Heat exchange – Side-by-side tubular structures or tube sections – With manifold type header or header plate
Reexamination Certificate
2003-02-25
2004-05-25
McKinnon, Terrell (Department: 3743)
Heat exchange
Side-by-side tubular structures or tube sections
With manifold type header or header plate
C165S177000, C165S153000, C138S038000
Reexamination Certificate
active
06739387
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to heat exchanger tubing for heat exchanger construction, and particularly to multivoid tubing that can be used in a heat exchanger without the need for fin stock.
BACKGROUND ART
In the prior art, heat exchanger design typically includes a series of fins and tubes. The tubes act as conduits for fluid flow whereby heat from an operating device such as an air conditioner is brought to the heat exchanger. The fins are attached to the tubes and allow the transfer of heat from the tubes to the surrounding media, typically air.
While heat exchangers are used in a vast array of applications, one popular use is in the automotive field, wherein condensers as heat exchangers are used in conjunction with automotive air conditioning. These types of heat exchangers are made using essentially two different designs. A first design uses round tubing and bare fins that are mechanically attached to the round tubes by first lacing the tubes into holes punched in the fins, and then expanding the tubes to ensure that the tube's outer surface is in close contact with the fins.
A second design uses a flat tubing having a plurality of channels in the tubing, commonly referred to as multivoid tubing. Referring to
FIG. 1
, an exemplary tubing is designated by the reference numeral
10
, and includes a number of parallel flow channels
3
that are separated by a web(s) or wall(s)
5
that are aligned along the longitude of the tubing or generally perpendicular to the opposing surfaces
7
and
9
. The cross section of the flow channels can vary, e.g., circular, oval, square, rectangular, of other regular or irregular shapes. The inner walls of the channels can be smooth or rough. In making these types of heat exchangers, the tubes are joined to corrugated fins using a brazing process. Typically, these types of multivoid tubing are about 10-25 mm in width, about 1-2 mm in height, and around 500-750 mm in length.
FIG. 2
shows a partial schematic perspective view of a typical installation of the tubing
10
in a heat exchanger assembly
20
. The tubing
10
is attached at one end to a header
21
(attachment to an opposing header is not shown), and separated from an adjacent tubing
10
by fin stock
23
. A series of tubes separated by fin stock form the entire heat exchanger. Fluid flows from the header
21
and through the channels
3
in the tubing
10
to the other header. The fin stock
23
assists in heat exchange via its close or brazed contact with the tubing, and high surface area. The tubing
10
, fin stock
23
and headers
21
form a plane that is generally perpendicular to the direction of air or other fluid flowing past the assembly
20
as represented by arrow “A”.
Another proposed design is disclosed in WO 02/16834 to Moser et al. In one aspect of the designs disclosed in this publication, a finless construction is shown wherein multivoid tubes are formed into a serpentine shape. While this shape increases the surface area of the tube to enhance heat transfer, it also intensifies air turbulence passing over the tubing. This creates an unwanted pressure drop across the tubing, and compromises the enhanced heat transfer created by the tubing configuration.
In light of the disadvantages associated with prior art tubing and heat exchanger assembly design, a need exists for improved tubing design, as well as improved heat exchanger assembly design. The present invention is a response to this need by providing an improved tubing design that overcomes the deficiencies of prior art designs, and allows for the assembly of a heat exchanger at reduced costs and manufacturing times.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide an improved heat exchanger tubing design.
Another object of the invention is a heat exchanger that uses a series of the inventive tubing without fin stock.
A still further object of the invention is heat exchanger tubing that offers a simpler heat exchanger construction while maintaining a high degree of heat exchange.
Other objects and advantages of the invention will become apparent as the description thereof proceeds.
In satisfaction of the foregoing objects and advantages, the present invention is an improvement in heat exchanger tubing that employs a number of channels for fluid flow, wherein adjacent channels are separated by an inner wall that extends between top and bottom surfaces of the tubing. According to the invention, the inner wall separating the channels of the tubing is angled with respect to the top and bottom surfaces of the tubing. In addition, a number of passageways or through openings are provided in the tubing, each opening extending between opposing surfaces and within a given inner wall of the tubing.
By using this design, the tubing can be used in a heat exchanger assembly but does not require the presence of fin stock in contact with the tubing; the tubing can be arranged in a spaced apart parallel fashion between headers. When used in a heat exchanger assembly, the tubing is tilted with respect to the direction of air flow passing through the assembly so that the openings in the inner channel walls are aligned with the air flow direction. This enhances the heat exchange characteristic of the assembly and allows the air to pass through the assembly with less of a pressure drop.
The openings in the inner channel walls can be arranged along the longitude or transverse dimension in any number of ways, e.g., each opening aligned transversely and spaced apart along the length of the tube in set distances. Alternatively, only some openings can be aligned in the transverse direction, and the longitudinal spacing of the openings could vary among channel walls.
The tubing can be any type of multivoid tubing, but is preferably an extruded tubing made from non-ferrous metal alloys that are typically used in heat exchange applications.
The angle of the inner wall as measured from one of the opposing surfaces can range from 2 to 88 degrees with more preferred ranges including 10-60 degrees, and 20-40 degrees.
The openings in the inner channel walls can have regular or irregular cross sectional shapes. The surfaces of the openings in the inner channel can be smooth or include fins or other surface area-increasing enhancements. The tubing itself can be formed into the conventional flat tubing shape, or have an irregular shape for use in special applications. The tubing can also be formed such that the top and bottom walls form surfaces that have a shape that is not flat, e.g., undulating, stepped or the like. The tubing channels can be made with a variety of cross section shapes and surfaces as is used in conventional multivoid tubing.
REFERENCES:
patent: 1622664 (1927-03-01), Murray et al.
patent: 2151540 (1939-03-01), Varga
patent: 2911199 (1959-11-01), Huet
patent: 4766953 (1988-08-01), Grieb et al.
patent: 5553377 (1996-09-01), Hirano et al.
patent: 6357522 (2002-03-01), Dienhart et al.
patent: 6622785 (2003-09-01), Haegele et al.
patent: 1-312390 (1989-12-01), None
patent: 1-312391 (1989-12-01), None
patent: WO 02/16834 (2002-02-01), None
Alcoa Inc.
McKinnon Terrell
Pearce-Smith David W.
LandOfFree
Heat exchanger tubing and heat exchanger assembly using said... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Heat exchanger tubing and heat exchanger assembly using said..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Heat exchanger tubing and heat exchanger assembly using said... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3190281