Protection of heat pipes from freeze damage

摘要

Disclosed is a heat pipe which is protected from damage due to freezing by the addition of small amount of a liquid such as an alcohol to its working fluid. Ethanol/water mixtures having ethanol concentrations from about 1 to 7.5 percent by volume are found to produce a relatively weak crystal solid during freezing in a heat pipe so that the weak solid breaks up and expands without rupturing a wall or joint of the heat pipe. Heat transfer and operating characteristics of the heat pipe are not degraded due to the presence of specified amounts of the additive.