Turbine maintenance
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When removing the large cover of a steam turbine, how is the cat claw mechanism switched between upward and downward movement?
I’m referring to Hangqi back-pressure steam turbines. Before starting to remove the screws on the upper cover, it’s best to use jacks under the four claw-shaped components to lift them just enough so that they come into contact with the upper cylinder claws. It’s advisable to use a dial indicator for monitoring, so as to avoid over-lifting, which could lead to inaccurate measurement results later on. Loosen the locking nut, and then you can remove the large cover screws
For the shell at the cat’s paw section with an upper support structure, the marking is set at around 0.05; a value that is too high affects the measurement of the clearances between various parts of the rotor
Place the gauge on the rough claw of the upper cylinder, then lift the screw of the lower cylinder and move it upward slowly to ensure that the gauge reading remains unchanged