Liquid purification or separation – Diverse distinct separators – Including a filter
Reexamination Certificate
1999-09-14
2002-05-14
Savage, Matthew O. (Department: 1723)
Liquid purification or separation
Diverse distinct separators
Including a filter
C210S316000, C210S323200, C210S337000, C210S338000, C210S342000, C210S452000, C210S455000, C210S483000, C210S488000, C210S489000, C210S497010
Reexamination Certificate
active
06387261
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to the field of filters for removing solids from a liquid. More specifically, the invention relates to a serviceable filter with bypass features that may be installed at the drain of a liquid holding tank such as a sink or a wash basin.
2. Description of Related Art
Filtering a flowing liquid, such as water, is desirable in many situations, such as in household drains including sinks and wash basins. Generally, filtering is desirable when a flowing liquid contains solid or liquid contaminants and foreign materials. These materials may cause problems, such as blocking conduits, if they are allowed to remain in the water especially when the water is being drained to a septic or sewer system. In drains, such as those extending from a kitchen sink, bathroom sink, or wash basins, a large amount of material can be carried by the draining water. The material may include solids, such as food particles and hair, or liquids such as oils and grease.
Conventional sinks use a bend or trap in which a fluid seal is formed by water collecting in the lower bend. The collected water prevents sewer gasses from passing back out through the drain. The purpose of these traps, is not to trap such contaminants and foreign materials. Generally, however, draining water will force solids past such traps and such solids may collect on a protuberance or be deposited on the sides of the drain conduit. The collection of solids, or contaminating liquids, such as oil or grease, in the conduit can prevent the free passage of the draining water. When a blockage is formed in the conduit downstream of the trap, it is typically removed by using chemical solvents or mechanical devices, such as an auger, commonly referred to as “snake”. Chemicals tend to be expensive, very corrosive and detrimental to the environment, while using a “snake” can be an expensive, time consuming procedure as well as labor intensive. Generally, if a mechanical device such as a “snake” is needed to remove a blockage, the services of a plumber is also required to operate it. If the clog is located in a less assessable area, a plumber may need to be called, causing a great deal of inconvenience and cost.
Devices have been developed which attempt to limit material entering the drain. These include basket and strainer devices which are received in the drain opening of a sink and prevent large solids, and to some extent, small solids, from entering the drain. In these filtration devices, the basket or strainer can also designed to be easily removed for cleaning. Such filtering devices for removing solids from a flowing liquid, such as water in a drain, are illustrated in various prior art designs.
For example, U.S. Pat. No. 965,836 to Ray discloses a sink trap including a strainer cylinder/vessel formed of screen wire or metal of finer mesh and an interior receiving pocket with perforation as its bottom. Rings, rods and other elements provide means for attachment of the device to the sink trap. U.S. Pat. No. 1,035,733 to Pierce discloses a similar sink strainer device including a drain with a nested bucket with perforations and a fine screen nested within the bucket.
However, limitations have been found with such prior art systems. Initially, it has been found that, whereas such strainers with fine mesh filtration elements provide good filtration of the water being drained, they tended to become clogged easily by the large contaminants and solids. In addition, it has also been found that when any of the filtration elements become clogged, immediate attention must be given in order to allow continued draining through the filtration devices and to prevent the back-up of the drain. Consequently, such prior art filtration devices require constant cleaning, especially with respect to the fine mesh strainers that tend to become easily clogged, making the use of such fine mesh strainers inconvenient.
Therefore, there exists an unfulfilled need for an improved filter for removing solids from a liquid with filtration elements that are easily serviceable and that provide adequate filtering of the liquid. There also exists an unfulfilled need for such an improved filter with filtration elements that incorporate a bypass feature to allow bypassing of the filtration element when it becomes clogged.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a filter for removing solids from a liquid.
A second object of the present invention is to provide an improved filter in which the filtration elements are easily serviceable.
A third object of the present invention is to provide an improved filter having nested filtration elements that provides adequate filtering of the liquid.
Yet another object of the present invention is to provide an improved filter with filtration elements that incorporate a bypass feature to allow bypassing of the filtration element when it becomes clogged.
Still further, it is an object of the present invention to provide an improved filter with a filter housing that may be easily installed on a basin of a liquid holding tank such as a sink.
In accordance with preferred embodiments of the present invention, these objects are obtained by an improved filter for removing solids from a liquid comprising a filter housing with an inlet at a top portion and an outlet towards a bottom portion, a first filtration element nested with the filter housing and having a first plurality of openings, a second filtration element nested within the first filtration element and having a second plurality of openings, where the second plurality of openings are smaller in size than the first plurality of openings and are positioned at a lower elevation below at least one opening of the first filtration element thereby allowing bypass of the second filtration element when the second filtration element is clogged. In another embodiment of the present invention, the filter also includes a third filtration element nested within the second filtration element and having a third plurality of openings where the second plurality of openings are smaller in size than the third plurality of openings and are positioned at a lower elevation below at least one opening of the third filtration element thereby allowing bypass of the second filtration element when the second filtration element is clogged.
In another alternative embodiment, the above objects are obtained by the above described filter where the first plurality of openings of the first filtration element further comprises primary openings and secondary openings, the primary openings being smaller than the secondary openings and being positioned at a lower elevation below the secondary openings in a manner to allow bypassing of the primary openings when the primary openings are clogged.
In yet another alternative embodiment, the above objects are obtained by the above described filters where the first filtration element, the second filtration element, and the third filtration element are nested within the filter housing through the inlet of the filter housing and are serviceable through the inlet of the housing. The filter may also comprise an outlet filter positioned at an opening of the outlet, a threaded annular insert for mounting through an opening in a basin of the liquid tank and a threaded connector ring for attaching the top portion of the filter housing to the threaded annular insert.
In yet another embodiment of the present invention, the drain trap filter unit may comprise a filter housing with an inlet at a top portion and an outlet towards a bottom portion, a support insert nested within the filter housing, a first filtration element nested within the support insert and a shortened filtration element nested within said first filtration element. The support insert may have plurality of support members for supporting at least one filtration element. The first filtration element may have a first plurality of openings which allows fluids to pass through the first filtration element towards the ou
Nils H. Ljungman & Associates
Ocampo Marianne
Savage Matthew O.
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