Patent Application
20170312757
The invention relates generally to filter elements and, more specifically, to a novel, non-obvious filter element having a magnetic array for assisting in the removal of ferrous particles from a fluid flow.
In the process of making hydraulic components, such as gears, pumps, motors, valves and cylinders, ferrous metal particles are produced that contaminate the fluids used in the manufacturing process. These ferrous particles can result in decreased life of the fluid system. Current ISO standards require the removal of particles down to the level of 4 microns. Filters capable of removing particulate contaminants down to 4 microns are expensive and often must be combined into a bank of filter elements in parallel or series to handle the amount of fluid flow that must be processed. When filtering oil used in manufacturing processes, magnetic are known for use in removing ferrous contaminants, including even sub-micron sized contaminants, from the fluid flow. Typically, these magnetic filters are a one-time expense and can be placed upstream of traditional filter media to help extend the life of the standard filter, thus reducing overall costs of operation.
In operational systems, such as engines, transmissions, and mobile construction equipment hydraulic systems, iron based contaminates will be generated in the normal wear and tear of operation, Typically, these metal contamination particles are relatively hard and can induce wear in a system. Many times these systems are operated outside in cold environments and putting in a fine filter medium to trap effectively these fine particles can have a negative impact on performance due to the increased pressures from the high viscosity of low temperature oil. Therefore, the filters used tend to be higher in absolute micron rating which allows larger contaminants to flow through the system and ultimately leads to lower component life. Magnetic filters can dramatically improve the filtration of the oil to much finer filtering without the cold weather bypass restrictions of a standard filter.
The present invention is a filter element having a magnetic array and which is designed to trap the most abrasive contaminates, which are ferrous based, from a fluid system with a low service cost. The filter element has an outer cylindrical can and a coaxial inner liner with a plurality of axial magnets extending substantially the length of the liner interposed in a cylindrical array either between the liner and the outer can or around the outer can. In contrast to known filters, the magnets are thus placed inside the metal can and so are more effective at trapping ferrous contaminants. The ferrous based contaminates are attracted to the liner by the magnets and held. When it is time to service the magnetic filter, the liner is removed to either be washed and reused, or simply thrown away if the liner can be made cheaply enough. The design should be modular in nature such that multiple filters can be stacked in parallel circuits to slow the flow down to maximize the contaminant removal. In some installations, the parallel system is placed in front of the standard filter to act as both an absolute filter as well as an indicator when to service the system. Other versions could be made to target specific markets such as diesel engines used in transportation and logistics, as well as other markets.
In a preferred embodiment, a spiral baffle is placed inside the filter to increase the flow path of fluid through the filter, thereby also increasing residence time in the filter, and to direct the higher density contaminants toward the liner at outer wall of the filter where the magnetic filed is the strongest and where trapping of the ferrous contaminants is most effective. An advantage of the spiral flow path is that it has a constant cross-sectional area which eliminates restrictions in the fluid flow path. Alternatively, an insert which induces a vortical flow of the fluid along the axis of the filter can be used.
In another preferred embodiment, the magnets are arranged in pairs of alternating polarity. Alternatively, they may be arranged in a spaced relationship with adjacent magnets having alternating polarity.
In another preferred embodiment, multiple filter elements of the present invention are arranged in series to increase the holding capacity of trapped contaminants. Alternatively, multiple magnetic filter elements of the present invention may be arranged in parallel arrays that will slow down the fluid flow through each element, thereby increasing the residence time in each element to allow more time for trapping of the ferrous contaminants. The stacked and parallel arrays can be combined with a filter having standard filtering medium to catch non-ferrous contaminants for absolute filtration capability. The standard filter can then use a pressure differential detection across the filer medium to indicate when to check the magnetic array filter elements for cleaning.
In another embodiment, an air purge can be used to push fluid out of the array to facilitate changing of the filter elements.
In an alternative embodiment, the stacked arrays of the standard filter element and the magnetic array filter elements of the present invention may be assembled in two parallel circuits such that one side of the two parallel circuits can be serviced while the other side remains operational.
There is, accordingly, an interest in developing a magnetic arrays filter element with more effective trapping characteristics and which can be more easily serviced.
Illustrated in
In certain embodiments, it may be desirable to induce a predetermined flow pattern of the fluid inside the filter element 10 so as to improve the filtering efficiency of the filter element 10. For example, inducing a vortex in the fluid around the longitudinal axis will increase the residence time of the fluid inside the filter element 10 and will also cause a centripetal force that will urge the higher density ferrous contaminants toward the liner 18 and arrays of magnets 28. The vortex can be induced by angling of the port 24 and by selecting a shape and placement of the plates 26 that will help maintain the vortical flow.
Illustrated in
A further preferred embodiment is illustrated generally at 210 in
The individual magnets 130 may be arranged in at least two different ways. The magnets may be arranged in adjacent pairs of alternating polarity, as illustrated in
In certain applications, it may be preferable to provide a port in the bottom plate 16, 116 through which compressed gas can be directed into the filter housing 12, 112, to assist in purging fluid from the filter 10, 110.
An alternative embodiment is illustrated in
Oil to be filtered is introduced into the filter 210 at inlet 230 and is removed from the filter 210 at outlet 232. The path of the oil inside the filter 210 is determined by the arrangement of the removed sections 226 of the stacked spacer plates 224. Since the removed sections 226 alternate sides of the filter 210 as described, the oil is forced to go from one side of the filter 210 to the other side as it encounters each spacer plate 224. The path of the oil through the filter 210 is thus increased as is the residence time it spends near the circumferential periphery of the filter 210. The oil thus has a stepped flow path in contrast to the spiral flow path of the filter 10. A series of magnet arrays 228, similar to those described in the other embodiments are arranged outside the filter housing 212 and will serve to trap ferrous contaminants against the non-ferrous liner 218. An advantage of the embodiment filter 210 is that the stacked spacer plates can be easily and inexpensively manufactured, for example, by laser cutting.
The foregoing description and drawings comprise illustrative embodiments of the present inventions. The foregoing embodiments and the methods described herein may vary based on the ability, experience, and preference of those skilled in the art. Merely listing the steps of the method in a certain order does not constitute any limitation on the order of the steps of the method. The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited. Those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention.
