... .Strong, simple construction 4.Compact body saves space Spherical blowout preventers (API 16A series) Working path ( mm ) 180,230,280, ... life.USAGE:•Annular blowout preventer uses and hydraulic control systems supporting the use of, when within the well drilling tool, can ... of the annular space; when the wells without drilling tool, can fully closed wellhead. API 16A annular/spherical blowout preventer