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13–10–612 Page 1
SECTION 1
GENERAL INFORMATION
FIGURE 1–1 – COMPRESSION CYCLE
COMPRESSOR – The Gardner Denver
R
Electra–
Saver
R
compressor is a single–stage, positive dis-
placement rotary machine using meshing helical rotors
to effect compression. The input drive shaft and helical
drive gear are supported in the gear case by high ca-
pacity tapered roller bearings. The drive gear meshes
with a driven gear mounted on the main rotor shaft to
drive the rotors. Both rotors are supported between
large capacity anti–friction bearings located outside the
compression chamber. Single–width cylindrical roller
bearings are used at the inlet end of the rotors. Early
models used two (2) heavy–duty, single–row, angular
contact ball bearings at the discharge end to locate
each rotor axially and carry all thrust loads; later mod-
els use tapered roller bearings in this location.
COMPRESSION PRINCIPLE (FIGURE 1–1) – Com-
pression is accomplished by the main and secondary
rotors synchronously meshing in a one–piece cylinder.
The main rotor has four (4) helical lobes 90
_
apart. The
secondary rotor has five (5) matching helical grooves
72
_
apart to allow meshing with main rotor lobes.
The air inlet port is located on top of the compressor
near the center. The discharge port is near the bottom
at the opposite end of the compressor cylinder.
FIGURE 1–1 is an inverted view to show inlet and dis-
charge ports. The compression cycle begins as rotors
unmesh at the inlet port and air is drawn into the cavity
between the main rotor lobes and secondary rotor
grooves (A). When rotors pass the inlet port cutoff, air
is trapped in the interlobe cavity and flows axially with
the meshing rotors (B). As meshing continues, more of
the main rotor lobe enters the secondary rotor groove,
normal volume is reduced and pressure increases. Oil
is injected into the cylinder to remove the heat of com-
pression and seal internal clearances. Volume reduc-
tion and pressure increase continues until the air/oil
mixture trapped in the interlobe cavity by the rotors
passes the discharge port and is released to the oil res-
ervoir (C). Each rotor cavity follows the same ”fill–com-
press–discharge” cycle in rapid succession to produce
a discharge air flow that is continuous, smooth, and
shock–free.
AIR FLOW (FIGURE 1–2 and FIGURE 1–3, Page 2)
– Air enters the air filter and passes through the inlet un-
loader valve to the compressor. After compression, the
air/oil mixture passes into the oil reservoir where most
of the entrained oil is removed by velocity change and
impingement and drops back into the reservoir. The air
and remaining oil then passes through the oil separa-
tor; the separated oil is returned to the system through
tubing connecting the separator and compressor. The
air passes through the reservoir discharge manifold,
discharge check valve, minimum pressure valve and
the customer furnished unit shutoff globe valve to the
plant air lines.
LUBRICATION, COOLING, AND SEALING – Oil is
forced by air pressure from the oil reservoir through the
oil cooler, thermal control (thermostatic mixing) valve
and oil filter and discharges into the compressor main
oil gallery. A portion of the oil is directed through internal
passages to the bearings, gears, and shaft oil seal. The
balance of the oil is injected directly into the compres-
sion chamber to remove the heat of compression, seal
internal clearances, and lubricate the rotors.
TURN VALVE – The turn valve is a rotary helical valve
located on the discharge side of the cylinder toward the
inlet end. The valve opens and closes ports in the cylin-
der which communicates with the inlet passage. This
varies the compressor rotor volume to match the de-
mand for air, thus reducing the part–load power re-
quirement.
Summary of Contents for ELECTRA-SAVER EAU PD - 200 HP
Page 13: ...13 10 612 Page 3 FIGURE 1 4 STARTER BOX FIGURE 1 5 PACKAGE CONTROLLER AND STARTERS...
Page 16: ...13 10 612 Page 6 DECALS 206EAQ077 212EAQ077 218EAQ077 211EAQ077 207EAQ077...
Page 17: ...13 10 612 Page 7 DECALS 216EAQ077 217EAQ077 222EAQ077 221EAQ077 208EAQ077...
Page 40: ...13 10 612 Page 30 FIGURE 4 8 CONTROL SCHEMATIC COMPRESSOR AT FULL LOAD 214ECM797 Ref Drawing...
Page 42: ...13 10 612 Page 32 FIGURE 4 10 WIRING DIAGRAM 212EAP546 Ref Drawing...
Page 43: ...13 10 612 Page 33 FIGURE 4 11 AUTO SENTRY ES CONTROLLER DISPLAY...
Page 45: ...13 10 612 Page 35 FIGURE 5 1 FLOW DIAGRAM AIR OIL SYSTEM 215EAU797 Ref Drawing...
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