The dynamic seal between the submersible thruster impeller and the deceleration mechanism is a very important part of the host. Whether its structure is reasonable or not is directly related to the success or failure of the equipment diving work. At present, the most common structure at home and abroad is two single-end mechanical seals, one of which is built in the oil chamber and lubricated by mechanical oil; the other is externally placed in the sewage and arranged in an exposed arrangement and lubricated by the sewage. In practical applications, it is found that the reliability of this dynamic seal structure is not very satisfactory. The reason is that the single-end mechanical seal exposed in the sewage is easily invaded and damaged by suspended dirt, aquatic fibers, cloth yarns, etc., which affects the sealing effect. It causes water seepage and water leakage, and causes corrosion and rust of internal bearings, gears and other transmission components, causing malfunctions. In order to avoid this phenomenon and further improve the reliability of the seal, this is improved to an internal and external combined dynamic seal structure (see Figure 1).
Figure 1 Internal and external combined dynamic seal structure
The internal and external combined dynamic seal structure of the submersible thruster is also controlled by two dynamic seals. The internal channel is equipped with double-end mechanical seals, and the internal and oil-lubricated closed structure is the main seal; the external channel is equipped with dirt-retaining multi-lip seals, external , Water lubrication is an open structure. The multi-lip seal is a multi-lip structure with inner frame PTFE specially designed for the working conditions of the thruster. Its inner diameter is designed as a multi-lip. The lips tightly hug the drive shaft. The greater the water pressure, the better the sealing effect. The outer channel fouling multi-lip seal is the first pass of the seal, blocking the dirt and dirt in the sewage, protecting the inner channel mechanical seal from dirt damage, and forming a dynamic seal combination with the inner channel mechanical seal to block dirt And waterproof, clear function, reasonable structure, can ensure permanent and reliable sealing.