IMO ACG 052N7 NTBP 100 Triple Screw Pump

IMO ACG 052N7 NTBP 100 Triple Screw Pump

The IMO ACG 052N7 NTBP 100 STD is a positive displacement three-screw pump engineered specifically for demanding maritime fuel handling, circulation, and lubrication duties. Built on CIRCOR IMO’s Generation 7 design platform, this self-priming unit delivers low-shear, pulsation-free volumetric discharge across broad viscosity and temperature gradients.

Configured with the “NTBP” standard execution, this unit integrates a high-integrity nodular cast iron casing (EN-GJS-400 / GGG-40), a high-temperature Silicon Carbide-on-Silicon Carbide (SiC/SiC) mechanical seal with Viton (FKM) elastomers (Fuel Line specification), and an internal adjustable pressure relief valve calibrated for full operating envelope safety (up to 16 bar). The 2019-manufactured series retains direct mounting compliance for IEC frame motors via standard bell housings and flexible jaw couplings.

Model Details:

• Model Series: ACG – Industrial/Marine Three-Screw Pump (Low-Pressure Series)
• Rotor Diameter: 052 – 52 mm Power Rotor Outer Diameter
• Rotor Lead: N – Normal Pitch / Normal Lead Rotor Profile
• Design Generation: 7 – Revision Generation 7 (Standard modular platform)
• Body Material: N – Nodular Cast Iron / Ductile Iron (EN-GJS-400-15)
• Shaft Seal Design: T – Heavy-duty Fuel Line mechanical seal: Silicon Carbide vs. Silicon Carbide faces, Viton (FKM) elastomers
• Bearing Construction: B – External permanently grease-lubricated deep-groove ball bearing
• Valve Execution: P – Integral internal safety relief valve adjustable up to maximum working pressure (16 bar)
• Execution Code: 100 STD – Clockwise (CW) rotation viewed facing shaft end, standard DIN/ISO counter-flange interface
• Manufacturer Part Number (MPN): ACG 052N7 NTBP 100 / ACG052N7-NTBP

Key Features

1. Pulsation-Free Hydraulic Geometry: Hydraulically balanced three-screw configuration (one power rotor intermeshing with two idler rotors) eliminates fluid pulsing, vibration, and fluid shear, protecting inline viscosity meters and burner nozzles.
2. High-Temperature SiC/SiC Fuel Line Seal: The “T” seal configuration resists abrasive cat fines and thermal cracking in heavy fuel oil (HFO/VLSFO) circuits up to 155°C (311°F) without external cooling loops.
3. Rugged Nodular Iron Casing: Ductile iron housing provides robust pressure containment up to 16 bar differential and superior impact resistance compared to standard grey cast iron, meeting unified IACS marine requirements.
4. Integral Full-Flow Relief Valve: Spring-loaded internal bypass valve protects both the pump element and driver against system overpressure or accidental discharge line closure.
5. External Grease-Lubricated Bearing: Ball bearing assembly isolated from process fluids prevents premature bearing failure caused by fuel contaminants, sulfur compounds, or poor lubricity distillates (MGO/MDO).

Technical Details:

Applications

• Fuel Oil Booster & Feeder Circuits: Supplying continuous high-pressure Heavy Fuel Oil (HFO), Low Sulfur Heavy Fuel Oil (LSHFO), and Very Low Sulfur Fuel Oil (VLSFO) to main engine fuel injection systems.
• Marine Gas Oil (MGO/MDO) Service: Handling low-viscosity distillates where the hard SiC/SiC seal faces prevent boundary-layer friction damage.
• Centrifugal Separator Feed Pumps: Supplying unpurified fuel and lube oil settling tanks into primary purifier loops at constant non-turbulent flow rates.
• Thermal Oil & Heat Transfer Circulation: Secondary circulation loops operating at temperatures up to 155°C (311°F).
• Engine Lub-Oil Priming & Auxiliary Circulation: High-reliability lube oil circulation for main propulsion turbines, reduction gears, and marine turbochargers.

Frequently Asked Questions

What does “NTBP” mean on an IMO ACG pump?

“NTBP” specifies the construction configuration: N indicates a Nodular Cast Iron casing; T designates a Fuel Line mechanical seal with Silicon Carbide vs. Silicon Carbide faces and Viton elastomers rated up to 155°C; B refers to an external grease-lubricated ball bearing; and P denotes an integral full-pressure adjustable safety relief valve.

What is the primary difference between IMO NVBP and NTBP pumps?

The difference lies in the mechanical seal face materials and operating temperature ratings. NVBP uses a Carbon/Silicon Carbide seal designed for lubricating and hydraulic oils up to 90°C. NTBP uses hard-wearing Silicon Carbide/Silicon Carbide seal faces designed for heavy fuels, light distillates, and aggressive or contaminated liquids up to 155°C.

Can the IMO ACG 052N7 NTBP run in reverse?

The pump is engineered to run in one direction only (standard Clockwise facing the shaft end). Running in reverse is permitted only for short intervals (less than 3 minutes) strictly for line evacuation or stripping, provided backpressure does not exceed 3 bar. Long reverse runs will starve internal balancing pistons and cause seal failure.

Is this pump compatible with ultra-low sulfur marine gas oil (ULS-MGO)?

Yes. While light distillates have poor lubricity and lower viscosity, the Silicon Carbide seal faces and hydraulically balanced rotors perform reliably down to 1.4 cSt. However, when handling viscosities below 2.0 cSt, the maximum continuous differential pressure must be derated according to IMO technical tables to prevent accelerated liner slip.

Can I install this pump vertically?

Yes. The IMO ACG series can be mounted either horizontally or vertically using standard angle brackets and connecting bellhousings. Note that when mounted vertically, bearing re-greasing intervals must be reduced by 50% relative to standard horizontal service schedules.