IMO ACF 080-3N4C5 Screw Pump

IMO ACF 080-3N4C5 Screw Pump — Industrial & Marine Technical Profile

The IMO ACF 080-3N4C5 is a three-screw pump engineered specifically for non-pulsating, continuous transfer and circulation of lubricating oils, hydraulic fluids, and fuel oils. Built on IMO’s proven axial-flow screw geometry, the ACF generation pumps feature one centrally driven power rotor intermeshing with two balanced idle rotors. The pumped medium forms a hydraulic cushion that isolates the rotors, eliminating metal-to-metal radial contact and ensuring minimal internal shear, ultra-low operating noise levels, and long service intervals.

Designed predominantly for marine propulsion systems, power plant turbomachinery, and large-scale hydraulic skids, the 080-frame pump delivers dependable volumetric output against medium backpressures, even when handling wide viscosity swings.

Technical Details:

Features

1. Pulsation-Free Axial Flow: Hydraulic balance across the intermeshing triple-screw cluster eliminates fluid cavitation pulsations and dynamic line shock.
2. Integral Safety Relief Valve: Internal differential relief valve routes bypass volume back into the suction cavity, safeguarding against downstream blockages.
3. Internally Lubricated Bearings: Internal ball bearing configuration bathed directly in the operating fluid, removing requirements for external grease points.
4. Low Noise & Vibration Footprint: Engineered rotor geometry dampens acoustic resonance (typically ≤73 dB(A) at 1450 rpm / 7 bar).
5. High Volumetric Efficiency Across Viscosity Bands: Maintains consistent flow rates across diesel, distillate, heavy fuel oil (HFO), and high-viscosity lubricants (up to 5,000 cSt).

Compatibility

• Main Marine Engine Lubrication: Main engine crankcase and bearing oil supply, crosshead lubrication, and turbocharger oil feed.
• Pre-Lubrication & Auxiliary Circulation: Pre-lube skids for 4-stroke marine diesel and dual-fuel auxiliary engines (e.g., Wärtsilä, MAN Energy Solutions, HiMSEN).
• Bunkering & Fuel Transfer: Transfer of Low Sulfur Heavy Fuel Oil (LSHFO), Marine Gas Oil (MGO), and marine diesel between double bottom, settling, and service tanks.
• Power Plant Turbomachinery: Jacking oil, governor oil, and bearing oil circulation systems in gas and steam turbine skids.
• Industrial Hydraulics & Cooling: Low-pressure booster loops, press chamber pre-fill systems, and transformer oil insulation loops.

Direct Engine & Machinery Cross-References

• MAN B&W: 32/40, 48/60, and 51/60 auxiliary and main engine lubrication modules.
• Wärtsilä: 20, 32, and 46 series lube oil booster/transfer modules.
• Hyundai Heavy Industries (HiMSEN): H17/28, H21/32 auxiliary engine lube oil circuits.
• Standard Interchangeable Replacements: IMO UCF 080 series (ANSI flanged counterpart), IMO ACG 080, IMO D4 080 frame pumps.

Frequently Asked Questions

What does the model code IMO ACF 080-3N4C5 signify?

The code denotes an IMO low-pressure ACF series screw pump featuring an 80 mm power rotor diameter (080), Normal lead rotor geometry (N), generation designator (4 or 5), and specific seal/relief valve configuration (C5) with an integrated mechanical seal and internal safety relief valve.

Can the IMO ACF 080 pump run in both rotational directions?

Standard ACF pumps are built for unidirectional clockwise (CW) rotation when looking directly onto the pump drive shaft. Counter-clockwise (CCW) builds can be supplied upon special factory request. Reverse rotation is only permitted for brief periods (under 2 minutes at <3 bar backpressure) to drain piping lines.

What is the difference between an IMO ACF and an IMO UCF pump?

The core pumping mechanics and rotor geometries of the ACF and UCF series are functionally identical. The primary difference lies in the connection ports: the ACF series utilizes DIN-standard flange dimensions, whereas the UCF series uses ANSI flanged ports.

What maintenance kits are required for servicing the ACF 080?

Routine service utilizes the IMO G050 kit (replacement mechanical seal) or G053 minor kit (mechanical seal plus all case O-rings, gaskets, and internal ball bearings). For a complete overhaul involving damaged rotor tracks, a G054 major kit or replacement G012 rotor set is required.

What causes low discharge pressure in an IMO screw pump?

Common causes include entrained air/suction line leaks, excessively worn rotor bores or casing liners from abrasive contamination, an improperly seated or debris-fouled internal safety relief valve, or low fluid viscosity outside the design window.