maximum ambient temperature of 40 degrees C 100 degrees F. Heat exchanger
tubes and fins shall be copper or copper alloy. Working pressure shall
exceed the oil pump working pressure. The heat exchanger shall withstand a
test pressure of 150 percent of the design pressure held for a period of 4
hours during which time the heat exchanger shall be checked for leakage.
Any leakage shall be cause for rejection. The oil-to-air heat exchanger
system shall include a fan, motor, and controls for maintaining the
specified oil temperature.]
2.8.6
Cooling Water Control Valve
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NOTE: Delete if an oil-to-air heat exchanger is
used.
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A thermo-mechanical control valve shall be provided to adjust the flow rate
of water through the heat exchanger to maintain a minimum oil temperature
of 50 degrees C 120 degrees F in the housing sump.
2.8.7
Piping and Tubing
Oil lines up to 50 mm 2 inches o.d. shall be seamless steel tubing with 37
degree flare or flareless fittings. Where pipe sizes of 50 mm 2 inches and
over are required, steel pipe with welded fittings shall be used. Water
piping shall be copper or copper alloy with brazed or 95-5 soldered joints.
All piping, tubing, and fittings shall conform to ASME B31.1. Vibration
isolating tubing and piping supports shall be used. Oil tubing or ports
shall be kept within the gear case where feasible. Dissimilar metals shall
be electrically isolated to prevent corrosion.
2.8.8
Oil Heater
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NOTE: In regions where the temperature during flood
season is rarely below 10 degrees C (50 degrees F),
consideration may be given to omission of the oil
heater. However, omission of the oil heater is
generally not recommended because it results in poor
oil circulation at startup and it is impractical to
size the filter to avoid a bypass condition at
temperatures below 20 to 25 degrees C (70 to 80
degrees F). Accumulated contaminants can be passed
at unacceptable concentrations during a bypass
condition. The oil heater should be used since it
will help ensure adequate oil flow during unit
startup. Caking of the oil on the heater is
prevented by using a low watt density heater, 9300
watts per square meter (6 watts per square inch).
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A thermostatically operated oil heater shall be installed to maintain the
oil at a temperature of 25 degrees C 80 degrees F. The heater shall be
sized based on a minimum ambient temperature of [minus 10 degrees C 15
degrees F] [_____]. The heater shall be capable of being shut off if the
unit is to be out of service for an extended period. The heater shall have
a watt density no greater than 9300 watts per square meter 6 W/inch squared.
SECTION 15005A
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