Apparatus for raising the dynamic performance limit of steam flow and gas flow turbines and compressors

An apparatus for use in connection with reduction of vibration exciting forces to effect raising of dynamic performance limit of flow in a rotary machine of the turbine and compressor type having a leakage flow, the combination of:

• rotatable means, stationary wall means in the form of a ring surrounding said rotatable means in radially spaced relationship thereto so as to define therewith an annular clearance, non-contacting sealing means arranged in said clearance and supported by said ring while forming a labyrinth seal including throttling elements, housing means surrounding said ring in radially spaced relationship so as to form therewith an annular gap, said labyrinth seal including an active section and at least one throttling element the improvement comprising that said ring provided with passage means extending from said clearance to said annular gap and being located ahead of said active section of said seal and past at least one of said throttling elements, the dimensions of said passage means and of at least one of said throttling elements being so selected that the major portion of the leakage flow is passed directly into said clearance through said passage means which provide less resistance to flow.