Page
11
of
22
3.2
Thermal insulation from the environment
In high temperature environment the efficiency of cooling can be greatly improved by appropriate thermal
insulation of the camera and cables from the environment. This is especially important for the cables
which are not cooled as efficiently as the camera body. Various industrial thermally insulating protective
sleeves are available. In the figures below the following sleeves have been applied:
•
ADL Insulflex Thermosleeve B
o
Fiber glass sleeve (flexible)
o
Continuous temperature up to 540 °C
o
Suitable for inner insulation layers (three layers applied in the tests)
•
ADL Insulflex Pyrojacket
o
Fiber glass sleeve with silicone rubber coating
o
Continuous temperature up to 260 °C
o
Short-term (15 min) temperature up to 1090 °C
o
Momentary (15 sec) temperature up to 1650 °C
o
Suitable for the outermost insulation layer (one layer applied in the tests)
An alternative protective sleeve for Pyrojacket for the most challenging environments:
•
ADL Insulflex Pyreflect firesleeve
o
Aramid fiber blanket with aluminium coating
o
Reflects at least 90 % of radiant heat energy
o
Continuous temperature up to 340 °C
o
Short-term temperature up to 540 °C
o
Momentary (1 min) temperature up to 1650 °C
Before applying protective sleeves the proper cooling of electrical cables must be arranged. This can be
done by twisting the cooling hoses around the electrical cables as shown in Fig. 3.2.
Fig. 3.2. Twisting the cooling hoses around the electrical cables.
Since the cooling hoses can’t be twisted around the electrical cables right behind the camera, it is
important to wrap all hoses and cables tightly inside aluminium foil behind the camera. In Fig. 3.3 four
rounds of aluminium foil have been wrapped around the camera and all cables and hoses. The foil covers
roughly half of the camera housing and continues to the location where the cooling hoses can be properly
twisted around the electrical cables. Proper thermal contact to the camera housing is ensured by wrapping
Kapton tape tightly around the aluminium foil. Since the housing of the camera is kept cool by active
cooling, also the aluminium foil is kept cool and this keeps the cables cool in the region where the cooling
hoses
can’t be properly twisted around the cables.