According to the nature of the mechanical seal liquid, the insulating liquid can be lower than that of the mechanical seal.

According to the nature of the mechanical seal liquid, the insulating liquid can be lower than the filling liquid.

All types of double mechanical seal devices need to isolate the liquid system. They generally belong to the external closed-loop system, and the liquids used in them are generally different, but they must match the liquids in the process. The system consists of a reservoir located as close to the seal as possible. The range of design variations for these systems is very large. Some systems use a pump ring in the seal, while others use the principle of the thermosiphon effect. The liquid in the liquid storage tank often adopts the method of auxiliary heating or auxiliary cooling. In addition, an alarm device can be added to remind the staff to replace the liquid in time.

According to the nature of the mechanical seal liquid, the isolation liquid system can work at a pressure lower than or higher than that of the stuffing box.

In order to achieve the goal of zero leakage during the entire driving operation process, the sealing industry has also developed gas isolation seals. This type of seal uses inert gases such as nitrogen to replace the liquid isolation system. In the double seal with gas isolation, if the inside of the sealing surface fails, only the inert gas will leak, and the liquid inside will not leak, thus will not cause environmental pollution.