# US 7,743,497 B2 · Method of providing non-uniform stator vane spacing in a compressor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,743,497 B2 - Document ID: US7743497B2 - Status: Granted - Kind: B2 - Application number: 11/244,372 - Filed: 2005-10-06 - Published: 2007-04-12 - Granted: 2010-06-29 - Earliest claimed: 2005-10-06 - Assignees: General Electric Company - Inventors: James C. Gautreau; Stephen P. Wassynger - Web page: https://patentgrep.com/patent/US7743497B2 ## CPC - F04D 29/667: {by influencing the flow pattern, e.g. suppression of turbulence} - F01D 9/041: {using blades (F01D5/148 takes precedence)} - F04D 29/542: {Bladed diffusers (fixing blades to stators F01D9/042)} - F04D 29/666: {by means of rotor construction or layout, e.g. unequal distribution of blades or vanes} - F05D 2230/80: Repairing, retrofitting or upgrading methods - F05D 2260/961: by mistuning rotor blades or stator vanes with irregular interblade spacing, airfoil shape - Y10T 29/49236: Fluid pump or compressor making - Y10T 29/49238: Repairing, converting, servicing or salvaging - Y10T 29/49318: Repairing or disassembling - Y10T 29/49321: Assembling individual fluid flow interacting members, e.g., blades, vanes, buckets, on rotary support member - Y10T 29/49716: Converting - Y10T 29/4973: Replacing of defective part - Y10T 29/49732: by attaching repair preform, e.g., remaking, restoring, or patching - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Stator blade counts of an upper compressor casing for adjacent stages S0 and S1 are changed in the field to provide additional stator vanes and hence an increased vane count. Particularly, the upper casing half of the compressor is removed from the lower casing half. The original stator vanes on opposite axial sides of the first stage buckets are removed from the upper casing half and replaced by an additional sets of stator vanes providing a non-uniform vane spacing as between the upper and lower halves of the compressor as well as between axially adjacent stages S0 and S1. The unequal vane counts reduce the vibratory response of the rotating blades between stages S0 and S1. ## Claims ### Claim 1 A method of retrofitting a compressor comprising the steps of: (a) removing an upper half of the compressor casing in situ to open the compressor; (b) removing a first set of stator vanes of an array thereof having a first blade count from the removed upper half of the compressor casing; (c) in place of the removed first set of stator vanes, installing in the removed upper half of the compressor casing a second set of stator vanes with a second vane count different than the vane count of said first set of stator vanes, while maintaining without change, all original stator vanes in a lower half of the compressor casing; and (d) closing the compressor by securing the upper half of the compressor casing with the second set of stator vanes to the lower half of the compressor casing. ### Claim 2 (depends on 1) A method according to claim 1 wherein step (b) includes removing from the removed upper half of the compressor casing a third set of stator vanes of another array thereof and on an opposite axial side of the rotating compressor blading from said one array of stator vanes; and, in place of the removed third set of stator vanes, installing in the removed upper half of the compressor casing a fourth set of stator vanes with a blade count different than the blade count of the third set of stator vanes. ### Claim 3 (depends on 1) A method according to claim 1 wherein step (c) includes installing the second set of stator vanes in the removed upper half of the compressor casing with a blade count greater than the blade count of the stator vanes of a corresponding lower compressor casing half of the same compressor stage. ### Claim 4 (depends on 3) A method according to claim 3 wherein the second set of stator vanes has twenty-six vanes and the corresponding lower half of stator vanes has twenty-three vanes. ### Claim 5 (depends on 1) A method according to claim 1 wherein step (b) includes removing from the removed upper half of the compressor casing a third set of stator vanes of another array thereof and on an opposite axial side of the rotating compressor blading from said one array of stator vanes; and, in place of the removed third set of stator vanes, installing in the removed upper half of the compressor casing a fourth set of stator vanes with a blade count greater than the blade count of the stator vanes of a corresponding lower compressor casing half of the same compressor stage. ### Claim 6 (depends on 5) A method according to claim 5 wherein the fourth set of vanes has twenty-four vanes and the corresponding lower half of stator vanes has twenty-three vanes. ### Claim 7 (depends on 1) A method according to claim 1 wherein steps (a)-(d) are performed to reduce the vibratory response of one set of rotating compressor buckets to aerodynamic excitation pulses generated by at least one array of stator vanes adjacent to the one set of rotating compressor buckets.