The two kinds of shaft seal have several disadvantages, for example, complicated control system, highly maintenance cost, serious contamination, more power consumption and lower stability.

浮环密封和接触式机械密封需要密封油及油液控制系统，其控制系统复杂、维护费用高、污染严重、能耗较大、稳定性较低；

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Hydrophobic coatings seal lens surfaces with an ultra-smooth polymer, making it easy to clean the eyeglass lenses from dirt, water or oily contamination can simply be wiped off.

加硬防水膜在镜片表面封上一层非常致密平滑的聚合物，使得镜片表面灰尘、水及油污清洁异常方便。

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