JPS62175619A - Fluidic flowmeter - Google Patents

Abstract

PURPOSE:To detect a small flow rate of leakage on the downstream side, by opening a low different type opening/closing valve at an inlet or outlet of a measuring section smaller in the injection nozzle among measuring sections only when the pressure on the downstream side is lower than a set value on the upstream side. CONSTITUTION:A Reduced part 2 of a pipe line, an injection nozzle 3 and an expanded part 5 of the pipe line are arranged in order to form a meter. A pair of control nozzles 6a and 6b are formed on the bundle of the nozzle 3 and the expand section 5 roughly at a right angle to the injecting direction of the nozzle 3 while facing each other. Then, two measuring sections (A) and (B) are connected in series with a pair of feed back passages 7a and 7b formed to connect each of the nozzles 6a and 6b to the downstream side of the expanded part 5. A nozzle 3 at a measuring section (A) is formed with the smaller opening area than a measuring section (B). In addition, a bypass 15 detouring the measuring section (A) is connected to the measuring section. (B) and a diaphragm type governer valve (C) is provided in the bypass 15. In such a manner that the differential pressure between the pressure (P) on the upstream side and the pressure (P) on the downstream side will be maintained in a set range confined to a fixed flow rate range. The opening/closing valve (D) of the measuring section (A) is opened when the differential pressure is below a set value.

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 connected in this order. a pair of control nozzles at the boundary in a direction substantially perpendicular to the jetting direction of the jetting nozzle, and
A measurement section is formed facing each other and has a pair of return flow paths connecting each of the control nozzles and the downstream side of the conduit expansion section, in other words, the jet from the jet nozzle connected to the conduit constriction section is connected to the conduit condensation section. Utilizing the phenomenon that the channel is stabilized along one slope of the expanded channel, and by alternately blowing out fluid from the control nozzle, the jet stream from the jet nozzle flows alternately along the double-ended slope of the expanded channel. Utilizing this phenomenon, two of the measuring sections configured to measure the flow rate based on the change in fluid frequency caused by the change in the flow direction of the jet from the jet nozzle are connected in series. The ejection nozzle of the first one is formed to have a smaller opening area than the ejection nozzle of the second one, and a bypass passage that bypasses the first measurement part is connected to the second measurement part, and the bypass flow path is connected to the second measurement part. The present invention relates to a full-ink flowmeter in which a two-diaphragm governor valve is provided in a flow rate line so that the differential pressure between upstream pressure and downstream pressure is maintained within a set flow rate range.

[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. 7, for example.

In other words, when the flow rate gradually increases from zero, the differential pressure (p, -p2) is initially small, so the valve body (16) is fully closed by the spring (21), and the fluid flows to the second measuring section. (B
) from the first measuring section (A) to the first measuring section (A).
A change in the flow direction of the fluid ejected from the ejection nozzle (3) is detected by a pressure or flow rate change detection sensor (10) in the return flow path (7a), and based on the information from the sensor (10), a meteor is detected by the device. It is configured to be calculated and displayed in (11).

When the differential pressure (p, -p,) becomes equal to or higher than the set pressure, the valve body (16) is opened and the flow direction of the fluid ejected from the ejection nozzle (3) changes in the second measuring section (B). The pressure or flow rate detection sensor (10) in the return flow path (7a) detects the flow rate, and the flow rate is calculated and displayed by the device (11) based on the information from the sensor (10).

[Problem that the invention seeks to solve]

However, the range that can accurately measure the flow rate based on the information from the sensor (10) is about 10 to 30001/h, and when fluid transport is stopped, the flow rate on the downstream side of the flowmeter is 101/h.
Even if a leak occurs at a flow rate below this level, it is impossible to detect the leak based on the information from the flow rate measurement sensor (1o).

An object of the present invention is to enable detection of a small flow rate leak on the downstream side based on information from a flow rate measurement sensor.

[Means for solving problems]

The characteristic configuration of the present invention is that a low differential pressure operating type on-off valve is set at the inlet or outlet of the first measuring section having a small jet nozzle among the measuring sections connected in series, and the downstream pressure is set higher than the upstream pressure. The reason for this is that the valve is formed so as to open only when the temperature drops below a certain value, and its effects are as follows.

[For production]

In other words, if a small flow rate leak occurs on the downstream side when fluid transport is stopped, the pressure on the upstream side of the closed on-off valve is constant, but the downstream pressure gradually decreases, and the decrease in downstream pressure is the set point. When the value is reached, the on-off valve is opened briefly and the first
Although instantaneous, pressure fluctuations occur in the measurement section that are large enough to be detected by the flow measurement sensor, and the sensor sends a pulse signal that is completely different from that used during normal flow measurement.

Thus, by automatic means or by manual measurement of the signals from the sensors, leaks can be reliably detected regardless of their flow rate.

During fluid transport, the pressure on the downstream side of the on-off valve becomes sufficiently lower than the pressure on the upstream side of the on-off valve, and the on-off valve remains open, allowing the first and second measuring sections to accurately measure a wide range of flow rates.

〔Effect of the invention〕

As a result, it has become possible to prevent troubles due to leakage with equipment that is sufficiently simple and inexpensive compared to separately providing a special leakage detection means that makes effective use of a full-ink flow meter.

[For production]

Next, an embodiment will be shown with reference to FIGS. 1 to 6.

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 1 (A), which will be described later, is provided, and a second measuring section (B), which will be described later, is provided upstream of the small channel (13) and the bypass channel (15). A diaphragm type 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 was initially deflected, 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,
In addition, the ejection flow direction 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 ejection nozzle (3) of the first measurement part (A) is smaller, for example, 1728, than the opening area of the ejection nozzle (3) of the second measurement part (B). The correlation between the flow rate and the frequency of change in flow direction of the ejected fluid is such that the first measurement part (A) has good accuracy in the small flow rate range, and the second measurement part (B) has good accuracy 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 fluid flow meter.

The governor valve (C) is configured as follows to maintain the differential pressure (PI-P2) between the upstream pressure (P1) and the downstream pressure (P2) within the set flow rate range.

A diaphragm (17) linked to a valve body (16) that opens and closes the bypass flow path (15) is connected to a pressure chamber (18a) communicating with the upstream side of the valve body (16) through a passage (19), and a valve body ( 1
The pressure chamber (18b) communicating with the downstream side of the valve body (16) is provided with a spring (21) that biases the valve body (16) in the valve closing direction. In addition, the differential pressure (PI-
A pressure regulating part (16a) such as a conical shape that increases the valve opening degree as the flow rate increases in order to maintain the valve opening within the set range of P2), and
The straight body part (1
6b) is formed on the valve body (16), and when the straight body portion (16b) is inserted into the valve seat (22), the valve body (16)
The structure is such that the valve opening remains almost constant even if the valve moves. In addition, as shown in Fig. 3, a magneto l-(23) for fully opening the valve body is installed to hold the valve body (16) open at the position where the straight body part (16b) is pulled out from the valve seat (22). Valve body (16)
A spacer (25) made of a non-magnetic material is interposed between the magnet (23) and the magnetic material (24) to prevent dust from entering the magnetic material (23). ) functional deterioration and magnetism, 71- (
The structure is such that it is possible to prevent malfunction of the valve C) due to excessive suction force caused by 23).

That is, when the flow rate gradually increases from zero, the change in differential pressure (p+-pz) accompanying the change in flow rate becomes as shown in FIG. 6, and will be described in more detail as follows.

At first, the differential pressure (p+-pz) is small, so the valve body (16)
is fully closed by the spring (21), the fluid flows from the second measurement part (B) to the first measurement part (A), and the differential pressure (P
+-pz) increases from point (a) to point (c) beyond point (b) corresponding to the first set differential pressure (ΔP1). and,
When the differential pressure (hh) reaches the second set differential pressure (ΔPz),
The valve body (16) is opened so that the differential pressure (P, -P2) is maintained at the first set differential pressure (Δp+), and the differential pressure (P+-Pz)
decreases from point (c) to point (d). Then, the differential pressure (P
I-Pg) is initially maintained constant by changing the opening degree of the governor valve (C) according to the flow rate by the pressure regulating section (16a).

Then, when the point (to) is reached, the valve opening adjustment function by the pressure regulating part (16a) is lost, and if the differential pressure (P+-h) becomes even slightly large, the straight body part (16b) moves to the valve seat (22). ) The valve body (16) moves in the direction of exit from the valve seat (22), and when the valve body (16) moves to a certain extent, the magnet (23) for fully opening the valve body acts, and the straight body part (16b) is pulled out from the valve seat (22). is fully open, and the differential pressure (Pl-Pz) changes from point (to) to point (t).
decreases to After that, the differential pressure (PI-P2) gradually increases and changes from point (g) to point (h) corresponding to the maximum flow rate.

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 (Bb) 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 (Bb) for displaying the calculated flow rate. llc), for example 10 to 4. QOO/! /
This makes it possible to perform accurate measurements over a wide range of hours while keeping the differential pressure to 15 uiHzO 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 valve opening of the valve body (16) are set to approximately the intermediate value, and the flow rate measurement using the first information is free from errors 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) closes, 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.

A low differential pressure operating type on-off valve (D
), and the on-off valve (D) has a small flow path (1
3) A diaphragm (27) linked to the valve body (26) to open and close is connected to a pressure chamber (29a) communicating with the upstream side of the valve body (26) through a passage (28), and a pressure chamber (29a) connected to the downstream side of the valve body (26). A spring (30
) is provided.

In other words, if a small flow rate leak occurs on the downstream side of the flow meter when fluid transport is stopped, the downstream pressure gradually decreases and reaches the set value, and the valve body (26) opens and the first measuring section ( A), a fairly large pressure fluctuation occurs instantaneously, and a pulse signal due to the pressure fluctuation is sent to the sensor (10) of the first measuring section (A).
).

Based on the information from the sensor (10) of the first measurement part (A), a leakage detection means (31) is provided for detecting that the on-off valve is opened when fluid transport is stopped.
Alarm means (32) for notifying the occurrence of leakage according to instructions from (31)
) is provided.

Valve seat (22) and small flow path (13) of the governor valve (C)
A valve seat (33) located downstream of the outlet (13a) of
and a valve body (34) attached to the diaphragm (17) of the governor valve (C), forming an emergency shutoff valve (E). Then, in the governor valve (C), the diaphragm (
17) and the valve body (16) with a telescopic connector (35a).
(35b) and the compression spring (36) are interlocked to connect the valve body (16) of the governor valve (C) as shown in Fig. 4.
is in the fully open position, the diaphragm (17) and the valve body (34) of the emergency shut-off valve (E) are moved to close the emergency shut-off valve (IE). In addition, the emergency shutoff actuator (F) for closing the emergency shutoff valve (E) and the reset operation part (G) for opening the emergency shutoff valve (E) are configured as follows. It is.

To form the actuator (F), a diaphragm (1
A permanent magnet (37a) and a magnetic body (37b) are provided on the member (37) for pressing 7), and a spring ( 38), and the permanent magnet (3) of the pressing member (37) is provided.
7a) and a permanent magnet (4) that acts on the magnetic body (37b) of the pressing member (37).
0) to the cover (41), switch the electromagnet (39) between the energized state and the de-energized state, and set the N of the electromagnet (39).
A switching means (42) is provided for switching between the pole and south pole positions. In other words, as shown in Figures 1 and 3, under normal conditions, the permanent magnet (4) overcomes the spring (38).
0) to attract the magnetic body (37b), de-energize the electromagnet (39), hold the pressing member (37) in a non-acting position with respect to the diaphragm (17), and open the emergency shutoff valve part). It is constructed so that it can be maintained in a valve state.

Further, when the leakage detection means (31) transmits a shutoff instruction accompanying the leakage detection to the switching means (42), as shown in FIG. 4, the permanent magnet (37a) of the pressing member (37) is Electromagnet (39) so as to repel it to the (17) side.
) is energized, the attraction by the permanent magnet (40) to which the magnetic body (37b) is fixed is moved out of the possible range, and the spring (38) acts on the diaphragm (17) via the pressing member (37). The structure is such that the emergency shutoff valve (E) is closed. Then, when the cut-off release instruction is transmitted to the switching means (42) by manual operation of the input means (43),
As shown in FIG. 5, the permanent magnet (
The electromagnet (39) is energized so as to attract the diaphragm (37a), the magnetic body (37b) is attracted by the fixed permanent magnet (40), and the pressing member (37) is attracted to the diaphragm (1).
7), and the electromagnet (39) is then switched to a non-energized state.

An emergency shutoff valve (E) forms the reset operation part (G).
A bypass passage (44) is provided that communicates the upstream and downstream sides of the bypass passage ( 44), and after the pressing member (37) is returned to the non-operating position as shown in FIG.
The fluid pressure acting on the part of the spring (2
1) opens the emergency shutoff valve (E) and also opens the governor valve (
C).

[Another example]

Next, another embodiment will be described.

The specific configurations of the governor valve (C) and the low-pressure operating type on-off valve (D) can be changed as appropriate, and the on-off valve (D) may be arranged at the inlet of the first measuring section (A).

When connecting two measuring parts (A) and (B) in series, the small first measuring part (A) of the jet nozzle (3) is connected to the large second measuring part (B) of the jet nozzle (3). ) may be placed on the upstream side.

The detection method, configuration, number of sensors, etc. of the sensor (10) can be changed freely.For example, the two-station return path (7a), (7b)
A sensor (10) may be provided at. Furthermore, the device (11) for detecting and displaying meteors can also be modified in various ways.

Shutoff components such as the emergency shutoff valve (E), actuator (F), and reset operation section (G) may be omitted.

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

[Brief explanation of drawings]

Figures 1 to 6 show embodiments of the present invention, Figure 1 is an overall sectional view, Figure 2 is a sectional view taken along line u-n in Figure 1, and Figures 3 to 5 are 01 production states. FIG. 6 is a graph showing changes in differential pressure as the flow rate changes. 7th
The figure is a sectional view of a conventional example.・(2)...Pipe constriction part, (3)...Blowout nozzle, (5)...Pipe enlargement part, (6a)
, (6b)...control nozzle, (7a),
(7b)...Return flow path, (15)...
Bypass flow path, (A)...First measurement section, (1
1)...Second measuring section, (C)...Governor valve, (D)...Low differential pressure operating type on-off 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) within the set flow rate range.
) is a feedback fluidic flowmeter installed in such a way that the differential pressure (P_1-P_2) between A fluidic flowmeter in which a molded opening/closing valve (D) is configured to open only when the downstream pressure is lower than the upstream pressure by a set value or more.