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 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.
2. The desiccant cup as recited in claim 1 wherein said first end
comprises high temperature resistant plastic.
3. The desiccant cup as recited in claim 2 wherein said high temperature
plastic comprises a polypropylene/nylon blend.
4. The desiccant cup as recited in claim 1 wherein said first end
further includes a shrinkable plastic collar therearound.
5. 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.
6. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 5 wherein said first end comprises
high temperature resistant plastic.
7. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 6 wherein said high temperature resistant
plastic comprises a polypropylene/nylon blend.
8. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 5 further including an insulating o-ring
encircling said first end of said tube.
9. The desiccant cartridge used in combination with an R/D or accumulator
canister as recited in claim 8 wherein said o-ring comprises HNBR
rubber.
10. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 5 wherein said first end
of said elongated tube further includes a shrinkable plastic collar
therearound.
11. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 5 further comprising a
tubular insert connecting said first end of said tube and said outlet
port.
12. The desiccant cartridge as recited in claim 5 wherein said
outlet comprises a tubular head extension, said first end of said
elongated tube received within said head extension and a ferrule
disposed within said first end of said elongated tube to assist
in sealing said elongated tube and said outlet port.
13. 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 center tube to communicate
with said center tube.
14. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 13 wherein said tubular
insert comprises a high temperature resistant plastic.
15. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 14 wherein said high temperature
resistant plastic comprises a polypropylene/nylon blend.
16. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 13 wherein said tubular
insert comprises a heat insulating elastomer.
17. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 16 wherein said heat insulating
elastomer comprises HNBR rubber.
18. The desiccant cartridge used in combination with an R/D or
accumulator canister as recited in claim 13 wherein said first end
of said elongated tube further includes a shrinkable plastic collar
therearound.
19. A desiccant cartridge adapted for use in an R/D or accumulator
canister of the type having a port member in said canister, said
cartridge comprising a foraminous housing for reception of said
desiccant therein while allowing fluid flow therethrough and an
elongated tube member extending from said housing and adapted to
communicate with said port member.
20. A desiccant cartridge as recited in claim 19 wherein said elongated
tube member is integrally formed with said housing.
21. A desiccant cartridge as recited in claim 19 further comprising
a heat insulating o-ring interposed between said elongated tube
member and said port.
22. A desiccant cartridge as recited in claim 19 further comprising
a tubular insert member connecting said elongated tube member to
said port.
23. A desiccant cartridge as recited in claim 19 wherein said elongated
tube member comprises a terminal portion thereof adapted for contiguous
mating with said port.
Description CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The benefit of prior U.S. Provisional Application filed
Oct. 29 2001 entitled DESICCANT CARTRIDGE WITH ELONGATED CENTER
TUBE (SNH 057 P2 USP1) is hereby claimed.
FIELD OF THE INVENTION
[0002] 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
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] Other objects and advantages of the invention will be apparent
from the following description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a front perspective view of one embodiment of
the desiccant cartridge of the present invention;
[0027] FIG. 2 is a cross-sectional view of the desiccant cartridge
of FIG. 1;
[0028] 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;
[0029] FIG. 4 is a front perspective view of an R/D or accumulator
canister of the present invention;
[0030] 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;
[0031] FIG. 6 is a cross-sectional view of the desiccant cartridge
of FIG. 1 installed in the canister of FIG. 4;
[0032] 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;
[0033] 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
[0034] FIG. 9 is a cross-sectional view of another embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] 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.
[0036] 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.
[0037] 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.
[0038] In another embodiment, as shown in FIG. 3 the first end
32 is comprised of a high temperature plastic 54 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 54.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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).
[0045] As best shown in FIGS. 4 and 6 an RID 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.
[0046] 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.
[0047] 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.
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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.
[0053] 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. |