ApplicationPurification or clarification (optional) of mineral oils usedin marine installations and power stations:• Distillates• Marine Diesel Oils MDO up to 13 cSt at 40°C• Lubricating oils for trunk diesel engines operating on

distillates and light MDO• Lubricating oils for steam and gas turbines• Lubricating and hydraulic oils for hydroelectric

power stations

ConceptThe MMB series of solids-retaining separators is available in two models, the MMB 304 and MMB 305.

Each MMB separation system comprises:• An MMB separator• Ancillary equipment consisting of connections and

valve assembly

Optional equipment• Independent oil feed pump• Oil heating system, steam or electric• Water seal alarm MAWA-40

Features and benefitsThe unique features of the system are:• Compact, robust design• Internal paring disc for discharge of clean oil• Large sludge space• Belt-driven

The major benefits are:• Easy to install.

Requires limited space.• Pressurised discharge of clean oil.

No need for downstream pump.• Fewer service manhours.

Larger sludge space extends operating period betweenmanual cleaning.

• Lower maintenance and spare parts costs.

MMB 305 solids-retaining separator.

MMBSolids-retaining centrifugal separators

Water seal alarm MAWA-40.

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System working principleSeparation takes place in a solids-retaining, also known as a solid-wall,bowl that can be arranged for purifica-tion or clarification (optional). In bothcases the contaminated oil is fed to theseparator by a feed pump through theoil inlet and is separated by centrifugalforce into its various phases. The heavi-est phase, sludge, is forced to anddeposited at the periphery of the bowl.Separated sludge is collected in thespace at the periphery of the bowl andremoved periodically by hand using thestainless steel sludge basket. The cleanoil is continuously discharged by thebuilt-in paring disc pump. Water leavesthe bowl via an open outlet.

When operated in purifier mode, agravity disc must be fitted to obtain thecorrect interface position (the boundarybetween the separated oil and thewater seal) in the separator bowl. In theoptional clarifier mode, a clarifier disc isfitted instead of a gravity disc.

A MAWA-40 water seal alarm is avail-able as optional equipment to monitorthe pressure in the clean oil outlet. Thecontrol unit will shut off the oil feed tothe separator in case a pressure drop is detected and give an audible andvisible alarm.

InstallationThe MMB separation system isdesigned for installation as a completesystem. The schematic layout in thefigure below shows a typical installationof an MMB separator. Contaminatedfuel or oil is supplied by the feed pumpfrom the oil tank to the separator bowlfor continuous cleaning.

After separation, the cleaned oil is dis-charged by a built-in paring disc pump.

The complete system includes MAWAwater seal alarm, starter, heater, valves,piping and other essential ancillaryequipment.

Purifier-Clarifier.

1. Oil inlet 4. Sludge basket2. Oil outlet 5. Sludge3. Water outlet 6. Sealing water inlet

1. MAWA-40 water seal alarm unit2. Constant flow valve3. Separator4. Pressure switch5. Pressure gauge

6. Regulating valve7. Three-way valve8. Thermometer9. Temperature sensor

10. Preheater

11. Flow switch12. Oil feed pump13. Strainer14. Solenoid valve, air15. Flexible hoses

16. Control unit for heater17. Starter for separator

and pump

Schematic installation layout of an MMB separation system.

Freshwater

Sludge andwater outlet

Compressedair

Oil outlet

Oilinlet

Oil recir-culation

Standard design MMB 304/305The MMB 304/305 series are solids-retaining separators that are identicalin concept, with different throughputcapacities.

Each separator model comprises aframe, power transmission and bowlassembly.

The lower frame houses the flat-beltpower transmission unit connected toa vertical drive shaft with friction clutchto the vertical bowl spindle.

The bowl is fixed on top of the spindleinside the space formed by the upperpart of the frame and the frame hood.

The frame hood also contains the oilinlet and outlet and the sealing waterinlet. The separated water is dischargedby gravity through an outlet pipemounted on the frame.

Basic equipment• MMB separator• Sealing water inlet with hose nipple,

non-return valve and constant flowvalve with vacuum breaker

• Set of gravity discs• Set of resilient mountings• Stainless steel sludge basket• Flexible hoses for: oil, water outlet

and drain, and sealing water inlet• Intermediate service kit

Additional equipment required for operation• Electric motor and starter• Oil feed pump and starter• Set of tools

Optional equipment• MAWA-40 water seal alarm unit• Pressure switch kit• Three-way valve kit• Preheater• Clarifier disc• Major service kit

Technical data in brief

MMB 304 MMB 305Input voltage supply: 220/230, 380/400,

415, 440 V AC (50/60 Hz)Power consumption at max. rec. flow 1.4 kW 2.3 kWfor gas oil:

Shipping data

Dimensions (mm)MMB 304 MMB 305

A 910 935B 795 795C 465 465

Weight (kg)Type of equipment Net GrossSeparator MMB 304– without motor 185 235– with motor 201 251Separator MMB 305– without motor 190 240– with motor 218 268

Technical documentationComplete information and documen-tation accompany each separatorsystem.

After Sales supportAlfa Laval’s Preventive MaintenanceProgram is available for the MMB 300series. Alfa Laval service engineers areavailable to assist you with all types ofmaintenance and repair, and to helpyou train your personnel.

The use of genuine Alfa Laval spareparts reduces down-time and repaircosts. Spare parts kits can be orderedfrom Alfa Laval Marine Service Centersand stocked as single units.

Intermediate service kits for routinebowl maintenance and major servicekits for bowl overhaul are available.

All service kits include detailed serviceinstructions.

EMD00096EN 0702 Alfa Laval reserves the right to change specifications without prior notification.

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How to contact Alfa LavalUp-to-date Alfa Laval contact details for all countries are always available onour website at www.alfalaval.com

Throughput capacitiesThe blue bars indicate range from minimum economical throughput on detergenttype lubricating oil for trunk diesel engines to a maximum recommended through-put on distillate fuel (1.5–6 cSt/40°C). Detailed information on throughput capacitiesis provided on separate data sheets for each model.

For more detailed information see the separate data sheet of each model.

MAB 206

MMB 305

MMB 304

MAB 104

MAB 103

MAB 102

2 000 4 000 10 000l/h

0 6 000 8 000