circular valve meaning in English

环形阀
环闸

The cavity above is composed of the wall of cavities and two layers films lies up and down , each of them has a layer of pzt chip . the cavities underside is composed of the wall of cavities , the film and a layer of class . there is circular valves lies in the import and export , and the material of the micropump films and the valves is silicon
提出了一种双腔微泵结构设计方案，这种泵分为上下两个泵腔，上面泵腔由腔壁与上下两层薄膜围成，每层薄膜上都有一层pzt片；而下面泵腔则由腔壁与围成上面泵腔的下层硅薄膜及一层玻璃围成，出入口处采用环形阀门结构，泵膜和阀片的材料为硅。