An oil filter is a filter designed to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil. Their chief use is in internal-combustion engines for motor vehicles (both on- and off-road ), powered aircraft, railway locomotives, ships and boats, and static engines such as generators and pumps. Other vehicle hydraulic systems, such as those in automatic transmissions and power steering, are often equipped with an oil filter. Gas turbine engines, such as those on jet aircraft, also require the use of oil filters. Oil filters are used in many different types of hydraulic machinery. The oil industry itself employs filters for oil production, oil pumping, and oil recycling. Modern engine oil filters tend to be "full-flow" (inline) or "bypass".
Early automobile engines did not have oil filters, having only a rudimentary mesh sieve placed at the oil pump intake. Consequently, along with the generally low quality of oil available, very frequent oil changes were required. The Purolator oil filter was the first oil filter for the automobile; it revolutionized the filtration industry, and is still in production today. [1] The Purolator was a bypass filter, whereby most of the oil was pumped from the oil sump directly to the engine's working parts, while a smaller proportion of the oil was sent through the filter via a second flow path, filtering the oil over time. [2]
A full-flow system will have a pump which sends pressurised oil through a filter to the engine bearings, after which the oil returns by gravity to the sump. In the case of a dry sump engine, the oil that reaches the sump is evacuated by a second pump to a remote oil tank. The function of the full-flow filter is to protect the engine from wear through abrasion.
Modern bypass oil filter systems are secondary systems whereby a bleed from the main oil pump supplies oil to the bypass filter, the oil then passing not to the engine but returning to the sump or oil tank. The purpose of the bypass is to have a secondary filtration system to keep the oil in good condition, free of dirt, soot and water, providing much smaller particle retention than is practical for full flow filtration, the full-flow filter is still used to prevent any excessively large particles from causing substantial abrasion or acute blockage in the engine. Originally used on commercial and industrial diesel engines with large oil capacities where the cost of oil analysis testing and extra filtration to extended oil change intervals makes economic sense; bypass oil filters are becoming more common in private consumer applications. [3] [4] [5] (It is essential that the bypass does not compromise the pressurised oilfeed within the full-flow system; one way to avoid such compromise is to have the bypass system as completely independent).
Most pressurized lubrication systems incorporate an overpressure relief valve to allow oil to bypass the filter if its flow restriction is excessive, to protect the engine from oil starvation. Filter bypass may occur if the filter is clogged or the oil is thickened by cold weather. The overpressure relief valve is frequently incorporated into the oil filter. Filters mounted such that oil tends to drain from them usually incorporate an anti-drainback valve to hold oil in the filter after the engine (or other lubrication system) is shut down. This is done to avoid a delay in oil pressure buildup once the system is restarted; without an anti-drainback valve, pressurized oil would have to fill the filter before travelling onward to the engine's working parts. This situation can cause premature wear of moving parts due to initial lack of oil.
Mechanical designs employ an element made of bulk material (such as cotton waste) or pleated Filter paper to entrap and sequester suspended contaminants. As material builds up on (or in) the filtration medium, oil flow is progressively restricted. This requires periodic replacement of the filter element (or the entire filter, if the element is not separately replaceable).
Early engine oil filters were of cartridge (or replaceable element) construction, in which a permanent housing contains a replaceable filter element or cartridge. The housing is mounted either directly on the engine or remotely with supply and return pipes connecting it to the engine. In the mid-1950s, the spin-on oil filter design was introduced: a self-contained housing and element assembly which was to be unscrewed from its mount, discarded, and replaced with a new one. This made filter changes more convenient and potentially less messy, and quickly came to be the dominant type of oil filter installed by the world's automakers. Conversion kits were offered for vehicles originally equipped with cartridge-type filters. [6] In the 1990s, European and Asian automakers in particular began to shift back in favor of replaceable-element filter construction, because it generates less waste with each filter change. American automakers have likewise begun to shift to replaceable-cartridge filters, and retrofit kits to convert from spin-on to cartridge-type filters are offered for popular applications. [7] Commercially available automotive oil filters vary in their design, materials, and construction details. Ones that are made from completely synthetic material excepting the metal drain cylinders contained within are far superior and longer lasting than the traditional cardboard/cellulose/paper type that still predominate. These variables affect the efficacy, durability, and cost of the filter. [8]
Magnetic filters use a permanent magnet or an electromagnet to capture ferromagnetic particles. An advantage of magnetic filtration is that maintaining the filter simply requires cleaning the particles from the surface of the magnet. Automatic transmissions in vehicles frequently have a magnet in the fluid pan to sequester magnetic particles and prolong the life of the media-type fluid filter. Some companies are manufacturing magnets that attach to the outside of an oil filter or magnetic drain plugs—first invented and offered for cars and motorcycles in the mid-1930s [9] —to aid in capturing these metallic particles, though there is ongoing debate as to the effectiveness of such devices. [10]
A sedimentation or gravity bed filter allows contaminants heavier than oil to settle to the bottom of a container under the influence of gravity.
A centrifuge oil cleaner is a rotary sedimentation device using centrifugal force rather than gravity to separate contaminants from the oil, in the same manner as any other centrifuge. Pressurized oil enters the center of the housing and passes into a drum rotor free to spin on a bearing and seal. The rotor has two jet nozzles arranged to direct a stream of oil at the inner housing to rotate the drum. The oil then slides to the bottom of the housing wall, leaving particulate oil contaminants stuck to the housing walls. The housing must periodically be cleaned, or the particles will accumulate to such a thickness as to stop the drum rotating. In this condition, unfiltered oil will be recirculated. Advantages of the centrifuge are: (i) that the cleaned oil may separate from any water which, being heavier than oil, settles at the bottom and can be drained off (provided any water has not emulsified with the oil); and (ii) they are much less likely to become blocked than a conventional filter. If the oil pressure is insufficient to spin the centrifuge, it may instead by driven mechanically or electrically.
Note: some spin-off filters [11] are described as centrifugal but they are not true centrifuges; rather, the oil is directed in such a way that there is a centrifugal swirl that helps contaminants stick to the outside of the filter.
High efficiency oil filters are a type of bypass filter that are claimed to allow extended oil drain intervals. [5] HE oil filters typically have pore sizes of 3 micrometres, which studies have shown reduce engine wear. [12] Some fleets have been able to increase their drain intervals up to 5-10 times. [13]
Deciding how clean the oil needs to be is important as cost increases rapidly with cleanliness. Having determined the optimum target cleanliness level for a contamination control programme, many engineers are then challenged by the process of optimizing the location of the filter. To ensure effective solid particle ingression balance, the engineer must consider various elements such as whether the filter will be for protection or for contamination control, ease of access for maintenance, and the performance of the unit being considered to meet the challenges of the target set. [14]
Filtration is a physical separation process that separates solid matter and fluid from a mixture using a filter medium that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate. Oversize particles may form a filter cake on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as blinding. The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles. Filtration occurs both in nature and in engineered systems; there are biological, geological, and industrial forms. In everyday usage the verb "strain" is more often used; for example, using a colander to drain cooking water from cooked pasta.
A pump is a device that moves fluids, or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic or pneumatic energy.
A centrifuge is a device that uses centrifugal force to subject a specimen to a specified constant force - for example, to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby separating fluids of different densities or liquids from solids. It works by causing denser substances and particles to move outward in the radial direction. At the same time, objects that are less dense are displaced and moved to the centre. In a laboratory centrifuge that uses sample tubes, the radial acceleration causes denser particles to settle to the bottom of the tube, while low-density substances rise to the top. A centrifuge can be a very effective filter that separates contaminants from the main body of fluid.
A diving air compressor is a breathing air compressor that can provide breathing air directly to a surface-supplied diver, or fill diving cylinders with high-pressure air pure enough to be used as a hyperbaric breathing gas. A low pressure diving air compressor usually has a delivery pressure of up to 30 bar, which is regulated to suit the depth of the dive. A high pressure diving compressor has a delivery pressure which is usually over 150 bar, and is commonly between 200 and 300 bar. The pressure is limited by an overpressure valve which may be adjustable.
Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and becomes pressurized according to the resistance present. The fluid is controlled directly or automatically by control valves and distributed through hoses, tubes, or pipes.
A particulate air filter is a device composed of fibrous, or porous materials which removes particulates such as smoke, dust, pollen, mold, viruses and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may also remove odors and gaseous pollutants such as volatile organic compounds or ozone. Air filters are used in applications where air quality is important, notably in building ventilation systems and in engines.
Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. They are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from which it exits.
Koi ponds are ponds used for holding koi carp, usually as part of a garden. Koi ponds can be designed specifically to promote health and growth of the Nishikigoi or Japanese Ornamental Carp. Koi ponds or lakes are a traditional feature of Japanese gardens, but many hobbyists use special ponds in small locations, with no attempt to suggest a natural landscape feature.
A dust collector is a system used to enhance the quality of air released from industrial and commercial processes by collecting dust and other impurities from air or gas. Designed to handle high-volume dust loads, a dust collector system consists of a blower, dust filter, a filter-cleaning system, and a dust receptacle or dust removal system. It is distinguished from air purifiers, which use disposable filters to remove dust.
Swimming pool sanitation is the process of ensuring healthy conditions in swimming pools. Proper sanitation is needed to maintain the visual clarity of water and to prevent the transmission of infectious waterborne diseases.
The oil pump is an internal combustion engine part that circulates engine oil under pressure to the rotating bearings, the sliding pistons and the camshaft of the engine. This lubricates the bearings, allows the use of higher-capacity fluid bearings and also assists in cooling the engine.
Compressed air filters, often referred to as line filters, are used to remove contaminants from compressed air after compression has taken place.
This article briefly describes the components and systems found in jet engines.
A centrifugal water–oil separator, centrifugal oil–water separator or centrifugal liquid–liquid separator is a device designed to separate oil and water by centrifugation. It generally contains a cylindrical container that rotates inside a larger stationary container. The denser liquid, usually water, accumulates at the periphery of the rotating container and is collected from the side of the device, whereas the less dense liquid, usually oil, accumulates at the rotation axis and is collected from the center.
A magnetic chip detector is an electronic instrument that attracts ferromagnetic particles. It is mainly used in aircraft engine oil and helicopter gearbox chip detection systems. Chip detectors can provide an early warning of an impending engine failure and thus greatly reduce the cost of an engine overhaul.
A pusher centrifuge is a type of filtration technique that offers continuous operation to de-water and wash materials such as relatively in-compressible feed solids, free-draining crystalline, polymers and fibrous substances. It consists of a constant speed rotor and is fixed to one of several baskets. This assembly is applied with centrifugal force that is generated mechanically for smaller units and hydraulically for larger units to enable separation.
A conical plate centrifuge is a type of centrifuge that has a series of conical discs which provides a parallel configuration of centrifugation spaces.
The 4 VD 14,5/12-1 SRW is an inline four-cylinder diesel engine produced by the VEB IFA Motorenwerke Nordhausen from 1967 to 1990. The engine was one of the standard modular engines for agricultural and industrial use in the Comecon-countries. Approximately one million units were made.
Oil purification removes oil contaminants in order to prolong oil service life.
Gravity filtration is a method of filtering impurities from solutions by using gravity to pull liquid through a filter. The two main kinds of filtration used in laboratories are gravity and vacuum/suction. Gravity filtration is often used in chemical laboratories to filter precipitates from precipitation reactions as well as drying agents, inadmissible side items, or remaining reactants. While it can also be used to separate out strong products, vacuum filtration is more commonly used for this purpose.