The utility model provides an ellipsoid conduit head bottom of case ring flange installs equipment additional, including interior strutting arrangement, it includes revolving stage and a plurality of support element, and support element lays on the revolving stage, and including radial slide, a radial slide side is certain contained angle setting with the revolving stage, is provided with slope slide on this side, is provided with the supporting disk on the slope slide, support element and the bottom of the case be the flange hole one -to -one offered of co -altitude not, and support element tightly supports on the ellipsoid conduit head bottom of the case inner wall around the flange hole in this support element corresponded through radial slide and slope slide compound movement, this support element's supporting disk, threaded hole is seted up along its axis direction to the supporting disk, and the supporting disk still matches and compresses tightly post, flange pressure disk and gland nut. This ellipsoid conduit head bottom of case ring flange installs equipment additional once adorns the card and accomplishes all ring flange welding, can guarantee the cooperation precision of flange hole and ring flange, and then guarantees the welding precision of the two.