KR100732117B1 - FLOW rate DETECTOR - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate detector, wherein the flow rate detector comprises a duct, a plurality of measuring flow passages provided in the duct and having various cross-sectional areas, and a vortex sensor respectively provided in the plurality of flow passages. The invention as described above can be measured in a wide range from a small flow rate to a large flow rate compared to the conventional method, in particular, there is an advantage that can be used in various applications can measure the small flow rate, which is a disadvantage of the flow sensor.

Carman Vortex, Vortex Sensor, Flow Path, Switch

Description

Flow detector {FLOW rate DETECTOR}

1 is a schematic plan cross-sectional view showing a conventional vortex detector.

Figure 2 is a cutaway perspective view of a conventional vortex detector.

3 is a cross-sectional view showing a conventional vortex detector.

4 is a schematic cross-sectional view of a flow detector according to the present invention having a parallel structure.

5 is a schematic cross-sectional view of a flow detector according to the present invention having a series structure.

                <Description of the code | symbol about the principal part of drawings>

10, 110, 111: rod 12, 112, 113, 212, 213: piezoelectric element

14: vortex 116, 216: duct

118, 120, 218, 220: Vortex sensors 122, 216: First flow path

124, 224: 2nd flow path 126, 226: switching switch

228: secondary euro

The present invention relates to a flow rate detector, and more particularly, to a structure of a flow rate detector for measuring pressure fluctuations up to micro flow rates and large flow rates using vortices.

Among the flow rate detectors that measure the flow rate of a flowing fluid, volumetric flow meters, differential pressure flow meters, area flow meters and turbine flow meters are measured while the measuring fluid provides energy to the flow measurement element, although there is a loss of energy in the form of pressure loss. The flowmeter itself is characterized by the ability to measure flow rate without receiving extra energy from the outside. In contrast, electromagnetic flowmeters, ultrasonic flowmeters, mass flowmeters, etc., in principle, there is no energy loss in the fluid itself is measured, the flowmeter itself requires a separate external energy to measure the flow rate. There are various types of fluids to be measured by the flowmeter, the measurement environment is complicated, and the measurement purposes are also various. Therefore, it can be said that it is impossible and impossible to measure all fluids with one kind of flowmeter, apply them to a complicated environment, and meet various measurement purposes. In practice, flowmeters vary in principle and have different structures. Among them, the most commonly used flowmeter is a Karman type vortex meter which measures the flow rate by using the generation of vortices.

1 is a schematic plan sectional view showing a conventional vortex detector, and FIG. 2 is a cutaway perspective view showing a conventional vortex detector. 3 is a cross-sectional view showing a conventional vortex detector.

Referring to FIG. 1, the eddy current detector is composed of a rod 10 and a piezoelectric element 12 in a fluid flow path.

The rod 10 having a predetermined shape connects the upper and lower portions of the flow path as shown in FIG. 2 and is installed in a direction perpendicular to the flow of the fluid. Although the rod 10 is illustrated in a trapezoidal shape in the drawing, a shape such as a triangular pillar may be used without being limited thereto.

The piezoelectric element 12 is also called a piezoelectric element. When mechanical force is applied, electricity is generated. Conversely, when electric force is applied, mechanical force is generated. That is, when the piezoelectric element 12 is deformed by applying an external force, a voltage is generated on the surface thereof. On the contrary, when the voltage is applied, displacement or force is generated. Such piezoelectric elements 12 include quartz, tourmaline, barium titanate, and the like, and are also used for ultrasonic generation. The piezoelectric element 12 is fixedly installed in the flow path in the downstream direction of the rod 10 at the center and is provided in the fluid passage. The piezoelectric element 12 has a cross-sectional shape extending in parallel in the longitudinal direction with respect to the flow path, and thus can be easily bent by the vortex following the rod 10. The piezoelectric element 12 can be provided in plurality.

Next, look at the operation of the vortex detector according to the prior art. When fluid begins to flow in the flow path and contacts the rod 10, as shown in FIG. 3, regular vortices 14 alternately occur on both sides, split into both sides of the rod 10. This vortex 14 is called a carman vortex. When the Karman vortex 14 hits the piezoelectric element 12, the piezoelectric element 12 is bent by deformation due to stress. The piezoelectric element 12 is deformed by the fluid and generates an electrical signal corresponding thereto. The flow rate is measured by comparing the reference voltage by an external controller not shown by this signal.

However, the conventional flowmeter has a relatively wide measurement range because the frequency through the vortex is independent of the type of the fluid, but the piezoelectric element 12 is extremely sensitive when detecting the vortex pressure in the fluid having a smaller flow rate compared to the flow path diameter. If the piezoelectric element 12 of high sensitivity is not used, it is difficult to detect. In addition, the highly sensitive piezoelectric element 12 responds sensitively to other forces applied to the piezoelectric element 12 other than the vortex pressure, such as vibration, so that the accurate measurement value only by the vortex pressure is obtained under the influence of the surroundings. There is a difficult problem.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide a flow rate detector structure for measuring various flow rates ranging from low flow rate to large flow rate.

In order to achieve the above object, the flow rate detector of the present invention comprises a duct, a plurality of measuring flow paths provided in the duct and having various cross-sectional areas, and a vortex sensor respectively provided in the plurality of flow paths. The eddy current sensor corresponds to the size of a plurality of flow paths respectively installed. The plurality of flow paths may include an open / close switch arranged in parallel and open only one flow path, and the plurality of flow paths may be arranged in series. Among the flow paths arranged in series, a flow path having a small cross-sectional area may include an auxiliary flow path arranged parallel thereto, and may include an opening / closing switch for opening and closing the auxiliary flow path.

3 is a schematic cross-sectional view of a flow detector according to the present invention having a parallel structure. Referring to the drawings, the flow rate detector includes a duct 116, a first flow passage 122 and a second flow passage 124 arranged in parallel having different cross-sectional areas in the middle of the duct, and the first flow passage and the second flow passage. On and off switch 126 for selectively opening and closing the 122, 124, the first vortex sensor 118 and the second vortex sensor 120, respectively provided in the first flow path and the second flow path (122, 124) Consists of.

The duct 116 is a cylindrical structure that forms a flow path through which a fluid flows. The duct 116 is divided into a first flow passage 122 and a second flow passage 124 having a diameter smaller than that of the first flow passage 122. The first flow passage 122 and the second flow passage 124 are connected in parallel, and the opening and closing switch 126 is provided in the first flow passage 122 and the second flow passage 124, respectively. The opening / closing switch 126 opens the second flow path 124 when the first flow path 122 is opened, and opens the second flow path 124 when the first flow path 122 is closed. The on / off switch 126 is an inlet and an outlet of the first flow path and the second flow paths 122 and 124, that is, a branch point where the first flow path 122 and the second flow path 124 branch and the first flow path 122 after the flow rate measurement. ) And the second flow path 124 are provided.

The first eddy current sensor 118 provided in the first flow passage 122 is composed of a first rod 110 and a first piezoelectric element 122.

The first rod 110 connects an upper portion and a lower portion of the first flow passage 122 and is positioned substantially at the center of the first flow passage 122 and extends perpendicularly to the first flow passage 122. In addition, the first rod 110 has a constant cross section such as a trapezoid to generate a Karman vortex, and the long side of the cross section is placed upstream, and is positioned at the position where the Karman vortex occurs, that is, downstream. The short side is located.

The first piezoelectric element 112 serving as a pressure sensor is fixed to the first flow passage 122 at a substantially center of the flow passage. The first piezoelectric element 112 can be easily bent by the Karman vortex. Thus, the Karman vortex occurring in the fluid flow can be effectively detected by the first piezoelectric element 112.

In addition, a controller (not shown) is connected to the first piezoelectric element 112 outside the flow rate detector. The controller receives the output signal of the piezoelectric element, compares the output signal from the first piezoelectric element 112 with the reference voltage generated by the reference voltage power supply, and accurately determines the flow rate of the fluid.

The second eddy current sensor 120 corresponding to the second flow path 124 smaller than the diameter of the first flow path 122 is installed. That is, the second vortex sensor 120 has the same configuration as the first vortex sensor 118, but has a size corresponding to the diameter of the second flow path 124 and the second rod 111 and the second piezoelectric element 113. It includes. In this case, the first piezoelectric element 112 and the second piezoelectric element 113 may include a piezoelectric element capable of measuring a large flow rate and a piezoelectric element capable of detecting a small flow rate, respectively, in the first flow path and the second flow path 122 and 124. It is preferable to install in.

The operation of the parallel flow detector will be described. When a large flow fluid is introduced into the flow rate detector through an inlet pipe (not shown), the fluid flows only into the first flow path 122, that is, the opening and closing switch to open the first flow path 122 and close the second flow path 124. Adjust 126. When a large flow rate of fluid flows through the first flow path 122, the Karman vortex is generated by the frictional force generated in the fluid by the first rod 110 of the first vortex sensor 118. When the first vortex sensor 118 flows near the first piezoelectric element 112, the first piezoelectric element 112 generates an electrical signal in response to the pressure fluctuation of the fluid due to the first piezoelectric element 112. . The pressure is then detected by a controller (not shown).

On the other hand, when a small amount of fluid is introduced into the flow rate detector, the fluid flows only into the second flow path 124, that is, the opening / closing switch 126 is adjusted to close the first flow path 122 and open the second flow path 124. . When a small amount of fluid flows through the second flow path 124, Karman vortex is generated by the friction force generated in the fluid by the second rod 111 of the second vortex sensor 120, and the second vortex sensor 120 The fluid flows near the second piezoelectric element 113 of the second piezoelectric element 113 to detect the pressure fluctuation of the fluid, and to detect the pressure by a controller (not shown).

By the above operation, the flow rate detector according to the present invention can measure not only a large flow rate but also a small flow rate by a plurality of measuring flow passages having various cross-sectional areas and a vortex sensor installed in each flow passage.

Although FIG. 4 illustrates the structure of a flow detector having two parallel structures, two or more parallel structures are provided by installing two or more flow paths having different flow rates and installing piezoelectric elements having a detection intensity suitable for each flow rate. It can comprise with a flow rate detector which has. This has the advantage that the measurement range from micro flow rate to large flow rate can be further extended.

5 is a schematic cross-sectional view of a flow detector according to the present invention having a series structure. Referring to the drawings, the flow detector includes a duct 216, a first flow path 222 in the duct 216, a second flow path 224 and an auxiliary portion formed in parallel to each other downstream of the first flow path 222. On-off switch for opening and closing the flow path 228, the first vortex sensor 218 and the second vortex sensor 220 provided in the first flow path 222 and the second flow path 224, and the auxiliary flow path 228. It consists of 226.

A first flow path 222 is formed at a position at which fluid flows into the duct 216, and is divided into a second flow path 224 and an auxiliary flow path 228 while passing through the first vortex sensor 218. The second flow path 224 has a smaller cross-sectional area than the first flow path 222 and has a second vortex sensor 220 having a size corresponding thereto. The opening and closing switch 226 for opening and closing the auxiliary flow path 228 is installed at the inlet and the outlet of the auxiliary flow path 228, and when the fluid flows only in the second flow path 224 when a large flow fluid flows, Since the two flow paths 224 are subjected to a high pressure, in order to prevent this, not only the second flow path 224 but also to allow the fluid to flow through each other through the auxiliary flow path 228. The configuration of the first vortex sensor 218 and the second vortex sensor 220 is as described with reference to FIG. 3.

Next, look at the operation of the flow rate detector of the serial structure according to the present invention. When a large amount of fluid is introduced into the flow rate detector through an inlet pipe (not shown), the fluid flows through the first flow path 222 and the frictional force generated in the fluid by the first rod 210 of the first vortex sensor 218. Karman vortex is generated by the gas, and when the carman vortex flows near the first piezoelectric element 212 of the first vortex sensor 218, the first piezoelectric element 212 detects the pressure fluctuation of the fluid due to the carman vortex. To generate an electrical signal. The pressure is then detected by a controller (not shown). At this time, the opening / closing switch 226 of the auxiliary flow path 228 is opened so that the fluid passing through the first flow path 222 flows into the second flow path 224 and the auxiliary flow path 228. In addition, when a small amount of fluid is introduced into the flow rate detector through an inlet pipe (not shown), the fluid flows through the first flow path 222 to the second flow path 224. At this time, the auxiliary flow path 228 is closed by the open / close switch 226 so that the fluid flows only to the second flow path 224. The Karman vortex is generated by the frictional force generated in the fluid by the second rod 211 of the second vortex sensor 220 positioned in the second flow path 224. When flowing near the second piezoelectric element 213, the second piezoelectric element 213 detects the pressure fluctuation of the fluid due to the Karman vortex and generates an electrical signal. The pressure is then detected by a controller (not shown).

Although FIG. 5 demonstrated the structure of the flow rate detector which has two series structures, it can be comprised by the flow rate detector which has two or more series structures. This has the advantage that the measuring range from low flow to large flow can be further increased.

Further, after the size of the second flow path is larger than that of the auxiliary flow path, a third vortex sensor is further installed in the auxiliary flow path to divide the flow rate into three stages to measure the flow rate in each of the first flow path, the second flow path, and the auxiliary flow path. You may.

The structure of the flow rate detector according to the present invention has been described in parallel and in series. However, the flow rate detector of the parallel structure and the flow rate detector of the series structure can be used interchangeably. In addition to vortex flow detectors, it is also applicable to electromagnetic flowmeters, ultrasonic flowmeters and mass flowmeters.

As mentioned above, the flow rate detector according to the present invention has reconstructed the structure to measure the flow rate of the fluid.

Therefore, this invention can measure a large area | region, and there exists an effect which can measure a small flow volume.

In addition, the present invention can measure a variety of flow rate at one time, there is an effect that can be used for various purposes.

Claims (5)

A duct, a plurality of measuring flow paths provided in the duct, and a vortex sensor provided respectively in the plurality of measuring flow paths, And the plurality of measuring flow passages have different cross-sectional areas. The flow rate detector according to claim 1, wherein the eddy current sensor is formed in each of the plurality of measurement flow paths and has a different size. The flow rate detector according to claim 1, wherein the plurality of flow paths further comprise an open / close switch arranged in parallel to open only one measuring flow path. The flow rate detector of claim 1, wherein the plurality of measurement flow paths are arranged in series. The flow rate detector according to claim 4, wherein at least one of the measuring flow paths further comprises an auxiliary flow path arranged in parallel therewith and an opening / closing switch for opening and closing the auxiliary flow path.

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