1. Single end face mechanical seal. Single end face mechanical seal structure is simple, the auxiliary equipment is few.
2. Double end face mechanical seal. The double end face seal is reliable and the service life is long, and a buffer chamber is arranged between the seal and the pump body. In order to make the sealing liquid pressure can be adjusted according to the change of the liquid discharging pressure, the pressure device, the cooling tank and other equipment are generally equipped. The double end face seal structure is complex, the auxiliary equipment is much, and when the internal seal failure, the sealing liquid will leak into the liquefied gas, which in some chemical production will cause unsafe accident. Therefore, with the improvement of single end face seal and the improvement of technology, the use of single end face seal on the low temperature pump increases year by year. Has been used to the temperature is equal to -100 degrees Celsius occasions, etc..
3. Double end face series mechanical seal. In many occasions, especially in long-distance pipeline transportation, the hope can be found at the beginning of the seal damage and subsequent leakage. In this case, the two end face series seal. The inner side of the sealing function quite within a single terminal cartridge seal, seal cavity is only filled with liquid from the tank, without pressure. So of the inboard seal lubrication is provided by the process media, and is not affected by liquid liquid, once the inner seal failure, resulting in sealed cavity pressure increases, which can by the tank pressure gauge display, recording or alarming for timely maintenance. And the outer seal can bear the function of the sealing of the shaft and the leak fluid.
