08,26,2026 7 views
Magnetic fluid seals are used in rotating applications, where tiny magnetic particles are suspended on a carrier fluid such as glycerol, and the resulting magnetic fluid is filled into the sealing chamber. The shell is made of non-magnetic material, and the shaft is made of magnetic material. The magnetic poles on both sides of the magnet and the rotating shaft form a magnetic circuit. The magnetic flux density of the magnetic pole is high, the magnetic field strength is high, and the magnetic fluid is concentrated to form a magnetic fluid circular ring, which plays a sealing role. It can achieve zero leakage and wear without the need for an external lubrication system, and the precision requirements for the shaft are not high. Used under conditions of high-speed operation, high vacuum, and low temperature
Spiral seals are used in rotating applications, with a simple structure, low installation and manufacturing accuracy requirements, easy maintenance, and long service life. However, they need to be selected in the opposite direction to the rotation direction of the shaft. Suitable for low pressure media with a pressure less than 1-2 MPa and high viscosity media with a velocity less than 30 m/s, but a parking seal must be installed.
Maze spiral seal is used in rotating situations, and the difference from spiral seal is that the shaft sleeve is machined into threads and rotates in the opposite direction to the threads of the shaft. When the shaft rotates, the liquid increases turbulent friction between the spirals, thereby improving the sealing ability. The sealing effect is better than spiral sealing. Currently suitable for use on atmospheric distillation heavy oil pumps in atmospheric and vacuum distillation units.
Jet sealing is used in rotating situations, where fluid can be drawn out at high speed through the injector at the outlet of the pump, and the leaked fluid in the sealing chamber can be sucked into the inlet and outlet of the pump to achieve sealing, but a pump stop sealing device is required. The structure is simple, the license installation is convenient, and the sealing effect is good, but the volumetric efficiency is low. Suitable for low-temperature and low-pressure corrosive media without solid particles
Floating ring seals are used in cyclic applications, and floating rings can float radially on the shaft. Axial sealing relies on the narrow radial clearance between the floating ring and the shaft to generate throttling; Radial sealing is achieved by combining the floating ring with the floating sleeve on the shaft. The structure is simple but the sealing effect is poor, suitable for high-pressure and high-speed water pumps.
The combination of labyrinth spiral seal and mechanical seal is used in rotating situations, which reduces the sealing oil pressure and improves the service life of mechanical seals. Currently, it has been used in high-temperature and high-pressure situations such as atmospheric heavy oil pumps.
