MIL-HDBK-1003/7
Oil Purifiers. Where a separate turbine oil reservoir and oil coolers are
5.7.3
used, a continuous bypass purification system with a minimum flow rate per hour equal to
10 percent of the turbine oil capacity shall be used. Refer to ASME Standard LOS-1M,
ASTM-ASME-NEMA Recommended Practices for the Cleaning, Flushing, and Purification of
Steam and Gas Turbine Lubricating Systems. The purification system shall be either one
of the following types.
Centrifuge With Bypass Particle Size Filter. See Figure 20 for arrangement of
5.7.3.1
equipment. Because of the additives contained in turbine oils, careful selection of the
purification equipment is required to avoid the possibility of additive removal by use
of certain types of purification equipment such as clay filters or heat and vacuum
units. Both centrifuge and particle size filters are suitable for turbine oil
purification. Particle filters are generally sized for not less than 5 microns to avoid
removal of silicone foam inhibitors if present in the turbine oil used. The centrifuge
is used periodically for water removal from the turbine oil. The particle
filter, usually of the cellulose cartridge type, is used continuously except during
times the centrifuge is used.
Multistage Oil Conditioner. See Figure 21 for arrangement of equipment. The
5.7.3.2
typical multistage conditioner consists of three stages: a precipitation compartment
where gross free water is removed by detention time and smaller droplets are coalesced
on hydrophobic screens, a gravity filtration compartment containing a number of cloth-
covered filter elements, and a storage compartment which contains a polishing filter
consisting of multiple cellulose cartridge filter elements. The circulating pump
receives oil from the storage compartment and pumps the oil through the polishing filter
and back to the turbine oil reservoir. The storage compartment must be sized to contain
the flowback oil quantity contained in the turbine generator bearings and oil supply
piping. The oil conditioner in this type of purification system operates continuously.
Lubricating Oil Storage Tanks. As a minimum, provide one storage tank and one
5.7.4
oil transfer pump. The storage tank capacity should be equal to, or greater than the
largest turbine oil reservoir. The transfer pump is used to transfer oil between the
turbine oil reservoir and the storage tank. The single tank can be used to receive oil
from, or return oil to the turbine oil reservoir. Usually a separate portable oil
filter press is used for oil purification of used oil held in the storage tank. Two
storage tanks can be provided when separate tanks are desired for separate storage of
clean and used oil. This latter arrangement can also be satisfied by use of a two-
compartment single tank. Only one set of storage tanks and associated transfer pump is
needed per plant. However, it may be necessary to provide an additional oil transfer
pump by each turbine oil reservoir, depending on plant arrangement.
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