TWI574019B - Waveguide Structures of Time Domain Reflectometry - Google Patents

Description

Time domain reflection waveguide structure

The present invention relates to a device for measuring the depth of an underwater object, and more particularly to a waveguide structure for measuring the depth of an underwater object by means of time domain reflection.

Time Domain Reflectometry (TDR) is a method of monitoring and probing using electromagnetic wave transmission. The electromagnetic wave transmission system uses a wave guide as a signal transmission and sensing element. The design of the waveguide is mainly to convert the environmental change parameters to be monitored into the transmission signal change (reflection signal) of the waveguide to know the environmental change parameters by the reflected signal. In actual implementation, the reflection signal generated by the electromagnetic wave in different environmental interfaces is measured, and then the electromagnetic wave velocity and the reflected signal are used to calculate the discontinuous position of the signal, thereby obtaining the environmental variation parameter.

However, since electromagnetic waves generate multiple reflections during the process of monitoring the transmission (such as entering the water from the air), the reflection signals of the environmental parameters to be tested are more difficult to distinguish. In addition, electromagnetic wave transmission is often susceptible to foreign matter interference and signal attenuation. More importantly, when electromagnetic waves are emitted from a high dielectric constant environment (such as water) to a low dielectric constant environment (such as soil, sludge, etc.), total reflection occurs, resulting in the inability to detect environmental parameters with low dielectric constant.

In view of the above, the inventors of the present invention have made great efforts to solve the above problems in view of the above-mentioned prior art, and have made great efforts to solve the above problems, which has become the object of improvement of the present inventors.

It is an object of the present invention to provide a time domain reflective waveguide structure that facilitates foreign matter interference to facilitate measurement and energy measurement of environmental parameters of different media.

In order to achieve the above object, the present invention provides a time domain reflective waveguide structure including a control module, a guided wave sensor, a protection kit and an insulator. The control module is configured to send the sensing signal and receive the reflected signal fed back by the sensing signal. The guided wave sensor is electrically connected to the control module, and includes a first probe connected to the control module, a curved probe connected to the first probe, and a second probe extending from the curved probe. The protection kit coaxially fits the first probe and exposes the curved probe, and the sensing signal passes through the first probe without interference, and is transmitted to the curved probe and the second probe to obtain a reflection signal, and the insulator package Covered outside the guided wave sensor and protection kit.

Another object of the present invention is to provide a time domain reflection waveguide structure which is provided with a reference probe which is exposed outside the insulator and is parallel to one side of the first probe, and the curve of the reflected signal Can be used as a benchmark to facilitate subsequent calculations.

Compared with the conventional servo structure, the time domain reflection waveguide structure of the present invention coaxially fits the protection kit outside part of the guided wave sensor, thereby preventing the sensing signal from passing through the protection kit. Disturbed by foreign objects to avoid attenuation of the sensing signal, so that the guided wave sensor has long-distance sensing capability; and when the sensing signal is transmitted from a high dielectric constant environment (such as water) to a low dielectric constant environment ( In the case of soil, sludge, etc., there is no total reflection, so that the guided wave sensor can smoothly transmit the sensing signal to the low dielectric constant environment, thereby smoothly generating the reflected signal to calculate the material level height; The present invention can additionally provide a reference probe exposed outside the insulator, and the curve of the reflected signal can be used as a comparison reference to facilitate subsequent calculations, thereby increasing the utility of the present invention.

1‧‧‧Time domain reflection waveguide structure

2‧‧‧First medium

3‧‧‧Second medium

10‧‧‧Control Module

11‧‧‧ coaxial cable

20‧‧‧ guided wave sensor

21‧‧‧First probe

22‧‧‧Bending probe

23‧‧‧Second probe

30‧‧‧protection kit

31‧‧‧Insulation tube

32‧‧‧Metal tube

320‧‧‧Perforation

40‧‧‧Insulator

41‧‧‧ Near end

42‧‧‧ distal

50‧‧‧ benchmark probe

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A is a cross-sectional view showing the structure of a time domain reflection waveguide structure of the present invention.

FIG. 1B is a schematic diagram showing the curve of the time domain reflection waveguide structure of the present invention without detecting the front reflection signal.

2A is a first schematic view of the structure of the time domain reflective waveguide of the present invention.

2B is a schematic diagram showing the reflection of the reflected signal of FIG. 2A.

3A is a second schematic view of the structure of the time domain reflective waveguide of the present invention.

Fig. 3B is a schematic diagram showing the reflection of the reflected signal of Fig. 3A.

Figure 4 is a second embodiment of the structure of the time domain reflective waveguide of the present invention.

The detailed description and technical content of the present invention are set forth in the accompanying drawings.

Please refer to FIG. 1A and FIG. 1B , which are respectively a cross-sectional view of the structure of the time domain reflection waveguide of the present invention and a schematic diagram of a curve of the undetected front reflection signal. As shown in FIG. 1A, the present invention provides a time domain reflective waveguide structure 1 including a control module 10, a guided wave sensor 20, a protection package 30 and an insulator 40. The control module 10 is electrically connected to the guided wave sensor 20, and the protective cover 30 is a part of the guided wave sensor 20, and the insulator 40 covers the guided wave sensor 20 and the protection Kit 30 is constructed to form the time domain reflected waveguide structure 1.

The control module 10 is configured to send a sensing signal and receive a reflected signal fed back by the sensing signal. In this embodiment, the sensing signal is an electromagnetic wave, and the reflected signal is the sensing signal. The value of the signal reflected back when the signal passes through the transmission interface. Preferably, the control module 10 further includes a coaxial cable 11 , and the guided wave sensor 20 is electrically connected to the control module 10 through the coaxial cable 11 .

The guided wave sensor 20 is electrically connected to the control module 10 . Moreover, the guided wave sensor 20 includes a first probe 21 connected to the control module 10, a curved probe 22 bent to connect the first probe 21, and a first extension extending from the curved probe 22 Two probes 23. In actual implementation, the guided wave sensor 20 can be formed by an integrally formed one-conductor steel rod. In this embodiment, the second probe 23 extends linearly from the end of the curved probe 22, and the second probe 23 is parallel to the first probe 21.

The protection kit 30 coaxially fits the first probe 21 and exposes the curved probe 22. In an embodiment of the present invention, the protection kit 30 includes an insulating tube 31 and a metal tube 32. In addition, the insulating tube 31 is sleeved with the first probe 21, and the metal tube 32 is sleeved thereon. The insulating tube 31 is outside. Preferably, the distance between the second probe 23 and the protection kit 30 is greater than 50 mm.

Preferably, the insulating tube 31 and the metal tube 32 have the same length; further, the metal tube 32 has a through hole 320 having a diameter smaller than the diameter of the insulating tube 31 and larger than the first probe 21 The diameter of the first probe 21 passes through the through hole 320 to connect the curved probe 22. Accordingly, the first probe 21 is threaded into the insulating tube 31, and the insulating tube 31 is plugged in the metal tube 32. The function of the protection kit 30 will be described in more detail later.

Since the protection kit 30 includes the metal tube 32 capable of shielding the signal interference, the sensing signal can pass through the protection kit 30 without being interfered by foreign objects, so as to avoid the attenuation of the sensing signal, so that the guided wave sensor 20 has Long stroke sensing capability. For example, when the guided wave sensor 20 is transferred from a high dielectric constant environment (such as water) to a low dielectric constant environment (such as soil, sludge, etc.), the first probe 21 is coaxially fitted with the protection kit. 30, so that the sensing signal does not cause total reflection between the two interfaces or other The interference enables the guided wave sensor 20 to smoothly transmit the sensing signal to the low dielectric constant environment, thereby smoothly generating the reflected signal to calculate the material level height.

Furthermore, the insulator 40 is wrapped around the waveguide sensor 20 and the protection package 30. In this embodiment, the two ends of the insulator 40 are a proximal end 41 and a distal end 42 respectively. The proximal end 41 and the distal end 42 are respectively closed ends to prevent external moisture or rain from infiltrating; The distal end 42 is spaced a distance from the end face of the protective sleeve 30, and the curved probe 22 is positioned between the end face of the protective sleeve 30 and the distal end 42. In actual implementation, the insulator 40 may be composed of engineering plastics such as polytetrafluoroethene (PTFE), polyether ether ketone (PEEK), or polyvinylidene fluoride (PVDF), but This is a limitation.

Preferably, the insulator 40 is a cylinder; in addition, the diameter of the insulator 40 becomes larger as the diameter of the waveguide sensor 20 increases. In addition, the diameter of the insulator 40 is proportional to the diameters of the first probe 21, the curved probe 22, and the second probe 23, when the first probe 21, the curved probe 22, and The larger the diameter of the second probe 23, the larger the diameter of the insulator 40, so that the guided wave sensor 20 has an appropriate impedance value. It should be noted that when the materials of the insulator 40 are different, the diameter of the insulator 40 is also different. In an embodiment of the invention, the impedance of the guided wave sensor 20 and the insulator 40 is about 50 ohms, which is not limited by the actual implementation.

Please refer to FIG. 1B , which is a schematic diagram showing a curve displayed by the reflected signal when the time domain reflective waveguide structure 1 is not measured. FIG. 1B is a graph showing the reflected signal of the time domain reflected waveguide structure 1 when the sensing signal passes through the air, wherein the point a is the reflected signal value transmitted by the sensing signal to point A in FIG. 1A.

2A and FIG. 2B are respectively a schematic diagram of the first use of the structure of the time domain reflection waveguide of the present invention and a schematic diagram of the reflected signals thereof. As shown in FIG. 2A, the time domain reflection waveguide The structure 1 is disposed in a first medium 2 (such as a liquid such as water) and a second medium 3 (such as an object such as sludge) for detecting the level of the first medium 2 and the second medium 3; The dielectric constant of the first medium 2 is greater than the second medium 3.

As shown in FIG. 2B, the reflected signal curve of the sensing signal of the time-domain reflective waveguide structure 1 passes through the first medium 2 and the second medium 3, wherein the point b is the sensing signal transmitted to the map. The reflected signal value of point B in 2B. That is, the present invention can know the level of the second medium 3 by the travel time calculation at point B in FIG. 2B. It should be noted that the method of calculating the level of the material through the travel time of the reflected signal is not the focus of the application of the present invention, and therefore will not be described in detail.

Please refer to FIG. 3A and FIG. 3B , which are respectively a second schematic diagram of the structure of the time domain reflection waveguide of the present invention and a waveform diagram thereof. As shown in FIG. 3A, the time domain reflection waveguide structure 1 is disposed in a first medium 2 (such as a liquid such as water) and a second medium 3 (such as an object such as sludge) for detecting the first medium. 2 and the material level height of the second medium 3, and the dielectric coefficient of the first medium 2 is greater than the second medium 3.

As shown in FIG. 3B , a curve of the reflected signal returned by the sensing signal of the time domain reflected waveguide structure 1 when the first medium 2 and the second medium 3 pass through, wherein the point c is a sensing signal. The reflected signal value transmitted to point C in Fig. 3B. That is, the present invention can know the level of the second medium 3 by the travel time calculation at point C in FIG. 3B.

Please refer to FIG. 4, which is a second embodiment of the structure of the time domain reflection waveguide of the present invention. This embodiment is substantially the same as the previous embodiment. The time domain reflective waveguide structure 1 includes a control module 10, a guided wave sensor 20, a protection package 30, and an insulator 40. The difference in this embodiment is that the time domain reflection waveguide structure 1 further includes a reference probe 50. The reference probe 50 is electrically connected to the control module 10, and The reference probe 50 is exposed outside the insulator 40 and parallel to one side of the first probe 21, and the sensing signal is selectively transmitted to the guided wave sensor 20 or the reference probe 50.

As shown in FIG. 4, when the sensing signal is transmitted to the reference probe 50, the measured reflected signal can be used to monitor the level of the first medium 2. Accordingly, after the sensing signal passes through the reference probe 50, the curve of the reflected signal can be used as a comparison reference to facilitate subsequent correlation calculation.

1‧‧‧Time domain reflection waveguide structure

10‧‧‧Control Module

11‧‧‧ coaxial cable

20‧‧‧ guided wave sensor

21‧‧‧First probe

22‧‧‧Bending probe

23‧‧‧Second probe

30‧‧‧protection kit

31‧‧‧Insulation tube

32‧‧‧Metal tube

320‧‧‧Perforation

40‧‧‧Insulator

41‧‧‧ Near end

42‧‧‧ distal

Claims (10)

A time domain reflective waveguide structure includes: a control module for transmitting a sensing signal and receiving a reflected signal fed back by the sensing signal; a guided wave sensor electrically connected to the control module The guided wave sensor includes a first probe connected to the control module, a curved probe connected to the first probe, and a second probe extending from the curved probe; a protection kit Coaxially fitting the first probe and exposing the curved probe, the sensing signal is transmitted through the first probe without interference, and transmitted to the curved probe and the second probe Obtaining the reflected signal; and an insulator completely covering the guided wave sensor and the protection kit. The time domain reflective waveguide structure of claim 1, wherein the control module further comprises a coaxial cable, and the guided wave sensor is electrically connected to the control module through the coaxial cable. The time domain reflective waveguide structure of claim 1, wherein the second probe extends linearly from an end of the curved probe, the second probe being parallel to the first probe. The time domain reflective waveguide structure of claim 3, wherein the distance between the second probe and the protection kit is greater than 50 mm. The time domain reflective waveguide structure of claim 1, wherein the guided wave sensor is formed by an integrally formed one conductor steel bar. The time domain reflection waveguide structure according to claim 1, wherein the protection kit comprises an insulation tube and a metal tube, the insulation tube sleeves the first probe, and the metal tube sleeve is sleeved on the insulation Outside the tube. The time-domain reflective waveguide structure according to claim 6, wherein the insulating tube has the same length as the metal tube, the metal tube has a bottom surface and a through hole formed in the bottom surface, the diameter of the through hole is smaller than the The diameter of the insulating tube is larger than the diameter of the first probe, and the first probe passes through the through hole. The time-domain reflective waveguide structure according to claim 1, wherein the two ends of the insulator are a proximal end and a distal end, and the distal end is kept at a distance from an end surface of the protection kit. The rod is positioned between the end face of the protective sleeve and the distal end. The time domain reflection waveguide structure according to claim 1, wherein the insulator is a cylinder, and the diameter of the insulator becomes larger as the diameters of the first probe, the curved probe and the second probe increase. . The time domain reflection waveguide structure of claim 1, further comprising a reference probe electrically connected to the control module, the reference probe being exposed outside the insulator and located in parallel The sensing signal is selectively transmitted to one side of the first probe to the guided wave sensor or the reference probe.