Gravity flow filter

• US 8,167,141 B2
• Filed: 09/09/2008
• Issued: 05/01/2012
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Brita LP (Clorox Company)
• Original Assignee: Brita LP (Clorox Company)
• Inventors: Knipmeyer, Elizabeth L., Lynch, Toni L., Reid, Roger P., Saaski, Bruce D.
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): Gonzalez, Madeline
• Application Number:
  US12/207,284
• Publication Number:
  US 20090001011A1
• Time in Patent Office: 1,330 Days
• Field of Search: None
• US Class Current: 210/464
• CPC Class Codes: B01D 2239/0407 comprising particulate additives, e.g. adsorbents apparatus incorporating gas filtering material B01D46/0036
• CPC Class Codes: B01D 2239/0421 Rendering the filter material hydrophilic
• CPC Class Codes: B01D 2239/0428 Rendering the filter material hydrophobic
• CPC Class Codes: B01D 2239/1241 Particle diameter
• CPC Class Codes: B01D 39/2062 Bonded, e.g. activated carbon blocks
• CPC Class Codes: C02F 1/003 using household-type filters for producing potable water, e.g. pitchers, bottles, faucet mounted devices C02F9/20 takes precedence
• CPC Class Codes: C02F 1/283 using coal, charred products, or inorganic mixtures containing them
• CPC Class Codes: C02F 2201/006 Cartridges
• CPC Class Codes: C02F 2307/04 as part of a pitcher or jug

Abstract

A gravity-fed carbon block water filter in one embodiment includes a filter block comprising multiple sub-blocks each comprising filter media walls surrounding and defining a cavity for receiving fluid. Each of the sub-blocks is connected to at least one other of the sub-blocks by filter media of which the filter block is made. In one approach, the filter media includes about 20-90 wt % activated carbon, and about 5-50 wt % binder. In another approach, a lead concentration in a final liter of effluent water filtered by the filter is less than about 10 μg/liter after about 151 liters (40 gallons) of source water filtration, the source water having a pH of 8.5 and containing 135-165 ppb total lead with 30-60 ppb being colloidal lead greater than 0.1 μm in diameter. A gravity-fed water filter in other embodiments has no specified shape but achieves a FRAP factor of about 350 or less.

Claims

1. A gravity-fed water filter, comprising:

filter media including at least activated carbon and a lead scavenger;

wherein the filter achieves a Filter Rate and Performance (FRAP) factor of about 350 or less according to the following formula;

2. The water filter as recited in claim 1, wherein the filter achieves a FRAP factor of less than about 200.

3. The water filter as recited in claim 1, wherein the volume of the filter media (V) is less than about 300 cm³.

4. The water filter as recited in claim 3, wherein the volume of the filter media (V) is less than about 150 cm³.

5. The water filter as recited in claim 1, wherein the average filtration unit time (f) is less than about 12 minutes per liter.

6. The water filter as recited in claim 5, wherein the average filtration unit time (f) is less than about 6 minutes per liter.

7. The water filter as recited in claim 1, wherein the filter media is present in the form of a block.

8. The water filter as recited in claim 7, further comprising a binder material interspersed with particles of the activated carbon.

9. The water filter as recited in claim 8, wherein the binder material has a melt index that is less than 1.8 g/10 min as determined by ASTM D 1238 at 190°

C. and 15 kg load.

10. The water filter as recited in claim 8, wherein the binder material has a melt index that is about 1.0 g/10 min as determined by ASTM D 1238 at 190°

C. and 15 kg load.

11. The water filter as recited in claim 7, wherein the filter fits within a container having a volume of less than about 20 in³.

12. The water filter as recited in claim 7, wherein the filter fits within a container having a volume of less than about 10 in³.

13. The water filter as recited in claim 7, wherein the block comprises multiple sub-blocks, each of the sub-blocks comprising filter media walls surrounding and defining a cavity for receiving fluid.

14. The water filter as recited in claim 7, wherein the block comprises multiple sub-blocks, each of the sub-blocks comprising filter media walls surrounding and defining on four sides a cavity for receiving fluid.

15. The water filter as recited in claim 13, wherein the block has an exterior space, gap, or recess between at least a portion of the multiple sub-blocks.

16. The water filter as recited in claim 7, wherein the block has an open top for receiving unfiltered water into a cavity thereof.

17. The water filter as recited in claim 7, wherein a median sidewall thickness of the block is less than about 0.6 inch.

18. The water filter as recited in claim 7, wherein a median sidewall thickness of the block is less than about 0.4 inch.

19. The water filter as recited in claim 7, wherein a structure of the block is characterized by having been compressed no more than 10% by volume during fabrication of the filter.

20. The water filter as recited in claim 1, wherein the filter media comprises primarily particles that are not bound together.

21. The water filter as recited in claim 1, wherein the filter media is present in the form of granular carbon.

22. The water filter as recited in claim 1, wherein the lead scavenger is a zirconia oxide or hydroxide.

23. A gravity-flow system for filtering water, comprising:

a container having a source water reservoir than can hold source water and a filtered water reservoir that can hold filtered water;

a cartridge in communication with both the source water reservoir and the filtered water reservoir, the cartridge providing a path through which water can flow from the source water reservoir to the filtered water reservoir; and

a filter as recited in claim 1 disposed within the cartridge.

24. The gravity-flow system as recited in claim 23, wherein the cartridge has an aperture through a sidewall thereof for allowing at least egress of air into the filtered water reservoir.