Heat pipe is the use of evaporative refrigeration effect, because of the temperature difference between the two ends, so that the heat conduction quickly. The heat pipe is divided into two parts: the evaporating heating end and the condensing end. When the heated end starts to be heated, the liquid around the tube wall will vaporize instantaneously and generate steam. At this time, the pressure of this part will increase and the steam flow will flow to the condensing end under the traction of the pressure. When the vapor flow reaches the condensing end, it condenses into a liquid, at the same time, it also gives off a lot of heat, and finally returns to the heated end of evaporation with the help of capillary force and gravity to complete a cycle.

A typical gravity heat pipe is shown in the figure. A vacuum is first pumped into a closed pipe, in which a proper amount of working medium is filled and heated at the lower end of the heat pipe. The working medium absorbs heat and vaporizes into steam. Under the action of gravity, the condensate returns to the heated section along the inner wall of the heat pipe, and is heated again to vaporize, so the cycle repeats, continuously transferring heat from one end to the other end. Because of phase transition heat transfer, the heat resistance inside the heat pipe is very small.

Heat pipe has the advantage of very fast heat transfer speed, installed in the radiator can effectively reduce the heat resistance value, increase the heat dissipation efficiency, has a very high thermal conductivity, up to 100 times the thermal conductivity of pure copper, has the reputation of "thermal superconductor".

Heat pipe has the following advantages:

● Heat pipe cooling technology has the advantages of good cooling effect, relatively small thermal resistance, long service life, fast heat transfer. The thermal conductivity of heat pipe is more than 100 times that of common metal.

● Reversible heat transfer direction, no matter any end can become the evaporation end and condensation end;

● Excellent thermal responsiveness. The steam vaporized in the heat pipe can be transmitted close to the speed of sound, so as to effectively improve the thermal conductivity.

● Simple and compact structure, light weight, small volume, easy maintenance;

No power consumption, no noise, in line with the requirements of industrial "green";

● Can be used in the environment without gravity field.