Abstrict An air drying cartridge for use in an air drying system is disclosed.
The air drying cartridge comprises a telescoping casing resiliently
self adjustable in height which has an inner cylindrical apertured
wall and an outer cylindrical apertured wall. The inner apertured
wall has a facing surface, an upper end and a lower end. The outer
apertured wall has a facing surface, an upper end and a lower end.
The facing surface of the inner apertured wall is disposed to face
the facing surface of the outer apertured wall thereby defining
an opening therebetween. The air drying cartridge also includes
a porous filter liner, a pair of sealing caps and a moisture absorbing
material for extracting moisture from air flowing through the air
drying cartridge. The porous filter liner is situated adjacent to
each of the facing surfaces within the opening. One of the pair
of sealing caps affixes to the upper ends of the apertured walls
and another affixes to the lower ends of the apertured walls. The
moisture absorbing material fills the opening between the filter
liners and sealed therein between the sealing caps. The telescoping
casing resiliently withstands compressive forces that would collapse,
rupture or otherwise distort prior art dryer cartridges. The desiccant
cartridge 30 exsiccates air more reliably and efficiently than prior
art desiccant devices.
Claims We claim:
1. An air drying cartridge for use in an air drying system comprising:
(a) a telescoping casing resiliently self adjustable in height
having an outer apertured wall assembly and an inner apertured wall
assembly wherein
(i) said apertured wall assemblies are concentrically disposed
to each other thereby defining an opening therebetween,
(ii) each of said apertured wall assemblies have a pair of concentrically
overlapping shells, each shell having an upper end and a lower end,
and
(iii) each of said apertured wall assemblies has a facing surface
so that said facing surfaces are disposed to face each other across
said opening;
(b) a porous filter liner situated adjacent to each of said facing
surfaces within said opening;
(c) a pair of sealing caps
(i) a first of which affixed to said upper ends of only one of
said shells from each of said upper and lower apertured wall assemblies,
and
(ii) a second of which affixed to said lower ends of only a remaining
one of said shells from each of said upper and lower apertured wall
assemblies,
so that said shells of said outer apertured wall assembly concentrically
overlap and slide longitudinally over each other and said shells
of said inner apertured wall assembly concentrically overlap and
slide longitudinally over each other; and
(d) a moisture absorbing material disposed within said opening
between said filter liners and sealed between said sealing caps
thereby rendering said telescoping casing resiliently self adjustable
in height;
wherein said telescoping casing resiliently withstands compressive
forces thereby enabling said air drying cartridge to resist damage
and wherein said moisture absorbing material extracts moisture from
air flowing through said air drying cartridge.
2. The air drying cartridge as recited in claim 1 wherein said
telescoping casing is resiliently self adjustable in height between
an upper limit height and a lower limit height.
3. The air drying cartridge as recited in claim 2 wherein said
opening of said air drying cartridge is filled with said moisture
absorbing material so that:
(a) said moisture absorbing material is under compression when
said telescoping casing is at said upper limit height thereby increasing
a quantity of said moisture absorbing material contained within
said opening and providing said air drying cartridge with enhanced
moisture collection capability; and
(b) said moisture absorbing material remains undamaged under compression
when said telescoping casing is reduced to at least said lower limit
height.
4. The air drying cartridge as recited in claim 1 wherein said
sealing caps include indicators for aligning said air drying cartridge
within a cartridge chamber of such air drying system.
5. The air drying cartridge as recited in claim 1 wherein said
filter liner is a polyester felt material capable of filtering particulates
of at least four microns in size from such air flowing therethrough.
6. The air drying cartridge as recited in claim 1 wherein said
moisture absorbing material is a pelletized alumina desiccant.
7. The air drying cartridge as recited in claim 1 wherein said
sealing caps are composed of at least one of black plastisol and
a comparable PVC material.
8. The air drying cartridge as recited in claim 1 wherein said
apertured walls are composed of a corrosion resistant material.
9. The air drying cartridge as recited in claim 8 wherein said
corrosion resistant material is stainless steel.
10. The air drying cartridge as recited in claim 1 wherein each
of said apertured walls has a plurality of apertures per square
inch such that in a range between 25 and 75 percent of the surface
area of each of said apertured walls is porous to such air flow.
11. The air drying cartridge as recited in claim 1 wherein said
air drying cartridge includes a means for preventing separation
of said exterior and outside shells of said outer and inner apertured
wall assemblies, respectively, from said interior and inside shells
of said outer and inner apertured wall assemblies, respectively,
thereby preventing spillage of said moisture absorbing material
from said opening.
12. An air drying cartridge for use in an air drying system comprising:
(a) a telescoping casing having an outer apertured wall assembly
and an inner apertured wall assembly wherein
(i) said outer apertured wall assembly has
(1) an exterior cylindrical shell having an upper end, and
(2) an interior cylindrical shell having a lower end and a facing
surface, and
(ii) said inner apertured wall assembly has
(1) an outside cylindrical shell having a lower end and a facing
surface, and
(2) an inside cylindrical shell having an upper end,
so that said facing surfaces are disposed to face each other thereby
defining an opening therebetween;
(b) a porous filter liner situated adjacent to each of said facing
surfaces within said opening;
(c) a pair of sealing caps one of which affixed to said upper ends
of said apertured wall assemblies and another of which affixed to
said lower ends of said apertured wall assemblies so that
(i) said exterior shell of said outer apertured wall assembly concentrically
overlaps and slides longitudinally over said interior shell of said
outer apertured wall assembly, and
(ii) said outside shell of said inner apertured wall assembly concentrically
overlaps and slides longitudinally over said inside shell of said
inner apertured wall assembly; and
(d) a moisture absorbing material disposed within said opening
between said filter liners and sealed between said sealing caps
thereby rendering said telescoping casing resiliently self adjustable
in height;
wherein said telescoping casing resiliently withstands compressive
forces thereby enabling said air drying cartridge to resist damage
and wherein said moisture absorbing material extracts moisture from
air flowing through said air drying cartridge.
13. The air drying cartridge as recited in claim 12 wherein said
telescoping casing is resiliently self adjustable in height between
an upper limit height and a lower limit height.
14. The air drying cartridge as recited in claim 13 wherein said
opening of said air drying cartridge is filled with said moisture
absorbing material so that:
(a) said moisture absorbing material is under compression when
said telescoping casing is at said upper limit height thereby increasing
a quantity of said moisture absorbing material contained within
said opening and providing said air drying cartridge with enhanced
moisture collection capability; and
(b) said moisture absorbing material remains undamaged under compression
when said telescoping casing is reduced to at least said lower limit
height.
15. The air drying cartridge as recited in claim 12 wherein said
sealing caps include indicators for aligning said air drying cartridge
within a cartridge chamber of such air drying system.
16. The air drying cartridge as recited in claim 12 wherein said
filter liner is a polyester felt material capable of filtering particulates
of at least four microns in size from such air flowing therethrough.
17. The air drying cartridge as recited in claim 12 wherein said
moisture absorbing material is a pelletized alumina desiccant.
18. The air drying cartridge as recited in claim 12 wherein said
sealing caps are composed of at least one of black plastisol and
a comparable PVC material.
19. The air drying cartridge as recited in claim 12 wherein said
apertured wall assemblies are composed of corrosion resistant material.
20. The air drying cartridge as recited in claim 19 wherein said
corrosion resistant material is stainless steel.
Description FIELD OF THE INVENTION
The present invention generally relates to an air drying element
for use in a compressed air system. More particularly, the present
invention pertains to an air drying cartridge which includes a telescoping
stainless steel casing having both an inner and an outer apertured
cylindrical wall assembly, a porous polyester filter media disposed
adjacent to and lining a facing surface of each of the inner and
outer apertured cylindrical wall assemblies, a pelletized desiccant
material contained between each polyester media liner, and a pair
of sealing caps one of which covering each end of the casing so
that moisture is effectively removed from compressed air as it passes
radially through the air drying cartridge.
BACKGROUND OF THE INVENTION
It is documented in pertinent prior art and generally well known
in germane technical fields that a Westinghouse Air Brake Company
C-1 air dryer is designed to remove moisture vapor from a stream
of compressed air in which the air dryer is placed. In practice,
the C-1 air dryer employs a single tower moisture removal, cleansing
and regenerating system containing a desiccant material to absorb
the moisture from the air. Specifically, as the compressed air passes
through the air dryer, the desiccant material absorbs and retains
the moisture suspended therein until the compressor stops operating.
By design, the C-1 air dryer then automatically flushes a quantity
of the dried compressed air back through the desiccant material
to draw out the absorbed moisture. The stream of compressed air
and the revaporized moisture it carries is then discharged to the
atmosphere thereby regenerating the desiccant material.
Prior to the present invention, the C-1 air dryer used either a
preformed desiccant block or a desiccant filled cartridge to perform
the air drying function. Both of these desiccant devices proved
disadvantageous in one or more respects.
The preformed desiccant block is basically a hollow, cylindrically
shaped compressed block of calcium chloride (CaCl.sub.2). This preformed
desiccant block inserts into a desiccant chamber in the C-1 air
dryer and is sealed therein by an annular rubber gasket on each
end. Though the preformed desiccant block removes moisture from
the compressed air, it presents a number of shortcomings. First,
the desiccant block has a relatively small surface area which limits
its moisture-collection capability. Second, the desiccant block
tends to disintegrate into a relatively fine grit while in service
which, if not trapped by a smaller, secondary filter, contaminates
the compressed air system. In particular, the introduction of grit
into the air stream could adversely affect the operation of various
components of an air brake system disposed on a railway vehicle.
Third, the desiccant block is relatively fragile and does not withstand
rough handling. It can endure only moderate compressive loads before
breaking up into a number of separate pieces. Once the desiccant
breaks up, the desiccant block becomes unsuitable for further use
because its moisture absorbing qualities are substantially impaired
and the risk of contamination of, if not damage to, the compressed
air system would become reality otherwise.
The typical desiccant filled cartridge as set forth in U.S. Pat.
No. 5423129 teaches a desiccant device that overcomes most of
the shortcomings of the preformed desiccant block. Though a substantial
improvement upon the desiccant block, the typical desiccant cartridge
likewise has its disadvantages.
The drawings of U.S. Pat. No. 5423129 illustrate how the typical
desiccant cartridge is used within the C-1 air dryer system. FIG.
1 shows a cross-sectional view of the C-1 air dryer containing the
desiccant cartridge, alternately referred to as a dryer element.
The C-1 air dryer also includes a discharge air filter element,
a discharge check valve, a purge volume, a purge check valve with
a choke, and a sump volume. The dryer element of the C-1 air dryer,
according to this reference, is a hollow, cylindrically shaped radial
flow cartridge member which removes moisture or water vapor from
compressed air passing through it.
Referring now to FIG. 2 the dryer element is shown in greater
detail in this slightly enlarged view. It includes an outer perforated
cylindrical shell or jacket which is capped by a pair of annular
end sealing caps or members. The outer shell is a flat piece of
stainless steel metal punched with a plurality of holes and then
formed into a cylinder. The annular end sealing caps are composed
of rubber.
In viewing FIGS. 2 3 4 and 5 of this reference, it is apparent
that the rubber end caps are cup-shaped members having two flanges
or rims, respectively. The outer flanges of the rubber end caps
are molded to the exterior upper and lower ends of the outer perforated
shell. As shown in FIGS. 4 and 5 the air drying element further
includes an inner perforated cylindrical shell or jacket which is
also constructed of stainless steel or some other corrosion-resistant
material. The inner flanges of the rubber end caps are molded to
the interior upper and lower ends of the inner perforated shell.
FIGS. 2 3 4 and 5 also illustrate that the outer surfaces of
each the rubber end caps are provided with outer annular beads and
inner annular beads which apparently serve as sealing gaskets.
During assembly of the desiccant cartridge, the bottom end cap
is molded to the lower ends of the perforated shells. After molding,
a polyester felt support layer is placed against the inner surface
of the outer perforated cylindrical shell and a similar polyester
felt layer is situated against the outside surface of the inner
perforated cylindrical shell. After the felt layers are positioned,
a loose desiccant material is packed in the opening between the
two felt layers. After the opening is filled, the desiccant cartridge
is sealed by molding the top rubber end cap to the upper ends of
the outer and inner perforated shells. In conjunction with the annular
beads, the rubber end caps function not only to seal the ends of
the desiccant cartridge but also to direct appropriately the air
therethrough.
The outer and inner perforated shells provide a certain degree
of physical strength to the prior art desiccant cartridge taught
in U.S. Pat. No. 5423129. Experience has shown, however, that
the prior art cartridge does not always withstand the compressive
forces that its physical environment inflicts upon it. Rigid by
design, these shells in practice often buckle, collapse, rupture
or otherwise distort when subject to such compressive forces. Consequently,
as with the prior art preformed desiccant block, desiccant material
leaks into and contaminates the compressed air system. Conceivably,
pieces of the perforated shells could break off and likewise adversely
affect, if not damage, the pneumatic system. For these reasons,
a new and improved desiccant cartridge that does not exhibit the
failure modes of the prior art desiccant devices would be very well
received in the field of pneumatics
OBJECTS OF THE INVENTION
It is, therefore, one of the primary objects of the present invention
to provide a new and improved telescoping desiccant cartridge for
use in a compressed air system.
Another object of the present invention to provide a new and improved
telescoping air drying desiccant cartridge that is self adjustable
in height so as to resiliently withstand compressive forces that
would collapse, rupture or otherwise damage prior art dryer cartridges.
Yet another object of the present invention is to provide a unique
telescoping air drying element which effectively removes moisture
and dirt in an air brake system.
Still another object of the present invention is to provide an
air dryer and filter element including a telescoping hollow, cylindrically
shaped apertured shell, a felt media, and a pelletized molecular
sieve desiccant therein for use in compressed air system.
Even another object of the present invention is to provide a moisture
absorbing cartridge having an inner pelletized hydrated alumina
desiccant material, an intermediate polyester felt filtering media,
and an outer apertured telescoping stainless steel cylinder container
which is capped by annular sealing caps.
A further object of the present invention is to provide an air
drying element, for use in a compressed air system, comprising a
telescoping apertured shell member, a porous filter media conforming
to the facing boundaries of the apertured shell member, a pelletized
desiccant material disposed within the porous filter media, and
a pair of cap members sealing the ends of the apertured shell member
wherein moisture is absorbed from air flowing through and by the
pelletized desiccant material of the air drying element.
Yet a further object of the present invention is to provide a desiccant
cartridge, for an air dryer, comprising a casing having an inner
telescoping cylindrical apertured wall and an outer telescoping
cylindrical apertured wall, a filter liner situated adjacent the
facing surfaces of the inner and outer apertured walls, a pelletized
moisture absorbing material disposed between the filter liner of
the facing surfaces of the inner and outer apertured walls, and
a sealing cap covering the respective ends of the casing whereby
the incoming air passes through the outer and inner apertured walls,
the filter liner, and the pelletized moisture absorbing material
to extract moisture contained therein.
Yet another object of the present invention is to provide an improved
desiccant cartridge which is simple in construction, efficient in
operation, economical in cost, reliable in use, durable in service,
and easy to install.
In addition to the objects and advantages of the present invention
set forth above, various additional objects and advantages of the
telescoping desiccant cartridge will become more readily apparent
to those persons who are skilled in the air compressor art from
the following more detailed description of the invention, particularly,
when such description is taken in conjunction with the attached
drawings and with the appended claims.
SUMMARY OF THE INVENTION
In a presently preferred embodiment, the present invention provides
an air drying cartridge for use in an air drying system. The air
drying cartridge includes a telescoping casing having an outer apertured
wall assembly and an inner apertured wall assembly. The outer apertured
wall assembly has an exterior cylindrical shell and an interior
cylindrical shell. The exterior shell has an upper end and the interior
shell has a lower end and a facing surface. The inner apertured
wall assembly has an outside cylindrical shell and an inside cylindrical
shell. The outside shell has a lower end and a facing surface and
inside shell has an upper end. The facing surfaces are disposed
to face each other thereby defining an opening therebetween. The
exterior and outside shells of the outer and inner apertured wall
assemblies, respectively, concentrically overlap and slide longitudinally
over the interior and inside shells of the outer and inner apertured
wall assemblies, respectively. The air drying cartridge also includes
a porous filter liner, a pair of sealing caps and a moisture absorbing
material. The porous filter liner is situated against each of the
facing surfaces within the opening. One of the pair of sealing caps
is affixed to the upper ends of the apertured wall assemblies and
another is affixed to the lower ends of the apertured wall assemblies.
The moisture absorbing material extracts moisture from air flowing
through the air drying cartridge. The moisture absorbing material
is disposed within and fills the opening between the filter liners
and is sealed between the sealing caps thereby rendering the telescoping
casing resiliently self adjustable in height. The telescoping casing
resiliently withstands compressive forces thereby enabling the air
drying cartridge to resist collapse, rupture or other damage that
would adversely affect prior art dryer cartridges.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view, partly in section, of an air
dryer apparatus employing a prior art desiccant cartridge.
FIG. 2 is a slightly enlarged view of the prior art desiccant cartridge
or air drying element illustrated in FIG. 1.
FIG. 3 is a top plan view of the prior art desiccant cartridge
of FIG. 2.
FIG. 4 is a partial cross-sectional view of the prior art desiccant
cartridge.
FIG. 4a is a magnified view of a prior art outer perforated shell,
filter liner and desiccant material of the desiccant cartridge of
FIG. 4.
FIG. 5 is a cross-sectional view taken along line V--V of FIG.
4.
FIG. 6 is a side elevational view of a telescoping desiccant cartridge
according to the present invention.
FIG. 6a-1 is an enlarged cross-sectional view of the telescoping
desiccant cartridge of FIG. 6 illustrating an inner apertured wall
assembly.
FIG. 6a-2 is a magnified view of the inner apertured wall assembly
of FIG. 6a-1 along with a porous filter liner and a desiccant material.
FIG. 6b-1 is an enlarged cross-sectional view of the telescoping
desiccant cartridge of FIG. 6 illustrating an outer apertured wall
assembly.
FIG. 6b-2 is a magnified view of the outer apertured wall assembly
of FIG. 6b-1 along with a porous filter liner and the desiccant
material.
FIG. 7 is a top plan view of the desiccant cartridge of FIG. 6
showing a top sealing cap and indicators for aligning the desiccant
cartridge within a cartridge chamber of the air dryer apparatus.
FIG. 8 is a bottom plan view of the desiccant cartridge of FIG.
6 showing a bottom sealing cap and indicators for aligning the desiccant
cartridge within the cartridge chamber of the air dryer apparatus.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 through 5 illustrated therein are the essential
details of a C-1 air dryer apparatus including a prior art desiccant
cartridge 2 alternately referred to as a dryer element 2. FIG.
1 illustrates a cross-sectional view of such C-1 air dryer 1 including
air dryer casing 10. Such C-1 air dryer 1 includes a cartridge chamber
containing the prior art desiccant cartridge 2. Such C-1 air dryer
also includes a discharge air filter element 3 a discharge check
valve 4 a purge volume 5 a purge check valve 6 with a choke 9
and a sump volume 7.
The following serves as a brief explanation of the various parts
of such C-1 air dryer apparatus 1 into which the desiccant cartridge
of the present invention inserts. Such C-1 air dryer apparatus 1
is designed to provide dried, compressed air to the various pneumatic
systems, including the air brake system, of a railroad train consist.
Such air dryer apparatus 1 receives from an air compressor (not
shown) a supply of air. The moisture laden, compressed air passes
into the sump volume 7 flows through a first opening 21 into a
first chamber 22 then a passageway 23 and moves radially through
the desiccant cartridge 2. The desiccant cartridge plays the key
role in the system in that it absorbs moisture and traps other suspended
particulates (e.g., dust, dirt, etc.) as the compressed air flows
through such air dryer apparatus 1. Once such moisture and such
particulates are extracted from the air stream, the cleansed, dry
compressed air flows through purge check valve 6 through both a
second chamber 24 and a second opening 25 into the purge volume
5.
The purge volume 5 is capable of holding approximately five-hundred
cubic inches (500 in.sup.3) of compressed dry air. When the air
compressor is cycled to the "off" state, the dry compressed
air then contained within the purge volume 5 passes slowly in the
reverse direction through the choke 9 of the check valve 6 and through
the desiccant cartridge 2 so that the collected moisture readily
evaporates in the passing dry air and eventually exhausts to atmosphere.
This purging of dry air back through the system serves to dry out
and thus rejuvenate the desiccant cartridge 2. The desiccant cartridge
2 is then ready to remove again moisture from the incoming compressed
air when the compressor is cycled to the "on" state.
The discharge filter 3 is integrally housed within the dryer casing
10 as a precautionary measure to reduce even further the possibility
of contamination of the pneumatic systems. The discharge air filter
3 thus serves as a backup to the desiccant cartridge 2 in the event
that the desiccant cartridge 2 deteriorates or otherwise breaks
up. If the desiccant cartridge 2 does deteriorate, however, the
discharge air filter 3 would at least for a limited time trap loose
desiccant particles as well as other contaminants while permitting
the flow of dry compressed air from purge volume 5 to a discharge
chamber 26. Discharge chamber 26 connects to a supply valve (not
shown). The flow of dry air continues through discharge chamber
26 through discharge check valve 4 through a terminal chamber 27
to a suitable air pressure reservoir {e.g., main reservoir} (not
shown). Terminal chamber 27 also connects to a governor device (not
shown).
The check valves 46 at either end of the such C-1 air dryer apparatus
1 control the entry and exit of air pressure from the air dryer
system 1. At one end, the purge check valve 6 via the choke 9 permits
unrestricted flow of moist, compressed air into the air dryer apparatus
1 during the compressor "ON" cycle. During the compressor
"OFF" cycle (i.e., the purge cycle), the purge valve 6
controls the rate at which dry air flows from the purge volume 5
to exsiccate the desiccant cartridge 2. At the other end, the discharge
check valve 4 prevents the backward flow of air from the air pressure
reservoir to the purge volume 5 during the purge cycle.
Referring to FIGS. 6 through 8 illustrated therein are the essential
details of a presently preferred embodiment of the instant invention--a
telescoping desiccant cartridge 30 for use in the air drying system
1 of FIG. 1. As illustrated in FIGS. 6 through 6b-2 the telescoping
desiccant cartridge 30 includes a telescoping casing 31. The telescoping
casing 31 has an inner apertured wall assembly 40 and an outer apertured
wall assembly 60. The inner apertured wall assembly 40 has an outside
cylindrical shell 51 and an inside cylindrical shell 41. The outside
shell 51 of the inner wall assembly 40 has a lower end 54 and a
facing surface 52. The inside shell 41 of the inner wall assembly
40 has a upper end 43. Similarly, the outer apertured wall assembly
60 has an exterior cylindrical shell 61 and an interior cylindrical
shell 71. The exterior shell 61 of the outer wall assembly 60 has
an upper end 64 and the interior shell 71 has a lower end 73 and
a facing surface 72. The facing surfaces 5272 of the inner and
outer wall assemblies 4060 respectively, are disposed to face
each other thereby defining an opening 90 therebetween. As is best
illustrated in FIGS. 6a-1 through 6b-2 the exterior shell 61 of
the outer apertured wall assembly 60 concentrically overlaps and
slides longitudinally over the interior shell 71 of the outer apertured
wall assembly 60. Likewise, the outside shell 51 of the inner apertured
wall assembly 40 concentrically overlaps and slides longitudinally
over the inside shell 41 of the inner apertured wall assembly 40.
Referring generally again to FIGS. 6 through 6b-2 the telescoping
desiccant cartridge 30 also includes a porous filter liner 8182
a pair of sealing caps 9397 and a moisture absorbing material 85.
The porous filter liner 8182 situates adjacent to and against each
of the facing surfaces 5272 respectively, within the opening 90.
A first of the sealing caps 93 affixes to the upper ends 4364 of
the apertured wall assemblies 4060. Likewise, a second of the sealing
caps 97 affixes to the lower ends 5473 of the apertured wall assemblies
4060. The moisture absorbing material 85 fills the opening 90 between
the filter liners 8182 and is sealed between the sealing caps 9397.
The sealing caps 9397 also provide a snug fit for the desiccant
cartridge 30 within the air dryer system 1.
The construction of the telescoping desiccant cartridge 30 described
above makes the instant invention structurally durable and flexible,
characteristics absent from prior art desiccant cartridges. Prior
art dryer elements often succumb structurally and operationally
to compressive forces naturally visited upon such air dryer apparatuses
1. Their rigid casings often rupture or collapse causing release
of the desiccant material or casing fragments or both into the compressed
air stream which wreaks havoc on the various pneumatic systems.
The slidable, concentrically overlapping dual shell design of the
two apertured wall assemblies 4060 combined with the compressibility
of the moisture absorbing material 85 renders the instant telescoping
desiccant cartridge 30 resiliently self adjustable in height. The
telescoping cartridge 30 thus resiliently withstands such compressive
forces that would collapse, rupture or otherwise damage prior art
dryer elements. Consequently, the desiccant cartridge 30 can exsiccate
air more reliably and efficiently than prior art desiccant devices.
The air drying cartridge 30 can be designed for air dryer apparatuses
1 of varying sizes and to handle various degrees of compressive
loads. In any given design, the telescoping desiccant cartridge
30 is resiliently self adjustable in height between an upper limit
height and a lower limit height. During assembly, the opening 90
of the air drying cartridge 30 should typically be filled with the
moisture absorbing material 85 when the telescoping casing 31 is
at or above the upper limit height. Preferably, the moisture absorbing
material 85 is under compression when the telescoping casing 31
is at the upper limit height. Increasing the quantity of moisture
absorbing material 85 within the opening 90 causes a corresponding
increase in the moisture collection capability of the air drying
cartridge 30 as a result of the increase in effective surface area.
(As is well known in the filter art, however, there is a tradeoff
between the amount of moisture absorbing material that can be packed
into the desiccant cartridge and the ability of the moisture laden
material to withstand compressive forces without becoming damaged.)
The air drying cartridge 30 and the moisture absorbing material
85 contained therein are designed so that they remain undamaged
under compression when the telescoping casing 31 is reduced to at
least the lower limit height.
As is well known to persons skilled in the pneumatic arts, various
materials may used to make the critical filtering elements of the
instant telescoping desiccant cartridge 30. The porous filter liner
8182 is a needled polyester felt or like material capable of filtering
particulates of at least four microns (4.mu.) in size from the air
flowing through air drying cartridge 30.
The moisture absorbing material 85 is a mesh white activated alumina
desiccant, preferably in pelletized form. For example, the pelletized
desiccant may consist of approximately three sixteenths inch (3/16")
sized beads or spheres of the activated alumina desiccant. The quantity
of desiccant material 85 required to fill the opening 90 is approximately
two and one-half pounds (2.5 lbs.) The apertured wall assemblies
4060 are composed of a corrosion resistant material. The preferred
corrosion resistant material is stainless steel or a plastic of
similar strength. If stainless steel is chosen, each of the shells
41 51 61 and 71 may be formed from a flat piece of such metal
punched or perforated with a plurality of apertures. The flat, perforated
metal can then be looped into a cylinder with its longitudinal ends
pinched, welded or similarly secured together to form a rigid, cylindrically
shaped shell.
Referring now to FIGS. 7 and 8 the top and bottom sealing caps
9397 each include alignment indicators 94 and 95 respectively,
to be used for aligning the air drying cartridge 30 within the cartridge
chamber of such air dryer system apparatus 1. The sealing caps 9397
maybe composed of any one of a variety of materials and are preferably
molded to the respective upper and lower ends of the apertured wall
assemblies 4060. Known to practitioners of the pneumatic arts,
whatever material is ultimately chosen, it must capable of providing
a sufficiently tight seal to prevent leakage of air from the upper
and lower ends of the apertured walls assemblies. A preferred material
for the sealing caps is at least one of black plastisol and a comparable
PVC material.
As an added feature of the instant invention, the air drying cartridge
30 includes a means (not shown) for preventing separation of the
exterior 61 and outside 51 shells of the outer 60 and inner 40 apertured
wall assemblies, respectively, from the interior 71 and inside 41
shells of the outer 60 and inner 40 apertured wall assemblies, respectively.
Though not necessary while the telescoping desiccant cartridge 30
is encased within the cartridge chamber of such air dryer apparatus
1 the separation prevention means is useful to prevent inadvertent
opening of and spillage of the desiccant 85 from the air drying
cartridge 30 during handling of the instant cartridge 30.
While the presently preferred embodiment and related aspects for
carrying out the instant telescoping desiccant cartridge 30 have
been set forth in detail in accordance with the Patent Act, those
persons skilled in the pneumatic arts to which this invention pertains
will recognize that various alterations and changes could be made
to the instant invention without departing from the spirit and scope
of the appended claims.
Accordingly, to promote the progress of science and useful arts,
we secure for ourselves by Letters Patent exclusive rights to all
subject matter embraced by the following claims for the time prescribed
by the Patent Act. |