WO1994009354A1 - Systeme de controle de la corrosion - Google Patents

Systeme de controle de la corrosion Download PDF

Info

Publication number
WO1994009354A1
WO1994009354A1 PCT/US1993/009617 US9309617W WO9409354A1 WO 1994009354 A1 WO1994009354 A1 WO 1994009354A1 US 9309617 W US9309617 W US 9309617W WO 9409354 A1 WO9409354 A1 WO 9409354A1
Authority
WO
WIPO (PCT)
Prior art keywords
corrosion
elements
current
voltages
sensors
Prior art date
Application number
PCT/US1993/009617
Other languages
English (en)
Inventor
Mark T. Byrne
Kenneth L. Kimes
John T. Stropki
Original Assignee
Battelle Memorial Institute
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Battelle Memorial Institute filed Critical Battelle Memorial Institute
Priority to AU53250/94A priority Critical patent/AU5325094A/en
Publication of WO1994009354A1 publication Critical patent/WO1994009354A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/20—Investigating the presence of flaws
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body

Definitions

  • This invention relates to corrosion monitoring and in particular to a method and apparatus for the continuous, automatic, and remote monitoring of potentially corrosive environments in difficult-to-reach places.
  • a method and apparatus has now been devised wherein corrosion sensors may be positioned in difficult- to-access and confined spaces having potentially corrosive environments to provide periodic automated testing, reporting, and/or recording to positions remote to such spaces.
  • the instant corrosion monitor system consists of sensors, preamplifiers, a controller, and a battery pack.
  • the system can support a number of sensors, each with dedicated preamplifiers, to monitor many sites in a given installation.
  • the preamplifiers, controller, and battery- pack may be packaged as a single instrumentation unit.
  • Sensors can be attached to the instrumentation via cables (advantageously up to 100 feet (30.5 meters) long, or longer) .
  • Each sensor may combine a thermistor and two corrosion-sensing elements.
  • the sensor elements are connected as a resistive half-bridge, or its equivalent, with a reference and an exposed element.
  • the instru ⁇ mentation system passes a forward current through the sensor and measures the voltage differential between the exposed and reference elements in order to determine corrosion activity. Measurement of sensor temperature allows the raw corrosion activity data to be temperature- compensated.
  • the reference and exposed sensor elements may be fabricated with the same material as the structure of interest, thus an environment that causes corrosion in the structure under observation would also cause corrosion in the exposed sensor element.
  • the reference element is sealed to prevent corrosion from changing its resistance.
  • Sensor corrosion manifests itself as a change in the resistivity of the sensor element.
  • Typical corrosion rates in aircraft produce resistance changes on the order of hundreds of microohms or less per year.
  • a fundamental design problem in the development of a corrosion monitor system for such applications is the detection of small changes in sensor resistance over time and at the same time satisfy package size and low power consumption constraints.
  • the expected corrosion changes result in differential voltage levels at the preamplifier input on the order of tens of microvolts.
  • the present system is automatic in the sense that no operator is needed. It can be installed with the sensors and left in place to record resistance changes on a periodic basis over an extended period of time. In the demonstration system, corrosion measurements are made once a day. The measurement rate can be changed to meet the requirements of a specific application. When the instrument is not taking data, it may be made to shut down to extend battery life. Periodically, the data stored by the corrosion monitoring system can be transferred to an external computer for post-processing and interpretation.
  • a particularly advantageous feature that may be incorporated into the present system is a preamplifier subsystem. To meet the criteria of the present need
  • small, low-noise, low-power preamplifiers were devised to convert the very small sensor output to a usable signal.
  • the corrosion monitor system of the present invention has been found to be particularly useful to aid in the evaluation of anti-corrosion surface treatments.
  • two corrosion sensors are placed together in the area to be evaluated.
  • One of the sensors contains a bare test conductor.
  • the other sensor is treated with the same anti-corrosive coating that is used on the parts or surfaces to be protected from the corrosive environment, such as the section of the aircraft in which it would be used.
  • the bare sensor then yields data that shows how the local surfaces to be tested, such as the aircraft surfaces, would react if they were untreated.
  • the coated sensor demonstrates the surface treatment's relative capability in preventing premature corrosion. Together, the two sensors help to determine the overall effective ⁇ ness of surface coatings.
  • Fig. 1 is a plan view of a sample test probe used in the method and apparatus of the present invention
  • Fig. 2 is a schematic circuit block diagram of a DC monitoring system embodying the features of the present invention, with the elements of the preamp shown to the left of the dashed line and the elements of the controller shown to the right of the dashed line;
  • Fig. 3 is a schematic circuit block diagram of the controller board of an AC monitoring system embodying the features of the present invention
  • Fig. 4 is a graph showing corrosion test results for thin-film aluminum sensors using the process and apparatus of the present invention, where sensor output in microohm/cm2 is presented on the left vertical axis (Y) and the exposure time in hours is presented on the lower horizontal axis (X) ;
  • Fig. 5 is a graph showing corrosion test results for thin-film steel sensors, where sensor output in microohm/cm2 is presented on the left vertical axis (Y) and the exposure time in hours is presented on the lower horizontal axis (X) ; and
  • Fig. 6 is a graph showing corrosion test results for thin-film Type 7075-T6 aluminum sensors, where weight change in micrograms/cm2 is presented on the left vertical axis (Y) and the exposure time in hours is presented on the lower horizontal axis (X) .
  • Corrosion monitor sensors of the type employed in conjunction with the method and apparatus of the present invention are well known in the art.
  • a sensor that may be employed in conjunction with the present invention is described in U.S. Patent No. 2,834,858 to E. Schaschl.
  • the sensing material and its physical parameters depend on the local surfaces to be evaluated and the corrosiveness of their environment.
  • the sensor operates on the principal that corrosion of a metallic conductor will cause a corresponding increase in the cross-sectional electrical resistance of that conductor. This increase in resistance is due to actual material loss during the corrosion of the metallic surface. This material reduction is most noticeable in the appearance of small holes on the surface known as pitting. As conductive material is removed by corrosion, electron flow is limited due to reduced electrical path.
  • the electrical resistance of the test conductor is read as a voltage across the conductor by passing a constant (i.e., direct) current through it.
  • the test probe of Fig. 1 comprises a coupon 100 made of the test material.
  • This material is the same as that of the structural materials to be monitored. Such material is generally an aluminum alloy where the monitoring is for aircraft.
  • Coupon 100 is divided into two halves 102 and 104 that are separated by a spacing channel 106.
  • Coupon 100 is enveloped in a protective plastic envelope or coating 108 that covers and protects from corrosion all of the surfaces of coupon 100 (back and front) except one surface of half 102 that is exposed by a window 110 provided in envelope 108.
  • Half 104 of coupon 100 is covered on all surfaces by the protective envelope or coating 108.
  • Leads 112 and 114 are connected to coupon half 104 and extend from the front surface of envelope 108 (the back surface of envelope 108 extends beyond the front surface) .
  • Leads 116 and 118 are similarly attached to coupon half 102.
  • a single lead 120 extends from the bottom of the spacing channel 106 between halves 102 and 104 to extend beyond the protective envelope 108.
  • coupon half 102 is the test conductor and half 104 is the reference conductor.
  • Lead 116 may be attached to power source 109 of the system of Fig. 2; lead 118 may be connected to contact 111; lead 112 may go to ground; lead 114 may be connected to contact 115; and lead 120 may be attached to contact 121.
  • Fig. 2 of the drawings shows the major system electronic components and circuits. Both the controller and dual preamp circuits are covered by this diagram. The principal circuits and signals are numbered, and the circuit board jumpers are lettered for reference in the circuit descriptions. Note that the alphanumeric designations used on this block diagram are to serve as references only and are not derived from actual part numbers or jumper letter identifiers. The jumper designations called out in the initialization and download procedures described later in this text are actual circuit jumper designators and differ from the references shown in the block diagram and listed in the circuit descriptions.
  • Each sensing probe contains two conductors, test and reference, which are monitored by the system. The reference conductor is sealed to protect it from the corrosive environment.
  • the test conductor is exposed to the environment for open air testing or the application of any representative coatings to be evaluated. Since the percentage change in the resistance of the test conductor is extremely small, a comparison method is used which measures the impedance of the test conductor with respect to the reference conductor. The system monitors relative changes in the electrical resistance of the test conductor by comparing the voltage across it to that of the reference conductor. This comparison method enables the system to detect very small incremental changes (micro- ohms) in the resistance of the test conductor. This method also adds some built-in compensation for the effects of ambient temperature on the resistance of the material as the reference and test conductors are equally affected. The probes also include built-in thermistors for local temperature indication. The probes are connected to the main system compartment via seven conductor plus ground shielded 24AWG cables. Further details concerning the test probe circuit interface are contained in the preamp circuit description.
  • any electronic or electricity dependant device will vary to at least some degree in accordance to the temperature to which it is subjected during operation. Such effect may be negligible or may be of some conse ⁇ quence where comparative measurements are such as in the present instance.
  • One solution to the problem is to simply take temperature measurements in the vicinity of the operating devices with conventional instruments such as a thermometer and calculate appropriate compensations in the output of the device since the temperature effect on such components is known or may be easily developed. This is easily accomplished in conjunction with the operation of the systems of the present invention because its reduction to practice has been essentially accomplished with conventional devices such as described below, and the temperature effect on such devices is known.
  • thermistors which automatically or which may be made to effect such temperature compensations.
  • Such devices may vary in the manner by which they function but generally function in accordance with the description found in the publication OMEGA Temperature Handbook. 1991, pp Z24 & 25 which is incorporated herein and made a part of this specification.
  • Thermistors or the application of temperature compensation are well know in the art and are not claimed as a part of the present invention since viable results may be achieved with either the application of a commercially available thermistor device or conventional temperature measuring instruments. Such technology is described herein to assure the best mode in practicing the present invention has been made available to those of ordinary skill in the art.
  • the dual preamp board (see Fig. 2) provides the circuitry to interface two test probes to the controller board. This circuitry converts very small sample sensor resistance changes into analog voltages and interfaces these signals to the controller board analog to digital converter (A/D 211) .
  • A/D 211 controller board analog to digital converter
  • 100mA of current 259 is supplied to each of the probes by a constant current source circuit 215.
  • the resultant voltage across the test conductor 225, 226 is input to an instrumentation amplifier 201.
  • the voltage across the reference conductor 226, 227 is also input to an instrumentation amplifier 202.
  • These first stage amplifiers amplify the conductor voltages by approximately a factor of 1000.
  • the resultant output signals 228, 231 are processed through dual cascaded non-inverting low pass filters 209, 210 which also amplify the signals by a factor of about 2.5.
  • the filter outputs 246, 247 are input to a final amplifier stage 211 which yields the difference between the two signals amplified by a factor of 20.
  • the preamp circuit provides an overall gain of 50,000 to the voltage difference between the test and reference conductors.
  • the final output is then routed to a 12 bit A/D converter 207 on the controller circuit board.
  • Each of the preamp boards contains two preamp circuits and as many as four preamp boards may be used per system under current configuration. This creates the potential for as many as eight channels of information to be input to the A/D converter 207. Slight circuit modifications would allow even more input channels if necessary.
  • Jumper F represents one of eight jumpers per dual preamp board that directs the analog output signal to its corresponding input channel 236 into the A/D converter 207.
  • Each probe also provides a temperature input 261 from a built-in thermistor (not shown) .
  • the eight temperature inputs are routed to the controller circuit board in the same manner as that described above.
  • Jumper o represents one of the eight jumpers per preamp board that directs the analog temperature signal to its corresponding input channel 245 into the microcontroller's onboard A/D converter.
  • the electrical resistance of the thermistor varies with temperature.
  • the thermistor is connected into a two-resistor (10K ⁇ to +5V and 10K ⁇ to ground) voltage divider in parallel to the bottom resistor.
  • the varying thermistor resistance causes the parallel leg resistance ( ⁇ The rmis to r & 10K ⁇ ) to vary along with the leg voltage. This analog voltage level is read and stored by the microcontroller.
  • Power 249 is provided to the dual preamp board by a high-side driver circuit 213 on the controller board.
  • This power input is connected to the preamp voltage converter 212, voltage regulator 214, constant current source 215, and current enable circuit 222.
  • the preamp voltage converter 212 converts the 12 volts supplied by the high-side drive circuit 213 to a -5 volt supply 229 for the instrumentation amplifiers 201 and 202, the filter circuits 209 and 210, and the instrumentation amplifier 211.
  • the preamp voltage regulator 214 converts the 12 volt input from the controller board to a +5 volt supply 230 for the dual preamp board (i.e., amplifiers 201 and
  • the preamp current circuit 215 converts the 12 volt input into a 100mA constant current source 259 which is run through the test probes. This source is directly controlled by a signal 251 from the enable circuit 222 which is driven by the controller board.
  • Jumper P represents one of four jumpers per preamp board that directs the current control output signal 252 from the controller board.
  • the current supplied to the test probe represents the majority of the power consumed by the corrosion monitor system. Since the data from the A/D converter is read sequentially, each preamp board is enabled and disabled consecutively. In this manner no two boards are energized simultaneously, maximum battery current is minimized, and battery life is extended.
  • Jumpers A and B are used to simulate the connection of an external test probe for each channel by shorting the inputs to the first stage amplifiers. These jumpers are used during board testing and tuning which is further described later.
  • the two channels on each preamp board connect to the controller board via a 24 pin in-line connector.
  • Jumpers F, O, and P represent three jumper sets per channel of each preamp board. These jumper sets are used to determine which of the eight potential channels of data and control each preamp circuit represents.
  • the controller board contains the main control circuitry for the corrosion monitor system.
  • the controller board enables and disables the power and constant current source for each of the preamp boards and extracts data from them in a sequential manner at regular time intervals.
  • the controller board also provides all user interface, which includes system setup, data retrieval through an RS-232 serial port 219, and system reset control via switch S 1.
  • Each line of corrosion probe output data forms one of eight analog inputs 236 to the 12 bit A/D converter 207.
  • the resultant digital output signal 248 is clocked into the microcontroller 216 (hereafter also referred to as the microprocessor) .
  • Jumpers C and D are used to set the input range 235 of the A/D converter. Jumper C sets the analog input range at 0 to +2.5 volts. Jumper D sets the input range at -2.5 to +2.5 volts. The jumper is typically placed in position C since corrosion causes a positive output as the voltage across the test conductor is increased with respect to that of the reference conductor.
  • the controller board circuitry includes a precision reference 208 which provides +2.5 volts 244 to the controller 216, A/D converter 207, and voltage inverter circuit 203. This reference also has a built-in temperature sensing capability.
  • Jumper E represents one of eight jumper positions which will allow the user to connect this temperature output into any one of the controller's A/D converter input lines in place of the corresponding input 245 from the preamp board. This allows monitoring of the temperature inside the system enclosure during operation. Since the test probes are typically placed in pairs to help evaluate coating materials, it is only necessary to use one temperature output for each pair of probes. If one of the four extra temperature input jumpers is disconnected, the controller board temperature input can be jumped into the vacant input channel.
  • a decoder/latch 221 is used by the micro ⁇ controller 216 to manage several on-board functions. Five signal lines 257 from the microprocessor 216 are used to control the decoder. The current enable output represents four signals 252 that are routed to the preamp boards to turn on the current source for the test probes consecutively. Another decoder output 250 controls the high-side driver 213 which supplies power to all of the preamp boards. A third control output 258 from the decoder 221 shuts down the negative voltage converter 223 and one of the voltage regulators 224. The final decoder output 253 connects to jumper K, which allows the microprocessor to control the RS-232 port.
  • the controller board contains several micro ⁇ processor support circuits which include the real-time clock 204, controller reset/watchdog 205, RS-232 circuit 218, and memory 217.
  • the real-time clock 204 is set to run at 32.768 KHz and provides full clock and calendar features. Multiple signals 237 between the real-time clock and controller provide time and date information to wake up the controller at a preset interval.
  • the reset/watchdog circuit 205 provides a reset output 239 to the microprocessor and real time clock 204 for power-up, power-down, and brownout conditions. This circuit also provides a power fail warning input 239 to the controller 216 as it monitors the battery input voltage level 241.
  • the power fail circuit uses a resistive divider with the watchdog's 205 interval 1.3 volt threshold to indicate a low battery status when the battery voltage drops below 6.5 volts.
  • the RS-232 circuit 218 transmits/receives serial data to/from the microprocessor 216 through two data lines
  • the controller board contains a right angle D-9 serial connector (serial port 219) for interface to an external computer.
  • the RS-232 circuit includes two sets of jumpers for changeable control. Jumpers M and N allow choice of +5 volt supplies to the circuit. Position M connects the circuit to the output 233 of the voltage regulator 206 which is always on. Jumper position N connects to the regulator 224 which can be shut off by the controller 216. The jumper is typically placed in position N so that the RS-232 circuit can be disabled to eliminate quiescent current consumption. Jumpers K and L connect to the enable input of the RS-232 circuit. Position K is the normal operating position as it allows control 253 of the serial port by the microprocessor. Position L connects +5 volts to enable the RS-232 circuit. This position is used during the data retrieval process described later.
  • the corrosion monitor system program software is stored on a 32K byte EEPROM memory circuit 217 which connects to the controller through multiple ports 242. This memory stores the program software and all of the data that is captured by the system.
  • the microprocessor's on-board memory is used only to store the software which writes data to the external EEPROM 217. No data or other program information is stored in the controller memory.
  • the microprocessor 216 is connected to three pairs of jumpers to control various modes of operation for the system. Two of these pairs (jumpers G, H, I, J) control the operating mode inputs 238 and 240 of the controller with respect to external memory recognition.
  • Both jumpers are placed in the +5 volt position (G and I) which places the controller in the expanded multiplexed mode and indicates the use of an external memory circuit.
  • the third pair of jumpers (R and S) control the input 256 to one data line of the microprocessor's parallel port. These jumpers determine the system data acquisition interval.
  • Position S sets the normal operating or 24-hour mode which causes the system to awake and take data once per day.
  • Position R enables the debug mode and causes the system to take data approximately every two minutes.
  • the debug mode is typically used during initial setup to verify system functionality and probe output data.
  • the battery ground line 260 is connected to the digital ground.
  • Jumper Q connects the analog and digital grounds together and is in place during normal operation.
  • the battery input 241 connects to the voltage converter circuit 223, two voltage regulators 224 and 206, the reset/watchdog circuit 205, and a high-side driver 213.
  • the voltage converter circuit 223 provides a -5 volt supply 243 for the voltage inverter 203 and 12 bit A/D 207.
  • the first voltage regulator 206 is always enabled and provides +5 volts 233 to the real-time clock 204, EEPROM 217, microprocessor 216, and decoder/latch 221, as well as jumpers G, I, L, M, and R.
  • This five-volt supply is also connected to the reset/watchdog circuit 205 via normally closed momentary switch SWl, which provides system reset when temporarily opened.
  • a second +5 volt regulator 224 is identical to the first except that it can be shut off by the controller. This regulator supplies power 232 to the +2.5V reference 208, 12 bit A/D, voltage inverter circuit 203, and jumper position N.
  • the voltage inverter circuit 203 provides -2.5 volts 234 for the A/D input range setting as described earlier.
  • the amount of current flow required for effecting the method of the present invention depends, of course, on the specific requirements and parameters of the system being tested.
  • the primary requirement is that it be a constant DC current.
  • Such current must be of low amperage to conserve the battery utilized since for many applica ⁇ tions such as aircraft a satisfactory non-battery electrical source is not available.
  • amperage will not exceed about 0.5 amperes.
  • Particular success has been achieved with 100mA.
  • the voltages applied to all of the various components and subcircuits, such as the regulators and inverters, may also, of course, vary.
  • Amplification of the sensor elements' voltage for measurement is of particular importance for the low current densities (preferably no greater than about 0.5 amperes) of the present system. As shown above, particular success has been achieved when employing 100mA current with amplifications of 50,000. However, optimum amplification will vary in accordance with the exact current input. Generally, it will not be possible to detect voltage increases that show significant corrosion of an element where such total amplification is less than about 20,000. Where such amplifications exceed about 60,000 it is not possible to effectively determine the voltage increases due to static interference which accompanies such low current density amplifications and which may not be adequately filtered from the system.
  • the above described corrosion monitor is programmed to measure and record sensor signals at predetermined intervals.
  • Procedures for downloading corrosion data from the corrosion monitor have been demonstrated using a special communications program within the Smarterm 240 software package.
  • This program allows all "raw" voltage signals emitted from the corrosion sensors and stored within the data acquisition system to be transferred onto a magnetic diskette via a laptom computer. Once transferred, a second routine in the program allows the user to initialize the corrosion monitor to begin data collection procedures.
  • All sensor (voltage) data is input into Lotus 1-2-3 and subsequently stored on magnetic diskettes. The data is then automatically normalized with respect to the resolution or sensitivity of the system, and converted into real-time corrosion measurements. A time-dependent statistical analysis is performed on the measurements recorded by the individual sensors. The software package used to perform these analyses is Table Curve. Once analyzed, a comparative evaluation is performed on all measurements to determine differences and/or similarities in the trends recorded for sensors installed in identical areas on aircraft.
  • In situ corrosion rates are calculated for all sensors by measuring the relative change in response signals (increase in signal strength denotes corrosion) noted for the individual sensors as a function of exposure time. Numerical constants related to the composition and thickness of the sensor's "test element" as well as yearly conversion factors are included in these calculations. Post-analysis presentation of all sensor data is set-up and displayed using Lotus PrintGraph software. The corrosion monitor system operation is fully automated and should not require service, once set up, until battery pack replacement (4-6 months) . Before the system is put into place, probes are paired with preamp boards for board tuning. This tuning process sets the data starting point at zero as there should be no corro ⁇ sion on the test probes at this time.
  • the tuning process includes adjusting the amplifier offsets such that the output of each stage and the final data output are set to zero. After all of the preamp boards are tuned with respect to certain probes, the system is put into place and the probes are connected to their respective board channels. The system is then initialized through the following procedure:
  • the corrosion monitor system will acquire data once per day (for up to 200 days) after initialization and will store the data in EEPROM memory.
  • the microprocessor remains in an inactive or "sleep" state when no data is being acquired.
  • the controller is "awakened” by an interrupt to set the program in motion.
  • the controller then applies power to the preamp boards. Power to the preamp boards is left on for 15 minutes before any data is collected to ensure that the supply voltages have reached equilibrium.
  • the 100mA current source is enabled on the first preamp board. The current is passed through the two test probes and a data point is received, converted, and stored in memory.
  • Temperature data is also collected and stored at this time. Once this data is collected, the 100mA current source for the first board is disabled. The current source for the second board is then enabled, and the process is repeated. After corrosion and temperature data has been collected and stored for all of the test probes (up to eight) , the microprocessor returns to its "sleep" mode until the following day.
  • the corrosion monitor data should be retrieved at the time that the battery pack is replaced.
  • the procedure for downloading the data is as follows:
  • the corrosion monitoring system as represented by the components of the drawing consists of, and functions in accordance with, well known electrical and electronic principles.
  • the function of the various components and their replacement with equivalent sub circuits are well within the skill of those of ordinary competence in the technology.
  • the following list of commercially available components are those that have been used to demonstrate the invention:
  • the dual preamp board provides the circuitry to detect and isolate the very small differen ⁇ tial signal due to sample sensor resistance changes from the larger common mode signal.
  • the output of the preamp board is an analog voltage which interfaces to the controller board A/D.
  • the previous information describes a direct current (DC) version of the preamp and interface circuit in which a lOOmA DC current is passed through the probe sensors.
  • An alternating current (AC) dual preamp circuit (See Fig. 3) can also be used, passing a single frequency AC signal through the corrosion sensors.
  • a timer circuit 302 generates a fixed frequency, fixed amplitude AC voltage signal 311 which is input to a constant RMS current op-amp circuit 301.
  • the constant RMS current circuit will provide a fixed amplitude AC current (preferably less than 0.5 amp.) excitation signal 322 to the probe sensors, regardless of changing loads created by various cable lengths.
  • the resultant AC voltage across the test conductor 315, 316 is amplified through a differential amplifier circuit 306.
  • the AC voltage across the reference element 316, 317 is also amplified by circuit 307.
  • the amplified AC test and reference signals 318, 319 are then compared through an additional differential amplifier 308.
  • phase-locked loop circuit 309 is an AC voltage which represents the difference in electrical resistance between the test conductor and the reference conductor. This signal 320 appears at the same frequency as the timing signal 311 frequency, differing in amplitude and/or phase.
  • the phase-locked loop circuit 309 will then lock onto only signals within a small bandwidth of this desired frequency, thereby rejecting external noise and DC bias components.
  • the output 321 of the phase-locked loop circuit 309 is a DC voltage which is proportional to the amplitude of the AC input signal 320 into the PLL. Proper amplification of this analog voltage
  • an interface amplifier 310 provides a DC analog voltage for the controller board 12 bit A/D, indicating any difference in electrical resistance between the test sensor and reference sensor of the corrosion probe.
  • the output 321 as amplified by amplifier 310 is a direct current indication of any difference in the electrical resistance between the corrosion probes, it is equivalent to the direct current indication from the DC dual preamp circuit of Fig. 2 emitted from the final amplifier 211 (Fig. 2) and provided to A/D converter 207 of the controller board. Accordingly output 321 as amplified by amplifier 310 is provided to such an A/D converter of a corresponding controller board to that described for the embodiment of Fig. 2.
  • power 249 is provided to the dual preamp board by a high-side driver circuit 213 on the controller board.
  • This power input is connected to the preamp voltage converter and voltage regulator.
  • the preamp voltage converter 305 converts the 12 volts supplied by the high- side drive circuit to a -5 volt supply 314 for the amplifiers, constant current, and phase-locked loop circuits.
  • the preamp voltage regulator 304 converts the 12 volt input from the controller board to a +5 volt supply 312 for the dual preamp board.
  • a current enable circuit 303 provides an output signal 313 which turns on the AC current supplied to the probe sensors.
  • Jumper P represents one of four jumpers per preamp board that directs the current control output signal 252 from the controller board. Jumpers O and F also function the same on the AC dual preamp board as on the DC board. Jumper O connects the thermistor circuit output 323 to one of eight temperature input channels on the controller board. Jumper F connects the corrosion data signal to its corresponding A/D input on the controller board.
  • Each electrical resistance-type sensor consists of a sensing element and a reference element. Real-time monitoring of the voltage differential between the two elements, which varies in response to corrosion or a reduction in the cross-sectional area of the sensing element, is used to determine the corrosiveness of the area being monitored.
  • Such thin films in the order of one to two mil thickness or less can be achieved on many supporting materials such as glass by known vapor deposition techniques such as sputtering.
  • Sensors must be fabricated from thin-films of steel and aluminum to optimize CDS performance in areas that are not extremely corrosive.
  • the recommended materials and film thicknesses for aircraft application are Type 1100-0 aluminum alloy (0.0006in. and/or 0.0012 inch) and AISI 1020 carbon steel (0.003 inch or thinner).
  • AISI Type 1100-0 aluminum electrical resistance (ER) sensors were evaluated for three weeks in each of three corrosion environments.
  • the approximate size of these sensors was 1.5 inches by 1.5 inches.
  • the nominal thicknesses of the elements (sensing and reference) were 0.0012 inch for one sensor and 0.0006 inch for the second sensor.
  • Controlled ion assisted vapor deposition (IAVD) techniques were used to deposit both a 3000 A thick layer of copper and the above specified thicknesses of aluminum onto a non- conductive 4.0-inch by 4.0-inch by 0.025-inch-thick ceramic substrate.
  • the copper was deposited onto one side of the entire sensor, except in the areas where the aluminum alloy was deposited.
  • a photoresist coating was applied over the aluminum sensor patterns. This coating served to protect the aluminum patterns while the copper/aluminum deposit was removed with an etching solution.
  • the resultant patterns remaining on the surface of the ceramic substrate material included multiple sensors, each containing a reference element and sensing element, a temperature compensating element, and five separate electrical connection pads (i.e., conforming to the sensors of Fig. 1) .
  • the procedures for tuning or "zeroing" the corrosion monitor preamplifier boards includes connecting the appropriate corrosion sensors to each board and setting the instrumentation amplifier offsets to zero for each channel. This procedure sets the offset channel output to zero when the current sources are off.
  • the initial readings with current applied are typically very small when the channels for each sensor are properly tuned. This initial value indicates the difference between the voltage measured across the reference and sensing elements of the sensor. With 100 mA of constant current flowing through the sensing elements, this value actually indicates the relative resistance between the reference and sensing elements. If thicker elements are used (8 mil Al, etc.), the initial values range within 100 and 200 mV of the tuned offset setting.
  • the gain on the preamplifier boards was set to approximately 50,000, meaning that the voltage at the output was approximately 50,000 times the difference between the voltage measured across the sensing and reference elements.
  • the resistance seen across the sensor elements is directly proportional to the inverse of the cross-sectional area.
  • the cross- sectional area is directly proportional to the thickness of the aluminum deposited on the ceramic substrate. Therefore, a tenfold reduction in the thickness of the aluminum sensors causes the sensor resistance to be multiplied by a factor of 10.
  • the sensing element of sensor Bl has experienced a 541 ⁇ increase in resistance due to corrosion.
  • the initial raw sensor data must be examined. This provides the zero current offset (listed as error on raw data summary) and the data for calculations.
  • the data starting value is determined by subtracting the zero current offset data from the actual initial data.
  • this particular sensor's output data begins at -2990 and will limit or "rail out” at 697.
  • Test Environment No. 1 Cyclic Temperature/Humidity These tests were performed in an automated Bristol® environmental chamber that was calibrated to alternate cycles of high humidity-hot air and low humidity-hot air. A single 24-hour cycle consisted of 8 hours at 90 percent relative humidity (RH) and 80° F (27° C) .
  • the CDS unit was programmed to record sensor measurements during both of these intervals throughout the duration of the test. Condensate collection on the surfaces of the test materials was minimized by mounting all sensors and coupons vertically within the cabinet. In addition the individual sensors were isolated from one another to eliminate the possibility of corrosion product cross-contamination. Test Environment No.
  • the FMG corrosion test environment was incorporated into this program because it realistically simulates the kinetics and degradation mechanisms found on metal components after long-term (10 to 15 years) exposures to a polluted industrial indoor environment, similar to an electrical control room.
  • Studies have confirmed that the low levels of gaseous pollutants within the Class III multicomponent FMG laboratory environment are aggressive enough to corrode aluminum and steel materials. The levels of damage varied as a function of sensor materials and exposure time, but it was concluded that the onset and development of corrosion were visually verified on exposed metal within 3 weeks of exposure.
  • the exposure of steel and aluminum sensors to this environment provided information which was used to quantify the low-level sensitivity and measurement accuracy of the different sensors and/or the CDS package.
  • the concentrations of the various gaseous pollutants (Cl 2 , H 2 S and N0 2 ) as well as the temperature and relative humidity (RH) levels that were maintained within the environmental chamber throughout the duration of the test exposure are documented in Table 1 below.
  • the CDS unit was programmed to record and store a single sensor measurement each day through out the scheduled exposure period.
  • Test Environment No. 3 Salt Fog/Dry-Air This accelerated corrosion test procedure was selected because it simulates the cyclic effects of wetting and drying the surfaces of materials operating in a coastal or marine environment.
  • the thermal cycling portion of the test is representative of the temperature changes which may occur in the areas on an aircraft that have a frequent exchange of air.
  • concentration of chloride ions in the laboratory test was selected on the basis that it represents a "worst case" scenario of the corrosive conditions that could exist on an aircraft stationed and/or operating in a corrosive marine environment.
  • the higher concentration limits were also required to corrode the test specimen within the short 500-hour exposure period that was used for accelerated laboratory testing.
  • the 24-hour test cycle that was maintained throughout the 3-week test period consisted of an 8-hour exposure to a salt fog that was heated to a temperature of approximately 80° F (27° C) .
  • the fog was automatically turned off and the chamber was heated with fan-forced, hot, dry air to a temperature of 100° F (38° C) for 16 hours.
  • This cycle was selected because it simulates a 2- to 3-year exposure to a warm marine environment.
  • the CDS was programmed to record sensor measurements during both of these intervals to determine the effects of temperature, time-of-wetness, and chlorides on the measurement sensitivity of various sensors. CDS data were compared with the visual examinations that were performed throughout the scheduled test period.
  • 7075-T6 aluminum fabricate from conventional metal strip were also CDS tested in the manner described above.
  • the nominal size of these sensors was 1.0 inch x 3.0 inch.
  • the thicknesses of the sensing and reference elements on the 7075-6 aluminum sensors were 0.004 inch and 0.008 inch; whereas, the thickness of the steel elements were 0.003 inch for two sensors and 0.010 inch for two sensors.
  • reference 6a represents 0.004 inch Aluminum (S/F); 6b represents 0.008 inch Aluminum (S/F); 6c represents 0.004 inch Aluminum (T/H); 6d represents 0.008 inch Aluminum (FMG); and 6e represents 0.008 inch Aluminum (T/H).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Immunology (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Ecology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Environmental Sciences (AREA)
  • Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)

Abstract

Un système de contrôle de la corrosion permet de détecter et de contrôler plus facilement à distance la corrosion de matériaux. Des capteurs qui réagissent à un environnement corrosif similaire à celui du matériau que l'on veut contrôler sont placés dans des endroits isolés et connectés à un système central de commande par des câbles blindés. Le système comprend une carte contrôleur, des cartes doubles multiples de préamplification, un ensemble de batteries, des capteurs et les câbles correspondants. La carte contrôleur comprend un microcontrôleur, une mémoire, un circuit de conversion de données et d'autres circuits de commande. Les cartes doubles de préamplification contiennent des amplificateurs multiples de mesure de précision, des circuits de filtrage et de conversion de tension. Le système fonctionne sur la base du principe selon lequel la corrosion d'un conducteur métallique provoque une augmentation correspondante de la résistance électrique à travers la section transversale du conducteur. On peut détecter et contrôler ce changement de résistance en faisant passer un courant constant connu dans le conducteur et en comparant la tension dans le conducteur avec celle d'un conducteur contrôlé de référence. Le conducteur de référence n'est pas exposé à l'environnement corrosif. A mesure que le conducteur de test est corrodé, on mesure de faibles augmentations de la tension à travers l'élément par rapport au matériau de référence. Les signaux résultants sont multipliés et filtrés jusqu'à un niveau détectable et sont traités par le contrôleur sous la forme de points de données enregistrés en mémoire.
PCT/US1993/009617 1992-10-09 1993-10-08 Systeme de controle de la corrosion WO1994009354A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU53250/94A AU5325094A (en) 1992-10-09 1993-10-08 Corrosion monitor system

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US95880592A 1992-10-09 1992-10-09
US07/958,805 1992-10-09
US08/134,292 1993-10-08
US08/134,292 US5446369A (en) 1992-10-09 1993-10-08 Continuous, automatic and remote monitoring of corrosion

Publications (1)

Publication Number Publication Date
WO1994009354A1 true WO1994009354A1 (fr) 1994-04-28

Family

ID=26832183

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1993/009617 WO1994009354A1 (fr) 1992-10-09 1993-10-08 Systeme de controle de la corrosion

Country Status (3)

Country Link
US (1) US5446369A (fr)
AU (1) AU5325094A (fr)
WO (1) WO1994009354A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2286844A (en) * 1994-02-25 1995-08-30 Rohrback Cosasco Syst Inc Wellbore monitoring apparatus
US5702433A (en) * 1995-06-27 1997-12-30 Arrow International Investment Corp. Kink-resistant steerable catheter assembly for microwave ablation
WO2001042764A2 (fr) * 1999-12-10 2001-06-14 Vn-Instrument I/S Procede et appareil pour mesurer un taux cumule et immediat d'une perte materielle ou d'un gain materiel
US6861853B2 (en) 2000-03-14 2005-03-01 British Nuclear Fuels Plc Investigating corrosion
US6888359B2 (en) 2000-03-14 2005-05-03 British Nuclear Fuels Plc Investigating current
US6982563B2 (en) 2000-11-09 2006-01-03 British Nuclear Fuels Plc Monitoring of corrosion induced loss of material by means of a plurality of electrical resistance measurements (field signature method, electrical resistance tomography)
GB2454778A (en) * 2007-11-16 2009-05-20 Boeing Co Corrosion detecting structural health sensor
US7621193B2 (en) 2007-11-16 2009-11-24 The Boeing Company Fracture detecting structural health sensor
US8400171B2 (en) 2007-11-16 2013-03-19 The Boeing Company Transmission line moisture sensor
DE102012218925A1 (de) * 2012-09-10 2013-08-14 Siemens Aktiengesellschaft System zur Erfassung des Korrosionszustands
GB2571405A (en) * 2018-12-13 2019-08-28 Hevasure Ltd Optical corrosion sensor
GB2572090A (en) * 2018-12-13 2019-09-18 Hevasure Ltd Optical corrosion sensor

Families Citing this family (42)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2216079C (fr) 1995-03-14 2006-05-16 Profile Technologies, Inc. Detection des anomalies de surface d'elements conducteurs allonges par analyse d'impulsions de propagation
US5576481A (en) * 1995-10-02 1996-11-19 Ashland, Inc. Method and apparatus for detecting microbiological fouling in aqueous systems
AU7375796A (en) * 1995-09-29 1997-04-30 Ashland Inc. Method and apparatus for detecting microbiological fouling in aqueous systems
WO1997032219A1 (fr) 1996-02-27 1997-09-04 Profile Technologies, Inc. Appareil et procede pour tester des canalisations
US5999107A (en) * 1997-11-12 1999-12-07 Institute Of Gas Technology Remote cathodic protection monitoring system
US6131659A (en) * 1998-07-15 2000-10-17 Saudi Arabian Oil Company Downhole well corrosion monitoring apparatus and method
GB2349221B (en) 1999-04-19 2003-10-15 Cormon Ltd Electrical resistance sensor and apparatus for monitoring corrosion
KR100361644B1 (ko) * 1999-10-28 2002-11-21 한국수력원자력 주식회사 무선에 의한 ａｃｓｒ전선 내부부식 검출 방법 및 장치
US6625570B2 (en) 2000-06-20 2003-09-23 Joseph J. Pierro, Jr. Synchronous detection and remote monitoring and regulating of cell potential for cathodic protection
KR100405590B1 (ko) * 2000-06-23 2003-11-15 김영식 유무선통신 시스템을 통한 부식과 방식상태의 원격 점검및 제어 시스템
WO2002046701A2 (fr) * 2000-12-08 2002-06-13 The Johns Hopkins University Plateforme de capteur sans fil multifonctionnel, systeme contenant cette plateforme et technique d'utilisation de celle-ci
US6556027B2 (en) * 2001-01-12 2003-04-29 Ondeo Nalco Company Low cost, on-line corrosion monitor and smart corrosion probe
US6809506B2 (en) 2001-03-26 2004-10-26 The United States Of America As Represented By The Secretary Of The Navy Corrosion sensor loudspeaker for active noise control
GB0213912D0 (en) * 2002-06-17 2002-07-31 Univ Manchester Method and apparatus fo monitoring corrosion
WO2004003255A2 (fr) * 2002-06-28 2004-01-08 Vista Engineering Technologies, L.L.C. Procede et appareil de surveillance a distance de la corrosion a l'aide d'echantillons
GB0222658D0 (en) * 2002-10-01 2002-11-06 Bae Systems Plc Corrosion sensing microsensors
GB0222656D0 (en) * 2002-10-01 2002-11-06 Bae Systems Plc Corrosion sensing microsensors
US6894512B2 (en) * 2003-03-24 2005-05-17 Israel Aircraft Industries Ltd. Method for detecting hidden corrosion and a sensor for use in the same
US7196529B2 (en) * 2003-05-06 2007-03-27 Profile Technologies, Inc. Systems and methods for testing conductive members employing electromagnetic back scattering
US7642790B2 (en) * 2003-05-06 2010-01-05 Profile Technologies, Inc. Systems and methods for testing conductive members employing electromagnetic back scattering
WO2004102056A2 (fr) * 2003-05-06 2004-11-25 Profile Technologies, Inc. Systemes et procedes de test non destructif d'elements conducteurs au moyen de la retrodiffusion electromagnetique
US7034553B2 (en) * 2003-12-05 2006-04-25 Prodont, Inc. Direct resistance measurement corrosion probe
US7185531B2 (en) * 2003-12-11 2007-03-06 Siemens Power Generation, Inc. Material loss monitor for corrosive environments
US20050148081A1 (en) * 2004-01-06 2005-07-07 Braunling Russell D. System and method for corrosion maintenance scheduling
US7145453B2 (en) * 2004-09-02 2006-12-05 The Dow Chemical Company Harmonic wireless transponder sensor and method
US7061255B1 (en) * 2004-11-24 2006-06-13 Honeywell International Inc. Corrosion monitoring system
WO2009016594A2 (fr) * 2007-08-02 2009-02-05 Nxp B.V. Détecteur d'humidité basé sur une corrosion progressive du matériau exposé
US7675295B2 (en) * 2007-09-05 2010-03-09 The Board Of Regents For Oklahoma State University Passive wireless corrosion sensor
US7913570B2 (en) 2008-03-08 2011-03-29 Texas Research International, Inc. Environmental damage sensor
US8723534B2 (en) 2011-01-10 2014-05-13 International Business Machines Corporation Methods and apparatus for detection of gaseous corrosive contaminants
US10830689B2 (en) * 2014-09-30 2020-11-10 Rosemount Inc. Corrosion rate measurement using sacrificial probe
JP2017003376A (ja) * 2015-06-09 2017-01-05 Ｊｆｅスチール株式会社 腐食センサおよび腐食量の測定方法
US9927853B2 (en) 2015-09-28 2018-03-27 Dell Products, Lp System and method for predicting and mitigating corrosion in an information handling system
US10753852B2 (en) 2016-05-10 2020-08-25 Saudi Arabian Oil Company Smart high integrity protection system
US10330586B2 (en) * 2016-07-20 2019-06-25 Honeywell International Inc. Corrosion monitor
US10823439B2 (en) * 2016-12-14 2020-11-03 Dell Products L.P. Systems and methods for reliability control of information handling system
US11261726B2 (en) 2017-02-24 2022-03-01 Saudi Arabian Oil Company Safety integrity level (SIL) 3 high-integrity protection system (HIPS) fully-functional test configuration for hydrocarbon (gas) production systems
US10570712B2 (en) 2017-04-17 2020-02-25 Saudi Arabian Oil Company Protecting a hydrocarbon fluid piping system
CN109138982B (zh) * 2018-11-16 2023-09-26 美钻深海能源科技研发（上海）有限公司 水下装备生物腐蚀自动安全关井系统
US11078755B2 (en) 2019-06-11 2021-08-03 Saudi Arabian Oil Company HIPS proof testing in offshore or onshore applications
BR102020006687A2 (pt) * 2020-04-02 2021-10-13 Jefferson Carlos Tasca Central de integração e aplicativo para módulos anti-corrosão e método de instalação para proteção anti-corrosiva em superfícies metálicas e sistema de gerenciamento em tempo real
RU205642U1 (ru) * 2021-04-21 2021-07-26 Федеральное государственное автономное образовательное учреждение высшего образования "Южно-Уральский государственный университет (национальный исследовательский университет)" ФГАОУ ВО "ЮУрГУ (НИУ)" Выносная мембрана с функцией диагностики технического состояния разделительной диафрагмы

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2834858A (en) * 1956-12-18 1958-05-13 Pure Oil Co Corrosion testing probe
DE2919642A1 (de) * 1978-10-02 1980-04-03 Shiro Haruyama Verfahren und vorrichtung zum messen des korrosionsgrades von elektrisch leitenden, korrodierbaren metallen
GB2064124A (en) * 1979-11-24 1981-06-10 Sensors & Systems Ltd Corrosion monitoring system
GB2080537A (en) * 1980-07-14 1982-02-03 Shell Int Research Temperature compensation in electrical resistance corrosion measurement
WO1991006854A1 (fr) * 1989-11-04 1991-05-16 Natural Environment Research Council Methode et appareil pour analyser l'etat physique d'un terrain

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2824283A (en) * 1956-12-31 1958-02-18 Pure Oil Co Corrosion meter
US3067386A (en) * 1958-08-29 1962-12-04 Standard Oil Co Automatically temperature-compensated corrosion measurements
US3047847A (en) * 1958-12-12 1962-07-31 Pure Oil Co Device for remotely indicating corrosion
US3936737A (en) * 1975-04-10 1976-02-03 C.M.S. Inc. Corrosion monitoring system
US4019133A (en) * 1975-12-29 1977-04-19 Gulf Research & Development Company Corrosion detecting and monitoring apparatus
US4217544A (en) * 1978-10-16 1980-08-12 Shell Oil Company Method and apparatus for improved temperature compensation in a corrosion measurement system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2834858A (en) * 1956-12-18 1958-05-13 Pure Oil Co Corrosion testing probe
DE2919642A1 (de) * 1978-10-02 1980-04-03 Shiro Haruyama Verfahren und vorrichtung zum messen des korrosionsgrades von elektrisch leitenden, korrodierbaren metallen
GB2064124A (en) * 1979-11-24 1981-06-10 Sensors & Systems Ltd Corrosion monitoring system
GB2080537A (en) * 1980-07-14 1982-02-03 Shell Int Research Temperature compensation in electrical resistance corrosion measurement
WO1991006854A1 (fr) * 1989-11-04 1991-05-16 Natural Environment Research Council Methode et appareil pour analyser l'etat physique d'un terrain

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2286844A (en) * 1994-02-25 1995-08-30 Rohrback Cosasco Syst Inc Wellbore monitoring apparatus
US5627749A (en) * 1994-02-25 1997-05-06 Rohrback Cosasco Systems, Inc. Corrosion monitoring tool
GB2286844B (en) * 1994-02-25 1997-09-10 Rohrback Cosasco Syst Inc Wellbore monitoring apparatus
US5702433A (en) * 1995-06-27 1997-12-30 Arrow International Investment Corp. Kink-resistant steerable catheter assembly for microwave ablation
WO2001042764A2 (fr) * 1999-12-10 2001-06-14 Vn-Instrument I/S Procede et appareil pour mesurer un taux cumule et immediat d'une perte materielle ou d'un gain materiel
WO2001042764A3 (fr) * 1999-12-10 2001-11-08 Vn Instr I S Procede et appareil pour mesurer un taux cumule et immediat d'une perte materielle ou d'un gain materiel
US6861853B2 (en) 2000-03-14 2005-03-01 British Nuclear Fuels Plc Investigating corrosion
US6888359B2 (en) 2000-03-14 2005-05-03 British Nuclear Fuels Plc Investigating current
US6982563B2 (en) 2000-11-09 2006-01-03 British Nuclear Fuels Plc Monitoring of corrosion induced loss of material by means of a plurality of electrical resistance measurements (field signature method, electrical resistance tomography)
GB2454778A (en) * 2007-11-16 2009-05-20 Boeing Co Corrosion detecting structural health sensor
US7621193B2 (en) 2007-11-16 2009-11-24 The Boeing Company Fracture detecting structural health sensor
GB2454778B (en) * 2007-11-16 2010-10-27 Boeing Co Corrosion detecting structural health sensor
US8054092B2 (en) 2007-11-16 2011-11-08 The Boeing Company Corrosion detecting structural health sensor
US8400171B2 (en) 2007-11-16 2013-03-19 The Boeing Company Transmission line moisture sensor
DE102012218925A1 (de) * 2012-09-10 2013-08-14 Siemens Aktiengesellschaft System zur Erfassung des Korrosionszustands
GB2571405A (en) * 2018-12-13 2019-08-28 Hevasure Ltd Optical corrosion sensor
GB2572090A (en) * 2018-12-13 2019-09-18 Hevasure Ltd Optical corrosion sensor
GB2571405B (en) * 2018-12-13 2020-10-28 Hevasure Ltd Optical corrosion sensor
GB2572090B (en) * 2018-12-13 2020-10-28 Hevasure Ltd Sample for use in an optical corrosion sensor

Also Published As

Publication number Publication date
US5446369A (en) 1995-08-29
AU5325094A (en) 1994-05-09

Similar Documents

Publication Publication Date Title
US5446369A (en) Continuous, automatic and remote monitoring of corrosion
US7541817B2 (en) Method and a system of diagnosing corrosion risk of a pipe or a pipeline in soil
CA2426908C (fr) Dispositif de mesure de la corrosivite a compensation thermique
US20170205333A1 (en) Measurement systems and methods for corrosion testing of coatings and materials
Xia et al. Electrochemical probes and sensors designed for time-dependent atmospheric corrosion monitoring: fundamentals, progress, and challenges
US6623616B1 (en) Corrosive environment monitor and methods regarding same
Demo et al. Development of a wireless miniaturized smart sensor network for aircraft corrosion monitoring
WO2000034760A1 (fr) Technique de bruit electrochimique pour la corrosion
JPH06186196A (ja) 腐蝕センサー、および表面の腐蝕を測定する装置および方法
RU2685055C1 (ru) Способ мониторинга углекислотной коррозии в промысловых газопроводах и устройство для его осуществления
Demo et al. Diagnostics and prognostics for aircraft structures using a wireless corrosion monitoring network
Demo et al. Wireless corrosion monitoring for evaluation of aircraft structural health
Sternhagen et al. A novel integrated acoustic gas and temperature sensor
Cooper Sensing probes and instruments for electrochemical and electrical resistance corrosion monitoring
EP2762855B1 (fr) Testeur et procédé pour l'essai de niveau d'inhibiteur de corrosion
EP0287348A2 (fr) Surveillance in situ de la vitesse de corrosion de métaux polarisés ou non
Zou et al. Characterization of the conduction mechanisms in adsorbed electrolyte layers on electronic boards using AC impedance
Stropki et al. Monitoring Corrosion with an Automated electrical resistance corrosion probe monitoring system
US10151683B2 (en) Corrosion sensor using electrical continuity
Schoess et al. Smart aircraft fastener evaluation (SAFE) system: a condition-based corrosion detection system for aging aircraft
Murray et al. Evaluation of Electrochemical Noise to Monitor Corrosion for Double Hull Applications
Miksic et al. VCI's for Mitigating Electronic Corrosion
McIntyre et al. Resistance measurements on thin-film substrates as a technique for studying the deterioration of coated metals
JP2003194892A (ja) 環境試験装置および環境試験装置の汚染検知方法
Rocchini A computer code for detecting deterioration of organic coatings through impedance measurements

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU CA JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA