Patent Description:
Filtration systems are traditionally considered a fluid treatment and can also be considered as a part of contamination management. Contamination management is defined herein as relating to the analysis and optimization of processes with regard to the cleanliness of components, systems and the purity of the fluids used. In modern hydraulic systems smaller, lighter, and more powerful components are currently being used compared to only a decade ago. The use of these components also means that the demand of system cleanliness is now much higher, as has been shown by various studies. As much as <NUM>% of all hydraulic system outages are due to increased contamination. This failure rate applies to more than classic hydraulics industry. Contamination management, such as through the design and implementation of appropriate filter assemblies, is a key issue in the design and maintenance of hydraulic or fluid power systems used in a general sense for all industries.

In general, filtration systems include i) disposable units in which the filtration media and housing are integrated into a single use unit, often called "spin-ons" due to a commonly implemented threaded attachment technique; ii) filter assemblies having replaceable units in which the filtration media is formed in a filter element (AKA a filter cartridge) that can be removed from a unit housing forming a filter assembly; and iii) filtration units with cleanable media, which are cleaned by a process such as back-flushing.

Thus, a filter element, also called a filter cartridge, within the meaning of this application, is a unit including filter media that is configured to be received in a filter assembly housing and is sometimes referenced as a drop in element. The filter assembly is one, or more, filter housings and associated filter elements together with other components of the unit such as a control, test points, particle counters, bypass valves, etc..

The maintenance of a filter assembly having replaceable filter elements obviously requires the periodic replacement of the filter elements. One difficulty is that the replacement filter element must be suitable for the application in which it is being placed. The system can easily breakdown if a replaceable filter element is replaced with a filter element not rated for the particular application.

<CIT> discloses a filter assembly according to the preamble of claim <NUM>, comprising: a filter element housing; an authenticating filter element coupling; and a replaceable drop-in twist locking filter element, wherein the housing includes a keyed bushing coupled thereto that provides an authenticating mechanism for a replaceable filter element suited for the specific housing wherein the keyed bushing forms one half of the authenticating coupling for the filter assembly.

Additional filter assemblies are disclosed in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

There is a need for a cost effective, efficient, filter assembly with replaceable filter elements which can easily authenticate replacement filter elements.

According to claim <NUM>, a filter assembly is provided, comprising:.

wherein the housing includes a keyed bushing coupled thereto that provides an authenticating mechanism for a replaceable filter element suited for the specific housing wherein the keyed bushing forms one half of the authenticating filter element coupling for the filter assembly.

wherein the housing includes a keyed bushing coupled thereto that provides an authenticating mechanism for a replaceable filter element suited for the specific housing wherein the keyed bushing forms one half of the authenticating filter element coupling for the filter assembly,.

Both filter assemblies are characterized.

This invention is directed to a cost effective, efficient, filter assembly with authenticating filter element coupling and replaceable drop-in twist locking filter element therefor. A filter assembly includes an authenticating filter element coupling, formed of the combination of a keyed bushing and locking guide, and replaceable drop-in twist locking filter element therefor. The keyed bushing is coupled a housing of the filter assembly and provides an authenticating mechanism for a replaceable filter element suited for the specific housing wherein the keyed bushing forms one half of the authenticating filter element coupling for the filter assembly. The locking guide is coupled to an endcap of a filter element and the locking guide has a sleeve with slots in an end thereof that match keys of the associated keyed bushing on a filter housing. The locking guide forms one half of the authenticating coupling for the filter assembly.

One aspect of the invention provides a filter assembly including a filter element housing an authenticating filter element coupling; and a replaceable drop-in twist locking filter element. The housing includes a keyed bushing coupled thereto that provides an authenticating mechanism for a replaceable filter element suited for the specific housing wherein the keyed bushing forms one half of the authenticating filter element coupling for the filter assembly. The filter assembly may provide wherein the keyed bushing includes a set of uniquely arranged keys on the radial periphery of the bushing. The filter assembly may provide wherein the keyed bushing includes a flange configured to rest on the housing and a sealing surface above the specific keys. The filter assembly may provide wherein the filter element includes an endcap with a sealing O-ring wherein the sealing surface is to be engaged with a sealing O-ring of the end cap of the filter element. The filter assembly may provide wherein the authenticating filter element coupling for the filter assembly includes a locking guide having a sleeve with slots in an end thereof that match the keys of the associated keyed bushing.

These and other advantageous aspects of the invention will be clarified in connection with the attached figures in which like reference numerals represent like elements throughout.

The embodiments of <FIG> merely pertain to the background of the invention and are not claimed.

This invention is directed to a cost effective, efficient, filter assembly <NUM> shown in <FIG> with a filter element housing <NUM> having an inlet/outlet <NUM>, outlet/inlet <NUM> and bypass valve <NUM>. Component <NUM> is an inlet and <NUM> an outlet when designed for outside-in flow and vice versa for inside-out flow. The bypass valve <NUM> is orientated to allow for bypass from the inlet (<NUM> or <NUM>) to the outlet (<NUM> or <NUM>) during blinding or clogging of the filter element, and obviously as shown will operate in only one direction. The configuration of the bypass valve <NUM> from that shown would change with a change in operational flow direction of the assembly <NUM>.

As described below the invention is directed to a filter assembly <NUM> with an authenticating filter element coupling, formed of the combination of a keyed bushing <NUM> and locking guide <NUM>, and replaceable drop-in twist locking filter element <NUM> therefor.

The housing <NUM> includes a keyed bushing <NUM> coupled thereto that provides an authenticating mechanism for a replaceable filter element suited for the specific housing <NUM>. The bushing <NUM> is press fit or threaded onto the housing <NUM>.

The keyed bushing <NUM> forms one half of the authenticating coupling for the filter assembly <NUM>. The keyed bushing <NUM> is shown individually in <FIG> and includes a set of uniquely arranged keys <NUM> on the periphery of the bushing that are associated with, or in other words that define, a specific filter element rating/configuration for the assembly <NUM>. The specific radial positioning of three keys <NUM> are believed to be sufficient to yield an extremely large number of unique key arrangements. Given that the specific keys <NUM> may have varied widths the possible unique position and size arrangements of three keys is effectively limitless.

The keys <NUM> are orientated parallel to each other as opposed to radially extending so as to improve molding and allow simple two-piece mold construction. The keyed bushing includes a flange <NUM> to rest on the housing <NUM> and a sealing surface <NUM> above the specific keys <NUM>. The sealing surface <NUM> is to be engaged with a sealing O-ring of the end cap <NUM> of the filter element <NUM>. The inner diameter of the bushing <NUM> includes a notch <NUM> that assures the proper sealing occurs on the sealing surface <NUM> rather than on the inside surface.

The authenticating coupling for the filter assembly <NUM> includes a locking guide <NUM> shown in <FIG>. The locking guide <NUM> forms one half of the authenticating coupling for the filter assembly <NUM> and includes a sleeve <NUM> with slots <NUM> in an end thereof that match the keys <NUM> of the associated keyed bushing <NUM>. The sleeve <NUM> includes a detent member <NUM> or simply a detent <NUM> in the form of a ramp and perimeter stop that will engage with and secure one key <NUM> upon insertion and rotation of the filter element <NUM> and guide <NUM> relative to the keyed bushing <NUM>.

The leading key <NUM> will engage the ramp of the detent <NUM> and create a tight function lock with the stop of the detent <NUM> preventing further rotation. The locking guide <NUM> includes interconnect tab structures <NUM> for coupling a specific locking guide <NUM> to a given end cap <NUM> of a filter element <NUM>. The locking guide <NUM> together with the keyed bushing <NUM> form an authenticating coupling and are unique to a given filter assembly rating or classification. Thus, only a filter element <NUM> with a matching locking guide <NUM> can be used with a given assembly <NUM> having the bushing <NUM>.

The locking guide <NUM> is secured to an endcap <NUM> of a filter element <NUM>. The guide <NUM> may effectively be epoxied onto the endcap <NUM> and be integral therewith after coupling. The endcap <NUM> is shown in <FIG> and includes a sleeve <NUM> with radial sealing O-ring <NUM>. The sleeve <NUM> of the endcap <NUM> receives the sealing face <NUM> of the keyed bushing <NUM> and the O-ring <NUM> seals against the sealing face <NUM>. The slots <NUM> receive tabs <NUM> that engage detents <NUM> to secure the locking guide to the end cap <NUM>. The construction and operation of slots <NUM> detents <NUM> and associated tab structure <NUM> is well known in the art and can take many forms for interconnecting these components. The filter element <NUM> includes filter media <NUM> extending between the endcap <NUM> and an upper endcap <NUM>. The filter media <NUM> can be pleated media or composite media structures or any desired configuration.

In operation when a given filter assembly <NUM> is designed then a unique keyed bushing <NUM> is developed and coupled to the assembly <NUM>. The unique keyed bushing <NUM> matches with an associated locking guide <NUM> that is coupled to replaceable filter elements <NUM> having the designated rating for the assembly <NUM>.

<FIG> is a perspective view of a modified keyed bushing <NUM> of a modified authenticating filter element coupling of a filter assembly <NUM> of the present invention. Here the sealing face <NUM> is a radial flange <NUM> rather than a circumferential face, but still provides unique radial keys <NUM> (four in this embodiment).

<FIG> is a perspective view of a modified integrated endcap and locking guide <NUM> of the modified authenticating filter element coupling of <FIG>. Here the sealing O-ring <NUM> is radially outside of the slots <NUM> that are sized to receive and match the keys <NUM>. A detent <NUM> receives the keys <NUM> when twisted into position after insertion. In this embodiment the portion of the endcap and integrated locking guide <NUM> radially within the O-ring <NUM> could easily be formed by a grommet that is popped into a more generic outer portion.

The position of the keyed bushing <NUM> on the housing <NUM> and the locking guide <NUM> may be reversed with the bushing <NUM> on the endcap <NUM> and the locking guide <NUM> on the housing <NUM>.

<FIG> illustrates a modified integrated endcap and key-shaped bushing <NUM> of a modified authenticating filter element coupling of the present invention. The endcap and key-shaped bushing <NUM> forms an endcap for a filter element <NUM> and includes an inner sleeve <NUM> and an outer sealing O-ring <NUM> sealing against a sealing face of a sleeve of a locking guide (not shown). In this embodiment, instead of keys <NUM> on the bushing <NUM>, the outer perimeter <NUM> is formed of a unique profile (here a rounded square) that matches with a unique profile of the locking guide (not shown) to form the authenticating coupling. Without the complementary shaped components, the O-ring seal <NUM> will not forma seal even if the bushing <NUM> were to fit. The embodiment of <FIG> is not a twist to lock arrangement, but is merely linearly advanced into position. The embodiment still provides the authentication desired.

Claim 1:
A filter assembly (<NUM>) comprising:
- a filter element housing (<NUM>);
- an authenticating filter element coupling (<NUM>, <NUM>); and
- a replaceable drop-in twist locking filter element (<NUM>),
wherein the housing (<NUM>) includes a keyed bushing (<NUM>) coupled thereto that provides an authenticating mechanism for the replaceable filter element (<NUM>) suited for the specific housing (<NUM>) wherein the keyed bushing (<NUM>) forms one half of the authenticating filter element coupling (<NUM>, <NUM>) for the filter assembly (<NUM>),
characterized
in that the keyed bushing (<NUM>) includes a set of uniquely arranged keys (<NUM>) on the radial periphery of the bushing (<NUM>); and
in that the keyed bushing (<NUM>) includes a flange (<NUM>) configured to rest on the housing (<NUM>) and a sealing surface (<NUM>) above the keys (<NUM>).