ALF - Alfa Laval Filter

ALF - Alfa Laval FilterFiltration for cooling systems using low-quality waterClosed-loop cooling systems where the secondary circuit iscooled using inexpensive water from the sea, lakes or riversare widely used in many industries.Such installations require large quantities of clean coolingwater. With an ever-diminishing supply of high-quality coolingwater, the need for cost-effective solutions to eliminateclogging, fouling and corrosion becomes ever-greater. In acooling system incorporating a heat exchanger and an AlfaLaval Filter, even polluted or corrosive water can be used tocool the most sensitive process equipment.The Alfa Laval Filter (ALF) operates as an integral part ofa cooling system to remove debris that can foul and clogplate heat exchangers, tubular condensers, cooling towerspray nozzles or any similar equipment. In spite of effectivescreening at the water intake, mussels, seaweed and otherforms of marine life can settle on the heat transfer surfaces.Conditions are ideal for the growth of these forms of life andthey multiply rapidly as a result. This causes less effectiveheat transfer and possibly the complete breakdown of heatexchangers or other equipment.If these kinds of blockages are severe, measures such aspesticides or chlorination are often no longer sufficient. Insome cases these cannot be used because they are prohibited by environmental legislation.This is where Alfa Laval Filter technology comes in. It protectsa wide range of sensitive equipment from clogging andfouling, and prevents blockages in the cooling water system.An Alfa Laval Filter removes debris and marine life, and isautomatically backflushed at regular intervals to keep it clean.Several thousand ALF filters are in operation in coolingsystems around the world. Characterized by its effectiveness,fully automatic operation and low maintenance requirements,ALF filters have become popular in many different applications including power plants, processing industries, districtheating, sea vessels and comfort cooling systems.

Operation and designThe Alfa Laval Filter is a pressure filter with an automaticflushing arrangement. The design features a pressure vesselcasing made of stainless steel (ALF-S), fibreglass reinforcedpolyester (ALF-P) or rubber-lined carbon steel (ALF-R andALF-B). Along with other wetted parts, the internal cylindricalfilter basket is usually made of stainless steel, super stainlesssteel (SMO) or titanium.ALF-B is a standardized model aimed at tasks where specialoptions are not required. Just as the other models it offersreliable protection for your heat exchangers and fully automatic operation (backflushing).Apart from the standard range of ALF filters, we can supplyspecial versions that can handle pressures up to 16 bar andtemperatures up to 100 C (212 F). We also provide N and Ustamp certificates.The filter system is available with connections ranging from100 mm/4” to 800 mm/32” and is designed to be placed directlyin the pipe system. ALF filters can be installed in almost anyposition, horizontally or vertically thanks to the flexible nozzleorientation and because the automatic regeneration process isrun by the inlet pressure.The inlet is placed at one end and the main outlet at a 90 angle, making it suitable for installation on any 90 pipe bendclose to the equipment to be protected. The inspection/service opening is placed on the opposite side of the inlet,providing easy service access with no need to remove thepipe connection.Backflushing is carried out automatically at regular intervalswithout interrupting the filtering process. The flushing valveand a flow diverter valve are controlled by a PLC in thecontrol panel, which can be installed close to the filter.The filter is divided into two sections by the flow divertervalve, the inlet section and the outlet section. A flushing valvefor discharging the debris is located at the end of the outletsection.Extending performancewith the Alfa Laval 360 Service PortfolioOur extensive service offer ensures top performancethroughout the lifetime of your Alfa Laval equipment. Excellentavailability of parts and the commitment and expertise of ourteam bring you peace of mind.Start-up Installation Installation Supervision CommissioningSupport Troubleshooting Telephone support TrainingMaintenance Service kits and spareparts Preventive maintenance RepairsImprovements, monitoring Equipment upgrades Replacement and retrofitWe can also create a Performance Agreement – a customized service agreement for you that includes any or all of theabove services.InstallationALF units can be installed upstream of heat exchangers withshut-off valves placed upstream of the filter and downstreamof the heat exchanger. This enables flexible servicing if manyunits are installed in parallel – for instance in a duty/standbyinstallation or when installed on a bypass pipe, allowing thefilter to be taken out of service separately.Depending on pipe dimensions, flow rate and permissiblepressure drop, one ALF filter can be installed to protectseveral heat exchangers. The filter(s) should preferably bemounted close to the heat exchanger(s) in order to minimizethe risk of biological growth in the pipe system connectingthe components.We recommend connecting the flushing outlet to the heatexchanger outlet when possible, and returning the debristo the natural water source. It is important that the filter isinstalled downstream of the feed pump(s), operating as apressure filter.Standard control panel withPLC for one filter. Alternativeconfigurations are availablefor controlling multiple filters.Options for remote control orhigh protection classes, suchas ATEX, are also available.

Flushing valveNormal operationDuring normal operation, liquid passesthrough the inlet into the filter basket. Theflow diverter valve is open and the flushingvalve closed. The liquid passes through thefilter basket prior to being discharged at themain outlet.NORMAL OPERATIONInlet sectionOutlet sectionRegenerationALF units can be cleaned either automatically,using a timer, at predetermined intervals, ormanually by pushing a button on the controlpanel. An optional differential pressure controlsystem is available as a back-up and for monitoring the filter status.1. Primary flushingThe flushing valve opens, reducing the pressure drop and increasing velocity and totalflow through the filter. Any debris sticking tothe filter basket is dislodged and flushed outthrough the flushing valve. The velocity ofthe liquid is sufficient to remove any debrisembedded in the inlet section of the basket.2. Secondary flushing (backflushing)The flow diverter valve closes while the flushingvalve remains open. The flow is diverted andforced to pass through the filter basket inthe inlet section. The majority of the liquid isdischarged through the main outlet, but thepressure in the filter draws part of the flow fromthe exterior to the interior of the outlet section.This provides a backflushing effect in thissection of the filter. Any dislodged remnantsare discharged through the flushing valve.REGENERATION – primary flushingFlow diverter valveREGENERATION – secondary flushing (backflushing)

DimensionsAALF-RA B CALF 20R 325720 1,230ALF 30R 425950 1,610ALF 40R 496 1,150 1,961ALF 50R 600 1,400 2,380ALF 60R 700 1,650 2,605ALF 80R 905 2,080 3,720BALF-R with filter casing made of rubber-linedcarbon steelCALF-SAA B CALF 10S 175 450740ALF 15S 250 595975ALF 20S 300 720 1,180ALF 30S 400 950 1,610BALF-S with filter casing made of stainless steelCAALF-PA B CALF 10P 250530890ALF 15P 300685 1,150ALF 20P 350840 1,400ALF 30P 520 1,130 1,820ALF 40P 570 1,150 2,110BCALF-BA B CALF 10B 146411696ALF 15B 210567948ALF 20B 242649 1,107ALF 30B 340852 1,454AALF-P with filter casing made of fibreglassreinforced polyesterALF-B with filter casing made of rubber-linedcarbon steelBC

Pressure drop for ALF FiltersPressure dropbar 30 40 50 60 80 10050 70 100220440200300 400 50010008020202010Recommended capacity 252000 3000500020030050010002000 3000500010000200008801320220044008800 13200 2200044000880001086541Kg/sm3/hUSgpmFlow rateFig. 3 Recommended pressure drop and capacity rangeTechnical dataConnectionsEN 1092.1/PN10ANSI B16.5/B16.47, B series, # 150OperationPneumatic, electricMesh sizePerforated plate design (Ø hole)Wedge wire design (slot size)MaterialsFilter body (ALF-R)Filter body (ALF-S)Filter body (ALF-P)Filter body (ALF-B)Internal parts (wetted)Internal parts (wetted)Internal parts (wetted)Design codeEN13445 / ASME VIII, div.1/div.2Design codeADM N1Design codeEN13445Design pressure10 bar (g) / 150 psiDesign temperature60 C / 149 FControl panelPLC-basedRequired service areaX x Y m (Z x W ft)PEE00007EN 1610How to contact Alfa LavalUp-to-date Alfa Laval contact details for allcountries are always available on our websiteat ctuator controlled valves1.0-1.5-2.0-2.5 mm0.1-0.3-0.5-1.0 mmRubber-lined carbon steel EN P265 GH/ASTM A516 Gr60Stainless steel EN 1.4404 ASTM 316LFibreglass reinforced polyester (GRP/FRP)Rubber-lined carbon steel P355GH / ASTM A516 Gr 70Stainless steel EN 1.4404 ASTM 316LSuper stainless steel, EN 1.4547 / ASTM S31254 (SMO)Titanium, EN 3.7025 / ASTM B265 Grade 2ALF-R / ALF-SALF-PALF-BAlternatives on requestAlternatives on requestPower supply: 1 110-230 V, 50-60 HzAlfa Laval reserves the right to change specifications without prior notification.

cooling system incorporating a heat exchanger and an Alfa Laval Filter, even polluted or corrosive water can be used to cool the most sensitive process equipment. The Alfa Laval Filter (ALF) operates as an integral part of a cooling system to remove debris that can foul and clog plate he