Unfortunately, this air-tight seal is often hard to maintain, especially if passengers want to walk between cars.

但不幸的是，这种高气密的设备不容易保养维护，特别是当乘客们想要在车与车之间走动时显得更为困难。

youdao

This review gives working mechanism of disc reactor shaft seal and points out the major factors that could improve air-tight seal effect. Besides it introduces some improvements on shaft seal.

叙述了圆盘反应器轴封的工作原理，指出了影响轴封密封效果的主要因素并介绍轴封的改进措施。

youdao

Usage: suitable for air tight seal welding with pressure protection of microwave device, sensor, filter and components that used on spaceflight and guided missile that have high requirement.

用途：适用要求较高的微波器件，传感器，滤波器及航天，导弹上应用的元件气密性带压力保护的封焊。

youdao