Compact high efficiency clam shell heat exchanger
View Patent ↗A clamshell heat exchanger comprises upper and lower clamshell plates assembled together and sealed at the peripheral edges thereof, the assembled plates defining at least three internal passageways communicating in a serpentine configuration. The passageways include an inlet passageway having an inlet port for receipt therethrough of combustion gases, an intermediate passageway and an exhaust passageway having an exit port for the discharge of combustion gases, all such passageways lying generally parallel to each other. In one arrangement of the heat exchanger, the upper and lower clamshell plates define an air gap between the inlet passageway and the intermediate passageway, with the intermediate passageway and the exhaust passageway being joined by a secured flattened portion of the upper and lower clamshell plates. In another arrangement, instead of an air gap, the inlet passageway and the intermediate passageway are also joined by secured flattened portions of the upper and lower clamshell plates. Turbulent flow structure is provided by dimpled surfaces projecting inwardly into the intermediate and exhaust passageways and a longitudinally extending rib projecting into the intermediate passageway. A drain shunt, defined by a generally tubular channel, communicates between the intermediate passageway and the exhaust passageway to allow drainage of condensation from the heat exchanger when the heat exchanger is disposed in any orientation.
1. A furnace heat exchanger comprising:
conductive structure defining at least three passageways for the flow of combustion gases therethrough, said passageways including an inlet passageway, an intermediate passageway communicating with said inlet passageway and an exhaust passageway communicating with said intermediate passageway,
said passageways lying generally parallel to each other with said intermediate passageway being situated between said inlet and said exhaust passageways,
said inlet passageway and said intermediate passageway being separated by an air gap,
said intermediate passageway and said exhaust passageway being joined therebetween by common portions of said conductive structure;
wherein each of said passageways has a cross-section of different area, the cross-sectional area of said inlet passageway being the largest.
2. A heat exchanger according to claim 1 , wherein said intermediate passageway defines a first intermediate passageway, and wherein said conductive structure further defines a second intermediate passageway communicating with said first intermediate passageway and said exhaust passageway and lying generally parallel therebetween.
3. A heat exchanger according to claim 1 , wherein said conductive structure defines a further air gap between said first intermediate passageway and said second intermediate passageway.
4. A heat exchanger according to claim 3 , wherein said second intermediate passageway has a cross-sectional area substantially the same as the cross-sectional area of said first intermediate area.
5. A heat exchanger according to claim 4 , wherein the cross-section of said inlet passageway is generally elliptical, the cross-sections of said first intermediate passageway and said second intermediate passageway are generally rectangular, and the cross-section of said exhaust passageway is generally rectangular but smaller than the cross-sections of the first and second intermediate rectangular passageways.
6. A heat exchanger according to claim 5 , wherein said conductive structure comprises a lower plate member and an upper plate member assembled together and sealed at the peripheral edges, the lower plate and upper plate defining an inlet port at the entrance of the inlet passageway for receipt of combustion gases therethrough and an exit port at the outlet of the exhaust passageway for discharge of combustion gases therethrough.
7. A heat exchanger according to claim 6 , wherein said upper plate and said lower plate define a flattened divider section between said second intermediate passageway and said exhaust passageway.
8. A heat exchanger according to claim 7 , wherein said flattened divider section is secured by at least one fastener.
9. A heat exchanger according to claim 8 , wherein said second intermediate passageway comprises a plurality of dimpled surfaces projecting inwardly into said second intermediate passageway.
10. A heat exchanger according to claim 9 , wherein said exhaust passageway comprises a plurality of dimpled surfaces projecting inwardly into said exhaust passageway.
11. A heat exchanger according to claim 10 , wherein said second intermediate passageway further comprises a longitudinally extending rib extending into said second intermediate passageway.
12. A heat exchanger according to claim 11 , wherein said fastener includes a wall portion projecting into each of said second intermediate passageway and said exhaust passageway for providing a region for turbulent gas flow.
13. A heat exchanger according to claim 1 , wherein said upper plate and lower plate define a drain channel communicating between said intermediate channel and said exhaust channel.
14. A furnace heat exchanger, comprising:
conductive structure defining at least three passageways for the flow of combustion gases therethrough, said passageways including an inlet passageway, an intermediate passageway communicating with said inlet passageway and an exhaust passageway communicating with said intermediate passageway,
said inlet passageway having an inlet port for receipt therethrough of combustion gases,
said exhaust passageway having an exit port for discharge therethrough of combustion gases,
said passageways lying generally parallel to each other with said intermediate passageway being situated between said inlet and said exhaust passageways,
a drain channel defined by a portion of said conductive structure communicating between said exhaust passageway and one of said other passageways;
wherein said conductive structure comprises a lower plate member and an upper plate member assembled together and sealed at the peripheral edges, the lower plate and upper plate defining an inlet port at the entrance of the inlet passageway for receipt of combustion gases therethrough and an exit port at the outlet of the exhaust passageway for discharge of combustion gases therethrough.
15. A heat exchanger according to claim 14 , wherein said upper and lower plate members define said intermediate passageway as a first intermediate passageway, and wherein said upper and lower plate members further define a second intermediate passageway communicating with said first intermediate passageway and said exhaust passageway and lying generally parallel therebetween.
16. A heat exchanger according to claim 15 , wherein said upper and lower plate members define an air gap between said inlet passageway and said first intermediate passageway.
17. A heat exchanger according to claim 16 , wherein said upper and lower plate members define an air gap between said first intermediate member and said second intermediate member.
18. A heat exchanger according to claim 15 , wherein said upper and lower plate members define a flattened secured divider section between at least two of said passageways.
19. A heat exchanger according to claim 18 , wherein said a flattened secured divider section is defined between all of said respective passageways.
20. A furnace heat exchanger, comprising:
first and second clamshell plates assembled together and defining at least three internal passageways communicating in a serpentine configuration,
said passageways including an inlet passageway, an intermediate passageway and an exhaust passageway lying generally parallel to each other,
said first and second clamshell plates defining between at least two of said passageways a flattened divider section secured by at least one fastener having a wall portion projecting into each of said two divided passageways for providing a region within said divided passageways for turbulent gas flow.
21. A heat exchanger according to claim 20 , wherein said flattened divider sections is secured by a plurality of said fasteners.
22. A heat exchanger according to claim 21 , wherein each of said fasteners includes a clinch hole fastener having a hole formed through said first and second clamshell plates, an extruded portion of one of said clamshell plates overlapping a portion of the other of said clamshell plates adjacent said hole.
23. A heat exchanger according to claim 22 , wherein a portion of said clinch hole fasteners defines the wall portion projecting into said passageways.
24. A furnace heat exchanger, comprising:
upper and lower clamshell plates assembled together and defining at least three passageways communicating in a serpentine configuration;
said passageways including an inlet passageway, an intermediate passageway and an exhaust passageway lying generally parallel to each other, and
turbulent flow structure consisting essentially of:
a plurality of dimpled surfaces projecting inwardly of said intermediate passageway and said exhaust passageway, and a longitudinally extending rib projecting into said intermediate passageway.
25. A heat exchanger according to claim 24 , wherein said upper and lower clamshell plates include a fourth passageway defined by a further intermediate passageway, said further intermediate passageway lying between and in communication with said inlet passageway and said intermediate passageway.
26. A heat exchanger according to claim 24 , wherein said turbulent flow structure further consists essentially of a further longitudinally extending rib projecting into said further intermediate passageway.