Abstrict A casing assembly of a desiccant housing houses desiccant in an
air dryer system. The casing assembly includes a casing portion,
a retainer, two porous plates, and a mechanism for compacting the
desiccant. The casing portion defines a channel between two sleeves
that channels moisture-bearing air from an inlet of a head end out
a tail end of the casing portion. An inner sleeve defines a flow
chamber between the ends. The head end features an inner seat face
that seals against an inner sealing flange of a main portion of
the housing. The head end features an outer seat face that connects
to an outer sealing flange of the main portion. The inlet communicates
with a supply port of the main portion from which the moisture-bearing
air is received during a drying mode of operation of the system.
An outlet of the head end communicates with a delivery port of the
main portion out of which dried air is directed during the drying
mode. The retainer affixes to the inner sleeve within the flow chamber
at the head end. One plate abuts an interior side of the retainer
within the flow chamber. The other plate is slidably disposed within
the flow chamber near the tail end. The compacting means connects
to an inner face of the tail end and abuts the other plate thereby
compacting the desiccant between the porous plates. The tail end
features an outer seat face that connects to a cover portion of
the housing.
Claims I claim:
1. A casing assembly of a desiccant element housing for housing
a desiccant element in a gas dryer system, said casing assembly
comprising:
(a) a casing portion having an inner and an outer sleeve with a
channel defined between said sleeves for channeling moisture-bearing
gas from an inlet port of a head end of said casing portion out
a tail end of said casing portion, said inner sleeve defining a
flow chamber extending from said tail end to said head end;
(b) said head end featuring (i) an inner seat face for sealing
against an inner sealing flange of a main portion of said housing
and (ii) an outer seat face for sealingly connecting to an outer
sealing flange of said main portion of said housing so that (A)
said inlet port communicates with a supply port of said main portion
from which said moisture-bearing gas is received during a drying
mode of operation of said gas dryer system and (B) an outlet port
of said head end communicates with a delivery port of said main
portion out of which dried gas is directed during said drying mode;
(c) a retaining means for affixing to said inner sleeve at said
head end thereof within said flow chamber;
(d) a head end porous plate abutting an interior facing side of
said retaining means within said flow chamber;
(e) a tail end porous plate slidably disposed within said flow
chamber of said inner sleeve near said tail end;
(f) a means, connected to said tail end and abutting said tail
end porous plate, for compacting said desiccant element within said
flow chamber between said porous plates; and
(g) said tail end featuring an outer seat face for sealingly connecting
to a sealing flange of a cover portion of said housing so that said
moisture-bearing gas channeled out said tail end redirects into
said flow chamber for drying by said desiccant element during said
drying mode of operation of said gas dryer system.
2. The casing assembly recited in claim 1 wherein said means for
compacting said desiccant element includes:
(a) a spring retaining plate affixed to an inner face of said tail
end; and
(b) a spring compressively situated between said spring retaining
plate and said tail end porous plate so as to maintain a compressive
force upon said desiccant element disposed in said flow chamber
between said porous plates.
3. The casing assembly recited in claim 2 wherein said spring retaining
plate affixes via a plurality of screws to said inner face of said
tail end.
4. The casing assembly recited in claim 1 wherein said retaining
means is a retaining ring that affixes within a groove defined within
said inner sleeve at said head end thereof.
5. The casing assembly recited in claim 1 wherein said inner and
said outer sleeves of said casing portion connect to each other
via a plurality of connecting tabs.
6. The casing assembly recited in claim 1 wherein:
(a) said outer seat face of said head end connects via a plurality
of bolts to said outer sealing flange of said main portion; and
(b) said outer seat face of said tail end connects via a plurality
of bolts to said sealing flange of said cover portion.
7. The casing assembly recited in claim 1 wherein:
(a) said inner seat face of said head end seals against said inner
sealing flange of said main portion via an o-ring retained in a
groove defined in said inner seat face;
(b) said outer seat face of said head end seals against said outer
sealing flange of said main portion via an o-ring retained in a
groove defined in said outer seat face; and
(c) said outer seat face of said tail end seals against said sealing
flange of said cover portion via an o-ring retained in a groove
defined in said sealing flange of said cover portion.
8. The casing assembly recited in claim 7 wherein:
(a) said outer seat face of said head end connects via a plurality
of bolts to said outer sealing flange of said main portion; and
(b) said outer seat face of said tail end connects via a plurality
of bolts to said sealing flange of said cover portion.
9. The casing assembly recited in claim 1 wherein said cover portion
defines a purge port through which a stream of remoisturized gas
is expelled from said desiccant element housing during a purge mode
of operation of said gas dryer system.
10. A casing portion for forming a casing assembly of a desiccant
element housing of a gas dryer system, said casing assembly including
a retaining ring, a pair of porous plates and a means for compacting
a desiccant element housed within said casing assembly, said casing
portion comprising:
(a) a pair of concentric sleeves interconnected with a plurality
of tabs with a channel defined between said sleeves, said channel
extending from an inlet port of a head end of said casing portion
to a tail end of said casing portion, an inner one of said sleeves
defining a cylindrical flow chamber extending from said tail end
to said head end;
(b) said head end featuring (i) an inner seat face for sealing
against an inner sealing flange of a main portion of said housing
and (ii) an outer seat face for sealingly connecting to an outer
sealing flange of said main portion of said housing so that (A)
said inlet port is communicable with a supply port of said main
portion and (B) an outlet port of said head end is communicable
with a delivery port of said main portion;
(c) said head end defining within said inner sleeve a groove into
which is affixable a retaining ring having an interior facing side
against which one of said porous plates is abuttable;
(d) said tail end featuring an inner face to which is affixable
said compacting means such that said compacting means compresses
the other of said porous plates into said desiccant element so as
to maintain a compressive force upon said desiccant element between
said porous plates in said flow chamber; and
(e) said tail end featuring an outer seat face for sealingly connecting
to a sealing flange of a cover portion of said housing.
11. The casing portion recited in claim 10 wherein said inner face
of said tail end defines a plurality of screw holes for affixing
thereto said compacting means via screws.
12. The casing portion recited in claim 10 wherein:
(a) said outer seat face of said head end is connectable via a
plurality of bolts to said outer sealing flange of said main portion;
and
(b) said outer seat face of said tail end is connectable via a
plurality of bolts to said sealing flange of said cover portion.
13. The casing portion recited in claim 10 wherein:
(a) said inner seat face of said head end defines a groove into
which an o-ring is retainable for sealing said inner seat face against
said inner sealing flange of said main portion; and
(b) said outer seat face of said head end defines a groove into
which an o-ring is retainable for sealing said outer seat face against
said outer sealing flange of said main portion.
14. The casing portion recited in claim 13 wherein:
(a) said outer seat face of said head end is connectable via a
plurality of bolts to said outer sealing flange of said main portion;
and
(b) said outer seat face of said tail end is connectable via a
plurality of bolts to said sealing flange of said cover portion.
15. A cover portion of a desiccant element housing of a gas dryer
system, said cover portion comprising a cover body having a sealing
flange for sealingly connecting to an outer seat face of a tail
end of a casing portion of said housing, said cover body defining
a focal chamber and a purge port such that said focal chamber extends
from said sealing flange to said purge port, said focal chamber
for (i) redirecting moisture-bearing gas received from a channel
of said casing portion into a flow chamber of said casing portion
during a drying mode of operation of said gas dryer system and (ii)
for directing remoisturized gas received from said flow chamber
to said purge port for expulsion to atmosphere during a purge mode
of operation of said gas dryer system.
16. The cover portion recited in claim 15 wherein said sealing
flange defines a groove into which an o-ring is retainable for sealing
said sealing flange against said outer seat face of said tail end
of said casing portion of said housing.
17. The cover portion recited in claim 16 wherein said sealing
flange connects via a plurality of bolts to said outer seat face
of said tail end of said casing portion of said housing.
Description CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to application Ser. No. 08/713782
now U.S. Pat. No. 5715621 and Ser. No. 08/713471 now U.S. Pat.
No. 5689893 entitled Regenerative Desiccant Air Dryer and Desiccant
Canister With Positioning Bore, respectively, both filed Sep. 13
1996 and allowed thereafter. These patent applications are assigned
to the assignee of the present invention, and their teachings are
incorporated into the present document by reference.
FIELD OF THE INVENTION
The present invention generally relates to a system for drying
air supplied by a compressor unit for use in a pneumatic system.
More particularly, the invention pertains to a casing assembly of
a desiccant housing for housing a desiccant element in an air dryer
system. Still more particularly, the invention pertains to a casing
assembly featuring a casing portion that at a head end sealingly
connects to a main portion of the housing and at a tail end sealingly
connects to a cover portion of the housing such that all three portions
form the desiccant housing.
BACKGROUND OF THE INVENTION
Air dryer systems remove moisture vapor from a stream of compressed
air into which the air dryer system is incorporated. An air dryer
system employs one or more standard desiccant element housings each
of which contains a moisture absorbing material (hereafter desiccant)
to extract the moisture from the air. In air dryer systems having
one desiccant element housing, the housing through its desiccant
absorbs the moisture suspended in the compressed air passing through
it until the compressor stops operating after a preset time. By
design, this type of air dryer system then automatically flushes
a quantity of the dried compressed air stored in a purge volume
back through the housing to draw out the moisture contained in the
desiccant. The stream of compressed air with the revaporized moisture
it carries is then discharged to the atmosphere thereby regenerating
the desiccant contained in the desiccant element housing.
In air dryer systems having two desiccant element housings, the
air dryer system alternately switches between two cycles. In the
first cycle, the air dryer system removes moisture from air passing
through a first desiccant element housing while purging from a second
desiccant element housing moisture it has previously collected.
In the second cycle, the air dryer system removes moisture from
air passing through the second desiccant element housing while purging
from the first desiccant element housing moisture it has previously
collected.
Prior art air dryer systems generally employ the standard desiccant
element housing(s) to perform the air drying function. When it comes
time to replace the desiccant within a housing, however, the design
of the standard housing typically requires that nearly all of the
housing has to be removed to get access to the desiccant. In the
type of standard desiccant element housing in which the desiccant
is contained within a canister or comes in block form, the standard
housing generally retains the desiccant through a tight press fitting
or interference fitting of the desiccant within the housing. The
fit of the desiccant into the housing is so tight that it typically
must be forcibly inserted into the housing during installation and
forcibly pulled from the housing during removal with the aid of
the appropriate tools.
The standard desiccant housing design thus presents a number of
shortcomings. First, the process of installing the desiccant into
the housing is quite strenuous and takes too much time. Second,
in those standard desiccant housings in which the desiccant is contained
within a canister, one can not be sure whether the canister is properly
aligned within the housing so that the top of the canister seats
against and makes an air tight seal with a sealing face of the housing.
Third, removal of such a canister from the housing is often quite
difficult because of its tight fit within the housing. For these
reasons, a novel casing assembly of a desiccant element housing
that does not exhibit the these disadvantages is described and claimed
in this document.
The present invention can be applied to a wide variety of pneumatic
systems. Typical of the types of pneumatic systems to which the
present system could be applied include the pneumatic brake systems
of passenger transit and freight railroad trains, subway trains
and various other types of rail related transportation systems.
Further examples include the pneumatic brake systems of various
truck transport vehicles. Other types of pneumatic systems to which
the present invention could be applied may indeed be found outside
the transportation field.
It should be noted that the foregoing background information is
provided to assist the reader in understanding the present invention.
Accordingly, any terms used herein are not intended to be limited
to any particular narrow interpretation unless specifically stated
otherwise in this document.
OBJECTIVES OF THE INVENTION
It is, therefore, one of the primary objectives of the present
invention to provide a casing assembly of a desiccant housing for
housing a desiccant element in an air dryer system.
Another objective of the present invention is to provide a casing
assembly featuring a casing portion that at a head end sealingly
connects to a main portion of the desiccant housing and at a tail
end sealingly connects to a cover portion of the housing such that
all three portions form the desiccant housing.
Yet another objective of the present invention is to provide a
casing assembly featuring a casing portion that at a tail end easily
connects sealingly to a cover portion of a desiccant housing so
that the desiccant element housed in the assembly can be easily
accessed and removed via the cover portion of the housing.
Still another objective of the present invention is to provide
a casing assembly of a desiccant housing featuring a means for compacting
the desiccant between porous plates in a flow chamber defined by
the casing assembly so that the desiccant distributes uniformly
within the flow chamber.
In addition to these objectives and advantages, various other objectives
and advantages will become more readily apparent to persons skilled
in the air dryer system art from a reading of the detailed description
section of this document. The other objectives and advantages will
become particularly apparent when the detailed description is considered
in conjunction with the attached drawings and with the appended
claims.
SUMMARY OF THE INVENTION
In a presently preferred embodiment, the present invention provides
a casing assembly of a desiccant element housing for housing a desiccant
element in an air dryer system. The casing assembly includes a casing
portion, a retaining means, a head end porous plate, a tail end
porous plate and a means for compacting the desiccant element. The
casing portion has inner and outer sleeves with a channel defined
between the sleeves. The channel channels moisture-bearing air from
an inlet port of a head end of the casing portion out a tail end
of the casing portion. The inner sleeve defines a flow chamber extending
from the tail end to the head end. The head end features an inner
seat face for sealing against an inner sealing flange of a main
portion of the desiccant element housing. The head end also features
an outer seat face for sealingly connecting to an outer sealing
flange of the main portion of the desiccant element housing. This
allows the inlet port to communicate with a supply port of the main
portion from which the moisture-bearing air is received during a
drying mode of operation of the air dryer system. It also allows
an outlet port of the head end to communicate with a delivery port
of the main portion out of which dried air is directed during the
drying mode. The retaining means affixes to the inner sleeve within
the flow chamber at the head end. The head end porous plate abuts
an interior facing side of the retaining means within the flow chamber.
The tail end porous plate is slidably disposed within the flow chamber
of the inner sleeve near the tail end. The compacting means is connected
to an inner face of the tail end and abuts the tail end porous plate.
It compacts the desiccant element within the flow chamber between
the porous plates. The tail end also features an outer seat face
for sealingly connecting to a sealing flange of a cover portion
of the desiccant element housing. The cover portion redirects the
moisture-bearing air channeled out the tail end into the flow chamber
for drying by the desiccant element during the drying mode of operation
of the air dryer system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a casing assembly of a desiccant
element housing according to the present invention.
FIG. 2a is a cross-sectional view of a casing portion of the casing
assembly illustrated in FIG. 1.
FIG. 2b is a top view of a head end of the casing assembly illustrated
in FIG. 1.
FIG. 2c is a bottom view of a tail end of the casing assembly illustrated
in FIG. 1.
FIG. 2d is a partial cross-sectional view of a retaining ring groove
of the casing assembly shown in FIG. 1.
FIG. 2e is a partial cross-sectional view of an o-ring groove in
a head end of the casing assembly shown in FIG. 1.
FIG. 2f is a partial cross-sectional view of another o-ring groove
in a head end of the casing assembly shown in FIG. 1.
FIG. 2g is a top view of a porous plate according to the present
invention.
FIG. 2h is a top view of a spring retaining plate according to
the present invention.
FIG. 3a is a perspective view of a twin tower air dryer system
featuring two desiccant element housings each of which featuring
the casing assembly of the present invention.
FIG. 3b is a cross-sectional view of a main portion of the desiccant
element housing illustrated in FIG. 3a.
DETAILED DESCRIPTION OF THE INVENTION
Before describing the present invention in detail, the reader is
advised that, for the sake of clarity and understanding, identical
components having identical functions in each of the accompanying
drawings have been marked where possible with the same reference
numerals in each of the Figures in this document.
FIGS. 1 through 3 illustrate the essential details of a casing
assembly of a desiccant element housing of an air dryer system.
The casing assembly, generally designated 100 is designed to house
a desiccant element 400 of the bag variety having the characteristics
shown in FIG. 1. The casing assembly 100 may be used in many types
of air dryer systems such as the one or two tower (i.e., desiccant
housing) systems alluded to in the background. FIG. 3 for example,
illustrates a twin tower system 300 featuring two desiccant element
housings 200a and 200b each of which embodying the casing assembly
100 of the present invention. The twin tower air dryer system 300
operates as indicated in one of the documents incorporated herein
by reference.
Referring to FIG. 1 the present invention provides a casing assembly
100 of a desiccant element housing for housing a desiccant element
400 in an air dryer system. In a presently preferred embodiment,
the casing assembly 100 includes a casing portion 101 a retaining
means 102 a head end porous plate 103 a tail end porous plate
104 and a means 105 for compacting the desiccant element 400.
The casing portion 101 is best illustrated in FIG. 2a. The casing
portion 101 has an inner sleeve 106 and an outer sleeve 107 with
a channel 108 defined between the sleeves. The sleeves preferably
connect to each other via a plurality of connecting tabs 138 as
best shown in FIGS. 1 and 2a. The channel 108 channels moisture-bearing
air from an inlet port 109 of a head end 110 of casing portion 101
out a tail end 111 of casing portion 101. The inner sleeve 106 defines
a flow chamber 112 extending from the tail end 111 to the head end
110. The head end 110 as illustrated in FIGS. 1 2a and 2b features
an inner seat face 113 that seals against an inner sealing flange
201 of a main portion 210 of desiccant housing 200. The inner sealing
flange 201 is shown in FIG. 3b. FIG. 3a illustrates two main portions
210a and 210b, one for each desiccant element housing 200a and 200b.
The head end 110 also features an outer seat face 114 that sealingly
connects to an outer sealing flange 203 of main portion 210 of desiccant
element housing 200. Given that inner and outer seat faces 113 and
114 of casing assembly 100 seal against inner and outer sealing
flanges 201 and 203 of main portion 200 of desiccant housing 200
this allows inlet port 109 to communicate with a supply port 230
of main portion 210 from which the moisture-bearing air is received
during a drying mode of operation of the air dryer system. It also
allows an outlet port 115 of head end 110 to communicate with a
delivery port 240 of main portion 200 out of which dried air is
directed during the drying mode.
The retaining means 102 affixes to inner sleeve 106 within flow
chamber 112 at the head end 110 of casing portion 101. The retaining
means 102 is a ring or like device that affixes within a groove
116 defined within inner sleeve 106 in the head end 110 as best
shown in FIGS. 2a and 2d. The head end porous plate 103 abuts an
interior facing side of retaining ring 102 within flow chamber 112
as illustrated in FIG. 1. The tail end porous plate 104 is slidably
disposed within flow chamber 112 near tail end 111.
The compacting means 105 is connected to an inner face 117 of tail
end 111 and abuts the tail end porous plate 104. It compacts the
desiccant element 400 within flow chamber 112 between the porous
plates 103 and 104. Whether used with a desiccant element in bag
form or even loose pelletized form, the compacting means 105 assures
that the desiccant is uniformly distributed within the flow chamber
112. Compressed by the compacting means 105 the desiccant tends
fill all available space between the porous plates 103 and 104
as the desiccant is even forced outwardly against the walls of inner
sleeve 106.
The compacting means 105 includes a spring retaining plate 118
as shown in FIGS. 1 and 2h and a spring 119 as shown FIG. 1. The
spring retaining plate 118 affixes via a plurality of screws or
bolts 120 to the inner face 117 of tail end 111 as illustrated
in FIGS. 1 and 2h. The spring 119 is situated between spring retaining
plate 118 and tail end porous plate 104 so as to maintain a compressive
force upon desiccant element 400 disposed in flow chamber 112 between
porous plates 103 and 104.
The porous plates 103 and 104 are of the type shown in FIG. 2g.
Each plate has a plurality of apertures that allow flow of air while
trapping any loose desiccant as well other airborne particulates
whose dimensions exceed the size of the apertures.
The tail end 111 as shown in FIGS. 1 and 2c also features an outer
seat face 121 that sealingly connects to a sealing flange 522 of
a cover portion 500 of desiccant housing 200. The cover portion
500 redirects the moisture-bearing air that is channeled out of
tail end 111. Specifically, the cover portion 500 redirects the
flow of moisturized air received from channel 108 into the flow
chamber 112 where it is dried by desiccant element 400 during the
drying mode of operation of air dryer system.
The casing assembly 100 connects at its head end 110 to the main
portion 210 via a plurality of bolts or screws, as shown in FIGS.
1 and 3b. Specifically, the outer seat face 114 of head end 110
connects via bolts to the outer sealing flange 203 of main portion
210 of desiccant housing 200. Likewise, the casing assembly 100
connects at its tail end 111 to cover portion 500 via a plurality
of bolts or screws, as shown in FIGS. 1 and 2c. Specifically, the
outer seat face 121 of tail end 111 connects via bolts to sealing
flange 522 of cover portion 500. When connected in this manner,
the main portion 210 casing assembly 100 and cover portion 500
together form desiccant housing 200. FIG. 3a, for example, illustrates
two desiccant housings 200a and 200b in the twin tower air dryer
system 300. Each desiccant housings 200a and 220b has a main portion
(e.g., 210a/ 210b), a casing assembly (e.g., 100a/ 100b) and a cover
portion (e.g., 500a/ 500b).
The three portions of the desiccant housing when connected to each
other seal against each other via o-rings. Specifically, the casing
assembly 100 seals against the main portion 210 via two O-rings.
The inner seat face 113 of head end 110 defines a groove 122 into
which one o-ring retains. The outer seat face 114 of head end 100
defines a groove 123 into which the other o-ring retains. These
two grooves are best shown in FIGS. 2a, 2e and 2f. These two seals
serve to isolate inlet port 109 and outlet port 115 from each other
and from atmosphere. Likewise, the cover portion 500 seals against
casing assembly 100 via a third o-ring. The sealing flange 522 of
cover portion 500 defines a groove 523 into which this third o-ring
retains. It is this seal that allows casing assembly 100 to seal
against cover portion 500.
The cover portion 500 may take any one of a variety of shapes,
though preferably the shape illustrated in FIG. 1. The cover portion
500 includes a cover body 501. The cover body 501 features the sealing
flange 522 whose surface is designed to seal against and connect
to outer seat face 121 of casing portion 101.
The cover body 501 defines a focal chamber 502 and a purge port
250 such that focal chamber 502 extends from sealing flange 522
to purge port 250. The shape of focal chamber 502 is configured
so that the moisture-bearing air received from channel 108 of casing
portion 101 is efficiently redirected into flow chamber 112 of casing
portion 101 during a drying mode of operation of an air dryer system.
The shape of focal chamber 502 is also configured so that the remoisturized
air received from flow chamber 112 is directed to purge port 250
for expulsion to atmosphere during a purge mode of operation of
the air dryer system. The documents incorporated herein by reference
describe the operation of air dryer systems in general and in doing
so explain the significance of the drying and purging modes of operation.
The modes of operation, of course, are well known in the air drying
art.
The desiccant element 400 illustrated in FIG. 1 preferably takes
the form of a bag of desiccant so as to take full advantage of the
present invention 100. Specifically, should loose desiccant pellets
be used instead of bag desiccant, replacement of the desiccant would
require removal of casing assembly 100 from the main portion 210
of desiccant housing 200. After the casing assembly 100 is removed
then one would have to remove the compacting means 105 so as to
dispose of the loose desiccant in an orderly fashion. The casing
assembly 100 would then have to be reconnected to the main portion
210. Such reconnection necessarily involves making sure that the
head end 110 of the casing assembly 100 is properly seated within
main portion 210.
Replacement of a bag of desiccant, by contrast, would merely require
removal of the cover portion 500 and the compacting means 105. One
would need only to pull out the old bag desiccant and insert the
new bag desiccant then reconnect the compacting means 105 and the
cover portion 500. Because the casing assembly 100 need not be removed
from main portion 100 there is no need for realignment of the head
end 110 of casing assembly 100 within the main portion 210 of the
desiccant housing 200. Such laborious realignment and connection
is typical of prior art desiccant housings. Compared to prior art
housings, the present invention allows easy access to and removal
of the desiccant element 400.
Notwithstanding the preference that the present invention be used
with bag desiccant, the casing assembly 100 may be used with loose
pelletized desiccant such as a mesh white activated alumina desiccant.
Should loose desiccant be used, one must, of course, use a pellet
size whose diameter is larger than the diameter of the apertures
of the porous plates 103 and 104.
While the presently preferred embodiment and related aspects have
been set forth in detail according to the Patent Act, those persons
of ordinary skill in the technical art to which this invention pertains
will recognize various alternative ways of practicing the invention
without departing from the spirit and scope of the appended claims.
Those of ordinary skill will also recognize that the foregoing description
is merely illustrative and is not intended to limit any of the following
claims to any particular narrow interpretation.
Accordingly, to promote the progress of science and useful arts,
I secure for myself by Letters Patent exclusive rights to all subject
matter embraced by the following claims for the time prescribed
by the Patent Act. |