Atlas Copco 1616725681 Air End Screw Compressor

Atlas Copco P/N: 1616725681 Rotary Screw Compressor Air End

The Atlas Copco P/N 1616725681 (engineering code OIS O-01 / C168 Head) is a single-stage, oil injected, asymmetric rotary screw compression element for heavy-duty industrial and maritime compressed air systems. This compression head is based on Atlas Copco’s proprietary male and female rotor profiles for positive displacement air compression with optimum internal volumetric efficiency.

The assembly has a cast iron casing with dual helical rotors supported by heavy duty taper roller and cylindrical roller bearings to take up radial and axial thrust stresses. The rotor bore is positioned to provide oil injection ports for sealing, rotor lubrication and to drain heat from the compression process.

Model Details

• Primary OEM MPN: 1616725681
• Formatted OEM MPN: 1616 7256 81
• Hyphenated OEM MPN: 1616-7256-81
• Factory Designation: Element OIS O-01 / C168 Air End Head
• Service Element Part Number: 1616725691 / 1616-7256-91

Compatible Atlas Copco Air Compressor Models

This air end assembly is factory-installed on or compatible with the following stationary and mobile screw air compressors:

Atlas Copco GA Series (Oil-Injected Stationary Compressors):

• GA90 / GA90+
• GA110 / GA110+
• GA132 / GA132+
• GA160 / GA160+
• GA180VSD (Variable Speed Drive)
• GA200 / GA200W
• GA250 / GA250W

Atlas Copco Portable/Mobile Compressor Series:

• XAH1066
• XAH2250

Key Features

1. Precision Asymmetric Rotor Geometry: Engineered with Atlas Copco’s proprietary rotor profile to minimize internal blow-by gas leakage and lower specific energy consumption (SER) per CFM.
2. Heavy-Duty Bearing Arrangement: Features dual angular-contact taper bearings at the high-pressure discharge end to handle continuous axial thrust load under high discharge pressure.
3. Integrated Oil-Injection Cooling Channels: Internal passages distribute oil directly into the compression pocket to absorb heat of compression, preventing thermal distortion.
4. Ductile Cast-Iron Casing: Heavy-wall housing absorbs mechanical vibrations and operational pressure spikes, ensuring low acoustic emission and resistance to structural fatigue.
5. Pre-Set Internal Clearances: Factory-set axial and radial rotor clearances eliminate the need for field shimming during replacement installation.

Industrial & Marine Applications

• Marine Main & Auxiliary Air Systems: Continuous 30-bar starting air priming and 7–10 bar service air distribution on commercial vessels, tankers, and offshore platforms.
• Heavy Industrial Manufacturing: Reliable source of compressed air for automated assembly plants, pneumatic tools, and central plant air distribution network.
• Mining & Heavy Earthmoving Equipment: Engine-driven mobile compressor plants operating under high dust and extreme ambient temperature environments.
• Petrochemical & Processing Plants: Continuous compressed air feed for nitrogen generators, pneumatic valve actuators, and process instrumentation.
• Shipyard & Blasting Operations: Continuous high-volume air supply for sandblasting setups and heavy paint spraying operations.

Chief Engineer’s Field Inspection Note:

When changing out an air end on a marine vessel or isolated shore plant, never rely solely on alignment pins. Thermal growth on a 132kW to 250kW drive train requires exacting radial and axial laser alignment between the gearbox drive coupling and the input shaft of the 1616725681 element. A mismatch greater than 0.05 mm will ruin the input drive shaft bearings within 500 operating hours.

Frequently Asked Questions

What is the function of the Atlas Copco 1616725681 air end?

The Atlas Copco 1616725681 air end (also known as the OIS O-01 element) is the core positive displacement compression module in a rotary screw air compressor. It takes ambient air, compresses it between two high-precision intermeshing helical rotors, and delivers high-pressure air mixed with cooling oil to the oil separator vessel.

Which compressor models use the 1616725681 air end element?

This element is primarily fitted to Atlas Copco GA series industrial air compressors, including GA90, GA110, GA132, GA160, GA180VSD, GA200, and GA250 models, as well as mobile compressor units like the XAH1066 and XAH2250.

What is the difference between part numbers 1616725681 and 1616725691?

Part number 1616725681 refers to the original standard assembly factory part number, while 1616725691 is the designated service exchange or replacement stage part number provided by Atlas Copco for field replacement and maintenance programs.

Why is pre-lubrication necessary before starting a new 1616725681 air end?

Starting a new or reconditioned air end dry can cause metallic contact between the rotor lobes and damage the carbon-steel drive shaft seal within seconds. Pouring oil into the suction housing guarantees immediate fluid film lubrication upon initial shaft rotation.

How do I know if my 1616725681 air end needs to be replaced or overhauled?

Key indicators include excessive vibration levels exceeding ISO 10816 limits, unusual mechanical whining or grinding noises from the bearing housings, elevated operating temperatures due to internal rotor contact, or a noticeable decline in free air delivery (FAD) output pressure.