JP3334736B2 - Flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter having a mechanism for absorbing pressure fluctuation of a fluid.

[0002]

2. Description of the Related Art Fluid flow meters are known as flow meters used in gas meters and the like. This fluidic flow meter forms an enlarged flow path portion with a pair of side walls on the downstream side of a nozzle that generates a jet flow,
A return guide provided on the outside of the side wall forms a pair of feedback passages for guiding the fluid passing through the nozzle to the nozzle outlet side along the outside of each side wall. The flow rate of the fluid is measured based on the frequency and the period of the fluidic oscillation by using a phenomenon (in the present application, referred to as fluidic oscillation) that flows alternately in a path.

[0003] In this fluidic flow meter, if fluidic oscillation is disturbed due to fluctuations in the pressure of the fluid on the upstream side, accurate measurement of the flow rate may not be possible. Therefore, conventionally, for example, in FIG.
The pressure fluctuation absorbing mechanism shown in FIG. The pressure fluctuation absorbing mechanism is provided on the partition 110 provided in the fluidic flow meter, a small-diameter opening 111 for absorbing pressure fluctuation provided on the partition 110, and provided on the partition 110.
Large-diameter opening 11 having a larger opening area than opening 111
2 and a float valve 1 for opening and closing the opening 111 for a small flow rate
20 and a large flow rate float valve 130 for opening and closing the opening 112. The float valve 120 has a float valve body 121, a shaft 122 connected to the float valve body 121, and a guide 122 that slidably supports the shaft 122. Similarly, the float valve 130 includes a float valve body 131 and the float valve body 1.
A shaft 132 connected to the shaft 31;
And a guide 132 that slidably supports the guide 2.
The float valve 131 is heavier than the float valve 121.

In this pressure fluctuation absorbing mechanism, when the flow rate of a fluid, for example, gas is small, the float valve body 121 of the float valve 120 for small flow rate is lifted by the gas pressure, and the gas flows as indicated by an arrow 140 in the figure. Pass through the small-diameter opening 111. At this time, the opening 111 and the gap between the partition wall 110 and the float valve body 121 act as a resistance to absorb the pressure fluctuation of the gas. When the flow rate of the gas is large, the float valve element 131 of the float valve 130 for a large flow rate is also lifted by the pressure of the gas,
The gas also passes through the large-diameter opening 112, and the pressure loss is kept low.

[0005]

However, in such a pressure fluctuation absorbing mechanism, when the flow rate is constant, the two float valves 120 and 130 cannot be well balanced.
There is a problem that both or one of the valves tends to cause pressure hunting that vibrates in the vertical direction. Further, when the shutoff property of the float valve 130 for a large flow rate is reduced due to adhesion of dust and mist, there is a problem that the pressure fluctuation absorbing effect is significantly reduced.

The present invention has been made in view of the above problems, and has as its object to prevent a valve for absorbing pressure fluctuation from performing unstable operation and to prevent dust and mist from adhering to the valve. An object of the present invention is to provide a flow meter capable of securing a pressure fluctuation absorbing effect.

[0007]

According to a first aspect of the present invention, there is provided a flowmeter for forming a flow path from a fluid inlet to an outlet, and a flowmeter for measuring a flow rate of a fluid passing through the flow path. A measuring means, a partition separating the upstream side and the downstream side in the flow path, a first opening for absorbing pressure fluctuation provided in the partition, and an opening area provided in the partition and larger than the first opening A large opening, a first valve that opens and closes the first opening by the pressure of the fluid, a second valve that is electrically driven to open and close the second opening, and flow rate measuring means And a valve control means for controlling the second valve in accordance with the flow rate measured by the control means.

In this flow meter, the first pressure is determined by the pressure of the fluid.
Valve opens and closes the first opening, and the fluid passes through the first opening to absorb the pressure fluctuation of the fluid. The second valve is controlled by valve control means according to the flow rate, and is electrically driven to open and close the second opening.

According to a second aspect of the present invention, in the flow meter according to the first aspect, the valve control means closes the second opening when the flow rate measured by the flow rate measuring means is equal to or less than a predetermined flow rate. When the flow rate exceeds a predetermined flow rate, the second valve is controlled so as to open the second opening so as to suppress the pressure loss at the time of a large flow rate.

According to a third aspect of the present invention, there is provided a flow meter according to the first or second aspect, wherein the flow rate measuring means is provided on a downstream side of the partition wall and generates fluidic oscillation by a fluid ejected from a nozzle. A Dick oscillation generator,
A fluidic oscillation detection sensor that detects fluidic oscillation generated by the fluidic oscillation generation unit; and a flow rate calculating unit that calculates a flow rate based on the output of the fluidic oscillation detection sensor. It is configured to measure the flow rate by utilizing.

[0011]

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

FIG. 1 is a sectional view showing the structure of a flow meter according to one embodiment of the present invention. The flow meter according to the present embodiment is used as a gas meter. As shown in FIG. 1, the flow meter includes a main body 10 having an inlet 11 for receiving gas (gas) and an outlet 12 for discharging gas. In the main body 10, a partition wall 1 separating the upstream side and the downstream side is provided.
3 is provided, a gas flow path 14 is formed between the partition 13 and the inlet 11, and a gas flow path 15 is formed between the partition 13 and the outlet 12. The partition 13 is formed with a small-diameter opening 41 for absorbing pressure fluctuations and a large-diameter opening 42 having an opening area larger than the opening 41.
Above the opening 41, the opening 41
A float valve 43 is provided as a first valve for opening and closing the valve. The float valve 43 has a float valve body 44 that can close the opening 41, a shaft 45 connected to the float valve body 44, and a guide 46 that slidably supports the shaft 45. . On the other hand, above the opening 42, an electromagnetic valve 47 as a second valve for opening and closing the opening 42 is provided. The solenoid valve 47 is provided with the opening 4
A valve body 48 capable of closing the valve body 2, a shaft 49 connected at one end to the valve body 48, the other end of which penetrates a side wall of the main body 10 and is led out, and a shaft 49 provided outside the main body 10. Actuator 5 consisting of a solenoid that moves forward and backward
0.

A nozzle 21 is provided in the gas flow path 15 to generate a jet by passing the gas received from the inlet 11. Downstream of the nozzle 21, a pair of side walls 23 and 24 forming an enlarged flow path are provided. A predetermined interval is provided between the side walls 23 and 24 so that the target 25 is located upstream and the target 26 is located downstream.
Are arranged respectively. A return guide 29 is formed outside the side walls 23 and 24 to form a pair of feedback flow paths 27 and 28 for returning the gas that has passed through the nozzle 21 to the jet port side of the nozzle 21 along the outer periphery of each side wall 23 and 24. Are arranged. Feedback channel 27, 2
8 between the outlet portion and the outlet portion 12, a pair of discharge paths 3 is provided by the back surface of the return guide 29 and the main body 10.
1, 32 are formed. Portions extending from the nozzles 21 to the discharge paths 31 and 32 correspond to a fluidic oscillation generation unit in the present invention.

In the vicinity of the nozzle 21 of the nozzle 21, a pressure guiding hole 3 is provided.
3 and 34 are provided on the outer side of the bottom of the main body 10 through a pressure guiding passage (not shown) to the pressure guiding holes 33 and 34 to detect a pressure difference between the pressure guiding hole 33 and the pressure guiding hole 34. A piezoelectric film sensor 35 (not shown in FIG. 1) as a Dick oscillation detection sensor is provided.

FIG. 2 is a block diagram showing a configuration of a circuit portion of the flow meter shown in FIG. As shown in the figure, the flow meter includes an analog amplifier 51 for amplifying an output signal of the piezoelectric film sensor 35, a waveform shaping circuit 52 for shaping the output of the analog amplifier 51 to generate a pulse, and a waveform shaping circuit 52. A flow rate calculating section 53 for calculating the flow rate and the integrated flow rate based on the cycle of the output pulse of the circuit 52, and a display section 54 for displaying the integrated flow rate calculated by the flow rate calculating section 53
And a valve control unit 55 that controls the actuator 50 of the solenoid valve 47 according to the flow rate calculated by the flow rate calculation unit 53
And The valve controller 55 closes the opening 42 by the valve element 48 when the flow rate calculated by the flow rate calculation section 53 is equal to or less than the predetermined flow rate, and opens the opening 42 by the valve element 48 when the flow rate exceeds the predetermined flow rate. The actuator 50 is controlled at the same time.

The flow rate calculating section 53 and the valve control section 55
Is constituted by, for example, a microcomputer.

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

The gas received from the inlet 11 of the flow meter enters the nozzle 21 through the gas flow path 14 and the gas flow path 15 in this order. The gas that has passed through the nozzle 21 is jetted out of the jet port as a jet. The gas ejected from the ejection port flows along one side wall due to the Coanda effect. Here, it is assumed that the flow first flows along the side wall 23. The gas flowing along the side wall 23 is further fed into the feedback channel 2.
7, and is returned to the ejection port side of the nozzle 21, and the discharge path 3
1 through the outlet 12. At this time, the direction of the gas ejected from the nozzle 21 is changed by the gas flowing through the feedback channel 27, and the gas then flows along the other side wall 24. This gas is further returned to the ejection port side of the nozzle 21 through the feedback flow path 28 and discharged from the outlet section 12 through the discharge path 32. Then, the direction of the gas ejected from the nozzle 21 is changed by the gas flowing through the feedback channel 28, and the side wall 23 and the feedback channel 2 are returned again.
It flows along 7. By repeating the above operation, the gas that has passed through the nozzle 21 performs fluidic oscillation that alternately flows through the pair of feedback channels 27 and 28. The frequency and cycle of the fluidic oscillation have a correspondence with the flow rate. Fluidic oscillation is detected by the piezoelectric film sensor 35.

The flow rate calculating section 53 calculates the flow rate and the integrated flow rate based on the cycle of the pulse output from the waveform shaping circuit 52, and the display section 54 displays the integrated flow rate calculated by the flow rate calculating section 53.

Here, when the flow rate calculated by the flow rate calculation section 53 is equal to or less than a predetermined flow rate, the actuator 50 of the solenoid valve 47 is controlled by the valve control section 55 and the valve body 4 is controlled.
8, the opening 42 is closed. In this state, the float valve body 44 of the float valve 43 is lifted by the pressure of the gas, and the gas flows from the gas flow path 14 to the gas flow path 15 through the small-diameter opening 41. At this time, the opening 4
1, and the gap between the partition 13 and the float valve body 44 acts as a resistance to absorb the pressure fluctuation of the gas. On the other hand, when the flow rate calculated by the flow rate calculation section 53 exceeds the predetermined flow rate, the valve control section 55 controls the actuator 50 of the solenoid valve 47, and the valve body 48 opens the opening 42. As a result, the gas also passes through the large-diameter opening 42, and the pressure loss is kept low.

As described above, according to this embodiment,
Since the valve that opens and closes the opening 42 is the electromagnetic valve 47, pressure hunting due to the balance between the two valves, unlike the case where two float valves are used, does not occur. Even if dust or mist adheres to the valve body 48 of the solenoid valve 47, the valve body 4
8, the shutoff property of the opening 42 is ensured, so that the effect of absorbing the pressure fluctuation by the opening 41 and the float valve 43 is always ensured.

The present invention is not limited to the above embodiment,
For example, as a valve for opening and closing the opening 42, a solenoid valve 47
However, the present invention is not limited thereto, and an electric valve that moves the shaft 49 forward and backward by converting the rotation of the motor into forward and backward movement using a screw or the like may be used.

Further, the present invention can be applied to a flow meter for measuring the flow rate of not only gas but also liquid.

[0024]

As described above, according to the flowmeter of the present invention, the valve for electrically opening and closing the second opening having a larger opening area than the first opening for absorbing pressure fluctuation is electrically driven. Since the second valve is used, the valve for absorbing pressure fluctuation does not operate in an unstable manner, and the effect of absorbing pressure fluctuation can be ensured even if dust or mist adheres to the valve. This has the effect.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a circuit configuration of a flow meter according to one embodiment of the present invention.

FIG. 3 is a sectional view showing a pressure fluctuation absorbing mechanism in a conventional flow meter.

[Explanation of symbols]

 35 Piezoelectric film sensor 41 Opening (first opening) 42 Opening (second opening) 43 Float valve 47 Solenoid valve 48 Valve element 49 Shaft 50 Actuator 53 Flow rate calculation unit 55 Valve control unit

──────────────────────────────────────────────────続 き Continued on the front page (73) Patent holder 000142425 Kinmon Seisakusho Co., Ltd. 13-1, Oharacho, Itabashi-ku, Tokyo (73) Patent holder 000150109 Takenaka Seisakusho Co., Ltd. 1-1-1, Nakagawanishi, Ikuno-ku, Osaka-shi, Osaka No. 51 (73) Patent holder 000156813 Kansai Gas Meter Co., Ltd. 10 Nakadoji Kadamachi, Shimogyo-ku, Kyoto-shi, Kyoto (73) Patent holder 000222211 Toyo Gas Meter Co., Ltd. 2795 Motoe, Shinminato-shi, Toyama (72) Inventor Atsui Ikko 9-10 Misonodai, Fujisawa City, Kanagawa Prefecture (72) Inventor Hideo Kato 3-28-70-108 Minamisenju, Arakawa-ku, Tokyo (72) Inventor Katsuto Sakai 3-2-7 Takasago, Katsushika-ku, Tokyo −123 (72) Inventor Shigenori Okamura 4-1-2 Hiranocho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka Gas Co., Ltd. (72) Inventor Takato Sato 507-2, Shinhocho, Tokai City, Aichi Prefecture Kokusa Gas Co., Ltd. (72) Inventor Kanji Hirai 1-2-70 Chitose, Atsuta-ku, Nagoya City, Aichi Prefecture Aichi Watch Electric Machinery Co., Ltd. (72) Naoshi Isshiki 1-2, Shimura, Itabashi-ku, Tokyo 3 Central Research Institute, Kinmon Seisakusho Co., Ltd. (72) Inventor Masanari Imazaki 4-7-31 Nishiiwata, Higashi-Osaka-shi, Osaka Pref. 11 (72) Inventor Tadao Shibuya 2-10-16 Higashi-Kobashi, Higashinarashi-ku, Osaka-shi, Osaka Inside Kansai Gas Meter Co., Ltd. Shoji (56) References JP-A-4-145327 (JP, A) JP-A-4-109273 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 1/00-9 / 02

Claims (3)

(57) [Claims] 1. A flowmeter main body forming a flow path from an inlet to an outlet of a fluid, a flow measuring means for measuring a flow rate of a fluid passing through the flow path, and an upstream side in the flow path. A partition separating the downstream side, a first opening for absorbing pressure fluctuation provided in the partition, a second opening provided in the partition and having an opening area larger than the first opening, A first valve that opens and closes the first opening by the pressure of the fluid, a second valve that is electrically driven to open and close the second opening, and a flow rate measured by the flow rate measuring unit. And a valve control means for controlling the second valve accordingly. 2. The valve control means closes a second opening when the flow rate measured by the flow rate measuring means is equal to or less than a predetermined flow rate, and opens a second opening when the flow rate exceeds the predetermined flow rate. The flowmeter according to claim 1, wherein the second valve is controlled as described above. 3. The fluid flow measurement means is provided downstream of the partition wall, and generates a fluidic oscillation by a fluid ejected from a nozzle, and is generated by the fluidic oscillation generation unit. 3. The flowmeter according to claim 1, further comprising a fluidic oscillation detection sensor for detecting fluidic oscillation, and a flow rate calculating means for calculating a flow rate based on an output of the fluidic oscillation detection sensor.