Section 6, Heat Exchangers (Oil/Air) - Gardner Denver L4-5C Original User Manual

SECTION 6
HEAT EXCHANGERS (OIL/AIR
OIL/AIR HEAT EXCHANGERS – The heat of compression absorbed by the oil injected into the
compressors (for cooling and lubrication) is ultimately rejected in a convenient medium such as air, for
these air-cooled cores. Proper operation of the heat exchangers is essential for the following processes:

The (L05) oil core maintains a compressor discharge temperature 100°F above the ambient
temperature while rejecting 5.1 kW of heat from the 2.9 gpm oil injection stream and operating at 110
psig discharge pressure. The standard (AEON4000) lubricating and cooling oil must be kept at a
normal operating temperature below 225F in order to preserve its longevity.

The (L05) air core maintains a package discharge temperature 17°F above ambient temperature
while rejecting 0.5 kW of heat from the 29 cfm air stream and operating at 110 psig discharge
pressure Be aware that this temperature differential (aka approach) may increase several degrees
due to environmental conditions such high air temperature and ambient humidity.
VENTILATION CONFIGURATION – Air-cooled cores (radiator-type) are provided as standard feature.
One (1) axial fan, located behind the fresh air inlet grille, delivers an air stream to: a) cool the exterior of
the main electric motor and b) meet the cooling demands of the air/oil combination heat exchanger on its
way out the package confines. The fan is mounted on a rear shaft of the main motor. In addition, an
open-weave, non-metallic mesh media is held in place over the fresh air inlet grill to pre clean the cooling
air stream.
Refer to Figure 6-1 for estimates of ventilation requirements. Please note that the air-cooled package
requires the combined total of the heat exchanger plus the enclosure ventilation flow rates (which include
motor ventilation and compressor intake). Furthermore, when package location makes it necessary to
duct fresh cooling air in/out, these ducts must be sized with a maximum (total) pressure loss of 0.1 inch
water gauge to avoid impacting the heat exchanger cooling air system. An external ventilation fan may
be required to properly evacuate hot air from the compressor room.
HEAT EXCHANGER MAINTENANCE - All the required hardware, mechanical and electrical connections
have been made at the Gardner Denver factory, thus the only regular maintenance required is to keep the
exterior core fins free from dirt and other airborne debris per the following procedure:
)
Minimum Cooling Air Flow Requirements
Model HP size
5 & 7.5
FIGURE 6-1 Air Flow Chart
13-25-629 v03
CFM
756
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