Air hood

• US 5,206,173 A
• Filed: 06/05/1991
• Issued: 04/27/1993
• Est. Priority Date: 06/05/1991
• Status: Expired due to Term

• Current Assignee: Bedminster International Limited
• Original Assignee: Bedminster Bioconversion Corporation
• Inventors: Finn, Larry J.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): McMahon, Timothy M.
• Application Number:
  US07/710,450
• Time in Patent Office: 692 Days
• Field of Search: 435/287, 435/313, 435/316, 454/251, 454/252, 454/253, 454/185, 454/186, 422/184, 47/17 I, 47/32.1, 202/233, 202/234, 52/199
• US Class Current: 435/290.1
• CPC Class Codes: C05F 17/60 Heating or cooling during the treatment
• CPC Class Codes: C05F 17/964 Constructional parts, e.g. floors, covers or doors
• CPC Class Codes: C05F 17/989 Flow sheets for biological or biochemical treatment
• CPC Class Codes: Y02P 20/145 the feedstock being materials of biological origin
• CPC Class Codes: Y02W 30/40 Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse

Abstract

In a composting process, a heat conductive ventilation hood overlying a compost pile undergoing active composting. The hood is shaped so that process air emanating from the pile contacts the undersurface of the hood while ambient outside cool air is caused to traverse the upper surface of the hood. As a result of this heat exchange arrangement process air is dehumidified while concomitantly the ambient air is heated. The hood is pitched to cause condensate to run down its surface and not to drip. Warmed ambient air is used to heat the composting facility and dehumidified process air and condensate is reused in the composting process.

Claims

1. In a closed facility for the composting of solid waste and sewage sludge, a system comprising:

a hood made of heat-conductive, moisture-impervious material disposed over a compost pile during active composting thereof;

means for directing outside air over exteriorly presented surface portions of said hood to place the outside air in heat exchange relation with heated, moisture laden air emanating from the compost pile impinging on interiorly presented surface portions of said hood;

gutter means for collecting condensate resulting from cooling of the impinging air and duct means for directing the heated outside air into the facility.

2. The system set forth in claim 1, wherein said hood is constructed of a sheet of polyethylene.

3. The system set forth in claim 2, wherein said hood is constructed of two sheets of material disposed to provide an air space therebetween.

4. The system set forth in claim 3, wherein said polyethylene material is suspended over the compost pile by one or more perforated ducts acting as ridgepoles.

5. The system set forth in claim 4, wherein said air ducts are constructed of polyvinyl chloride.

6. The system set forth in claim 4, wherein said perforated ducts act as air conduits for the collection of air emanating from said compost pile.

7. The air recovery system set forth in claim 6, including secondary duct means for recirculating collected air through said compost pile.

8. The system set forth in claim 4, including means for circulating air from outside said facility through said air space to provide a heat exchange relation between the circulating air and air emanating from said compost pile thereby heating the outside air and effecting condensation of moisture contained in air emanating from the compost pile.

9. The system set forth in claim 8, wherein the pitch of the duct-supported material is sufficient to provide non-drippage runoff to condensate.

10. The system set forth in claim 1, including secondary duct means for recirculating dehumidified air through the compost pile.

11. In a closed facility for the composting of solid waste and sewage sludge, a humidity control and heating system comprising:

an air plenum formed between roof portions of said facility and a heat-conductive, moisture-impervious sheet of material underlying said roof portions;

means for causing outside ambient air to traverse said plenum;

a compost pile undergoing active composting disposed beneath said plenum;

means for disbursing air through said compost pile such that air emanating from said compost pile impinges on confronting surface portions of said sheet of material thereby heating the ambient air traversing said plenum and dehumidifying the air impinging on said surface portions and duct means for directing heated outside air into the facility.

12. The system set forth in claim 11, wherein said heat-conductive material comprises a sheet of polyethylene.

13. The system set forth in claim 11, wherein said means for causing the air to traverse said plenum comprises an air recirculating blower.

14. The system set forth in claim 11 wherein said sheet of material is pitched to insure nondrippage runoff of moisture condensing on said sheet of material.

15. The system set forth in claim 14, including gutter means for collecting condensate.

16. The system set forth in claim 11, including secondary duct means for recirculating dehumidified air through the compost pile.

17. The system set forth in claim 11, including duct means for directing heated ambient air into the facility.

18. The system set forth in claim 17, including duct means for using said heated air in the composting process.

19. The air recovery system set forth in claim 11, including valve means for controlling the oxygen content of air being fed to the compost pile by admixing heated ambient air with dehumidified air.