API / JIS Swing Check Valve Product structural features Check valves are used in pipes under pressures between PN1.6~16.0MPa(Class150~2500Lb), working temperatures-196~60° C, They are used in industries include oil, chemistry, pharmaceutical, fertilizer, and power generation to prevent the backward flux of the media. The main structure features include: 1, The products feature a reasonable structure, reliable seal, good performance and nice modeling.