The spring type mechanical seal of common industrial rotary swivel joints can provide sealing isolation between liquid and gas medium or between medium and surrounding air. The spring of the rotary swivel joint is used to provide the initial internal sealing pressure. Once the joint starts to operate, it will be in a pressure-sealed state, and the spring will compensate for seal wear. The low air pressure or vacuum environment relies on spring thrust to seal. There are generally three types of the sealing forms of the rotary swivel joints:plane seals, spherical seals and elastomeric rotary seals.
1. Balanced seal of rotary swivel joint
With the improvement of industrial rotary swivel joint technology, the rotary swivel joint uses a balanced seal in the plane seal. Balanced sealed rotary swivel joints are usually used for liquid media (such as water, coolant, etc.), and can also be used to conduct water vapor or other gas media.
The balanced sealing technology keeps the medium pressure, thrust load and contact pressure of the sealing surface to a minimum. This reduces wear and extends the seal life of industrial rotary swivel joints. A spring is used to load and fix the sealing surface so that it cannot produce rotation and movement. It is this rotation and movement that makes the auxiliary seal prematurely aging, which in turn causes leakage of the rotary swivel joint. Balanced seals are usually supported by ball bearings.
2. Spherical seal of rotary swivel joint
Spherical seal is a sealing structure usually used in industrial rotary swivel joints. The basic principle is to realize the sealing through the contact surface of the spherical surface and the conical surface extruding each other, which has the characteristics of good sealing performance and convenient disassembly and assembly. In the spherical sealing structure, there are two main factors that affect its sealing performance: one is the processing quality of the spherical and conical surfaces; the other is the grinding accuracy of the spherical and conical surfaces.
3. The elastic cylinder seal of the rotary swivel joint
The sealing surface of the elastic cylinder seal is a narrow cylindrical surface, and the elastic body is used to compensate for wear. This kind of sealing mechanism has relatively high requirements for cylindrical processing, and the processing dimensions of the groove bottom, surface roughness, roundness, coaxiality, etc. must be strictly guaranteed.
4. The sealing ring of the rotary swivel joint
The sealing rings of rotary swivel joints is the main wearing part. When the seal ring of the industrial rotary swivel joint is in operation, the seal ring not only bears the pressure of the internal fluid medium but also bears the rotating torque generated by the operation of the outer pipe. Therefore, operating conditions such as vehicle speed, temperature and medium will affect the service life of the seal ring.
The above is an introduction to the sealing forms of the rotary swivel joint. To a considerable extent, the rotary swivel joint is actually just a sealed enclosure. Poor quality seal rings wear faster, leading to increased maintenance time, downtime, and repair costs. If the seal fails, the medium leakage will affect the heating or cooling efficiency of the equipment. The cost of replacing the sealing rings of rotary swivel joints is much smaller than the total economic loss after the seal fails.