Netzsch LN48/80-S0-6L Double Screw Pump

Netzsch LN48/80-S0-6L Double Screw Pump

The Netzsch LN48/80-S0-6L is a sturdy, internally bearing double screw positive displacement pump for continuous, low-pulsation fluid transfer in high-stress maritime and industrial applications. This pump employs an intermeshing twin-rotor design contained in a precision machined pressure casing, using the hydrodynamic qualities of the pushed medium to lubricate its internal bushings and screw surfaces. The design provides a hydraulic equilibrium condition to reduce axial loads and extend the structural life under continuous duty cycles.

Model Details:

• Manufacturer: Netzsch Pumps & Systems
• Model Designation: LN48/80-S0-6L
• Manufacturer Part Number (MPN): LN48/80-S0-6L
• Pump Series: NOTOS 2NS (Twin Screw Series) / LN Foot-Mounted Frame
• Condition: New Unused Surplus

Technical Specifications: Netzsch LN48/80-S0-6L 

Part Number Cross-References

• Netzsch Series: NOTOS 2NS 48 Frame
• Marine Yard Interchange Codes: 2NS-LN-048 / LN4880S06L
• Industry Alternates: Equivalent footprints match specific configurations of IMO ACE/ACG series or Allweiler SPF/TRD series twin-screw systems within identical displacement ranges.

Primemover Drive Compatibility

• Electric Motor Mounts: Directly couples via f
• exible spacer couplings to standard IEC Frame motors (e.g., 160M, 180M/L, 200L frames) or NEMA equivalents.
• Control Systems: Fully compatible with Variable Frequency Drives (VFD) for precision capacity management across broad RPM ranges without slipping or loss of hydrostatic lift.

Key Features

1. Hydrodynamic Radial Balance: Integrated internal product-lubricated bushings absorb radial forces entirely, preventing metal-to-metal contact between the screw profiles and pump casing.
2. Pulsation-Free Medium Displacement: The precision pitch helix configuration translates fluids linearly along the screw axis, preventing cavitation, fluid shearing, and foaming.
3. High Net Positive Suction Head (NPSHr) Performance: The optimized internal chamber profile delivers self-priming capabilities and high vacuum suction, ensuring reliable operation under tough suction lifts.
4. Ruggedized Marine Cast-Iron Housing: Built with an EN-GJL-250 gray cast-iron casing paired with nitrided alloy steel screws to ensure high resistance to thermal elongation and wear.
5. Foot-Mounted Footprint Optimization: The compact, inline horizontal footprint allows for rigid structural mounting directly onto vessel tank-top plates or industrial skids.

Applications

• Marine Main Engine Lubrication: Circulating system oils throughout large two-stroke and four-stroke marine propulsion engines.
• Heavy Fuel Oil (HFO) Transfer & Booster Services: Pumping high-viscosity residual fuels from storage bottoms to day tanks and fuel conditioning modules.
• Industrial Hydraulic Power Units: Serving as low-noise, high-pressure charging pumps for large-scale hydraulic systems using industrial mineral oils.
• Refinery and Tank Terminal Stripping: High-efficiency fluid extraction of lubricating oils, blending components, and base chemical feedstocks from storage tanks.
• Power Plant Fuel Feeding: Steady feeding of light/heavy fuel oils into high-output thermal boilers and combustion turbine systems.

Expert Engineering Insight

Internal Bearing Gating Notice: Because the LN48/80-S0-6L uses internal, product-lubricated bushings, the pumped fluid serves as the single source of hydrodynamic lubrication for the internal rotating surfaces.

CRITICAL RULE: Never allow this pump to run dry. Running the pump dry will starve the internal bushings of fluid, leading to thermal expansion and eventual galling of the nitrided screw surfaces against the cast iron body. Always verify that the suction lines are fully primed before starting the system.

Guide for Fleet Installation & Maintenance:

1. Suction Strainer Filtration: Ensure a duplex suction strainer rated at a minimum of 250 microns is installed upstream. While the pump can handle minor, non-abrasive particulates, large weld slag or scale from shipboard piping can score the precision screw clearances, causing internal slip and reducing discharge pressure.
2. Cold Start Viscosity Protection: When using the pump to transfer heavy residual oils (like HFO or high-viscosity lubes) during cold restarts, make sure to bring the oil up to its proper storage temperature first. Pumping fluid that exceeds the 9,000 cSt limit places extreme mechanical load on the driving keyways and coupling elements.
3. Mechanical Seal Inspection: During standard 4,000-hour vessel preventive maintenance checks, inspect the leakage drainage port beneath the mechanical seal house. A steady drip of more than 5 drops per hour indicates that the internal Viton/FKM secondary seals or primary seal faces are wearing down and need replacement.

Frequently Asked Questions

What does the “LN” code signify in the Netzsch model number?

The LN code indicates the pump’s mechanical structural layout. It denotes a foot-mounted, horizontal configuration featuring internal product-lubricated hydrodynamic bearings. This design is optimized for space-limited shipboard engine rooms and industrial fluid skids.

Can the Netzsch LN48/80-S0-6L pump handle chemical or water-contaminated oils?

Yes, provided the overall lubricity of the medium is maintained and the fluid remains within the 6 to 9,000 cSt viscosity envelope. However, if the fluid has a very high water content, the hydrodynamic film thickness on the internal bushings can drop, which will accelerate wear over time.

How do you regulate the output flow on this positive displacement pump?

Because screw pumps are positive displacement machines, they displace a fixed volume per revolution. To control the flow rate efficiently, you should change the rotational speed of the driver using a Variable Frequency Drive (VFD), rather than throttling the discharge valve. Throttling the discharge valve will trip the system’s external safety pressure relief valve.

Is the internal mechanical seal field-replaceable?

Yes. The shaft sealing assembly uses standard cartridge configurations or DIN-standard mechanical components. It can be serviced through the front bearing cover plate without requiring you to disconnect the main suction and discharge piping from the pump body.