The high temperature environment can lead to a decrease in the hardness and strength of the rotary joint, and it is also possible that the impregnated substance can be resolved; At the same time, the fluid liquid film in the sealing gap will also vaporize due to high temperature. In the dry friction experiment, it can be known that the wear amount increases sharply with the increasing temperature in different carbon material tests; Of course, different friction pair materials can be selected to control the amount of wear, so as to ensure the sealing life of working in high temperature environments. However, it must be ensured that the temperature in the sealing gap must not be too high, otherwise the sealed liquid medium will partially vaporize; At this time, the thermal conductivity of the sliding friction pair has a very important impact, and it must be able to dissipate the heat generated by friction well, and the temperature increase that is not allowed not only leads to a large amount of wear, but also accelerates the aging of some sealing components and increases leakage loss.

For the circulation of high-temperature molten salt, heat transfer oil, steam high-temperature rotary joint, in order to extend the service life, the selection of materials with appropriate thermal conductivity is one of the first choice, but also take certain measures, such as taking balance load, improve the flow speed of fluid medium into and out, add heat dissipation circulating water device for sealing position on the shell, etc., so that the sealing component in the sealing cavity as much as possible to maintain the specified use temperature range, to avoid the harm and turbidity caused by inadmissible or improper temperature rise.

In the test, the wear of the friction pair of the rotary joint has changed greatly compared with the higher temperature environment. For example, a very wear-resistant friction pair composed of metal and graphite is in the case of pure dry friction (V_g=10m/s, P_g=15N/cm²), and its life can reach more than 4000h. However, when used to seal liquid oxygen, it is damaged in less than a few hours due to excessive wear and frictional heat that cannot be well dissipated. Fengrui Machinery has been summarizing the test data and parameters in the high temperature working environment, hoping to use the high-temperature rotary joint products in the ultra-high temperature working environment above 380 °C to make a qualitative breakthrough.