Automatic oil filtration
Diesel engines are evolving in order to comply with stringent IMO emissions standards and to improve energy efficiency. As a result, modern engines require filtration adapted to new oil cleanliness standards, without impacting on pressure drop or space consumption. To lift this challenge, available filtering area needs to be increased in an optimized volume.
Compact and reliable, the Alfa Laval 290 filter is a self-cleaning disc-type automatic filter designed to protect sensitive engine parts. It provides full-flow filtration, particularly in lubricating oil and hydraulic control oil used for diesel engine installations onboard ships and in power plants.
Application
The Alfa Laval 290 filter is equipped with innovative Alfa Laval Atrium technology, which enables continuous automatic backflushing filters with virtually no pressure drop, even in the case of fine filtration. This innovative technology makes it possible to employ a large filtering area using less space than conventional automatic backflushing filters. It also improves backflushing efficiency due to enhanced distribution method that more effectively disperses the unfiltered oil to be cleaned.
Benefits
• Maximum engine protection, minimal engine wear
The Alfa Laval 290 filter provides fine filtration of particles
in oil down to 6 micron in size – with virtually no pressure drop. Its small footprint and large filtration surface area
ensure proper engine lubrication and minimal engine wear, thereby safeguarding engine operation.
• Compact and versatile
The Alfa Laval 290 filter offers up to 30% more filter surface area compared to conventional filters with the same footprint. Its footprint can be made even more compact when the filter is integrated directly into the engine.
• Easy to install, operate and maintain
No additional electrical power, air connection or dedicated tank is required. The Alfa Laval 290 filter is designed for
start-and-forget operation. Large filtering area reduces stress on the filter mesh, thereby prolonging the intervals between inspection. In addition, maintenance is quick and easy because there are few parts to disassemble.
• Reduced total cost of ownership
The Alfa Laval 290 filter is perfectly suited for improving total cost of ownership. Long-lasting wear parts reduce
spares consumption and maintenance costs are reduced to minimum. In addition, lubrication oil lifespan can be
increased by up to four times if installed with the optional. Alfa Laval Eliminator configuration. Diversion-type filters
also are an alternative to traditional cartridge-consuming backflush treatment devices.
Design
The Alfa Laval 290 filter is engineered for fine particle filtration of lubricating and hydraulic oil – with virtually no impact on pressure drop. It uses innovative Alfa Laval Atrium technology, which offers the best ratio between the filtering surface and the total footprint/volume of the filter available on the market.
The filters can be configured as a stand-alone filter, as an engine-mounted filter, or with by-pass valve and redundancy filter to meet virtually any filtration requirements. The Alfa Laval 290 filter can either be mounted to the engine or, when a more compact footprint is required, integrated into the engine. Standard, duplex and custom configurations are available.
Disc-shaped filter elements
The main components of the Alfa Laval 290 filter are patented disc-shaped Atrium filter elements (Figure 1) assembled into a disc stack. One filter element is comprised of two identical halves.
Ribbed aluminum filter frame
Each half includes a stack of filter media housed in an aluminum frame with ribbed sections (Figure 2). The filter
media has three layers: two outer layers to provide support and fatigue resistance and a filter layer in the middle.
Wide openings for filter inlet and outlet
The Alfa Laval Atrium technology also features a special arrangement of the filter mesh for wider openings at the
inlet and outlet than conventional filters. These enlarged openings smooth the passage of oil through the filter
(Figure 3, cut A–A)
Operating principle
The Alfa Laval 290 filter can be used for fine filtration of lubricating oil for four-stroke engines and for hydraulic oil
used for two-stroke engines.
For lubricating oil used for four-stroke engines
Unfiltered oil is transferred from the sump by means of a pump, through a heat exchanger, and on to the lubricating oil filter. Filtered oil then passes to the engine. Backflushed oil is recirculated to the tank. For highly efficient sludge removal, an optional sludge removal centrifuge can be installed on the backflush line. Oil cleaned in the centrifuge is then transferred to oil tank (Figure 4).
For hydraulic control oil used for two-stroke engines
Unfiltered oil is transferred from the sump by means of a pump, through a heat exchanger and, on to the main filter. Most of the filtered oil is used as engine lubricating oil; the remainder is sent for fine filtration in the hydraulic control oil filter and then to engine. Outlet flow is cleaned down to 6µm to protect the hydraulic control oil system, sensitive to fine pollution and low pressure. The backflush flow is filtered in the diversion chamber and directly re-circulated to the oil tank (Figure 5).
Optimized flow distribution system
Each filter element features a highly optimized flow distribution system (Figure 6). Ribs in the aluminum filter frame separate each element into 16 sealed, self-contained sections. The filter elements are stacked to meet the capacity requirements of the application and compressed together between two frames and by several springs. This guarantees tight seals between elements. A star-shaped shaft divided in 16 different columns is fitted to the stack center. Each column faces an individual section of the filter element, thereby forming 16 independent filtering columns.
A hydraulic motor driven by system pressure on top of the filter housing actuates a distributor. The distributor in contact with the star-shaped shaft rotates continuously to feed oil for filtration into one of the 16 columns. An indicator shows the rotation of the hydraulic motor and can also be actuated manually in case of emergency.
Continuous backflushing
The unfiltered oil entering the filter passes through a strainer. The distributor uniformly disperses the unfiltered oil into 15 of the 16 full-flow filtering columns. Solids collect on the filter medium and the filtered oil flows to the engine. Most of the filtered oil exits the filter element at the outlet. However, a small amount of the filtered oil, typically about 3%, passes through the sixteenth column in order to remove previously collected solids by backflushing the filter elements.
This oil is taken through a passage in the distributor, which rotates at continuous intervals to feed oil for filtration in 15 columns and to backflush in the sixteenth. In this way, all the columns are backflushed once per full rotation of the distributor. Backflushed oil is then re-circulated back to the oil tank for cleaning.
Highly efficient sludge removal
For highly efficient removal of solids in the backflushed oil, two optional treatment devices are available :
- For four-stroke engines, there is the optional Alfa Laval Eliminator, a high-efficiency centrifuge installed on the backflush line of the Alfa Laval 290 filter. The Alfa Laval Eliminator removes contaminants up to four times more efficiently than a traditional bypass centrifuge and increases the service life of lubrication oil by up to three to four times.
For two- and four-stroke engines, there is the optional integrated diversion chamber, which is an automatic
second-stage filter. Unlike cartridge backflush treatment systems, the Alfa Laval diversion chamber does not require frequent spare replacement, and no additional tank for treatment is required.
Options
- Single or duplex version.
- Sludge removal devices (Eliminator or diversion chamber).
- Custom housing.
- Counter-flanges included in delivery; connection size upon request.
- Pressure drop indicator, transmitter and gauges.
- Manual drain valve, automatic valve upon request.
Certifications
BV, LRS, DNV-GL, ABS, CCS, KR, NK, MRS, RINA. CE, ATEX upon request.
Technical data
The size, weight, flow rate and/or working condition of the Alfa Laval 290 filter are highly dependent upon the application. The information below provides an indication of technical data for the filter. Contact Alfa Laval with more detailed information about your filtration requirements so that we can provide you with a suitable solution for your filtration requirements.
| Engine type | Oil type | Filtration grade |
| Two-stroke | Hydraulic control oil | 6 µm |
| Main lubricating oil | 34, 45 µm | |
| Four-stroke | Lubricating oil | 25, 34, 45 µm |
| All | Fuel oil | 6,10, 25, 34, 45 µm |
| Filtration | Down to 6 µm abs |
| Normal filter outlet pressure | 0.8~6 bar (10~90 psi) |
| Min. filter outlet pressure | 0.8 bar (10 psi) |
| Max. filter inlet pressure | 7~12 bar (100~180 psi) |
| Test pressure | 24 bar (350 psi) |
| Max. viscosity | 130 cSt |
| Max. temperature | 70~100°C (150~210°F) |
| Alarm (pressure drop) | 0.8 bar (10 psi) |
| Backflushing flow | Down to 3% |
| Housing material | Cast iron |
| Filter medium material | Stainless steel |
The dimensions shown below are for a standard model. Depending on the surface area and number of filter elements required for your application, the size of housing will vary. Therefore, the overall size of the filter will be different.
| Dimensions (standard) | mm | in |
| Length | 520 | 20.5 |
| Width | 430 | 17 |
| Height | 680 | 26.5 |
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