Page 72 - Introduction to Marine Engineering
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Steam turbines and gearing 59
Multi fork
T-slot
Fir tree
Figure 3,6 Blade fastening
through a gate or entrance slot and sliding it into position. Successive
blades are fitted in turn and the gate finally closed with a packing piece
which is pinned into place. Shrouding is then fitted over tenons on the
upper edge of the blades. Alternatively, lacing wires may be passed
through and brazed to all the blades.
End thrust
In a reaction turbine a considerable axial thrust is developed. The
closeness of moving parts in a high-speed turbine does not permit any
axial movement to take place: the axial force or end thrust must
therefore be balanced out.
Dummy
cylinder
Dummy
piston
Balancing
force
Balance pipe
Figure 3.7 Dummy piston balance arrangement
