Вестник МГТУ. 2018, №4.

Вестник МГТУ. 2018. Т. 21, № 4. С. 632-637. DOI: 10.21443/1560-9278-2018-21-4-632-637 with heated air installed at a distance of no more than 100 mm. When heated, the temperature of the sealant front surface does not exceed 50-60 °C. The wind flow speed produced with the blow dryer (heater) reaches tens of meters per second. Fig. 1. Testing scheme for quality control of a cable pressure seal: 1 - blow drier; 2 - bulkhead (wall); 3 - sealant in the bushing; 4 - thermovision camera; 5 - air permeable penetration defect of the sealant; 6 - localization of the high temperature site on the back surface of the sealant Рис. 1. Схема проведения испытаний для контроля качества кабельного гермоввода: 1 - фен (нагнетатель воздуха); 2 - переборка (стенка); 3 - герметик в проходной втулке; 4 - тепловизор; 5 - воздухопроницаемый сквозной дефект герметика; 6 - локализация участка с повышенной температурой на задней поверхности герметика Fig. 2. External view of the cable inlet back surface with a flat penetration defect (0.1 mm thick, 4 mm high, 57 mm long) Рис. 2. Внешний вид задней поверхности модели кабельного гермоввода с плоским сквозным дефектом толщиной 0.1 мм, высотой 4 мм, длиной 57 мм After blowing the sealant front surface with warm air for several minutes (up to two or three minutes), the back surface temperature is continuously monitored with a thermovision camera in order to record the thermal wave passage from the front to the rear surface. The FLUKE Ti400 thermovision camera is used to record the temperature of the back (non-irradiated) surface and localize the defects on the back surface. During the testing process, thermograms are analyzed after 15-30 s within the next 15-20 min depending on the thickness of the sealant and the size of the penetration defects. The results of thermal imaging of the object under study have been processed using the software attached to the thermovision camera. The temperature of the cable inlet back surface T b was monitored. Values of the maximum (max), average (av), and minimum (min) temperatures of the object rear surface are estimated over time, as well as localization of the observed sealant defects (Fig. 3, 4). Fig. 4 shows an example of a histogram after image processing using the specialized software of the "FLUKE Ti400" thermovision camera. The value of the ambient temperature is within T 0 = 21-22 °С. Analysis of a series of sequential thermograms (Fig. 3, a ) shows that the highest surface temperature is found in the defect area, e. g. in Fig. 3, b : T bmax = 22.14 °C, T bav = 22.16 °C. Similarly, in Fig. 4 the thermogram shows the values of T bmax = 29.19 °C, T bav = 25.88 °C, T bmin = 21.95 °C at the air temperature T 0 = 21 °C. The temperature rise in the area of the analyzed penetration defect (Fig. 4, b ) reaches D T bmax = 7-8 °C. 633