a fluid vibration detection means 40A, 40B composed of an electromagnetic coil 4 and a magnet 42. The electromagnetic coil 41 is arranged in the center portion 35b of a vibration film 35. The magnet 42 is fixedly arranged on the internal vessel 32 side so that its one part is inserted into the electromagnetic coil 41. When the vibration film 35 vibrates based on a differential pressure, the magnet 42 relatively reciprocates in the electromagnetic coil 41. As the result, induction current is generated in the electromagnetic coil 41 by electromagnetic induction. Fluid vibration flowing in a passage can be detected based on this current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid vibration detection sensor for detecting fluid vibration of a fluid based on a difference in pressure difference between two pressure chambers, and a fluidic flowmeter using the same.

[0002]

2. Description of the Related Art Conventionally, as this type of fluid vibration detecting sensor, there is known a sensor which is applied to a fluidic flow meter and detects fluid vibration of a fluid which alternately flows through a pair of feedback channels. This fluid vibration detection sensor has two pressure chambers partitioned by a polymer piezoelectric film,
The pressure of the fluid flowing through one feedback channel is introduced into one pressure chamber, and the pressure of the fluid flowing through the other feedback channel is introduced into the other pressure chamber. In this fluid vibration detection sensor, the fluid vibration can be detected by utilizing the piezoelectricity of the polymer piezoelectric film to detect the fluctuation in the differential pressure between the two pressure chambers.

[0003]

However, in the conventional fluid vibration detection sensor, since metal films serving as electrodes are formed on the entire surfaces of both surfaces of the polymer piezoelectric film for detecting the differential pressure, this metal film is used. May be corroded by water contained in gas, oil mist, etc. after long-term use. Therefore, there is a problem that fluid vibration may be erroneously detected, resulting in a decrease in detection accuracy.

The present invention has been made in view of the above problems, and an object thereof is to prevent erroneous detection of fluid vibration caused by corrosion of a metal film due to moisture, oil mist, or the like, and improve fluid detection accuracy. It is to provide a detection sensor and a fluidic flowmeter using the detection sensor.

[0005]

According to another aspect of the present invention, there is provided a fluid vibration detecting sensor having a first pressure chamber and a second pressure chamber, and a pressure variation detecting section into which a pressure variation corresponding to fluid vibration is introduced. And a partition formed between a corrosion resistant insulating material and between the first pressure chamber and the second pressure chamber in the pressure fluctuation detection unit to prevent pressure fluctuations introduced into the pressure fluctuation detection unit. Based on the vibrating membrane vibrating due to the fluctuation of the differential pressure between the two pressure chambers and the vibration state of the vibrating membrane is converted into the fluctuation of the magnetic field, and by detecting the magnetic field fluctuation, an electric signal according to the fluid vibration is generated. And a fluid vibration detecting means for outputting.

In this fluid vibration detecting sensor, the differential pressure between the two pressure chambers of the pressure variation detecting section fluctuates based on the fluid vibration, and the vibrating membrane vibrates due to this differential pressure fluctuation. The fluid vibration detecting means converts the vibration state of the vibrating film into a fluctuation of the magnetic field and outputs an electric signal (induced current) according to the fluid vibration based on the fluctuation of the magnetic field. Therefore, it is not necessary to use the piezoelectric film having the metal film formed on the surface as the vibrating film, and the vibrating film can be formed of a corrosion-resistant insulating material. Therefore, there is no risk of corrosion due to gas in the fluid, oil mist, etc., and fluid vibration will not be erroneously detected.

According to a second aspect of the present invention, there is provided a fluid vibration detecting sensor according to the first aspect, wherein the fluid vibration detecting means is
An electromagnetic induction coil disposed at either a predetermined position in the pressure chamber or a predetermined position on the surface of the vibrating membrane, and a predetermined position in the pressure chamber or a predetermined position on the surface of the vibrating membrane. Or a magnet that is disposed on the other side and that relatively reciprocates in the electromagnetic induction coil according to the vibration state of the vibrating membrane. In this fluid vibration detection sensor, the magnet relatively reciprocates in the electromagnetic induction coil as the vibrating membrane vibrates, and thereby an induction current corresponding to the fluid vibration is generated in the electromagnetic induction coil.

According to a third aspect of the present invention, there is provided a fluid vibration detecting sensor according to the first or second aspect, wherein the pressure based on the fluid vibration of one of the two flow passages through which the fluid flows alternately is applied to the first flow passage. And a pressure based on fluid vibration of the other flow passage are introduced into the second pressure chamber, and fluid vibration of the fluid alternately flowing through the two flow passages is detected. is there. In this fluid vibration detection sensor, the vibrating membrane vibrates due to the difference in pressure difference between the fluid pressure in one flow passage and the fluid pressure in the other flow passage, and the fluid vibration detection means outputs an electrical signal according to the vibration state. To be done.

A fluid vibration detecting sensor according to a fourth aspect of the present invention is the fluid vibration detecting sensor according to the third aspect, further comprising a pair of pressure fluctuation detecting portions, wherein the vibrating membranes of the pressure fluctuation detecting portions are arranged in parallel with each other. The positional relationship between the first pressure chamber and the second pressure chamber with respect to the vibrating membrane is set to be opposite to each other, and the pressure based on the fluid vibration of one of the two flow paths in which the fluid alternately flows is set. , So as to be introduced into the first pressure chamber of each of the two pressure fluctuation detecting units, and to introduce pressure based on the fluid vibration of the other flow path into the second pressure chamber of each of the two pressure fluctuation detecting units. It is composed. In this fluid vibration detection sensor, by comparing the phases of two electric signals (AC signals) output from the two pressure fluctuation detection units, it is possible to distinguish whether the fluctuation of the differential pressure is based on the fluid vibration. It becomes possible to do.

According to a fifth aspect of the fluid vibration detecting sensor of the present invention, an inlet portion for receiving the fluid, a nozzle portion for allowing the fluid received from the inlet portion to generate a jet flow, and a nozzle portion for receiving the fluid passing through the nozzle portion. 5. A fluid vibration detection sensor according to any one of claims 1 to 4, wherein a pair of feedback flow paths that lead to the jet outlet side of the fluid and a fluid that alternately flows through the pair of feedback flow paths are introduced to detect fluid vibration. Flow rate calculating means for calculating the flow rate of the fluid received from the inlet portion based on the fluid vibration detected by the fluid vibration detecting sensor.

In this fluidic flow meter, the fluid received from the inlet part passes through the nozzle part and becomes a jet flow, and this jet flow alternately flows through the pair of feedback flow paths. The fluid vibration of the fluid alternately flowing through the pair of feedback flow paths is detected by the fluid vibration detection sensor according to any one of claims 1 to 4. Further, the flow rate of the fluid received from the inlet portion is calculated based on the detected fluid vibration.

[0012]

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

FIG. 1 shows a schematic structure of a fluidic flow meter according to an embodiment of the present invention. This fluidic flowmeter detects fluid vibration of a fluid alternately flowing through a pair of feedback flow paths 21 and 22 formed inside the flowmeter main body 10 by a fluid vibration detection sensor 30, and this fluid vibration causes a fluid vibration. The flow rate calculator 60 calculates the flow rate of the fluid based on the correlation with the flow rate.

FIG. 2 shows a sectional structure of the flowmeter main body 10 according to this embodiment. The flowmeter main body 10 has an inlet 11 for receiving a fluid and an outlet 12 for discharging the fluid. A fluid flow path 13 is formed in the flowmeter body 10 between the inlet portion 11 and the outlet portion 12. In the fluid passage 13, there is provided a nozzle portion 14 for passing the fluid received from the inlet portion 11 to generate a jet flow. On the downstream side of the nozzle portion 14, a pair of side walls 16 and 17 forming an enlarged flow path are provided. A target 18 is provided on the upstream side and a target 19 is provided on the downstream side with a predetermined space between the side walls 16 and 17. A pair of feedback channels 21 and 22 are formed outside the side walls 16 and 17 to return the fluid that has passed through the nozzle portion 14 to the ejection port side of the nozzle portion 14 along the outer peripheral portions of the side walls 16 and 17. Guide 2
3 are provided. The return guide 2 is provided between each outlet portion of the feedback flow paths 21 and 22 and the outlet portion 12.
By the rear surface of 3 and the flowmeter main body 10, a pair of discharge paths 2
4, 25 are formed. Pressure guiding holes 26 and 27 are provided in the vicinity of the ejection port of the nozzle portion 14 so as to correspond to the feedback flow paths 21 and 22. These pressure guiding holes 26, 27
Is communicated with a fluid vibration detection sensor 30 (see FIG. 3) described later.

FIG. 3 shows a sectional structure of the fluid vibration detecting sensor 30 according to this embodiment. The fluid vibration detection sensor 30 includes an airtight container 31, and the inner space of the airtight container 31 is divided into two pressure fluctuation detection units 3 by an inner container 32.
It is divided into 3,34. The middle container 32 is made of insulating synthetic resin. Medium container 32 and closed container 31
A seal member (O-ring) (not shown) is provided between and to secure the airtightness of each of the pressure fluctuation detection units 33 and 34.

The pressure fluctuation detecting section 33 includes a pressure chamber 33A as a first pressure chamber and a pressure chamber 33 as a second pressure chamber.
B is provided, and the pressure chambers 33A and 33B are partitioned by a vibrating film 35. Similarly, the pressure fluctuation detection unit 34 has a pressure chamber 34A as a first pressure chamber and a pressure chamber 34B as a second pressure chamber, and the vibrating membrane 35 separates these pressure chambers 34A and 34B. Has been. The vibrating membrane 35 forms a partition between the two pressure chambers, and vibrates due to the fluctuation of the differential pressure between the two pressure chambers based on the pressure fluctuations introduced into the pressure fluctuation detection units 33 and 34, and has elasticity. It is made of a corrosion-resistant insulating material. Specifically, for example, a polymer film such as a polyvinylidene fluoride (PVDF) film that has not been subjected to poling treatment is used.

The vibrating membrane 35 has its peripheral portion 35a held from both sides by a cylindrical supporting member 36 arranged along the inner peripheral surface of each of the pressure fluctuation detecting portions 33, 34.
It is in a state of being stretched between the pressure chambers 33A and 33B and between the pressure chambers 34A and 34B. A not-shown seal member (O ring) is arranged between the vibrating membrane 35 and the support member 36, and between the pressure chamber 33A and the pressure chamber 33B and between the pressure chamber 34A and the pressure chamber 34B. Each is airtight.

The pressure chamber 33A of the pressure fluctuation detection unit 33 and the pressure chamber 34A of the pressure fluctuation detection unit 33 are respectively contained in the middle container 3.
2 through the pressure guiding hole 32A formed in the closed container 31 and the pressure guiding hole 31A formed in the closed container 31 to communicate with the pressure guiding hole 26 formed in the one feedback flow path 21 of the flowmeter main body 10 to provide feedback. A pressure corresponding to the flow rate of the fluid flowing through the flow path 21 is introduced.

The pressure chamber 33B of the pressure fluctuation detection unit 33 and the pressure chamber 34B of the pressure fluctuation detection unit 33 are respectively contained in the middle container 3.
2 through the pressure guide hole 32B formed in the closed container 31 and the pressure guide hole 27 formed in the other feedback flow path 22 of the flowmeter main body 10 through the pressure guide hole 31B formed in the closed container 31. The pressure corresponding to the flow rate of the fluid flowing through the feedback channel 22 is introduced. That is, the pair of feedback channels 2
Due to the fluid fluctuations of the fluids alternately flowing through 1 and 22, the differential pressure between the pressure chamber 33A and the pressure chamber 33B in the pressure varying portion 33 and the differential pressure between the pressure chamber 34A and the pressure chamber 34B in the pressure varying portion 33 vary. As a result, the vibrating film 35 vibrates around the central portion 35b.

The pressure fluctuation detectors 33 and 34 have the same size, and the vibrating membranes 35 are arranged in parallel with each other, so that the pressure of the fluid flowing through one of the feedback channels 21 is simultaneously introduced. Pressure chamber 33A and pressure chamber 34A
Are set so that the vertical positions of the vibrating film 35 are opposite to each other. That is, in the present embodiment, the pressure chamber 33A is above the vibrating membrane 35, and the pressure chamber 34A is
A is set at a position below the vibrating membrane 35. Further, the relationship between the pressure chamber 33B and the pressure chamber 34B into which the pressure of the fluid flowing through the other feedback channel 22 is simultaneously introduced with respect to the vibrating membrane 35 is also the pressure chamber 33A and the pressure chamber 34A.
It is similar to the relationship with. In this way, the pressure chamber 33
Positional relationship between A and 34A, and pressure chambers 33B and 34
The positional relationship between the Bs is made different from each other with respect to the vibrating membrane 35, depending on whether the vibration of the vibrating membrane 35 is due to fluid vibration, as described later, or due to another cause (for example, vibration mechanically applied from the outside). This is to distinguish whether or not.

In the pressure chamber 33A on the pressure fluctuation detecting section 33 side, the vibration state of the vibrating membrane 35 is converted into a fluctuation of the magnetic field, and an electric signal corresponding to the fluid vibration is output by detecting the fluctuation of the magnetic field. A fluid vibration detecting means 40A is provided. The fluid vibration detecting means 40A is composed of an electromagnetic induction coil 41 and a magnet 42. The electromagnetic induction coil 41 is provided in the central portion 3 of the surface of the vibrating membrane 35 on the pressure chamber 33A side.
It is arranged for 5b. This electromagnetic induction coil 41
Is a cylindrical plastic substrate 43 as shown in FIG.
A wiring layer 4 made of a metal such as aluminum (Al)
4 is formed by spirally depositing 4. One end surface of the plastic substrate 43 is fixed to the surface of the vibrating film 35. The surface of the electromagnetic induction coil 41 is covered with a coating film 45. Both ends of the electromagnetic induction coil 41 are connected to the output terminals 46,
It is taken out as 47. One output terminal 46 is via a wiring layer 48 formed on the surface of the vibrating film 35, and the other output terminal 47 is via a wiring layer 49 also formed on the surface of the vibrating film 35. Connected to 50.

The magnet 42 is fixedly arranged in the inner container 32 via a support member 48 arranged on the ceiling surface of the pressure chamber 33A,
A part is inserted in the internal space of the electromagnetic induction coil 41. The magnet 42 may be a permanent magnet or an electromagnet.

A fluid vibration detecting means 40B having the same structure as the fluid vibration detecting means 40A in the pressure chamber 33A is also provided in the pressure chamber 34B on the pressure fluctuation detecting portion 34 side.

In the closed container 31, there is provided a space 31C partitioned by the middle container 32. Space part 31C
A circuit board 50 for detecting the electric signal (AC signal) output from the fluid vibration detecting means 40A, 40B is disposed therein. The circuit board 50 is fixed to the inner container 32 by a lead screw 51.

FIG. 5 shows a specific circuit configuration of the circuit board 50. The circuit board 50 includes amplification circuits 55A and 55B for amplifying the AC signals output from the output terminals 46 and 47 of the electromagnetic induction coils 41 of the pressure fluctuation detection units 33 and 34, and the amplification circuits 55A and 55B.
AC current detection circuits 52A and 52B for detecting the amplified signals respectively output from B and whether the current generated in the electromagnetic induction coil 41 in response to the detection signals of these AC current detection circuits 52A and 52B is due to fluid vibration. Alternatively, the comparison / determination circuit 5 which determines whether the cause is another cause (for example, vibration mechanically applied from the outside) and outputs the determination signal.
3 and the determination signal of fluid vibration from the comparison determination circuit 53 are input, the AC current detection circuit 52A,
An arithmetic circuit 54 for calculating the frequency of fluid vibration (that is, the switching frequency at which the fluid alternately flows through the pair of feedback channels 21 and 22; also referred to as the fluidic oscillation frequency) based on the output of each 52B. ing.

The output end of the arithmetic circuit 54 is connected to the input end of the flow rate calculation unit 60 shown in FIG. 1, and outputs the calculated frequency signal to the flow rate calculation unit 60.

Next, the operation of the fluidic flow meter according to this embodiment will be described.

First, when the fluidic flowmeter does not receive the fluid, the fluid does not flow through the pair of feedback flow paths 21 and 22 of the flowmeter body 10, and the pressure chamber 33A of the fluid vibration detecting sensor 30 is 34A and pressure chamber 33
The room pressures of B and 34B do not change. Therefore, in this state, as shown in FIG. 3, the vibrating membrane 35 is not displaced in any direction and maintains the equilibrium state.

When the fluidic flowmeter receives the fluid, the fluid received from the inlet portion 11 of the flowmeter main body 10 enters the nozzle portion 14 through the fluid flow path 13. The fluid that has passed through the nozzle portion 14 becomes a jet stream and is jetted from the jet outlet 14. The fluid ejected from the ejection port 14 alternately flows through the pair of feedback channels 21 and 22.

Here, when the fluid starts to flow in one of the feedback flow paths 21 (hereinafter, referred to as a flow rate increasing state), the pressure chamber 33A of the pressure fluctuation detection unit 33 and the pressure chamber 34A of the pressure fluctuation detection unit 34 respectively. Is lower than in steady state. On the other hand, the pressure chamber 3 of the pressure fluctuation detection unit 33
The room pressures of 3B and the pressure chambers 34B of the pressure fluctuation detection unit 34 are the same as those in the steady state. Therefore, due to the pressure difference, in the pressure fluctuation detection units 33 and 34, as shown in FIG.
It is displaced toward the A side.

With the displacement of the vibrating film 35, the electromagnetic induction coil 41 arranged therein also moves, and an induction current is generated in the electromagnetic induction coil 41 in accordance with the moving speed.
Here, as shown in FIG. 6, the electromagnetic induction coil 41 on the pressure fluctuation detection unit 33 side moves in a direction approaching the magnet 42, and the electromagnetic induction coil 41 on the pressure fluctuation detection unit 34 side moves away from the magnet 42. Since they move in the same direction, the currents generated in the electromagnetic induction coils 41 of the pressure fluctuation detecting units 33 and 34 are in opposite directions.

When the flow rate of the fluid flowing through one of the feedback flow paths 21 starts to decrease from the flow rate increasing state (hereinafter referred to as the flow rate decreasing state), the room pressures of the pressure chambers 33A and 34A become higher than when the flow rate increases. Also in this case, since the room pressures of the pressure chambers 33B and 34B are the same as those in the steady state, each vibrating membrane 35 is displaced toward the horizontal position in the steady state. At this time, currents are generated in the electromagnetic induction coil 41 in the opposite directions to those in the flow rate increasing state.

On the contrary, when the fluid starts to flow in the other feedback flow path 22, the pressure fluctuation detecting section 33 corresponding to this starts.
The inner pressures of the pressure chamber 33B on the side and the pressure chamber 34B on the side of the pressure fluctuation detection unit 34 become lower than in the steady state. On the other hand, since the chamber pressures of the pressure chambers 33A and 34A are the same as those in the steady state, the central portion 35b of each vibrating membrane 35 is located on the pressure chambers 33B and 34B side, contrary to the case shown in FIG. Displace each toward. At this time, a current is generated in the electromagnetic induction coil 41 in a direction opposite to the flow rate increasing state of the one feedback flow channel 21 (that is, in the same direction as the flow rate reducing state of the one feedback flow channel 21).

The current (AC current) generated in the electromagnetic induction coil 41 of the pressure fluctuation detecting section 33 in this way is amplified by the amplifier circuit 5.
After being amplified to a predetermined size by 5A, it is detected by the AC current detection circuit 52A. Similarly, the current generated in the electromagnetic induction coil 41 of the pressure fluctuation detection unit 34 is amplified by the amplification circuit 55B to a predetermined size and then detected by the AC current detection circuit 52B. Then, the currents detected by the alternating current detection circuits 52A and 52B are output to the comparison / determination circuit 53 and the arithmetic circuit 54, respectively.

In this embodiment, the pressure chambers 33A and 34A
A and A and the pressure chambers 33B and 34B are set such that the vertical positional relationship with respect to the vibrating film 35 is reversed.
Further, since one fluid vibration detecting means 40A is provided in the pressure chamber 33A as the first pressure chamber, and the other fluid vibration detecting means 40B is provided in the pressure chamber 34B as the second pressure chamber. The electromagnetic induction coils 41 of the fluid vibration detecting means 40A and 40B move in opposite directions in response to the fluid vibration. Therefore, the direction of the current generated in the electromagnetic induction coil 41 is determined by the pressure fluctuation detecting unit 33 and the pressure fluctuation detecting unit 3.
The numbers 4 and 4 are opposite to each other. That is, the AC signals detected by the AC current detection circuits 52A and 52B have the same cycle, but have opposite phases to each other. On the other hand, for example, when it is affected by vibration from the outside,
The vibrating membranes 35 of the pressure fluctuation detection units 33 and 34 are both displaced in the same direction, and the respective electromagnetic induction coils 41 also move in the same direction. Therefore, the direction of the current generated in the electromagnetic induction coil 41 is the same in the pressure fluctuation detection unit 33 and the pressure fluctuation detection unit 34. That is, the alternating current detection circuits 52A and 52B
The AC signals detected by have the same period and the same phase.

Therefore, the comparison / judgment circuit 53 compares the phases of the outputs of the AC current detection circuit 52A and the AC current detection circuit 52B, and if they are in opposite phases, judges that they are due to fluid vibration,
If they are in the same phase, we judge that they are due to external influences,
The determination signal is output to the arithmetic circuit 54.

When the comparison circuit 53 receives a determination signal indicating fluid vibration, the arithmetic circuit 54 receives the fluid flowing through the pair of feedback channels 21 and 22 based on the outputs of the alternating current detection circuits 52A and 52B. The fluid vibration frequency (ie, fluidic oscillation frequency) is calculated and output to the flow rate calculation unit 60. The flow rate calculation unit 60 determines the flow rate of the fluid from the frequency of the fluid vibration input from the calculation circuit 54 based on the fact that the fluid vibration of the fluid flowing through the pair of feedback flow paths 21 and 22 has a correlation with the flow rate of the fluid. Calculate

As described above, in this embodiment, the vibration state of the vibrating film 35 due to the fluctuation of the differential pressure is detected by the fluid vibration detecting means 40A, 40A constituted by the electromagnetic induction coil 41 and the magnet 42.
Since the current is detected by B and the current corresponding to the fluid vibration is generated using electromagnetic induction, the vibration film 35 is
The fluid vibration can be detected without using a piezoelectric film having a metal film formed on the surface as an electrode. Therefore,
The vibrating film 35 can be formed of a corrosion-resistant insulating material, so that erroneous detection due to corrosion is eliminated and detection accuracy is significantly improved.

Further, in the present embodiment, a pair of pressure fluctuation detecting units 33 and 34 are provided and the pressure fluctuation detecting unit 3 is provided.
Pressure chamber 33A as the first pressure chamber in 3, 34,
34A, and pressure chambers 33B as second pressure chambers,
34B are set so that the positional relationship is opposite to each other with respect to the vibrating membrane 35, and one fluid vibration detecting means 40A
Is provided in the pressure chamber 33A as the first pressure chamber, and the other fluid vibration detecting means 40B is provided in the pressure chamber 34B as the second pressure chamber. Therefore, the vibration directions of the vibrating membranes 35 of the pressure fluctuation detecting unit 33 and the pressure fluctuation detecting unit 34 are
The fluid vibration and the other causes may be different from each other. As a result, the AC current is detected by comparing the vibration directions of the two vibrating membranes 35 (that is, determining whether the two electric signals output from the pressure fluctuation detection units 33 and 34 are in the opposite phase or the same phase). It is possible to distinguish whether the current detected by the circuits 52A and 52B is due to fluid vibration.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, the electromagnetic induction coil 41 is arranged on the vibrating membrane 35 side and the magnet 42 is fixed on the inner container 32 side.
The electromagnetic induction coil 41 is fixed to the inner container 32 side, and the magnet 42
May be disposed on the vibrating membrane 35 side. Further, although the fluid vibration detecting means is provided only in the pressure chamber 33A and the pressure chamber 14B, the pressure chambers 33A, 33B and 34 are provided.
It may be provided in each of A and 34B.

Further, in the above embodiment, the pressure chambers 33A and 34A as the first pressure chambers are communicated with the one feedback flow passage 21, and the pressure chamber 3 as the second pressure chamber 3 is connected.
Although 3B and 34B are configured to communicate with the other feedback flow channel 22, the pressure chambers 33A and 34A are communicated with one feedback flow channel 21 and the pressure chamber 33 is communicated.
B and 34B may be sealed, or the pressure chambers 33B and 34B may be connected to the other feedback flow path 2
Alternatively, the pressure chambers 33A and 34A may be connected to each other and the pressure chambers 33A and 34A may be hermetically sealed. Further, in the above embodiment, the two pressure fluctuation detecting units 33 and 34 are provided, but if it is not necessary to distinguish whether the vibration is based on fluid vibration or from external influences, Only one of them may be used. In this case, the circuit board 50 does not require any one of the alternating current detection circuits 52A and 52B and the comparison determination circuit 53.

[0042]

As described above, according to the fluid vibration detecting sensor and the fluidic flowmeter of the present invention, the vibration state of the vibrating membrane based on the fluctuation of the differential pressure is converted into the fluctuation of the magnetic field, and based on the fluctuation of the magnetic field. Since the electric signal is generated according to the fluid vibration, it is not necessary to use the piezoelectric film having the metal film formed on the surface as the vibrating film, and the vibrating film can be formed by the corrosion-resistant insulating material. .
Therefore, there is no risk of corrosion due to gas in the fluid, oil mist, etc., erroneous detection of fluid vibration can be prevented, and detection accuracy is significantly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a fluidic flow meter according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a flow meter main body in the fluidic flow meter shown in FIG.

FIG. 3 is a cross-sectional view showing a configuration of a fluid vibration detection sensor used in the fluidic flow meter shown in FIG.

4 is a partial cross-sectional perspective view showing the configuration of an electromagnetic induction coil in the fluid vibration detection sensor shown in FIG.

5 is a circuit configuration diagram showing a circuit configuration of the fluid vibration detection sensor shown in FIG.

FIG. 6 is a cross-sectional view for explaining the operation of the fluid vibration detection sensor shown in FIG.

[Explanation of symbols]

 10 Flowmeter main body 11 Inlet part 14 Nozzle part 21,22 Feedback flow path 30 Fluid vibration detection sensor 31A, 31B Pressure guide port 33, 34 Pressure fluctuation detection part 33A, 34A Pressure chamber (first pressure chamber) 33B, 34B Pressure Chamber (second pressure chamber) 35 Vibration film 40A, 40B Fluid vibration detection means 41 Electromagnetic induction coil 42 Magnet 50 Circuit board 52A, 52B AC current detection circuit 60 Flow rate calculation unit

Claims (5)

[Claims] 1. A pressure fluctuation detecting section having a first pressure chamber and a second pressure chamber, wherein a pressure fluctuation is introduced according to fluid vibration, and the pressure fluctuation detecting section is formed of a corrosion-resistant insulating material. A partition wall is formed between the first pressure chamber and the second pressure chamber in the fluctuation detection unit, and vibrates due to fluctuations in the differential pressure between the two pressure chambers based on the pressure fluctuations introduced into the pressure fluctuation detection unit. The vibrating membrane and the vibration state of this vibrating membrane are converted into the fluctuation of the magnetic field,
A fluid vibration detecting sensor, comprising: a fluid vibration detecting means for outputting an electric signal according to the fluid vibration by detecting the magnetic field fluctuation. 2. The fluid vibration detecting means includes an electromagnetic induction coil arranged at either a predetermined position in the pressure chamber or a predetermined position on the surface of the vibrating membrane, and a predetermined position in the pressure chamber. Or a magnet that is disposed at either one of the predetermined positions on the surface of the vibrating membrane and that relatively reciprocates in the electromagnetic induction coil according to the vibration state of the vibrating membrane. The fluid vibration detection sensor according to claim 1. 3. A pressure based on fluid vibration of one of two flow paths in which fluid flows alternately is introduced into the first pressure chamber, and a pressure based on fluid vibration of the other flow path is adjusted. The fluid vibration detection sensor according to claim 1, wherein the fluid vibration detection sensor is configured to be introduced into the second pressure chamber, and detects fluid vibration of a fluid that alternately flows through two flow paths. 4. A pair of pressure fluctuation detection units are provided, and the vibrating membranes of these pressure fluctuation detection units are arranged in parallel with each other, and the positional relationship of each of the first pressure chamber and the second pressure chamber with respect to the vibrating membrane. Are set to be opposite to each other, and the pressure based on the fluid vibration of one of the two flow paths in which the fluid flows alternately is set to the first pressure of each of the two pressure fluctuation detection units.
4. The pressure chamber according to claim 3, and the pressure based on the fluid vibration of the other flow path are introduced into the second pressure chamber of each of the two pressure fluctuation detection units. Fluid vibration detection sensor. 5. An inlet portion for receiving a fluid, a nozzle portion for allowing the fluid received from the inlet portion to generate a jet flow, and a pair of feedbacks for guiding the fluid passing through the nozzle portion to a jet outlet side of the nozzle portion. 5. A fluid flow is alternately introduced through the pair of feedback flow passages to detect fluid vibration.
And a flow rate calculating means for calculating the flow rate of the fluid received from the inlet portion based on the fluid vibration detected by the fluid vibration detecting sensor. Total.