Abstrict A canister assembly for containing a particulate desiccant in a
housing of a compressed gas filter assembly having for the feed
end of a canister a resiliently compressible closure formed of normally
spring-spaced inner and outer parts connected for limited relative
axial movement, the closure in operative position being contained
and releasably locked in the canister with its inner part yieldably
engaging an adjoining end of a charge of particulate desiccant.
Claims Having now described my invention, I claim:
1. A canister assembly for containing particulate material, comprising
a canister loadable through a feed end thereof with a charge of
said material, and closure means releasably insertible as a whole
into said feed end after loading of said canister for engaging and
containing an adjoining end of said charge, said closure means including
a spring loaded compression plate sub-assembly with limited vertical
or axial movement, comprising an end plate inner part and an outer
part slidable vertically or axially in and insertable through the
feed end of said canister, and spring means normally spacing said
parts and resiliently compressible for applying a compacting force
to and accommodating variations in said charge.
2. A canister assembly according to claim 1 wherein said particulate
material is a particulate desiccant for selectively adsorbing in
a compressed gas filter assembly a contaminant from compressed gas
passed therethrough, the charge of said desiccant on loading into
the canister is contained therein between said feed end and an outlet
end thereof, and including foraminous means in said outlet end for
containing and passing filtered gas from an outlet end of said charge,
the closure means also being foraminous for passing compressed gas
from the feed end through the charge.
3. A filter assembly according to claim 2 wherein the outlet end
foraminous means and closure means are slidable longitudinally in
and limited in outward movement relative to the canister, and the
closure means is fully compressible by a superior force applied
thereto through the desiccant for transferring compaction of the
desiccant to said superior force.
4. A canister assembly according to claim 3 including means insertible
into the feed end of the canister outwardly of said outer part for
releasably locking the closure means in the canister.
5. A canister assembly according to claim 4 wherein the outer
part of the closure means is compartmented for housing scrubber
means for trapping oil from compressed gas passing therethrough.
6. A canister assembly according to claim 4 including means connecting
the inner and outer parts for limiting relative outward travel thereof,
and stop means on at least one of the parts and engageable with
the other part for limiting relative inward travel thereof.
Description BACKGROUND OF THE INVENTION
While particulate desiccants such as molecular sieves are widely
used in compressed gas filter assemblies for selectively adsorbing
a contaminant, such as moisture, entrained in the gas, if the desiccant
is not tightly compacted in the canister or other container in which
it is contained, the inter-abrasion of the desiccant particles produces
an abrasive dust which is carried off by the filtered product gas
to the detriment of air brakes or other devices operated by the
product gas. Fluid-actuated top or bottom-acting compactors, such
as disclosed in the filter assemblies of Lanier Frantz U.S. Pat.
No. 4029086 and my U.S. Pat. No. 4113451 by exerting a compacting
force on the desiccant, minimize dust formation by the desiccant
particles. Also, as opposed to the external compacting springs they
are designed to replace, the fluid-actuated compactors of the Frantz
patents not only automatically apply a substantially uniform force
over their compacting range but can readily release that force to
facilitate insertion and removal of the canister.
Necessarily limited in their automatic compacting action to a particulate
desiccant in a canister installed in a filter assembly, the disclosed
embodiments of the compactors of the Frantz patents cannot compensate
for any looseness of the desiccant charge before the canister is
installed and, given such looseness, the handling of a charged canister
before installation, particularly in the field, can cause the desiccant
particles to create dust. If, as in those patents, the canister
closure is rigid, avoidance of the initial looseness requires that
the canister be very carefully loaded to capacity and this in turn
renders it difficult to apply the closure. It is to a solution of
these problems that the present invention is particularly directed.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide an improved
desiccant canister assembly wherein a closure for a feed end of
a canister of the assembly is so constructed as to be readily applied
to the canister and, when applied, to compact the desiccant particles
despite variations over a predetermined range in the quantity of
the charge.
Another object of the invention is to provide for a compressed
gas filter assembly an improved desiccant canister assembly wherein
a charge of particulate desiccant is contained in a canister and
the feed end of the canister is closable by a resiliently compressible
closure adapted by compensating for variations in the desiccant
charge to facilitate application of the closure after the canister
is loaded and, when applied, to compact the desiccant.
A further object of the invention is to provide for a compressed
gas filter assembly having a pneumatic compactor for compacting
a particulate desiccant contained in a canister, an improved canister
assembly whereof the feed end of the canister is closable by a resiliently
compressible closure readily applied to a loaded canister and adapted
not only to compact the desiccant despite variations in the quantity
of the charge but to yield to the force applied by and transfer
compacting to the pneumatic compactor on activation thereof while
maintaining a compacting force on the desiccant in case of accidental
deactivation of the compactor.
An additional object of the invention is to provide an improved
desiccant canister assembly for containing in a canister a charge
of particulate desiccant, wherein a resiliently compressible closure
removably insertible into a feed end of the canister for applying
internally of the canister and against the desiccant a spring force
for compacting the desiccant, is fully compressible by an externally
applied superior force for transferring compaction of the desiccant
thereto.
Other objects and advantages of the invention will appear hereinafter
in the detailed description, be particularly pointed out in the
appended claims and be illustrated in the accompanying drawings,
in which:
FIGURE DESCRIPTION
FIG. 1 is a central vertical sectional view of a preferred embodiment
of the desiccant canister assembly of the present invention; and
FIG. 2 is a horizontal sectional view taken along lines 2--2 of
FIG. 1.
DETAILED DESCRIPTION
Referring now in detail to the drawings in which like reference
characters designate like parts, the improved desiccant canister
assembly of the present invention is designed for resiliently or
yieldably compacting a particulate desiccant in a canister to compensate
for variations in the loading and facilitate closing of the feed
end of the canister by a closure responsible for the compacting.
While adaptable for use on other particulate materials and in other
desiccant-type compressed gas filter assemblies, the improved canister
assembly is particularly adapted for use in filter assemblies such
as disclosed in Lanier Frantz U.S. Pat. No. 4029086 and my U.S.
Pat. No. 4113451 in which a particulate desiccant in a canister
is compacted during operation of the filter assembly by a fluid-actuated
compactor, and will be so described as exemplary of the invention.
With the drawings showing only a preferred embodiment of the improved
canister assembly of the present invention, the disclosures of the
above Frantz patents are relied on and incorporated by reference
herein for their showing of compressed gas filter assemblies typifying
those in which the improved canister assembly is particularly adapted
to be used.
The improved desiccant canister assembly, designated as 1 is comprised
of a suitably cylindrical canister or container 2 adapted to contain
or be charged with a load or charge of a particulate desiccant 3
such as a molecular sieve, adapted to selectively adsorb an entrained
contaminant, such as moisture, from compressed gas passing therethrough.
As in the compressed gas filter assemblies of the cited Frantz
patents, the canister 2 is removably insertible or seatable, conveniently
upright or vertically disposed, in a housing of a filter unit of
the filter assembly, in the path of flow of compressed gas therethrough.
Itself open-ended, the canister 2 contains the desiccant charge
3 vertically, axially or at opposite ends between the canister's
inlet, feed, loading, lower or upstream end 4 and a preferably relatively
restricted outlet, upper or downstream end 5 by perforated or foraminous
upper or downstream and lower or upstream end plates 6 and 7 respectively.
Preferably both slidable vertically or axially in and insertible
from the bottom into the canister 2 through the latter's wider feed
end 4 the end plates 6 and 7 for preventing escape of desiccant
particles through their perforations, desirably have fixed, as by
riveting, to their desiccant-confronting faces, fine mesh screens
8.
In the canister assembly 1 the lower end plate 6 is the upper
or inner part or spring-loaded compression plate of a yieldably
or resiliently compressible closure 9 as a whole slidable vertically
or axially in and insertible into the lower end of the canister
2 through the latter's feed end 4 for closing that end after the
canister in inverted position has been loaded with a charge of the
selected particulate desiccant 3. The closure 9 has a lower or outer
part 10 of the illustrated basket or other suitable shape, but,
whatever its shape, that part and the upper or inner part, in the
form of the lower end plate 6 are connected as a subassembly for
limited vertical or axial movement, as by plurality, usually three
or four, of circumferentially spaced bolts 11 and normally spaced
by a plurality of compression springs 12 each loosely encircling
one of the bolts 11 and centered thereon by a grommet 13 on the
bolt and seating against and depending from the upper part 6. Limited
in expansion or relative outward movement or travel by the connecting
bolts 11 the inner and outer parts 6 and 10 of the closure 9 for
protecting the springs 12 from going solid, are limited in compression
or relative inward movement or travel by abutments or stops 14 on
and suitably integral with one or each of the parts and instanding
toward and engageable with a confronting surface on the other part.
In the illustrated embodiment, the basket or cup-shaped lower part
10 of the closure 9 is adapted to house or contain in a compartment
15 about an upstanding tubular central boss 16 a scrubber (not shown),
such as the annular pad of stainless steel wool shown in my U.S.
Pat. No. 4113451 for entrapping or collecting and thus protecting
the bed from progressive clogging by fine oil particles entrained
in the compressed gas being filtered. In turn, the scrubber is protected
from being mashed or otherwise distorted by the bolts 11 on compression
and expansion of the closure 9 by isolating or containing the head
17 of each bolt over the limits of its travel in a plastic or like-capped
well or socket 18 projecting downwardly into the compartment 15
and formed on and depending from a removable cover plate 19 closing
the inner or upper end of the compartment.
With the compartment 15 in the illustrated basket-shaped lower
part 10 contained vertically between the cover plate 19 and the
base 20 of that part and both the base and cover plate perforated
or foraminous over their otherwise free or uninterrupted areas to
pass compressed gas being filtered through that part and thence
through the compression plate 6 to the desiccant bed 3 the lower
part supports the cover plate centrally on the central boss 16 and
at sides on a plurality of vertical ribs or abutments 21 rigid or
integral therewith and each instanding radially from a side thereof
between an adjoining pair of the sockets 18. With the cover plate
19 conveniently screwed to the ribs 21 the lower part 10 centrally
carries or mounts a check valve 22 for bypassing the compressed
gas through the central boss 16 in case the scrubber pad becomes
clogged by entrapped oil. After insertion into the canister 2 the
closure 9 is removably held in place and backed, suitably by a snap
ring 23 inserted into and seating in the feed end 4 of the canister
below or upstream of the closure. If, as illustrated, slidable axially
or longitudinally in the canister 2 the upper end plate 7 in turn
is backed by an annular shoulder 24 instanding thereabove or beyond
and bounding or demarking the canister's outlet end 5.
Constructed in the above manner, the canister 2 inverted and with
the upper end plate 7 in place, is loaded through its feed end 4
with a charge of a small bead molecular sieve or other selected
particulate desiccant 3 to a point where, when the closure 9 is
thereafter inserted into the feed end, the lower or upstream end
of the desiccant bed will be yieldably engaged by the closure's
compression plate 6. By holding the combined force of the compression
springs 12 within a relatively low range, which for the illustrated
three-spring arrangement suitably will be around 15 lbs. (6.75 kgs.)
and the preferred compression range or travel of the closure on
the order of about 1/4 in. (0.635 cm.), the closure is not only
readily insertible into the feed end of the canister after the latter
is loaded and avoids the otherwise necessary preciseness in loading,
but, since partly compressed, provides a spring force for compacting
the desiccant 3 in the interval between the loading of the canister
and its insertion or installation in a housing of a filter unit
of a compressed gas filter assembly, such as shown in either of
the previously mentioned Frantz patents.
As illustrated, the canister assembly 1 is particularly designed
for use in the filter unit of L. Frantz U.S. Pat. No. 4029086
in which, during operation of the filter assembly, the desiccant
3 is compacted by a top acting pneumatic compactor acting downwardly
against the upper end plate 7 the external force exertible on the
canister assembly by the compactor, once activated, usually being
on the order of about 120 lbs. (54 kgs.) in truck and bus installations
of the filter assembly of the L. Frantz patent. The effect of such
activation is to fully compress the closure 9 under the superior
force of the compactor and inactivate its compression springs 12.
However, even though so inactivated, the springs 12 nonetheless
are available for compacting the desiccant 3 should the compactor
be accidentally deactivated or discharged.
When applied to the filter assembly of the above L. Frantz patent
with its top acting compactor, the upper end plate 7 serves as a
floating follower and, backed by the snap ring 23 the closure's
lower part 10 remains stationary and only its upper part or compression
plate 6 moves and then only to the point of full compression. However,
if, as in the filter assembly of my U.S. Pat. No. 4113451 the
pneumatic compactor is bottom acting, the closure 9 must serve as
the floating follower and the upper end plate 7 the stationary reactant.
To adapt it for such use with a bottom acting compactor, the illustrated
canister assembly 1 requires modification but the modification is
slight, involving only the mounting of the check valve 22 inside
the central boss 16 in the manner of the check valve of my patent,
for enabling the compactor to act against the base 20 of the closure
9. With this modification, and the closure 9 the floating follower,
the effect of activation of the bottom acting compactor initially
is, by its superior force relative to that of the springs 12 to
fully compress the closure and thereafter apply the full force of
the compactor in compacting the desiccant.
From the above detailed description it will be apparent that there
has been provided an improved canister assembly having a canister
loadable with a charge of a desiccant or other particulate material,
which, when loaded, has its feed end closed by a resiliently compressible
closure adapted not only to be readily applied and, when applied,
exert a compacting force on the desiccant but also in the presence
of a superior external compacting force, to be fully compressed
for yielding or transferring compaction of the particulate desiccant
or other material to the superior force. It should be understood
that the described and disclosed embodiment is merely exemplary
of the invention and that all modifications are intended to be included
that do not depart from the spirit of the invention and the scope
of the appended claims. |