Structural characteristics of mechanical seal for cauldron
Mechanical seals are sealed by a pair or pairs of vertical to the shaft for relative sliding face in the fluid pressure and compensation mechanism under the action of elastic (or magnetic) stick together with auxiliary seal to achieve leakage sealing device.
A, B, C and D channels are the possible ways of fluid leakage in mechanical seals.C and D leakage channels are seals between stationary ring and gland respectively and between gland and shell, both of which are static seals.Channel B is the seal between the rotating ring and the shaft. When the end face is rubbed and worn, it can only follow the compensation ring along the axial direction for a small amount of movement. In fact, it is still a relatively static seal.Therefore, these leakage channels are relatively easy to plug.Static sealing elements are the most commonly used rubber o-ring or teflon v-ring, and as a compensation ring of the rotating ring or static ring auxiliary seal, sometimes with both elastic elements function of rubber, teflon or metal bellows structure.A channel is A rotating ring and the end of the stationary ring affixed to each other relatively sliding dynamic seal, it is the main seal in the mechanical seal device, but also the key to determine the mechanical seal performance and life.Therefore, the processing requirements for the sealing end face are very high. At the same time, in order to maintain the necessary lubrication film between the sealing end face, the unit area pressure on the end face must be strictly controlled. If the pressure is too high, it is not easy to form a stable lubrication film, which will accelerate the wear of the end face.If the pressure is too low, the leakage will increase.Therefore, in order to obtain good sealing performance and have enough life, in the design and installation of mechanical seals, must ensure that the end of the unit area pressure value in the most appropriate range.
Compared with soft packing seals, mechanical seals have the following advantages:
(1) sealing reliable in the long period of operation, the sealing state is very stable, the leakage is very small, according to rough statistics, the leakage is generally only 1/100 of the soft packing seal;
(2) long service life in oil, water media can generally reach 1 to 2 years or longer, in the chemical medium can usually reach more than half a year;
(3) Friction power consumption small mechanical seal friction power is only soft packing seal 10% ~ 50%.