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13-11-608 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 four (4) helical lobes 60
°
apart. The secondary
rotor has six (6) matching helical grooves 60
°
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 1-4, page 4 and
Figure 1-5
, page 5) - 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 1-4, page 4 and
Figure 1-5
), page 5 - 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
- Lubricating oil flows from the oil reservoir into the oil pump, where it is delivered, under pressure,
into the oil filter, and subsequently, injected onto the bearings and gears. The oil drains, by gravity, from the bottom
of the gear and discharge housings back into the oil reservoir.
Summary of Contents for PUREAIR EWD99E
Page 7: ...13 11 608 Page 2 Figure 1 2 PACKAGE ILLUSTRATION AIR COOLED 302EWD797 A Ref Drawing...
Page 8: ...13 11 608 Page 3 Figure 1 3 PACKAGE ILLUSTRATION WATER COOLED 303EWD797 A Ref Drawing...
Page 9: ...13 11 608 Page 4 Figure 1 4 WATER COOLED SCHEMATIC 300EWD797 D Ref Drawing...
Page 10: ...13 11 608 Page 5 Figure 1 5 AIR COOLED SCHEMATIC 301EWD797 D Ref Drawing...
Page 30: ...13 11 608 Page 25 Figure 4 2 FLOW CHART FOR SETUP PROGRAMMING 300EWC1255 Ref Drawing...
Page 44: ...13 11 608 Page 39 301EWD546 B Ref Drawing Page 2 of 2...
Page 46: ...13 11 608 Page 41 302EWD546 B Ref Drawing Page 2 of 2...
Page 48: ...13 11 608 Page 43 303EWD546 B Ref Drawing Page 2 of 2...