Abstrict This invention relates generally to desiccant cartridges for use
in R/Ds or accumulators canisters of automotive air conditioning
systems. More specifically, this invention relates to a desiccant
cartridge including a cup having inner and outer walls coaxially
disposed wherein the inner wall defines an elongated center tube
having opposing first and second ends. The first end of the center
tube communicating with the outlet port in an R/D or accumulator
canister to eliminate the fluid flow tube used therein.
Claims What is claimed is:
1. A desiccant cartridge used in combination with an R/D or accumulator
canister comprising: a desiccant cartridge comprising a cup having
spaced inner and outer walls said outer wall comprising an upper
and lower edge, said cup further comprising a transverse portion
having a top and bottom surface, said transverse portion cooperating
with said inner and outer wall to define a chamber having an opening
such that said bottom surface faces away from said chamber, said
inner wall further defining an elongated tube having opposing first
and second ends, said second end extending away from said bottom
surface of said transverse portion, a plurality of desiccant particles
contained within said chamber, a cap comprising a planar portion
having an inner circumference defining an aperture for slidably
receiving said tube, said cap being securely received within said
opening to contain said particles within said chamber; an R/D or
accumulator canister including an outer wall and opposing top and
bottom walls connected to said outer wall to define a chamber, said
top wall having a port therein; a tubular insert having first and
second ends; and wherein said cartridge is securely retained within
said chamber of said R/D or accumulator canister, said first end
of said tube being aligned with said outlet port, and said first
end of said tubular insert fitting inside and sealingly engaging
said first end of said tube and said second end of said insert sealingly
engaging said outlet port thereby allowing said elongated tube to
communicate with said port, said tubular insert being composed of
a high temperature resistant polymer.
2. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 1 wherein said high temperature resistant
polymer comprises a polypropylene/nylon blend.
3. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 1 wherein said high temperature resistant
polymer comprises a heat insulating elastomer.
4. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 3 wherein said heat insulating elastomer
comprises HNBR rubber.
5. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 1 wherein said tubular insert comprises
a shrinkable plastic collar connecting said port and said first
end of said elongated tube.
6. A desiccant cartridge used in combination with a R/D or accumulator
canister comprising: a desiccant cartridge comprising a cup having
spaced inner and outer walls, said outer wall comprising an upper
and lower edge, said cup further comprising a transverse portion
having a top and bottom surface, said transverse portion cooperating
with said inner and outer walls to define a chamber having an opening
such that said bottom surface faces away from said chamber, said
inner wall further defining an elongated tube having opposing first
and second ends, said first end extending above said transverse
portion, a plurality of desiccant particles contained within said
chamber, a cap comprising a planar portion having an inner circumference
defining an aperture for slidably receiving said tube, said cap
being securely received within said opening to contain said particles
within said chamber; a R/D or accumulator canister including an
outer wall and opposing top and bottom walls connected to said outer
wall to define a chamber, said top wall having a port therein; and
wherein said cartridge is securely retained within said chamber
of said R/D or accumulator canister such as that said first end
of said tube is in communication with said outlet port and said
second end is in communication with said bottom wall of said receiver
dryer; said first end of said elongated tube being received within
said port, and a ferrule force fit within said first end of said
elongated tube to urge said first end into sealing contact with
said port.
7. A desiccant cup comprising: spaced inner and outer walls, said
outer wall comprising an upper and lower edge, said inner wall further
defining an elongated tube having opposing first and second ends;
and a transverse portion having a top and bottom surface, said transverse
portion further cooperating with said inner and outer walls to define
a chamber having an opening such that said bottom surface faces
away from said chamber, said first end of said elongated tube extending
above said upper edge of said outer wall and said second end of
said elongated center tube extending away from said bottom surface
of said transverse portion wherein said first end comprises a high
temperature resistant plastic, said high temperature resistant plastic
being a polypropylene/nylon blend.
8. A desiccant cartridge used in combination with an R/D or accumulator
canister comprising: a desiccant cartridge comprising a cup having
spaced inner and outer walls, said outer wall comprising an upper
and lower edge, said cup further comprising a transverse portion
having a top and bottom surface, said transverse portion cooperating
with said inner and outer walls to define a chamber having an opening
such that said bottom surface faces away from said chamber, said
inner wall further defining an elongated tube having opposing first
and second ends, said first end extending above said upper edge
of said outer wall and said second end extending away from said
bottom surface of said transverse portion, a plurality of desiccant
particles contained within said chamber, a cap comprising a planar
portion having an inner circumference defining an aperture for slidably
receiving said tube, said cap being securely received within said
opening to contain said particles within said chamber; an R/D or
accumulator canister including an outer wall and opposing top and
bottom walls connected to said outer wall to define a chamber, said
top wall having an outlet port therein; and wherein said cartridge
is securely retained within said chamber of said R/D or accumulator
canister such that said first end of said tube is in communication
with said outlet port and said second end is in communication with
said bottom wall of said receiver dryer, said first end comprising
a high temperature resistant plastic, said high temperature resistant
plastic being a polypropylene/nylon blend.
9. A desiccant cartridge used in combination with an R/D or accumulator
canister comprising: a desiccant cartridge comprising a cup having
spaced inner and outer walls said outer wall comprising an upper
and lower edge, said cup further comprising a transverse portion
having a top and bottom surface, said transverse portion cooperating
with said inner and outer wall to define a chamber having an opening
such that said bottom surface faces away from said chamber, said
inner wall further defining an elongated tube having opposing first
and second ends, said second end extending away from said bottom
surface of said transverse portion, a plurality of desiccant particles
contained within said chamber, a cap comprising a planar portion
having an inner circumference defining an aperture for slidably
receiving said tube, said cap being securely received within said
opening to contain said particles within said chamber; an R/D or
accumulator canister including an outer wall and opposing top and
bottom walls connected to said outer wall to define a chamber, said
top wall having an outlet port therein; a tubular insert having
first and second ends; and wherein said cartridge is securely retained
within said chamber of said R/D or accumulator canister, said first
end of said tube being aligned with said outlet port, and said first
end of said tubular insert fitting inside and sealingly engaging
said first end of said tube and said second end of said insert sealingly
engaging said outlet port thereby allowing said elongated tube to
communicate with said outlet port, said tubular insert comprising
a high temperature resistant plastic, said high temperature resistant
plastic being a polypropylene/nylon blend.
10. A desiccant cup comprising: spaced inner and outer walls, said
outer wall comprising an upper and lower edge, said inner wall further
defining an elongated tube having opposing first and second ends,
said first end comprising a high temperature resistant plastic;
an insulating o-ring encircling said first end of said tube; and
a transverse portion having a top and bottom surface, said transverse
portion further cooperating with said inner and outer walls to define
a chamber having an opening such that said bottom surface faces
away from said chamber, said first end of said elongated tube extending
above said upper edge of said outer wall and said second end of
said elongated center tube extending away from said bottom surface
of said transverse portion, said high temperature plastic comprising
a polypropylene/nylon blend.
11. A desiccant cartridge used in combination with a R/D or accumulator
canister comprising: a desiccant cartridge comprising a cup having
spaced inner and outer walls, said outer wall comprising an upper
and lower edge, said cup further comprising a transverse portion
having a top and bottom surface, said transverse portion cooperating
with said inner and outer walls to define a chamber having an opening
such that said bottom surface faces away from said chamber, said
inner wall further defining an elongated tube having opposing first
and second ends, said first end comprising a high temperature resistant
plastic and extending above said transverse portion, an insulating
o-ring encircling said first end of said tube, a plurality of desiccant
particles contained within said chamber, a cap comprising a planar
portion having an inner circumference defining an aperture for slidably
receiving said tube, said cap being securely received within said
opening to contain said particles within said chamber; a R/D or
accumulator canister including an outer wall and opposing top and
bottom walls connected to said outer wall to define a chamber, said
top wall having an outlet port therein; and wherein said cartridge
is securely retained within said chamber of said R/D or accumulator
canister such that said first end of said tube is in communication
with said outlet port and said second end is in communication with
said bottom wall of said receiver dryer, said high temperature resistant
plastic comprising a polypropylene/nylon blend.
12. The combination as recited in claim 6 wherein said ferrule
comprises a high temperature resistant polymer material.
13. The combination as recited in claim 12 wherein said high temperature
resistant polymer material comprises a polypropylene/nylon blend.
14. The combination as recited in claim 12 wherein said high temperature
resistant polymer material comprises a high temperature resistant
elastomer.
15. A desiccant cartridge used in combination with a R/D or accumulator
canister comprising: a desiccant cartridge comprising a cup having
spaced inner and outer walls, said outer wall comprising an upper
and lower edge, said cup further comprising a transverse portion
having a top and bottom surface, said transverse portion cooperating
with said inner and outer walls to define a chamber having an opening
such that said bottom surface faces away from said chamber, said
inner wall further defining an elongated tube having opposing first
and second ends, said first end extending above said transverse
portion, a plurality of desiccant particles contained within said
chamber, a cap comprising a planar portion having an inner circumference
defining an aperture for slidably receiving said tube, said cap
being securely received within said opening to contain said particles
within said chamber; a R/D or accumulator canister including an
outer wall and opposing top and bottom walls connected to said outer
wall to define a chamber, said top wall having a port therein; and
wherein said cartridge is securely retained within said chamber
of said R/D or accumulator canister such that said first end of
said tube is in communication with said port and said second end
is in communication with said bottom wall of said receiver dryer,
and a heat shrinkable collar surrounding said first end of said
tube and said port.
Description FIELD OF THE INVENTION
This invention relates generally to desiccant cartridges for use
in receiver/dryers or accumulator canisters of automotive air conditioning
systems. More specifically, it relates to a desiccant cartridge
including a cup having an elongated center tube for replacing the
fluid flow tube in a receiver/dryer or accumulator canister.
BACKGROUND OF THE INVENTION
Desiccant cartridges containing desiccant particles are common
in automotive air conditioning systems for dehydrating refrigerants.
These desiccant cartridges are adapted to fit within receiver/dryer
and accumulator canisters or assemblies.
Receiver/Dryer (R/D) and accumulator assemblies are used in automotive
air conditioning assemblies to separate liquid refrigerant from
gaseous refrigerant and to pass only the liquid downstream in the
system. In many of these assemblies, a fluid flow tube is integrally
formed with the top wall of the R/D or accumulator assembly and
is commonly composed of metal such as stainless steel or aluminum.
Desiccant containing cartridges such as those shown in U.S. Pat.
Nos. 5814136; 5716432; 5685087; 5569316; 5540348; 5529203;
and 5522204 are disposed in the R/D and accumulator assemblies
and function to dry the liquid refrigerant as it passes from the
assembly inlet through the fluid flow tube to an outlet port contained
in the structure. Typically, these cartridges contain a centrally
disposed sleeve member that is adapted for snug reception over the
fluid flow tube of the R/D or accumulator assembly so as to position
the cartridge inside the assembly housing.
Some of the drawbacks to these R/D or accumulator metal fluid flow
tubes are that they necessitate extra material, manufacturing, handling
and assembly costs. Also, metal tubes can introduce contaminates
into the air conditioning system in the form of metal chips and
debris. As such, elimination of the metal tube could realize a significant
cost savings and eliminate the risk of contamination.
Accordingly, there is a need in the art for the provision of a
more economical structure which uses, as the fluid flow tube, a
material that is less expensive than metal. An even more specific
need is presented for the provision of a fluid flow tube that is
integral with the desiccant containing cartridge.
Notably, the desiccant cartridge of the present invention is designed
to eliminate the costly metal center tube by replacing it with a
desiccant cartridge having a cup with an inner wall that defines
an elongated center tube having first and second ends wherein the
first end of the center tube communicates with the outlet port in
the top wall of the R/D or accumulator assembly. The first end is
formed from a plastic material, preferably a high temperature resistant
plastic, to withstand the heat when the top wall of the R/D or accumulator
assembly is welded to the canister-like housing. Also, it can be
advantageous to use plastics, such as a plastic collar, having certain
heat shrinkage properties so that the collar shrinks around the
first end of the center tube and outlet port to form a better seal
therebetween after the top wall of the canister is welded thereto.
In another aspect of the invention, the first end may be shaped
to receive a high temperature o-ring, tubular insert, or ferrule,
may be positioned within the first end of the center tube and outlet
port to fill and seal the outlet port from the top wall of the R/D
or accumulator and the center tube thereby further protecting and
insulating the first end from heat during welding of the top wall
of the R/D or accumulator onto the canister.
Accordingly, the center tube design of the desiccant cartridge
provides a simple way for replacing a metal fluid flow tube while
at the same time reducing the material, manufacturing, handling
and assembly costs associated therewith.
Additionally, the plastic center tube of the desiccant cartridge
further eliminates the metal chips and debris associated with metal
tubes which can harm air conditioning systems.
SUMMARY OF THE INVENTION
The present invention provides a desiccant cartridge of the type
including a cup having spaced inner and outer walls coaxially disposed
wherein the inner wall defines an elongated center tube having first
and second ends, and the outer wall has an upper and lower edge.
The cup further includes a transverse portion having a top and bottom
surface such that the transverse portion is connected to the outer
and inner wall to define a chamber having an opening with the bottom
surface of the transverse portion facing away from the chamber.
A plurality of desiccant particles is contained within the chamber
for dehydrating air and refrigerants, and a cap having a planar
portion with an inner circumference defining an aperture for slidably
receiving the tube is securely received within the opening of the
chamber to keep the desiccant particles contained therein.
In one embodiment, the cup has an elongated center tube with opposing
first and second ends wherein the first end extends above the upper
edge of the outer wall and the second end extends away from the
bottom surface of the transverse portion. The cup is a one-piece
plastic molding, preferably formed from polypropylene, by conventional
molding techniques.
In another embodiment, the first end is formed from a high temperature
resistant plastic, such as a polypropylene/nylon blend. In this
embodiment, the first end is molded separately from the cup then
press fit to the inner wall opposite the second end to form a center
tube having a first end comprising a high temperature resistant
plastic.
Accordingly, the desiccant cartridge of the present invention is
designed to be used in combination with an R/D or accumulator canister
including an outer wall axially disposed. The canister further has
a bottom wall cooperating with the outer wall to define a chamber
having an opening. The canister further is provided with a top wall
having an outlet port therein, preferably centrally located. During
assembly the top wall is secured, preferably by welding, to the
canister opposite the bottom wall to seal the chamber.
Prior to placing and welding the top wall onto the canister to
complete assembly of the R/D or accumulator, an assembled desiccant
cartridge is placed within the chamber so that the second end of
the tube communicates with a mounting flange that is spaced above
the bottom wall of the receiver dryer to support the cartridge.
When the top wall is placed onto the canister, the center tube aligns
with the outlet port such that the first end of the tube is in communication
therewith.
In either embodiment above, the first end may be shaped to receive
a temperature resistant o-ring to further protect and insulate the
first end from heat during welding of the top wall onto the canister.
Further, with respect to the center tube, and more specifically,
the first end of the tube, it can be advantageous to use plastics,
such as a plastic collar, around the first end of the tube which
have heat shrinkage properties so that after heating of the tube
during welding, shrinkage occurs during cooling so as to form a
better seal between the center tube and the outlet port.
In yet another embodiment, the first end of the tube cooperates
with a tubular insert to be able to communicate with the outlet
port. In this embodiment, after the desiccant cartridge is placed
into the R/D or accumulator canister and the top wall placed and
secured thereon, the ferrule is inserted through the outlet port
so that the insert sealingly engages with the first end of the tube
and sealingly engages with the outlet port to fill an air gap therebetween
allowing the center tube to communicate with the outlet port.
Accordingly, the elongated center tube configuration of the desiccant
cartridge effectively eliminates the need for fluid flow tubes in
R/Ds and accumulators. Instead, this fluid flow tube may be formed
as a part of the desiccant cartridge itself.
Therefore, it may be appreciated that an object of the present
invention is to provide a desiccant cartridge designed to eliminate
the metal center tube used in R/D and accumulators while at the
same time reducing the material, manufacturing, handling and assembly
costs associated therewith.
It is a further object of present invention to provide a desiccant
cartridge with an elongated center tube formed from plastic to eliminate
the chips and metal debris associated with metal tubes which can
harm air conditioning systems.
It is another object of the invention to provide a center tube
having a first end comprising a high temperature plastic to withstand
the heat from welding the top wall of the canister thereon.
Other objects and advantages of the invention will be apparent
from the following description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective view of one embodiment of the desiccant
cartridge of the present invention;
FIG. 2 is a cross-sectional view of the desiccant cartridge of
FIG. 1;
FIG. 3 is a cross-sectional view of another embodiment of the desiccant
cartridge of the present invention taken along the same plane shown
in FIG. 2;
FIG. 4 is a front perspective view of an R/D or accumulator canister
of the present invention;
FIG. 5 is a front perspective exploded view assembly of the desiccant
cartridge shown in FIG. 1 and the canister in FIG. 4 without the
top wall;
FIG. 6 is a cross-sectional view of the desiccant cartridge of
FIG. 1 installed in the canister of FIG. 4;
FIG. 7 is a cross-sectional view of the desiccant cartridge represented
by FIG. 3 installed in the canister of FIG. 4 and further illustrating
a high temperature o-ring;
FIG. 8 is a cross-sectional view of another embodiment of the desiccant
cartridge of the present invention installed in the canister of
FIG. 4 and illustrating a tubular insert; and
FIG. 9 is a cross-sectional view of another embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1-9 show the present invention which concerns a desiccant
cartridge 10 including a cup 12 having an elongated center tube
14 for replacing the fluid flow tube (not shown) in an R/D or accumulator
canister 16.
As best shown in FIGS. 1 and 2 the desiccant cartridge 10 includes
a generally cylindrical cup 12 having spaced inner and outer walls
18 and 20 coaxially disposed and a cap 22. The inner wall 18 of
the cup 12 defines an elongated center tube 14 having first and
second ends 32 and 34 and the outer wall 20 comprises an upper and
lower edge 36 and 38 and has an inner surface 40. The desiccant
cartridge 10 further has a transverse portion 42 with a top and
bottom surface 44 and 46 and which cooperates with the inner and
outer wall 18 20 to define a chamber 48 having an opening 50 such
that the bottom surface 46 faces away from the chamber 48. Accordingly,
the cap 22 conforms to the shape of the cup 12 and has a planar
portion 24 with a centrally located aperture 30 (FIG. 5) for receiving
the inner wall 18 when the cap 22 is received in the chamber 48.
FIGS. 1 and 2 further show that the cup 12 is a one-piece plastic
molding, preferably formed from polypropylene, by conventional molding
techniques wherein the first end 32 of the elongated center tube
14 extends above the upper edge 36 of the outer wall 20 and the
second end 34 of the elongated center tube 14 extends away from
the bottom surface 46 of the transverse portion 42.
In another embodiment, as shown in FIG. 3 the first end 32 is
comprised of a high temperature plastic 154 preferably formed from
a polypropylene/nylon blend to offer greater heat protection than
the polypropylene material. In this embodiment, the first end 32
is molded separately from the cup 12 using conventional molding
techniques so that the first end 32 will mate with the inner wall
18. After the first end 32 is molded, it is press fit onto the inner
wall 18 opposite the second end 34 to form a continuous elongated
center tube 14 having a first end 32 made of a high temperature
plastic.
FIGS. 2 and 3 further shows a plurality of desiccant particles
52 for dehydrating air and refrigerants (not shown) situated within
the chamber 48 along with an optional dye wafer 54 which is helpful
for detecting leaks in an a/c system (not shown). The cap 22 which
slidably receives the tube 14 through its aperture 30 is securely
received within the opening 50 of the chamber 48 to keep the desiccant
particles 52 and dye wafer 54 contained therein. Notably, the inner
surface 40 of the outer wall 20 of the cup 12 may include a plurality
of inner surface protrusions including, but not limited to, ribs,
nibs, beads, bumps or other equivalent protrusions (not shown) projecting
radially inwardly from the outer wall 20 which engage and retain
the cap 22 in one of a number of axially spaced positions.
Further, in FIGS. 1 and 5 the planar portion 24 of the cap 22
is perforated with a number of generally kidney shaped ports 56
so that the planar portion 24 is permeable to the refrigerant fluid
(not shown) to be dried. Although not shown, like the cap 22 the
transverse portion 42 of the cup 12 similarly has ports therein.
The precise arrangement and shapes of the ports 56 is not critical
to the operation of the desiccant cartridge 10 as long as the desiccant
52 remains contained within the cartridge and the refrigerant fluid
(not shown) is allowed to enter the cartridge 10 interact evenly
with the desiccant 52 exit from the cartridge 10 and then flow
through the elongated center tube 14.
FIG. 1 also shows that the outer wall 20 can include at least one
outwardly flared continuous lip portion 58. The flared lip portion
58 is adapted to resiliently fit, by a friction or interference
fit, within an R/D or accumulator canister 16 (FIG. 4) of an air
conditioning or refrigeration system (not shown). The lip portion
58 serves as a continuous annular seal to prevent air or fluid escape
that may otherwise occur along the interface between the circumference
of the cup 12 and the canister 16 (FIG. 4). Although the lip 58
is shown spaced below the top 60 of the cup 12 it can be located
anywhere along the axial length dimension of the cup 12.
As shown in FIGS. 2 and 3 a permeable lining material 62 and 64
such as a two-ply fiberglass, can be placed inside the chamber 48
near the transverse portion 42 and the cap 22 to trap the desiccant
52 in the cartridge 10. The plies 62 64 must be permeable to the
air or fluid (not shown) to be dried but impermeable to the particulate
desiccant 52. Although the use of a two-ply fiberglass is preferred,
the artisan can appreciate that other materials such as gauze or
felt may be substituted.
Accordingly, when the desiccant cartridge 10 is charged with the
desiccant 52 the permeable lining material 62 can be inserted by
sliding it down the inner wall 18 until positioned adjacent the
transverse portion 42. The dye wafer 54 is first placed into the
chamber 48 and next the required amount of desiccant 52 is poured
therein. Once the desiccant 52 is charged, the permeable lining
material 64 can be slid down the inner wall 18 against the desiccant
52 and the cap 22 secured to the cup 12.
Once the desiccant cartridge 10 is assembled, it can then be inserted
into the chamber 76 (FIG. 5) of an R/D or accumulator canister 16
(FIG. 4). The cup 12 (FIG. 4) may be vibrator or bowl fed to a robotic
arm (not shown) for automatic installation into the canister 16
(FIG. 4).
As best shown in FIGS. 4 and 6 an R/D or accumulator canister
16 typically includes an outer wall 70 axially disposed and a bottom
wall 72 cooperating with the outer wall 70 to define a chamber 76
having an opening 73. The bottom wall 74 is preferably v-shaped.
The canister 16 further is provided with a top wall 72 having an
outlet port 80 preferably centrally located, and one of the walls
70 72 74 shown here as the top wall 72 further comprises an
inlet port 82. During assembly the top wall 72 is secured, preferably
by welding, to the canister 16 opposite the bottom wall 74 to seal
the chamber 76. In this embodiment, note that the first end of the
center tube is contiguous with the extension of port 80.
Prior to placing the top wall 72 onto the canister 16 to complete
assembly of the R/D or accumulator 68 as best shown in FIGS. 6
and 7 an assembled desiccant cartridge 10 is placed within the
chamber 76 of the canister 16 so that the second end 34 of the tube
14 is spaced above the bottom wall 74 by the use of a pedestal-like
mounting structure.
Additionally, as shown in FIG. 7 an insulating o-ring 84 may be
placed around the first end 32 of the center tube 14 to offer further
protection from heat encountered from welding the top wall 72 of
the canister 16 thereon. The high temperature o-ring 84 preferably
is made from a high temperature HNBR rubber material available from
Parker.
As can be seen in FIGS. 6 and 7 when the top wall 72 is placed
and welded onto the canister 16 the center tube 14 aligns with
the outlet port 80 such that the first end 32 of the tube 14 is
in communication therewith to allow for removal of air or fluid
(not shown) flowing into the canister 16 from the inlet port 82
during operation.
Further, with respect to the center tube 14 as shown in FIG. 9
and more specifically, the first end 32 of the tube, it can be advantageous
to use a plastic collar 103 having certain heat shrinkage properties
so that after welding of the R/D or accumulator lid to the housing,
the tube cools and shrinks to form a better seal with the outlet
port 80. In the embodiment shown in FIG. 9 the heat shrinkable
collar fits around the outer diameter of the extension 80 and the
upper end 32 of the center tube covering the air space between the
extension and the tube. Upon heating or in the welding process for
the can assembly, the collar will shrink back to its elastic limit.
Accordingly, the artisan will appreciate that the center tube 14
may comprise varying lengths such that the first end 32 does not
communicate with the outlet port 80.
In the embodiment shown in FIG. 8 a resilient tubular insert 88
or ferrule, larger in diameter than the center tube 14 is inserted
through the outlet port 80 so that the ferrule fits snugly into
the inner diameter of the first end 32 of the tube 14 forcing the
tube radially outwardly to form a seal with the head portion 92
of the outlet port from the R/D or accumulator. The tubular insert
88 may be formed from a high temperature plastic, such as a polypropylene/nylon
blend or high temperature elastomer.
As best shown in FIG. 8 during operation of the a/c system (not
shown), air or refrigerant (not shown) enters the canister 16 through
the inlet port 82 as indicated by arrow 94. The refrigerant fluid
flows through the ports 56 in the cap 22 and into the chamber 48
containing the desiccant 52 as indicated by arrow 95. Moisture is
removed from the refrigerant fluid by the desiccant 52 while solid
particles (not shown) are filtered by the plies 62 64. The treated
refrigerant then exits the cup 12 through the ports (not shown)
in the transverse portion 42 enters the second end 34 of the center
tube 14 as indicated by arrow 96 and finally exits the canister
16 via the outlet port 80 as indicated by arrow 97 in FIG. 8. As
may be appreciated, fluid flow is not permitted around the cup 12
due to the seal formed between the flared lip portion 58 and the
canister 16.
Accordingly, the elongated center tube of the desiccant cartridge
effectively eliminates the need for fluid flow tubes in R/Ds and
accumulators. As such, the center tube design of the desiccant cartridge
provides a simple way for replacing a metal fluid flow tube while
at the same time reducing the material, manufacturing, handling
and assembly costs associated therewith. Also, the plastic center
tube of the desiccant cartridge further eliminates the metal chips
and debris associated with metal tubes which can harm air conditioning
systems.
While the forms of apparatus herein described constitute preferred
embodiments of the invention, it is to be understood that the invention
is not limited to these precise forms of apparatus, and that changes
may be made therein without departing from the scope of the invention. |