Reusable fluid filter having filtering and additive functions

Abstract: This invention relates to a reusable filter unit for a fluid system such as used on an internal combustion engine or the like wherein the filter fulfills both a filtering function and an additive function, the filter including a filtering part (30) with replaceable filtering media (16) and an additive part (29) adapted to receive replaceable chemical additives. The filtering part (30) includes a generally toroidal shaped plastic element (15) for receiving a generally cone shaped replaceable filter media (16), which can be agglomerated fiber, the element (15) fitting into, and permanently bonded to, an outer shell (27), with the additive part (29) being located below the element (15). The filter could be used in any system which requires fluid filtering with an additive function, for example, central heating applications for buildings.

Description: INTRODUCTION This invention relates to a reusable filter unit which could be used, for example, in internal combustion engines, such as diesel or gasoline powered engines, or in central heating applications for buildings, or the like, wherein the filter provides both a filtering and an additive function. The filter can be used for a variety of fluid media, although the preferred embodiment describes a filter intended for fluid (which might be water) filtering purposes, used in the engine's cooling system. Filters having both filtering and additive functions are known in the art. Such filters have a filtering part which might include a paper filter media, and an additive part which might conventionally contain additives which can be used to treat the filtered fluid, such as anti-corrosion or anti-pitting additives. These prior art dual function filters, however, suffer from a number of drawbacks. They are of a relatively complex construction, consisting of numerous parts, which render them difficult and expensive to manufacture. Also, these dual function filters are not reusable. When the filtering media within the filter become polluted with removed impurities, and/or when the chemical additive is exhausted, the filter must be discarded, or essentially reconstructed. Further, because of the complexity of the prior art units, they must be made largely of metal in order to withstand the constructional forces. It is an object of this invention to provide a filter which alleviates the disadvantages of the prior art devices. Specifically, it is an object of this invention to provide a filter which provides both a filtering and an additive function and which can be reused in that the filtering media and the additive can be replaced easily and conveniently without disassembling or reconstructing the device. Further, it is an object of this invention to provide a filter which is relatively simple and inexpensive to construct and which is particularly adapted to be constructed of plastic components. BRIEF DESCRIPTION OF DRAWINGS Figure 1 shows a prior art dual function filter unit. Figure 2 is a sectional side view of the filter according to the invention. Figure 3 is a sectional perspective view of the filter according to the invention. Figures 4 and 5 are perspective views of the filtering part of the filter according to the invention. Figure 6 is a bottom view of the filtering part. Figure 7 is a sectional perspective view of the filtering media which is used in the filter according to the invention. DETAILED DESCRIPTION OF DRAWINGS Figure 1 shows a typical prior art filter which includes both a filtering part and an additive part. Such a filter would be used in, for example, the cooling system of a diesel engine for coolant filtering. The filter would be connected to the fluid system with the upper portion, as seen in Fig. 1, of the filter being mounted on a suitable receiving means located on the fluid system. The medium to be filtered, which might be water or another fluid, would leave the fluid system and enter the open upper portion of the filter as shown by the arrow in Fig.1. The fluid would then pass through opening (1) and enter the body of the filter where it would encounter filtering media (2). Filtering media (2) consists, conventionally, of pleated paper assembled around a tube to form a star or cylinder of treated paper, which typically would be heated, or cured, prior to use. Filtering media (2) is attached to a lower end plate (3), which is made of metal. Filtering media (2) is held in place on the lower end of plate (3) by means of adhesive material (4). Upper metal plate (5) is affixed to the upper end of filtering media (2), this also being held in place by adhesive material. In operation, fluid would pass through the filtering media (2) towards the center of the filter. The inner wall of filtering media (2) rests against a perforated center tube (6) which includes a plurality of holes which allows the fluid to enter into the center, or additive, portion of the filter. In the additive portion of the filter there is located an additive product (7) which could be solid, granular, or paste. The fluid would pass through the additive product and will carry with it a certain amount of this additive, which will then be distributed throughout the fluid system. The additive (7), commonly called "supplemental chemical additive" (SCA) or "dry chemical additive" (DCA), can be used for a variety of purposes, such as preventing corrosion or pitting in a cooling system. After being treated with the additive, the fluid will pass through a central aperture (not shown) in the upper end plate (5) and into the fluid system. At the bottom of Fig. 1 is seen spring (8) which acts upon the lower end plate (3) to force the entire central portion of the filter in an upward direction so that the ridge (9) in the upper metal plate (5) will press against the metal nut plate (10), a gasket or seal being interposed between the ridge (9) and plate (10). This closure prevents the entering fluid from passing directly to the exit of the filter without passing through the filtering and additive portions. The entire filtering unit is contained within a metal shell (11). There are a number of disadvantages with the above described prior art structure. The device is relatively heavy as it must be made of metal for strength and is complex to construct. Further, the device is a "throw away" structure, that is, it is constructed with the filter and additive permanently in place, and when these elements are exhausted, the filter is not reusable, but rather must be discarded and replaced by a new filter having new filtering media (2) and new additive (7). A further prior art filter is seen in EP-A-0 273 720. The filter according to the invention is seen in Figs. 2 through 7. The filtering part of the filter unit is the top portion as seen at (30) in Fig. 2, and the additive part is seen below at (29). The flow of fluid through the filter is indicated by the arrow in Figures 2 and 3. As seen in the Figs. 2 and 3, the fluid enters the filter through fluid input aperture (14) and passes into a toroidal shaped plastic element (15) which constitutes a means for retaining the filter media, where it encounters filtering media (16). The retaining means (15) forms a toroidal shaped cavity (22), open at the upper surface, having cylindrical or conical inner walls (17), which, as seen in Fig. 3, are connected by element (26) which is molded integrally as a part of the retaining means (15) to form a single piece element, as seen in Figs. 4, 5, and 6. The filtering media (16) is in the form of a cone open at both ends, and having an outer surface which contains a plurality of protrusions as is seen in Fig. 2. Filtering media (16) is preferably a solid element made of fibers (natural, synthetic, or mixed) agglomerated together by resins, binders, or other means such as thermobonding. The filtering media (16) self centers and seals into retaining means (15) between outer chamber wall (24) and inner chamber wall (17). In operation, the fluid passes through filtering media (16) and flows between the inner wall of filtering media (16), and retaining means inner wall (17) in a downwardly direction. The now filtered fluid passes below the filtering media into the lower part of the retaining means. The filtered fluid then passes through additive aperture (18) and enters the lower, or additive, part (29) of the filter. The additive part (29) of the filter contains an additive product (19). This additive product is typically in a paste, granule, or liquid form. The additive, as discussed above, is used to treat the fluid with, for example, anti-corrosion or anti-pitting chemicals. The fluid passes through the additive and mounts in an upwardly direction as seen in Figs. 2 and 3 and passes through output aperture (20) and reenters the fluid system. The output aperture (20) is located in connecting element (26) which connects the inner walls (17) of the retaining means (15). Outer shell (27) is preferably a single piece plastic unit. Outer shell (27) is permanently connected to retaining means (15) at joint (28) by, for example, fusion welding. The retaining means (15), like the shell, is also preferably a single piece plastic unit and thus, the filter can consist of only two elements, permanently bonded. As is best seen in Fig. 3, threads are provided in the inner central portion of the retaining means (15) at (21). These threads will be screwed upon a corresponding element on the fluid system in order to affix the filter unit to the fluid system. There is also provided a gasket (23) which ensures fluid tightness at the outer periphery of the filter. Figures 4 and 5 are two perspective views of the retaining means (15). Figure 4 shows the fluid input aperture (14) into which the fluid from the fluid system would enter the retaining means. The filtering media (16) (not shown in Figure 4) would fit into thoroidal shaped cavity (22) slipping over the central post element (13). The upper portion of the output aperture through which fluid will re-enter the fluid system is seen at (20). Plastic re-enforcing ribs, which are preferably molded of one piece integral with the retaining means (15) are seen at (12). Figure 5 shows another perspective view of the retaining means (15) depicting another view of the reinforcing elements (12). An additive aperture is seen at (18); preferably, there would be a plurality of additive apertures, for example, one between each of the reinforcing ribs (12). Figure 6 shows a bottom view of the retaining means (15) wherein a plurality of additive apertures are seen at (18) between reinforcing ribs (12). Figure 7 shows replaceable filtering media (16) removed from the filter. Filtering media (16) is a solid element having a saw-tooth like outer surface (24), which is provided so that the filtering media will have the maximum outer surface area. The filtering media is preferably made from agglomerated acrylic fibers held together by phenolic resin. Preferably, the media has so-called "growing porosity" which means that the porosity is reduced from the outer surface of the filter towards the inner surface, this ensuring that the particles will be trapped in the depth of the media. There are considerable advantages accruing to the above described design. The unit is of a fixed construction in that the retaining means (15) is permanently welded to the outer shell (27), which makes the unit easy and inexpensive to manufacture. Despite this fixed construction, the filter is entirely reusable. After the unit has been in operation for a period of time and the filter media is polluted, and/or the additive exhausted, these may be replaced without discarding the filter in its entirety or disassembling and rebuilding the filter. This is accomplished according to the invention as follows. The filter would be unscrewed from the fluid system via threads (21). With the filter removed from the system, the solid filtering media (16), would be exposed as seen in Fig. 3. The operator would then simply lift out this solid filtering media (16) and discard it. Once the filter media (16) is removed, additive apertures (18) at the bottom of the retaining means (15) would be exposed. The operator can then simply pour out any remaining additive by turning the filter up-side down and can then add new liquid, granular, or paste additive into retaining means (15), this new additive flowing downwardly through the additive apertures (18) into the additive part (29) of the filter. After the new additive has been added to the filter, the operator would then slip on another filtering media element (16) and the filter would then be in an entirely refreshed state. There is thus provided a reusable filter which has both filtering and additive functions, wherein both the filtering media and the additive can be replaced without disassembling and reassembling the unit, and, further, having an extremely simple construction consisting, in essence, of two inexpensive single piece plastic elements, retaining means (15) and outer shell (27) which are permanently bonded to form a filter unit which, although reusable, need never be disassembled.

Claims: A reusable filter for a fluid system such as used on an internal combustion engine, or central heating system, the filter including a filtering part (30) and an additive part (29), the filtering part being adapted to receive a disposable filtering media (16) and the additive part being adapted to receive replaceable chemical additives (19); the filtering part (30) including a means for retaining (15) the filtering media (16), the means for retaining including an input aperture (14) for receiving fluid to be filtered from the fluid system and an output aperture (20) for returning the filtered fluid to the fluid system after it has passed through the filtering media (16) and the additive part (29), the filtering part being disposed between the additive part and the fluid system. the filtering media (16) being removeable and replaceable via said fluid input aperture (14) when the filter is removed from the fluid system; the retaining means (15) including an additive aperture means (18) for allowing filtered fluid to pass into the additive part (29) after having passed through said filtering media (16), said additive aperture means (18) also being adapted for allowing replacement additive to be added to the additive part (29) when the filter is removed from the fluid system and the filtering media (16) has been removed from the retaining means (15) prior to replacement. The filter according to claim 1 wherein the retaining means (15) includes a toroidal shaped cavity (22) with the input aperture (14) being located generally opposite the additive aperture means (18), the filtering media (16) fitting into said cavity (22) between the input aperture (14) and the additive aperture (18). The filter according to claim 2 wherein the filter media (16) includes agglomerated fibers with resin and constitutes a single replaceable element having a complex outer surface for increasing the outer area of said outer surface. The filter according to claim 3 wherein the filter media is frustro-conical in shape and is thereby self centering and self sealing into the retaining means (15) between the outer chamber wall and inner chamber wall (17). The filter according to claim 4 wherein the outer shell (27) and the retaining means (15) each consists of a one piece plastic element and are permanently bound together by fusion welding. The filter according to claim 2 wherein the retaining means (15) includes an outer wall (24) and an inner wall (17) located on either side of said additive aperture means (18) and said input aperture (14), said inner wall being essentially frustro-conical, and including a connecting element (26) for connecting the inner wall (17) of the retaining means (15). The filter according to claim 6 wherein the said output aperture (20) is located in the said connecting element (26) of the retaining member (15). The filter according to claim 1 wherein the retaining means (15) is shaped generally as a toroid having an open end for receiving unfiltered fluid input and the surface opposite said open end containing the additive fluid means (18) and wherein the said filtering media (16) and the said additive (19) are replaceable without disassembling the filter unit through the said open surface when the filter is removed from the engine.

Inventors: BOUCHET JEAN-YVES, FERTIL DANIEL, GOURITIN PATRICE, BOUCHET, JEAN-YVES, FERTIL, DANIEL, GOURITIN, PATRICE
Applicants: FLEETGUARD
Application year: 1992
Main classification: F01P11
IPC codes: F01P11, B01D37, B01D29