Atlas Copco 1616834880 Air End for GA and GX Series Screw Compressors

Role of the Air End in a Screw Compressor

The 1616834880 air end is the compression heart of GA and GX series rotary screw compressors. Inside the cast iron housing, a matched pair of helical rotors turns in synchronization. The male rotor receives shaft power from the drive motor through a belt or direct coupling. The male rotor then drives the female rotor through the meshing action of their interlocking lobes. Atmospheric air enters the inlet port at one end of the housing. As the rotors turn, the trapped air volume decreases continuously along the rotor profile. Pressure builds until the compressed air-oil mixture discharges at the working pressure of the compressor system.

This air end operates on the oil-injected compression principle. Pressurized oil enters the compression chamber near the inlet side. The oil film seals the running clearance between the rotor lobes. This sealing action maintains high volumetric efficiency by preventing compressed air from leaking back to the inlet zone. The oil also absorbs compression heat and lubricates the support bearings at both ends of the rotor shafts.

Power Range and Application Profile

Atlas Copco engineers the 1616834880 for the 3.7 kW to 7.5 kW power class. This places it in the small-capacity industrial segment. Typical end-user applications include automated production line pneumatic controls, automotive repair shop air supply, CNC machining center clamping and tool blow-off, and food and beverage auxiliary packaging systems. The air end supports both belt drive and direct drive configurations. Facilities select the drive type based on motor speed, available space, and maintenance preferences for the specific compressor installation.

SAP Rotor Profile and Compression Efficiency

The 1616834880 air end incorporates the proprietary SAP (Standard Atlas Copco Profile) rotor design. This profile features an optimized sealing line geometry. During rotation, the rotor lobes maintain a controlled running clearance against each other and the housing bore. The SAP profile shapes the contact line between the male and female rotors to minimize the physical leakage triangle at the discharge end. A smaller leakage triangle means less compressed air recirculates from the high-pressure discharge zone back to the low-pressure inlet zone. This directly improves volumetric efficiency and reduces specific power consumption during continuous-duty operation.

The 4/6 rotor arrangement pairs a four-lobe male rotor with a six-lobe female rotor. This geometric combination balances internal gas forces across the rotor length. The even distribution of pressure loads prevents rotor deflection under full-load conditions. Rotor deformation would increase the running clearance and degrade compression performance over time. The 4/6 configuration also produces lower torque ripple at the drive shaft compared to alternative lobe counts. Smoother torque delivery reduces vibration transmitted to the compressor frame and connected pipework.

Oil Injection and Internal Lubrication Circuit

Oil enters the compression chamber through dedicated injection ports near the inlet side of the housing. Internal oil galleries cast into the housing deliver pressurized lubricant to each bearing location. Radial bearings at the inlet and discharge ends of both rotors handle the gas pressure loads. An axial thrust bearing absorbs the net thrust force from the pressure gradient along the rotor length. High-precision clearances between the oil seals and air seals prevent lubricant migration into the compression chamber. A dedicated drainage path vents any oil that approaches the air seal boundary. This isolation design ensures the compressed air output remains free of lubricant contamination while maintaining full bearing lubrication.

Recognizing Air End Wear Indicators

Under normal industrial operating conditions with regular lubricant changes, the 1616834880 air end delivers an expected service life of 20,000 to 40,000 hours before requiring its first bearing overhaul. Several indicators signal that the air end approaches the end of its service interval:

• Gradual capacity loss: The compressor takes longer to reach system pressure or fails to maintain rated airflow. Internal rotor clearances have increased over thousands of operating hours. A flow measurement at the service valve quantifies the capacity decline. The loss typically progresses gradually rather than appearing suddenly.
• Elevated discharge temperature: The air-oil mixture exits the air end at a temperature higher than the historical operating baseline under similar ambient and load conditions. Increased internal recirculation of hot compressed air through worn clearances raises the discharge temperature.
• Increased oil carryover: The downstream air-oil separator element loads faster than normal. Worn rotor clearances allow more oil to bypass the normal compression path. Oil consumption rises above the routine replenishment rate.
• Unusual vibration or noise: Deteriorating bearings produce elevated vibration levels. A bearing condition monitoring program with regular vibration measurements detects bearing degradation before a catastrophic failure occurs.

Rebuild versus Replacement Decision

In most service scenarios, the 1616834880 air end can be rebuilt using a complete overhaul kit. The rebuild process replaces the high-precision bearings, shaft seals, and clearance shims. A successful rebuild restores the factory tolerances and extends operational life at a lower cost than purchasing a new element. Full element replacement becomes necessary only when the housing casting shows physical cracks, the rotor surfaces exhibit severe scoring beyond re-machining limits, or the element has suffered total mechanical seizure. Oil analysis results guide the rebuild versus replacement decision. Rising bearing wear metal concentrations signal deteriorating bearing surfaces before vibration levels become critical.

If you need other Atlas Copco air compressor air ends, we provide more models in the table below or you can submit your requirements to us directly.