JPS61292521A - Vortex flowmeter - Google Patents

Abstract

PURPOSE:To sensitively measure a low flow rate and enlarge a flow rate measuring range by arranging a pair of sensors in the longitudinal direction of a piping. CONSTITUTION:A differential pressure due to a Karman's vortex generated on the downstream side of a vortex generator 3 in accordance with the flow rate of a fluid to be measured flowing in a passage 2 is introduced from the eddy differential pressure introducing openings 4a and 4b of the vortex generator 3 into lead chambers 7a and 7b through the introducing openings 7c and 7d of a lead member 7. Thus, metallic diaphragms 9a and 9b are differentially displaced, accompanying the movement of a sealed liquid 13. The displacement of the diaphragms 9a and 9b is detected as a change in the electrostatic capacity of electrode plates 11a and 11b and a flow rate measurement signal is produced from a flow rate detector 5. Since a pair of sensor portions 6a and 6b are arranged in a longitudinal direction, even when an oscillation is generated in a piping 1 and in a horizontal direction perpendicular to the longitudinal one direction, the sealed fluid 13 is prevented from moving between the sensor portions 6a and 6b due to the oscillation and the diaphragms 9a and 9b are prevented from the displacement due to the oscillatory motion of the sealed fluid 13, enabling the output of a false signal due to the oscillation to be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vortex flow meter, and more particularly to a vortex flow assembly 1 installed in a pipe for feeding fluid and measuring the flow rate of a fluid.

Conventional technology In general, a vortex flow meter has a vortex generation column installed in a piping flow path, and pressure changes due to Karman vortices that are generated alternately downstream of this vortex generation column are detected through pressure introduction holes from both sides of the vortex generation column. 1 through
The flow rate in the piping flow path is measured by leading to the ffi detection section. In addition, the flow rate detection unit that outputs a flow rate measurement signal based on the vortex differential pressure caused by the generation of Karman vortices was configured to be directly fixed to the outer circumference of the pipe.

When installed in piping and used in this way, in an electrostatic capacitive vortex flow meter, the flow rate detection part consists of a pair of metal diaphragms that are displaced by the differential pressure on both sides of the vortex generation column, and an insulating material is attached to the metal diaphragm. It has a pair of sensor portions consisting of electrode plates facing each other with the electrode plates interposed therebetween. In addition, the pair of metal diaphragm chambers provided with the metal diaphragm and the electrode plate are communicated via a communication path, and the differential pressure caused by the generation of the vortex is reduced by the difference I.
It was designed to perform JJ-like detection and to seal in a liquid to withstand the pressure of the fluid in the piping.

Problems that the invention aims to solve However, vibrations occur in the piping due to the transfer of fluid in the piping flow path, and the vibrations from the piping are also transmitted to the flow detection unit that is directly fixed to the piping. , the flow detection section performed flow ffi fit measurements while receiving vibrations from the piping.

Generally, a pair of hinge portions for detecting the differential pressure caused by vortex generation are provided in a horizontal direction perpendicular to the longitudinal direction of the pipe. However, as vibrations transmitted through the pipes, vibrations in the longitudinal direction of the pipes tend to occur, and even if they occur, they are relatively small;
The vibration components in the horizontal and vertical directions perpendicular to the longitudinal direction of the pipe are relatively large. For this reason, traditional vortex flowmeters
Since the pair of sensor parts are installed in the horizontal direction perpendicular to the longitudinal direction of the pipe, when horizontal vibration occurs in the pipe, the sealed liquid filled in the diaphragm chamber and communication passage of the pair of sensor parts moves horizontally. move. Therefore, in conventional vortex flowmeters, the horizontal vibration of the piping causes the sealed liquid to be accelerated between the pair of sensor parts, and the inertia of the sealed liquid causes the metal diaphragm to be displaced. Furthermore, there is a drawback that a change in capacitance is detected due to the displacement of the metal diaphragm due to such piping vibration, and a Te signal is output.

In addition, it is possible to measure minute flow rates with small displacement of the metal diaphragm.
However, it is not possible to determine whether the metal diaphragm was displaced due to the differential pressure caused by the Karman vortex or whether the metal diaphragm was displaced due to piping vibration.

Therefore, when measuring a low flow rate, it is necessary to reduce the amplification sensitivity of the electric circuit to such an extent that changes in capacitance due to displacement of the metal diaphragm due to pipe vibration are not detected. For this reason, it is not possible to measure the microflow m in which the displacement of the metal diaphragm is small due to the generation of the Karman vortex, resulting in a disadvantage that the range of visual flow rate measurement becomes narrow.

Therefore, an object of the present invention is to provide a vortex component 1 that eliminates the above-mentioned drawbacks.

Means and Function for Solving the Problems The present invention provides a vortex flowmeter having the above-mentioned structure, in which the pair of sensor sections are disposed along the direction of force applied to the piping. The structure is oriented to withstand the effects of vibration, allowing for sensitive measurement of low flows and expanding the range of visual flow measurements.

Embodiment FIGS. 1 and 2 show an embodiment of the vortex flowmeter according to the present invention. In FIG. 1, a flow path 2 in a pipe 1 is provided with a vortex generator 3 of a vortex flowmeter. The vortex generator 3 has a flow path 2 on both sides.
It has vortex differential pressure introduction holes 4a and 4b that communicate with.

5 is a flow m detection part of a vortex flowmeter, and a capacitance type sensor part 6a
, 6b, and is provided on a pressure guiding member 7 fixed to the upper surface 1a of the pipe 1. A pair of sensor parts 6
a and 6b are arranged along the longitudinal direction of the pipe 1. The pressure guiding member 7 has pressure guiding chambers 7a, 7b spaced apart in the longitudinal direction of the piping 1 on the upper surface, and a pressure guiding hole 7c communicating the pressure chambers 7a, 7b with the vortex differential pressure introduction holes 4a, 4b. 7d.

The senna section 6a consists of a metal diaphragm 9a provided below the diaphragm chamber 8a, and an electrode plate 11a provided on the insulator 10a above the diaphragm chamber 8b. Further, the sensor section 6b has the same configuration as the sensor section 6a,
It consists of a metal diaphragm 9b and an electrode plate 11b. The metal diaphragms 9a and 9b are the pressure guiding chambers 7a of the pressure guiding member 7.
.

It faces 7b. Therefore, the metal diaphragm 9a
, 9b are displaced in accordance with the vortex differential pressure introduced into the pressure guiding chambers 7a, 7b via the pressure guiding holes 7c, 7d.

Reference numeral 12 denotes a communication path for differentially detecting the vortex differential pressure, which includes a pair of diaphragm chambers 8 separated from each other in the longitudinal direction of the pipe.
It is provided to communicate between a and 8b. The communication passage 12 and the pair of diaphragm chambers 3a, 8b are filled with an incompressible liquid 13 such as silicone oil.

As shown in FIG. 2, the vortex differential pressure introduction holes 4a and 4b provided on both sides of the vortex generator 3 are bent in the vertical direction, and the n through hole lb of the pipe 1 bored in the vertical direction, It is connected to 1c. The through holes 1b and 1c are pressure guiding holes 7c and 7 of the pressure guiding member 7.
Diaphragm ff8a that connects metal diaphragms 9a, 9b via d.

8b.

Therefore, the differential pressure due to the Karman vortex generated on the downstream side of the vortex generator 3 in accordance with the flow rate of the fluid to be measured flowing in the flow path 2 is transferred to the vortex differential pressure introduction hole 4a of the vortex generator 3.

4b is introduced into the pressure guiding chambers 7a, 7b via the introduction holes 7c, 7d of the pressure guiding member 7. This causes the metal diaphragm 9a to move as the sealed liquid 13 moves.

9b is differentially displaced. Metal diaphragm 9a.

The displacement of 9b is detected as a change in the capacitance of electrode plates 11a and 11b, and the flow rate detection section 5 outputs a flow rate measurement signal.

Here, a case will be described in which vibration occurs in the pipe 1 and the vibration of the pipe 1 is transmitted to the flow rate detection section 5 via the pressure guiding member 7. In comparison, vibrations in the horizontal direction perpendicular to the longitudinal direction are likely to occur in the pipe 1. When this horizontal vibration is transmitted to the flow rate detection unit 5, the sealed liquid 13 in the diaphragm chambers 8a, 8b and the communication passage 12 is divided into the pair of diaphragm chambers 8a and 8.
It receives acceleration in the horizontal direction perpendicular to the direction connected to b.

Therefore, the horizontal vibration causes the filled liquid 13 to flow into the communication path 1.
The metal diaphragm chambers 9b are not displaced by moving between the pair of diaphragm chambers 8a and 8b via the metal diaphragm chambers 8a and 8b.

Furthermore, when vibration in the vertical direction orthogonal to the longitudinal direction of the pipe 1 is transmitted to the flow rate detection unit 5, the pair of diaphragm chambers 8
The sealed liquid 13 in the diaphragm chamber 8a and 8b receives acceleration upward and downward.

There is no need to move between 8b.

In this way, the flow Φ detection unit 5 detects the flow in the piping 1 where the flow is relatively likely to occur.
Due to the effects of vibration in a direction perpendicular to the longitudinal direction of the metal diaphragms 9a and 9b, the metal diaphragms 9a and 9b are prevented from being displaced and outputting a signal.

Note that when vibrations along the longitudinal direction of the pipe 1 are transmitted to the flow rate detection unit 5, the sealed liquid 13 is transmitted to the pair of diaphragm chambers 3a via the communication path 12.

Although there is a possibility that the pipe 1 may move between the pipes 8b and 8b, vibration in the longitudinal direction of the pipe 1 hardly occurs and can be ignored.

Therefore, the flow rate detection unit 5 can accurately detect the flow rate regardless of pipe vibration. In particular, when measuring a minute flow rate, the flow rate detection section 5 does not have to output an erroneous signal caused by pipe vibration, and the flow rate measurement in a low flow rate region can be performed accurately.

That is, there is no need to reduce the width sensitivity of the electric circuit (7) 11'1, and flow rate measurement can be performed in the low flow ω region or in a wide range.

In the above description, the flow rate detection section 5 is provided in the pipe 1 via the pressure guiding member 7, but the pressure guiding member 7 may be omitted. For example, as shown in FIG. 3, the vortex differential pressure introduction hole 14 of the vortex generating column 14
a, 14b are inclined, and vertical introduction holes 14C, 14d communicating with the vortex differential pressure introduction holes 14a, 14b are provided in hanging positions facing the metal diaphragms 9a, 9b of the flow rate detection section 5, and the introduction holes 14c, 14d Metal diaphragm 9 communicates with
a.

A pressure guiding chamber facing 9b may be provided on the upper surface 1a of the pipe 1.

Effects of the Invention As described above, according to the eddy current darkness detection according to the present invention, since the pair of sensor sections are arranged along the longitudinal direction of the pipe,
Even if vibration occurs in the horizontal direction perpendicular to the longitudinal direction, it is possible to prevent the filled liquid from moving between the pair of sensor parts due to the vibration, and to prevent displacement of the metal diaphragm due to the movement of the filled liquid. It is possible to prevent erroneous signals from being output. In addition, by adopting such a vibration-resistant structure, it is possible to improve the reliability of flow rate measurement, and it is also possible to distinguish whether the flow rate measurement signal is output due to vortex generation or pipe vibration during low flow suspension measurement. It has features such as being able to accurately measure the flow rate in a low flow rate range without the inconvenience of not being able to do so, and being able to measure the flow rate over a wide range, even down to minute flow rates.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view for explaining one embodiment of the vortex flowmeter according to the present invention, FIG. 2 is a cross-sectional view of the vortex flowmeter and piping shown in FIG. 1 as viewed from the longitudinal direction of the piping, and FIG. The figure is a plan view of a vortex generator according to a modified example of the present invention. DESCRIPTION OF SYMBOLS 1... Piping, 3.14... Vortex generating column, 5... Flow rate detection part, 6a, 6b... Sensor part, 7... Pressure guiding member, 8a. 8b...Diaphragm chamber, 9a, 9b...Metal diaphragm, 12...Communication path, 13...Sealed liquid. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A vortex generator having a pair of introduction holes provided in a flow path of piping and introducing a pressure difference due to vortex generation, a diaphragm part that is displaced according to the pressure difference from the pair of pressure difference introduction holes, and the diaphragm part. A vortex flowmeter comprising a pair of sensor sections comprising a detection section for detecting displacement of the sensor section, and a communication passage filled with a sealed liquid that communicates between the diaphragm chambers of the pair of sensors. A vortex flowmeter characterized in that the vortex flowmeter is arranged along the longitudinal direction of the piping.