US3941698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Grit selector
Assignee: Smith and Loveless Inc
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Filing: 1975-05-08
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Granted: 1976-03-02
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Expires: 1995-05-08
Abstract
Abstract A grit selector having an upper settling chamber and a lower grit storage chamber. The settling chamber communicates with the storage chamber through a relatively small opening in a flat transition surface therebetween. Rotating paddles critically positioned within the settling chamber cause the flow of liquid entering the settling chamber adjacent the outer periphery to rotate about the chamber in a forced vortex having upward spiral flow. Settled grit attaches to the transition surface at the settling chamber perimeter before one revolution. The spiral flow urges the grit across the transition surface towards the opening while the organics are lifted upward and back into the flow. The grit drops through the opening into the grit storage chamber and the organics are carried out of the settling chamber through an outlet passageway. A unique air scour arrangement is provided to remove any organic material which has settled in the grit storage chamber and an air lift is provided to remove the settled grit from the grit storage chamber.
Inventors
- 👤 Frank G. Weis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:23
CPC Classifications
B; B01; B01D; B01D21/00; B01D21/0087; B01D21/24; B01D21/245; B01D21/26; B01D21/267; B01D21/30; B01D21/34
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
238 words
Apparatus for separating out grit from liquid sewage while retaining organic solids therein, comprising: a cylindrical settling chamber; a cylindrical grit storage chamber, having a smaller diameter than said settling chamber, disposed immediately below said settling chamber; a substantially flat transition surface separating said settling chamber and said storage chamber, said transition surface having a centrally disposed opening therethrough permitting communication between said settling chamber and said storage chamber; inlet means for introducing liquid sewage into an upper portion of said settling chamber along the outer periphery thereof, outlet means for removing grit free liquid from an upper portion of said settling chamber along the outer periphery thereof, said outlet means being spaced from said inlet means by a distance equal to a substantial portion of the circumference of said settling chamber in the direction of liquid flow; said liquid flow having a flow velocity in the laminar range; and paddle means mounted within said settling chamber for rotation about a substantially verticla axis, said paddle means being positioned a short distance above said transition surface opening and rotated at a sufficient rate for causing the liquid within said settling chamber to rotate as a forced vortex resulting in an upward spiral flow which urges the settled particles across said transition surface toward said opening and causes said grit to fall through said opening into said storage chamber and said organic particles to rise in said spiral flow.
Claim 2
Dependent Claim
238 words
Apparatus for separating out grit from liquid sewage while retaining organic solids therein, comprising: a cylindrical settling chamber; a cylindrical grit storage chamber, having a smaller diameter than said settling chamber, disposed immediately below said settling chamber; a substantially flat transition surface separating said settling chamber and said storage chamber, said transition surface having a centrally disposed opening therethrough permitting communication between said settling chamber and said storage chamber; inlet means for introducing liquid sewage into an upper portion of said settling chamber along the outer periphery thereof, outlet means for removing grit free liquid from an upper portion of said settling chamber along the outer periphery thereof, said outlet means being spaced from said inlet means by a distance equal to a substantial portion of the circumference of said settling chamber in the direction of liquid flow; said liquid flow having a flow velocity in the laminar range; and paddle means mounted within said settling chamber for rotation about a substantially verticla axis, said paddle means being positioned a short distance above said transition surface opening and rotated at a sufficient rate for causing the liquid within said settling chamber to rotate as a forced vortex resulting in an upward spiral flow which urges the settled particles across said transition surface toward said opening and causes said grit to fall through said opening into said storage chamber and said organic particles to rise in said spiral flow.
Claim 3
Dependent Claim
37 words
Apparatus as defined in claim 1 further including a substantially vertical air lift tube means extending from said settling chamber through said opening into said storage chamber for removing grit from the bottom of said storage chamber.
Claim 4
Dependent Claim
53 words
Apparatus as defined in claim 2 further including a plurality of substantially horizontal air scour arms extending radially outward from said air lift tube means for providing air scour through openings formed therein to the grit settled on the bottom of said storage chamber so as to separate organic material from the grit.
Claim 5
Dependent Claim
66 words
Apparatus as defined in claim 3 further including an air lift chamber formed concentrically around said air lift tube means within said storage chamber, said air lift chamber being in communication with a source of pressurized air, and a plurality of circumferentially spaced openings passing through said air lift tube means permitting pressurized air from said air lift chamber to pass into said air lift tube.
Claim 6
Dependent Claim
44 words
Apparatus as defined in claim 3 further including an air scour chamber formed concentrically around said air lift tube means within said storage chamber, said air scour chamber being in fluid communication with a source of pressurized air and with said air scour arms.
Claim 7
Dependent Claim
27 words
Apparatus as defined in claim 2 wherein said paddle means is secured to a sleeve mounted concentric with and for rotation about said air lift tube means.
Claim 8
Dependent Claim
25 words
Apparatus as defined in claim 5 wherein said air scour arms contact the side wall of said settling chamber to steady said air lift tube.
Claim 9
Dependent Claim
30 words
Apparatus as defined in claim 7 wherein said storage chamber has a centrally located grit settling area defined within a fill area around the lower periphery of said storage chamber.
Claim 10
Dependent Claim
50 words
Apparatus as defined in claim 6 wherein said transition surface includes a transition plate positioned in covering relationship to said storage chamber, said transition plate having a centrally disposed opening to receive said sleeve therethrough and define an annular opening therebetween for passage of said grit into said storage chamber.
Claim 11
Dependent Claim
81 words
Apparatus as defined in claim 9 wherein the distance (H) measured in feet from the center line of the middle of said paddle means to said transition surface is in the range H = 3/4 to 7/8 ##EQU4## where X = height of water in said settling chamber at maximum flow measured in feet, Q = maximum flow rate through said settling chamber measured in cubic feet per second, and B = the width of said outlet means measured in feet.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |