Abstrict A container for particulate desiccant comprises a cup and a cap.
The cup includes spaced inner and outer wall portions connected
by a transverse web portion to define a chamber having an opening.
The cap is designed for receipt in the chamber to cover the opening.
In addition, the cap has a hole for receiving the inner wall portion
of the cup. The outer wall portion includes a number of nib segments
which are arranged into axially spaced nib groupings. The nib segments
within each of the nib groupings are circumferentially spaced-apart.
The cap includes an edge portion which permits the cap to be retained
between axially adjacent nib groupings thus retaining the cap within
the chamber in one of a number of axially spaced positions.
Claims What is claimed is:
1. A container for a particulate desiccant, said container comprising:
an cup member extending along an axis and including spaced inner
and outer wall portions connected by a transverse web portion to
define a chamber having an opening;
a cap for receipt in said chamber, said cap having a hole for receiving
said inner wall portion when said cap is received in said chamber;
and
a plurality of nib segments projecting radially inwardly from said
outer wall portion which engage and retain said cap in one of a
plurality of axially spaced positions to prevent shifting of the
particulate desiccant within said chamber.
2. The container claimed in claim 1 wherein said nib segments
are arranged into a plurality of axially spaced nib groupings.
3. The container claimed in claim 2 wherein said nib segments
are arranged into four axially spaced nib groupings.
4. The container claimed in claim 2 wherein said nib segments
within each of said nib groupings are oriented in a common plane
which extends transverse to said axis.
5. The container claimed in claim 2 wherein said nib segments
within each of said nib groupings are circumferentially spaced-apart.
6. The container claimed in claim 2 wherein said nib segments
within each of said nib groupings are circumferentially spaced-apart
by about 45.degree..
7. The container claimed in claim 1 wherein said transverse web
portion and said cap include perforations therein.
8. The container claimed in claim 1 wherein said inner and outer
walls are concentric cylinders.
9. The container claimed in claim 1 wherein said outer wall portion
includes a flared lip extending outwardly from said outer wall.
10. The container claimed in claim 1 wherein said inner wall portion
defines a sleeve open at either end on different sides of said container.
11. The container claimed in claim 1 including first and second
plies of permeable lining material for placement in said chamber
to trap the particulate desiccant in the container.
12. A container claimed in claim 1 wherein said cup is a one-piece
casting.
Description BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to desiccant containers for use in air or
fluid dryers of automotive air conditioning systems, and more particularly,
it relates to a desiccant container having locking nibs which permit
a cap to be retained in one of a number of axially spaced positions
to prevent particulate desiccant from shifting within the container.
2. Description of Related Art
Desiccants are commonly used in automotive air conditioning systems
for dehydrating air and refrigerants. Particulate desiccants are
common in such systems because the high surface area-to-volume ratios
of the particles facilitates the interaction of the particles with
surrounding air or fluid. Since the particles of desiccant must
be held in the air or fluid stream and prevented from contaminating
other parts of the system, the particles must be held in a container
which is permeable to the air or fluid but impermeable to the particles.
One form of dryer used in automotive air conditioning systems includes
an elongated receiver or accumulator canister having inlet and outlet
ports communicating with the interior of the canister. A desiccant
container is positioned in the interior of the canister and allows
for air and/or fluid through the desiccant material.
One form of package-type desiccant container for use in an accumulator
or receiver dryer is constructed from synthetic felted wool or polyester
which is filled with desiccant and then sealed by stitching or fusing.
One drawback to this form of package is that the felted bag may
not conform to the shape of the canister, so that air or fluid may
bypass the desiccant. Another drawback is that the bag may be non-uniform
in shape, thereby making automatic assembly of the dryer difficult.
If felted polyester is used as a less expensive substitute for
felted wool, the seams of the bag may be formed by ultrasonic welding.
Unfortunately, the reliability of such ultrasonic welds is questionable
and the bag may open up, allowing adsorbent material to escape from
the bag and potentially contaminate the system. In addition, the
felted polyester bag is vulnerable to burn-through when the dryer
is welded shut.
In another proposed form of an accumulator or receiver dryer, particulate
desiccant is trapped between a pair of grids or plates which are
welded or press fit inside the canister. According to one embodiment,
the desiccant is charged by pouring the desiccant particles into
the canister once a first of the grids or plates is positioned.
A pipe extends through holes in the grids or plates to exhaust dried
air to an outlet port.
A dryer of this form is likely to be difficult to assemble because
the grids or plates must be slid into position and, in some cases,
welded inside the canister. Further, since the desiccant particles
are manually poured into the canister, the desiccant must be pre-measured
due to the difficulty of controlling the amount of desiccant poured
into the canister based on visual observation alone. The pouring
of the desiccant creates a risk of accidental contamination outside
the accumulator since desiccant particles may fall into the pipe
communicating with the outlet port. Nevertheless, the amount of
desiccant poured into the canister may vary from canister to canister
for at least the reasons mentioned above.
Copending patent application Ser. No. 08/235 283 assigned to
the same assignee of the present invention, discloses a two-piece
desiccant container which can be inserted within an accumulator
or receiver dryer. The desiccant container includes a cup for holding
particulate desiccant and a cap which is locked to the cup by an
integral detent on an inner wall portion of the cup.
The particulate desiccant is either poured directly into the cup,
or a felted bag containing particulate desiccant is inserted into
the cup before the desiccant container is inserted within the receiver
dryer. In both cases, the amount of desiccant placed within the
cup is critical to whether or not the particulate desiccant can
shift within the cup once the cap is locked in place. That is, the
cup and cap cooperate to define a chamber having a predetermined
fixed volume. If there is not enough particulate desiccant to fill
the predetermined volume, or if the desiccant should settle over
time, then the particulate desiccant within the container will undesirably
shift within chamber.
SUMMARY OF THE INVENTION
These drawbacks and others are overcome by means of the present
invention embodied in a container for a particulate desiccant.
The desiccant container includes a cup member extending along an
axis and having spaced inner and outer wall portions connected by
a transverse web portion to define a chamber having an opening,
and a cap for receipt in the chamber. The cap has a hole for receiving
the inner wall portion when the cap is received in the chamber.
The desiccant container also includes a plurality of nib segments
projecting radially inwardly from the outer wall portion which engage
and retain the cap in one of a number of axially spaced positions
to prevent shifting of the particulate desiccant within the chamber.
Shifting of the charged desiccant within the chamber is prevented
by urging the cap over the nib segments until the cap abuts the
desiccant material within the chamber. The cap is lockingly retained
into abutment with the desiccant material by engaging the nib segments
positioned axially adjacent the cap.
Both the transverse web portion and the cap are perforated to allow
air or fluid to reach the desiccant housed thereon. The container
includes first and second plies of permeable lining material which
trap the particulate desiccant in the container.
Therefore, it is one object of the invention to provide a desiccant
package which is simple to assemble, and prevents the shifting of
desiccant with the chamber thereof. This and other objects, features
and advantages of the present invention will be described in further
detail in connection with preferred embodiments of the invention
shown in the accompanying drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a front elevational view of a desiccant container of
the present invention;
FIG. 2A is a top plan view of the desiccant container of FIG. 1
without the cap installed;
FIG. 2B is a top plan view of the desiccant container of FIG. 1
with the cap installed;
FIG. 3A is a cross-sectional view of the desiccant container taken
along the line 3A--3A in FIG. 2B;
FIG. 3B is an enlarged sectional view of cap being retained between
adjacent nib groupings of the cup.
FIG. 4 is a bottom plan view of the desiccant container of FIG.
1; and
FIG. 5 is a cross-sectional view of the desiccant container of
FIG. 1 installed in a canister of an accumulator or receiver dryer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1-4 illustrate a desiccant container 10 for holding desiccant
particles or beads 12 (FIG. 3A) which comprises a generally cylindrically
cross-sectioned cup 14 and a cap 16.
As best seen in FIG. 3A, the cup 14 is a one-piece plastic molding
which includes a cylindrical inner wall portion 18 extending along
a central axis 20 a cylindrical outer wall portion 22 concentric
with the inner wall portion 18 and a bottom defined by a transverse
wall or web portion 24 which joins the inner wall portion 18 to
the outer wall portion 22. The inner and outer wall portions 18
22 and the transverse web portion 24 cooperate to define a chamber
26 having an opening 28 (FIG. 1) for receiving the desiccant 12.
The cylindrical outer wall portion 22 includes a plurality of axially
and circumferentially spaced-apart beads or nib segments 30 (FIG.
2A) projecting radially inwardly from an inner surface 32 of the
outer wall portion 22. The plurality of nib segments 30 are arranged
into four axially spaced-apart groupings 34 (FIG. 3B) proximate
a cap side of the container 10. The nib segments 30 within each
grouping 34 are oriented in a common plane which extends transverse
to the central axis 20. Further, the nib segments 30 within each
grouping 34 are circumferentially spaced-apart by approximately
45.degree.. As discussed further below, the nib segments 30 permit
the cap 16 to be retained within the chamber 26 in the tightest
possible location in order to reduce or prevent movement or shifting
of the particulate desiccant 12 within the chamber 26.
The outer wall portion 22 also includes an outwardly flared lip
portion 38. The flared lip portion 38 is adapted to resiliently
fit within a dryer canister 40 (FIG. 5) of an air conditioning or
refrigeration system not shown. Thus, the desiccant container 10
is retained within the dryer canister 40 by means of a friction
or interference fit provided by the flared lip portion 38. The lip
portion 38 also 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 14 and the dryer canister 40.
The transverse web portion 24 includes a plurality of circumferentially
spaced-apart arcuate spacer elements or legs 42 and a central inner
wall extension portion 44. In the preferred embodiment, there are
three legs spaced approximately 120.degree. apart which extend axially
from a peripheral edge of the transverse web portion 24 radially
adjacent the outer wall portion 22 (FIG. 4). The legs 42 maintain
the desiccant container 10 at a predetermined distance away from
a closed end portion 46 of the dryer canister 40 as discussed further
below.
The inner wall extension portion 44 is coaxially joined to and
communicates with the inner wall portion 18 at a web side of the
container 10. The extension portion 44 has a tapered free end 48
which tapers toward the closed end portion 46 of the canister 40
to facilitate the return of the dried air or fluid to the air conditioning
or refrigeration system.
The inner wall portion 18 serves as a sleeve for receiving a portion
of an aluminum pipe or conduit 54 (FIG. 5) which communicates with
an outlet port (not shown) of the air conditioning or refrigeration
system. The inner wall portion 18 includes a beveled inner end surface
56 at the cap side thereof. The beveled inner end surface 56 tapers
radially inwardly in a direction toward the transverse web portion
24 to facilitate insertion of the aluminum pipe or conduit 54.
The inner wall portion 18 also includes a stepped inner surface
58 which defines an intermediate shoulder or flange 59. Thus, the
stepped inner surface 58 has two inner diameters D.sub.1 and D.sub.2
wherein D.sub.1 >D.sub.2. The inner diameter D.sub.1 is substantially
equal to or slightly larger than the outer diameter of the aluminum
pipe or conduit 54. The aluminum pipe or conduit 54 when inserted
into the inner wall portion 18 abuts against the shoulder 59 to
urge the desiccant container 10 downwardly within the dryer canister
40. Further, the inner wall portion 18 inner wall extension portion
44 and aluminum pipe or conduit 54 cooperate to define a continuous
axially extending passage 50 for returning the dried air or fluid
to the air conditioning or refrigeration system not shown. Since
a portion of the passage 50 is formed by the inner wall portion
18 and inner wall extension portion 44 the amount of aluminum tubing
or conduit 54 required to complete the passage 50 is desirably reduced
thereby providing cost reductions.
As best shown in FIGS. 2B and 5 the cap 16 conforms to the circular
shape of the cup 14. The cap 16 includes an intermediate planar
portion 60 a peripheral flanged portion 62 extending transversely
from an outer circumference of the intermediate planar portion 60
and a central flanged portion 64 extending transversely from an
inner circumference of the intermediate planar portion 60. A hole
66 extends through the central flanged portion 64 for receiving
the inner wall portion 18 of the cup 14 in an assembled state.
The peripheral flanged portion 62 includes an edge portion 68 which
cooperates with the nib groupings 34 to positively lock the cap
16 to the cup 14 as shown in FIG. 3B. That is, the outer diameter
of the edge portion 68 is greater than the inner diameter of the
nib groupings 34. Further, the edge portion 68 has an axial thickness
which is less than the axial spacing between adjacent nib groupings
34 so that the edge portion 68 can be positively retained between
axially adjacent nib groupings 34.
The cap 16 is sufficiently resilient so that when the cap 16 is
attached or detached from the cup 14 the edge portion 68 will pass
over the nib groupings 34 when sufficient force applied to the cap
16. In the preferred embodiment, the edge portion 68 is circumferentially
continuous. However, the edge portion 68 could be circumferentially
intermittent if desired.
The transverse web portion 24 of the cup 14 and the intermediate
planar portion 60 of the cap 16 are each perforated with a number
of symmetrically arranged ports or perforations (one of each shown
at 70 and 72 in FIGS. 2A and 2B, respectively) so that the intermediate
planar portion 60 and the transverse web portion 24 are each permeable
to the air or fluid to be dried. In the example shown, the ports
70 72 are arranged in concentric annular rows such that the two
inner rows have nine ports each and the outer row has eighteen ports.
The precise arrangement of the ports is not critical to the operation
of the desiccant container 10 as long as the desiccant 12 remains
contained and air or fluid (not shown) is allowed to enter the container
10 interact evenly with the desiccant 12 and exhaust from the container
10.
As shown in FIG. 3A, plies 74 76 of a permeable lining material
such as felted polyester or gauze are placed inside the chamber
26 near the transverse web portion 24 and the cap 16 to trap the
desiccant 12 in the container 10. The lining material must be permeable
to the air or fluid (not shown) to be dried but impermeable to the
particulate desiccant 12. If gauze is used, the mesh size of the
gauze must be significantly smaller than the grain size of the desiccant.
While the plies 74 76 are shown as circular liners or pads having
central holes 78 80 embracing and surrounding the inner wall portion
18 the plies may also be separate plies of a permeable capsule
or pouch (not shown), such as a torroidal capsule shaped to surround
the inner wall portion 18.
One method for fabricating the desiccant container 10 includes
the step of casting or injection molding the cup 14 to form a one-piece
plastic member having the inner and outer wall portions 18 22 connected
by the transverse web portion 24. One plastic suited for use in
casting the cup 14 is polypropylene. Polyethylene may also be used
but is not preferred. The cap 16 is likewise cast from plastic.
When the desiccant container is charged with the particulate desiccant
12 the first ply 76 of the permeable lining material is inserted
by sliding it down the inner wall portion 18 until positioned adjacent
the transverse web portion 24. The desiccant 12 is then charged
into the chamber 26 as by pouring. Since the chamber 26 is torroidal
and relatively shallow, the height of the desiccant 12 in the chamber
26 can be seen through the opening 28 so that the proper amount
of desiccant 12 is charged in a manual operation. Once the desiccant
12 is charged, the second ply 74 of the permeable lining material
is slid down the inner wall portion 18 against the desiccant 12.
The cap 16 is then inserted into the chamber 26 such that the inner
wall portion 18 extends through the central hole 66 in the cap 16.
As the cap 16 is urged downwardly toward the transverse web portion
24 the edge portion 68 of the cap 16 passes radially inwardly over
the axially spaced nib groupings 34 until the intermediate planar
portion 60 of the cap 16 abuts against the charged desiccant 12.
In a locked state, the cap 16 abuts against the second ply 74 and
charged desiccant 12 while the edge portion 68 thereof is lockingly
retained by at least one nib grouping 34.
Depending upon the specific amount of desiccant 12 contained in
the chamber 26 the edge portion 68 may be lockingly retained between
axially adjacent nib groupings 34 or the edge portion 68 may abut
against a nib grouping 34 positioned axially adjacent the edge portion
68 in the cap side direction.
Once the desiccant container 10 is assembled, it can then be inserted
into a dryer canister 40 as shown in FIG. 5. The outwardly flared
lip portion 38 resiliently bears against an inside surface 82 of
the dryer canister 40 to provide a snug fit of the desiccant container
10 in the dryer canister 40. The lip portion 38 also serves to prevent
air or fluid from bypassing the desiccant container 10 so as to
ensure passage thereof through the chamber 26 and over the desiccant
particles 12.
The aluminum pipe or conduit 54 is inserted into the inner wall
portion 18 until the pipe 54 abuts against the shoulder 59. The
desiccant container is then urged downwardly into the canister 40
until the legs 42 abut against the closed end portion 46 of the
canister 40. The legs 42 maintain the transverse web portion 24
at a predetermined distance away from the closed end portion 46
of the dryer canister 40. The legs 42 in cooperation with the closed
end portion 46 define a reservoir 84 for the dried air or fluid
which has passed through the desiccant 12.
In operation, the air or fluid to be dried passes over the desiccant
12 in the chamber 26 in the direction shown by Arrow A. The inner
wall extension portion 44 serves as an inlet for returning the dried
air or fluid from the reservoir 84 to the air conditioning or refrigeration
system via the passage 50 in the direction of Arrows B.
The cup 14 may be vibrator or bowl fed to a robotic arm for automatic
installation into the dryer canister 40. Furthermore, the plies
74 76 of lining material are relatively resistant to burn-through
in the cup 14 while the dryer canister 40 is being welded (not shown).
As stated previously, the cup 14 may be sized to fit snugly in the
canister 40 to inhibit bypass flow of air or fluid (not shown) to
be dried. The nib groupings 34 for detaining the cap 16 on the cup
14 are highly reliable so that the risk that desiccant will escape
and contaminate other parts of the air conditioning or refrigeration
system (not shown) is minimized.
Various changes or modifications in the invention described may
occur to those skilled in the art without departing from the true
spirit or scope of the invention. The above description of preferred
embodiments of the invention is intended to be illustrative and
not limiting, and it is not intended that the invention be restricted
thereto but that it be limited only by the true spirit and scope
of the appended claims. |