CN113108864A - Liquid level meter based on transmission and reflection characteristics of signal in variable impedance medium - Google Patents
Liquid level meter based on transmission and reflection characteristics of signal in variable impedance medium Download PDFInfo
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- CN113108864A CN113108864A CN202110347413.7A CN202110347413A CN113108864A CN 113108864 A CN113108864 A CN 113108864A CN 202110347413 A CN202110347413 A CN 202110347413A CN 113108864 A CN113108864 A CN 113108864A
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- 239000007788 liquid Substances 0.000 title claims abstract description 103
- 230000005540 biological transmission Effects 0.000 title claims abstract description 35
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- 230000005611 electricity Effects 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- -1 polytetrafluoroethylene Polymers 0.000 claims description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 4
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 4
- 238000002955 isolation Methods 0.000 abstract description 5
- 230000008859 change Effects 0.000 abstract description 4
- 238000000034 method Methods 0.000 abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 238000005259 measurement Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 230000004044 response Effects 0.000 description 3
- 230000003373 anti-fouling effect Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
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- 238000005260 corrosion Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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- 238000012827 research and development Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
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- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
The invention relates to the technical field of level instruments, in particular to a liquid level meter based on the transmission and reflection characteristics of signals in a variable impedance medium, which comprises a shell, wherein the top end of the shell is detachably connected with an end cover, a first liquid circulation hole and a second liquid circulation hole are respectively formed in the bottom end and the lower part of the side wall of the shell, a gas circulation hole is formed in the upper part of the side wall of the shell, an isolation rubber block is fixedly arranged on the inner wall of the shell, the shell is divided into an upper cavity and a lower cavity by the isolation rubber block, a circuit board is arranged in the upper cavity, a liquid induction line is arranged in the lower cavity, the top end of the liquid induction line penetrates through the isolation rubber block, and a signal generation module and. The liquid level measuring method and the liquid level measuring device utilize the principle that the transmission and reflection characteristics of signals can change when the impedance of a medium changes to measure the liquid level, and the liquid level measuring scheme is simple and easy to implement, high in measuring result precision, simple in liquid level meter assembly, convenient to maintain, convenient to use and good in universality.
Description
Technical Field
The invention relates to the technical field of level meters, in particular to a liquid level meter based on the transmission and reflection characteristics of signals in a variable impedance medium.
Background
The liquid level measurement has wide application in daily life and industrial production, such as water tanks and water towers, water tanks of solar water heaters, water tanks of electric water heaters, sewer pipe networks, chemical industry and other industrial production liquid reaction tanks.
The existing common liquid level measuring methods mainly include ultrasonic liquid level measurement, pressure transmission sensing liquid level, floater/floating ball liquid level measurement and capacitance transmission sensing liquid level. The ultrasonic liquid level measurement is high in cost and needs to be installed in a spacious space environment; the pressure sensing liquid level has higher requirements on water quality, sediment or scale deposits are easy to be misaligned or even damaged, and in addition, the pressure sensing liquid level has certain requirements on the sealing property because the pressure sensing liquid level is generally arranged at the bottom of a water tank; the contact carbon film of the float-type liquid level meter can be worn along with the service time, and is not suitable for conductive liquid such as water, and the mechanical switch of the float-type liquid level meter has certain requirements on the manufacturing process, and has a complex structure, and the number of measurement points is limited to a certain extent; the capacitance sensing liquid level has higher requirement on water quality and is greatly influenced by the blockage of silt and water scale.
In view of the above, the research and development of a liquid level meter which is simple in operation, high in precision and good in universality has great technical significance and economic significance.
Disclosure of Invention
The present invention is directed to a liquid level meter based on the transmission and reflection characteristics of signals in a variable impedance medium, so as to solve the problems mentioned in the background art.
In order to achieve the purpose, the invention provides the following technical scheme: a liquid level meter based on signal transmission and reflection characteristics in a variable impedance medium comprises a shell, wherein an end cover is detachably connected to the top end of the shell, a first liquid circulation hole and a second liquid circulation hole are respectively formed in the bottom end and the lower portion of the side wall of the shell, a gas circulation hole is formed in the upper portion of the side wall of the shell, an isolating rubber block is fixedly arranged on the inner wall of the shell and divides the shell into an upper cavity and a lower cavity, a circuit board detachably connected with the end cover is arranged in the upper cavity, a liquid induction line is arranged in the lower cavity, the top end of the liquid induction line penetrates through the isolating rubber block, a signal generating module and a signal acquisition module are fixedly arranged on the circuit board, the signal generating module is used for sending a step signal to the liquid induction line, and the signal acquisition module is used for acquiring a superposed signal on the liquid induction line, the superimposed signal represents a superposition of the step signal and a reflected signal of the step signal by an impedance discontinuity in the underlying cavity.
Optionally, a microcontroller is fixedly arranged on the circuit board, the output end of the microcontroller is electrically connected with the input end of the signal generation module, the input end of the microcontroller is electrically connected with the output end of the signal acquisition module, the input end of the microcontroller is electrically connected with a transmission line for transmitting current and signals, and the transmission line penetrates through the end cover.
Optionally, a threaded hole for accommodating the transmission line to pass through is formed in the end cover, a waterproof connector is fixedly arranged in the threaded hole, and the transmission line is fixedly sleeved on the waterproof connector.
Optionally, a support is fixedly arranged at one end of the shell, which is far away from the gas circulation hole, the support is in an inverted L shape, a bolt preformed hole is formed in the vertical end of the support, and the horizontal height of the bottom end of the support is lower than that of the bottom end of the shell.
Optionally, the surface of the liquid induction line is coated with a polytetrafluoroethylene anti-fouling coating.
Optionally, a rectangular groove is formed in the bottom end of the end cover, and the top end of the circuit board is embedded into the rectangular groove.
Compared with the prior art, the invention provides the liquid level meter based on the transmission and reflection characteristics of signals in the variable impedance medium, which has the following beneficial effects:
1. the liquid level measuring method and the liquid level measuring device utilize the principle that the transmission and reflection characteristics of signals can change when the impedance of a medium changes to measure the liquid level, and the liquid level measuring scheme is simple and easy to implement, high in measuring result precision, simple in liquid level meter assembly, convenient to maintain, convenient to use and good in universality;
2. according to the invention, the polytetrafluoroethylene anti-scaling coating is coated on the surface of the liquid induction line, so that impurities in liquid are prevented from being remained and adhered to the liquid induction line, the impedance on the liquid induction line is kept at a constant value, errors in secondary measurement are avoided, the requirement of the liquid level meter on water quality is not high, and the application range is wide.
Drawings
FIG. 1 is a schematic structural view of the present invention as a whole;
FIG. 2 is a waveform diagram of a step signal according to the present invention;
FIG. 3 is a waveform of a step signal after passing through a liquid level according to the present invention;
fig. 4 is a waveform diagram of a superimposed signal in the present invention.
In the figure: 1. a housing; 2. a first liquid flow aperture; 3. a gas flow aperture; 4. an end cap; 5. isolating rubber blocks; 6. a circuit board; 7. a liquid sensing line; 8. a signal generating module; 9. a signal acquisition module; 10. a microcontroller; 11. a transmission line; 12. a waterproof joint; 13. a support; 14. a second fluid flow aperture.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example (b): referring to fig. 1, the present invention provides a liquid level meter based on the transmission and reflection characteristics of signals in a variable impedance medium, which includes a housing 1, wherein the housing 1 is made of a corrosion-resistant metal material. First liquid circulation hole 2 and second liquid circulation hole 14 have been seted up respectively to the bottom and the lateral wall below of casing 1, place the level gauge in the container of splendid attire liquid, according to the linker principle, liquid gets into in casing 1 through first liquid circulation hole 2 and/or second liquid circulation hole 14, wherein second liquid circulation hole 14 can supply liquid to flow into in casing 1 from the lateral wall of casing 1 under casing 1 causes first liquid circulation hole 2 to be the condition of shutoff because of touching the end, the liquid level height in the container equals the liquid level height in casing 1. The upper part of the side wall of the shell 1 is provided with a gas circulation hole 3, when liquid enters the shell 1 from the first liquid circulation hole 2 and/or the second liquid circulation hole 14, air in the shell 1 overflows from the gas circulation hole 3, and bubbles are prevented from being generated.
The top end screw thread of casing 1 is connected with end cover 4, and 1 inner wall rubberizing of casing is connected with insulating rubber block 5, and two upper and lower cavitys are separated into with casing 1 to insulating rubber block 5, are located to be equipped with in the cavity of top and can dismantle the circuit board 6 of being connected with end cover 4, are located to be equipped with liquid induction line 7 in the cavity of below. Wherein, the bottom of end cover 4 has seted up the rectangular channel, and the top of circuit board 6 is embedded in the rectangular channel. The surface of liquid response line 7 coats and is coated with polytetrafluoroethylene anti fouling coating for prevent that impurity from remaining the adhesion on liquid response line 7 in the liquid, keep impedance on liquid response line 7 for the definite value, avoid the secondary to measure the error appearance. The top end of the liquid induction line 7 penetrates through the isolation rubber block 5, and the joint of the liquid induction line 7 and the isolation rubber block 5 is sealed by adopting rubber. The circuit board 6 is welded with a signal generating module 8 and a signal collecting module 9.
The signal generation module 8 is used for sending a step signal to the liquid induction line 7, the signal acquisition module 9 is used for acquiring a superposition signal on the liquid induction line 7, and the superposition signal represents superposition of the step signal and a reflection signal of an impedance discontinuity point in a cavity below the step signal to the step signal. The welding has microcontroller 10 on the circuit board 6, and microcontroller 10's output electricity is connected the input of signal generation module 8, and microcontroller 10's input electricity is connected the output of signal acquisition module 9, and microcontroller 10's input electricity is connected with the transmission line 11 that is used for transmission current and signal, and transmission line 11 runs through end cover 4. The end cover 4 is provided with a threaded hole for accommodating the transmission line 11 to pass through, the threaded hole is internally provided with a waterproof joint 12, the waterproof joint 12 is in threaded connection with the end cover 4, the waterproof joint 12 is fixedly sleeved with the transmission line 11, the transmission line 11 is used for connecting an upper computer, an instruction is sent to the microcontroller 10 through the upper computer, the real-time control signal generation module 8 is used for transmitting data acquired by the signal acquisition module 9 to the upper computer in real time.
The welding of the last one end of just keeping away from gas circulation hole 3 of casing 1 has support 13, and support 13 is the font of falling L, and the vertical of support 13 is served and has been seted up bolt preformed hole, and the level of support 13 bottom is less than the level of casing 1 bottom. The vertical end of the bracket 13 is mounted on the side wall of the container through a bolt, and the bottom end of the bracket 13 is abutted against the bottom wall of the container, so that the distance between the bottom end of the shell 1 and the bottom wall of the container is a fixed value.
The measurement principle is as follows: the invention utilizes the principle that the transmission and reflection characteristics of signals can change when the impedance of a medium changes to measure the liquid level. When there is no liquid in the container, i.e. the liquid sensing line 7 is not in contact with the measured medium, the impedance in the cavity below is continuous, the step signal propagates downwards along the liquid sensing line 7, and the waveform of the step signal refers to fig. 2. When liquid exists in the container and the liquid induction line 7 contacts a liquid medium to be detected, impedance change occurs in a cavity below the container, the peak value of the step signal changes correspondingly, a waveform diagram of the step signal passing through the liquid to be detected refers to fig. 3, meanwhile, a part of the step signal is reflected back, a part of the step signal continues to be transmitted downwards, the reflected signal is superposed on the generated step signal, the signal acquisition module 9 can acquire the superposed signal, and the waveform diagram of the superposed signal refers to fig. 4.
Because there is a certain time difference between the reflected signal and the step signal sent by the signal generation module 8, the edge of the superimposed signal is stepped, wherein the step distance reflects the time relation of signal propagation and reflection, and the step amplitude reflects the dielectric coefficient of the liquid to be measured, so that the impedance value of the impedance discontinuity point in the cavity below can be obtained according to the level amplitude of the step signal sent by the signal generation module 8 and the level amplitude of the superimposed signal.
The signal acquisition module 9 transmits the data of the superposed signals to the time domain reflectometer through the transmission line 11, a TDR curve can be displayed on a screen of the time domain reflectometer, the TDR curve and each point of the liquid induction line 7 have a one-to-one correspondence relationship, namely, the impedance value and the point distance of each point on the liquid induction line 7 can be read from the TDR curve, and if no liquid level exists, the point distances are equal; if the liquid level exists, the point distance changes at the liquid level, and the sum of the changed point distances is the liquid level height.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. A liquid level meter based on the transmission and reflection characteristics of signals in a variable impedance medium is characterized in that: the device comprises a shell (1), wherein an end cover (4) is detachably connected to the top end of the shell (1), a first liquid circulation hole (2) and a second liquid circulation hole (14) are respectively formed in the bottom end and the lower side of the side wall of the shell (1), a gas circulation hole (3) is formed in the upper side of the side wall of the shell (1), an isolating rubber block (5) is fixedly arranged on the inner wall of the shell (1), the shell (1) is divided into an upper cavity and a lower cavity by the isolating rubber block (5), a circuit board (6) detachably connected with the end cover (4) is arranged in the upper cavity, a liquid induction line (7) is arranged in the lower cavity, the top end of the liquid induction line (7) penetrates through the isolating rubber block (5), a signal generating module (8) and a signal collecting module (9) are fixedly arranged on the circuit board (6), and the signal generating module (8) is used for sending a step signal to the liquid induction line (7), the signal acquisition module (9) is used for acquiring a superposed signal on the liquid induction line (7), wherein the superposed signal represents superposition of the step signal and a reflection signal of the step signal to an impedance discontinuity point in a cavity below the step signal.
2. The liquid level gauge based on the transmission reflection characteristic of signals in a variable impedance medium according to claim 1, wherein: microcontroller (10) has set firmly on circuit board (6), the output electricity of microcontroller (10) is connected the input of signal generation module (8), the input electricity of microcontroller (10) is connected the output of signal acquisition module (9), the input electricity of microcontroller (10) is connected with transmission line (11) that are used for transmission current and signal, transmission line (11) run through end cover (4).
3. A gauge as claimed in claim 2, wherein the gauge is based on the transmission and reflection characteristics of a signal in a variable impedance medium: the end cover (4) is provided with a threaded hole for accommodating the transmission line (11) to pass through, a waterproof connector (12) is fixedly arranged in the threaded hole, and the transmission line (11) is fixedly sleeved on the waterproof connector (12).
4. The liquid level gauge based on the transmission reflection characteristic of signals in a variable impedance medium according to claim 1, wherein: the gas distribution device is characterized in that a support (13) is fixedly arranged at one end, far away from the gas circulation hole (3), of the shell (1), the support (13) is in an inverted L shape, a bolt preformed hole is formed in the vertical end of the support (13), and the horizontal height of the bottom end of the support (13) is lower than that of the bottom end of the shell (1).
5. The liquid level gauge based on the transmission reflection characteristic of signals in a variable impedance medium according to claim 1, wherein: the surface of the liquid induction line (7) is coated with a polytetrafluoroethylene anti-scaling coating.
6. The liquid level gauge based on the transmission reflection characteristic of signals in a variable impedance medium according to claim 1, wherein: the bottom end of the end cover (4) is provided with a rectangular groove, and the top end of the circuit board (6) is embedded into the rectangular groove.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110347413.7A CN113108864A (en) | 2021-03-31 | 2021-03-31 | Liquid level meter based on transmission and reflection characteristics of signal in variable impedance medium |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110347413.7A CN113108864A (en) | 2021-03-31 | 2021-03-31 | Liquid level meter based on transmission and reflection characteristics of signal in variable impedance medium |
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| CN113108864A true CN113108864A (en) | 2021-07-13 |
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| CN202110347413.7A Pending CN113108864A (en) | 2021-03-31 | 2021-03-31 | Liquid level meter based on transmission and reflection characteristics of signal in variable impedance medium |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3424002A (en) * | 1965-06-01 | 1969-01-28 | Marathon Oil Co | Apparatus for the determination of location of interfaces between different materials |
| JPH05322631A (en) * | 1992-05-19 | 1993-12-07 | Aisan Ind Co Ltd | Ultrasonic level detector |
| CN1232542A (en) * | 1996-10-07 | 1999-10-20 | 宾迪卡特公司 | Material interface level sensing |
| JP2011123012A (en) * | 2009-12-14 | 2011-06-23 | Ud Trucks Corp | Liquid level detector |
| CN103674159A (en) * | 2012-09-24 | 2014-03-26 | 罗斯蒙特储罐雷达股份公司 | Arrangement and method for testing a level gauge system |
| CN104374447A (en) * | 2014-11-21 | 2015-02-25 | 合肥工业大学 | Guided wave type radar level meter echo signal processing method based on first-order derivative with combination of reference curve |
| CN204649269U (en) * | 2015-06-01 | 2015-09-16 | 国电大渡河瀑布沟发电有限公司 | For the anti-saltus step device that power station top cover ultrasonic water level is measured |
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| CN112050898A (en) * | 2019-06-05 | 2020-12-08 | 深圳优威仪表技术有限公司 | Capacitance type oil level indicator |
-
2021
- 2021-03-31 CN CN202110347413.7A patent/CN113108864A/en active Pending
Patent Citations (9)
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|---|---|---|---|---|
| US3424002A (en) * | 1965-06-01 | 1969-01-28 | Marathon Oil Co | Apparatus for the determination of location of interfaces between different materials |
| JPH05322631A (en) * | 1992-05-19 | 1993-12-07 | Aisan Ind Co Ltd | Ultrasonic level detector |
| CN1232542A (en) * | 1996-10-07 | 1999-10-20 | 宾迪卡特公司 | Material interface level sensing |
| JP2011123012A (en) * | 2009-12-14 | 2011-06-23 | Ud Trucks Corp | Liquid level detector |
| CN103674159A (en) * | 2012-09-24 | 2014-03-26 | 罗斯蒙特储罐雷达股份公司 | Arrangement and method for testing a level gauge system |
| CN104374447A (en) * | 2014-11-21 | 2015-02-25 | 合肥工业大学 | Guided wave type radar level meter echo signal processing method based on first-order derivative with combination of reference curve |
| CN204649269U (en) * | 2015-06-01 | 2015-09-16 | 国电大渡河瀑布沟发电有限公司 | For the anti-saltus step device that power station top cover ultrasonic water level is measured |
| CN108139467A (en) * | 2015-09-11 | 2018-06-08 | 霍尼韦尔国际公司 | The device and method for detecting the fluent material of the end of the waveguide in guided wave radar system |
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Non-Patent Citations (1)
| Title |
|---|
| 孙灯亮: "《信号完整性测量》", vol. 1, 上海交通大学出版社, pages: 104 - 106 * |
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