JPH04136524U - fluidics flow meter - Google Patents

Abstract

(57) [Summary] (with modifications) [Purpose] To obtain a fluidic flowmeter that uses a directional condenser microphone as a fluid vibration detection sensor in which pipe noise does not cause measurement errors. [Configuration] An input sensitivity control body 10 is inserted into the front side of the directional condenser microphone 9, and the microphone 9
The fluid vibration level input to the front side is suppressed to be lower than that on the rear side, thereby reducing the difference between the sensing level on the front side and the sensing level on the rear side due to the high sensitivity on the front side, which is a characteristic of the microphone 9. Make it as small as possible. [Effects] By using the directional condenser microphone 9 as a sensor, the cost becomes low, and since almost no signal is generated due to the pipe noise that is input in the same phase, the pipe noise does not become a cause of measurement error.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention introduces the fluid to be measured from the nozzle of the fluidic element into the fluid vibration generation chamber. The fluid is ejected to generate fluid vibration, and this fluid vibration is detected by a fluid vibration detection sensor. This relates to a fluidic flow meter that calculates flow rate by

0002

[Conventional technology]

In a fluidic flowmeter, a piezoelectric film is used as a fluid vibration detection sensor. (Utility Model 62-128325) and a condenser microphone. (Utility Model Application Publication No. 57-92121) is publicly known.

0003

[Problem that the idea aims to solve]

However, the former method, which uses a piezoelectric film, requires a lot of work and is difficult to manufacture when commercialized. The disadvantage is that it is expensive, and the latter type of microphone has the disadvantage of being expensive. Due to the characteristics of the Lophone, there is a drawback that noise within the pipe becomes a cause of measurement error.

0004 The purpose of this invention is to use a directional condenser microcontroller that is inexpensive and unaffected by tube noise. By providing a fluidic flowmeter that uses a cell phone as a fluid vibration detection sensor, be.

[0005]

[Means to solve the problem]

The configuration of the fluidic flowmeter according to the present invention is as follows.

[0006] 1. A directional condenser is used as a sensor to detect fluid vibrations generated in a fluidic element. When using a sensor microphone, the front side and An input sensitivity control body is installed to minimize the output generated due to the difference in sensitivity on the rear side. A fluidic flowmeter that is attached to a

[0007] 2. A directional condenser microphone is inserted in the middle of the sound insulating casing, and this The front and back sides of the directional condenser microphone in the sound isolation casing. In addition to connecting the impulse pipe extended from the fluidic vibration detection port of the fluidic element, The input sensitivity control body is inside the sound insulating casing and is connected to the directional condenser microphone. A fluidic flowmeter inserted into the front side.

[0008]

[Effect]

The fluid to be measured ejected from the nozzle of the fluidic element is placed inside the fluid vibration generation chamber. This fluid vibration signal is transmitted by a directional condenser microphone. The signals are input to both the front and rear surfaces with opposite phases. At this time, the signal input to the front side is The front side sensitivity, which is a characteristic of directional condenser microphones, is controlled by the force sensitivity controller. The signal level input to the front side is actually lower than that to the rear side. becomes smaller. However, the sensitivity of a directional condenser microphone is lower on the front side. Since the level detected by the front side of the directional condenser microphone is higher than that of the front side, The level is almost the same as the level sensed by the rear side. The front side and the rear side receive signals with opposite phases. As a result, the microphone is at the front sensing level ( Alternatively, a signal with a level twice that of the sensing level on the rear surface side is output. For this reason, the fluid Vibration signals can be detected. On the other hand, in the same phase, the directional condenser microphone In the case of pipe noise input to the front side, if there is no input sensitivity control unit, Even if the signal level input to the rear panel and the signal level of the noise input to the rear panel are the same, there will be a difference in sensitivity. This results in outputting a signal similar to the vibration frequency of the fluid, but the input The signal level on the front side is kept low by the sensitivity control unit due to its high sensitivity. , the level sensed by the front side of the directional condenser microphone and the level sensed by the rear side. The levels of the input signals are almost the same, and as a result, the signals input in the same phase is canceled and the microphone outputs almost no signal. As a result, the tube Internal noise is not a cause of measurement error.

[0009]

【Example】

In FIG. 1, 1 is a fluidic element, 2 is a nozzle, 3 is a fluid vibration generation chamber, 4 and 4a are fluid vibration detection ports, and 5 is a directional condenser microphone 9 installed in the middle. The front 6 side of the directional condenser microphone 9 is is connected to the fluid vibration detection port 4 through a pressure guiding pipe 8.

0010 7 is located on the rear side of the directional condenser microphone 9, and is connected to the fluid vibration detection port 4a. They are connected via a pressure impulse pipe 8a.

[0011] 10 is an input with a signal level control port 11 having a diameter of 3 mm in the center as shown in Fig. 2. As a force sensitive control body, this input sensitivity control body 10 is a directional condenser microphone. It is installed in the casing 5 at the front of the engine 9. 12 is amplification/waveform shaping 13 is an arithmetic unit, and 14 is a display section.

0012 Note that in the above embodiment, the directional condenser microphone 9 is placed inside the sound insulating casing 5. The impulse pipes 8 and 8a are connected to the sound insulating casing 5, respectively. The diaphragm of the microphone is directly incorporated into the sound casing 5, and the sound insulating casing 5 It may also be used as a directional condenser microphone.

[0013] Next, in the embodiment, a fluid vibration input control port 11 is provided in the center as the input sensitivity control body 10. Although a girder plate is used, the shape of the input control port 11 is not particularly limited. The plate is a so-called punching metal or net with many input control ports. Good too. In addition, as an alternative to the input sensitivity control body, the throttle can be installed inside the impulse pipe or at its inlet. Alternatively, the same effect can be expected by forming it at the outlet.

[0014] In the case of the embodiment, fluid flows from the nozzle 2 of the fluidic element 1 to the fluid vibration generating chamber 3. When the fluid is ejected inside, fluid vibration is generated in this fluid vibration generating chamber 3, and this fluid vibration The vibration is transmitted into the sound insulating casing 5 via the fluid vibration detection ports 4, 4a and the impulse pipes 8, 8a. input, the input level is kept low by the input sensitivity control body 10 on the front 6 side, and The surface 7 side is input as is. This input is out of phase, so a directional capacitor The microphone 9 measures the vibration frequency and outputs it as an electrical signal to the computing unit 13. Ru. On the other hand, the pipe noise is input into the sound insulating casing 5 in the same phase, but the input sensitivity is Keeps the level of the sensitive front side of the directional condenser microphone low on your body Therefore, the directional condenser microphone 9 outputs almost no signal. Therefore, pipe noise does not become a cause of measurement error.

[0015] Figure 3 shows the sensitivity difference when the present invention is implemented, and Figure 4 shows the case where the control board 10 is not installed. shows the difference in sensitivity.

In FIG. 5, the P line shows an example of the effect of pipe noise based on the results of implementing the present invention, and the ^P0 line shows an example of the effect of pipe noise when using a conventionally known non-directional condenser microphone. There is.

[0017]

[Effect of the idea]

As described above, the present invention uses a directional condenser microphone as a fluid vibration detection sensor. By using it as a service, an inexpensive fluidic flowmeter can be provided.

[0018] Next, as a characteristic of a directional condenser microphone, the higher sensitivity on the front side is , because the input sensitivity control body suppresses the input signal level to a lower level than the rear side. The signal level sensed by the microphone is the same both before and after, and as a result, , the tube noise input to the microphone in the same phase is canceled. This makes it possible to measure the flow rate more accurately.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a fluidic flowmeter implementing the present invention.

FIG. 2 is a front view of the input sensitivity control body (plate).

FIG. 3 is an explanatory diagram of sensitivity differences in an example in which an input sensitivity control body is attached.

FIG. 4 is an explanatory diagram of the sensitivity difference when no input sensitivity control body is attached.

FIG. 5 is an explanatory diagram of tube noise when a directional condenser microphone with an input sensitivity control body attached to the front side is used and when a conventionally known non-directional condenser microphone is used.

[Explanation of symbols]

1 Fluidic element 2 nozzles 3 Fluid vibration generation chamber 4, 4a Fluid vibration detection port 5 Sound insulation casing 6 Front 7 Rear side 8, 8a Impulse tube 9 Directional condenser microphone 10 Input sensitivity control body 11 Small hole 12 Amplification/waveform shaping circuit 13 Arithmetic unit 14 Display section

Claims (5)

[Scope of utility model registration request] [Claim 1] A directional condenser microphone is used as a sensor for detecting fluid vibrations generated in a fluidic element, and the output generated by the difference in sensitivity between the front side and the rear side is placed on the front side of this microphone as much as possible. A fluidic flowmeter equipped with a small input sensitivity control body. [Claim 2] A directional condenser microphone is inserted in the middle of a sound insulating casing, and impulse tubes extending from the fluid vibration detection port of the fluidic element are connected to the front and rear sides of the directional condenser microphone, respectively, in the sound insulating casing. At the same time, this fluidic flowmeter has an input sensitivity control body inserted inside a sound insulating casing and on the front side of a directional condenser microphone. 3. The fluidic flowmeter according to claim 1, wherein the input sensitivity control body comprises a plate having a small hole in the center. 4. The fluidic flowmeter according to claim 1, wherein the input sensitivity control body is made of punched metal with a large number of small holes. 5. The fluidic flowmeter of claim 1, wherein the input sensitivity control body comprises a net.