Chauvin Arnoux 1875 User Manual
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Chauvin Arnoux 1875 User Manual

Chauvin Arnoux 1875 User Manual

Thermography bench
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GB – User's Manual
C.A 1875
Thermography bench

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  • Page 1 GB – User’s Manual C.A 1875 Thermography bench...
  • Page 2 C.A 1875 You have just purchased a C.A 1875 thermography tutorial bench and we thank you for your confidence. For best results from your instrument: read these operating instructions carefully, • • observe the precautions for use MEANINGS OF THE SYMBOLS USED Selective sorting of wastes for the recycling of electrical and electronic equipment within the European Union.

  • Page 3: Table Of Contents

    C.A 1875 CONTENTS 1. INTRODUCTION ....................4 2. PRESENTATION ....................5 3. CHARACTERISTICS ................... 7 ............7 ENERAL CHARACTERISTICS OF THE BENCH ................ 8 HARACTERISTICS OF THE FUSE 4. COMMISSIONING .................... 8 5. MANIPULATIONS .................... 9 THERMAL TRANSFERS ................9 5.1.1...

  • Page 4: Introduction

    C.A 1875 1. INTRODUCTION Infrared thermography detection technology has become an essential means of guaranteeing the safety of industrial production conditions. It is used in sectors of industry as varied as metallurgy and steel-making, electric power, the oil industry, automation, the extraction of natural gas, the transport industry, and other professions active in fire fighting and border surveillance.

  • Page 5: Presentation

    The objective is to make people aware that an infrared camera is a precision measurement tool that requires much training and experience to use correctly. The C.A 1875 tutorial bench comprises a hot plate with several targets having different surface conditions and made of different materials, along with test screens that are affixed to the front of the bench using magnets.
  • Page 6 C.A 1875 Presentation of the C.A 1875 thermography tutorial bench: 1: Hot plate 2: LEDs indicating rising or falling temperature 3: On / Off switch 4: Power cord connection 5: Fuse compartment 6: 10: Plates of different materials 7: Cover protecting the bench...

  • Page 7: Characteristics

    C.A 1875 Presentation of the test screens Test screen no. 2: Test screen no. 1: Slits of variable width Plexiglas pane Presentation of the hot targets Plate 1: Plate 4: Polish steel Red copper Plate 2: Plate 5: Stainless steel...

  • Page 8: Characteristics Of The Fuse

    Rating: 0.5 A fast-blow – 250 V 4. COMMISSIONING The C.A 1875 thermography tutorial bench must be placed on a flat, level surface. The hot plate must be perpendicular to the work top. Once the bench is in place, connect it to a mains outlet with an earth and power up using the On/Off button.

  • Page 9: Manipulations

    C.A 1875 T(°C) Regulation 60° Max Diagram of operation of the LEDs and of the temperature variation of the hot plate. When the bench is started up, L1 lights until the plate reaches approximately 55°C. When this temperature is reached, L2 lights and the plate cools to approximately 50°C.
  • Page 10 C.A 1875 Conduction. In physics, thermal conductivity is the parameter used to quantify the ability of a body to conduct heat. It represents the quantity of heat transferred per unit of area and per unit of time under the action of a temperature difference between the two ends of a sample of the body, and therefore in the presence of a temperature gradient.
  • Page 11 C.A 1875 Forced convection in which the flow of the fluid is forced by some mechanical device (pump or gravity for a liquid, blower for air). Forced convection is an undesirable phenomenon in infrared thermography. This is because forced convection cools the surface of a body without for all that altering its internal temperature.
  • Page 12 C.A 1875 Radiation: case of the full radiator or black body. Anybody at a temperature above 0 degree kelvin (absolute zero, or -273.15°C) emits electromagnetic radiation called thermal radiation. Infrared radiation is electromagnetic radiation of which the wavelength is between 700 nanometres and 1 millimetre.
  • Page 13 C.A 1875 The Stefan-Boltzmann law is used to quantify these exchanges. The energy E radiated by a body is written: E = S. σ. T With: E: radiated energy expressed in W/m². σ: Stefan-Boltzmann constant = 5.6703 x 10 S: area of the body expressed in m²...
  • Page 14 C.A 1875 The lower the emissivity, the lower the maximum of the curve. The Stefan-Boltzmann law then becomes: E = ε. S. σ. T The emissivity of a material is a characteristic of that material and of its surface condition. The more capable a body is of absorbing heat, the closer its emissivity to 1.

  • Page 15: Manipulations: Study Of The Influence Of Emissivity

    C.A 1875 5.1.2 Manipulations: study of the influence of emissivity Manipulation 1: Highlighting the problems of measurement on materials having different emissivities. Make sure that the temperature of the bench has been stable for a few moments. Aim the camera at the hot plate, making sure that you are correctly positioned in front of the bench.

  • Page 16: Study Of The Real Body

    C.A 1875 5.2 STUDY OF THE REAL BODY 5.2.1 Theory The black body is a theoretical object. The formulas given above can be applied to a real object only with a few corrections: real objects absorb only a fraction α of the incident radiation, reflecting a part ρ and transmitting a fraction τ.
  • Page 17 C.A 1875 Radiation of the object Reflected radiation of the environment on the object And the total radiation received by the camera is therefore: measured object reflected ε. σ. (T ρ . σ. (T object reflected Whence: = ε. σ. (T + ρ...

  • Page 18: Manipulations: Study Of The Influence Of Reflection And Transmission

    C.A 1875 5.2.2 Manipulations: study of the influence of reflection and transmission Manipulation 3: Highlighting of the problems of measurement linked to reflection phenomena Create a new folder. - Position the camera in front of the aluminium plate: shiny, having a low emissivity, and therefore strongly reflecting.
  • Page 19 C.A 1875 HFOV: horizontal angle VFOV: vertical angle Starting from this, IFOV can be defined by the equation: HFOV VFOV IFOV (°) = With: ndH: number of detectors on the horizontal of the matrix ndV: number of detectors on the vertical of the matrix...
  • Page 20 C.A 1875 Diagram summing up the various concepts: Rectangular thermal view square Δs (seen by the rectangular matrix) (seen square detector) HFOV IFOV VFOV Application: see appendix 3, exercise 6. Measurement Spatial Resolving Power (PRSM). For temperature measurements, as opposed to thermal imaging, it is necessary to consider the metrological character of the camera.
  • Page 21 C.A 1875 Case no. 1: The wire is the size of 1 IFOV. In reality, there is a greater risk of To be sure of making a valid having this configuration: measurement, the wire must be positioned like this: No detector is completely covered:...

  • Page 22: Manipulation: Study Of Spatial Resolution

    C.A 1875 We are still not sure of making a valid temperature measurement. This configuration too is unrealistic!! Case no. 3: The wire is the size of 3 IFOVs. Anywhere the wire is placed, there will necessarily be at least one detector covered! The measurement is therefore reliable.

  • Page 23: Manipulations On Software

    C.A 1875 - Position the RayCAm 30 cm from screen no. 2. Make a thermogram of each series of slits. Using the cursors, determine the temperature of each slit. What is your conclusion? - Position the RayCAm 80 cm from screen no. 2.
  • Page 24 C.A 1875 - Create one table zone per thermogram. Enter the following elements in the table: number and emissivity of IR image, temperature and emissivity of the points. - Modify the emissivity of the points until you obtain the temperature of the black plate.

  • Page 25: Thermography In Practice

    C.A 1875 5.5 THERMOGRAPHY IN PRACTICE 5.5.1 Fault determination modes. Absolute thermography This mode provides information about the condition of a component or of a material given its operating conditions at the time. The question that must then be asked is: is this below or above the maximum...

  • Page 26: Applications

    C.A 1875 Difference (ΔT) based on comparison of identical components working under the Criterion of severity same load conditions Possible. Keep under surveillance < 10°C until the next maintenance already planned Intermediate. Corrective measures 10°C to 20°C to be set in place, scheduled (~ 3 months) Serious.
  • Page 27 C.A 1875 The methodology to be applied for an electrical maintenance inspection is the following: A systematic sweep of the whole electrical installation is performed (if needed and where possible, a view from the back is taken). The systems examined are in operation, and the elements making up the electrical installation are under normal load.

  • Page 28: Producing A Q19 Report

    C.A 1875 A single image shows us the soundness of the electric motor, of its power supply (cables), of the bearings, and possibly of the alignment. It remains to be determined how urgent maintenance is. Application: building heating and cooling...
  • Page 29 C.A 1875 • Information about the existence of locations, zones, or rooms where there is a particular fire or explosion risk. Agree to:  • Have the thermographer accompanied in the installations by a technician belonging to the relevant department.
  • Page 30 THERMOGRAPHIC INSPECTION Anomaly sheet no. 1 C.A 1875 Station: Equipment: Load: 100% IR Info Value IrNo dist envtmp Date 2003-9-3 Time 12:52:39 Label Value Diagnostic: Max:Temp 101.38 Max:ems Recommendation: Max:dist CONCLUSION: ........................Checked by: Mr....Inspected on: ../../2... by Mr .....

  • Page 31: Application

    C.A 1875 5.6.2 Application Using an electrical cabinet present in the room, make thermograms of the installation and prepare a report based on the Q19 model. 6. MAINTENANCE The manufacturer cannot be held liable for any accident that occurs following a repair done by a party other than its customer service department or an approved repairer.

  • Page 32: Change Of Fuse

    C.A 1875 6.2 CHANGE OF FUSE Disconnect the device from the power network; Between the plug and the On/Off button, press the two tabs to withdraw the fuse holder. To preserve the same level of safety, replace the defective fuse only by a fuse having strictly identical characteristics.

  • Page 33: Appendix 1: Determination Of Emissivity

    C.A 1875 APPENDIX 1: DETERMINATION OF EMISSIVITY The relevant standard is ASTM E1933-99A: Let S1 be the surface area of the material of which it is desired to determine the emissivity. Apply to S1 a coat of black paint S2 of which the emissivity is known.

  • Page 34: Appendix 2: Determination Of Reflected Temperature

    C.A 1875 APPENDIX 2: DETERMINATION OF REFLECTED TEMPERATURE The relevant standard is ASTM E1933-99A: 1) A sheet of ordinary aluminium foil, crumpled and flattened, is placed as close as possible to the scene viewed, in the same orientation with respect to the camera.

  • Page 35: Appendix 3: Application Exercises

    C.A 1875 APPENDIX 3: APPLICATION EXERCISES Exercise 1 Highlighting of conduction in IR thermography: Thermogram 1 Thermogram 2 Comment on these two images. Exercise 2 Highlighting of the problems of forced convection in IR thermography. Thermogram made in high wind Thermogram made in still air Comment on these two images.
  • Page 36 C.A 1875 Exercise 3 A spherical black body having a radius of 5 cm emits 230 W of radiation. What is the temperature of this body? What is the wavelength corresponding to the maximum of radiated energy? Exercise 4: Based on estimates made on Earth, the area of the sun is 6.1 x 10 and its radiated power is 3.9 x 10...
  • Page 37 C.A 1875 Exercise 6 From the characteristics of the RayCAm, determine the IFOV of the camera in mrad and in …mm@1m: For the vertical elements of the matrix For the horizontal elements of the matrix What is the smallest area the camera can detect?
  • Page 38 C.A 1875 Exercise 10 Determine the degrees of urgency of maintenance of the thermograms below. Thermogram 1 52.8°C 45.5°C 45°C Thermogram 2 57.9°C 68°C 67.4°C Thermogram 3 45.5°C 51.6°C 44.7°C...
  • Page 39 C.A 1875 Thermogram 4 51.3°C 55.3°C 55.4°C Thermogram 5 43.2°C 24.9°C Thermogram 6 60.3°C 35.3°C...
  • Page 40 C.A 1875 Exercise 11 Determine the degrees of urgency of maintenance of the thermograms above assuming that: Thermogram 1 was made at 60% of nominal load Thermogram 2 was made at 90% of nominal load Thermogram 3 was made at 85% of nominal load...

  • Page 41: Appendix 4: Solutions

    C.A 1875 APPENDIX 4: SOLUTIONS Solution 1 Thermogram 1: This concerns the observation of a refractory using an infrared camera. The naked eye sees nothing. Normally, if the stack were correctly insulated, the temperature of the surface of the refractory should be uniform, and so its colour should be uniform.
  • Page 42 C.A 1875 Solution 3 Question a Stefan's law: P = S ε σ T With ε = 1 because black body σ = 5.68 x 10 Boltzmann's constant S = π R surface of a ball Whence: = P/S ε σ...
  • Page 43 C.A 1875 This analysis is of course false: it simply reveals a transmission problem! As it happens, it is not possible to observe and measure temperatures through glass! Whence this false measurement! Solution 6 Question a According to the definition of the IFOV: VFOV x π...
  • Page 44 C.A 1875 Solution 7 Question a The IFOV of the RayCAm is 2.2 mrad. The minimal focal length is 10 cm. The smallest zone that can be measured corresponds to 3 IFOV. We therefore find: = 3 x IFOV 10 cm Whence: = 0.66 mm...
  • Page 45 C.A 1875 Question b To be sure of making a valid measurement, the following value must not be exceeded: = 3 x Δs Cable In addition, based on the IFOV of the camera: at 1 m Δs = 2.2 mm at d Δs...
  • Page 46 C.A 1875 Solution 9 Question a The corresponding diameter d of the cable is: P = π x (d/2)² Therefore: d = ((4 x P)/π) To be sure of making a valid measurement, the following value must not be exceeded: = 3 x Δs...
  • Page 47 C.A 1875 Solution 10 Thermogram 1 From the temperatures of the cursors, let us determine the difference of temperature between P01 and P02: ΔT = T – T = 52.8 – 45.5 ΔT = 7.3°C Whence a degree of criticality of level 0, requiring surveillance.
  • Page 48 C.A 1875 Thermogram 6 From the temperatures of the cursors, let us determine the difference of temperature between P02 and P01: ΔT = T – T = 60.3 – 35.3 ΔT = 25°C Whence a degree of criticality of level 2; plan corrective action in from 1 to 3 months.
  • Page 49 C.A 1875 ΔT effective = ΔT raw x (100/85)² = 6.1 x (100/85)² = 8.5°C The degree of criticality is level 0; the evolution of the installation must be monitored. There is no significant influence of the load. Thermogram 4 We find the equation: ΔT effective = ΔT raw x (I nominal /I measured )²...

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