Detection thermography

Active thermography is a contactless NDE technique that consists in the detection of infrared emission after the transient thermal excitation of the inspected structure. 

Fig. 4. Sensitivity for the detection of CO using spectral thermography as a function of absorbing path length. Detector NEP = 30 pW, J = 1.0 mW/cm, A = 1.5E — 5 cm, samples = 60, number of detectors = 600, G = 6.6E5 ppm-cm center wavelength = 4.65 /im spectral bandwidth = 0.2 fim.

Thermography is a predictive maintenance technique that can be used to monitor the condition of plant machinery, structures and systems. It uses instrumentation designed to monitor the emission of infrared energy, i.e. temperature, to determine their operating condition. By detecting thermal anomalies, i.e. areas that are hotter or colder than they should be, an experienced surveyor can locate and define incipient problems within the plant. 

Inclusion of thermography into a predictive maintenance program will enable you to monitor the thermal efficiency of critical process systems that rely on heat transfer or retention electrical equipment and other parameters that will improve both the reliability and efficiency of plant systems. Infrared techniques can be used to detect problems in a variety of plant systems and equipment, including electrical switchgear, gearboxes, electrical substations, transmissions, circuit breaker panels, motors, building envelopes, bearings, steam lines, and process systems that rely on heat retention or transfer. 

Keywords. Enzymes, Mass spectrometry, IR-thermography, Optical detection. Fluorescence spectroscopy... 

Holzwarth, A. and Maier, W.F. (2000) Catalytic phenomena in combinatorial libraries of heterogeneous catalysts detection of activation and deactivation by emissivity-corrected IR thermography. Platinum Met. Rev., 44, 16. 

The first array-based technique was designed specifically to study reactions on solid phase catalysts as IR thermography.9,19 This approach utilizes IR sensitive FPA detectors to measure the temperature of catalysts under reaction conditions. This approach has the advantages of a theoretical high thermal sensitivity, typically several tens of millikelvin, and the ability to study both endothermic and exothermic reactions. The main disadvantage of this approach, however, is the lack of chemical information. It must be assumed that the temperature change is associated entirely with the desired reaction pathway. The presence of unexpected side reactions will not be detected in this approach, as long as they have similar thermal behavior as the reaction under study. 

It is also possible to partially alleviate the problem of chemical insensitivity by incorporating narrow bandpass filters into the optical setup.20 Thus, by choosing an appropriate frequency region, it becomes possible to detect the presence of a particular reactant or product species. While this adds some measure of chemical sensitivity to the thermography approach, it is only capable of monitoring one species at a time. Additionally, the success of this approach relies upon the fact that the spectral bands of the desired species do not overlap with any other species and that unexpected reaction products that have spectral contributions in the region of interest are not present. 

Taylor and Morken extended the use of IR-thermography to the monitoring of the change in the heat of reaction on and in the surroundings of a bead carrying an active catalyst (Figure 5.4.4) [13]. In a search for acylation catalysts an encoded library of 3150 different potential nucleophilic catalysts was prepared by the split-and-mix procedure and tested for their acylation properties. The library beads were spread in a reaction solution of chloroform-ethanol-triethylamine-acetic anhydride, 40 6 6 3, and monitored with an IR camera. Whereas no detectable thermal... 

Successful rotating equipment Predictive Maintenance Programs require several elements. Typical elements include an effective lubrication program with oil analysis to detect residual metal particles, thermography, machine monitoring instrumentation, repair specifications, repair history records, advanced training of mechanics, and the use of data management computers. [10]... 

Holzwarth, A. Schmidt, H.-W. Maier, W., Detection of catalytic activity in combinatorial libraries of heterogeneous catalysts by IR thermography, Angew. Chem. Int. Ed. 1998,37, 2644—2647... 

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