KR900006407B1 - Spriral flow meter - Google Patents

Abstract

a flow passage through which a measuring fluid flows, a bluff body arranged in the flow passage for generating Karman vortex of the measuring fluid which flows through the flow passage, the bluff body being provided with a pair of differential pressure introducing holes for introducing a pressur change caused by the generation of the Karman vortex of the measuring fluid, the differential pressure introducing holes opening to respective side surfaces of the bluff body and extending toward and penetrating through one end of the bluff body; a main detecting part body which is an independent member from the bluff body; a pair of detecting parts provided in the main detecting part body, the pair of detecting parts comprising a pair of recesses provided on the main detecting part body.

Description

Eddy flowmeter

1 is a rear view of a first embodiment of the swirl flow meter of the present invention.

2 is a longitudinal side view of the vortex flowmeter of FIG.

3 is a transverse plan view along line III-III of the vortex flowmeter of FIG.

4 is a circuit diagram of a detection circuit used in the vortex flow meter of FIG.

5 is a cross-sectional plan view of another embodiment of a vortex generating column.

Figure 6 is a longitudinal rear view of a second embodiment of the present inventors flow rate.

7 is a schematic plan view of the detector of the vortex flowmeter of FIG.

8 is a longitudinal side view of the swirl flow meter of FIG.

9 is a circuit diagram of a detection circuit used in the vortex flowmeter of FIG.

10 is a schematic plan view of another embodiment of the detector.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex flowmeter, particularly to a vortex flowmeter which is installed in a fluid flow path to simplify the configuration of vortex generation that generates Karmann vortices in the fluid to be inspected and does not deteriorate the measurement accuracy even in the presence of pipe vibration. It is about.

Conventionally, a vortex flow meter which forms a vortex generator in the flow path, detects a pressure change corresponding to the Cayman vortex generated in the downstream side fluid by the vortex generator, and detects the flow velocity and flow rate of the side fluid. Has been put to practical use.

In the conventional vortex flowmeter, the capacitive detection unit is provided with recesses on both sides of the vortex generator, a fixed electrode plate is provided thereon, and at the same time, the electrode receives a change in the pressure of the fluid to be spaced at a small interval. The diaphragm was provided as an electrode, and the liquid was enclosed in the space between an electrode plate and a diaphragm, and a pair of space was connected, and the sealing liquid was enclosed. In this vortex flowmeter, a carman vortex is generated in the side fluid passing through both sides of the vortex generator as the flow of the side fluid flows, and a pair of diaphragms are displaced in response to the pressure change, and the diaphragm and the fixed electrode The flow rate is detected by electrically detecting that the capacitance between them changes.

However, the piping generates vibration due to the transfer of the fluid in the piping flow path. The vibration is transmitted from the piping to the flow rate detection section fixed directly to the pipe, and the flow rate detection section performs the flow measurement while receiving the vibration from the pipe.

Generally, a pair of sensor part which detects the differential pressure by vortex generation is provided in the horizontal direction orthogonal to the longitudinal direction of piping. However, the vibration in the pipe length direction is unlikely to occur as a vibration for transmitting the pipe, and although relatively small, the vibration component in the horizontal and vertical directions orthogonal to the pipe length direction is relatively large. For this reason, in the conventional vortex flowmeter, a pair of sensor portions are provided in a horizontal direction perpendicular to the pipe length direction. Therefore, if vibration in the horizontal direction occurs in the pipe, the pair of sensor portions is filled in the diaphragm chamber and the communication path. The liquid swings in the horizontal direction.

Therefore, in the conventional vortex flowmeter, since the vibration in the horizontal direction of the pipe occurs, the encapsulating liquid receives an acceleration in a pair of sensor portions, and the metal diaphragm is displaced by the completion of the encapsulating liquid.

In this case, there is a drawback that a change in capacitance is detected by the displacement of the metal diaphragm due to the pipe vibration, and a signal is output.

In addition, when measuring a small flow rate with small displacement of the metal diaphragm, it is not possible to determine whether the metal diaphragm is displaced by the differential pressure caused by the carman vortex or whether the metal diaphragm is displaced by the pipe vibration. Therefore, when measuring the low flow rate, it is necessary to reduce the amplification sensitivity of the electric circuit which makes it impossible to detect the change in capacitance caused by the bias of the metal diaphragm due to the pipe vibration.

Therefore, there is a drawback that the small flow rate of the metal diaphragm caused by the generation of the carman vortex cannot be measured and the flow rate measurement range is narrowed. Thus, the present invention provides a novel and useful eddy flowmeter which eliminates the above-mentioned drawbacks, and each embodiment will be described as follows.

The swirl flow meter 10 as the first embodiment of the swirl flow meter according to the present invention shown in FIGS. 1 to 3 has a conduit 11 having a substantially flange and a vortex generated in a direction perpendicular to the center of the pipeline 1 l. A detection unit 13 provided above the column 12, the vortex generating column 12 outside the pipeline 11, and a detection circuit described later electrically connected to the detection unit 13.

Differential pressure introduction openings 14a and 14b are respectively opened in the upper middle portions of both side surfaces 12a and 12b of the vortex generating column 12. In communication with the openings 14a and 14b, the differential pressure introduction platings 15a and 15b extend inwardly in the vortex generating column 12. As shown in FIG. It is sufficient that the openings 14a and 14b are symmetrically provided in the vortex generating column 12, and the rigidity of the hole mounting accuracy of the differential openings 15a and 15b of the catches 14a and 14b is sufficient. It is not required and the vortex generating column 12 can be manufactured at low cost. The upper part of the vortex generator 12 penetrates the pipe wall of the pipe line 11.

Between the pipe wall outer periphery of the pipe line 11 and the detection unit 13, the introduction hole forming member 16 is formed with inclined differential pressure introduction holes 17a, 17b communicating with the differential pressure introduction holes 15a, 15b. In addition, circular recesses 18a and 18b for opening the differential pressure introduction holes 17a and 17b are provided on the upper surface thereof. The detection part 13 is attached on the member 16.

In the detection unit 13, stainless diaphragms 19a and 19b are provided to face the recesses 18a and 18b as circular movable electrodes, and the diaphragms 19a and 19b. The electrode 21a, 21b like the conductive foil is provided as a circular fixed electrode with space 20a, 20b between them.

The spaces 20a and 20b pass through the electrodes 21a and 21b to communicate with the communication path 22. The spaces 20a and 20b are non-compressible in the spaces 20a, 20b and the communication holes 22. Fluid, eg, liquid 23, such as silicone oil, is enclosed.

The diaphragm 19a and the electrode 21a form a variable capacitor 24a as a sensor unit, and the variable capacitance capacitor as a sensor unit different from the diaphragm l9b and the electrode 21b ( 24b) is formed.

Lead wires (not shown) connected to the variable capacitors are introduced into the electrical circuit receiving cases (not shown) through the pipe 25 and connected to the detection circuits. The condenser 24a, 24b is mutually arrange | positioned in the direction which extends to the longitudinal direction of the conduit 11, and the opening 11a which is interposed in the direction orthogonal to the longitudinal direction of the conduit 11 is provided. Sloped differential pressure cavities 17a and 17b are provided to introduce the differential pressures from and 11b into the recessed portions l8a and 18b which are interposed in the longitudinal direction of the conduit 11. .

The coils 3l and 32 forming the bridge circuit 30, such as the capacitors 24a and 24b, provide the outputs of the AC power supply 33 and the bridge circuit 30 to supply AC to the bridge circuit 30. An amplifying circuit 34, a demodulation circuit 35 and a chute circuit 36 for amplifying are provided. From the Schmitt circuit 36, a pulse signal having a repetition frequency proportional to the flow rate of the fluid to be measured is output, and supplied to the subsequent circuit from the output terminal 37.

In the vortex flowmeter 10 having the above-described configuration, when the fluid to be flowed through the conduit 11 in the F direction, the Cayman vortex 26 is formed on both sides 12a and l2b by the vortex generating column 12. It is generated alternately as shown in the figure. At this time, the pressure on the side where the carman vortex is generated also decreases and the pressure on the side where the carman vortex does not occur increases.

Therefore, the pressure on the side where the carman vortex is generated (for example, the side surface 12a) and the pressure on the side where the carman vortex does not occur (for example the side surface 12b) are the openings 14a, the differential pressure introduction holes 15a, and 17a. The diaphragm is guided to one side of the diaphragm 19a via the diaphragm 19a or through the opening 14b, the differential pressure introduction holes 15b, 17b, and the recessed portion 18b. 19a displaces downward and the diaphragm 19b displaces upward.

As a result, when the fluid to be flowed, the carman vortices are mutually generated by the vortex generating column 12 on both sides thereof as shown in FIG. 3, whereby the opposite surfaces 12a and 12b have the reverse phase When pressure is generated, the pressure change in the reverse phase of the side fluid is diaphragm through the openings 14a, 14b, the differential pressure introduction holes 15a, 15b, 17a, 17b, the recesses 18a, and 18b. It is introduced to one side of (19a) and (19b). The diaphragms 19a and 19b receive this pressure change and are displaced up and down with each other in the reverse phase, whereby the capacity of the condenser 24a is increased and decreased, and the capacity of the condenser 24b is also increased. The period of the capacitance change of the capacitors 24a and 24b corresponds to the generation period of the vortex 26 and is inversely proportional to the flow rate.

Accordingly, the bridge circuit 30 generates an output obtained by amplitude-modulating the signal of the AC power supply 33 in proportion to the flow rate, and a pulse signal having a repetition frequency proportional to the flow rate is output from the Schmitt circuit 36. By measuring the period of the output signal or the number of output signals, the flow velocity or the flow rate can be obtained.

Here, when external vibration is applied to the pipe line 11, the detection part 13 also vibrates together.

However, as described above, the vibration applied to the conduit 11 is more frequent in the longitudinal direction than the vibration in the longitudinal direction of the conduit. However, as described above, the variable capacitance capacitors 24a and 24b of the detection unit 13 are arranged in parallel in the longitudinal direction of the conduit 11, and the space 20a of both variable capacitance capacitors 24a and 24b. The communication hole 22 which bundles 20b and encloses the sealing liquid 23 extends in the longitudinal direction of the conduit 11. Therefore, even if the conduit 11 vibrates in the longitudinal direction, and the sealing liquid 23 vibrates in the same manner, the pressure change due to the vibration of the sealing liquid 23 is not applied to the diaphragms 19a and 19b.

In addition, even if the pressure change due to the vibration of the encapsulating liquid 23 is applied to the diaphragms 19a and 19b, they are in the same phase so that they do not cancel each other and produce an incorrect detection output.

Further, in the above embodiment, the member 16 having the inclined differential pressure introduction holes 17a and 17b to communicate with the recesses 18a and 18b which are interposed in the longitudinal direction of the conduit 11 is provided. Although used, the member 16 may be omitted by using the vortex generating column 40 whose cross section is shown in FIG. In this case, in the vortex generating column 40, the holes 41a and 41b extending in opposite directions from the openings 14a and 14b on both sides, and the holes 42a extending upward in the vertical direction from the groove portions thereof. (42b) are open.

Holes 42a and 42b are interposed in the longitudinal direction of the conduit 11, and recesses 18a and 18b are interposed in the longitudinal direction of the conduit 11 as shown in FIG. Salary intact.

Next, a second embodiment of the vortex flow meter of the present invention will be described with reference to FIGS.

As mentioned above, although the vibration in the longitudinal direction of the pipeline hardly occurs among the vibrations of the pipeline, the vibration in the direction perpendicular to the longitudinal direction of the pipeline tends to occur, but the vibration in the pipeline length direction is also somewhat. In the first embodiment, since a pair of variable capacitors are arranged along the longitudinal direction of the pipeline, there is a problem that the measurement accuracy decreases when there is vibration in the longitudinal direction of the pipeline.

In the second embodiment, not only the vibration in the direction perpendicular to the longitudinal direction of the conduit but also the vibration in the longitudinal direction of the conduit are prevented from decreasing the measurement accuracy. The structure of the variable capacitor as a sensor part like the metal diaphragm as the movable electrode and the fixed electrode facing the space, and the space of each pair of variable capacitors communicate through the communication path, Since it is the same as the above embodiment, its detailed description is omitted. In the swirl flow meter 50 of this embodiment, the configuration of the detection unit 51 is different from that of the above embodiment.

The introduction hole forming members 52 provided on the outer wall of the conduit 11 respectively interlock with the differential pressure introduction holes 15a and extend to the differential pressure introduction holes 53a and 53b and the differential pressure introduction holes 15b which are inclined substantially in opposite directions. The differential pressure introduction holes 53a and 53b which communicate with each other and inclined substantially in opposite directions are provided. The differential pressure introduction holes 53a and 53b intersect in three dimensions. On the upper surface of the member 52, recessed portions 54a and 54b of the differential pressure introduction holes 53a and 53b are provided.

As shown in FIG. 7, the recesses 54a and 54b for introducing the same differential pressure through the differential pressure introducing holes 15a through the differential pressure introducing holes 53a and 53b are formed in the flow direction F of the liquid. The recesses 54b and 54c which are disposed opposite to the left front and the right back and introduce the same differential pressure from the differential pressure introduction hole 15b through the differential pressure introduction holes 53b and 53c are located at the right front and the left rear. Excreted.

An attachment member 56 is attached to the member 52, and variable capacitors 55a to 55d are provided on the lower surface of the attachment member 56 to face the recessed portions 54a and 54b, respectively. Here, l pairs of variable capacitors 55c and 55d arranged side by side in a direction orthogonal to the longitudinal direction of the pipeline (same as the flow direction F of the fluid) are movable electrodes, fixed electrodes, and a space therebetween. Is communicated through the communication path 58, and the liquid is filled therebetween. Similarly, the spaces of the other pairs of variable capacitors 55a and 55b which are arranged side by side are also communicated through the communication path 57 filled with the liquid.

These capacitors 55a-55b are connected as shown in FIG. As apparent from the fertilizers of Figs. 4 and 9, parallel circuits of the condenser 55a and 55c of the bridge circuit combined with the coils 31 and 32, which correspond to the condenser 24a of Fig. 4, The parallel circuit of the capacitor | condenser 55b and 55c of the side corresponding to the capacitor | condenser 24b is connected.

The differential pressure due to the Cayman vortex generated downstream of the vortex generating column 12 corresponds to the flow rate of the fluid to be flowed in the conduit 11 at the flow rate 개구 side. 14b), through the differential pressure introduction holes 15a, 15b, 53a, and 53d, they are introduced into the respective recessed portions 54a and 54d. Here, the same differential pressure as that of the recessed portion 54a is introduced, and the same differential pressure is also introduced to the recessed portions 54b and 54c.

Therefore, if the capacitances of the capacitors 55a and 55b increase and decrease together due to the differential pressure change, they become in phase with this and the capacitances of the capacitors 55b and 55c increase and decrease together.

In the vortex flow meter 50 of the above-described configuration, a case in which pipe vibration occurs and vibration is transmitted to the detection unit 51 will be described.

First, since the communication paths 57 and 58 extend in a direction orthogonal to the Z direction with respect to the case where the detection unit 51 is vibrated in the arrow Z direction along the longitudinal direction of the pipe line 11, the communication path 57 ), 58 and the encapsulating liquid filled in the spaces of the condensers 55a-55d are not subjected to acceleration such as displacing the respective diaphragms.

Therefore, even if there exists the vibration of this Z direction, a measurement precision does not fall.

Next, when the flow rate detection unit 51 vibrates in the vertical and vertical directions (the arrow Y direction in Fig. 6) orthogonal to the longitudinal direction of the conduit 11, the diaphragm as the movable electrode of each condenser 55a-55d Each is driven in the same Y direction, and the displacement caused by the diaphragm observing force becomes the same phase.

The capacitance change in the same phase of the capacitors 55a to 55d is turned off in the bridge circuit 60. Therefore, even if the vibration in the Y direction occurs, the measurement accuracy does not decrease.

Next, the case where the flow rate detection part 51 vibrates in the horizontal direction (arrow X ₁ X ₂ direction in FIG. 6) orthogonal to the longitudinal direction of the pipe line 11 is demonstrated. When the vibration component in the direction of the arrow X ₁ acts on the flow rate detection unit 51, the encapsulating liquid in the communication paths 57 and 58 receives acceleration in the X ₂ direction relatively.

For this reason, the inertial force of the encapsulating liquid acts on the spaces of the capacitors 55a and 55c on the left side, and the diaphragm is displaced in the direction interposed from the fixed electrode. In addition, it is displaced in a direction close to the fixed electrode of the diaphragm of the capacitors 55b and 55d on the right side.

For this reason, while the capacitances of the capacitors 55a and 55c decrease, the capacitances of the capacitors 55b and 55d increase. Therefore, in the bridge circuit 60 of FIG. 9, the capacitance of one capacitor 55a of the parallel circuit decreases and the capacitance of the other capacitor 55a increases. As the capacitance of 55b increases, the capacitance of the other capacitor 55c decreases, so that the capacitance change of the capacitors 55a, 55d, 55b, 55c is turned off.

Thus, even if the flow rate detection part 51 is displaced in the direction of arrow X ₁ by the pipe line vibration, the balance of the bridge circuit 66 does not collapse, and a signal is not output from the bridge circuit 20.

The same applies to the case where the vibration component in the direction of the arrow X ₂ of the pipeline vibration acts on the flow rate detection unit 51, and the balance of the bridge circuit 60 is maintained so that a false detection signal is not output.

In this way, the vortex flowmeter 50 of this embodiment does not output a false detection signal due to the influence of the vibration even in any direction of vibration, and can accurately measure the flow rate.

In addition, since the bridge circuit 60 does not output the false detection signal due to the pipeline vibration, the gain of the amplification circuit 34 can be raised, and flow measurement can be accurately and extensively carried out to a low flow rate region.

In addition, since two pairs of sensor sections 55a, 55b, 55c, and 55d are provided, the other sensor section (55a, 55b) fails even if one sensor section (55a, 55b) fails. 55c) and 55d are used for emergency flow measurement.

Therefore, it is advantageous in terms of maintenance that the gap until repair can not be stopped.

In the above embodiment, the differential pressure introduction holes 15a and 15b are branched to communicate with the differential pressure introduction holes 53a and 53d, respectively. Four differential pressure introduction holes communicating with (53d) separately may be provided on the vortex generating column.

A detection unit 51A as another embodiment of the detection unit 51 is shown in FIG. In this embodiment, instead of the vortex generating column 12, the vortex generating column 40 shown in FIG. 5 is used. The pair of recesses 54a and 54b are disposed left front and right behind the flow direction F of the fluid, and the other pair of recesses 54c and 54d are condenser 55c. ), And 55d are disposed at the left rear and right front.

The spaces of the condensers 55a and 55b communicate with each other as the communication path 57 in which the liquid is enclosed, and the spaces of the condensers 55c and 55d communicate with the communication path 58 in which the liquid is enclosed. Here, the communication paths 57 and 58 intersect in three dimensions. The recessed portions 54a and 54b which are arranged side by side in the orthogonal direction opposite to the pipe length direction communicate with the differential pressure introducing holes 70a and 70d communicating with the differential pressure introducing holes 41b and 42b. .

The recessed portions 54b and 54c communicate with the differential pressure introduction holes 70b and 70c in communication with the differential pressure introduction holes 41a and 42b. Also in this structure, the same effect as the case of the detection part 51 is acquired.

Claims (6)

Carman vortex is generated in the pipe 11 of the fluid to be flowed and flows through the pipe, and it opens to both sides and extends through one side to introduce pressure change according to the generation of carman vortex of the fluid. In the vortex generating column 12 and the detector main body 13 through which a pair of differential pressure introducing holes 15a and 15b are drilled, and the vortex flowmeter formed therefrom, differential pressure introduction is provided between the detector main body in the longitudinal direction. A vortex flow meter having at least one pair of sensor parts (24a, 24b) for outputting a flow measurement signal in response to a differential pressure from a ball. 2. The pair of sensor portions according to claim 1, wherein the pair of sensor portions have a pair of recesses (18a) and (18b) drilled through the detector main body, and a pair of fixed electrodes (21a) and (21b) fixed to the recesses, and the fixed electrodes and the predetermined intervals. Communication between the pair of movable electrodes 19a, 19b provided between the pair of movable electrodes 19a, 19b and the pair of fixed electrodes and the movable electrodes, with the spaces 20a, 20b interposed therebetween. Ball 22, and a sealing liquid 23 filled in a pair of spaces and communication holes, the movable electrode of which is opposite to the surface of the sealing liquid, on the opposite side of the fluid being introduced by the vortex generator. And a pair of fixed electrodes and a pair of movable electrodes form a pair of variable capacitors, and a signal is outputted from the detection circuit 30 in accordance with the capacitance of the variable capacitor of the pair of sensors. Eddy flow meter. The other pair of sensors according to claim 1, wherein the pair of sensor units 55a and 55b are provided in the longitudinal direction of the conduit, and the pair of other sensors provided in the longitudinal direction of the conduit next to the pair of sensor sections. Each of the sensor units includes a variable capacitor having a fixed electrode or the like installed in a space filled with a liquid between the diaphragm as the movable electrode and the diaphragm, and one of the differential pressure introducing holes is one of two sensors. Each of the parts communicates with one sensor unit and the diaphragm to introduce a differential pressure, and the other of the differential pressure introduction holes communicates with each other to introduce a differential pressure to the diaphragm with one sensor unit. And a communication path filled with a liquid to fill the space between any one of the above-described sensor units of the pair and another sensor unit of the other pair, and the other sensor unit of the pair And the other pair of the above-mentioned flow meter wahyeong one space to the sensor unit characterized in that a soft tonghayeoseo as one of the communication path is filled with liquid. 4. The swirl flow meter according to claim 3, wherein each of the communication paths (58) and (57) extends in parallel in the direction orthogonal to the longitudinal direction of the pipe. 4. The vortex flow meter according to claim 3, wherein each communication path is three-dimensionally intersected in a " + " shape inclined in the longitudinal direction of the conduit. The variable capacitor as a sensor unit which communicates with one of the differential pressure introducing holes and introduces the same differential pressure is connected in parallel to form a first parallel connection, and the same differential pressure is communicated with the other of the differential introducing holes. And a second parallel connection, wherein the first and second parallel connections are bridged with a coil to form a detection circuit, respectively.

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