Asymmetric Dimple Tube for Gas Heat
A heat exchanger tube for a gas furnace is provided. The heat exchanger tube may include an inlet, an outlet and one or more asymmetric dimple pairs disposed between the inlet and the outlet. The inlet and the outlet may form a passageway through the heat exchanger tube for receiving a heated combustion gas. Each asymmetric dimple pair may provide a first dimple and an opposing second dimple. The first and second dimples may be configured to at least partially constrict flow of the gas therethrough. Together, the first and second dimples may form an upstream section, a downstream section and a merge point.
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This is a non-provisional U.S. patent application, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/361,797 filed on Jul. 6, 2010, the entirety of which is incorporated by reference herein.
FIELD OF THE DISCLOSUREThe present disclosure generally relates to heat exchangers, and more particularly, to asymmetric dimple tubes for use with heat exchangers as applied to gas furnaces.
BACKGROUND OF THE DISCLOSUREHeat exchangers are commonly known in the art of gas heating and typically used in conjunction with gas furnaces to provide heat to residential and commercial buildings. A typical gas furnace includes a burner which heats gases and supplies the heated gases into an inlet and through a tube of an associated heat exchanger. The tube of a heat exchanger generally provides one or more bends and passes through which the heated flue gases may travel. The heated gases traveling through the bends and passes emit radiation in the form of heat that is transferred through the walls of the tube. One or more fans are used to continuously move air over the surfaces of the heat exchanger tube so as to warm the air using the heat emitted through the heat exchanger tube. Vents and ducts channel the heated air into the interior spaces or rooms within the residential or commercial building. The heated air which eventually cools after some circulation is fed back toward the heat exchanger via the fans to be reheated and recirculated back into the rooms. The flue gases within the heat exchanger never reach the interior spaces of the home or building, and exhausted gases are safely discharged to an exterior of the home or building by induction blowers, or the like.
In residential applications, gas furnaces with such heat exchanger structures have been installed in confined spaces, such as the basement, of the home. In commercial applications, similar furnace and heat exchanger structures have been installed as roof-top units in order to save more valuable floor space. Heat exchangers of both applications share the common goal of transferring as much heat as possible from the heated flue gases into the surrounding air. Moreover, it is well known in the art that the efficiency of a heat exchanger to transfer heat is enhanced by slowing the flow of the heated gases through the passes of the heat exchangers and increasing turbulence thereof.
One existing approach to cause such turbulence uses baffles that are provided within the passes of the heat exchanger tube. Baffles disposed directly in the path of flue gases serve to cause turbulence and hinder the gas flow, and further, to increase the overall transfer of heat to the surrounding air. However, the physical nature of baffles allows substantial vibration and thus noise from within the passes of a particular heat exchanger tube. Furthermore, installing baffles into a heat exchanger tube adds several steps to the manufacturing and assembly thereof, and thus, adds to the overall costs to fabricate same.
Another approach to enhance the efficiency of heat transfer employs the flattening of certain sections of the heat exchanger tube so as to narrow the flow path. While such deformations cause a desired disturbance in the flow of gases therethrough, these deformations also cause inconsistencies in the overall cross-sectional width of the heat exchanger tube. More specifically, flattened sections tend to have wider cross-sections, or cross-sections with widths which extend beyond that of those sections of the tube that are not flattened. Such inconsistencies cause low spots, which in particular arrangements, may trap condensation and complicate any necessary draining.
Still further developments in the prior art provide a heat exchanger or dimple tube 10 having an inlet 12 and an outlet 13, as shown for example in
Each dimple pair 18, 19 consists of two dimples 18, 19 that are indented into opposing surfaces of the second pass 17 to restrict gas flow. Additionally, each dimple 18, 19 is symmetric in that it forms a converging upstream section 20 and a diverging downstream section 21 of equal lengths. The midpoint between the upstream and the downstream section 20, 21, or the merge point 22, has the smallest cross-sectional area, and thus, represents the most constrictive portion of the second pass 17. Such dimple tubes 10 overcome many of the deficiencies associated with heat exchangers with baffles by facilitating assemblies thereof and minimizing fabrication costs. Dimple tubes 10 also overcome many of the aforementioned deficiencies associated with heat exchangers with flattened sections by providing a generally circular cross-section and eliminating low points.
As demonstrated in
Therefore, there is a need for a more efficient heat exchanger which overcomes all of the deficiencies of the prior art. Moreover, there is a need for a heat exchanger with a tube structure that is quieter, increases heat transfer and substantially reduces losses in gas flow as well as losses in overall gas pressure. Furthermore, there is a need for a heat exchanger configuration that is easier and less costly to manufacture or assemble. There is also a need to provide a more efficient heat exchanger that is adaptable to both residential and commercial applications.
SUMMARY OF THE DISCLOSUREIn accordance with one aspect of the disclosure, a heat exchanger tube for a gas furnace is provided. The heat exchanger tube may extend between an inlet and an outlet so as to form a passageway therethrough for receiving a combustion gas. The heat exchanger tube may also include one or more asymmetric dimple pairs disposed between the inlet and the outlet. Each asymmetric dimple pair may include a first dimple and an opposing second dimple. The first and second dimples may be configured to at least partially constrict flow of gas therethrough. Each dimple may be configured to form an upstream section, a downstream section and a merge point.
In accordance with another aspect of the disclosure, another heat exchanger tube for a gas furnace is provided. The heat exchanger tube may include an inlet and an outlet which forms a passageway therethrough for receiving a combustion gas. The heat exchanger tube may also include at least two rows of asymmetric dimples that are disposed along opposing sides of the heat exchanger tube so as to form a plurality of dimple pairs. Each dimple pair may be configured to at least partially constrict flow of gas therethrough. Each dimple pair may also be configured to form an upstream section, a downstream section and a merge point. The upstream section may be shorter in length than the downstream section.
In accordance with yet another aspect of the disclosure, a heating and cooling system is provided. The heating and cooling system may include a ventilation duct, at least one blower or fan as well as at least one heat exchanger tube disposed within the ventilation duct and proximate to the fan. The ventilation duct may be configured to communicate external air with an interior space of a home or building. The fan may be configured to draw the external air through the ventilation duct and toward the interior space. The heat exchanger tube may be configured to receive a heated combustion gas therethrough and heat the external air supplied by the fan. The heat exchanger tube may include a plurality of asymmetric dimple pairs that are at least partially disposed along a length of the heat exchanger tube. Each asymmetric dimple pair may include two opposing dimples that are configured to at least partially constrict flow of gas therethrough. Furthermore, each asymmetric dimple may form an upstream section, a downstream section and a merge point wherein, the upstream section is shorter in length than the downstream section.
These and other aspects of this disclosure will become more readily apparent upon reading the following detailed description when taken in conjunction with the accompanying drawings.
While the present disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to be limited to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling with the spirit and scope of the present disclosure.
DETAILED DESCRIPTIONReferring to the drawings and with particular reference to
As schematically shown in
Referring now to
As shown in the embodiment of
Referring now to
Turning now to
As compared to the analogous illustrations of
Minimizing such separations in gas flow may also serve to minimize dead zones as well as pressure loss, as demonstrated by
Referring now to
Based on the foregoing, it can be seen that the present disclosure may provide a heat exchanger that requires minimal modifications to current methods for manufacturing heat exchangers while overcoming several drawbacks associated with prior art configurations. More specifically, the present disclosure provides more efficient transfer of heat by significantly reducing losses in gas flow as well as minimizing overall pressure loss.
While only certain embodiments have been set forth, alternatives and modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of this disclosure.
Claims
1. A heat exchanger tube for a gas furnace, comprising:
- an inlet and an outlet forming a passageway therethrough for receiving a gas; and
- one or more asymmetric dimple pairs disposed between the inlet and the outlet, each asymmetric dimple pair including a first dimple and an opposing second dimple, the first and second dimples being configured to at least partially constrict flow of the gas therethrough, each asymmetric dimple pair forming an upstream section, a downstream section and a merge point.
2. The heat exchanger tube of claim 1 further comprising at least one bend disposed between to the inlet and the outlet so as to form at least a first pass between the inlet and the bend and a second pass between the bend and the outlet.
3. The heat exchanger tube of claim 2, wherein the asymmetric dimple pairs are disposed along the second pass.
4. The heat exchanger tube of claim 1, wherein the upstream section is substantially shorter than a length of the downstream section.
5. The heat exchanger tube of claim 1, wherein respective lengths of the upstream and downstream sections are at least partially dependent on a cross-sectional diameter of the heat exchanger tube.
6. The heat exchanger tube of claim 1, wherein each of the first and second dimples is formed as an indentation in a surface of the heat exchanger tube.
7. The heat exchanger tube of claim 1, wherein a plurality of asymmetric dimple pairs are linearly disposed along a length of the heat exchanger tube.
8. The heat exchanger tube of claim 1, wherein a plurality of asymmetric dimple pairs are nonlinearly disposed along a length of the heat exchanger tube.
9. The heat exchanger tube of claim 1, wherein a plurality of asymmetric dimple pairs are spirally disposed along a length of the heat exchanger tube.
10. A heat exchanger tube for a gas furnace, comprising:
- an inlet and an outlet forming a passageway therethrough for receiving a gas; and
- at least two rows of asymmetric dimples disposed along opposing sides of the heat exchanger tube so as to form a plurality of dimple pairs, each dimple pair being configured to at least partially constrict flow of the gas therethrough, each dimple pair forming an upstream section, a downstream section and a merge point, the upstream section being shorter in length than the downstream section.
11. The heat exchanger tube of claim 10 further comprising at least one bend disposed between to the inlet and the outlet so as to form at least a first pass between the inlet and the bend and a second pass between the bend and the outlet.
12. The heat exchanger tube of claim 11, wherein the rows of asymmetric dimples are disposed along the second pass.
13. The heat exchanger tube of claim 10, wherein respective lengths of the upstream and downstream sections are at least partially dependent on a cross-sectional diameter of the heat exchanger tube.
14. The heat exchanger tube of claim 10, wherein each asymmetric dimple is formed as an indentation in a surface of the heat exchanger tube.
15. A heating and cooling system, comprising:
- a ventilation duct configured to communicate external air with an interior space;
- at least one fan configured to draw the external air through the ventilation duct and toward the interior space; and
- at least one heat exchanger tube disposed within the ventilation duct and proximate to the fan, the heat exchanger tube being configured to receive a heated combustion gas therethrough and heat the external air supplied by the fan, the heat exchanger tube having a plurality of asymmetric dimple pairs at least partially disposed along a length of the heat exchanger tube, each asymmetric dimple pair having two opposing dimples configured to at least partially constrict flow of the gas therethrough, each asymmetric dimple forming an upstream section, a downstream section and a merge point, the upstream section being shorter in length than the downstream section.
16. The heating and cooling system of claim 15 further being configured as a roof-top unit.
17. The heating and cooling system of claim 15 further comprising a burner disposed proximate to an inlet of the heat exchanger tube.
18. The heating and cooling system of claim 15 further comprising an induction blower disposed proximate to an outlet of the heat exchanger tube.
19. The heating and cooling system of claim 15, wherein the heat exchanger tube includes at least one bend so as to form at least a first pass between the inlet and the bend and a second pass between the bend and the outlet.
20. The heating and cooling system of claim 19, wherein the asymmetric dimple pairs are distributed along the second pass.
Type: Application
Filed: Jun 21, 2011
Publication Date: Jan 12, 2012
Applicant: Carrier Corporation (Farmington, CT)
Inventors: Yu Guo (Pudong), Brian D. Videto (Cortland, NY), Lei Yu (Pudong)
Application Number: 13/165,315
International Classification: F28F 13/00 (20060101); F28F 1/00 (20060101);