INTERNAL HEAT EXCHANGER

Abstract

An internal heat exchanger includes an inner tube for a flow of a first fluid; an outer tube that is coaxial with the inner tube; a passageway between the inner tube and the outer tube for a flow of a second fluid; and, a flow enhancer inside the inner tube and configured to divert the flow of fluid in the inner tube along a wall of the inner tube.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of international patent application PCT/US2013/054449, filed Aug. 11, 2013 which designates the United States and claims priority from United States Provisional Application No. 61/681,668 filed Aug. 10, 2012. The present continuation application claims priority to each of the above applications and incorporates herein the entire contents thereof by reference.

FIELD OF THE INVENTION

The present disclosure relates to an internal heat exchanger, and more particularly to a double tube internal heat exchanger for a vehicle.

BACKGROUND OF THE INVENTION

Internal heat exchanger assemblies are now being used on vehicle air conditioning systems to improve performance and system efficiency. Efficiency and performance gains are achieved by the use of a coaxial heat exchanger where the liquid refrigerant is flowed around the outside of the suction tube.

Heat is transferred from the liquid to the suction line which increases sub-cooling in the liquid line.

SUMMARY OF THE INVENTION

The present invention includes an internal heat exchanger for a vehicle with improved suction line flow. The internal heat exchanger has an inner tube and an outer tube. The inner tube and outer tube are coaxial with one another. A flow enhancer is disposed within the inner tube to divert flow of fluid towards an outer wall of the inner tube. The flow diversion aids in the transfer of heat to the outer wall thereby improving the efficiency of the heat exchanger.

The flow enhancer may be an elongate shape and may be formed, for example, from an extrusion process. The flow enhancer can be shaped so as to divert flow towards the outer wall of the inner tube while blocking the flow of fluid from the middle of the tube. For example, the flow enhancer may be an elongate member having a generally cylindrical central portion and a plurality of radially extending longitudinal fins.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings wherein:

FIG. 1 is a spring internal heat exchanger;

FIG. 2A shows a view of a multi-channel internal heat exchanger;

FIG. 2B shows a section along line 2B-2B of FIG. 2A;

FIG. 2C shows a view of a multi-channel internal heat exchanger;

FIG. 3A is an embodiment of a flow enhancer in accordance with aspects of the invention;

FIG. 3B is an embodiment of a suction tube;

FIG. 3C is an embodiment of an assembly of the flow enhancer and suction tube of FIGS. 3A and 3B;

FIG. 4A is an embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a channel internal heat exchanger;

FIG. 4B is an embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a spring internal heat exchanger;

FIG. 5A is an embodiment of a spring internal heat exchanger having a flow enhancer; and,

FIG. 5B is an embodiment of a channel internal heat exchanger having a flow enhancer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 is a spring internal heat exchanger 10. FIGS. 2A to 2C show various views of a channel heat exchanger 20. Both heat exchangers (10, 20) include an inner tube 30 and an outer tube 32 that are coaxial with one another. The inner tube 30 is the return line (also referred to as a “suction line”) of a refrigeration system. The inner tube 30 and outer tube 32 are separated by a passageway. In the spring heat exchanger 20, the inner tube 30 and outer tube 32 are separated by a spring 34 forming a helical passageway between the tubes. In the channel heat exchanger 30, the inner tube 30 and outer tube 32 are separated by a plurality of ribs 36 that form one or more channel-shaped passageways 38.

Referring now to FIGS. 3A to 3C, the heat exchangers (10, 20) are shown with a flow enhancer 50. The flow enhancer 50 may be an elongate member. The elongate member may be formed by an extrusion process. As shown best in FIG. 3A, the flow enhancer 50 has a central portion 52 that extends axially and a plurality of radial members 52 (for example, ribs) that extend along the axial length of the flow enhancer. In one embodiment, at least one radial member can be a continuous fin that extends along the full axial length of the flow enhancer. Additionally or alternatively, the flow enhancer may include a plurality of fins that extend along a portion of an axial length of the flow enhancer (for example, less than the full axial length of the flow enhancer).

The central portion 52 may have a substantially circular cross-section. The flow enhancer 50 is assembled with the inner tube 30 such that the flow enhancer 50 and inner tube 30 are coaxial with one another. The outer portions 54 of the radial members 52 may be in contact with the inner tube 30, as shown in FIG. 3C.

The flow enhancer 50, and in particular, the central portion 52, blocks flow in the center of the inner tube 30 (suction tube) and diverts or forces the flow against a wall 51 of the tube 30. The central portion 52 and radial members 54 can be configured to minimize pressure drop across the internal heat exchanger. The flow enhancer may be formed from a composite material that may be bendable with the inner and outer tubes. In one embodiment, the flow enhancer is constructed from a composite material that does not substantially affect heat transfer.

Referring still to FIGS. 3A to 3C, the material can, for example, also be composite plastic, nylon or any metal such as aluminum, copper or a combination of metal and plastic. The rib design may or may not be continuous.

FIG. 4A is an embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a channel internal heat exchanger wherein the rib edge is in contact with the suction tube inner diameter. FIG. 4B is an embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a spring internal heat exchanger wherein the rib edge is in contact with the suction tube inner diameter.

FIG. 5A is an embodiment of a spring internal heat exchanger having a flow enhancer and FIG. 5B is an embodiment of a channel internal heat exchanger having a flow enhancer.

It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An internal heat exchanger comprising:

an inner tube for a first flow of a first fluid;

an outer tube;

said inner tube and said outer tube being coaxial to each other;

said inner tube and said outer tube conjointly defining a passageway therebetween for a second flow of a second fluid;

said inner tube having an inner tube wall; and,

a flow enhancer arranged inside said inner tube and configured to divert said first flow of said first fluid along said inner tube wall.

2. The internal heat exchanger of claim 1, wherein said flow enhancer is an elongate member.

3. The internal heat exchanger of claim 1, wherein said flow enhancer includes a central portion and a plurality of radial members extending from said central portion.

4. The internal heat exchanger of claim 3, wherein said central portion has a cylindrical shape.

5. The internal heat exchanger of claim 3, wherein said radial members each have an outer portion in contact with said inner tube.

6. The internal heat exchanger of claim 1 further comprising a spring arranged between said inner tube and said outer tube.

7. The internal heat exchanger of claim 1 further comprising a plurality of longitudinal channels between said inner tube and said outer tube.

8. The internal heat exchanger of claim 1, wherein said flow enhancer and said inner tube wall conjointly define a plurality of channels therebetween.

9. A flow enhancer for an internal heat exchanger comprising:

an axially extending central body; and,

a plurality of radial members extending from said central body.

10. The flow enhancer of claim 9, wherein:

said central body has an axial length; and,

at least one of said radial members is a continuous fin extending over the full extent of said axial length.

11. The flow enhancer of claim 9, wherein:

said central body has an axial length; and,

said radial members comprise a plurality of fins that extend along a portion of said axial length.