Tower grain dryer with improved heat reclamation and counter-flow cooling section

Patent metadata

Field	Value
Publication number	US-9863703-B2
Application number	US-201514618810-A
Country	US
Kind code	B2
Filing date	Feb 10, 2015
Priority date	Feb 21, 2014
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A grain drying tower comprises a heater and blower separating a heating plenum and a cooling plenum. The dryer is provided with a heat reclamation/heat recycling system and/or counter-flow cooling to reduce the energy requirements of the tower dryer. The heat reclamation system comprises a chamber external to the outer wall of the tower and which is and located at a point along the drying path. The bottom of the chamber is open to the atmosphere. Hot exhaust air enters the heat reclamation chamber at the top of the chamber and is drawn back into the tower by the blower as the exhaust air exits the open bottom of the chamber. In the counter-flow, the walls defining the grain path of the in the cooling section are not air permeable, and air is drawn into the cooling section through outer wall ducts which are closed at the inner wall. The entering air travels up through heated grain to be warmed, and then enters the plenum through inner wall ducts, which are closed at the outer wall of the tower.

First claim

The invention claimed is:

1. A tower dryer for drying grain, the tower dryer comprising;
an upper drying section comprised of an inner wall and an outer wall surrounding said inner wall; said inner and outer walls both being air permeable; said inner and outer walls, in combination, defining a grain drying flow path; said inner wall defining a heating section central plenum;
a lower cooling section comprised of an inner wall and an outer wall surrounding said inner wall; said cooling section inner and outer walls, in combination, defining a grain cooling flow path which is in communication with, and receives grain from, said grain drying flow path; said inner wall defining a cooling section central plenum; said cooling section inner and outer walls being constructed to enable ambient air external of said tower dryer to be pulled into said cooling section central plenum;
a blower and heater positioned between said cooling section central plenum and said drying section central plenum; said blower and heater being arranged to force heated air into said heating section central plenum;
a heat recovery system comprising an enclosure to trap recyclable air and separate recyclable air from unusable exhaust air and/or ambient air and at least one exhaust air reclamation path having an entrance positioned to receive air that has passed through the outer wall of the upper drying section and into an area enclosed by the enclosure and an exit which is in communication with said cooling section central plenum, wherein said entrance comprises a duct placing the area enclosed by the enclosure in communication with a cooling plenum; whereby, said reclamation path directs heated exhaust air from said drying section, and reintroduces said heated exhaust air into said cooling section central plenum.

2. The tower dryer of claim 1 wherein said cooling section inner and outer walls are comprised of air permeable material.

3. The tower dryer of claim 1 wherein said cooling section inner and outer walls are comprised of air impermeable materials; said tower dryer comprising ducts extending through said grain cooling flow path to place said cooling section central plenum in communication with ambient external air.

4. The tower dryer of claim 3 wherein said ducts comprise a plurality of outer wall ducts extending into said grain cooling path from said cooling section outer wall and being open at said outer wall and a plurality of inner wall ducts extending into said grain cooling path from said cooling section inner wall and being open at said inner wall; said outer wall ducts and said inner wall ducts all being at least partially open at their bottoms; whereby cooling air enters said grain cooling path through an entrance into said outer wall ducts, travels up through downward flowing grain to enter said inner wall ducts, and enters the cooling section central plenum through an exit of said inner wall ducts.

5. The tower dryer of claim 4 wherein the enclosure has an open bottom and wherein the bottom of the enclosure is proximate the level of at least some of the outer wall ducts, whereby exhaust air can be pulled in through the outer wall ducts as cooling air.

6. A tower dryer for drying grain, the tower dryer comprising;
an upper drying section comprised of an inner wall and an outer wall surrounding said inner wall; said inner and outer walls both being air permeable; said inner and outer walls, in combination, defining a grain drying flow path; said inner wall defining a heating section central plenum;
a lower cooling section comprised of an inner wall and an outer wall surrounding said inner wall; said cooling section inner and outer walls, in combination, defining a grain cooling flow path which is communication with, and receives grain from, said grain drying flow path; said inner wall defining a cooling section central plenum; said cooling section inner and outer walls being constructed to enable ambient air external of said tower dryer to be pulled into said cooling section central plenum;
a blower and heater positioned between said cooling section center plenum and said drying section center plenum; said blower and heater being arranged to force heated air into said heating section center plenum;
a heat recovery system comprising at least one exhaust air reclamation path having an entrance positioned to receive air exiting the tower dryer through the drying section and an exit which is in communication with said cooling section central plenum; whereby, said reclamation path directs heated exhaust air from said drying section, and reintroduces said heated exhaust air into said cooling section central plenum;
wherein said cooling section inner and outer walls are comprised of air impermeable materials; said tower dryer comprising ducts extending through said grain cooling flow path to place said cooling section central plenum in communication with ambient external air;
wherein said ducts comprise a plurality of outer wall ducts extending into said grain cooling path from said cooling section outer wall and being open at said outer wall and a plurality of inner wall ducts extending into said grain cooling path from said cooling section inner wall and being open at said inner wall; said outer wall ducts and said inner wall ducts all being at least partially open at their bottoms;
whereby cooling air enters said grain cooling path through an entrance into said outer wall ducts, travels up through downward flowing grain to enter said inner wall ducts, and enters the cooling section central plenum through an exit of said inner wall ducts.

7. The tower dryer of claim 6 wherein said inner wall ducts and said outer wall ducts have sloped upper surfaces defining an angle to the vertical less than the angle of repose for the grain passing through the column.

8. The tower dryer of claim 7 wherein upper surfaces of said inner wall ducts and said outer wall ducts define an inverted V.

9. The tower dryer of claim 8 wherein said inner wall ducts are generally in the shape of an inverted V or are generally diamond shaped.

10. The tower dryer of claim 8 wherein said outer wall ducts are generally in the shape of an inverted V or are generally diamond shaped.

11. The tower dryer of claim 8 wherein either or both of said inner wall ducts and said outer wall ducts comprise a bottom surface that is either perforated or louvered.

12. The tower dryer of claim 6 wherein the heat recovery system includes an enclosure to trap recyclable air and separate recyclable air from unusable exhaust air and/or ambient air.

13. The tower dryer of claim 12 wherein an at least one reclamation path comprises a duct placing the enclosure in communication with a cooling plenum.

14. The tower dryer of claim 12 wherein the enclosure has an open bottom and wherein the bottom of the enclosure is proximate the level of at least some of the outer wall ducts, whereby exhaust air can be pulled in through the outer wall ducts as cooling air.

Assignees

• Gsi Group Llc

Inventors

• Morrison David

Classifications

• F26B21/25

  partly outside the drying enclosure · CPC title

• F26B17/12

  with movement performed solely by gravity {, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft} · CPC title

• F26B23/002 Primary

  recovered from dryer exhaust gases (F26B23/022 takes precedence) · CPC title

• F26B2200/06

  Grains, e.g. cereals, wheat, rice, corn · CPC title

• Y02P70/405

  Cross-Sectional Technologies · mapped topic