ROTO Pump RMEA-561B9 0D 1D Progressive Cavity Screw Pump

ROTO Pump RMEA-561B9 0D 1D Progressive Cavity Single Screw Pump

The ROTO Pump RMEA-561B9 0D 1D is a positive displacement single screw progressive cavity (PC) pump engineered specifically for continuous, demanding fluid handling duties. Constructed with a single helical metal rotor rotating eccentrically within a resilient elastomer stator, this pump forms fixed, continuous progressing cavities that advance fluids axially from the suction port to the discharge face.

This progressive displacement mechanism ensures a non-turbulent, pulsation-free delivery stream directly proportional to rotational shaft speed. Built to thrive in harsh shipboard and heavy industrial environments, the RMEA-561B9 handles shear-sensitive liquids, viscous hydrocarbons, entrained solids, and abrasive slurries without degrading internal media or compromising volumetric efficiency.

Model Details

• Manufacturer / Brand: ROTO Pumps Ltd.
• Model Number / Designation: RMEA-561B9 0D 1D
• Manufacturer Part Number (MPN): RMEA-561B9-0D-1D
• Design Classification: Positive Displacement / Helical Rotor–Stator Single Screw Pump
• Staging Configuration: Single-Stage (1D Geometry / 6 bar nominal differential pressure class)
• Joint Mechanism: Heavy-duty, fluid-tight Cardan / Pin Universal Transmission Joint assembly protected by an elastomer boot sleeve

Technical Details:

Key Features

1. Laminar, Low-Shear Hydraulic Flow: Delivers a smooth, pulse-free stream that preserves fluid morphology, making it ideal for shear-sensitive media and oily water separation without chemical emulsification.
2. High Suction Lift & Self-Priming: Low Net Positive Suction Head Required (NPSHR) creates deep vacuum suction lift, enabling dependable self-priming from low-lying shipboard bilges and below-deck tanks.
3. Abrasion-Resistant Rotating Geometry: Precision-machined, hard-chrome-plated rotor resists abrasive wear when pumping silt, carbon soot, metal scale, and particulates in suspension.
4. Linear Volumetric Delivery: Flow rate remains strictly proportional to operating speed, allowing precise metering, transfer rates, and dosing control via Variable Frequency Drive (VFD) adjustment.
5. True Bi-Directional Pumping: Symmetrical internal components support reversible rotation, allowing simple tank filling, line clearing, or reverse draining depending on motor directional wiring.

Part Number & Brand Cross-References:

• Seepex®: BN 5-6L, MD 025-6L, MD 05-6L series
• Netzsch® NEMO®: NM038BY01L06B, NM045BY01L06B
• Allweiler®: SEBP 200, AEB 1E 200 series
• Mono Pumps®: C14, C15, Merlin / Compact C Series

Applications

• Marine Machinery Spaces: Marine engine room bilge water transfer, heavy fuel oil (HFO) separator sludge discharge, waste lube oil handling, and black/gray water marine sanitation device (MSD) transfers.
• Pollution Control & Treatment: Oily water separator (OWS) feeding without breaking down mechanical oil droplets into difficult chemical emulsions.
• Effluent & Sewage Processing: Municipal and industrial raw sewage, thickened primary/secondary sludge transfer, coagulant dosing, and lime slurry pumping.
• Petrochemical & Mining: Transfer of crude bottoms, settling pit slurries, spent drilling muds, lime milk, and hydrocarbon wastes containing grit or particulates.
• Paints, Coatings & Resins: Viscous polymers, printing inks, adhesives, and pigments where non-pulsing, continuous feed is required.

Frequently Asked Questions

What causes a progressive cavity pump to lose flow while the motor is running?

Flow loss is almost always caused by worn internal tolerances between the rotor and stator (stator slip), dry-run burn marks on the elastomer sleeve, or severe suction pipe cavitation caused by restricted strainers or excessive suction lift.

Can the ROTO RMEA-561B9 run in reverse direction?

Yes. The ROTO RMEA series is mechanically reversible. However, the fluid flow path reverses, turning the discharge port into the suction port and subjecting the drive shaft seal area to high delivery line pressure. Ensure the installed mechanical seal is rated for full system head before reversing operation.

How do I select the right stator elastomer for this pump?

Select Nitrile (NBR) for standard oily water, diesel, fuel oils, and general wastewater up to 90°C. Choose EPDM for hot water, mild acids, and caustic chemical dosing. Use Viton (FKM) for high-temperature applications (up to 150°C) or highly aggressive chemical and solvent mixtures.

Why is this progressive cavity pump preferred over a centrifugal pump for oily water separators?

Centrifugal impellers rotate at high speeds (1450–2900 RPM), creating high shear forces that mechanically emulsify oil and water into micro-droplets. Progressive cavity pumps run at low speeds with laminar displacement, moving the mixture without shearing it, which allows gravity plates and coalescers in the OWS to separate oil cleanly.

What maintenance is required during drydock or lay-up?

If the pump will remain idle for more than 30 days, flush all corrosive sludges and particulates from the casing using clean fresh water or light preserving oil. Relieve tension or back off the stator to prevent the elastomer from taking a permanent compression set along the rotor’s eccentric lobe lines.