Device for heating or cooling turbine casing joint bolts - uses hollow bodies fitted around bolt shanks to reduce thermal stresses

摘要

The device for heating or cooling turbine casing joint bolts, to minimise the temperature difference between them and the casing material and thus the thermal stresses, consists of closed hollow bodies (8) shaped to fit into the annual gap (7) between the bolt shank (6) and the casing flanges (1, 3; 2, 4). The bodies are at least partially filled with a fluid (9) which conducts heat well, through a sealable pipe (18) running through the washer (19) under the joint nut (20). The bodies' cylindrical sidewalls (10, 11) are of thin material and make good contact with casing and bolt shank respectively; increasing fluid press. with rising temp. improves that contact. Top (12), bottom (13) and end walls are curved inwards, further increasing the efficiency of the bodies and minimising the load on the joints.