U.S. patent application number 10/256594 was filed with the patent office on 2003-02-06 for accumulator with internal heat exchanger.
This patent application is currently assigned to Visteon Global Technologies, Inc.. Invention is credited to Zhang, Chao A..
Application Number | 20030024267 10/256594 |
Document ID | / |
Family ID | 25026246 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030024267 |
Kind Code |
A1 |
Zhang, Chao A. |
February 6, 2003 |
Accumulator with internal heat exchanger
Abstract
An accumulator with an internal heat exchanger for use in an air
conditioning or refrigeration system having a compressor, a
condenser, an expansion device, and an evaporator is disclosed. In
operation, the accumulator is placed in the system so high
pressure, high temperature refrigerant flowing from the condenser
and low pressure, low temperature refrigerant flowing from the
evaporator simultaneously enter and flow through the heat exchanger
disposed in the accumulator whereby the low pressure, low
temperature refrigerant absorbs heat and thereby cools the high
pressure, high temperature refrigerant. In one embodiment, the heat
exchanger comprises a tube having at least one high temperature
channel and one low temperature channel extending through the
interior of the tube. In a second embodiment, the heat exchanger
comprises a single spirally wound coaxial tube having an outer tube
and an inner tube positioned within the outer tube. In a third
embodiment, the heat exchanger comprises a plurality of coaxial
tubes, each coaxial tube having an outer tube and an inner tube
positioned in the outer tube wherein the inner tubes are fluidly
connected.
Inventors: |
Zhang, Chao A.; (Canton,
MI) |
Correspondence
Address: |
Carmen Matos Michaesl
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Visteon Global Technologies,
Inc.
|
Family ID: |
25026246 |
Appl. No.: |
10/256594 |
Filed: |
September 27, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10256594 |
Sep 27, 2002 |
|
|
|
09752419 |
Dec 29, 2000 |
|
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|
Current U.S.
Class: |
62/503 ;
62/513 |
Current CPC
Class: |
F25B 43/006 20130101;
F25B 2309/06 20130101; F25B 2400/051 20130101; F28F 2260/02
20130101; F25B 9/008 20130101; F25B 40/00 20130101; F28D 7/0033
20130101; F28D 7/04 20130101; F28D 7/14 20130101 |
Class at
Publication: |
62/503 ;
62/513 |
International
Class: |
F25B 043/00; F25B
041/00 |
Claims
1. An accumulator for an air conditioning or refrigeration system
comprising: a housing, said housing comprising an upper portion and
a lower portion joined together to form a chamber; a high pressure
inlet port for conveying a high pressure refrigerant from a
condenser into the accumulator; a high pressure outlet port for
discharging the high pressure refrigerant from the accumulator to
an evaporator; a low pressure inlet port for conveying low pressure
refrigerant from an evaporator into the accumulator; a low pressure
outlet port for discharging the low pressure refrigerant from the
accumulator to a compressor; and a vapor conduit tube for conveying
the low pressure refrigerant in the accumulator to a heat exchanger
disposed in the chamber, said heat exchanger comprising at least
one tube having an interior, a internal end, an external end, at
least one low temperature channel, and at least one high
temperature channel, each channel extending through the interior of
the tube, wherein the external end of the high temperature channel
is connected to the high pressure inlet port, the external end of
the low temperature channel is connected to the low pressure outlet
port, the internal end of the low temperature channel is connected
to the vapor conduit tube, and the internal end of the high
temperature channel is connected to the high pressure outlet
port.
2. The accumulator of claim 1 wherein the housing is
cylindrical.
3. The accumulator of claim 1 wherein the heat exchanger is
spirally wound and the internal end is located interiorly in the
spiral.
4. The accumulator of claim 1 further comprising a deflector
positioned within said housing.
5. The accumulator of claim 4 wherein the deflector is dome
shaped.
6. The heat exchanger of claim 1 wherein said high temperature and
said low temperature channels comprise adjacent rows of
microchannels.
7. The heat exchanger of claim 1 wherein the refrigerant flows
through the low temperature channel in a direction opposite the
flow of refrigerant through the high temperature channel.
8. An accumulator for an air conditioning or refrigeration system
comprising: a hollow housing having a top and a bottom joined
together to form a closed chamber; and a heat exchanger disposed in
the housing, said heat exchanger comprising at least one tube
defining at least one high temperature channel therethrough, and at
least one low temperature channel therethrough, wherein a
refrigerant discharged from a condenser enters the accumulator and
flows through the high temperature channel before being discharged
to an evaporator, and a refrigerant discharged from the evaporator
enters the accumulator and flows through the low temperature
channel in a heat exchange relationship with refrigerant flowing
through the high temperature channel before being discharged to a
compressor.
9. The accumulator of claim 8 wherein the refrigerant flowing
through the high temperature channel flows in the opposite
direction of the refrigerant flowing through the low temperature
channel.
10. The accumulator of claim 8 further comprising a deflector
positioned in said housing.
11. The heat exchanger of claim 8 wherein the said high temperature
and said low temperature channels comprise adjacent rows of
microchannels.
12. A method of operating an air conditioning or refrigeration
cycle comprising: conveying condensed refrigerant into an
accumulator having an internal heat exchanger, said heat exchanger
comprising at least one tube defining at least one high temperature
channel therethrough and at least one low temperature channel
therethrough, conveying the condensed refrigerant through the high
temperature channel of the heat exchanger; discharging refrigerant
from the high temperature channel and accumulator; evaporating the
refrigerant; conveying the evaporated refrigerant through a vapor
conduit tube positioned in the accumulator and into the low
temperature channel to flow in a heat exchange relationship with
refrigerant flowing through the high temperature channel;
discharging the evaporated refrigerant from the low temperature
channel and accumulator; and conveying the discharged evaporated
refrigerant to a compressor.
13. The method of claim 12 wherein the low temperature and high
temperature channels comprise a plurality of microchannels.
14. An accumulator for an air conditioning or refrigeration system
comprising: a hollow housing having a top and a bottom; a low
pressure inlet port extending through a first opening defined in
the top for conveying a refrigerant from an evaporator into the
housing; a low pressure outlet port extending through a second
opening defined in the top for discharging refrigerant from a heat
exchanger positioned in the housing to a compressor; a high
pressure inlet port extending through a third opening defined in
the top for conveying refrigerant from a condenser to the heat
exchanger; a high pressure outlet port extending through a fourth
opening in the top for discharging refrigerant from the heat
exchanger to an evaporator; and a vapor conduit tube having first
and second ends for conveying refrigerant in the accumulator
housing to the heat exchanger, said heat exchanger comprising an
outer tube having a first outer tube end and a second outer tube
end, and an inner tube positioned within the outer tube having a
first inner tube end and a second inner tube end, wherein the high
pressure inlet port is attached at the first inner tube end, the
high pressure outlet tube is attached at the second inner tube end,
the first vapor conduit end is attached at the first outer tube end
and the low pressure outlet port is attached at the second outer
tube end.
15. The accumulator of claim 14 wherein the heat exchanger is
spirally shaped.
16. The accumulator of claim 14 further comprising a deflector
positioned within said housing.
17. An accumulator for an air conditioning or refrigeration system
comprising: a hollow housing having a top and a bottom; a heat
exchanger disposed in the housing, said heat exchanger comprising a
helical coaxial tube having an outer tube and an inner tube
disposed within the outer tube, wherein a refrigerant from a
condenser flows into the accumulator and through the inner tube and
simultaneously a refrigerant from an evaporator flows into the
accumulator and through the outer tube in a heat exchange
relationship.
18. A method of operating an air conditioning or refrigeration
system comprising: conveying condensed refrigerant through a high
pressure inlet port into an accumulator having an internal heat
exchanger, said heat exchanger comprising an outer tube having a
first outer tube end and a second outer tube end, and an inner tube
positioned within the outer tube having a first inner tube end and
a second inner tube end wherein the high pressure inlet port is
attached at the first inner tube end, a high pressure outlet tube
is attached at the second inner tube end, a vapor conduit tube is
attached at the first outer tube end, and a low pressure outlet
port is attached at the second outer tube end; conveying the
condensed refrigerant through the inner tube of the heat exchanger;
discharging the condensed refrigerant from the inner tube of the
heat exchanger and accumulator through the high pressure outlet
port; evaporating the refrigerant; conveying the evaporated
refrigerant into the accumulator through the low pressure inlet
port; conveying the evaporated refrigerant through the vapor
conduit tube and into the outer tube in a heat exchange
relationship with the refrigerant flowing through the inner tube;
discharging the evaporated refrigerant from outer tube and
accumulator through the low pressure outlet port; and conveying the
evaporated refrigerant to a compressor.
19. The method of claim 18 wherein the heat exchanger is helically
shaped.
20. The method of claim 18 wherein the accumulator further
comprises a deflector positioned within said accumulator.
21. An accumulator for an air conditioning or refrigeration system
comprising: a top, an upper shell, a plate, a lower shell, and a
bottom, wherein said top, upper shell, plate, lower shell and
bottom form a closed housing having an upper chamber and a lower
chamber separated by the plate; a low pressure inlet port extending
into the upper chamber; a vapor conduit tube extending through the
top, into the upper chamber, through an opening in the plate, and
into the lower chamber; a heat exchanger comprising a plurality of
coaxial tubes at least partially within said housing, each coaxial
tube further comprising an outer tube and an inner tube disposed
within the outer tube, said inner tube extending through the top,
into the upper chamber, through the plate, into the lower chamber
and through the bottom, said outer tube extending through the upper
chamber, through the plate, and into the lower chamber.
22. The accumulator of claim 21 wherein the low pressure inlet port
extends through an opening in the top or an opening in the upper
shell into the upper chamber.
23. The accumulator of claim 21 wherein a high temperature
refrigerant flows through the inner tubes and a low temperature
refrigerant flows through the outer tubes in a heat exchange
relationship.
24. The accumulator of claim 21 wherein the inner tubes are
serially connected.
25. The accumulator of claim 21 wherein the inner tubes are
connected in parallel.
26. The accumulator of claim 21 wherein the heat exchanger
comprises a first, second, third, and fourth coaxial tube, each
coaxial tube having a first, second, third, and fourth outer tube,
a first, second, third, and fourth inner tube, each inner tube
having an upper inner tube end and a lower inner tube end, wherein
the first upper inner tube end is connected to the second upper
inner tube end, the second lower inner tube end is connected to the
third lower inner tube end, and the third upper inner tube end is
connected to the fourth upper inner tube end.
27. The accumulator of claim 26 wherein a high temperature
refrigerant enters the first lower inner tube end, flows through
the four inner tubes, and exits the fourth lower inner tube end and
a low temperature refrigerant flows through the four outer tubes in
a heat exchange relationship with the high temperature refrigerant
flowing through the inner tubes.
28. An accumulator for an air conditioning system or a
refrigeration system comprising: a housing, a top, and a bottom,
said housing, top and bottom forming a closed chamber; and a heat
exchanger disposed in the chamber comprising a plurality of coaxial
tubes, each coaxial tube having an outer tube enclosed in the
housing and an inner tube extending through the top, chamber and
bottom, wherein said inner tubes are fluidly connected to allow a
high temperature refrigerant to flow therethrouh while a low
temperature refrigerant simultaneously flows through the outer
tubes in a heat exchange relationship.
29. A method of operating an air conditioning or refrigeration
system comprising: conveying condensed refrigerant through a high
pressure inlet port into an accumulator having an internal heat
exchanger, said heat exchanger comprising a plurality of coaxial
tubes, each coaxial tube further comprising an outer tube and an
inner tube disposed within the outer tube, wherein said inner tubes
extend through the accumulator and are fluidly connected; conveying
the condensed refrigerant through the inner tubes; discharging the
condensed refrigerant from the inner tubes and accumulator through
a high pressure outlet port; evaporating the refrigerant; conveying
the evaporated refrigerant into the accumulator through a low
pressure inlet port; conveying the evaporated refrigerant in the
accumulator through the outer tubes of the heat exchanger in a heat
exchange relationship with the condensed refrigerant flowing
through the inner tubes; conveying the evaporated refrigerant into
a vapor conduit tube; discharging the evaporated refrigerant from
the vapor conduit tube and accumulator; and conveying the
evaporated refrigerant to a compressor.
30. A method of cooling a high temperature liquid refrigerant in an
air conditioning or refrigeration system comprising: conveying the
high temperature refrigerant through a heat exchanger disposed in
an accumulator while simultaneously conveying a low temperature
refrigerant through the heat exchanger, said heat exchanger
comprising at least one tube defining at least one high temperature
channel therethrough, and at least one low temperature channel
therethrough, wherein the high temperature refrigerant flows
through the high temperature channel in a heat exchange
relationship with low temperature refrigerant flowing through the
low temperature channel.
31. A method for cooling a high temperature refrigerant discharged
from a condenser in an air conditioning or refrigeration system
comprising: conveying the high temperature refrigerant through a
heat exchanger disposed in an accumulator while simultaneously
conveying a low temperature refrigerant through the heat exchanger,
said heat exchanger comprising a helically shaped coaxial tube
having an outer tube and an inner tube disposed within said outer
tube, wherein the high temperature refrigerant flows through the
outer tube and the low temperature refrigerant flows through the
inner tube in a heat exchange relationship.
32. A method of cooling a high temperature refrigerant in an air
conditioning or refrigeration system comprising: conveying the high
temperature refrigerant through a heat exchanger while
simultaneously conveying a low temperature refrigerant through the
heat exchanger, the heat exchanger comprising a plurality of
coaxial tubes, each coaxial tube further comprising an outer tube
disposed entirely within the accumulator and an inner tube
positioned in the outer tube, said inner tube extending through the
accumulator, wherein the high temperature refrigerant flows through
the inner tubes and the low temperature refrigerant flows through
the outer tubes.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to an accumulator with an integral
heat exchanger for use in an air conditioning or refrigeration
system. In particular, the heat exchanger is positioned inside the
accumulator such that liquid refrigerant from the high pressure,
high temperature side of the system and gaseous refrigerant from
the low pressure, low temperature side of system simultaneously
flow through the heat exchanger in a heat exchange relationship.
The accumulator of the present invention may be used with a variety
of refrigerants including R134a and carbon dioxide, despite the
higher operating pressures inherent in a system using carbon
dioxide as the refrigerant.
[0002] A basic refrigeration or air conditioning system has a
compressor, a condenser, an expansion device, and an evaporator.
These components are generally serially connected via conduit or
piping and are well known in the art. During operation of the
system, the compressor acts on relatively cool gaseous refrigerant
to raise the temperature and pressure of the refrigerant. From the
compressor, the high temperature, high pressure gaseous refrigerant
flows into the condenser where it is cooled and exits the condenser
as a high pressure liquid refrigerant. The high pressure liquid
refrigerant then flows to an expansion device, which controls the
amount of refrigerant entering into the evaporator. The expansion
device lowers the pressure of the liquid refrigerant before
allowing the refrigerant to flow into the evaporator. In the
evaporator, the low pressure, low temperature refrigerant absorbs
heat from the surrounding area and exits the evaporator as a
saturated vapor having essentially the same pressure as when it
entered the evaporator. The suction of the compressor then draws
the gaseous refrigerant back to the compressor where the cycle
begins again.
[0003] In a typical air conditioning or refrigeration system, it is
necessary to prevent liquid from passing from the evaporator into
the compressor in order to avoid damage to the compressor. When
liquid refrigerant enters a compressor, it is known as slugging.
Slugging reduces the overall efficiency of the compressor and can
also damage the compressor. It is well known in the art to mount a
suction line or low pressure side accumulator between the
evaporator and compressor. Such suction line accumulators act to
separate the liquid and gaseous phases of the refrigerant flowing
from the evaporator. The liquid portion of the refrigerant will
settle to the bottom of the accumulator while the gaseous phase
will rise to the top of the accumulator and will be suctioned out
of the accumulator by the compressor.
[0004] It is also known in the art to have an accumulator with a
heat exchanger arranged on both the high pressure and low pressure
sides of an air conditioning or refrigeration system. FIG. 1 is a
schematic of a system having an accumulator arranged on both the
high pressure and low pressure sides of the system. In general,
high pressure, high temperature refrigerant exits a compressor 1
and flows into a condenser 3. The high temperature liquid
refrigerant exits the condenser and flows into a heat exchanger
located in an accumulator 5. The refrigerant is discharged from the
accumulator and flows into an expansion device 7 and subsequently
into an evaporator 9.
[0005] At the same time, low temperature, low pressure refrigerant
flowing from the evaporator 7 enters the accumulator and the liquid
phase settles to the bottom of the accumulator, and the gaseous
phase rises. The low temperature gaseous refrigerant then flows
through the heat exchanger where it comes in contact with the high
pressure, high temperature liquid refrigerant from the condenser in
a heat exchange relationship. The high pressure liquid from the
condenser 3 is then cooled by the low pressure, low temperature
gaseous refrigerant running simultaneously through the heat
exchanger. As a result, the liquid refrigerant flowing from the
condenser 3 to the evaporator is cooled and can thereby absorb more
heat as it flows through the evaporator 7. The gaseous refrigerant
exiting the low pressure side of heat exchanger is higher in
temperature having absorbed heat from the high pressure, high
temperature liquid refrigerant. As a result, any liquid refrigerant
that may remain in the low pressure, low temperature refrigerant
will be converted into a gas in the heat exchanger thereby reducing
the risk of having liquid flow into the compressor.
[0006] U.S. Pat. Nos. 5,622,055, 5,245,833, 4,488,413, and
4,217,765 disclose accumulators with internal heat exchangers. In
these patents, high pressure, high temperature refrigerant from the
condenser is cooled as it flows through a tube that is sitting in a
pool of low temperature liquid refrigerant that has been discharged
from the evaporator and collected in the accumulator.
[0007] GB Patent No. 2316738B also discloses a low pressure side
accumulator with an internal heat exchanger. The accumulator is
divided into an upper and lower chamber. The heat transfer unit,
two serially connected tubes, is housed in the lower chamber. High
temperature, high pressure refrigerant flowing from the condenser
enters one end of the tubes and exits the other end and then flows
to an expansion device evaporator. At the same time, low pressure,
low temperature refrigerant from the evaporator is discharged into
the upper chamber. The refrigerant in the upper chamber is drawn
into the lower chamber where it flows through the lower chamber in
a heat exchange relationship with high pressure, high temperature
refrigerant flowing through the tubes before being discharged from
the accumulator and drawn back to the compressor.
[0008] U.S. Pat. Nos. 5,457,966 and 5,289,699 disclose a high
pressure side accumulator with internal heat exchanger. In one
embodiment, the heat exchanger comprises an outer shell with right
and left end plates and an outer tube with a cutaway portion
located within the shell. An inner tube is housed within the outer
tube and extends through the shell and both end plates. In
operation, high pressure, high temperature liquid refrigerant from
the condenser enters an inlet line, which flows into the outer
tube. The liquid refrigerant flows through the outer tube and into
the shell at the cut away portion. The liquid refrigerant is
discharged from the shell through an outlet line. At the same time,
low pressure, low temperature refrigerant from the evaporator
enters the smaller tube and flows through the inner tube in a heat
exchange relationship with the high pressure, high temperature
refrigerant before flowing back to the compressor.
[0009] In a second embodiment, the heat exchanger housed within the
shell comprises a small oval shaped tube affixed to one side of a
large tube. The larger tube extends through the entire length of
the shell. High pressure, high temperature liquid refrigerant from
the condenser enters one end of the oval shaped tube and exits the
other end and flows into the shell. Liquid refrigerant exits the
shell through an outlet line and flows to the evaporator.
Simultaneously, low pressure, low temperature refrigerant flows
from the evaporator through the large tube in a heat exchange
relationship with the high pressure, high temperature refrigerant.
The low pressure, low temperature refrigerant exiting the larger
tube flows back to the compressor. A third embodiment is similar to
the second embodiment except that the smaller tube is spirally
wrapped around the outside of the larger tube.
[0010] U.S. Pat. No. 3,830,077 discloses a heat exchanger for use
in a vehicle, which is connected between the evaporator and
compressor. The heat exchanger comprises an outer shell with low
pressure, low temperature inlet and outlet lines and at least one
heat exchange coil, with an inlet end an outlet end both extending
through the shell. In operation, low pressure, low temperature
refrigerant enters the inlet line, flows through the shell, exits
the outlet line and flows back to the compressor. At the same time
a high temperature vehicle fluid flows through the coil in a heat
exchange relationship with the low temperature, low pressure
refrigerant. The patent does not specifically disclose connecting
the heat exchange coil to the high pressure, high temperature side
of the air conditioning system.
[0011] Finally, published EP Patent Application No. EP 0837291A2
discloses the use of a sub cooling circuit to cool high pressure,
high temperature carbon dioxide refrigerant in a vehicle air
conditioning system. The sub cooling circuit is located between the
condenser and main expansion device and comprises a subpressure
reducer and a heat exchanger. In operation, the high pressure, high
temperature carbon dioxide refrigerant from the condenser is split
into two flows, the first flow flows into the sub cooling circuit
where it is cooled by passing through the pressure reducer before
flowing through heat exchanger. The second flow of refrigerant
passes directly through the heat exchanger where it is cooled by
the first flow.
[0012] The application discloses two different types of heat
exchangers. The first heat exchanger comprises a double circular
tube structure which has an inner tube surrounded by an outer tube
with fins separating the tubes. Lower temperature carbon dioxide
refrigerant flows through the inner tube in a heat exchange
relationship with higher temperature refrigerant flowing through
the outer tube.
[0013] The second heat exchanger comprises a spiral tube structure
formed from two tubes soldered together. Each tube is an extruded
aluminum strip with an upper row of holes and a lower row of holes.
High temperature carbon dioxide refrigerant flows through both rows
of holes in one tube while lower temperature refrigerant flows
through both rows of holes in the second tube in a heat exchange
relationship. EP Patent Application No. 0837291A2 does not disclose
having high temperature and low temperature refrigerant flowing
through one tube at the same time. Furthermore, EP Patent
Application No. 0837291A2 does not disclose combining the heat
exchanger in the sub cooling circuit into an accumulator. Thus, the
disclosed air conditioning system is more complicated than
necessary having an extra sub cooling circuit, which can be
eliminated by the present invention.
[0014] While the above accumulators and heat exchangers are
suitable for their intended purpose, it is believed that there is a
demand in the industry for an improved accumulator with an internal
heat exchanger, especially one that can withstand the higher
pressure requirements of an air conditioning or refrigeration
system employing carbon dioxide as a refrigerant. It is further
believed that there is a demand for an improved accumulator with an
internal heat exchanger that is compact, easily assembled, lighter
weight, and less costly to manufacture, but yet provides a high
level of efficiency.
BRIEF SUMMARY OF THE INVENTION
[0015] The present invention provides an improved accumulator for
use in an air conditioning or refrigeration system, and in
particular, provides an accumulator with an improved compact heat
exchanger. The improved accumulator may be used in existing air
conditioning and refrigeration systems utilizing R134a as the
refrigerant as well as in newer systems utilizing carbon dioxide as
the refrigerant. The improved accumulator can easily withstand the
higher pressures resulting from the use of carbon dioxide
refrigerant.
[0016] The improved heat exchanger has a high heat transfer
efficiency resulting in an increase in the coefficient of
performance (COP) for the air conditioning or refrigeration system.
As a result, the air conditioning or refrigeration system has
greater cooling capacity. This greater cooling capacity allows for
more rapid "pull down" or cooling when the air conditioning or
refrigeration system is first started.
[0017] In addition, the accumulator of the present invention
provides increased protection against slugging in the compressor by
ensuring that any liquid remaining in the refrigerant being drawn
back into the compressor is vaporized in the heat exchanger.
Finally, the heat exchanger of the present invention is easy to
manufacture and is lighter in weight because all of the components
may be made from aluminum.
[0018] According to one embodiment of the present invention, the
accumulator has a housing with a top and a bottom such that the
housing, top, and bottom form a chamber. The accumulator has a high
pressure outlet port and a low pressure inlet port extending
through the top and into the chamber, and a high pressure inlet
port and a low pressure outlet port which are external to the
housing. A vapor conduit tube and a heat exchanger are disposed in
the chamber. The heat exchanger comprises at least one tube having
a low temperature channel and a high temperature channel, each
channel extending through the interior of the tube. At one end of
the tube, the high temperature channel is connected to the high
pressure inlet port and the low temperature channel is connected to
the low pressure outlet port. At the other end of the tube, the
high temperature channel is connected to the high pressure outlet
port and the low temperature channel is connected to the vapor
conduit tube.
[0019] In operation, high pressure, high temperature refrigerant
from the condenser enters the accumulator and then the heat
exchanger through the high pressure inlet port. The high pressure,
high temperature refrigerant flows through the high temperature
channel and exits the heat exchanger and the accumulator through
the high pressure outlet port. Simultaneously, low pressure, low
temperature refrigerant flows through the low temperature inlet
port into the chamber and is conveyed through the vapor conduit
tube to the heat exchanger. The low pressure, low temperature
refrigerant then flows through the low temperature channel in a
heat exchange relationship with the high pressure, high temperature
refrigerant flowing through high temperature channel thereby
cooling the high pressure, high temperature refrigerant.
[0020] In a second embodiment of the present invention, the
accumulator likewise has a housing with a top and bottom such that
the housing, top and bottom form an internal chamber. High
pressure, high temperature inlet and outlet ports as well as low
temperature inlet and outlet ports extend through the top of the
accumulator into the chamber. A vapor conduit tube and a heat
exchanger are disposed in the chamber. The heat exchanger comprises
a coaxial tube having an outer tube and an inner tube disposed
within the outer tube. At one end of the coaxial tube, the high
pressure, high temperature inlet port is attached to the inner tube
and the low pressure, low temperature outlet port is attached to
the outer tube. At the other end of the coaxial tube the high
pressure, high temperature outlet port is attached to inner tube
and the vapor conduit tube is attached to the outer tube.
[0021] In operation, high pressure, high temperature refrigerant
from the condenser enters the accumulator and then the heat
exchanger through the high pressure inlet port. The high pressure,
high temperature refrigerant flows through the inner tube and exits
the heat exchanger and the accumulator through the high pressure
outlet port. Simultaneously, low pressure, low temperature
refrigerant flows through the low temperature inlet port into the
chamber and is conveyed through the vapor conduit tube to the heat
exchanger. The low pressure, low temperature refrigerant then flows
through the outer tube in a heat exchange relationship with the
high pressure, high temperature refrigerant flowing through the
inner tube thereby cooling the high pressure, high temperature
refrigerant.
[0022] In a third embodiment of the present invention, the
accumulator has a housing, a top, and a bottom such that the
housing, top, and bottom form a chamber. The chamber is divided
into an upper chamber and a lower chamber by a separator. The
accumulator further has low pressure inlet port and a vapor conduit
extending through the top, the upper chamber and the separator
before terminating in the lower chamber. The internal heat
exchanger comprises a plurality of coaxial tubes, each coaxial tube
having an outer tube and an inner tube disposed within the outer
tube. The inner tubes of the coaxial tubes extend through the top,
upper chamber, separator, lower chamber and bottom of the
accumulator. The outer tubes extend from the top in the upper
chamber through the separator and terminate in the lower chamber.
The inner tubes are interconnected to allow refrigerant to
circulate through each inner tube.
[0023] In operation, the high pressure, high temperature
refrigerant flows from the condenser and enters the connected inner
tubes. The refrigerant flows through the tubes before being
discharged from the accumulator. At the same time, low pressure,
low temperature refrigerant from the evaporator enters the low
pressure inlet port and flows into the accumulator. The low
pressure, low temperature refrigerant then flows through the outer
tubes in a heat exchange relationship with the refrigerant flowing
through the inner tubes and is deposited in the lower chamber. The
low pressure, low temperature refrigerant is then drawn into the
vapor conduit tube and is discharged from the accumulator.
[0024] Further features and advantages of the present invention
will be apparent upon reviewing the following detailed description
and accompanying drawings.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0025] FIG. 1 is a schematic of an air conditioning system using
the accumulator-heat exchanger of the present invention;
[0026] FIG. 2 is an exploded view of a first embodiment of an
accumulator of the present invention;
[0027] FIG. 3 is a cross-sectional view of the accumulator of FIG.
2 taken along line 1-1;
[0028] FIG. 4 is a top cross-sectional view of the accumulator of
FIG. 3 taken along line 2-2;
[0029] FIG. 5 is a cross-sectional view of one embodiment of a heat
exchanger of the present invention;
[0030] FIG. 6 is an elevational view of a heat exchanger of the
present invention;
[0031] FIG. 7 is a cross-sectional view of the heat exchanger of
FIG. 6 taken along line 3-3;
[0032] FIG. 8 is a plan view of a second embodiment of an
accumulator of the present invention;
[0033] FIG. 9 is a cross-sectional view of the accumulator of FIG.
8 taken along line 4-4;
[0034] FIG. 10 is a cross-sectional view of the accumulator of FIG.
8 taken along line 5-5;
[0035] FIG. 11 is a partial exploded view of the second embodiment
of the present invention;
[0036] FIG. 12 is a cross-sectional view of one end of the heat
exchanger of the second embodiment of the present invention;
[0037] FIG. 13. is an enlarged cross-sectional view of a coaxial
tube used in the heat exchanger of the second embodiment of the
present invention;
[0038] FIG. 14 is a cut-away view of a third embodiment of an
accumulator of the present invention;
[0039] FIG. 15 is a cross-sectional view of the accumulator of FIG.
14 taken along line 6-6;
[0040] FIG. 16 is a cross-sectional view of a coaxial tube used in
the heat exchanger of FIG. 14 taken along line 7-7.
[0041] FIG. 17 is an exploded view of the accumulator of FIG.
14.
DETAILED DESCRIPTION OF THE INVENTION
[0042] Referring to FIGS. 2 and 3, the accumulator 15 has a housing
17 with sidewalls 19, a bottom wall 21, and a cover 23 comprising a
top 25 and sidewalls 27. The housing 17 and the bottom wall 21 are
preferably integrally formed to form the lower portion of the
accumulator. The cover 23 is separately formed from the housing and
forms the upper portion of the accumulator. While the accumulator
shown in FIGS. 2 and 3 is cylindrical in shape, the accumulator of
the present invention may have any shape, including square,
rectangular or ellipsoidal.
[0043] The housing 17 and the integrally formed bottom wall 21 are
generally affixed to cover the 23 in an abutting relationship at an
overlapping juncture 29 to form a fluid tight or sealed internal
chamber 31. Welding, soldering, or brazing may be used to affix the
housing and cover. The cover and housing may be formed from any
material that will satisfy the structural demands placed on the
accumulator. Suitable materials include, but are not limited to,
aluminum, stainless steel, and copper. In a preferred embodiment,
the accumulator cover and housing are aluminum.
[0044] The top of the cover has two openings 33 and 35 for
receiving a low pressure inlet port 37 and a high pressure outlet
port 39 respectively. The openings 33 and 35 may be circular,
elliptical, square, rectangular, or any other desired shape. The
low pressure inlet port 37 and high pressure outlet port 39
generally correspond in shape to the openings in the top of the
cover. In a preferred embodiment, the openings 33 and 35 are
circular and low pressure inlet port and high pressure outlet ports
are cylindrical in shape.
[0045] In addition, the accumulator has a low pressure outlet port
41 and a high pressure inlet port 43. Preferably, high pressure
inlet port and low pressure outlet port are cylindrical but may
have any shape desired. The high pressure inlet and outlet ports
and the low pressure inlet and out ports may be formed from
aluminum, stainless steel, copper or any other suitable material.
Preferably the inlet and outlet ports are formed from aluminum.
[0046] The low pressure outlet port is affixed to the outer portion
of the sidewall 27 by brazing, soldering welding, or the like. The
high pressure inlet port is supported by a support 45 mounted on
the top of the cover. The support 45 is generally rectangular in
shape with one end 47 affixed to the top of the cover, and the
opposite end 49 affixed to the high pressure inlet port. The end 49
attached to the high pressure inlet port will generally conform to
the shape of the port. As shown in FIG. 2, the high pressure inlet
port 43 is cylindrical and thus the support has a circular shaped
end, which conforms directly to the radius of curvature of the
cylindrical port. The support may be attached to the cover and the
high pressure outlet port by soldering, brazing, welding, or any
other suitable method.
[0047] Below the support, an inverted U-shaped opening 51 is formed
in the sidewall of the cover. The housing 17 has a corresponding
U-shaped opening 53 in the upper portion of the sidewall 19. When
the housing and the cover are affixed the opening 51 and the
opening 53 align to from a generally rectangular opening through
which a portion of a heat exchanger 55 passes and is connected to
the low pressure outlet port 41 and the high pressure inlet port
43. The housing 17 further has a sump 57 formed in the center of
the bottom wall 21. The sump 57 collects and stores oil, which is
used to lubricate the components of the air conditioning or
refrigeration system.
[0048] A vapor conduit 59 with a vapor inlet end 61 and a vapor
outlet end 63 having a cap 65 is positioned inside the housing.
Preferably, vapor the conduit is an aluminum cylindrical J-shaped
tube or J-tube. However, the vapor conduit may have any other
desirable shape, including linear, and may be formed from any
suitable materials such as stainless steel or copper. The vapor
outlet end 63 extends vertically into the lower portion of the
housing and is curved at its lower most point 67. The curved
portion of the J-tube extends into the housing adjacent the bottom
wall. The J-tube 59 extends upwardly from the lower most point to
the inlet end 61. The J-tube 59 further has one or more openings 69
in the curved portion of the tube, which allow small amounts of oil
to be drawn out of the sump and into the J-tube where the oil is
mixed with gaseous refrigerant. The refrigerant/oil mixture
eventually exits the accumulator through the low pressure outlet
port 41 and flows back to the compressor providing needed
lubrication for the compressor and other components of the
system.
[0049] As shown in FIGS. 2 and 3, the accumulator may also have a
deflector positioned in the housing. The deflector 71 assists in
separating liquid and gaseous refrigerant entering the accumulator
through the low pressure inlet port from the evaporator. Low
pressure, low temperature refrigerant entering the accumulator
comes into contact with the deflector causing any liquid
refrigerant to flow down the sides of the accumulator thereby
preventing liquid refrigerant from entering the inlet end 61 of the
J-tube. Gaseous refrigerant rises and is allowed to enter the inlet
end 61 of the J-tube, which is positioned underneath the deflector.
The deflector can be made of any suitable material including
aluminum, copper, stainless steel, or plastic, and may have a
variety of shapes including conical, dome, disc or cup. In a
preferred embodiment, the deflector is dome shaped and formed from
aluminum. The deflector further has an opening through which the
outlet end of the J-tube passes. The J-tube may be soldered, brazed
or welded to the deflector at the point the outlet end passes
through the deflector to from a liquid-tight seal.
[0050] Referring now to FIG. 6, the heat exchanger 55 is formed
separately from the accumulator cover and housing and is generally
an extruded tube with interior 73, exterior 75, height H and width
W. In a preferred embodiment, the heat exchanger is a rectangular
shaped flat extruded aluminum tube. However, the tube may have any
shape including circular or elliptical, and may be formed from any
other suitable material such as stainless steel, copper or plastic.
Preferably, the heat exchanger has a spiral configuration with an
internal end 77 and an external end 79. As shown in FIG. 5, the
heat exchanger 55 further has at least two adjacent channels, a
high temperature channel 81 and a low temperature channel 83
extending through the interior 73 of the tube. As shown in FIGS. 6
and 7, the channels preferably comprise two rows of microchannels
85. In a preferred embodiment, a section of low temperature channel
83 is removed from the internal and external ends of the heat
exchanger tube. As a result, the high temperature channel protrudes
beyond the low temperature channel and forms a tongue 95 with
height H' and width W on each end of the heat exchanger.
[0051] Alternatively, the heat exchanger may be an extruded tube
having three or more channels, an upper channel, a middle channel
and a lower channel. In such a heat exchanger, high pressure, high
temperature refrigerant from the condenser may flow through the
middle row of microchannels while low pressure, low temperature
refrigerant from the evaporator flows through the upper and lower
rows of microchannels in the opposite direction.
[0052] FIG. 4 is a top sectional view of the heat exchanger having
two rows of microchannels as it is positioned in the accumulator.
The high pressure outlet port 39 and the vapor outlet end 63 of the
J-tube are attached to the interior end of the heat exchanger. The
low-pressure outlet port 41 and the high-pressure inlet port 43 are
attached to the exterior end of the heat exchanger. The
low-pressure inlet port 37 is not connected to the heat
exchanger.
[0053] As shown in FIG. 2, low pressure outlet port 41 has an upper
end 97 and a lower end 99 with a cap 101. The lower end 99 further
has an opening 103 for receiving the low temperature channel of the
heat exchanger tube. The opening 103 conforms generally to the
height H and width W of the heat exchanger. The low pressure outlet
port is attached to the heat exchanger by sliding the port over the
tongue 95 and forming an abutting relationship with the low
temperature channel. The J-tube 59 likewise has an opening in the
outlet end 63 of the tube for receiving the heat exchanger. The
opening in the upper end of the J-tube is identical to that of the
low pressure outlet port, so the J-tube attaches to the heat
exchanger in the same manner as the low pressure outlet port. Both
the low pressure outlet port 41 and the J-tube 59 may be attached
to the heat exchanger by soldering, brazing, welding, or any other
suitable method.
[0054] High pressure inlet port 43 and high pressure outlet port 39
likewise have upper ends 105 and lower ends 107 with caps 109. High
pressure inlet and outlet ports also have openings 110 in the lower
end of the ports for receiving the heat exchanger. In general, the
openings 110 conform to the width W and H' of the tongue 95, and
are D-shaped, High pressure inlet and outlet ports are attached to
the heat exchanger by inserting the tongues 95 into the openings
110. Both the high pressure inlet and outlet ports may be attached
to the tongue by soldering, brazing, welding or any other suitable
method.
[0055] In operation, the accumulator 15 is placed into an air
conditioning or refrigeration system as shown in FIG. 1. The
refrigerant flow through the system is the same as discussed with
respect to FIG. 1. Therefore, only the flow through the accumulator
will be specifically discussed. Arrows have been added to FIGS. 2-4
to illustrate the flow of refrigerant through the accumulator and
the heat exchanger. From the condenser, the high temperature liquid
refrigerant flows into the accumulator through the high pressure
inlet port 43, and then into the heat exchanger 55 where it flows
in a clockwise direction through the high temperature channel 81
before being discharged from the accumulator at the high pressure
outlet port 39. After being discharged from the accumulator, the
refrigerant flows to an expansion device, which meters the amount
of fluid flowing into the evaporator. Simultaneously, the primarily
gaseous refrigerant exits the evaporator and flows into the low
pressure inlet port 37 of the accumulator. The refrigerant hits the
dome shaped deflector 71, and any liquid refrigerant settles to the
bottom of the accumulator. The gaseous refrigerant rises and enters
the vapor inlet end 61 of the J-tube 59 and then flows through the
J-tube and out the vapor outlet end 63 into the low temperature
channel 83 of the heat exchanger. The low pressure, low temperature
gaseous refrigerant flows in a counterclockwise direction through
the low temperature channel of the heat exchanger where it absorbs
heat from the high pressure, high temperature refrigerant passing
through the high temperature channel. The low pressure, low
temperature refrigerant vapor is then drawn out of the accumulator
through the low pressure outlet port 41 and flows to the
compressor.
[0056] A second embodiment of the accumulator of the present
invention is shown in FIGS. 8-12. Referring to FIGS. 8-11, the
accumulator 115 has a housing 117 with sidewalls 119, a bottom wall
121, and a cover 123 having a top 125 and sidewalls 127. The
housing 117 and the bottom wall 121 are preferably integrally
formed. Similar to the previous embodiment, a sump 128 is formed in
the bottom wall of the housing in the housing. The sump 128 is
similar in design to the sump previously discussed, and therefore,
will not be discussed in further detail. The cover is separately
formed from the housing and forms the upper portion of the
accumulator. While the accumulator shown in FIGS. 8-11 is
cylindrical in shape, the accumulator of the present invention may
have any shape, including square, rectangular or ellipsoidal.
[0057] The cover 123 generally fits on top of the housing and
integrally formed bottom wall 121 to form a fluid tight or sealed
internal chamber 129. Welding, soldering, or brazing may be used to
affix the housing and cover. The cover and housing may be formed
from any material that will satisfy the structural demands placed
on the accumulator. Suitable materials include, but are not limited
to, aluminum, stainless steel, and copper. In a preferred
embodiment, the accumulator cover and housing are aluminum.
[0058] As shown in FIGS. 10 and 11, the accumulator has a high
pressure inlet port 131, a high pressure outlet port 135, a low
pressure inlet port 137, and a low pressure outlet port 139.
Referring to FIG. 10, the accumulator further has a vapor conduit
or J-tube 141 with an inlet end 143 and an outlet end 145
positioned inside the housing. The inlet and outlet ports as well
as the J-tube may have any desired shape, and may be formed from
any suitable material including but not limited to aluminum,
stainless, steel, or copper. Preferably inlet and outlet ports and
J-tube are cylindrical in shape and are formed from aluminum.
[0059] The inlet end of the J-tube extends vertically into the
lower portion of the housing and is curved at its lower most point
147. The J-tube extends upwardly from the lower most point to its
outlet end 145. The J-tube 141 further has one or more openings
(not shown) in the curved portion of the conduit to allow for
lubricating oil to be drawn into the system as previously discussed
with respect to the first embodiment. As shown in FIG. 10, both the
inlet and outlet ends 143 and 145 of the J-tube are positioned
underneath a dome shaped deflector 149. The deflector is similar to
deflector 71 shown in FIGS. 2 and 3, and therefore, will not be
discussed in further detail.
[0060] A heat exchanger 151 is also disposed in the housing.
Referring now to FIGS. 10-12, the heat exchanger comprises an
extruded coaxial tube with an inner tube 153 having an upper end
155 and a lower end 157 and an outer tube 159 having corresponding
upper and lower ends 161 and 163. As shown in FIG. 13, an enlarged
cross-sectional view of the coaxial tube, the outer tube has an
outer wall 162 and an inner wall 164, and the inner tube has outer
wall 165 and inner wall 167. Fins or separators 169 extend radially
from the outer wall 165 of the inner tube to the inner wall 164 of
the outer tube. Any number of fins may be used separate the inner
and outer tubes. However, the greater the number of fins, the more
difficult it is to spirally shape the coaxial tube. While the
coaxial tube in FIGS. 10-12 is preferably spirally shaped, the
coaxial tube may be straight or have other configurations as
desired. The inner and outer tubes as well as the fins may be
formed from aluminum, copper, or stainless steel or any other
suitable material. Preferably, the inner and outer tubes are
aluminum.
[0061] As shown in FIG. 12, a cross-sectional view of each end of
the coaxial tube, a portion of the upper and lower ends of the
outer tube 159 is removed so that sections 166 of the inner tube
extend beyond the upper and lower ends of the outer tube. A cap 170
is placed on each end 168 of the outer tube in order to seal the
tube and prevent refrigerant from flowing out the ends.
[0062] Referring now to FIGS. 10 and 11, the high pressure inlet
port 131 extends through the cover of the accumulator, passes
through an opening 171 in the deflector and extends down into the
housing where it is attached to the lower end of the inner tube.
The high pressure outlet port 135 extends through the top of the
accumulator, passes through an opening 173 in the deflector and is
attached to the upper end 155 of the inner tube. Preferably, the
high pressure inlet and outlet ports are cylindrical and have a
diameter that is either slightly larger or slightly smaller than
the diameter of the inner tube such that inner tube and high
pressure inlet and outlet ports may be matingly engaged. Welding,
soldering, brazing or any other suitable method may be used to form
a permanent seal between the high pressure inlet and outlet ports
and the lower and upper ends of the inner tube.
[0063] The J-tube 141 is attached at its outlet end 145 to the
upper end 161 of the outer tube. As shown in FIG. 12, the outer
tube has an opening 175 in the side of the upper and lower ends of
the tube. The outlet end 145 of the J-tube has a diameter slightly
less than the diameter of opening 175 and is capable of mating
engagement with opening 175 of the outer tube. The outlet end of
the J-tube and the upper end of the outer tube are soldered, brazed
or welded together to form a liquid tight seal. The low pressure
outlet port 139 extends through the top of the accumulator, passes
through an opening 177 in the deflector and extends vertically into
the lower portion of the housing. The low pressure outlet port 139
is attached to the lower end 163 of outer tube in the same manner
the J-tube is attached to the outer tube.
[0064] In operation, the accumulator 115 is positioned in an air
conditioning or refrigeration system as shown in FIG. 1. Again, the
flow of refrigerant through the system is the same as discussed
with respect to FIG. 1. Arrows have been added to FIGS. 10 and 11
to indicate the direction of flow of the refrigerant through the
accumulator. Therefore, only the flow through the accumulator will
be discussed. High pressure, high temperature liquid refrigerant
from the condenser enters the high pressure inlet port 131 of the
accumulator and flows through the inner tube 153 of the heat
exchanger in a counter-clockwise direction. The high pressure, high
temperature refrigerant is then discharged from the accumulator
through high pressure outlet port 135. At the same time, low
pressure, low temperature refrigerant exiting the evaporator enters
the accumulator through the low pressure inlet port 137 contacts
the deflector 149 and flows into the accumulator housing. The
gaseous refrigerant rises and enters the inlet end 143 of the
J-tube and flows into the upper end 161 of the outer tube. The low
temperature, low pressure refrigerant flows through the outer tube
in a clockwise direction absorbing heat from the high pressure,
high temperature refrigerant, thereby lowering the temperature of
the high pressure, high temperature refrigerant. The low pressure,
low temperature refrigerant is discharged from the accumulator
through the low pressure outlet port 139 and drawn back to the
compressor.
[0065] A third embodiment of the accumulator is shown in FIGS.
14-17. The accumulator 180 has a top 181, an upper housing 183 with
sidewalls 185, a separator 187, a lower housing 189 with sidewalls
191, and a bottom 193. The top, upper housing, separator, lower
housing, and bottom form a fluid tight or sealed internal chamber
having an upper chamber 197 and a lower chamber 199. The separator
187 further has an upper surface 201, which forms the bottom of the
upper chamber, and a lower surface 203, which forms the top of the
lower chamber 199. Welding, brazing, soldering or any other
suitable method may be used to join the top, the upper housing, the
separator, the lower housing and the bottom to form the
accumulator. The accumulator may have any shape, but is preferably
cylindrical in shape as shown in FIGS. 14, 15, and 17. The top,
upper housing, separator, lower housing, and bottom, may be formed
from any material that will satisfy the structural demands placed
on the accumulator. Suitable materials include, but are not limited
to, aluminum, stainless steel, and copper. In a preferred
embodiment, the top, upper housing, separator, lower housing and
bottom are aluminum.
[0066] As shown in FIG. 17, a low pressure inlet port 205 has an
upper end 207 and a lower end 208. The upper end 207 passes through
an opening 209 in top of the housing and allows refrigerant flowing
from the evaporator to enter the upper chamber of the accumulator
housing. The lower end 208 may be slightly curved to direct the
flow of refrigerant into the accumulator. Alternatively, the low
pressure inlet port 205 may pass through an opening 211 in the
sidewall 185 of the housing as shown in FIG. 14. The low pressure
inlet port may have any desired shape, and maybe formed from
aluminum, stainless steel, copper or any other suitable material.
Preferably, the low pressure inlet port is a cylindrical aluminum
tube.
[0067] As shown in FIGS. 14, 15 and 17, a vapor conduit 213 passes
through an opening 215 in the center of the top down into the upper
chamber, and through an opening 217 in the separator, and
terminates in the lower chamber. The vapor conduit 213 has an inlet
end 219, an outlet end 221, and a bead 222 formed adjacent the
inlet end. The bead 222 abuts the lower surface of the separator
and forms a fluid tight seal between the vapor conduit tube and the
lower surface of the separator. In the embodiment shown in FIG. 14,
the inlet end of the vapor conduit 213 abuts the bottom 193 such
that a vapor tight seal is formed. As a result, the vapor conduit
has a first opening 214 directly beneath the separator. Low
pressure, low temperature vapor deposited in the lower chamber
enters the vapor conduit through opening 214 and flows out of the
accumulator at the outlet end 221 of the vapor conduit. A second
opening 216 is formed in the vapor conduit directly above the
separator. The opening 216 allows oil, which is collected and
stored in the upper chamber, to flow into the vapor conduit where
it mixes with the refrigerant and provides lubrication for the
compressor and other parts of the overall system.
[0068] In another embodiment shown in FIG. 15, the inlet end 219 of
the vapor conduit terminates above the bottom 193. Low pressure,
low temperature vapor in the lower chamber flows into the inlet end
219 of the vapor conduit. Oil stored in the upper chamber enters
the vapor conduit through an opening (not shown) in the conduit
directly above the separator. The vapor conduit is preferably a
cylindrical aluminum tube, but may have any desired shape, and may
be formed from other suitable materials including stainless steel
and copper.
[0069] Accumulator 180 further has a heat exchanger disposed
primarily in the upper chamber. A preferred embodiment of the heat
exchanger comprises four coaxial tubes generally represented at
220. Each coaxial tube is extruded and comprises an outer tube 223,
225, 227 and 229 with an open upper end 223', 225', 227' and 229',
an open lower end 223", 225", 227", and 229", and an inner tube
231, 233, 235, and 237 with a corresponding upper end 231', 233',
235', and 237', and a lower end 231", 233" 235" and 237".
[0070] FIG. 16 is a cross-sectional view of one of the coaxial
tubes. The cross-section of each coaxial tube is identical;
therefore, for purposes of simplicity, only one coaxial tube will
be described in detail. The outer tube 223 has an outer wall 239
and an inner wall 241, and the inner tube 231 has an outer wall 243
and an inner wall 245. Fins or separators 247 extend radially from
the outer wall 243 of the inner tube to the inner wall 241 of the
outer tube. Any number of fins may be used to separate the inner
and outer tubes. The inner and outer tubes as well as the fins may
be formed from aluminum, copper, or stainless steel or any other
suitable material.
[0071] Referring now to FIGS. 14, 15, and 17, when the coaxial
tubes 220 are extruded, inner tube and outer tube are the same
length. Subsequently, as shown with respect to one coaxial tube, a
portion of each end of the outer tube 223 and the fins 247 are
machined off such that lower end 231" and upper end 231' of the
inner tube 231 extend beyond the lower and upper ends 223" and 223'
of the outer tube 223. In addition, at the upper end of the outer
tube 223, a second portion of the outer tube is machined off
leaving an exposed portion 249 of the inner tube 231 and a ring 251
of outer tube 223. Ring 251 functions as a stopper to prevent the
coaxial tube from sliding up and down in the accumulator housing
and assists in securing the coaxial tube to the lower surface 255
of the top. The coaxial tubes may be attached to the top by
brazing, welding, soldering or any other suitable method.
[0072] Each coaxial tube is positioned in the accumulator housing
in the same manner. For example, inner tube 231 extends through the
top, into upper chamber, through the separator, through the lower
chamber, and exits bottom of the accumulator. In contrast, outer
tube 223, extends from beneath the lower surface 255 of the top
through the separator and terminates in the lower chamber directly
below the separator 187.
[0073] The lower end 231" of the inner tube 231 functions as the
high pressure inlet port, and the lower end 233" of the inner tube
233 functions as the high pressure outlet port for the accumulator.
Preferably, inner tubes 231, 233, 235 and 237 are serially
connected to from a continuous conduit for the flow of high
pressure, high temperature refrigerant through the heat exchanger.
To that end, as shown in FIG. 14, the upper end 231' of inner tube
231 is connected to the upper end 237' of inner tube 237 by a
jumper 257. The jumper 257 is generally a U-shaped cylinder having
a first end 259 and a second end 261 for receiving inner tubes 231'
and 237' respectively. The diameter of the jumper 257 is generally
slightly greater than the diameter of the inner tubes of 231' and
237' such that the tubes are inserted into the first and second
ends of the jumper and matingly engaged. The jumper may be formed
from aluminum, stainless steel, copper, or any other suitable
material. The jumper 257 is preferably formed from aluminum.
Welding, brazing, or soldering may be used to securely connect the
jumper to the inner tubes. The lower end 237" of inner tube 237 is
connected to the lower end 235" of inner tube 235 with a jumper 263
identical in all respects to the jumper 257. Upper end 235' of
inner tube 235 is connected to upper end 233' of inner tube 233
with a jumper 265.
[0074] While the inner tubes of the heat exchanger are preferably
serial connected, they may also be connected in a parallel
arrangement. Such an arrangement allows for two different high
temperature fluids to be cooled. For example, the upper end 231'
may be connected to the upper end 237' by a jumper such that the
lower ends 231" and 237" function as an inlet and outlet ports.
Similarly, the upper ends 233' and 235' may be connected by a
jumper such that the lower ends 233" and 235" function as inlet and
outlet ports.
[0075] In operation, the accumulator 180 is positioned in an air
conditioning or refrigeration system as shown in FIG. 1. Again,
familiarity with the general flow of refrigerant through such a
system is presumed. Arrows have been added to FIGS. 14 and 15 to
indicate the direction of the flow of refrigerant through the
accumulator and heat exchanger. High pressure, high temperature
liquid refrigerant exits a condenser and enters lower end 231" of
inner tube 231 and flows through all four serially connected inner
tubes and is discharged through lower end 233" of inner tube 233 to
the expansion device. At the same time, low pressure, temperature
refrigerant from the evaporator enters inlet port 205 and flows
into the upper chamber 197 of the housing. Liquid refrigerant flows
to the bottom of the upper chamber where it is stored. Gaseous
refrigerant rises and enters the upper ends 223', 225' 227' and
229' of the outer tubes. The gaseous refrigerant flows down the
outer tubes in a heat exchange relationship with the high pressure,
high temperature refrigerant flowing through the inner tubes, and
is discharged into the lower chamber 199. The gaseous refrigerant
then flows into the inlet end 219 of the vapor conduit 213 and
flows in an upward direction and exits the accumulator at the upper
end 221 of the vapor conduit and flows back to the compressor.
[0076] While the invention with its several embodiments has been
described in detail, it should be understood that various
modifications may be made to the present invention without
departing from the scope of the invention. The following claims,
including all equivalents define the scope of the invention.
* * * * *