# US 2019/0170152 A1 · Balancing system and method for turbomachine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170152 A1 - Document ID: US20190170152A1 - Status: Published application - Kind: A1 - Application number: 16/202,027 - Filed: 2018-11-27 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Nuovo Pignone Tecnologie Srl - Applicants: Nuovo Pignone Tecnologie Srl - Inventors: Luca SCARBOLO - Web page: https://patentgrep.com/patent/US20190170152A1 ## CPC - F04D 29/0516: {balancing pistons} - F01D 3/04: axial thrust being compensated by thrust-balancing dummy piston or the like - F04D 29/0416: {balancing pistons} - F04D 29/122: {especially adapted for elastic fluid pumps} - F05D 2220/32: in gas turbines - F05D 2240/10: Stators - F05D 2240/52: Axial thrust bearings - F05D 2240/55: Seals - F05D 2260/15: Load balancing - 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 ## Abstract The balancing system has a balancing body to be mounted on a rotor of a turbomachine and a sealing ring to be mounted on a stator of the turbomachine; the sealing ring is arranged around the balancing body so that the balancing body can rotate about a rotation axis, thus there is a clearance between the body and the ring; furthermore, there is an arrangement for changing an axial position of the sealing ring during operation of the turbomachine so that the clearance can be adjusted. The possibility of adjusting clearance during operation of the turbomachine, such balancing system provides a good balancing action with a small leakage and a small risk of mechanical interference at any time during operation of the turbomachine. ## Claims ### Claim 1 A balancing system for a turbomachine having a rotor and a stator, the balancing system comprising: a balancing body to be mounted on the rotor; a sealing ring to be mounted on the stator, wherein the sealing ring is arranged around at least a portion of the balancing body so the balancing body can rotate about a rotation axis extending longitudinally through the balancing body; the balancing system comprising further an adjuster configured to change an axial position of the sealing ring during operation of the turbomachine so that a clearance between the balancing body and the sealing ring can be adjusted during the operation of the turbomachine. ### Claim 2 (depends on 1) The balancing system of claim 1, wherein an inner surface of the sealing ring is frustum shape. ### Claim 3 (depends on 1) The balancing system of claim 1, wherein an outer surface of the portion of the balancing body is frustum shape. ### Claim 4 (depends on 1) The balancing system of claim 1, further comprising a control unit arranged to control the arrangement so to adjust the clearance. ### Claim 5 (depends on 4) The balancing system of claim 4, wherein the control unit is arranged to perform an open-loop control or a closed-loop control. ### Claim 6 (depends on 1) The balancing system of claim 1, wherein the arrangement comprises an actuator being electric-type or a magnetic-type or a hydraulic-type or a pneumatic-type. ### Claim 7 (depends on 1) The balancing system of claim 1, wherein the balancing body has a first surface and a second surface, wherein the balancing body is arranged so that a fluid at a first pressure exerts a force on the first surface and pushes the balancing body axially in a first sense and a fluid at a second pressure exerts a force on the second surface and pushes the balancing body axially in a second sense, the second sense being opposite to the first sense. ### Claim 8 (depends on 1) A turbomachine comprising a balancing system according to claim 1, wherein the balancing body is fixed to a shaft of the turbomachine. ### Claim 9 A method of balancing axial thrust in a turbomachine comprising a rotor and a stator, wherein the turbomachine comprises a balancing body and a sealing ring, wherein the balancing body is fixed to a shaft of the rotor of the turbomachine, wherein the sealing ring is fixed to the stator of the turbomachine, wherein the sealing ring is arranged around at least a portion of the balancing body so that the balancing body can rotate about a rotation axis, wherein the method comprises: A) starting the turbomachine, B) pressurizing a fluid at a first pressure on a first side of the balancing body, C) pressurizing a fluid at a second pressure on a second side of the balancing body, and afterwards during operation of the turbomachine D) changing an axial position of the sealing ring thereby adjusting a clearance between the balancing body and the sealing ring. ### Claim 10 (depends on 9) The method of claim 9, wherein the step D is repeated during operation of the turbomachine. ### Claim 11 (depends on 9) The method of claim 9, wherein the step D is carried out by means of one of the following actuators: an electric actuator, a magnetic actuator, a hydraulic actuator, a pneumatic actuator. ### Claim 12 (depends on 9) The method of claim 9, wherein the step D is carried out under manual control or automatic control, in particular open-loop control or closed-loop control. ### Claim 13 (depends on 12) The method of claim 12, wherein the automatic control comprises first measuring one or more of the following parameters: inlet pressure of the turbomachine, outlet pressure of the turbomachine, inlet temperature of the turbomachine, outlet temperature of the turbomachine, rotation speed of the turbomachine, temperature of a zone of the turbomachine, temperature of a zone of the sealing ring, temperature of a zone of the balancing body, fluid flow in a clearance between the balancing body and the sealing ring, size of a clearance between the balancing body and the sealing ring, axial thrust on a bearing of the turbomachine; and then calculating an axial position based on one or more of the parameters. ### Claim 14 (depends on 9) The method of claim 9, wherein the axial position of the sealing ring is reset to an initial position just before shutting down or tripping the turbomachine.