U.S. patent number 3,831,672 [Application Number 05/259,095] was granted by the patent office on 1974-08-27 for liquid-to-liquid heat exchanger.
This patent grant is currently assigned to Ford Motor Company. Invention is credited to Sylvester J. Battisti.
United States Patent |
3,831,672 |
Battisti |
August 27, 1974 |
LIQUID-TO-LIQUID HEAT EXCHANGER
Abstract
A liquid-to-liquid heat exchanger adapted especially for use
with an automotive vehicle radiator assembly for transferring heat
from automatic power transmission fluid to the engine liquid
coolant comprising a pair of cylindrical tubes adapted to be
positioned in coaxial disposition within the engine radiator heater
and a helical turbulator positioned within an annular space defined
by the cylindrical tubes, said turbulator comprising a rolled strip
with a channel cross-section, said strip being wound about the axis
of the heat exchanger to form a continuous helical flow channel,
thus increasing the turbulence in the field flow path for the
transmission oil.
Inventors: |
Battisti; Sylvester J.
(Westland, MI) |
Assignee: |
Ford Motor Company (Dearborn,
MI)
|
Family
ID: |
26829337 |
Appl.
No.: |
05/259,095 |
Filed: |
June 2, 1972 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
131306 |
Apr 5, 1971 |
|
|
|
|
Current U.S.
Class: |
165/154; 165/156;
165/184 |
Current CPC
Class: |
F28F
9/0234 (20130101); F28F 13/12 (20130101) |
Current International
Class: |
F28F
13/12 (20060101); F28F 9/02 (20060101); F28F
13/00 (20060101); F28d 007/10 () |
Field of
Search: |
;165/154,155,183-186,141,181,153,184 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myhre; Charles J.
Assistant Examiner: Streule, Jr.; Theophil W.
Attorney, Agent or Firm: Harrington; Donald J. Zerschling;
Keith L.
Parent Case Text
REFERENCE TO RELATED DISCLOSURE
This is a continuation-in-part of application Ser. No. 131,306,
filed Apr. 5, 1971, now abandoned.
Claims
Having thus described a perferred form of my invention, what I
claim and desire to secure by U.S. Letters Patent is:
1. A liquid-to-liquid heat exchanger adapted especially for use
with an automatic power transmission mechanism for cooling oil
circulated through the transmission mechanism and adapted to be
mounted in liquid coolant within an air cooled radiator for a
liquid-cooled automotive engine comprising a pair of heat exchanger
shells of generally tubular construction, one shell being situated
within the other in coaxial disposition, said coolant circulating
over the outer surface of the outermost shell and over the inner
surface of the innermost shell, said shells defining therebetween
an annular space, a turbulator construction situated in said
annular space, a fluid fitting connected to the outermost shell for
receiving transmission oil and a fluid flow outlet fitting
connected to said outermost shell for receiving transmission oil
circulated through said cooler, the flow paths defined in part by
said fittings communicating with said annular space at axially
spaced locations, said turbulator construction registering with
said shells and forming therebetween a helical flow path for the
fluid flow that passes from one of said fittings to the other, said
turbulator construction comprising two parts, the first part being
a helical wire surrounding the innermost skill and engaging the
adjacent shell surfaces to prevent crossflow from one point in the
helical flow path to another in an axial direction, the geometric
axis of the helical flow path formed by said turbulator
construction the second turbulator construction being a turbulator
ribbon having a plurality of undulations located between the
helical wire and forming in said ribbon liquid flow openings, said
ribbon being wrapped around the innermost shell in helical
disposition whereby the flow path is generally helical and is
characterized by localized turbulance.
Description
GENERAL DESCRIPTION OF THE INVENTION
The heat exchanger construction of my invention is adapted to be
used for cooling oil used with an automatic transmission in an
automotive vehicle driveline. Such transmissions usually include a
hydrokinetic torque converter which multiplies engine torque before
it is distributed to transmission gearing. The inherent slip in the
torque converter causes a horsepower loss which results in heating
of the transmission oil. It is necessary in arrangements of this
type to circulate the oil continuously through the converter and
through an oil cooler in order to maintain a stabilized temperature
during operation of the driveline under power.
The transmission oil cooler usually is situated in the lower
radiator tank for the liquid-to-air heat exchanger or radiator used
for the cooling of the engine coolant for the internal combustion
engine. The coolant is circulated through a cooling jacket within
the engine block of the internal combustion engine. It is
circulated also through the vehicle radiator located in the moving
ambient air stream.
I am aware of several transmission oil cooler constructions in
arrangements of this type, including the construction shown in U.S.
Pat. Nos. 3,116,541 and 3,265,127. Each of these prior art
constructions includes a so-called turbulator located between an
inner and outer heat exchanger shell of generally tubular
construction. The turbulator causes turbulence in the fluid flow
path for the transmission oil that is circulated through the
transmission cooler in order to assist in heat transfer from one
liquid medium to the other.
It is a principal feature of my invention to improve upon the heat
transfer characteristics of heat exchangers of the type presently
used in the automotive industry by increasing the effective length
of the fluid flow path as the fluid passes through the oil cooler.
This length of the path increases the time during which the heated
transmission oil is exposed to the cooled surfaces of the heat
exchanger construction that are in contact with the liquid coolant
in the engine radiator. It is possible to reduce the effective size
and to change the shape and dimensions of the transmission oil
cooler to meet design and space limitations without adversely
affecting the ability of the heat exchanger to maintain a
stabilized temperature for the transmission oil at the desired
operating temperature level. The improved performance of my heat
exchanger is achieved by using a simplified construction that lends
itself to simplified manufacturing techniques. My improved heat
exchanger construction includes inner and outer shells and a
centrally disposed turbulator that is comprised of a continuous
rolled ribbon. A channel is rolled by means of a suitable rolling
die which forms the ribbon along its length. The dies may be
designed so that curling of the rolled ribbon stock takes place as
the channel cross-section is formed. The rolled ribbon may be
coiled into a cylinder and assembled between the inner and outer
cooler shells, the ends of which may be sealed by welding. Suitable
fluid fittings then may be secured to the outermost shell to
accommodate transfer of transmission oil through the helical fluid
flow path defined by the turbulator and the cooperating cooler
shells.
The length of the fluid flow path through the turbulator can be
varied simply by varying the width of the ribbon.
BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING
FIG. 1 shows a side elevation view partly in cross-section of my
improved heat exchanger assembly;
FIG. 2 is a cross-sectional view taken along the plane of section
line 22 of FIG. 1;
FIG. 3 is a side elevation view of the turbulator element used in
the assembly of FIG. 1;
FIG. 4 is a cross-sectional view of the turbulator shown in FIG.
3;
FIG. 5 is a partial view of an unwrapped section of the ribbon
stock used and formed in a turbulator of FIGS. 3 and 4.
FIG. 6 is a detail view showing a modified turbulator as it would
appear in a wrapped condition following assembly.
FIG. 7 is a cross-sectional view taken along the plane of line 7--7
of FIG. 6.
FIG. 8 shows a side elevation view partly in cross-section showing
the modified turbulator of FIGS. 6 and 7 therein.
PARTICULAR DESCRIPTION OF THE INVENTION
Numeral 10 in FIGS. 1 and 2 designates a cylindrical outer shell
for the heat exchanger of my invention. It surrounds the
cylindrical shell 12. The ends of shell 12 are formed with an
enlarged diameter section, as indicated at 16 and 18. The sections
16 and 18 engage the inner surface of the shell 10 and it may be
secured to the shell 10 by welding.
The shells 10 and 12 form an annular space 20 extending from one
end of the assembly to the other. A fluid inlet fitting 22
surrounds an inlet opening 24 formed in the shell 10.
Fitting 22 is threaded at 26 to permit a connection with a fluid
transmission line extending to the automatic transmission.
A fitting 28, which is similar to the fitting 22, is formed in the
shell 10 at the opposite end of the assembly shown in FIG. 1. It
serves as an outlet flow passage for the transmission oil
circulated through the assembly.
Positioned within the annular space defined by the shells 10 and 12
is the turbulator shown in FIGS. 3 and 4. This comprises a coiled,
rolled ribbon of the type shown in FIG. 5. The ribbon is rolled to
form a channel, the rolling dies having peripheries formed with the
cross-sectional shape indicated in FIG. 4. After the rolling
operation is completed, it is coiled in end-to-end relationship, as
indicated in FIG. 4, so that its inside diameter is slightly larger
than the outside diameter of the shell 12. The height of the
channel, which is indicated by reference character 30, is slightly
less than the radial thickness of the annular space between the
shells 10 and 12.
Fluid entering the fluid fitting 22 is received within the fluid
channels of the turbulator. The fluid circulates in a helical path
through the turbulator and then is received at the fitting 28 and
returned through a suitable fluid conduit to the transmission. The
assembly shown in FIG. 1 is placed in the lower header of the
automotive radiator so that the engine coolant circulates around
the outer surface of the shell 10 and over the inner surface of the
shell 12.
The helical flow path produced by the turbulator increases the time
of exposure of the heated oil to the coolant in the radiator
header, thereby improving the heat transfer capability of the
cooler.
The helical flow path for the heated oil can be defined also by a
turbulator of the type shown in FIG. 6. This includes a helical
wire 32 which would be wrapped about the shell 12 within the
annular space defined by the shell 12 and the shell 10. It engages
both shells and defines a helical flow path. The wire 32 forms a
seal which prevents cross flow. Situated between the spaced
windings of the wire 32 is a ribbon or strip 34. The strip 34 is
formed with indentations which comprise a series of alternately
spaced undulations shown at 36 and at 38. The undulations 36 are
out of phase with respect to the undulations 38 so that apertures
are formed between them. These apertures permit turbulant fluid
flow through the heat exchanger as the fluid flow traverses the
helical circuit.
* * * * *