JPS62102119A - Fluidic flow meter - Google Patents

Abstract

PURPOSE:To attain accurate flow rate measurement over a wide range by forming a straight barrel part connected to a small diameter side end part of a pressure adjusting part for increasing a valve opening in accordance with the increase of a flow rate to maintain a difference pressure between upper and downstream side within a set range to a slide valve body and arranging a valve body full opening magnet for holding the opening of the slide valve body on the inside of a pressure room. CONSTITUTION:The valve body full opening magnet 23 for holding the opening of the slide valve body 16 is arranged on the inside of a pressure room 18a so as to adsorb a magnetic substance 24 fitted to a rod 20 on a position where the straight barrel part 16b is drawn out from a valve seat 22 and a spacer 25 consisting of a non-magnetic substance is arranged between the magnet 23 and the magnetic substance 24. Consequently, the magnet 23 can be prevented from deterioration of its functions due to dust and a governor valve C can be prevented from operational defect due to excess adsorption of the magnet 23.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is characterized in that a conduit constriction section, a jet nozzle, and a conduit enlarged section are formed in sequence in the flow direction, and the jet nozzle and the conduit enlarged section are A pair of control nozzles are formed at the boundary of the jetting nozzle in a direction substantially perpendicular to the jetting direction of the jetting nozzle and facing each other; The measurement part forms a pair of return flow paths connecting the pipes, in other words, the jet flow from the jet nozzle connected to the conduit constriction part is stabilized along one slope of the conduit enlarged part, and the control By using the phenomenon that the jet flow from the jet nozzle flows alternately along both inclined surfaces of the expanded pipe section by jetting liquid alternately from the nozzle, fluid vibration is caused by the change in the flow direction of the jet from the jet nozzle. 2 of the measuring section configured to measure the flow rate based on a change in the number of
are connected in series, the ejection nozzle of the first measuring section is formed to have a smaller opening area than the ejection nozzle of the second measuring section, and a bypass flow path that bypasses the first measuring section is formed. A return type fluid connected to the second measuring section and provided with a diaphragm type governor valve in its bypass flow path in such a way that the differential pressure between the upstream pressure and the downstream pressure is maintained within a set range within the measured flow rate range. Regarding Dick flowmeters.

[Conventional technology]

The above-mentioned flowmeter was proposed in Japanese Patent Application No. 60-6634 as a device that can always measure the flow rate with high accuracy regardless of wide flow rate changes.
No. 5 and Japanese Patent Application No. 60-160820, it was previously proposed, and was configured as shown in FIG. 6, for example.

In other words, the sliding valve body (16a) of the governor valve (C) is formed into a conical shape so that the valve opening degree increases as the flow rate increases in order to maintain the set range of the differential pressure (PI-Pz). , so as to be always located within the valve seat (22), and the configuration was such that the change in differential pressure (p+-pg) accompanying the change in flow rate was as shown in FIG.

More specifically, when the flow rate gradually increases from zero,
At first, the differential pressure (P+-Pg) is small, so the valve body (16a
) is fully opened by the spring (21), and the fluid flows to the second
flows from the measuring section (B) to the first measuring section (A), and the differential pressure (
h-Pg) rises from point (A) to point (C) beyond point (0) corresponding to the first set differential pressure (APυ).Then, the differential pressure (p+-pg) rises to the second set pressure (C). When APz) is reached,
The valve body (16a) is opened so that the differential pressure (p+-p2) is maintained at the first set differential pressure (Ap+), and the differential pressure (Pt-h)
decreases from point (c) to point (d). and differential pressure (p+
-pg) is initially maintained constant by changing the opening degree of the governor valve (C) commensurate with the flow rate, and finally
) becomes fully open, it rises slightly and changes from point (D) to point (N) corresponding to the maximum flow rate.

[Problem that the invention seeks to solve]

However, when maintaining the pressure drop below 15 mmH2O, the range in which flow rate can be measured accurately is 10 to 3.0001! /h
However, in applications where flow rate changes are significant, the flow rate measurement range is still insufficient.

An object of the present invention is to further expand the range in which flow rate can be measured with high accuracy.

[Means for solving problems]

The characteristic configuration of the present invention is that a diaphragm type governor valve provided in a bypass flow path that bypasses a first measurement section with a small jet nozzle among the series-connected measurement sections, controls the differential pressure between the upstream pressure and the downstream pressure. In order to maintain the valve opening within the set range, the straight body part connected to the small diameter end of the pressure regulating part, which increases as the flow rate increases, is formed into a sliding valve body, and the straight body part slides out from the valve seat. The valve body fully opens magnet is provided to hold the sliding valve body open at the position where the valve body is opened, and its effects are as follows.

[For production]

That is, when the flow rate gradually increases from zero, the change in differential pressure (p, -p1) accompanying the change in flow rate becomes as shown in FIG. 4, and will be described in more detail as follows.

The pressure regulating part of the sliding valve body is located within the valve seat, and the differential pressure (p+-p
The changes up to the point (to) where g) is maintained within the set range (Ap+) are the same as in the conventional example explained earlier with reference to FIG.

When the point (to) is reached, the valve opening adjustment function by the pressure regulating part becomes null (and the differential pressure CP, -Pt) becomes even slightly large, and the sliding body valve body moves in the direction in which the straight body part comes out of the valve seat. moves, and if the movement is completed to a certain extent, the magnet for fully opening the valve body will act, and the straight body will come out of the valve seat and become fully open, and the differential pressure (PI-Pg) will change from point (to) to point. (G).

After that, the differential pressure (PI-Pg) gradually increases and changes from point (G) to point (H) corresponding to the maximum flow rate, and then to point (C).
The measurement range can be expanded compared to the conventional example by the difference between the flow rate at point (N) and the conventional maximum flow rate at point (N).

Furthermore, since the direct body portion is provided to prevent the adverse effect of the adsorption action of the magnet for fully opening the valve body from affecting the valve opening adjustment by the pressure regulating portion, good operation of the governor valve can be stably obtained.

〔Effect of the invention〕

As a result, we are now able to provide feedback-type fluidic flowmeters that are useful when large changes in flow rate occur frequently and accurate flow rate measurement is required, such as for customer meters in city gas pipelines and water supply. Ta.

By the way, in order to maintain the pressure drop below 15■H20, the above-mentioned conventional type can only cope with a flow rate change of about 10 to 3,0001/h, but when the measurement configuration of the present invention is used, It was able to cope with a flow rate change of about 1/h, and the performance required for a residential city gas meter was sufficiently achieved.

〔Example〕

Next, an example will be shown with reference to FIGS. 1 to 4.

A small channel (13) with a small opening area and a bypass channel (15) with a large opening area are defined by a partition wall (9) on the downstream side of the pipe (1). A first measuring section (A), which will be described later, is provided, a second measuring section (B), which will be described later, is provided upstream of the small channel (13) and the bypass channel (15), and a second measuring section (B), which will be described later, is provided on the upstream side of the small channel (13) and the bypass channel (15). A diaphragm governor valve (C) is provided to open and close it.

The measurement units (A) and (B) have similar configurations and are configured as follows.

A pair of first flow path forming members (4a) and (4b) forming the pipe constriction portion (2) and the jet nozzle (3) are arranged symmetrically with respect to the pipe central axis (P), and the pipe Road reduction part (2)
The fluid is smoothly guided to the jet nozzle (3) by the action of
The jet nozzle (3) is configured to jet fluid approximately parallel to the pipe center axis (P), and the pipe enlarged portion (5)
, a pair of control nozzles (6a), (6b), and the downstream side of the conduit enlarged portion (5) and the control nozzle (6a).

(6b), a pair of return channels (7a) that communicate with each other separately;
A pair of partition walls (8a) and (8b) forming (7b)
) are arranged symmetrically with respect to the tube center axis (P), and a pair of control nozzles (6a) and (6b) are connected to the jet nozzle (
3) and the expanded pipe section (5), the jet nozzle (3)
A pair of second flow path forming members (12a), (12a) which are oriented substantially perpendicularly to the ejection direction of
b) are arranged symmetrically with respect to the tube center axis (P).

In other words, when fluid ejection from the ejection nozzle (3) starts, the ejected fluid flows to one partition wall (8a) due to the Coanda effect.
), and therefore large fluid energy is applied from the return flow path (7a) to the control nozzle (6a) located on the partition wall (8a) side, and the ejected fluid flows along the partition wall (8b) on the opposite side. The fluid energy from the control nozzle (6b) on the opposite side causes the ejected fluid to flow again along the partition wall (8a) along which it started, and in this way the ejecting nozzle (3) ) so that the fluid flows along the partition walls (8a) and (8b) alternately, so that as the amount of fluid ejected increases, the period becomes shorter,
Further, the flow direction of the ejected fluid is configured to change in a state where there is a quantitative correlation.

A targera (14) is provided on the downstream side of the expanded pipe section (5) to further stabilize the change in flow direction of the ejected fluid.

The opening area of the jet nozzle (3) of the first measuring section (A) is smaller, for example, 1728, than the opening area of the jet nozzle (3) of the second measuring section (B). Therefore, the correlation between the flow rate and the frequency of change in the flow direction of ejected fluid has good accuracy in the first measurement part (A) in the small flow rate range, and good accuracy in the second measurement part (B) in the large flow rate range. It is configured as follows.

One return flow path (7a) of each of the measurement parts (A) and (B)
), there is a sensor (
10), and a flow rate display device (11) that calculates and displays the flow rate from the frequency of the pressure or flow rate change based on the information from both sensors (10).
It consists of a feedback type fluidic flow meter.

The governor valve (C) has a differential pressure (p, -p1) between an upstream pressure (Pl) and a downstream pressure (P2) in a set flow rate range.
In order to maintain it within the set range, it is configured as follows.

A diaphragm (17) interlocked with a sliding valve body (16) that opens and closes the bypass flow path (15) is connected to a pressure chamber (18a) that communicates with the upstream side of the valve body (16) through a passage (19), and a valve. A spring (21) is provided facing the pressure chamber (18b) that communicates with the downstream side of the body (16), and biases the rond (20) attached to the sliding valve body (16) in the valve closing direction. It is provided. In addition, in order to maintain the differential pressure (PI-Pz) within a set range, a pressure regulating part (16a) such as a conical shape whose valve opening degree increases as the flow rate increases, and a pressure regulating part (16a) of the pressure regulating part (16a). The straight body part (16b) connected to the small diameter end is connected to the sliding valve body (16
), and when the straight body part (16b) is inserted into the valve seat (22), the valve opening degree is configured to be approximately constant even if the sliding valve body (16) moves. It is. Also, the third
As shown in the figure, the magnet (23) for fully opening the valve body, which holds the sliding valve body (16) open at the position where the straight body (16b) has come out of the valve seat (22), is attached to the rond (20). The pressure chamber (
A spacer (25) made of a non-magnetic material is provided in
) is interposed between the magnet (23) and the magnetic body (24), and the governor valve (
The structure is such that the malfunction of C) can be prevented. In short, it operates as detailed above with reference to FIG.

The flow rate display device (11) includes a means (lla) for determining whether the frequency in the first information from the sensor (10) of the second measuring section (B) is equal to or lower than a setting, and a determining means ( lla), when the frequency of the first information is below the setting, the sensor (10) of the first measuring section (A)
means (Ilb) for calculating the flow rate based on the second information from the source and based on the first information when the vibration frequency of the first information exceeds a set value; and means (Ilb) for displaying the calculated flow rate. llc), for example 10 to 4.0001
This makes it possible to perform accurate measurements while keeping the differential pressure to 15 w Hz O or less over a wide range of 15 w Hz O or less.

In addition, the set frequency of the measuring means (lla) is set to the first
The minimum frequency in the information and the frequency corresponding to the opening of the valve body (16) are set to approximately the intermediate value, and the flow rate measurement using the first information is checked to ensure that there is no error due to linearity deterioration in the correlation between flow rate and frequency. It is configured so that it can be carried out in a state where the number of measurements is extremely small, and so that measurement errors due to the opening of the valve body (16) do not occur.

That is, the flow rate is calculated based on the first information before the valve body (16) opens, and conversely, when the valve body (16) opens, the frequency of the valve opening and the lowest frequency of the first information are calculated. When the vibration becomes lower than the intermediate vibration, the flow rate is calculated using the second information.

[Another example]

Next, another embodiment will be described.

The specific configuration of the governor valve (C) can be changed appropriately, for example,
As shown in FIG. 5, the magnetic body (24) is connected to the sliding valve body (16).
) and attach it to the end face of the magnet (23) or spacer (2).
5) in the bypass flow path (15), or place the spacer (
25) may be omitted.

When connecting two measuring parts (A) and (B) in series,
The first measurement section (A) with a small ejection nozzle (3) may be arranged upstream of the second measurement section (B) with a large ejection nozzle (3).

The detection method, configuration, number of sensors, etc. of the sensor (10) can be changed freely, for example, both return channels (7a) and (7b)
A sensor (10) may be provided at. Further, the device (11) for detecting and displaying the flow rate can also be changed in various ways.

Flowmeters are mainly used for domestic purposes, such as fuel gas and water supply, but their use is not specific.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention, in which FIG. 1 is an overall sectional view, FIG. 2 is a sectional view taken along the line nn of FIG. The figure is a graph showing changes in differential pressure with changes in flow rate. FIG. 5 is a sectional view of a main part showing another embodiment of the present invention. FIG. 6 is a sectional view of the conventional example, and FIG. 7 is a graph showing changes in differential pressure with changes in flow rate in the conventional example. (2)...Pipe constriction section, (3)...Ejection nozzle, (5)...Pipe enlargement section, (6a)
, (6b)...control nozzle, (7a),
(7b)...Return flow path, (15)/\Inomas flow path, (16)...Sliding valve body, (16a)...
...Pressure regulating part, (16b) ... Straight body part, (2
2) Valve seat, (23) Magnet, (A) First measuring section, (B)
...Second measuring section, (C)...Governor valve.

Claims (1)

[Claims] Pipe constriction section (2), jet nozzle (3) and conduit enlargement section (
5) are formed in series in the flow direction, and a pair of control nozzles (6a) and (6b) are provided at the boundary between the jet nozzle (3) and the expanded pipe section (5). ) are formed in a direction substantially perpendicular to the ejection direction of the control nozzles (6a) and (6b), and are formed opposite to each other, and connect the downstream side of the conduit enlarged portion (5) with each of the control nozzles (6a) and (6b). Measuring sections (A) and (B) forming a pair of return channels (7a) and (7b)
) are connected in series, and the ejection nozzle (3) of the first measurement section (A) has a smaller opening area than the ejection nozzle (3) of the second measurement section (B). A bypass flow path (15) which is formed and bypasses the first measurement section (A) is connected to the second measurement section (B), and the bypass flow path (15) is connected to the second measurement section (B).
15), a diaphragm type governor valve (C) is installed to control the upstream pressure (P_1) and downstream pressure (P_2) in the measured flow rate range.
) is a feedback fluidic flowmeter installed in such a way that a differential pressure (P_1-P_2) between A pressure regulating part (16a) that increases the valve opening degree as the flow rate increases in order to maintain the pressure (P_1-P_2) within a set range, and a straight body connected to the small diameter side end of the pressure regulating part (16a). Part (16
b), and is provided with a magnet (23) for fully opening the valve body, which holds the sliding valve body (16) open at the position where the straight body portion (16b) has come out of the valve seat (22). type fluidic flowmeter.