Applications of Magnetic Filtration

Orderil filtration in industrial and automotive machinery is essential to achieving optimum performance, reliability and longevity. Lubricant cleanliness is extremely important, and lubrication practitioners are supplied with many choices for filtering and controlling contamination, containing cedar filters, cleanable filters, strainers and centrifugal separators. This article discusses the mechanism of particle separation and reports that the numerous programs of magnetic filters and separators from the lubrication industry today. WPE Process Equipment manufacture high quality cross belt magnets in Australia. A concise guide to commercial filter products can also be presented.

From its source at the beneficiation of iron ores, the magnet has played an important role in the separation of ferrous solids from fluid streams. Even at the control of contamination from in-service lubricants and hydraulic fluids, magnetic separation and filter technologies have found a useful niche. Nowadays, there are some conventional and advanced products available on the marketplace which employ the use of magnets in a variety of configurations and geometry.

Purpose of Magnetic Filters
Car owners, automobile mechanics, equipment operators, maintenance technicians and reliability engineers know the importance of clean petroleum in achieving machine reliability. Tribologists and used oil analysts are also conscious that in some machines as far as 90 percent of particles suspended in the oil may be ferromagnetic (iron or steel particles). Typically, one or both lubricated sliding or rolling surfaces will have iron or steel metallurgy.

While it is correct that conventional mechanical filters can remove particles in exactly the identical size range as compressed seams, the vast majority of these filters are disposable and incur a cost for each gramme of particles eliminated. There are other penalties for using standard filtration, including energy/power consumption due to flow restriction brought on by the fine pore-size filter media. As pores become plugged with allergens, the restriction rises proportionally, inducing the power needed to filter the oil to escalate.

How do Magnetic Filters Work?
Though a lot of columns exist, many magnetic filters work by creating a magnetic area or loading zones that gather magnetic iron and steel particles. Magnets are geometrically arranged to form a magnetic field having a non-uniform flux density (flux density), can also be known as magnetic power) (Figure 1).

Particles are most efficiently separated whenever there is a strong magnetic gradient (rate of change of field strength with distance) away from low to high. In other words, the higher the magnetic gradient, the more powerful the attracting magnetic force acting on particles drawing them toward the loading zones. The strength of the magnetic gradient is determined by flux density, spacing and alignment of the magnets.

Various types of magnets can be utilised in these filters (see sidebar). Magnets used in some filters could have flux density (magnetic intensity) as large as 28,000 gausses. Compare this level to a normal refrigerator magnet of between 60 and 80 gausses. The greater the flux density, the greater the possible magnetic gradient and the magnetic force acting on nearby iron and metal particles.

Magnetic Slide. The most basic sort of magnetic filter is just a drain plug (Figure 2), in which a magnet in the shape of a disc or cylinder is attached to its interior surface (usually by adhesion). Periodically, the charismatic plug (mag-plug) has been removed and inspected for ferromagnetic particles, which are then wiped out of the plug.

Nowadays, such plugs are utilised in motor oil pans, gearboxes and occasionally in hydraulic reservoirs. One useful advantage of mag-plugs relates to examining the density of use particles found as a visual sign of the wear rate occurring within the machine on a fixed period of running period. The appearance of the iron filings on magnets has usually been described in review reports using terms like peach fuzz, whiskers or even Christmas trees. If a person normally sees purple fuzz, however on one event sees a Christmas tree rather, this would be a re portable condition requiring additional scrutiny and remediation. After all, abnormal wear produces abnormal levels of wear debris, leading to an abnormal collection of debris on magnetic plugs.

Rod Magnets. While magnetic plugs are inserted into the petroleum below the oil level (as an example, drain port), pole magnets can stretch down from reservoir tops (Figure 3), particular filter canisters (Figure 4) or within the centre tube of a typical filter element.

These collectors contain a set of rings or toroidal-shaped magnets assembled axially onto a metal rod. Between the magnets are spacers in which the magnetic gradient is the greatest, serving since the opening zone for the particles to gather. A conceptual illustration of a specific rod cylinder filter is displayed in Figure 1. When the rod is removed, the sheath or shroud could be slid from the magnet core to remove the collected debris. This debris can subsequently be prepared for microscopic evaluation to aid in checking machine state.

Flow-through Magnetic Debate.

But they do not interfere with the leak (clogging), or even hazard particles being washed off by viscous drag. One benefit of flow-through magnetic filters is that the massive amount of debris they hold before cleaning is necessary. The cleaning process typically involves removing the filter centre and blowing out the debris from involving the collection plates using an air purifier.

There are lots of providers of magnetic wraps, coils or similar devices intended for use on the outside of spin-on filter canisters (Fig 7a-c). Spin-on filters are utilised in the automotive industry but are also utilised in some low-pressure industrial applications. These wraps carry a magnetic field via the steel filter bowl (can) so as for ferromagnetic debris to be held closely against the internal surface of the bowl, allowing the filter to function normally while extending the service life. Unlike the traditional filter component, the charismatic filter wrap may be used again.

Factors Influencing Magnetic Separating Action
You’ll find a variety of magnets and also methods in which magnetic filters and separators can be configured within a product’s design. In actuality, there is significantly more …

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