two-stage

The circumlittoral shelter forest system is divided into two stages.

山东沿海防护林体系建设主要目标分阶段。

The filter integrates two stages of coarse filters and one stage of fine filter, as well as a de-dust device by exhaust gas vacuation.

该滤清器由级粗过滤器和一级精滤器集合而成，并带有废气引射抽尘装置。

Through the research on petroleum and nature gas, design a multi-source heatpump of single and double effect lithium bromide, the two stage heatpump unit, process of nature gas liquefaction etc.

过对石油天然气物性的研究,利用热泵机的特点,设计多源单制冷供热热泵机、热泵机、级热泵机及天然气液化流程。