Carafe filter with air lock prevention feature

Abstract

A filter for gravity-fed applications, having filter media with a hollow center, the filter being generally prone to a degradation or cessation in fluid flow due to air entrapment or air lock within the filter housing cavity, which develops during filtering. A diffuser element is introduced to pierce the entrapped air bubble, the diffuser element being an elongated structure connected to the filter housing top end cap and extending through the entrapped air bubble to the filter media.

Claims

1. A filter for gravity-fed applications comprising: a top cap having fluid ingress apertures and in fluid communication with a filter media; said filter media having a top end, a bottom end, and a hollow center; a filter media top end cap attached to said filter media at said top end, said filter media top end cap in fluid communication with said top cap; a bottom cap attached to said filter media at said bottom end; and a diffuser extending from said top cap to said filter media hollow center through said filter media top end cap, and within a top portion of said filter media hollow center; wherein said top cap is substantially submerged by fluid during filtration, and said diffuser pierces any air bubble formed in said hollow center during said filtration.

2. The filter of claim 1 wherein said filtration includes submerging at least said top cap of said filter in fluid under gravity, and having said fluid enter said filter media through said hollow center, and traverse radially outwards through sidewalls of said filter media, or traverse axially downwards through said the bottom cap, or both.

3. The filter of claim 1 wherein said diffuser comprises an elongated cylindrical extension.

4. The filter of claim 3 wherein said diffuser includes a tapering sidewall.

5. The filter of claim 1 wherein said diffuser is shaped in a needle-nose or pin-like fashion capable of piercing air pocket within said top portion of said filter media hollow center.

6. The filter of claim 1 wherein said diffuser is integral with said top cap.

7. The filter of claim 1 wherein said filter media includes pleated fiber sheets formed with a hollow center.

8. The filter of claim 1 wherein said filter media includes a porous block formed with a hollow center.

9. A filter for gravity-fed applications comprising: a top cap having fluid ingress apertures and in fluid communication with a filter media; said filter media having a hollow center; a bottom cap attached to said filter media; and a diffuser extending from said top cap to said filter media hollow center and within a top portion of said filter media hollow center; a filter media top end cap such that said filter media is attached to said filter media top end cap at a top end, and said bottom cap at a bottom end; and said filter media top end cap attached to, and in fluid communication with, said top cap; wherein said top cap is substantially submerged by fluid during filtration, and said diffuser pierces any air bubble formed in said hollow center during said filtration.

10. The filter of claim 9 including a sidewall housing shell encompassing said filter media, said sidewall housing shell attached to said filter media top end cap and said bottom cap.

11. The filter of claim 10 wherein said sidewall housing shell includes apertures for fluid egress.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:

(2) FIG. 1 depicts a side view of a filter housing that employs the air lock prevention feature of the present invention;

(3) FIG. 2 depicts a cross-sectional view of the filter housing of FIG. 1;

(4) FIG. 3 depicts a top perspective view of the filter housing of FIG. 1;

(5) FIG. 4 depicts a top perspective, exploded view of the filter housing with a sidewall; and

(6) FIG. 5 depicts a top perspective, exploded view of the filter housing without a sidewall.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

(7) In describing the preferred embodiment of the present invention, reference will be made herein to FIGS. 1-5 of the drawings in which like numerals refer to like features of the invention.

(8) FIG. 1 depicts a side view of a filter housing 10 that may be used to employ the novel air lock prevention feature of the present invention. Like most filter housings, filter housing 10 includes a top cap 12 circumferentially secured or attached to a filter media top end cap 15, which attaches to filter media 22. Filter media top end cap 15 is generally fixed to filter media 22 by a sealant or friction fit. Filter media 22 is shown as pleated fiber sheets, but may also be a carbon block or other suitable media having a hollow center. As a pleated layered material, filter media 22 may also include a pleat pack, an outer fiber sheet, and a drainage layer. Other layered combinations are not excluded, and the present invention will work well with any filter media having a hollow center.

(9) The filter may further include a side housing shell or outer shroud 14. The filter media is terminated circumferentially to a bottom cap 16. In this embodiment, the filter side housing shell has side apertures 18 on shroud 14, which allow for filtered fluid to flow out of filter housing 10; however, side housing apertures 18 need not be configured or shaped as shown, and any aperture configuration that allows for continuous filtered fluid flow into a retaining basin would be sufficient. For a gravity-fed filtration system it is only necessary that an egress aperture be available for filtered water to flow into the retaining basin or storage container (not shown). Such designs normally employ a bottom egress point at bottom cap 16, which could be utilized in the present invention without adverse performance, or side housing apertures as shown.

(10) The present invention is designed to accommodate filter media where fluid permeates radially through the media and may exit the sidewalls or the bottom cap. This directional flow generally causes air to build-up in the hollow center of the filter media. The entrapped air may cause vapor lock, which ultimately degrades or substantially ceases fluid flow.

(11) FIG. 2 depicts a cross-sectional view of filter housing 10 of the present invention. Hollow center 20 centers filter media 22 about an axial center of cylindrical filter 10. In this embodiment, filter media 22 comprises pleated fiber sheets; however, the filter media may also be a solid block media, such as an extruded cylindrical, carbon block. The filter housing is designed so that fluid flows from ingress ports on top cap 12 and filter media top end cap 15 through hollow center 20 of filter media 22, and radially outwards towards side apertures 18. Fluid may also flow outwards through the periphery of bottom cap 16 after having traversed through filter media 22.

(12) Generally, an air pocket or bubble 24 located at the top of filter media 22 will entrap air within hollow center 20 during filtration, and adversely affect fluid flow into hollow center 20. Essentially, during filtration top cap 12 is submersed in fluid, and air is not easily able to escape the filter. To mitigate this air entrapment, top cap 12 includes an elongated surface tension disrupter or diffuser 26 extending from top cap 12 adjacent to, or extending within, hollow center 20, and specifically designed to pierce air pocket 24, preferably terminating just below the topmost portion of filter media 22. Diffuser 26 is preferably shaped in a needle-nose or pin-like fashion capable of piercing air pocket 24, and breaking up the surface tension that holds and forms air pocket 24 into smaller air bubbles that are not capable of retaining a vapor lock. In this manner, any air buildup at air pocket 24 which is formed as a consequence of fluid ingress will no longer adversely affect the fluid flow since the surface tension of the air pocket is destroyed by the surface tension disrupter or diffuser 26.

(13) Diffuser 26 may be a shape other than a needle-nose or pin-like extension. For example, it may be an elongated cylindrical extension, or the like, that by design protrudes into and through a potential air bubble of predetermined size within hollow center 20, and extends within the topmost portion of the filter media. The length of diffuser 26 is such that it is capable of extending within hollow center 20 to pierce an air bubble of predetermined size.

(14) As depicted in the drawings, diffuser 26 is shown preferably shaped as a needle-nose tube, having a generally cylindrical cross-section with a tapering endpoint at the junction of filter media 22. However, the present invention is not limited to any particular cross-sectional shape for the diffuser provided that the selected shape allows the diffuser to pierce the air bubble that forms during fluid flow.

(15) FIG. 3 depicts a top perspective view of the filter housing of the present invention. Top cap 12 is depicted with several water ingress ports or apertures 30a-c. Apertures 30a-c allow fluid to flow into filter 10 when the filter top cap 12 is partially, or more likely, completely submerged in fluid. Fluid enters through these apertures and is directed to the hollow center 20 of filter media 22. Fluid is directed to the side walls of filter media 22, traversing radially outwards from hollow center 20.

(16) FIG. 4 depicts a top perspective, exploded view of the filter housing 10 with a sidewall 14. Sidewall 14 may or may not include apertures. If sidewall 14 does not include apertures, bottom cap 16 would provide apertures for fluid egress. In the embodiment depicted by FIG. 4, sidewall 14 is shown with apertures 18 for fluid egress.

(17) As noted previously, filter media 22 is depicted as a set of pleated sheets; however, it is also possible to use a solid cylindrical filter core, such as a carbon block core, alone or in tandem with a pleated filter media.

(18) FIG. 5 depicts a top perspective, exploded view of the filter housing 10 without a sidewall. Fluid enters hollow center 20 and exits radially through the sides of filter media 22. Also depicted in FIG. 5 are alignment tabs 32 to help secure top cap 12 with diffuser 26 to filter media end cap 15.

(19) The present invention is not limited to the application of a single filter media, or of a filter media consisting solely of pleated sheets. As long as a center core is prone to entrapping air during filtration, a diffuser employed to pierce any air bubble formed during fluid flow would sufficiently mitigate against an air lock condition that would otherwise develop whenever the fluid flow ingress exceeds the air flow egress.

(20) While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.