type gasket material can be useful during an overhaul, but only the silicon
material specifically formulated for use as gaskets should be used, and it should
only be used where the parts will not have to be shifted after installation. The
silicon manufacturer's directions should be followed regarding the material's
Marking tags or marked bins.
As parts are removed from the unit, they
should be marked in some way to identify where they go and stored in a
manner so that they can be conveniently located during reassembly. For small
parts, such as nuts and bolts, storage bins labeled to show their contents are
helpful. For large or bulky parts, such as wicket gate grease lines, tags
describing what a part is and exactly where it goes are very useful. If the part
itself is marked, make sure the marking pen is permanent or use an engraver to
etch the part.
Welding rod or wire.
If the unit inspection indicated that substantial welding
repair is required, a supply of welding rod or wire should be obtained. Also, a
welding procedure for the required repairs should be written and distributed to
all personnel that will be involved in the welding.
Large rosebud or propane torches.
During removal of the thrust block, it is
important to heat it quickly so that it expands without transferring heat to the
generator shaft. Several large "weed burner" type propane torches or rosebud
oxyacetylene torches can be used for this purpose. As these torches are not
always dependable, it is a good idea to have at least two more than are
required to act as backups. These torches can also be helpful in breaking loose
frozen or severely corroded parts. Large rosebud torches use a great deal of
acetylene and sometimes require two acetylene bottles to be manifolded
together. The supplier of the torch should be able to provide information on
the acetylene requirements for a particular torch.
Various hydraulic jacks can be invaluable during an
overhaul. Large hollow-core jacks are very useful in lowering the turbine and
turbine shaft when breaking the coupling and in pulling the coupling bolts.
Hydraulic wedges and hydraulic rams of various sizes are helpful in breaking
loose stuck parts.
Hydraulic and pneumatic wrenches.
Hydraulic-operated wrenches can save
a great deal of time in removing bolts that would otherwise require the use of a
slugging wrench. Their primary use on hydrounits are breaking loose and
tightening the shaft coupling, bolts but on large units there may be a number of
other applications. Large pneumatic impact wrenches can also greatly speed