What is the interference fit between the turbine set impeller and rotor?
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This post was last edited by llfffe on 2011-9-1 at 13:35. The company uses a back-pressure small steam turbine to drive the circulating water pump; its impeller is of the double-row impulse type, and it is fixed to the main shaft via thermal fitting, with splines being used to transmit torque. Axial positioning rings are also fitted thermally at both ends of the wheel disc. It has a power of 800 KW, with a steam inlet pressure of around 1.5 MPa and a temperature of 350°C; its rotation speed is approximately 4500 RPM. The main shaft seal is defective now, and the factory is planning to replace the main shaft. The nominal shaft diameter of the main shaft is 76.2 mm. What are the typical interference amounts between the main shaft of this small steam turbine and the impeller disk, as well as the positioning ring? Is there any senior colleague who has done shaft replacement in a factory? Are there any details that need to be paid attention to?
The amount of interference is generally fixed for turbine products; it varies from one manufacturer to another, but the differences are not significant. It is recommended that you consult the technical documentation related to the turbines you are using, as the information is available there. I look forward to answers from the experts on this chemical engineering forum
The manufacturer is located in the United States, so sending the shaft to them for replacement requires sending it to their factory in Taiwan, which takes nearly 3 months. I can’t wait. Some maintenance documents state that the excess amount is 0.0001 to 0.00016 of the diameter; I’m not sure if this is accurate. Has anyone experienced this before?
Reply to 1# llfffe: It’s best to contact the manufacturer. One thing to note is what type of seal is used for this turbine; some of the turbines made in the US have their sealing areas treated with spraying and grinding.