KR20050026307A - Five-sensor conductivity probe - Google Patents

Abstract

A five-sensor conductivity probe is provided to obtain an exact measurement data by spacing the ends of the sensors with a predetermined interval. A five-sensor conductivity probe includes a probe body(3) in a tube shape, a connector(5) include in an end part of the body(3), and a sensing part(7). The sensing part(3) includes three vertexes in a regular triangle and five sensors arranged in the inner part of the regular triangle. The length of one face of the regular triangle corresponds to 1.0mm. The sensors include a thin iron will. Gold plated film is coated on the surface of the thin iron will. The sensing part(7) has a hollow at the center of the sensing part(7). The sensing part(7) is inserted into a position in which flowing is measured.

Description

Five-sensor conductivity probe

The present invention relates to a probe for measuring flow factors such as bubble rate, bubble velocity, or interfacial area of a fluid flow. More specifically, the interfacial area of each phase can be effectively measured in various abnormal flows in which a gas phase and a liquid phase exist together. To a probe that has five sensors inside.

In general, the interfacial surface area of a fluid is obtained through a mathematical transformation using the velocity measured at a local point. As described above, a probe having a plurality of sensors is used to measure the interface area. As such a probe, a double sensor probe or a four sensor probe has been utilized as the number of sensors included therein.

Here, the double sensor probe method is a methodology developed on the assumption that the bubble is spherical, and it is difficult to apply in general flow conditions that violate this bubble type assumption, and the four sensor probe method has no limitation on the bubble shape, but four sensors It is difficult to effectively measure small bubbles that do not pass more than one of them. In particular, the existing four-sensor probe has a design characteristic of inserting an electrically insulated wire into the tube, so there is a limit in minimizing the cross-sectional area of the probe sensing unit, there is a problem that can not reduce the frequency of the bypass bubble. If the frequency of bypass bubbles is large, it is difficult to accurately measure the interfacial area.

The present invention has been proposed to solve the problems of the conventional sensor probe as described above, even if the bubble does not pass through one or more of the sensor does not occur or minimize the measurement error, and minimizes the measurement cross-sectional area of the sensing unit and At the same time, it is not only to obtain accurate measurement data by precisely manufacturing the gap between the sensor tips, but also to increase the strength and electrical conductivity of the sensor so that it can be used in various abnormal flows, especially high speed flow conditions.

In order to achieve the above object, the present invention is a probe consisting of a probe body in the form of a tube, a connector provided at one end of the probe body for connection with the measuring device body, and a sensing unit provided at the other end of the probe body through a sensor fixing part. In the sensing part, the sensing part provides a conductive probe including three vertices of an equilateral triangle drawn on the end face of the cylindrical fixing part and five sensors disposed inside the equilateral triangle.

Hereinafter, a five sensor conductive probe according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the conductive probe of the present invention is largely composed of a probe body 3, a connector 5, and a sensing unit 7 like a general flow measurement probe.

Here, first, the probe body 3 is bent in the letter “A” as shown as a wire guide in the form of a tube, and at one end for connection with a cable leading to the body of a measuring device such as a signal acquisition device (DAS). The connector 5 is attached, and the sensing part 7 is vertically connected to the other end bent at 90 degrees through the sensor fixing part 9 so that each of the sensors 11, 12, 13, 14, 15 The signal lines 10 are connected from the sensing unit 7 to the connector 5 via the probe body 3. In this case, as shown in the drawing, the horizontal portion of the body 3 close to the support point of the connector 5 may be made of a large diameter, and the vertical portion may be made of a small diameter to facilitate handling and stability. As the reference numeral 10, a high temperature enameled wire is used.

The sensor fixing part 9 connecting the sensing part 5 and the probe body 3 positioned at the tip of the vertical part of the probe 1 is fixed by inserting five sensors 11, 12, 13, 14, and 15. As shown in FIGS. 2A and 2B, holes 31 having a relatively large diameter, for example, 0.5 mm diameter, are penetrated in the longitudinal direction so that two sensors 11 and 15 can be inserted at the center at the same time. At the position where the vertex of the equilateral triangle comes around the hole 31, three holes 33 having a diameter of, for example, 0.25 mm having a diameter of about half of the hole 31 penetrate in the longitudinal direction. In addition, the locking jaw 35 is formed on the outer circumferential surface of the sensor fixing part 9 to be fitted to the end of the probe body 3.

As described above, the sensing unit 7 connected to the probe body 3 through the sensor fixing unit 9 includes five sensors 11, 12, 13, 14, and 15 as shown in FIGS. 1 and 3. Each sensor 11 to 15 is disposed inside a closed curve connecting three vertices and three vertices of an equilateral triangle having a side length of 1.0 mm drawn on the end face of the fixing part 9, for example. At this time, the flow factor measurement point is the end point of each sensor 11 to 15, and the interface area density can be obtained by measuring the electrical conductivity of the fluid near the end point of each sensor 11 to 15, and the configuration of the end point is the measurement result. Has a big impact on Therefore, in order to obtain highly accurate interfacial area data, all five sensors 11 to 15 must be distributed in a small area, so as shown, below the midpoint of the equilateral triangle and the midpoint of the equilateral triangle and the midpoint connecting the midpoint. One at each position. At this time, the sensor 11 positioned at the midpoint is, for example, 2.0 mm longer in length than the other sensors 12, 13, 14, and 15, as indicated by h in FIG. Therefore, as shown in FIG. 4, the lines connecting the tips of the sensors 11, 12, 13, 14 and 15 form a tetrahedron that is long in the longitudinal direction.

In order to arrange all the sensors 11 to 15 in such a small cross-sectional area, a special design of the sensor itself is required. In the present invention, the iron core 21 is used as it is instead of the tube into which the wire is inserted into the sensor. This is because the cross-sectional area of the iron core 21 is smaller than that of a commercially available tube, thereby reducing the total arrangement area of the sensor.

Here, each of the sensors 11 to 15 made of the iron core 21 has a diameter, for example, 0.18 mm, as long as a needle without an ear, and has a sharp tip as shown in FIG. 5. In addition, the iron core 21 is coated with, for example, a gold plated film 23 on the surface, and for example, the Teflon insulating film 25 is coated on the gold plated film 23 again.

Since the coated iron core 21 itself has an iron material, it is not only excellent in electrical conductivity but also advantageous in strength, thereby not only detecting abnormal flow information by measuring electrical conductivity, but also robustness in harsh flow conditions. It is advantageous to maintain. In addition, the sensors 11 to 15 are electrically insulated by coating the Teflon insulating film 25 on the entire outer circumferential surface except the end point in order to measure the conductivity of the fluid only at the end point.

At this time, however, the signal may be very weak because only a very small portion of the end points of the sensors 11 to 15 are electrically exposed in the flow. Therefore, in order to obtain a good signal, the iron plate 21 is coated with a gold plated film 23 having good electrical conductivity. Another reason for coating the gold dog film 23 as described above is that it is easy to use solder when connecting the rear ends of the sensors 11 to 15 to the signal line 10. If the signal line 10 is not connected by soldering, the diameter of the signal line connecting portion behind the sensors 11 to 15 becomes large, and the sensors 11 to 15 collide with each other, which is a major limitation in reducing the size of the sensor. do. The final thickness of each of the two layers of coated sensors 11-15 is, for example, 0.25 mm. As can be seen from 2a and 2b, the diameter of such a sensor is of sufficient length to place all five at the end of the sensor fixing part 9 with a radius of 1.0 mm into which the sensors 11 to 15 are inserted and fixed.

At this time, when manufacturing the sensing unit 7 to increase the positioning accuracy of the sensors 11 to 15 by using a separate prosthetic ball 41 as shown in Figs. 6a to 9, the fixing unit 9 and each sensor To combine (11 to 15).

Here, the prosthesis 41 is largely composed of a fixing part holding block 43, a primary auxiliary block 47, a secondary auxiliary block 51 and a housing block 55, the fixing part holding block 43 6A, 6B, and 9, the sensor 11 to 15 is welded to the fixing part 9 constituting the probe 1 sensing part 7 by a welding material such as epoxy. 11 to 15 serve to grip the fixing part 9 so that the fixing parts 9 can be inserted into the fixing part 9 and kept in place.

Therefore, the fixing hole 45 is formed in the center to hold the fixing portion 9, is divided into two along the center line so as to hold the fixing portion 9 from left and right. In addition, as shown in FIGS. 7A, 7B and 9, the primary auxiliary block 47 positioned below the fixing part holding block 43 may include sensors 11, 12, 13, 14, and 15 fitted to the fixing part 9. 5 through the primary through-hole 49 in the corresponding position so that the passage through, and as shown in Figures 8a and 8b, the secondary secondary block 51 installed below the primary secondary block 47 is The primary auxiliary block 47 has the same cross-sectional shape, and a secondary through hole 53 is formed in the center so that the front sensor 11 passing through the primary through hole 49 can pass therethrough. In addition, the housing block 55 which is fixed to the holding unit holding block 43 and the primary and secondary auxiliary blocks 47 and 51 without being moved around is fixed to the fixing unit through the assembly hole 57 opened in the center. The block 43 and the primary and secondary auxiliary blocks 47 and 51 are stacked in order from above.

Therefore, according to this prosthesis 41, since the lower part of the sensor fixing part 9 is inserted into and fixed to the fixing hole 45 of the fixing part holding block 43, the sensors 11 to the sensor fixing part 9 are fixed. 15) The insertion work can be precisely and easily carried out, and the sensors 11 to 15 are inserted into the primary through holes 49 and the sensors 11 are inserted into the secondary through holes 53 and fixed for high temperature. Producing the probe 1 is completed by bonding the upper part of the sensor fixing part 9 to the sensors 11 to 15 using an epoxy and performing a solidification process for one or more days.

Now, the flow factor measurement method of the ideal flow by the conductive probe according to the present invention configured as described above.

First, the signals of the flow factors are independently obtained by inserting the sensing unit 7 at the position to be measured of the target flow by the number of the sensors 11, 12, 13, 14, and 15 provided in the sensing unit 7. . That is, when an alternating current flows between each of the sensors 11, 12, 13, 14, 15 and the probe body 3, the fluid around the sensor end point acts as an electrical resistance on the circuit. The gas phase has a very high resistance, and the liquid phase has a small electrical resistance. Therefore, since the amount of current flowing varies depending on the type of fluid around the sensor end point, it is possible to determine the phase at the sensor end point by measuring the voltage across the output resistance of the circuit.

Next, it is determined whether each signal is a signal generated by the same bubble based on the signals obtained through the sensors 11 to 15 in step S10 (S20). For example, when the same bubble passes through the reference sensor and the rear sensors 11 and 12 sequentially, a bubble signal is generated from the sensors 11 and 12 at a time interval. This time difference is used to measure the velocity of bubbles. For velocity measurement, two bubble signals must be from the same bubble. Determination of whether the same bubble is made through a variety of methods, and a common method is to determine whether the two bubbles overlap each other from the point of time when the bubble signal is generated to determine the same bubble. This determination process is repeated for all rear sensors 12, 13, 14, and 15 from the reference sensor 11.

Next, the delay time of the four rear sensor 12 to 15 signals from the reference sensor 11 is measured so that the velocity component in the four directions of the interface, that is, from the sensor 11 at the point where the reference sensor 11 is located, is measured. The speed of four directions is measured in the direction of the sensors 12 to 15, wherein each speed component can be obtained from the distance / signal delay time between the end of the sensor 11 and the end of the sensor 12, for example. The sensors 11 and 13 (11 and 14) and 11 and 15 are repeated in the same manner to obtain a total of four speeds (S30).

Finally, the velocity component measured in the step (S30) is converted to the interface area density by the five-sensor probe measuring method, wherein the configuration of each sensor (11 to 15) of the five-sensor probe is as shown in FIG. Since the distance a0 between the tips of the rear sensors 12 to 15 affects the accuracy of the measurement. The spacing between each sensor tip should be small in order to reduce the frequency of bypass bubbles and to reduce errors due to the curved surface effect. In this example, a tip spacing of 1.0 mm was applied.

Therefore, since the probe 1 is composed of the front and rear sensors 11 and 15 at the center and the rear sensors 12, 13 and 14 at three symmetrical positions, the probe 1 is used at the interface of the interface. Vertical velocity components can be obtained, and bubble factors can be measured more effectively than conventional methods for bubbles bypassing one or more rear sensors. The direction vector component from the front sensor 11 to each rear sensor 12 to 15 can be induced into the geometry of the probe.

That is, the interfacial area data can be obtained using four velocity components and the direction vector. The method of obtaining the interfacial area is applied by dividing the shape of the interface passing through the sensors 11 to 15 into four categories. If the interface passes through all five sensors, bypasses one of the rear sensors 12, 13, 14, and bypasses two of the rear sensors 12, 13, 14, the center front and rear sensors 11, 15 ) Only passes in each case, and the interface area density is measured by applying an independent methodology to the interface corresponding to each group (S40).

As described above, according to the five-sensor conductive probe of the present invention, in measuring the area of the interface at an ideal flow rate, the area of the interface can be effectively measured even under the flow conditions in which small bubbles exist by keeping the cross-sectional area of the measurement part very small. Of course, other local anomalous flow factors such as bubble rate and bubble rate can be effectively measured.

In addition, according to the method of manufacturing the probe sensing unit of the present invention, since a predetermined sensor having a desired size can be reproduced with the same standard, mass production of the probe is possible, thereby maximizing probe production efficiency.

1 is a schematic representation of a five sensor conductive probe in accordance with the present invention.

Figure 2a is a plan view of the sensor fixture.

2B is a cross-sectional view taken along the line AA of FIG. 2A;

3 is a perspective view of a sensing unit of the probe shown in FIG. 1.

4 is a conceptual diagram illustrating a tetrahedron obtained by connecting the tip of the probe sensor shown in FIG.

5 is a longitudinal cross-sectional view of the sensor shown in FIG.

Figure 6a is a plan view of the holding grip block.

6B is a longitudinal cross-sectional view of FIG. 6A;

7A is a plan view of a primary auxiliary block.

FIG. 7B is a cross-sectional view taken along the line BB of FIG. 7A. FIG.

8A is a plan view of a secondary auxiliary block.

8B is a longitudinal cross-sectional view of FIG. 8A.

9 is an exploded perspective view of a prosthesis holding a sensor of a sensing unit of a probe;

Explanation of symbols on the main parts of the drawings

1: probe 3: probe body

5 connector 7 sensing unit

9 sensor fixing part 10 signal line

11: long rod sensor 12,13,14,15: single rod sensor

21: iron core 23: gold plated film

25: insulating film

Claims (6)

Probe body (3) in the form of a tube, a connector (5) provided at one end of the body (3) for connection with the measuring device body, the other end of the body (3) is provided through a sensor fixing portion (9) In the probe 1 composed of the sensing unit 7, The sensing unit 3 is characterized in that it comprises three vertices of an equilateral triangle drawn on the end surface of the cylindrical fixing part 7 and five sensors 11, 12, 13, 14, and 15 arranged inside the equilateral triangle. Conductive probe. According to claim 1, The sensors 11, 12, 13, 14, and 15 are positioned on the center line of the equilateral triangle while being in contact with the long rod sensor 11 arranged at the midpoint of the equilateral triangle, the three vertices of the equilateral triangle, and the long rod sensor 11. A conductive probe, characterized in that consisting of four single-sensor sensors (12, 13, 14, 15) arranged at each point. The method of claim 2, The length of one side of the equilateral triangle is 1.0 mm, and the length difference h between the long rod sensor 11 and the single rod sensors 12, 13, 14, and 15 is 2.0 mm. Accordingly, the sensors 11, 12, 13, 14, 15) a line connecting the tip of the conductive probe characterized in that the longitudinally long tetrahedron. According to claim 1, Each of the sensors 11, 12, 13, 14, and 15 has a long thin iron core 21 having a sharp tip, a gold plated film 23 coated on the surface of the iron core 21, and a gold plated film 23. A conductive probe comprising a coated Teflon insulating film (25). The method according to any one of claims 1 to 4, The sensing unit 7 has a fixing hole 45 is formed in the center to hold the fixing part 9 is fixed part holding block 43 is bisected along the centerline of the fixing hole 45, The fixing part holding block so that each of the sensors 11, 12, 13, 14, and 15 fitted to the fixing part 9 is inserted into each corresponding primary through hole 49 penetrating the same line. 43) the primary auxiliary block (47) to be installed below; A secondary installed under the primary auxiliary block 47 so that the sensor 11 passing through the primary through hole 49 is inserted into a corresponding secondary through hole 53 penetrating on the same line; Auxiliary block 51, and By means of a prosthesis (41) consisting of the housing block (55) to sandwich the fixing part holding block 43 and the primary and secondary auxiliary blocks (47, 51) in order from the top through the assembly hole (57) When the sensors 11, 12, 13, 14, 15 and the fixing part 9 are bonded by a welding material, the sensors 11, 12, 13, 14, 15 are to be held in place. Characterized in that the conductive probe. Insert the sensing unit 7 including the five sensors 11, 12, 13, 14, and 15 of the probe 1 at the position where the flow is to be measured, to independently separate signals as many as the numbers of the sensors 11 to 15. Obtaining step (S10), Determining whether each signal is a signal generated by the same bubble (S20) based on the signals obtained from the sensors 11 to 15 in the step S10, Measuring the delay time of the signals of the four rear sensors 12 to 15 from the reference sensor 11 to measure velocity components in four directions of the interface at the point where the reference sensor 11 is located (S30), and The flow measurement method using a conductive probe, characterized in that the step (S40) characterized in that for measuring the interface area density value of the flow around the sensor (11 to 15) using the velocity component measured in the step (S30).