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13-11-607 Page 1
SECTION 1
GENERAL INFORMATION
Figure 1-1 – TYPICAL COMPRESSION CYCLE
COMPRESSOR
- The Gardner Denver Rotary Screw compressor is a single stage, positive displacement rotary
machine using meshing helical rotors to effect compression. Both rotors are supported between high capacity roller
bearings located outside the compression chamber. Single width cylindrical roller bearings are used at the inlet end
of the rotors to carry part of the radial loads. Angular contact ball bearings at the discharge end locate each rotor
axially and carry all thrust loads and the remainder of the radial loads.
COMPRESSION PRINCIPLE
(Figure 1-1) - Compression is accomplished by the main and secondary rotors
synchronously meshing in a one-piece cylinder. The main rotor has six (6) helical lobes 60
°
apart. The secondary
rotor has eight (8) matching helical grooves 45
°
apart to allow meshing with main rotor lobes.
The air inlet port is located on top of the compressor cylinder near the drive shaft end. The discharge port is at the
bottom on the opposite end of the compressor cylinder. Figure 1-1 is an inverted view to show inlet and discharge
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 the 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 grove, normal volume is reduced and pressure increases.
Water is injected into the cylinder to remove the heat of compression and seal internal clearances. Volume reduction
and pressure increase continues until the air/water mixture trapped in the interlobe cavity by the rotors passes the
discharge port and is released to the air/water reservoir (C). Each rotor cavity follows the same “fill-compress-
discharge” cycle in rapid succession to produce a discharge air flow that is continuous, smooth, and shock free.
AIR FLOW IN THE COMPRESSOR SYSTEM
(Figure 1-3, page 3) - Air enters the air filter and passes through the
inlet unloader valve to the compressor. After compression, the air/water mixture flows to the separator/reservoir tank
where most of the water is removed by velocity change and impingement. The air flows to the aftercooler, then to the
moisture separator where the water that has condensed out is removed from the air stream. The air then flows
through the package discharge check valve and to the plant air system.
WATER SYSTEM
(Figure 1-3, page 3) - Water is forced by air pressure from the separator/reservoir tank through
the heat exchanger, the system water filter and into the water injection manifold where the water is distributed to the
compression chamber injection ports. The water removes the heat of compression and seals internal clearances.
Seals minimize water leakage out of the compression chamber.
LUBRICATION
- Oil in the oil reservoir at the discharge end of the airend lubricates the discharge end bearings.
Grease fittings are located at the inlet end of the airend for periodic lubrication of the inlet end bearings.
Summary of Contents for PUREAIR EWC99C
Page 7: ...13 11 607 Page 2 Figure 1 2 PACKAGE ILLUSTRATION 307EWC797 B Ref Drawing...
Page 8: ...13 11 607 Page 3 Figure 1 3 AIR WATER SCHEMATIC 308EWC797 F Ref Drawing...
Page 25: ...13 11 607 Page 20 Figure 4 2 FLOW CHART FOR SETUP PROGRAMMING 300EWC1255 Ref Drawing...
Page 38: ...13 11 607 Page 33 Figure 4 4 WIRING DIAGRAM FULL VOLTAGE 305EWC546 B Ref Drawing Page 1 of 2...
Page 39: ...13 11 607 Page 34 305EWC546 B Ref Drawing Page 2 of 2...
Page 41: ...13 11 607 Page 36 306EWC546 B Ref Drawing Page 2 of 2...