Abstrict A gas drying canister housing for a desiccant canister in a gas
dryer system includes a main portion having an upper base and a
lower portion having a lower base. A canister bore is defined between
the upper and lower bases when the main and lower portions are fastened
to each other. The main portion defines a supply port through which
a stream of moisture-bearing gas is directed into the housing for
passage through the desiccant canister during a drying mode of operation
of the gas dryer system. The main portion also defines a delivery
port through which a stream of dried gas is directed from the housing
during the drying mode. The lower portion defines a purge port through
the lower base through which a stream of remoisturized gas is expelled
from the housing during a purge mode of operation of the gas dryer
system. The upper base of the main portion features a sealing flange
against which an outer rim portion of a top of the desiccant canister
is seatable so as to make an air tight seal therebetween. The gas
drying canister housing further includes a mechanism for aligning
and securably retaining the desiccant canister within the housing
such that when the desiccant canister is so aligned and securably
retained the top of the desiccant canister aligns with and seals
against the sealing flange and communication between the supply
and delivery ports of the housing is possible only through the desiccant
canister.
Claims I claim:
1. A gas drying assembly housing for a desiccant canister assembly
of a gas dryer system, said gas drying assembly housing comprising:
(a) a main portion defining (i) a main bore extending from an upper
base of said main portion, (ii) a supply port through which a stream
of moisture-bearing gas is directed into said gas drying assembly
housing for passage through said desiccant canister assembly during
a drying mode of operation of said gas dryer system and (iii) a
delivery port through which a stream of dried gas is directed from
said gas drying assembly housing during said drying mode;
(b) a sealing flange on said upper base of said main portion against
which an outer ring portion of a top of said desiccant canister
assembly is seatable so as to make an air tight seal therebetween;
(c) a means for aligning and securably retaining said desiccant
canister assembly within said main bore of said main portion such
that when said desiccant canister assembly is so aligned and securably
retained said top of said desiccant canister assembly aligns with
and seals against said sealing flange of said main portion and communication
between said supply and delivery ports via said housing is possible
only through said desiccant canister assembly; and
(d) a lower portion defining (i) a lower bore extending from a
lower base of said lower portion and (ii) a purge port through said
lower base through which a stream of remoisturized gas is expelled
from said gas drying assembly housing during a purge mode of operation
of said gas dryer system; said main portion and said lower portion
are fastenable to each other so as to form said gas drying assembly
housing for said desiccant canister assembly.
2. The gas drying assembly housing as recited in claim 1 wherein
said means for aligning and securably retaining includes a threaded
rod extending from a center of said upper base of said housing into
said lower portion, said threaded rod for inserting through a positioning
bore defined through a center of said desiccant canister assembly
so as to retain said desiccant canister assembly about said threaded
rod via a securing means so that said top of said desiccant canister
assembly aligns with and seals against said sealing flange of said
housing.
3. The gas drying assembly housing as recited in claim 2 wherein
said securing means includes a lock washer and a stop nut threaded
onto said threaded rod.
4. A gas drying canister housing in a gas dryer system for a desiccant
canister assembly, said gas drying canister housing comprising:
(a) a main portion having an upper base and a lower portion having
a lower base with a canister bore defined between said upper and
said lower bases when said main and said lower portions are fastened
to each other, said main portion defining (i) a supply port through
which a stream of moisture-bearing gas is directed into said housing
for passage through said desiccant canister assembly during a drying
mode of operation of said gas dryer system and (ii) a delivery port
through which a stream of dried gas is directed from said housing
during said drying mode, said lower portion defining a purge port
through said lower base through which a stream of remoisturized
gas is expelled from said housing during a purge mode of operation
of said gas dryer system;
(b) a sealing flange on said upper base against which an outer
rim portion of a top of said desiccant canister assembly is seatable
so as to make an air tight seal therebetween; and
(c) a means for aligning and securably retaining said desiccant
canister assembly within said housing such that when said desiccant
canister assembly is so aligned and securably retained said top
of said desiccant canister assembly aligns with and seals against
said sealing flange of said main portion and communication between
said supply and delivery ports via said housing is possible only
through said desiccant canister assembly.
5. The gas drying canister housing as recited in claim 4 wherein
said means for aligning and securably retaining includes a threaded
rod extending from a center of said upper base of said main portion
into said lower portion, said threaded rod for inserting through
a positioning bore defined through a center of said desiccant canister
assembly so as to retain said desiccant canister assembly about
said threaded rod via a securing means so that said top of said
desiccant canister assembly aligns with and seals against said sealing
flange of said housing.
6. The gas drying canister housing as recited in claim 5 wherein
said securing means includes a lock washer and a stop nut threaded
onto said threaded rod.
7. A regenerative gas dryer system for cleaning and drying a stream
of unpurified pressurized gas received from a source thereof for
use by a pneumatic system, said regenerative gas dryer system comprising:
(a) an inlet manifold defining a supply passage for receiving said
stream of unpurified gas from said source, a first delivery passage
and a second delivery passage;
(b) a coalescing filter chamber for initially separating moisture
and other particulates from said stream of unpurified gas received
from said supply passage of said inlet manifold so as to deliver
a stream of initially filtered gas to said delivery passages of
said inlet manifold;
(c) a first desiccant canister housing having a desiccant canister
therein for removing moisture remaining within said stream of initially
filtered gas received from said first delivery passage of said inlet
manifold so as to supply a first stream of purified gas;
(d) a second desiccant canister housing having a desiccant canister
therein for removing moisture remaining within said stream of initially
filtered gas received from said second delivery passage of said
inlet manifold so as to supply a second stream of purified gas;
(e) an inlet check valve means for affecting flow from said first
and said second delivery passages of said inlet manifold to said
first and said second housings, respectively;
(f) an outlet manifold defining a first supply passage for receiving
said first stream of purified gas from said first housing, a second
supply passage for receiving said second stream of purified gas
from said second housing and a delivery passage for delivering said
first and said second streams of purified gas to said pneumatic
system;
(g) an outlet check valve means for affecting flow from said first
and second supply passages of said outlet manifold to said delivery
passage of said outlet manifold;
(h) a purge valve means through which moisture previously collected
in said first and said second housings is expelled to atmosphere;
each of said housings featuring:
(i) a main portion having an upper base and a lower portion having
a lower base with a canister bore defined between said bases when
said portions are fastened to each other, said main portion defining
(I) a supply port through which said stream of initially filtered
gas from said inlet valve means is directed into said housing for
passage through said desiccant canister and (II) a delivery port
through which said stream of purified gas is directed from said
housing;
(ii) a sealing flange on said upper base against which an outer
ring portion of a top of said desiccant canister is seatable so
as to make an air tight seal therebetween; and
(iii) a means for aligning and securably retaining said desiccant
canister within said housing such that when said desiccant canister
is so aligned and securably retained said top of said desiccant
canister aligns with and seals against said sealing flange of said
main portion and communication between said supply and delivery
ports of said housing is possible only through said desiccant canister;
and
(i) a controlling means for coordinating operation of all of said
valve means according to a preset cycle thereby switching operation
of said gas dryer system alternately between (I) a first half of
said preset cycle during which moisture is extracted from said stream
of initially filtered gas received from said first delivery passage
of said inlet manifold that passes through said inlet check valve
means into said supply port of said first housing and out said delivery
port thereof from which flows said first stream of purified gas
to a choke valve means that directs said first stream of purified
gas in an output percentage to said pneumatic system and in a purge
percentage to and through said second housing and out said purge
valve means to atmosphere thereby purging said second housing of
previously collected moisture and (II) a second half of said preset
cycle during which moisture is extracted from said stream of initially
filtered gas received from said second delivery passage of said
inlet manifold that passes through said inlet check valve means
into said supply port of said second housing and out said delivery
port thereof from which flows said second stream of purified gas
to said choke valve means that directs said second stream of purified
gas in said output percentage to said pneumatic system and in said
purge percentage to and through said first housing and out said
purge valve means to atmosphere thereby purging said first housing
of previously collected moisture.
8. The regenerative gas dryer system recited in claim 7 wherein
said coalescing chamber includes a drain valve means controlled
by said controlling means such that said drain valve means opens
briefly as said gas dryer system switches between said first and
said second halves of said preset cycle thereby permitting moisture
previously collected in said coalescing chamber to be expelled to
atmosphere.
9. The regenerative gas dryer system recited in claim 8 further
including a pressure sensing means connected to said controlling
means for sensing pressure within said gas dryer system such that
when said sensed pressure falls below a predetermined level all
of said valves means assume their respective normal states and when
said sensed pressure reaches or exceeds said predetermined level
said gas dryer system operates according to said preset cycle.
10. The gas drying canister housing as recited in claim 9 wherein
said controlling means includes a memory circuit for remembering
a time within said preset cycle when said source of pressurized
gas becomes unloaded such that when said source again becomes loaded
and said sensed pressure within said gas dryer system remains equals
to or exceeds said predetermined level, said controlling means resumes
operation of said gas dryer system at said time within said preset
cycle.
11. The regenerative gas dryer system recited in claim 9 wherein
said controlling means continues operating said gas dryer system
according to said preset cycle as long as said sensed pressure within
said gas dryer system equals or exceeds said predetermined level
and said source of pressurized gas remains loaded.
12. The regenerative gas dryer system recited in claim 8 wherein
said inlet check valve means includes:
(a) a first normally open inlet check valve affect flow between
said first delivery passage of said inlet manifold and said supply
port of said first desiccant canister housing; and
(b) a second normally open inlet check valve affects flow between
said second delivery passage of said inlet manifold and said supply
port of said second desiccant canister housing.
13. The regenerative gas dryer system recited in claim 12 wherein
said outlet check valve means includes:
(a) a first normally open outlet check valve affects flow between
said first supply passage of said outlet manifold and said delivery
passage of said outlet manifold; and
(b) a second normally open outlet check valve affects flow between
said second supply passage of said outlet manifold and said delivery
passage of said outlet manifold.
14. The regenerative gas dryer system recited in claim 13 wherein
said purge valve means includes:
(a) a first normally closed purge valve connected to a purge port
defined by said lower base of said first desiccant canister assembly;
and
(b) a second normally closed purge valve connected to a purge port
defined by said lower base of said second desiccant canister assembly.
15. The regenerative gas dryer system recited in claim 14 wherein
said drain valve means is a normally closed double seated drain
valve.
16. The regenerative gas dryer system recited in claim 15 wherein
said controlling means controls the opening and closing of said
valves according to said preset cycle such that:
(a) during said first half of said preset cycle, said first inlet
check valve and said first outlet check valve are open and said
first purge valve is closed while said second inlet check valve
and said second outlet check valve are closed and said second purge
valve is open; and
(b) during said second half of said preset cycle, said second inlet
check valve and said second outlet check valve are open and said
second purge valve is closed while said first inlet check valve
and said first outlet check valve are closed and said first purge
valve is open.
17. The regenerative gas dryer system recited in claim 16 wherein
said valves are air piloted valves.
18. The regenerative gas dryer system recited in claim 17 wherein
said controlling means includes:
(a) a first normally closed three way solenoid valve for controlling
supply of pilot air to said first inlet check valve, said first
outlet check valve, said first purge valve and said drain valve;
(b) a second normally closed three way solenoid valve for controlling
supply of pilot air to said second inlet check valve, said second
outlet check valve, said second purge valve and said drain valve;
and
(c) an electronic controller for controlling operation of said
first and said second solenoid valves according to said preset cycle.
19. The regenerative gas dryer system recited in claim 7 wherein
for each of said housings said means for aligning and securably
retaining includes a threaded rod extending from a center of said
upper base of said main portion into said lower portion, said threaded
rod for inserting through a positioning bore defined through a center
of said desiccant canister so as to retain said desiccant canister
about said threaded rod via a securing means so that said top of
said desiccant canister aligns with and seals against said sealing
flange of said housing.
Description CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to copending applications Ser. Nos.
08/713471 and 08/710209 entitled Desiccant Canister With Positioning
Bore and Molded Rubber Valve Seal For Use In Predetermined Type
Valves Such As A Check Valve In A Regenerative Air Dryer, respectively,
both sharing the same filing date of the present application, Sep.
13 1996. 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 present invention relates to a regenerative
air dryer system which alternately switches between removing moisture
from air to be used by the pneumatic system by passing it through
a first drying assembly while purging previously collected moisture
from a second drying assembly and removing moisture from air to
be used by the pneumatic system by passing it through the second
drying assembly while purging previously collected moisture from
the first drying assembly. Still more particularly, the present
invention pertains to a desiccant canister assembly housing which
features a mechanism for aligning and securably retaining a desiccant
canister within the desiccant canister assembly housing of an air
dryer system.
BACKGROUND OF THE INVENTION
It is well known that air dryer systems are designed to remove
moisture vapor from a stream of compressed air into which the air
dryer system is incorporated. In practice, an air dryer system employs
one or more standard air drying assemblies each of which contains
a moisture absorbing material to absorb the moisture from the air.
In air dryer systems having one air drying assembly, the air drying
assembly through its moisture absorbing material 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 moisture
absorbing material to draw out the absorbed moisture. The stream
of compressed air with the revaporized moisture it carries is then
discharged to the atmosphere thereby regenerating the moisture absorbing
material contained in the air drying assembly.
In air dryer systems having two air drying assemblies, the air
drying system alternately cycles between removing moisture from
air passing through a first drying assembly while purging from a
second drying assembly moisture previously collected therein and
removing moisture from air passing through the second drying assembly
while purging from the first drying assembly moisture previously
collected therein.
Prior to the present invention, such prior art air dryer systems
generally have used the standard air drying assembly to perform
the air drying function. Whether the air dryer system employs one
or more standard air drying assemblies, each standard air drying
assembly inserts into a housing designed to hold same. The prior
art housings, however, generally retain the standard air drying
assembly through a tight press fitting, or in other terms, interference
fitting of the assembly within the housing. Specifically, the fit
of the standard air drying assembly into its corresponding housing
in the air dryer system is so tight that it typically must be hammered
into the housing with a mallet or like instrument.
The standard air drying assembly and corresponding housing design
thus present a number of shortcomings. First, the process of installing
the standard air drying assembly into the housing is quite strenuous
and takes too much time. Second, one can not be sure whether the
standard air drying assembly is properly aligned within the housing
so that the top of the assembly seats against and makes an air tight
seal with a sealing face of the housing. Third, removal of the standard
air drying assembly from the housing is often quite difficult because
of its tight fit within the housing. For these reasons, a regenerative
air dryer system inclusive of a novel air drying assembly housing
that does not exhibit the disadvantages outlined above is described
and claimed herein as follows.
The present regenerative air dryer system can be applied to a wide
variety of pneumatic systems. Typical of the types of pneumatic
systems to which the instant 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 system 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 instant invention.
Accordingly, any terms of art used herein are not intended to be
limited to any particular narrow interpretation unless specifically
stated otherwise in this document.
SUMMARY OF THE INVENTION
In a presently preferred embodiment, the present invention provides
an air drying canister housing for a desiccant canister in an air
dryer system. The canister housing includes a main portion having
an upper base and a lower portion having a lower base. A canister
bore is defined between the upper and lower bases when the main
and lower portions are fastened to each other. The main portion
defines a supply port through which a stream of moisture-bearing
air is directed into the housing for passage through the desiccant
canister during a drying mode of operation. The main portion also
defines a delivery port through which a stream of dried air is directed
from the housing during the drying mode. The lower portion defines
a purge port through the lower base through which a stream of remoisturized
air is expelled from the housing during a purge mode of operation
of the air dryer system. The upper base of the main portion features
a sealing flange against which an outer rim portion of a top of
the desiccant canister is seatable so as to make an air tight seal
therebetween. The air drying canister housing further includes a
mechanism for aligning and securably retaining the desiccant canister
within the housing such that when the desiccant canister is so aligned
and securably retained the top of the desiccant canister aligns
with and seals against the sealing flange and communication between
the supply and delivery ports of the housing is possible only through
the desiccant canister.
OBJECTS OF THE INVENTION
It is, therefore, one of the primary objects of the present invention
to provide a novel desiccant canister housing assembly for an air
dryer system.
Another object of the present invention is to provide a novel housing
assembly for a desiccant canister within an air dryer system wherein
the housing assembly includes a mechanism for aligning and securably
retaining the desiccant canister within the housing assembly.
Yet another object of the present invention is to provide a novel
housing assembly for a desiccant canister within an air dryer system
wherein the housing assembly features a threaded rod extending from
a center of an upper base of the housing assembly for insertion
through a positioning bore defined through a center of the desiccant
canister so as to securably retain the desiccant canister about
the threaded rod with a securing means so that a top of the desiccant
canister aligns with and seals against a sealing flange of the housing
assembly.
Still another object of the present invention is to provide a novel
housing assembly for a desiccant canister within an air dryer system
wherein the desiccant canister easily installs into and removes
from the housing assembly as compared to prior art housing assemblies
and their corresponding desiccant canisters.
A further object of the present invention is to provide a regenerative
air dryer system inclusive of at least one novel housing assembly
wherein a desiccant canister easily installs into and removes from
the housing assembly as compared to prior art housing assemblies
and their corresponding desiccant canisters.
In addition to the objects and advantages of the present invention
set forth above, various other objects 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.
Such other objects and advantages will become particularly apparent
when the detailed description is considered in conjunction with
the attached drawings and with the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a desiccant canister housing
assembly according to the present invention.
FIG. 2 is a cross-sectional view of the desiccant canister housing
assembly of FIG. 1 into which a corresponding desiccant canister
has been aligned and securably retained.
FIG. 3 is a perspective view of a regenerative air dryer system
showing two desiccant canister housing assemblies of the type illustrated
in FIGS. 1 and 2.
DETAILED DESCRIPTION OF THE INVENTION
Before describing the present invention in detail, for the sake
of clarity and understanding, the reader is advised that identical
components having identical functions in each of the accompanying
drawings have been marked with the same reference numerals throughout
each of the several Figures illustrated herein.
FIGS. 1 and 2 illustrate the essential details of a desiccant canister
housing assembly of an air dryer system. The desiccant canister
housing assembly may be used to house any one of a variety of desiccant
canisters having the basic structural characteristics shown in FIG.
2. FIG. 3 shows a regenerative air dryer system that has two of
the desiccant canister housing assemblies shown in FIG. 1. It is
a desiccant canister having the basic structural characteristics
shown in FIG. 2 that the canister housing assembly of the present
invention is primarily designed to retain. One such desiccant canister
is featured in one of the aforementioned documents previously incorporated
herein by reference.
In a presently preferred embodiment, the desiccant canister housing
assembly, generally designated 200 includes a main portion 210
and a lower portion 220. Main portion 210 has an upper base 202
and lower portion 220 has a lower base 222. A main bore extends
from upper base 202 of main portion 210 and a lower bore extends
from lower base 222 of lower portion 220. A canister bore 215 is
defined between the upper and lower bases when main portion 210
is fastened to lower portion 220. It is within this canister bore
215 that the aforementioned desiccant canister 100 is to be housed
as shown in FIG. 2.
Referring to FIGS. 1 and 2 main portion 210 defines a supply port,
generally designated 230 through which a stream of moisture-bearing
air is directed into housing assembly 200 for passage through the
desiccant canister 100 to remove the moisture from the incoming
stream of air. The moisture is absorbed by the desiccant canister
housed within housing assembly 200 when housing assembly 200 is
operated in a drying mode of operation by the air dryer system as
is well known in the technical field pertaining to air drying. Main
portion 210 also defines a delivery port, generally designated 240
through which a stream of dried air is directed from housing assembly
200 during the drying mode. Lower portion 220 defines a purge port
250 through its lower base 222 through which a stream of remoisturized
gas is expelled from housing assembly 200. The moisture is expelled
from housing assembly 200 when housing assembly 200 is operated
in a purge mode of operation by the air dryer system as is well
known in the air drying art.
Main portion 210 on its upper base 202 also features a sealing
flange 201 as shown in FIGS. 1 and 2. As explained further below,
sealing flange 201 is the seat which a corresponding top of the
desiccant canister 100 aligns with and preferably seals against
so as to make an air tight seal between the desiccant canister 100
and housing assembly 200.
The desiccant canister housing assembly 200 also includes a means,
generally designated 260 for aligning and securably retaining the
desiccant canister within canister bore 215. As shown in FIGS. 1
and 2 the means for aligning and securably retaining 260 includes
a threaded rod 203 extending from a center of upper base 202 into
lower portion 220. The threaded rod 203 is for inserting through
a positioning bore defined through a center of the desiccant canister
100. The desiccant canister 100 securably retains about threaded
rod 203 via a securing means 204 such as a lock washer 205 and a
stop nut 206 as best shown in FIG. 2. Through securing means 204
the means for aligning and retaining 260 retains the desiccant canister
100 so that the top of the desiccant canister 100 aligns with and
seals against sealing flange 201 of main portion 210.
The sealing flange 201 is preferably designed to seal against a
desiccant canister that has an outer ring portion at its top. As
shown in FIG. 2 the outer ring portion 110 preferably includes
a groove 111 within which an o-ring 112 retains. Through o-ring
112 the outer ring portion 110 seats against and makes an air tight
seal with sealing flange 201. It is through this means for aligning
and securably retaining 260 that sealing flange 201 of canister
housing assembly 200 aligns with and seals against the top of the
desiccant canister 100. When the desiccant canister 100 and sealing
flange 201 are seated against one another, communication between
supply port 230 and delivery port 240 is possible only through the
desiccant canister 100 as is best shown in FIG. 2.
Referring now to FIG. 4 a regenerative air dryer system, generally
designated 300 includes two desiccant canister housing assemblies
200a and 200b of the type illustrated in FIGS. 1 and 2. The regenerative
air dryer system 300 installs within a pneumatic system to clean
and dry a stream of unpurified air received from source of pressurized
air. The air dryer system 300 includes an inlet manifold 310 a
coalescing filter chamber 320 a first desiccant canister housing
assembly 200a, a second canister assembly housing 200b, an inlet
check valve means 330 an outlet manifold 340 an outlet check valve
means 350 a purge valve means 360 and controlling means 370.
The inlet manifold 310 defines a supply passage 311 for receiving
the stream of unpurified air from the source of pressurized air
(not shown). The inlet manifold 310 also defines first and second
delivery passages, generally designated 312a and 312b, respectively.
Similarly, the outlet manifold 340 defines a first supply passage
and a second supply passage, generally designated 341a and 341b,
respectively. Supply passage 341a connects to delivery port 240a
of first housing assembly 200a as best shown in FIGS. 1 and 3. Similarly,
supply passage 341b connects to delivery port 240b of second housing
assembly 200b. The outlet manifold 340 also defines a delivery passage
342 through which a stream of cleaned and dried air is delivered
to the pneumatic system (not shown).
The coalescing filter chamber 320 initially separates moisture
and other particulates from the stream of unpurified air received
from supply passage 311 of inlet manifold 310 and delivers a stream
of initially filtered air to the delivery passages 312a and 312b
of inlet manifold 310. The filter contained within the coalescing
chamber 310 is preferably a borosilicate filter.
The inlet check valve means 330 affects flow from first 312a and
second 312b delivery passages of inlet manifold 310 to first 200a
and second 200b housing assemblies, respectively. The inlet check
valve means 330 includes first and second normally open inlet check
valves 330a and 330b. First inlet check valve 330a affects flow
between first delivery passage 312a of inlet manifold 310 and supply
port 230a of first housing assembly 200a as is best shown in FIGS.
1 and 3. Similarly, second inlet check valve 330b affects flow between
second delivery passage 312b of inlet manifold 310 and supply port
230b of second housing assembly 200b.
The outlet check valve means 350 affects flow from first 341a and
second 341b supply passages of outlet manifold 340 to delivery passage
342 of outlet manifold 340. The outlet check valve means 350 includes
first and second normally open outlet check valves 350a and 350b.
First outlet check valve 350a affects flow between first supply
passage 341a of outlet manifold 340 and delivery passage 342 of
outlet manifold 340. Similarly, second outlet check valve 350b affects
flow between second supply passage 341b of outlet manifold 340 and
delivery passage 342 of outlet manifold 340.
The purge valve means 360 is a device through which moisture previously
collected in first 200a and second 200b housing assemblies is expelled
to atmosphere. The purge valve means includes first and second normally
closed purge valves 360a and 360b. First purge valve 360a connects
to purge port 250a defined through the lower base of first housing
assembly 200a as is best shown in FIGS. 1 and 3. Similarly, second
purge valve 360b connects to purge port 250b defined through the
lower base of second housing assembly 200b. The regenerative gas
dryer system 300 also provides a drain valve means, generally designated
380. The drain valve means 380 includes a normally closed double
seated drain valve 381 at the bottom of coalescing filter chamber
320.
The controlling means 370 generally coordinates operation of all
of the valve means of the air dryer system 300 according to a preset
operating cycle. During a first half of the preset cycle, the valves
of the air dryer system 300 are set so that first desiccant canister
housing 200a removes moisture from the stream of initially filtered
air while second desiccant canister housing 200b is purged of moisture
it has previously collected. Specifically, first inlet check valve
330a and first outlet check valve 350a are open and first purge
valve 360a is closed while second inlet check valve 330b and second
outlet check valve 350b are closed and second purge valve 360b is
open. The regenerative air dryer system 300 then generally operates
as follows. The stream of initially filtered air flows from coalescing
chamber 320 into first 312a and second 312b delivery passages of
inlet manifold 310. Because first and second inlet valves 330a and
330b are open and closed, respectively, the stream of initially
filtered air flows only into first housing assembly 200a through
its supply port 230a as shown in FIGS. 1 and 3. First desiccant
housing 200a extracts moisture from the stream of initially filtered
air. From first housing assembly 200a flows a first stream of purified
air to a choke valve means, generally designated 390 located between
main portions 210a and 210b. Choke valve means 390 directs the first
stream of purified air in an output percentage to the pneumatic
system and in a purge percentage to second housing assembly 200b.
The purge percentage of the first stream of purified air flows through
second housing assembly 200b thereby reabsorbing the moisture previously
contained within its desiccant canister. This remoisturized air
stream then flows through purge port 250b and purge valve 360b to
atmosphere thereby regenerating second housing assembly 200b for
a second half of the preset cycle. Meanwhile, the output percentage
of the first stream of purified air flows through delivery port
240a of first housing assembly 200a into first supply port 341a
of outlet manifold 340. Because first outlet check valve 350a is
open, the output percentage of the first stream of purified air
flows through first supply 341a and delivery 342 passages of outlet
manifold 340 into the pneumatic system.
During the second half of the preset cycle, the valves of the air
dryer system 300 are set so that second desiccant canister housing
200b removes moisture from the stream of initially filtered air
while first desiccant canister housing 200a is purged of moisture
it has previously collected. Specifically, second inlet check valve
330b and second outlet check valve 350b are open and second purge
valve 360b is closed while first inlet check valve 330a and first
outlet check valve 350a are closed and first purge valve 360a is
open. The regenerative air dryer system 300 then generally operates
as follows. The stream of initially filtered air flows from coalescing
chamber 320 into first 312a and second 312b delivery passages of
inlet manifold 310. Because first and second inlet valves 330a and
330b are closed and open, respectively, the stream of initially
filtered air flows only into second housing assembly 200b through
its supply port 230b as shown in FIGS. 1 and 3. Second desiccant
housing 200b extracts moisture from the stream of initially filtered
air. From second housing assembly 200b flows a second stream of
purified air to choke valve means 390 located between main portions
210a and 210b. Choke valve means 390 directs the second stream of
purified air in an output percentage to the pneumatic system and
in a purge percentage to first housing assembly 200a. The purge
percentage of the second stream of purified air flows through first
housing assembly 200a thereby reabsorbing the moisture previously
contained within its desiccant canister. This remoisturized air
stream then flows through purge port 250a and purge valve 360a to
atmosphere thereby regenerating first housing assembly 200a for
the first half of the preset cycle. Meanwhile, the output percentage
of the second stream of purified air flows through delivery port
240b of second housing assembly 200b into second supply port 341b
of outlet manifold 340. Because second outlet check valve 350b is
open, the output percentage of the second stream of purified air
flows through second supply 341b and delivery 342 passages of outlet
manifold 310 into the pneumatic system.
The controlling means 370 thus controls the operation of all the
valve means so that the air dryer system 300 alternates between
the first and second halves of the preset operating cycle. Preferably,
the preset operating cycle lasts two minutes with one minute allocated
for each half cycle. The controlling means 370 also controls drain
valve 381 situated at the bottom of coalescing filter chamber 320
so that drain valve 381 opens briefly as the air dryer system 300
switches between the first and second halves of the preset cycle.
This permits moisture previously collected in coalescing chamber
320 to be expelled to atmosphere.
The controlling means 370 includes a first actuating device, a
second actuating device and an electronic controller for controlling
operation of the actuating devices. The first actuating device controls
operation of first inlet check valve 330a, first outlet check valve
350a, first purge valve 360a and drain valve 381. The second actuating
device controls operation of second inlet check valve 330b, second
outlet check valve 350b, second purge valve 360b and drain valve
381. In the presently preferred embodiment of the air dryer system,
it is preferred that each of the valves be of the air piloted variety.
Consequently, first actuating device is preferably a normally closed
three way solenoid valve for controlling supply of pilot air to
the valves under its control. Likewise, second actuating device
is preferably a normally closed three way solenoid valve for controlling
supply of pilot air to the valves under its control. The electronic
controller includes within its electronic circuitry a timer circuit
through which to control the switching between the first and second
halves of the preset operating cycle.
The regenerative gas dryer system 300 further includes a pressure
sensor for sensing the pressure within the air dryer system 300.
When the pressure falls below a predetermined level, the controlling
means 370 allows all the valves to assume their respective normally
open or closed states. This will allow the maximum amount of air
to pass through the air dryer system 300 thereby reducing the time
required to charge the pneumatic system in which the air dryer system
300 is incorporated. Conversely, when the pressure reaches or exceeds
the predetermined level, the controlling means 370 operates the
air dryer system 300 according to the preset operating cycle. The
controlling means 370 will generally not operate the air dryer system
300 according to the preset operating cycle unless the pressure
is generally equal to or exceeds the predetermined level and the
source of compressed air is loaded.
The controlling means 370 also includes a memory circuit. When
the source of compressed air is loaded, the controlling means 370
receives a signal that activates the memory circuit. Through the
memory circuit, equal drying and purging times can be assured for
each of the first and second housing assemblies 200a and 200b. Specifically,
the memory circuit remembers the point within the preset operating
cycle when the source of compressed air becomes unloaded. The next
time that the source becomes loaded, the signal commences and the
air dryer system 300 resumes operation at the point in the preset
operating cycle at which it last operated.
The controlling means 370 also includes a power shut off feature.
When the supply of power to the controlling means 370 is cut off,
the controlling means 370 will start at the beginning of the preset
operating cycle when power is restored. This permits both the first
and second desiccant canister housing assemblies 200a and 200b to
perform a complete cycle upon start-up.
While the presently preferred embodiments of the canister housing
assembly invention and the air dryer system incorporating same 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 in the relevant art 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. |