US20040099403A1

US20040099403A1 - Heat exchanger system having nonmetallic finless tubes

Info

Publication number: US20040099403A1
Application number: US10/305,425
Authority: US
Inventors: Ronald Dupree
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2002-11-26
Filing date: 2002-11-26
Publication date: 2004-05-27

Abstract

A heat exchanger system includes one or more nonmetallic finless heat exchanging tubes. The heat exchanging tubes are coiled around a central axis, and vehicle fluid flowing through the tubes is cooled or heated by airflow perpendicular to the central axis.

Description

TECHNICAL FIELD

The present invention relates to a heat exchanger system and, more particularly, to such a system for a vehicle wherein the heat exchanger includes a radial fan and at least one nonmetallic finless heat exchanging tube.

BACKGROUND

It is well-known that many different applications require heat exchanger systems to change the temperature of a fluid. In vehicle applications, a radiator having a fan and multiple rows of heat exchanging tubes is commonly used to disperse heat from a circulating engine coolant in order to prevent the engine from overheating and becoming damaged. Additionally, other vehicle fluid systems, such as hydraulics, engine lubrication, and operator compartment heating/ventilating/air conditioning (“HVAC”) systems, may require a working fluid to be heated or cooled during operation of the machine.

A traditional radiator is generally an arrangement of one or more lengthy heat exchanging tubes coiled or bent to form a desired shape. Should the heat exchanging tubes be provided with fins for better heat dispersal, care in manufacturing and operation is needed to avoid damage to the fins. These finned tubes are also more difficult and expensive to make than a finless tube. Finally, a metallic heat exchanging tube is highly subject to corrosion and heat-related metal fatigue in the course of carrying the often caustic and hot fluids needed to operate a vehicle.

U.S. Pat. No. 914,822, issued Mar. 9, 1909 to Maurice Goudard et al. (hereafter referenced as '822) discloses a cooling device with force (sic) air circulation for the motors of motor cars. The '822 device includes a radiating bundle (of tubes) at the center of which is mounted a centrifugal fan. Air for the fan is supplied through a chamber and forced through the radiating bundle and out through the periphery of the apparatus. Since no detail is given regarding the design of the tubes, presumably they are of the finned metallic type commonly used at that time. '822 fails to teach a cost-effective manufacture of the heat exchanger system or composition of the tubes.

The present invention is directed to overcoming one or more of the problems as set forth above.

SUMMARY OF THE INVENTION

In an exemplary embodiment of the present invention, a heat exchanger system is disclosed. The heat exchanger system includes one or more nonmetallic finless heat exchanging tubes, each heat exchanging tube being coiled one or more times around a central axis to allow airflow perpendicular to the central axis. A vehicle fluid circulates through each heat exchanging tube.

In an exemplary embodiment of the present invention, a vehicle is disclosed. The vehicle includes a vehicle chassis, a load compartment carried by the vehicle chassis, an engine located within an engine compartment and adapted to provide power to the vehicle, and a heat exchanger system. The heat exchanger system is located within the engine compartment adjacent the engine, and includes one or more nonmetallic finless heat exchanging tubes, each heat exchanging tube being coiled one or more times around a central axis to allow airflow perpendicular to the central axis. A vehicle fluid circulates through each heat exchanging tube.

In an exemplary embodiment of the present invention, a method of manufacturing a heat exchanging system is disclosed. The method includes the steps of: coiling one or more flexible, nonmetallic, finless heat exchanging tubes one or more times about a central axis, arranging the heat exchanging tubes to allow airflow therebetween in a direction perpendicular to the central axis, and providing an interface to each heat exchanging tube such that a vehicle fluid can be circulated therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an exemplary embodiment of the present invention; [0009]
FIG. 2 is a cross sectional side view taken along line [0010] 2-2 of FIG. 1; and
FIG. 3 is a schematic of a vehicle including an exemplary embodiment of the present invention.[0011]

DETAILED DESCRIPTION

FIG. 1 depicts a [0012] heat exchanger system 100 for use in any suitable application, but described herein as used in a vehicle. The heat exchanger system 100 includes an airflow source 102 which rotates about a central axis 104. The airflow source 102, described herein as a fan 102, is operative to force air radially perpendicular to the central axis 104. The fan 102 may blow air away from the central axis 104 or suck air toward the central axis 104. An exemplary embodiment includes a radial or centrifugal fan 102, preferably of the backward curved type for efficiency.
The airflow produced by the [0013] fan 102 passes over one or more nonmetallic finless heat exchanging tubes 106 coiled around the central axis 104, illustrated in FIG. 1. By finless, it is meant that the heat exchanging tubes 106 are devoid of any protrusions intended primarily to increase heat dispersal. Such finless heat exchanging tubes 106 may be easily produced using, for example, an extrusion molding process. By coiled, it is meant that a single heat exchanging tube 106 is arranged in one or more turns about the central axis 104. Portions of each coiled heat exchanging tube 106 may be spaced apart along the central axis 104 and/or may be differing distances radially spaced from the central axis 104. The nonmetallic nature of the heat exchanging tubes 106 renders them more resistant to corrosion than traditional metal tubes. The heat exchanging tubes 106 may be made of a plastic or any other suitable material. A flexible material—i.e., a material able to be readily bent or shaped into a desired configuration—may be desirable during manufacture of an exemplary embodiment of the present invention, as described below.
Experimentation has shown that [0014] heat exchanging tubes 106 having relatively small outer diameters—e.g., between 1 and 10 millimeters—are appropriate in many applications, but no limitation on the size of the heat exchanging tubes 106 is to be implied. In practice, it is contemplated that a heat exchanging tube 106 having a large surface area to volume ratio will be chosen to cool or heat the fluid as needed for the specific application. The heat exchanging tubes 106 may be of circular cross section, as shown in FIG. 2, or of any other cross-sectional shape chosen for an individual heat exchanger system 100 application.
FIG. 2 depicts a sectional view of the [0015] heat exchanger system 100, taken along lines 2-2 of FIG. 1. The small circles in FIG. 1 represent sections through one or more coiled heat exchanging tubes 106 or portions thereof. While a single heat exchanging tube 106 could be coiled around the central axis 104 several times to produce the same effect, the sections in FIG. 2 will be described as separate heat exchanging tubes 106 for clarity, rather than as portions of one or more heat exchanging tubes 106.
The [0016] heat exchanging tubes 106 are located at varying distances radially spaced from the central axis 104. FIG. 2 illustrates an exemplary embodiment wherein substantially concentric tube circles a, b, and c are located at predetermined distances from the central axis 104. In the case of a single heat exchanging tube 106 coiled around the fan 102 multiple times, it is intuitively obvious that the predetermined distances of a, b, and c may vary slightly at differing points along the circumference of the fan 102 and provide a spiraling aspect to the distance of the heat exchanging tube 106 from the central axis 104 at varying radii of the coiled heat exchanging tube 106. The tube circles a, b, and c need not be used to define required heat exchanging tube 106 positions, should a more random “bundle” arrangement of heat exchanging tubes 106 be desired. The heat exchanging tubes 106 may also or instead be coiled such that portions of each heat exchanging tube 106 are located at differing predetermined locations along the central axis 104 (“along” being in a horizontal direction in the FIG. 2 orientation), regardless of the radial position of the heat exchanging tube 106 with respect to the central axis 104, to allow for greater efficiency in operation of the heat exchanger system 100.
FIG. 2 includes [0017] optional spacers 202 adapted to hold the heat exchanging tubes 106 apart from each other to facilitate airflow in a radial direction between the heat exchanging tubes 106. The spacers 202, when included, may be formed integrally with the heat exchanging tubes 106, such as raised bumps or rings which contact other heat exchanging tubes 106 when coiled to maintain airflow space between the heat exchanging tubes 106. In addition, the spacers 202, whether integral with or separate from the heat exchanging tubes 106, may be made of any suitable material, and may serve to conduct heat between the airflow and the heat exchanging tubes 106. Finally, the spacers 202 may be placed in any random or ordered position, along any length of the heat exchanging tubes 106, to produce a desired airflow response between the heat exchanging tubes 106.
A [0018] core element 204 is preferably used to provide a fluid path between an interface (not shown, could be as simple as an open end) to at least one heat exchanging tube 106 and a vehicle fluid system, in a known manner. The core element 204 may interface one or more times with each individual heat exchanging tube 106 as desired, independent of the number of times each heat exchanging tube 106 is coiled about the central axis 104.

INDUSTRIAL APPLICABILITY

As depicted in schematic form in FIG. 3, a [0019] vehicle 300 includes a vehicle chassis 302, a load compartment 304, and an engine 306. The load compartment 304 is carried on the vehicle chassis 302 and may be adapted to carry cargo and/or one or more passengers. The engine 306 is located inside an engine compartment 308 carried on the vehicle chassis 302. Also located in the engine compartment 308 adjacent the engine 306 is the heat exchanger system 100 of the present invention. Preferably, the heat exchanger system 100 is not separated from the engine 306 by any intermediate walls, in order to better circulate air within the engine compartment 308.
The [0020] vehicle 300 includes one or more vehicle fluid systems 310. Examples of suitable vehicle fluid systems 310 are engine 306 cooling, HVAC for the load compartment 304, engine 306 lubrication, hydraulics, and the like. The fluids (liquid, plasma, or vapor) used in the vehicle fluid systems 310 will be collectively referenced as vehicle fluids. The vehicle fluid examples given herein are cooled by the heat exchanger system 100, but a vehicle fluid system 310 in which the heat exchanger system 100 warms the vehicle fluid is also contemplated by the present invention.
Each [0021] heat exchanging tube 106 is associated with a single vehicle fluid system 310 at any given time. However, multiple vehicle fluid systems 310 could use the same heat exchanging tube 106 at different times if cross-contamination of vehicle fluids is not a concern. A vehicle fluid circulates through each heat exchanging tube 106. A core element 204 passes vehicle fluid between the originating vehicle fluid system 310 and at least one associated heat exchanging tube 106 in a known manner. Heat exchanging tubes 106 carrying different vehicle fluids may be coiled as desired around the fan 102. The fan 102 forces air past the heat exchanging tubes 106 and convection from the airflow carries heat away from the vehicle fluid. The vehicle fluid is then passed through the core element 204 and back into circulation through the vehicle fluid system 310.
Manufacture of an exemplary embodiment of the [0022] heat exchanger system 100 is relatively simple. One or more heat exchanging tubes 106 are merely each coiled, singly or concurrently, to form the desired arrangement, an example of which is shown in FIGS. 1 and 2. Each heat exchanging tube 106 may be associated with one or more spacers 202 as desired at any suitable time before, during, or after the coiling. Optionally, a frame or template is provided about or within which flexible heat exchanging tubes 106 may be wrapped to quickly and easily form the desired arrangement. If provided, the frame or template may be removed once the heat exchanging tubes 106 are coiled or may remain with the heat exchanging tubes 106 for ease of transport, storage, and/or assembly. A manufacturer can quickly and easily produce arrangements of heat exchanging tubes 106 of any desired size or shape—without expensive retooling of the assembly line—by simply varying the size and/or configuration of at least one of the heat exchanger tubes 106 and the frame or template (should such be provided).
Other aspects, objects and advantages of the present invention can be obtained from a study of the drawings, the disclosure and the appended claims. [0023]

Claims

What is claimed is:

1. A heat exchanger system, comprising:

one or more nonmetallic finless heat exchanging tubes, each heat exchanging tube being coiled one or more times around a central axis to allow airflow perpendicular to the central axis, and wherein a vehicle fluid circulates through each heat exchanging tube.

2. The heat exchanger system of claim 1, including a fan adapted to provide airflow perpendicular to the central axis.

3. The heat exchanger system of claim 1, wherein the heat exchanging tubes are of circular cross-section.

4. The heat exchanger system of claim 1, wherein multiple heat exchanging tubes or portions thereof are located at differing predetermined locations along the central axis.

5. The heat exchanger system of claim 1, wherein multiple heat exchanging tubes or portions thereof are located at differing predetermined radii from the central axis.

6. The heat exchanger system of claim 1, wherein the vehicle fluid is at least one of: an engine cooling fluid, an air conditioning fluid, a heating fluid, an engine lubrication fluid, and a hydraulic fluid.

7. The heat exchanger system of claim 1, including spacers separating portions of at least one heat exchanging tube from other portions of the heat exchanging tube or from portions of another heat exchanging tube.

8. The heat exchanger system of claim 1, including at least one core element associated with at least one heat exchanging tube and providing a fluid path interface between the heat exchanging tube and a vehicle fluid system.

9. The heat exchanger system of claim 1, wherein the heat exchanger tubes are formed of a flexible material.

10. A vehicle, comprising:

a vehicle chassis;

a load compartment carried by the vehicle chassis;

an engine, located within an engine compartment and adapted to provide power to the vehicle; and

a heat exchanger system, located within the engine compartment adjacent the engine, wherein the heat exchanger system includes:

11. The vehicle of claim 10, including a fan adapted to provide airflow perpendicular to the central axis.

12. The vehicle of claim 1, wherein the heat exchanging tubes are of circular cross-section.

13. The vehicle of claim 10, wherein multiple heat exchanging tubes or portions thereof are located at differing predetermined locations along the central axis.

14. The vehicle of claim 10, wherein multiple heat exchanging tubes or portions thereof are located at differing predetermined radii from the central axis.

15. The vehicle of claim 10, wherein the vehicle fluid is at least one of: an engine cooling fluid, an air conditioning fluid, a heating fluid, an engine lubrication fluid, and a hydraulic fluid.

16. The vehicle of claim 10, including spacers separating portions of at least one heat exchanging tube from other portions of the heat exchanging tube or from portions of another heat exchanging tube.

17. The vehicle of claim 10, including at least one core element associated with at least one heat exchanging tube and providing a fluid path interface between the heat exchanging tube and a vehicle fluid system.

18. The vehicle of claim 10, wherein the heat exchanger tubes are formed of a flexible material.

19. A method of manufacturing a heat exchanging system, comprising:

coiling one or more flexible, nonmetallic, finless heat exchanging tubes one or more times about a central axis;

arranging the heat exchanging tubes to allow airflow therebetween in a direction perpendicular to the central axis; and

providing an interface to each heat exchanging tube such that a vehicle fluid can be circulated therethrough.

20. The method of claim 19, including:

providing spacers to allow airflow between the heat exchanging tubes in a direction perpendicular to the central axis.