IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0263838
(2002-10-03)
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발명자
/ 주소 |
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인용정보 |
피인용 횟수 :
20 인용 특허 :
4 |
초록
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A vacuum filtration apparatus (900) for detecting microorganisms and particulates in liquid samples. The apparatus includes a base (901), an absorbent pad (991), a filter (990), a funnel (930), and a lid (960). The funnel is releasably attached to the base, and may contain an integral flexible seal
A vacuum filtration apparatus (900) for detecting microorganisms and particulates in liquid samples. The apparatus includes a base (901), an absorbent pad (991), a filter (990), a funnel (930), and a lid (960). The funnel is releasably attached to the base, and may contain an integral flexible seal for releasably sealing the filter to the base. The outer wall of the lid may be segmented to make it flexible, this flexibility allows it to be releasably attached to the funnel or the base. The apparatus is designed so that any funnel will fit any base, and any lid will fit any base or any funnel when all parts are manufactured to normal tolerances. The apparatus may be configured to to keep the filter wrinkle free in both the dry and wet states.
대표청구항
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1. A vacuum filtration apparatus comprising:a base including a filter seal surface and a side wall, surrounding a central axis of said base, said sidewall including an inner surface and an outer surface with the inner surface of said side wall extending in a substantially straight line upward from a
1. A vacuum filtration apparatus comprising:a base including a filter seal surface and a side wall, surrounding a central axis of said base, said sidewall including an inner surface and an outer surface with the inner surface of said side wall extending in a substantially straight line upward from an outer periphery of said filter seal surface to the top of said base, with the angle between said inner surface and the central axis of said base being greater than or equal to zero degrees, and with said base being made of a material that is sufficiently pliable to allow said side wall to be deflected outward. a filter means, having an upstream surface, a downstream surface and an outer periphery with the outer periphery of said filter means sealed to said filter seal surface to prevent the flow of unfiltered liquid between said filter seal surface and the downstream surface of said filter means, a funnel capable of holding un-filtered liquid therein, with the shape of a bottom outside surface of said funnel matching the shape of said inner surface of said base, with the bottom outside surface of said funnel containing a chamfer, with the maximum outside radius of said chamfer being less than or equal to the corresponding inside radius of a bottom of said side wall of said base, said chamfer allowing alignment of said funnel with respect to said base before the funnel is fully inserted into the base, with the bottom of said funnel inserted into said base, with the portion of an outer surface of said funnel above said chamfer that is inserted into said base extending upward from a top of said chamfer in a substantially straight line, with the angle between said outer surface of said funnel above said chamfer that is inserted into said base and the central axis of said funnel being greater than zero, with at least a portion of the outer surface of said funnel above said chamfer that is inserted into said base having an outside radius that is greater than the inside radius at the top of said side wall of said base, with said funnel made from a material that is sufficiently more rigid than the material of the base to cause the inner surface of said side wall of said base to deflect outward as the portion of said funnel above said chamfer is inserted into said base, and to continue deflecting outward until said funnel is fully inserted into said base, and to remain deflected outward for as long as said funnel is inserted into said base, thereby releasably attaching said funnel to said base with an interference fit between the deflected inner surface of said side wall of said base and at least a portion of the outer surface of the funnel above said chamfer that is inserted into said base, with a sufficient force to prevent accidental disengagement of the funnel from the base, with neither the inner surface of said side wall of said base or the outer surface of the portion of said funnel that is inserted into said base containing any grooves or protrusions that interlock with each other, said base further containing an outlet port in fluid flow communication with the downstream surface of said filter means. 2. The vacuum filtration apparatus of claim 1 wherein the angle between said inner surface of said side wall of said base and the central axis of said base, is less than the angle between said outer surface of said funnel above said chamfer that is inserted into said base and the central axis of said funnel.3. The vacuum filtration apparatus of claim 2 wherein the angle between said outer surface of said funnel above said chamfer that is inserted into said base is equal to, or greater than, the minimum deflected angle of said side wall of said base, thereby causing the entire surface area of said outer wall of said funnel above said chamfer that is inserted into said base to contact the inner surface of said side wall of said base, thereby maximizing the strength of said interference fit.4. The vacuum filtration apparatus of claim 3 wherein the inner surface of said side wall of said base is textured to maximize the interference fit between said funnel and said base.5. The vacuum filtration apparatus of claim 3 wherein the outer surface of the funnel above said chamfer that if inserted into said base is textured to maximize the interference fit between said funnel and said base.6. The vacuum filtration apparatus of claim 1 wherein the bottom surface of said funnel contacts the outer periphery of said filter means above said filter seal surface of said base when the funnel is fully inserted into the base.7. The vacuum filtration apparatus of claim 6 wherein said filter means is releasably sealed to said filter seal surface of said base by compressing the outer periphery of said filter means between said filter seal surface of said base and said bottom surface of said funnel.8. The vacuum filtration apparatus of claim 1 wherein a pliable sealing means is compressed between the bottom surface of said funnel and the outer periphery of the upstream surface of said filter when the funnel is fully inserted into the base, thereby releasably sealing said filter means to said filter seal surface of said base by compressing the outer periphery of said filter means between said filter seal surface of said base and said pliable scaling means.9. The vacuum filtration apparatus of claim 8 wherein said pliable sealing means is an integral part of said funnel.10. The vacuum filtration apparatus of claim 1 wherein said filter means is non-releasably sealed to said filter seal surface of said base.11. The vacuum filtration apparatus of claim 10 wherein said non-releasable seal is a heat seal.12. The vacuum filtration apparatus of claim 10 wherein said non-releasable seal is an ultra-sonic seal.13. The vacuum filtration apparatus of claim 1 wherein said base further contains a pad well disposed inside of, and below said filter seal surface of said base, and wherein an absorbent pad is disposed in said pad well.14. The vacuum filtration apparatus of claim 13 wherein the dry thickness of said absorbent pad is sufficiently greater than the height of said pad well to keep said filter means in tension and wrinkle free when both the filter means and the absorbent pad are dry,and wherein the thickness of the absorbent pad is sufficiently greater than the height of said pad well, and wherein the thickness of the absorbent pad is sufficiently thicker than the thickness of the filter means, so that as the absorbent pad swells in thickness after being wetted by the liquid being filtered, the top surface of the absorbent pad will swell a sufficient amount above the top of the pad well to keep the filter means in tension and wrinkle free as the filter means expands in diameter after the filter means has been wetted by the liquid being filtered. 15. The vacuum filtration apparatus of claim 1 wherein the portion of said funnel above said chamfer that is inserted into said base has a nominal outside radius that is sufficiently greater than the corresponding nominal inside radius of said side well of said base to allow the funnel to be releasably attached to the base with a sufficient force to prevent accidental disengagement of the funnel from the base for all outside radii of the funnel and for all inside radii of the base within a normal production range of dimensional tolerances of both the funnel and the base.16. The vacuum filtration apparatus of claim 1 wherein said funnel contains a funnel stop in the form of an annular projection that projects from the outer wall of said funnel, with the distance between the bottom of said funnel stop and the top of said side wall of said base being greater than or equal to zero when said funnel is fully inserted into said base, said funnel stop acting as a dust cap to prevent contamination of the seal region between the funnel and the base.17. The vacuum filtration apparatus of claim 1 wherein said funnel and said base are circular in shape, and wherein said funnel contains one or more lid clamp tabs protruding from the upper portion of the outside wall of said funnel above the portion of the funnel that is inserted into said base, with the one or more lid clamp tabs containing a sloped surface that tapers outward from the top of the one or more lid clamp tabs to the bottom portion of the one or more lid clamp tabs, so that the minimum diameter of the sloped surface of the one or more lid clamp tabs occurs at the top of the sloped surface of the one or more lid clamp tabs, and so that the maximum diameter of the sloped surface of the one or more lid clamp tabs occurs at the bottom of the sloped surface of the one or more lid clamp tabs.18. The vacuum filtration apparatus of claim 17 wherein said vacuum filtration apparatus further includes a lid, having an outer wall with a substantially cylindrical inner surface with the height of the substantially cylindrical inner surface being greater than the distance between the bottom edge of the sloped surface of the one or more lid clamp tabs of the funnel and the top wall of the funnel,with the lid further including a plurality of slots in the outer wall, with each slot creating a gap in the bottom surface of the outer wall, with the height of the slots being less than or equal to the height of the substantially cylindrical inner surface of the outer wall, with the slots dividing the outer wall into a plurality of segments, thereby allowing the outer wall to flex, with the diameter of the substantially cylindrical inner surface of the outer wall of the lid being greater than or equal to the diameter of the top outside edge of the funnel, and with the diameter of said substantially cylindrical inner surface of the outer wall of the lid being sufficiently less than the maximum outside diameter of the sloped surface of the one or more lid clamp tabs of the funnel when the outer wall of the lid is in its un-flexed state, for all values of the diameter of the substantially cylindrical inner surface of the outer wall of the lid within a normal manufacturing tolerance range around its nominal value, and for all values of the diameter of the top outside edge of the funnel within a normal manufacturing tolerance range around its nominal value, and for all values of the maximum outside diameter of the sloped surface of the one or more lid clamp tabs of the funnel within a normal manufacturing tolerance range around its nominal value, with the number of slots being sufficient to allow the outer wall to flex a sufficient amount when the lid is made from a rigid material, so that the flexing of the outer wall of the lid allows the lid to be easily pressed onto the top of the funnel without the need to rotate the lid with respect to the funnel so that as the bottom inside edge of the substantially cylindrical inner surface of the outer wall of the lid is pushed down onto the sloped surface of the one or more lid clamp tabs, the bottom inside edge of the outer wall will slide over the sloped surface of the one or more lid clamp tabs until the lid is fully seated onto the funnel with the bottom inside edge of the lid disposed below the bottom of the sloped surface of the one or more lid clamp tabs, thereby causing the segments of the substantially cylindrical inner surface of the outer wall of the lid that contact the one or more lid clamp tabs of the funnel to expand outward and to remain expanded outward for as long as the lid is pressed onto the funnel, thereby releasably attaching the lid to the funnel with an interference fit between the bottom portion of the one or more lid clamp tabs of the funnel and the segments of the inner surface of the outer wall of the lid that contact the bottom portion of the one or more lid clamp tabs, with the interference fit being sufficient to prevent the lid from accidentally disengaging from the funnel, while also allowing the lid to be easily removed from the funnel with one hand by lifting the lid from the funnel without the need to rotate the lid with respect to the funnel, thereby causing the outer wall of the lid to return to its un-expanded state. 19. The vacuum filtration apparatus of claim 1 wherein said base contains three or more filter centering tabs that protrude upward from said filter seal surface, and inward from said inner surface of said side wall.20. A vacuum filtration apparatus comprising:a base including a filter seal surface and a side wall, surrounding a central axis of said base, said sidewall including an inner surface and an outer surface with the inner surface of said side wall extending in a substantially straight line upward from an outer periphery of said filter seal surface to the top of said base, with the angle between said inner surface and the central axis of said base being greater than or equal to zero degrees, and with said base being made of a material that is sufficiently pliable to allow said side wall to be deflected outward. a filter means, having an upsteam surface, a downstream surface and an outer peripery and an outer periphery with the outer periphery of said filter means sealed to said filter seal surface to prevent the flow of unfiltered liquid between said filter seal surface and the downstream surface of said filter means, a funnel capable of holding un-filtered liquid therein, with the shape of a bottom outside surface of said funnel matching the shape of said inner surface of said base, with the bottom outside surface of said funnel containing a step, with the maximum outside radius of said step being less than or equal to the corresponding inside radius of a bottom of said side wall of said base, said step allowing alignment of said funnel with respect to said base before the funnel is fully inserted into the base, with the bottom of said funnel inserted into said base, with the portion of a outer surface of said funnel above said step that is inserted into said base extending upward from a top of said step in a substantially straight line, with the angle between said outer surface of said funnel above said step that is inserted into said base and the central axis of said funnel being greater than zero, with at least a portion of the outer surface of said funnel above said step that is inserted into said base having an outside radius that is greater than the inside radius at the top of said side wall of said base, with said funnel made from a material that is sufficiently more rigid than the material of the base to cause the inner surface of said side wall of said base to deflect outward as the portion of said funnel above said step is inserted into said base, and to continue deflecting outward until said funnel is fully inserted into said base, and to remain deflected outward for as long as said funnel is inserted into said base, thereby releasably attaching said funnel to said base with an interference fit between the deflected inner surface of said side wall of said base and at least a portion of the outer surface of the funnel above said step that is inserted into said base, with a sufficient force to prevent accidental disengagement of the funnel from the base, with neither the inner surface of said side wall of said base or the outer surface of the portion of said funnel that is inserted into said base containing any grooves or protrusions that interlock with each other, said base further containing an outlet port in fluid flow communication with the downstream surface of said filter means. 21. The vacuum filtration apparatus of claim 20 wherein said funnel contains a chamfer located at the top of said step, thereby providing a gradual transition from the smaller outside radius of said step to the larger outside radius of the funnel disposed directly above said step.22. The vacuum filtration apparatus of claim 20 wherein the angle between said inner surface of said side wall of said base and the central axis of said base, is less than the angle between said outer surface of said funnel above said step that is inserted into said base and the central axis of said funnel.23. The vacuum filtration apparatus of claim 22 wherein the angle between said outer surface of said funnel above said step that is inserted into said base is equal to, or greater than, the minimum deflected angle of said side wall of said base, thereby causing the entire surface area of said outer wall of said funnel above said step that is inserted into said base to contact the inner surface of said side wall of said base, thereby maximizing the strength of said interference fit.24. The vacuum filtration apparatus of claim 20 wherein the bottom surface of said funnel contacts the outer periphery of said filter means above said filter seal surface of said base when the funnel is fully inserted into the base.25. The vacuum filtration apparatus of claim 24 wherein said filter means is releasably sealed to said filter seal surface of said base by compressing the outer periphery of said filter means between said filter seal surface of said base and said bottom surface of said funnel.26. The vacuum filtration apparatus of claim 20 wherein a pliable sealing means is compressed between the bottom surface of said funnel and the outer periphery of the upstream surface of said filter when the funnel is fully inserted into the base, thereby releasably sealing said filter means to said filter seal surface of said base by compressing the outer periphery of said filter means between said filter seal surface of said base and said pliable sealing means.27. The vacuum filtration apparatus of claim 26 wherein said pliable sealing means is an integral part of said funnel.28. The vacuum filtration apparatus of claim 20 wherein said filter means is non-releasably sealed to said filter seal surface of said base.29. The vacuum filtration apparatus of claim 20 wherein said base further contains a pad well disposed inside of, and below said filter seal surface of said base, and wherein an absorbent pad is disposed in said pad well.30. The vacuum filtration apparatus of claim 29 wherein the dry thickness of said absorbent pad is sufficiently greater than the height of said pad well to keep said filter means in tension and wrinkle free when both the filter means and the absorbent pad are dry,and wherein the thickness of the absorbent pad is sufficiently greater than the height of said pad well, and wherein the thickness of the absorbent pad is sufficiently thicker than the thickness of the filter means, so that as the absorbent pad swells in thickness after being wetted by the liquid being filtered, the top surface of the absorbent sloped surface of the one or more lid clamp tabs occurs at the top of the sloped surface of the one of more lid clamp tabs, and so that the maximum diameter of the sloped surface of the one or more lid clamp tabs occurs at the bottom of the sloped surface of the one or more lid clamp tabs. with said vacuum filtration apparatus further including a lid having an outer wall with a substantially cylindrical inner surface with the height of the substantially cylindrical inner surface being greater than the distance between the bottom edge of the sloped surface of the one or more lid clamp tabs of the funnel and the top wall of the funnel, with the lid further including a plurality of slots in the outer wall, with each slot creating a gap in the bottom surface of the outer wall, with the height of the slots being less than or equal to the height of the substantially cylindrical inner surface of the outer wall, with the slots dividing the outer wall into a plurality of segments, thereby allowing the outer wall to flex, with the diameter of the substantially cylindrical inner surface of the outer wall of the lid being greater than or equal to the diameter of the top outside edge of the funnel, and with the diameter of said substantially cylindrical inner surface of the outer wall of the lid being sufficiently less than the maximum outside diameter of the sloped surface of the one or more lid clamp tabs of the funnel when the outer wall of the lid is in its un-flexed state, for all values of the diameter of the substantially cylindrical inner surface of the outer wall of the lid within a normal manufacturing tolerance range around its nominal value, and for all values of the diameter of the top outside edge of the funnel within a normal manufacturing tolerance range around its nominal value, and for all values of the maximum outside diameter of the sloped surface of the one or more lid clamp tabs of the funnel within a normal manufacturing tolerance range around its nominal value, with the number of slots being sufficient to allow the outer wall to flex a sufficient amount when the lid is made from a rigid material, so that the flexing of the outer wall of the lid allows the lid to be easily pressed onto the top of the funnel without the need to rotate the lid with respect to the funnel so that as the bottom inside edge of the pad will swell a sufficient amount above the top of the pad well to keep the filter means in tension and wrinkle free as the filter means expands in diameter after the filter means has been wetted by the liquid being filtered. 31. The vacuum filtration apparatus of claim 20 wherein the portion of said funnel above said step that is inserted into said base has a nominal outside radius that is sufficiently greater than the nominal inside radius of said side wall of said base to allow the funnel to be releasably attached to the base with a sufficient force to prevent accidental disengagement of the funnel from the base for all outside radii of the funnel and for all inside radii of the base within a normal production range of dimensional tolerances of both the funnel and the base.32. The vacuum filtration apparatus of claim 20 wherein said base contains three or more filter centering tabs that protrude upward from said filter seal surface, and inward from said inner surface of said side wall.33. A vacuum filtration apparatus comprising:a base containing an outlet port capable of being adapted to a vacuum source, a funnel with an open top attached to the base, a filter support means disposed upstream of the outlet port, a filter means disposed upstream of the filter support means, said filter means being sealed to the vacuum filtration apparatus, thereby preventing un-filtered liquid from bypassing the filter means, thereby preventing the flow of un-filtered liquid through the outlet port, with the interior of the funnel capable of holding un-filtered liquid upstream of said filter means, with said funnel containing one or more lid clamp tabs protruding from the upper portion of the outside wall of said funnel, with the one or more lid clamp tabs including a sloped surface that tapers outward from a top of the one or more lid clamp tabs to a bottom portion of the one or more lid clamp tabs, so that the minimum diameter of the substantially cylindrical inner surface of the outer wall of the lid is pushed down onto the sloped surface of the one or more lid clamp tabs, the bottom inside edge of the outer wall will slide over the sloped surface of the one or more lid clamp tabs until the lid is fully seated onto the funnel with the bottom inside edge of the lid disposed below the bottom of the sloped surface of the one or more lid clamp tabs, thereby causing the segments of the substantially cylindrical inner surface of the outer wall of the lid that contact the one or more lid clamp tabs of the funnel to expand outward and to remain expanded outward for as long as the lid is pressed onto the funnel, thereby releasably attaching the lid to the funnel with an interference fit between the bottom portion of the one or more lid clamp tabs of the funnel and the segments of the inner surface of the outer wall of the lid that contact the bottom portion of the one or more lid clamp tabs, with the interference fit being sufficient to prevent the lid from accidentally disengaging from the funnel, while also allowing the lid to be easily removed front the funnel with one hand by lifting the lid from the funnel without the need to rotate the lid with respect to the funnel, thereby causing the outer wall of the lid to return to its un-expanded state. 34. A vacuum filtration apparatus comprising:a base including an outlet port capable of being adapted to a vacuum source, a filter seal surface disposed above said outlet port, and a pad well, said pad well containing a substantially vertical side wall and a bottom wall, with the boundary of the top of a side wall of the pad well being coincident with the inner boundary of the filter seal surface, with the bottom surface of the pad well being substantially parallel to the filter seal surface, and disposed entirely below the filter seal surface, an absorbent pad disposed in said pad well, with the downstream surface of said absorbent pad resting directly on the bottom surface of the pad well, a filter means, with the downstream surface of the outer periphery of the filter means in direct contact with the filter seal surface of the base, with the outer periphery of the filter means sealed to the vacuum filtration apparatus to prevent the flow of un-filtered liquid between the filter seal surface of the base and the downstream surface of the outer periphery of the filter means, with at least a portion of the downstream surface of the filter means disposed inside of the filter seal surface of the base resting on the top surface of the absorbent pad, a funnel with an open top attached to the base, said funnel forming a reservoir capable of holding un-filtered liquid upstream of the filter means, wherein the dry thickness of said absorbent pad is sufficiently greater than the height of said pad well thereby keeping said filter means in tension and wrinkle free when both the filter means and the absorbent pad are dry, and wherein the thickness of the absorbent pad is sufficiently greater than the height of said pad well, and wherein the thickness of the absorbent pad is sufficiently thicker than the thickness of the filter means, so that as the absorbent pad swells in thickness after being wetted by the liquid being filtered, the top surface of the absorbent pad will swell a sufficient amount above the top of the pad well to keep the filter means in tension and wrinkle free as the filter means expands in diameter after the filter means has been wetted by the liquid being filtered.
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