Experiments were performed to investigate the characteristics of hollow glass microspheres as an insulating material and as an opacifying agent for other insulations. The thermal conductivity of the microsphere insulation was found to be about one and a half times that of stagnant air in the inevstigated temperature range (average insulation temperatures ranging from 75 to 250 degree C (170-480 degree F). Therefore, the insulating quality of the microspheres is comparable to that of fine powder insulations and superior to that of most fibrous insulations. It was also established that radiative transfer has a minor effect on the thermal conductivity of the microsphere insulations, so that additive opacifiers need not be employed. These characteristics, taken together with light weight, mechanical strength, fluidity, minimal airborne dispersion, high temperature capability, and moderate cost, cause microsphere insulations to be highly attractive for practical application.
|Original language||English (US)|
|Journal||American Society of Mechanical Engineers (Paper)|
|Issue number||76 -HT-OO|
|State||Published - Jan 1 1976|