Abstrict In a compressed gas filter unit including a housing and, for selective
filtering, a particulate desiccant packed in a canister removably
seatable from below in a central bore of the housing, a pneumatic
compactor automatically charged in any filtering cycle of the filter
unit and acting upwardly on the desiccant and therethrough on the
canister for compacting the desiccant and pressing the canister
fluid-tight against a seat therefor at the upper end of the bore.
Claims Having now described my invention, I claim:
1. In a compressed gas filter assembly, the combination, with a
filter unit having a housing removably seating between inlet and
outlet ports thereof an open-ended canister containing a desiccant
for selectively adsorbing a contaminant from gas passing therethrough
between said ports, of sealing means between a downstream end of
said canister and a seat therefor in said housing for sealing between
said ports, and a pneumatic compactor comprising piston means actuated
by compressed gas for applying force to said desiccant and therethrough
on said canister for respectively compacting said desiccant and
pressing said sealing means between said canister and housing for
sealing between said ports.
2. The combination of claim 1 wherein the piston means acts on
the desiccant in a direction to urge the canister into the seat
therefor in the housing for concurrently compacting said desiccant
and by applying therethrough pressure in a seating direction on
said canister maintaining a seal between said ports.
3. In a compressed gas filter assembly, the combination with a
filter unit including a housing having inlet and outlet ports and
a seat therebetween for removably seating an open-ended canister
containing a desiccant for absorbing a contaminant desiccant from
gas passing therethrough between said ports, of resilient gasket
means between said seat and an adjoining end of said canister and
compressible therebetween on pressing of said canister in a seating
direction for sealing between said ports, and a pneumatic compactor
comprising piston means actuated by compressed gas and acting in
a canister-seating-direction on said desiccant for compacting said
desiccant and therethrough compressing said gasket means between
said canister and seat for sealing between said ports.
4. The combination of claim 3 wherein the piston means is automatically
actuated by compressed gas during a filtering cycle of the filter
unit for applying the compacting force to the desiccant and therethrough
sealing pressure on the canister.
5. The combination of claim 4 wherein the piston means includes
valve means normally preventing release of actuating gas from said
piston means during a draining cycle of said unit.
6. The combination of claim 5 wherein the compactor is mounted
in and insertable into and removable from said housing as a unit
on separation of the housing into removably connected parts.
Description BACKGROUND OF THE INVENTION
As pointed out in my copending application Ser. No. 661307 filed
Feb. 25 1976 and the application of Virgil L. Frantz on a Dual
Filter Assembly, Ser. No. 766437 filed Feb. 7 1977 a particulate
desiccant, while highly efficient in selectively adsorbing from
compressed gas an entrained component, such as moisture, due to
the rubbing together of the desiccant particles, tends to release
dust into the gas being filtered, usually to the detriment of devices
activated by the filtered gas. This tendency is minimized by including
in the filter unit a pneumatic compactor such as disclosed in my
application Ser. No. 661307. However, if, as illustrated in that
application, the compactor acts through an interposed floating follower
on the desiccant, in a direction opposite that in which the canister
is inserted in the housing, given a high pressure, high flow installation
such as in the above Virgil L. Frantz application, the effect on
the canister containing the desiccant can be to displace the canister
from its seat in the housing sufficiently to permit a substantial
portion of the compressed gas introduced for filtering into the
housing of the filter unit, to bypass the desiccant and be discharged
without filtering from the housing. It is with preventing this phenomenon,
that the compactor of the present application is particularly concerned.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a pneumatic
compactor for use in a compressed gas filter unit which is effective
to minimize the tendency of a particulate desiccant to produce dust
and in process press a canister containing the desiccant into sealing
engagement with the seat therefore in the filter unit's housing.
Another object of the invention is to provide an improved pneumatic
compactor for a filter unit of a compressed gas filter assembly
which is automatically charged during a filtering cycle of the unit
for both compacting a particulate desiccant and pressing a canister
containing the desiccant against its seat in the unit's housing,
is manually dischargeable for facilitating removal of the canister
for periodic maintenance during a regenerating cycle of the unit,
applies pressure to both the desiccant and the canister by a pneumatically
actuated piston swivelly connected to a floating follower in the
canister, and is itself removably mounted in the housing for periodic
maintenance.
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 housing of a filter
unit showing a preferred embodiment of the improved compactor of
the present invention incorporated in the housing; 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 pneumatic compactor
of the present invention, designated as 1 is adapted for automatically
compacting particulate material when compressed gas for actuation
is available, and particularly designed for use in a filter unit
of a compressed gas filter assembly in which its ability to both
compact a desiccant packed in a canister and maintain sealing engagement
of the canister with its seat in the unit's housing are advantageous.
As typical of an installation having such requirements, the impoved
compactor has been illustrated applied to a filter unit of a dual
filter assembly, such as disclosed in the above-mentioned Virgil
L. Frantz application.
Not only does the present application borrow from the above Virgil
L. Frantz application the setting for a preferred embodiment of
the compactor 1 of the present invention in the form of a suitably
generally cylindrical, vertically disposed housing 2 of one of the
filter units 3 of a dual filter assembly, such as shown in said
Frantz application in FIG. 2 or 4 but the assembly of the latter
application utilizes the compactor 1 of this invention. Since not
necessary for an understanding of the present invention, the housing
2 has been illustrated without the valving at its inlet, outlet
and drain ports, 4 5 and 6 respectively. ordinarily required in
the operation of the housing 2 as part of a filter unit 3 and typified
by the valving disclosed in the previously mentioned Virgil L. Frantz
application. As in the latter application, the housing 2 of the
exemplary installation has upper and lower parts, 7 and 8 respectively,
releasably connected, or attached as by bolting, and both preferably
externally ribbed for improved dissipation of heat to ambient air.
A cylindrical central vertical bore 9 in the housing 2 common to
both of the parts 7 and 8 and exposed on disconnection, thereof,
removably receives or seats a suitably cylindrical canister or container
10 mainly packed with or containing a particulate material 11 which,
for use in a filter unit, desirably is a fine bead or particle desiccant,
most suitably a molecular sieve adapted to selectively adsorb moisture
or other contaminant entrained in and desired to be separated from
the compressed gas to be filtered in the particular installation.
In balance, the illustrated canister 10 contains below or in advance
of the desiccant column or bed 11 a scrubber or scrubbing device
12 including a casing 13 slidable axially in the canister 10 and
having therein a central bypass passage 14 normally closed by a
check valve 15. The scrubber 12 is intended to remove or entrap
fine oil or like particles from the compressed gas being filtered
in advance of the desiccant and performs this function by a suitably
stainless steel annular wool pad 16 received or seated in the casing
13 around and spaced radially outwardly of the central passage 14.
Removably held in the canister 10 conveniently by a snap ring 17
the scrubber's casing 13 has a suitably integral bottom or base
plate 18 having a normally closed central orifice 19 opening into
the bypass passage 14 and, outwardly thereof, being foraminous or
perforated for passing compressed gas undergoing filtering to and
through the pad 16. A foraminous end plate 20 at and removably attached
to the upper or downstream end of the casing 13 separates the desiccant
column 11 and the scrubber 12 and is prevented or barred from directly
contacting the pad 16 by an intermediate annular spacer plate 21
spaced below the separator plate 20 to prevent oil trapped in the
pad from being drawn by capillary attraction into the desiccant
bed 11 through the separator plate.
The canister 10 itself has a perforated or foraminous upper end
22 seating upwardly against and peripherally engageable through
an interposed annular sealing gasket 23 with an opposed annular
shoulder or canister seat 24 in the housing 2 at the upper or downstream
end of the bore 9.
Dirty or contaminated compressed gas enters or is introduced, injected
or passed into the housing 2 through the inlet port 4 and led therefrom
into a downwardly directed helical passage 25 in the housing's upper
part 7 between confronting sides thereof and the canister 10. The
cyclonic flow induced in the entering compressed gas by the helical
passage 25 which centrifugally cools and separates heavier contaminants
from the incoming gas, is broken up by internal baffling in the
housing's lower part 8 as the gas flows past the bottom portion
of the canister 10 to an underlying sump 26 in the lower part. The
sump collects the previously separated contaminants and reverses
the direction of flow of the compressed gas for upward flow through
the canister 10 to an overlying outlet passage 27 in the upper end
of the housing 2 leading to the outlet port 5 from which the gas
exits or is discharged as filtered or decontaminated product compressed
gas. So operating in a filtering cycle, the filter unit 3 in a
draining or regenerating or purging cycle, has its inlet and outlet
ports 4 and 5 closed except for a restricted reverse flow at low
pressure of previously filtered gas through the canister 10 and
the then open outlet port 6 to ambient air for regenerating or purging
both the desiccant 11 and the scrubber pad 16.
As mentioned in both my copending application and the application
of Virgil L. Frantz, earlier referred to, the constant exposure
of the particles or beads of the preferred molecular sieve desiccant
11 to gas flowing first in one direction and then in the other,
ordinarily causes the particles to abrade or rub against each other
and produce dust which is carried off by the filtered gas to the
detriment of any operating devices on which the product gas is used.
Too, in a filter assembly, such as illustrated, in which the canister
10 separates the outlet port 5 from the inlet port 4 it is vital
that sealing engagement between the downstream, here upper, end
22 of the canister 10 and its seat 24 in the housing 2 at the upper
end of the bore 9 be maintained, at least during the filtering
cycle of the filter unit 3 to prevent a substantial portion of
the compressed gas injected into or entering the housing 2 from
being shunted past the canister from the inlet port directly to
the outlet port and discharged, unfiltered, from the latter port.
Even with the circumferential O-ring seal of Lanier Frantz application,
Ser. No. 661307 and, as there illustrated, the compactor acting
in a direction to dislodge or unseat the canister, no particular
problem is presented in truck, bus and rapid transit car installations,
since the gas pressures usually obtaining or prevailing in such
installations are insufficient to disrupt the seal between the canister
and the housing. However, under higher gas pressures, such as present
in diesel locomotive compressed air filter assemblies, the application
of compacting pressure to the desiccant 11 in a direction to dislodge
the canister 10 from its seat 24 renders substantial leakage around
the dowstream end of the canister likely, regardless of the type
of gasket employed for sealing. In the present invention, the possibility
of such leakage is avoided without adverse effect upon the compacting
action of the compactor 1 upon the desiccant beads 11 by applying
the compacting pressure in the seating direction of the canister
10 and applying that pressure through the canister to a resilient
or compressible gasket 23 interposed between the seat 24 and the
confronting end 22 of the canister.
In the illustrated preferred embodiment, the improved pneumatic
compactor 1 is comprised of a valve chamber 28 in an open-bottomed
cup or container 29 in which rides or slides axially, here vertically,
a head 30 of a piston 31 the stem 32 of which projects upwardly
through the cup's upper wall 33 and has a ball-shaped upper or outer
end 34 ball-and-socket connected to and swivelly mounting a self-aligning
spider 35 straddling the central orifice 19 in and engaging the
bottom plate 18 of the scrubber's casing 13. With the scrubber 12
then serving as an intervening floating follower, the compactor
1 is adapted to apply an upward force for compacting the desiccant
11 within the canister 10 between the scrubber and the canister's
upper end 22 and, through the desiccant, applying the compacting
force of the compactor to press or urge the canister in an upward
or seating direction and compress the gasket 23 between the canister's
upper end 22 and the seat 24 therefor in the housing, thus ensuring
against or inhibiting any leakage of entering compressed gas therepast
between the inlet and outlet ports 4 and 5.
For enabling the compactor 1 in applying or exerting pressure
on the desiccant 11 and therethrough the canister 10 to react downwardly
or oppositely against the housing 2 the cup 29 is seated or socketed
in an upwardly opening, suitably cylindrical central socket 36 in
a mounting block 37 seated from within in the sump 26 and containing
below and separate from the socket the drain port or opening 6 of
the housing 2. The drain port opens onto or communicates with the
sump 26 through suitably cresent-shaped apertures 38 each at the
bottom of one of the sectors 39 into which the suitably conical
lower part of the sump 26 is divided by radially projecting slots
40 in which seat or are received radial arms or abutments 41 of
the mounting block 37 through which the block is bolted or otherwise
releasably secured in the housing 2.
Connected at the bottom and top, respectively to the drain port
6 by a supply passage 42 and to atmosphere by a bleed passage 43
the valve chamber 28 during the filtering cycle of the filter unit
3 is open to receive from the drain port actuating gas below the
head 30 of the piston 31 for urging the piston upwardly or in a
downstream direction in terms of the flow of compressed gas through
the filter unit 3 while eliminating resistance by back pressure
to upward movement of the piston by bleeding or venting gas above
the piston head to atmosphere through the bleed passage 43. Once
charged or pressurized, the pneumatic compactor 1 is prevented from
being accidentally discharged during a regenerating cycle of the
filter unit 3 by a check valve 44 in the supply passage 42 while
adapted for intentional discharge through the same passage during
a regenerating cycle by manual actuation of a plunger 45 to open
or unseat the check valve.
Conveniently attached to the housing's lower part 8 by interiorly
accessible bolts 46 the compactor 1 is readily removable as a unit
from the lower part on detachment of the latter from the upper part
7 in gaining access to the central bore 9 for periodic inspection
of the canister 10 and its contents. Then in a discharged or deenergized
condition, the compactor 1 once the filter unit 3 has been reassembled,
will automatically be recharged or reenergized in the unit's next
filtering cycle.
From the above detailed description it will be apparent that there
has been provided an improved pneumatic compactor for compacting
a particulate desiccant or other particulate material, which depends
for compacting the material on the availability of actuating compressed
gas, is proof against accidental while adapted for intentional discharge
and, as applied to a unit containing the particulate material in
a canister, is capable of utilizing the compacting pressure applied
to the particulate material for maintaining sealing engagement between
the canister and the unit's housing. 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.
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