5
2.7
Procurement of equipment and supplies
Based on the inspection of the unit and on the discussions during the scheduling
meeting, a list of required materials, tools, and services should be made.
Specifications for materials and tools required for the overhaul should be prepared as
well as "Statements of Work" for contract services. If it is not certain whether
contract service will be required, the "Statement of Work" should be prepared so it
can quickly be issued once it is confirmed that it will be required.
meeting, a list of required materials, tools, and services should be made.
Specifications for materials and tools required for the overhaul should be prepared as
well as "Statements of Work" for contract services. If it is not certain whether
contract service will be required, the "Statement of Work" should be prepared so it
can quickly be issued once it is confirmed that it will be required.
Do not wait until the overhaul is in progress to order parts. Some parts, because
they are unusual or in short supply, may require several months lead time to procure.
they are unusual or in short supply, may require several months lead time to procure.
The following is a list of suggested materials and tools to have on hand
for a overhaul:
for a overhaul:
Wicket gate bushings, thrust washers, linkage bushings, and
shift ring
bearing pads.
At least one full set of wicket gate bushings, thrust washers,
linkage bushings, and shift ring bearing pads should be procured and onsite
prior to the overhaul. The wicket gate bushings should have an undersized
inner diameter to allow inplace line boring. If the spare bushings supplied with
the turbine do not have an undersized inner diameter, another set of bushings
should be ordered. A bearing bronze such as UNS C93200 should be
specified.
prior to the overhaul. The wicket gate bushings should have an undersized
inner diameter to allow inplace line boring. If the spare bushings supplied with
the turbine do not have an undersized inner diameter, another set of bushings
should be ordered. A bearing bronze such as UNS C93200 should be
specified.
There are several types of greaseless or self-lubricated bushings available from
various manufacturers for use in wicket gate applications. Each type has its
own application and installation requirements. Conduct extensive research
before switching to selflubricated bushings. Remember, if a wicket gate
bushing fails in service, in most cases the entire unit must be disassembled to
make repairs. Contact facilities that have installed the type of bushing being
considered to get an account of their experience. There have been failures of
some types of self-lubricated bushings attributed to contamination of sand or
other particles between the bushings and the journals. These contaminants are
flushed out by the periodic application of grease in grease-lubricated bushings.
Consider all factors, such as the cleanliness of the water and frequency of gate
operation, before making a choice.
various manufacturers for use in wicket gate applications. Each type has its
own application and installation requirements. Conduct extensive research
before switching to selflubricated bushings. Remember, if a wicket gate
bushing fails in service, in most cases the entire unit must be disassembled to
make repairs. Contact facilities that have installed the type of bushing being
considered to get an account of their experience. There have been failures of
some types of self-lubricated bushings attributed to contamination of sand or
other particles between the bushings and the journals. These contaminants are
flushed out by the periodic application of grease in grease-lubricated bushings.
Consider all factors, such as the cleanliness of the water and frequency of gate
operation, before making a choice.
Gasket and seals.
Based on drawing recommendations and on the unit
inspection, gasket materials, 0-rings, and other seals should be procured. The
seal materials should be compatible for the service for which they are intended.
Gaskets will be needed on flanged oil and water pipe connections, oil tubs,
generator air coolers, the packing box, and other similar applications. 0-ring
material is many times used as a seal on the headcover and oil tub covers. A
gasket cutting kit can speed up the making of special gaskets. Silicon caulking
seal materials should be compatible for the service for which they are intended.
Gaskets will be needed on flanged oil and water pipe connections, oil tubs,
generator air coolers, the packing box, and other similar applications. 0-ring
material is many times used as a seal on the headcover and oil tub covers. A
gasket cutting kit can speed up the making of special gaskets. Silicon caulking