CA2336925A1 - Moisture sensor for layers - Google Patents
Moisture sensor for layers Download PDFInfo
- Publication number
- CA2336925A1 CA2336925A1 CA002336925A CA2336925A CA2336925A1 CA 2336925 A1 CA2336925 A1 CA 2336925A1 CA 002336925 A CA002336925 A CA 002336925A CA 2336925 A CA2336925 A CA 2336925A CA 2336925 A1 CA2336925 A1 CA 2336925A1
- Authority
- CA
- Canada
- Prior art keywords
- moisture sensor
- layer
- conductors
- sensor according
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
- G01N22/04—Investigating moisture content
Abstract
The invention relates to a moisture sensor for layers, comprising at least two parallel electrical conductors, a feeder cable and a measuring device for detecting dielectricity coefficients.
The aim of the invention is to configure the sensor in such a way that the moisture can be measured from the outside. To this end both electrical conductors are surrounded by an insulating layer and on the side facing away from the layer are covered by a metallic shield layer so as to shield the half-space.
The aim of the invention is to configure the sensor in such a way that the moisture can be measured from the outside. To this end both electrical conductors are surrounded by an insulating layer and on the side facing away from the layer are covered by a metallic shield layer so as to shield the half-space.
Description
MOISTURE SENSOR FOR LAYERS
BACKGROUND OF THE INVENTION
The invention relates to a moisture sensor for layers, which moisture sensor comprises at least two parallel electri-cal conductors, a feeder cable and a measuring device for de-tecting dielectric coefficients.
For many applications, it is important to know the mois-ture content in thin material layers, which consist of a mix-ture of non-metallic solids material, water and air. A layer is considered to be thin if it can be rolled from a roll and layed out on an uneven surface, but is thicker than the largest l0 fragmented solid material element which is disposed in the mix-ture with water and air.
Particularly important examples for these objects are geo-synthetic clay or betonite mats. The collective denomination for these materials is geosynthetic (clay) liners. These mats, which typically have a thickness of about 4 mm to 30 mm, are preferably used as moisture and gas insulation in sealing ar-rangements of deposit bases and or/surfaces, for water retain-ing ponds, water ponds, dams, underwater installations and gen-erally in civil engineering construction sites. These mats 2o maintain their insulating capability as long as they do not dry out. In order to timely prevent their drying out, the moisture content of the mats alone must be continuously monitored with-out distortions by the construction materials above and below the mat. Generally, water is supplied to such a mat only at one side thereof. In this case, there may be a high gradient of the water content throughout the thickness of the mat with-out a loss of isolation quality. As a result, moisture content differences within the mat itself also need to be monitored.
The conference presentation "Measuring the In-situ Mois-ture Content of Geosynthetic Clay Liners (GCLS) Using Time Do main Reflectometry", Matthew A. Eberle and Kent P. von Mau beuge, in 1998 Sixth International Conference on Geosynthetics, 25 - 29 March 1998, Atlanta, USA represents adequately today's state of the art: The signal travel time along an electric conductor is measured which is inserted into the material to be monitored. The time determined in this way depends on the di-electric coefficient DK of the material to be monitored and the dielectric coefficient depends on the moisture content of the material.
The problems and disadvantages of the experiments de-scribed therein are as follows:
a) The electric measuring field extends beyond the mat layer thickness so that the materials below and above the mat have a falsifying influence on measuring result.
b) It is difficult to insert the measuring electrode of the probe exactly into the center of the mat.
c) The insertion probe can monitor only over relatively short non-representative length because the probe is rigid so that it cannot follow the mat-shape which is generally uneven.
d) It is known that air bubbles and air gaps between the probe and the material, whose formation is unavoidable when the probe is inserted, falsify the measuring value to a substantial degree which, furthermore, changes over time.
e) The measuring curve of the measuring impulse shown in the publication indicates that the determination of the pulse travel time, which is indicative of the moisture content, is not certain, since the attenuation along the measuring elec-trode is too high and because there is too much of an uncon-trollable mismatch of the impedances between the probe and the measuring apparatus.
These problems and disadvantages are the reason that stan-dard measuring probes for that purpose are commercially not yet available.
A weather report should include reports regarding the freezing conditions of the ground and the ice formation on ob jects close to the ground. The weather service therefore needs automatic icing sensors, which can distinguish between the con-ditions dry, moist, and frozen. At the present time, the Ger-man weather service determines these conditions by subjective observation. This method, however, should be replaced by ob-jective automatic measuring methods.
A feasibility study of intelligent sensors for measuring the ground condition by icing sensors, which was prepared by STS Systemtechnik Schwerin GmbH as ordered by the German weather service, Hamburg, 1997 describes a proposal wherein the propagation of sound (velocity and reflection) in a solid mate-rial, which is either dry or covered by a layer of water or ice, is measured. However, since the sound impedances of the three conditions have a relationship like 3.2 to 4 and to 1.5, a relatively complicated instrumentation is needed in order to empploy these distinctions. The apparatus is therefore rela-tively expensive.
The company Vaisala TMI Ltd, 349 Bristol Rd, Birmingham B57SW, UK offers a measuring system for road condition reports under the name IceCast Ice Prediction System. This system in-30, cludes a probe, which measures different parameters such as electric conductivity, polarization, DK, temperature of the street surface, depending on the condition. From these many data, a prediction of an ice formation danger is calculated.
BACKGROUND OF THE INVENTION
The invention relates to a moisture sensor for layers, which moisture sensor comprises at least two parallel electri-cal conductors, a feeder cable and a measuring device for de-tecting dielectric coefficients.
For many applications, it is important to know the mois-ture content in thin material layers, which consist of a mix-ture of non-metallic solids material, water and air. A layer is considered to be thin if it can be rolled from a roll and layed out on an uneven surface, but is thicker than the largest l0 fragmented solid material element which is disposed in the mix-ture with water and air.
Particularly important examples for these objects are geo-synthetic clay or betonite mats. The collective denomination for these materials is geosynthetic (clay) liners. These mats, which typically have a thickness of about 4 mm to 30 mm, are preferably used as moisture and gas insulation in sealing ar-rangements of deposit bases and or/surfaces, for water retain-ing ponds, water ponds, dams, underwater installations and gen-erally in civil engineering construction sites. These mats 2o maintain their insulating capability as long as they do not dry out. In order to timely prevent their drying out, the moisture content of the mats alone must be continuously monitored with-out distortions by the construction materials above and below the mat. Generally, water is supplied to such a mat only at one side thereof. In this case, there may be a high gradient of the water content throughout the thickness of the mat with-out a loss of isolation quality. As a result, moisture content differences within the mat itself also need to be monitored.
The conference presentation "Measuring the In-situ Mois-ture Content of Geosynthetic Clay Liners (GCLS) Using Time Do main Reflectometry", Matthew A. Eberle and Kent P. von Mau beuge, in 1998 Sixth International Conference on Geosynthetics, 25 - 29 March 1998, Atlanta, USA represents adequately today's state of the art: The signal travel time along an electric conductor is measured which is inserted into the material to be monitored. The time determined in this way depends on the di-electric coefficient DK of the material to be monitored and the dielectric coefficient depends on the moisture content of the material.
The problems and disadvantages of the experiments de-scribed therein are as follows:
a) The electric measuring field extends beyond the mat layer thickness so that the materials below and above the mat have a falsifying influence on measuring result.
b) It is difficult to insert the measuring electrode of the probe exactly into the center of the mat.
c) The insertion probe can monitor only over relatively short non-representative length because the probe is rigid so that it cannot follow the mat-shape which is generally uneven.
d) It is known that air bubbles and air gaps between the probe and the material, whose formation is unavoidable when the probe is inserted, falsify the measuring value to a substantial degree which, furthermore, changes over time.
e) The measuring curve of the measuring impulse shown in the publication indicates that the determination of the pulse travel time, which is indicative of the moisture content, is not certain, since the attenuation along the measuring elec-trode is too high and because there is too much of an uncon-trollable mismatch of the impedances between the probe and the measuring apparatus.
These problems and disadvantages are the reason that stan-dard measuring probes for that purpose are commercially not yet available.
A weather report should include reports regarding the freezing conditions of the ground and the ice formation on ob jects close to the ground. The weather service therefore needs automatic icing sensors, which can distinguish between the con-ditions dry, moist, and frozen. At the present time, the Ger-man weather service determines these conditions by subjective observation. This method, however, should be replaced by ob-jective automatic measuring methods.
A feasibility study of intelligent sensors for measuring the ground condition by icing sensors, which was prepared by STS Systemtechnik Schwerin GmbH as ordered by the German weather service, Hamburg, 1997 describes a proposal wherein the propagation of sound (velocity and reflection) in a solid mate-rial, which is either dry or covered by a layer of water or ice, is measured. However, since the sound impedances of the three conditions have a relationship like 3.2 to 4 and to 1.5, a relatively complicated instrumentation is needed in order to empploy these distinctions. The apparatus is therefore rela-tively expensive.
The company Vaisala TMI Ltd, 349 Bristol Rd, Birmingham B57SW, UK offers a measuring system for road condition reports under the name IceCast Ice Prediction System. This system in-30, cludes a probe, which measures different parameters such as electric conductivity, polarization, DK, temperature of the street surface, depending on the condition. From these many data, a prediction of an ice formation danger is calculated.
The system is complicated and very expensive. The apparatus is not suitable for measuring icing conditions near the ground.
The company Boschung Verkehrstechnik GmbH, Lutzowgasse 14 A-1140 Wien, Austria distributes a measuring system also for the prediction of road conditions. However, this system is also very complicated. Among others, it uses a procedure, wherein an isolated ground element is subjected to heating and cooling by Peltier elements. Also this system is unsuitable for monitoring ice formation near the ground.
l0 It is the object of the present invention to determine the actual condition of the ground surface and the icing of objects close to the ground and to provide a sensor by which the mois-ture can be determined from the outside.
SUMMARY OF THE INVENTION
In a moisture sensor for monitoring the moisture content of layers, at least two parallel electrical conductors con-nected to a measuring apparatus are disposed adj acent the lay-ers to be monitored. The conductors are surrounded by an insu-lating material and carry a metal shielding layer at their side remote from the layer whose dielectric coefficient is to be monitored for limiting the measurement field of the sensor.
The probe according to the invention has the following ad-vantages:
a) The electrodes (sensor, probe) are flexible. The probe can be disposed on an uneven surface of a material to be moni tored like a flexible flat cable.
b) The electrodes of the probe are provided with an elec-tric insulative coating and disposed at a constant distance from each other, whereby the electrical attenuation along the electrodes is kept relatively small. The small attenuation makes the construction of relatively long probes possible, which deliver representative monitoring results. The finite thickness of the insulation coating facilitates the provision of a metal shielding layer, whereby the electric field of the electrodes is shielded from the adjacent space without a direct short circuit and without a reduction of the measuring sensi-tivity. Then, the probe has a one-sided sensitivity. In this way, the probe does not need to be inserted into the material.
Only a small engagement pressure is needed to avoid the forma-tion of air gaps, which may falsify the measuring results.
c) By optimizing the distance between the electrodes and also the thickness of the insulation layer, the probe can be adjusted to the thickness of the material to be measured with l0 good impedance adaptation between the probe and the measuring apparatus. If necessary, or if there are doubts concerning the penetration depth of the measuring field, the one-sided measur ing field can be limited to the thickness of the material. In that case, the material is covered also on top with a metallic foil .
d) In order to reduce external electric disturbances, preferably a three conductor arrangement is utilized (See the report of Eberle and V. Meubeuge referred to above). If, in accordance with the invention, the center electrode of the three conductor arrangement is formed by the two adjacent con ductors of two electrode pairs arranged in parallel, another parameter is available, that is the distance between the elec trode pairs. With the selection of this distance, the imped ance of the probe arrangement can be advantageously selected for good adaptation.
The moisture sensor for layers becomes an icing detector in that a porous, water storing material layer is employed in place of the material layer to be measured. The porous mate-rial layer should consist of a non-metallic material, which has a low dielectric co-efficient DK and a very small volume pro-portion in a layer of about 5 - 10 mm thickness . Filter mats of polyester fibers with an area weight of 300 g/m2 and a thickness of 20 mm have been found to be suitable. The air-containing pores in this layer should be so small that, with the given surface tension of the water, raindrops can enter the pores but are retained within the layer. The DK of the layer in a dry state is only negligibly greater than 1, which is the DK of air. When exposed to rain, a water layer is formed within the porous material. The DK of the layer is then about 80, which is the DK of water. At temperatures below the freez-ing point, the water is converted to ice. As a result, the DK
of the layer will be about 3.15, which is the DK of ice. The water evaporation from the porous mat in comparison with the evaporation from an exposed water surface is only negligibly delayed.
The solution described herein utilized the differences of the DK values for the above-referred to states, (dry, moist, ice), which differ from one another like the number 1 to 80 and to 3.15. This increased dynamic permits a simplified instru-mentation when compared with the solutions described above. If two moisture sensors are used as icing detectors, one would be placed on the ground while the other would be suspended in the air close to the ground. In this way, a distinction can be made between icing on the ground and icing in the air close to the ground. Some embodiments of the invention will be described below in greater detail on the basis of the accompanying draw-ings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows schematically a particular embodiment of the sensor arrangements, Figs . 2a and 2b show another embodiment of the sensor ar-rangement, and Fig. 3 shows the sensor arrangement below the layer, which is to be monitored and which is covered by a metal layer.
DESCRIPTION OF EMBODIMENTS
Fig. 1 shows the sensor with the two electrodes 1 in the form of a two-conductor flat cable. An insulation layer 2 ex-tends around the conductors 1 (electrodes) and forms a distance structure between the conductors 1. A metal shield 3 shields the electric measuring field with respect to the space below.
With the selection of the distance dl, the layer thickness of the material 4 that can be measured can be determined.
Fig. 2a and Fig. 2b show an advantageous embodiment of the probe in a three-conductor arrangement including two sensors arranged in parallel. With the distance d2 between the two two-conductor cables, which form the three-conductor arrange-ment, the impedance adaptation of the sensors to the measuring apparatus can be advantageously controlled. Fig. 2b shows the circuit arrangement for the four conductors of such a triple electrode arrangement and the connection thereof to a measuring apparatus 6.
Fig. 3 shows the water permeable layer 4, which is to be measured, on top of the probe 1 with a metal shield 3 disposed below the probe and a metal shield 5 disposed on top of the layer 4 for delimiting the electrical field (measuring field).
By way of calibration measurements, the measured di electricity coefficients are assigned to various water contents of the layer.
If the sensor is used in connection with layers for the detection of icing conditions, the dielectric coefficients in different ranges are assigned to the conditions dry, moist and iced.
An embodiment of the sensor with two conductors separated by a web is about 60 mm wide and 700 mm long and about 1.5 mm thick. With a dl of 15 mm and a d2 of 20 mm water contents, based on weight, in the range of loo to 1500 are measured with an accuracy of about +5% even in a highly densified betonite.
The metal shielding layer is an adhesive tape provided with aluminum. The sensor is a three conductor-type sensor.
For use as an ice detector, a filter mat of polyester fi-bers with an area weight of 300g/m'' and a thickness of 20mm is used.
The company Boschung Verkehrstechnik GmbH, Lutzowgasse 14 A-1140 Wien, Austria distributes a measuring system also for the prediction of road conditions. However, this system is also very complicated. Among others, it uses a procedure, wherein an isolated ground element is subjected to heating and cooling by Peltier elements. Also this system is unsuitable for monitoring ice formation near the ground.
l0 It is the object of the present invention to determine the actual condition of the ground surface and the icing of objects close to the ground and to provide a sensor by which the mois-ture can be determined from the outside.
SUMMARY OF THE INVENTION
In a moisture sensor for monitoring the moisture content of layers, at least two parallel electrical conductors con-nected to a measuring apparatus are disposed adj acent the lay-ers to be monitored. The conductors are surrounded by an insu-lating material and carry a metal shielding layer at their side remote from the layer whose dielectric coefficient is to be monitored for limiting the measurement field of the sensor.
The probe according to the invention has the following ad-vantages:
a) The electrodes (sensor, probe) are flexible. The probe can be disposed on an uneven surface of a material to be moni tored like a flexible flat cable.
b) The electrodes of the probe are provided with an elec-tric insulative coating and disposed at a constant distance from each other, whereby the electrical attenuation along the electrodes is kept relatively small. The small attenuation makes the construction of relatively long probes possible, which deliver representative monitoring results. The finite thickness of the insulation coating facilitates the provision of a metal shielding layer, whereby the electric field of the electrodes is shielded from the adjacent space without a direct short circuit and without a reduction of the measuring sensi-tivity. Then, the probe has a one-sided sensitivity. In this way, the probe does not need to be inserted into the material.
Only a small engagement pressure is needed to avoid the forma-tion of air gaps, which may falsify the measuring results.
c) By optimizing the distance between the electrodes and also the thickness of the insulation layer, the probe can be adjusted to the thickness of the material to be measured with l0 good impedance adaptation between the probe and the measuring apparatus. If necessary, or if there are doubts concerning the penetration depth of the measuring field, the one-sided measur ing field can be limited to the thickness of the material. In that case, the material is covered also on top with a metallic foil .
d) In order to reduce external electric disturbances, preferably a three conductor arrangement is utilized (See the report of Eberle and V. Meubeuge referred to above). If, in accordance with the invention, the center electrode of the three conductor arrangement is formed by the two adjacent con ductors of two electrode pairs arranged in parallel, another parameter is available, that is the distance between the elec trode pairs. With the selection of this distance, the imped ance of the probe arrangement can be advantageously selected for good adaptation.
The moisture sensor for layers becomes an icing detector in that a porous, water storing material layer is employed in place of the material layer to be measured. The porous mate-rial layer should consist of a non-metallic material, which has a low dielectric co-efficient DK and a very small volume pro-portion in a layer of about 5 - 10 mm thickness . Filter mats of polyester fibers with an area weight of 300 g/m2 and a thickness of 20 mm have been found to be suitable. The air-containing pores in this layer should be so small that, with the given surface tension of the water, raindrops can enter the pores but are retained within the layer. The DK of the layer in a dry state is only negligibly greater than 1, which is the DK of air. When exposed to rain, a water layer is formed within the porous material. The DK of the layer is then about 80, which is the DK of water. At temperatures below the freez-ing point, the water is converted to ice. As a result, the DK
of the layer will be about 3.15, which is the DK of ice. The water evaporation from the porous mat in comparison with the evaporation from an exposed water surface is only negligibly delayed.
The solution described herein utilized the differences of the DK values for the above-referred to states, (dry, moist, ice), which differ from one another like the number 1 to 80 and to 3.15. This increased dynamic permits a simplified instru-mentation when compared with the solutions described above. If two moisture sensors are used as icing detectors, one would be placed on the ground while the other would be suspended in the air close to the ground. In this way, a distinction can be made between icing on the ground and icing in the air close to the ground. Some embodiments of the invention will be described below in greater detail on the basis of the accompanying draw-ings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows schematically a particular embodiment of the sensor arrangements, Figs . 2a and 2b show another embodiment of the sensor ar-rangement, and Fig. 3 shows the sensor arrangement below the layer, which is to be monitored and which is covered by a metal layer.
DESCRIPTION OF EMBODIMENTS
Fig. 1 shows the sensor with the two electrodes 1 in the form of a two-conductor flat cable. An insulation layer 2 ex-tends around the conductors 1 (electrodes) and forms a distance structure between the conductors 1. A metal shield 3 shields the electric measuring field with respect to the space below.
With the selection of the distance dl, the layer thickness of the material 4 that can be measured can be determined.
Fig. 2a and Fig. 2b show an advantageous embodiment of the probe in a three-conductor arrangement including two sensors arranged in parallel. With the distance d2 between the two two-conductor cables, which form the three-conductor arrange-ment, the impedance adaptation of the sensors to the measuring apparatus can be advantageously controlled. Fig. 2b shows the circuit arrangement for the four conductors of such a triple electrode arrangement and the connection thereof to a measuring apparatus 6.
Fig. 3 shows the water permeable layer 4, which is to be measured, on top of the probe 1 with a metal shield 3 disposed below the probe and a metal shield 5 disposed on top of the layer 4 for delimiting the electrical field (measuring field).
By way of calibration measurements, the measured di electricity coefficients are assigned to various water contents of the layer.
If the sensor is used in connection with layers for the detection of icing conditions, the dielectric coefficients in different ranges are assigned to the conditions dry, moist and iced.
An embodiment of the sensor with two conductors separated by a web is about 60 mm wide and 700 mm long and about 1.5 mm thick. With a dl of 15 mm and a d2 of 20 mm water contents, based on weight, in the range of loo to 1500 are measured with an accuracy of about +5% even in a highly densified betonite.
The metal shielding layer is an adhesive tape provided with aluminum. The sensor is a three conductor-type sensor.
For use as an ice detector, a filter mat of polyester fi-bers with an area weight of 300g/m'' and a thickness of 20mm is used.
For the electrical connection between the sensor and the measuring unit 6, a 20m long shielded cable can be used. The measuring unit 6 determines the DK values.
Claims (8)
1. A moisture sensor for layers, said moisture sensor in-cluding a conductor arrangement with two parallel electrical conductors connected to a measuring apparatus for determining dielectric coefficients, a cable including two spaced conduc-tors disposed between said two parallel conductors and con-nected with said two parallel conductors in a three-conductor circuit, the space between the conductors of said cable being selected for the adjustment of the impedance of said conductor arrangement, said electrical conductors being surrounded by an insulating material layer and carrying at one side, which is remote from the layer whose dielectric coefficient is to be measured, a metal shielding layer for limiting the measurement field of the moisture sensor.
2. A moisture sensor according to claim 1, wherein said conductors with said insulating layer arid said metal shielding are flexible.
3. A moisture sensor according to claim 1, wherein said conductors have a measuring field and they are arranged at a distance from each other, which is so selected, that the meas-uring depth of the measuring field is comparable to the thick-ness of the layer whose moisture content is to be determined.
4. A moisture sensor according to claim 1, wherein said conductors with the insulating layer and the metal shielding have a wave resistance which during measurement is adapted to the characteristic resistance of the measuring apparatus.
5. A moisture sensor according to claim 1, wherein a water permeable metal layer is disposed on top of the layer whose di-electric coefficient is to be monitored.
6. A moisture sensor according to claim 1, wherein said layer to be monitored consists of a porous water-retaining ma-terial.
7. A moisture sensor according to claim 1, wherein said moisture sensor is disposed adjacent a betonite layer for de-termining the water content thereof.
8. A moisture sensor according to claim 6, wherein said moisture sensor is disposed adjacent the ground for determining ice formation on the ground and on objects close to the ground.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19833331.5 | 1998-07-24 | ||
| DE19833331A DE19833331C2 (en) | 1998-07-24 | 1998-07-24 | Moisture sensor for layers |
| PCT/EP1999/003704 WO2000006998A1 (en) | 1998-07-24 | 1999-05-28 | Moisture sensor for layers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2336925A1 true CA2336925A1 (en) | 2000-02-10 |
Family
ID=7875164
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002336925A Abandoned CA2336925A1 (en) | 1998-07-24 | 1999-05-28 | Moisture sensor for layers |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US6507200B2 (en) |
| EP (1) | EP1102979B1 (en) |
| AU (1) | AU755818B2 (en) |
| CA (1) | CA2336925A1 (en) |
| DE (2) | DE19833331C2 (en) |
| WO (1) | WO2000006998A1 (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9054094B2 (en) | 1997-04-08 | 2015-06-09 | X2Y Attenuators, Llc | Energy conditioning circuit arrangement for integrated circuit |
| US7110235B2 (en) * | 1997-04-08 | 2006-09-19 | Xzy Altenuators, Llc | Arrangement for energy conditioning |
| US7336468B2 (en) | 1997-04-08 | 2008-02-26 | X2Y Attenuators, Llc | Arrangement for energy conditioning |
| US7301748B2 (en) | 1997-04-08 | 2007-11-27 | Anthony Anthony A | Universal energy conditioning interposer with circuit architecture |
| US7321485B2 (en) | 1997-04-08 | 2008-01-22 | X2Y Attenuators, Llc | Arrangement for energy conditioning |
| DE10150320A1 (en) * | 2001-06-13 | 2002-12-19 | Consens Gmbh | Precipitation detection method has an array of two moisture sensors that are used with an external temperature sensor in such a way that both fluid and solid precipitation can be detected |
| DE10150078A1 (en) * | 2001-06-14 | 2002-12-19 | Consens Gmbh | Precipitation sensor device for motor vehicle windscreen has a combination of temperature sensors, heaters and coolers that enables the reliable detection of both solid and liquid precipitation independently of surface dirt |
| AU2003245692A1 (en) * | 2002-06-24 | 2004-01-23 | Arichell Technologies, Inc. | Automated water delivery systems with feedback control |
| DE10245411B3 (en) * | 2002-09-28 | 2004-06-24 | Forschungszentrum Karlsruhe Gmbh | Moisture sensor for determining moisture from leakages in reservoir, clarifying tanks and swimming pools comprises measuring line sections, screened by-pass lines, a switch, and control lines for controlling the switch |
| US7225024B2 (en) * | 2003-09-30 | 2007-05-29 | Cardiac Pacemakers, Inc. | Sensors having protective eluting coating and method therefor |
| KR20060120683A (en) | 2003-12-22 | 2006-11-27 | 엑스2와이 어테뉴에이터스, 엘.엘.씨 | Internally shielded energy conditioner |
| US20050225335A1 (en) * | 2004-04-13 | 2005-10-13 | Filipkowski Leonard R | Moisture detector |
| US7817397B2 (en) | 2005-03-01 | 2010-10-19 | X2Y Attenuators, Llc | Energy conditioner with tied through electrodes |
| US7630188B2 (en) | 2005-03-01 | 2009-12-08 | X2Y Attenuators, Llc | Conditioner with coplanar conductors |
| CN101395683A (en) * | 2006-03-07 | 2009-03-25 | X2Y衰减器有限公司 | Energy conditioner structures |
| US8309024B2 (en) * | 2008-04-23 | 2012-11-13 | Enerize Corporation | Methods and systems for non-destructive determination of fluorination of carbon powders |
| US9909987B1 (en) | 2014-07-30 | 2018-03-06 | Transcend Engineering and Technology, LLC | Systems, methods, and software for determining spatially variable distributions of the dielectric properties of a material |
| US9970969B1 (en) | 2014-08-26 | 2018-05-15 | Transcend Engineering and Technology, LLC | Systems, methods, and software for determining spatially variable distributions of the dielectric properties of a heterogeneous material |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3824460A (en) * | 1973-04-02 | 1974-07-16 | R Gustafson | Leakage sensor |
| US3873927A (en) * | 1973-11-05 | 1975-03-25 | Surface Systems | System for detecting wet and icy surface conditions |
| US3965416A (en) * | 1974-05-28 | 1976-06-22 | Tylan Corporation | Dielectric-constant measuring apparatus |
| US4749731A (en) * | 1986-04-14 | 1988-06-07 | The Celotex Corporation | Coating for roof surfaces |
| JPH01285847A (en) * | 1988-05-13 | 1989-11-16 | Junkosha Co Ltd | Fluid detection sensor |
| DE3920787A1 (en) * | 1989-06-24 | 1991-01-10 | Kernforschungsz Karlsruhe | METHOD AND DEVICE FOR MEASURING THE VOLUME OF WATER IN MINERAL AND / OR ORGANIC MIXTURES |
| DE4213070A1 (en) * | 1992-04-21 | 1993-10-28 | Ingbuero Rinne Und Partner | Twin spaced apart conductor system for capacitance or resistance monitoring of land fill leakage - has sites which have been sealed against random losses of leachate |
| DE4334649C2 (en) * | 1993-04-29 | 1995-02-23 | Imko Intelligente Micromodule | Probe for material moisture sensor |
| US5648724A (en) * | 1996-02-08 | 1997-07-15 | U.S. Army Corps Of Engineers As Represented By The Secretary Of The Army | Metallic time-domain reflectometry roof moisture sensor |
-
1998
- 1998-07-24 DE DE19833331A patent/DE19833331C2/en not_active Expired - Fee Related
-
1999
- 1999-05-28 WO PCT/EP1999/003704 patent/WO2000006998A1/en active IP Right Grant
- 1999-05-28 CA CA002336925A patent/CA2336925A1/en not_active Abandoned
- 1999-05-28 AU AU45021/99A patent/AU755818B2/en not_active Ceased
- 1999-05-28 EP EP99927786A patent/EP1102979B1/en not_active Expired - Lifetime
- 1999-05-28 DE DE1999510850 patent/DE59910850D1/en not_active Expired - Lifetime
-
2001
- 2001-01-05 US US09/754,584 patent/US6507200B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| AU755818B2 (en) | 2002-12-19 |
| WO2000006998A1 (en) | 2000-02-10 |
| EP1102979A1 (en) | 2001-05-30 |
| DE19833331C2 (en) | 2001-02-15 |
| DE19833331A1 (en) | 2000-02-10 |
| DE59910850D1 (en) | 2004-11-18 |
| EP1102979B1 (en) | 2004-10-13 |
| US20010002105A1 (en) | 2001-05-31 |
| AU4502199A (en) | 2000-02-21 |
| US6507200B2 (en) | 2003-01-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6507200B2 (en) | Moisture sensor for layers | |
| CA2671083C (en) | Systems and methods for detecting anomalies on internal surfaces of hollow elongate structures using time domain or frequency domain reflectometry | |
| US8947102B1 (en) | Soil water and conductivity sensing system | |
| US20090212789A1 (en) | Modified tdr method and apparatus for suspended solid concentration measurement | |
| US20090273352A1 (en) | Sensor apparatus and system for time domain reflectometry | |
| CN110514959A (en) | A kind of cable fault FDR localization method and system considering cable attenuation characteristic | |
| RU2287883C1 (en) | Method for ice detection on power transmission line conductors | |
| Shang et al. | A complex permittivity measurement system for undisturbed/compacted soils | |
| RU2476868C2 (en) | Water detector | |
| JP2001231119A (en) | Insulator contamination detector and insulator contamination detecting system | |
| Stähli et al. | A new in situ sensor for large-scale snow-cover monitoring | |
| CA2310020A1 (en) | Method of determining the volumetric proportion of liquid water and the density of snow and a device for carrying out the method | |
| Mojid et al. | The use of insulated time-domain reflectometry sensors to measure water content in highly saline soils | |
| JP2960549B2 (en) | Humidity sensor for spreading layers | |
| Lin et al. | Monitoring of icing behavior based on signals from a capacitance sensor | |
| CN213875905U (en) | Capacitive sensor for cable insulation detection | |
| US5942904A (en) | Moisture sensor for large area layers | |
| WO2011081526A1 (en) | Method and system for detecting faults in laminated structures | |
| RU2780947C1 (en) | Method for controlling the accumulation of fatigue damage in wires of an overhead power transmission line | |
| Ilinykh et al. | Assessment of technical condition of underwater transitions of main pipelines in real | |
| EP0943080B1 (en) | A moisture sensing membrane and a method of detecting moisture | |
| O’Connor et al. | Real time monitoring of infrastructure using tdr technology: Principles | |
| Huebner et al. | Near-subsurface moisture sensing | |
| FR3112613A1 (en) | INSTRUMENT AND METHOD FOR ANALYZING A COMPLEX MEDIUM TO DETERMINE ITS PHYSICO-CHEMICAL PROPERTIES | |
| CN110554071A (en) | System and method for detecting hydrophobicity of contaminated insulator based on phase angle difference method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |