Method and apparatus for metal removal from drinking water

Abstract

A single sheet water filter media for gravity filtration applications that improves flow performance over the product life while maintaining sufficient metal reduction, wherein at least two distinct density gradients of the single sheet form a physical barrier for capturing colloidal and insoluble contaminants, retaining the colloidal and insoluble contaminants until the contaminants become soluble in the fluid, and being removed by the single sheet filter media. The single sheet filter overcomes the difficulties of dual- and multi-layer filters attributable to slower flow rate realized well before the rated lifetime of the product. The two distinct density gradients of the single sheet filter media are created by exerting a force on a liquid slurry, such force resulting in the separation of higher powder loading and fibers that compose the top and bottom density gradients, respectfully.

Description

BACKGROUND OF THE INVENTION1. Field of the Invention[0001]The invention relates to water filtration, and particularly to a water filter for gravity filtration applications that improves flow performance over the product life while maintaining sufficient metal reduction, such as lead reduction. More specifically, the invention relates to a single sheet filter that overcomes the difficulties of dual- and multi-layer filters attributable to slower flow rate realized well before the rated lifetime of the product.2. Description of Related Art[0002]Although used in numerous consumer products, metals, such as lead, can be toxic, and are now known to be harmful to human health if inhaled or ingested. Important sources of lead exposure include: ambient air, soil, and dust (both inside and outside the home), food (which can be contaminated by lead in the air or in food containers), and water (from the corrosion of plumbing). Materials such as ion exchange resins and reverse osmosis membranes ...

AI Technical Summary

Benefits of technology

The patent text describes a new filter media that can remove soluble, colloidal, and insoluble particles, including lead, without the need for multiple layers. This new filter media improves flow performance and prevents the growth of bio-slime in gravity filtration applications. It is also more efficient than current dual-layer filter media and avoids issues of air entrapment and inflammation.

Problems solved by technology

Although used in numerous consumer products, metals, such as lead, can be toxic, and are now known to be harmful to human health if inhaled or ingested.

However, these filters have deficiencies that make them less than optimum for certain applications.

For example, the multiple layers of filter media, forming multiple physical barriers to capture contaminants such as lead and other metal particulate, have experienced difficulties due to decreasing flow rate well before the expected lifetime performance duration of the filter product.

Furthermore, steady flow rates are difficult to achieve in these multi-layered filter media due to the occurrence of air entrapment in the space between the first and second filter layers.

When such air entrapment occurs between the layers of these prior art designs, the flow rate through such filters is drastically reduced and thus filtration efficiency is significantly hindered.

City water is subject to bubbling (as opposed to lab water which is substantially more “still”), which slows the flow of water down and increases the chance of air entrapment, especially between the layers of a dual filter media, such as that disclosed in U.S. Pat. No. 8,002,990, resulting in the measurements for the filter media under city water conditions being demonstratively poorer than the lab water measurements.

It is noted here that both variations of the A7A7 prior art (labeled “A7A7” and “A7A7_2”) failed the lead performance test entirely—they were not successful in efficiently filtering lead / metal particulates from the influent.

These problems arise in part from having a filter media interface that physically entraps colloidal and insoluble particulates therein, and holds them indefinitely.

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