Note: Descriptions are shown in the official language in which they were submitted.
~ 7'7t~
SELF-CLEANING PULSED AIR CLEANER
Technical Field
This invention relates to the field of air
cleaning by removal of particulate matter such as dust,
particularly in installations requiring treatment of large
volumes of air.
Background of the Invention
The removal of dust is accomplished by passing
the air through a filter of material permeable to flow of
gas but not to passage of particulate matter, which col-
lects on the filter thus gradually filling its pores and
increasing the restriction of the cleaner, that is, the
pressure drop across the filter and the load on the
air-moving fan or blower. A successful air cleaner must
accordingly have a large enough area of filter medium to
reduce the initial restriction to an acceptable level, and
must be either cleaned or replaced at sufficiently fre-
quent intervals to prevent dirt buildup to a point where
the restriction is adversely affective.
Means have been devised for cleaning filters,
even without interrupting system operation, by mechanical
r~
~7'7t~3
shaking or by reverse air jet pulsing. The latter clean-
ing procedure is successful, when the filter medium is
pleated paper, in releasing the particulate matter from
the mediumr but the resumption of normal airflow through
the filter at the end of each pulse in large measure draws
the particles back against the filter medium, thus greatly
reducing the cleaning efficiency. This is particularly
noticeable in installations which because of the large
volume of air to be treated require large areas of filter
medium.
Brief Summary of the Invention
One aspect of the present invention relates to
an air cleaner with pulse jet cleaning in which the filter
medium is positioned and the gas flow is directed so that
particulate matter initially impinging on the filter
medium is enabled and impelled to "migrate" across the
medium during successive cleaning pulses and to ultimately
reach a scavenge site where it can be discharged from the
cleaner, always without interruption of the cleaning
operation.
Other embodiments of the present invention relate to
an air cleaner with pulse jet cleaning and an integral
precleaner.
In accordance with one of these embodiments,
there is disclosed an air cleaner apparatus for removing
particulate matter from air comprising a housing having an
unfiltered air inlet and a filtered air outlet, a filter
assembly within the housing including a filter having a
filtered air side and an unfiltered air side, the filtered
air side being isolated from unfiltered air, inertial
7 ~, ~3
precleaner means located proximate the unfiltered air side
and defining an intermediate space therebetween, the
precleaner means for reversing the flow of unfiltered air
thereby inertially separating particulate matter, reverse
pulse cleaning means for intermittently directing a re-
verse flow of air toward the filtered side of the filter
so that particulate matter will become dislodged from the
unfiltered air side and enter the intermediate space,
closure means responsive to the reverse flow of air for
blocking passages of the reverse flow through the inertial
precleaner means, and an outlet means in said intermedate
space for exhausting the reverse flow of air so that
particulate matter in the flow will not be reentrained on
the unfiltered side of the filter.
In accordance with other aspects of the inven-
tion, there are disclosed a number of embodiments relating
to closure means described above and one embodiment having
the above elements without the inertial precleaner means.
There have this been outlined rather broadly the
more important features of the invention in order that the
detailed description thereof that follows may be better
understood, and in order that the present contribution to
the art may be better appreciated. There are, of course,
additional features of the invention that will be de-
scribed hereinafter and which will form the subject of the
claims appended hereto. Those skilled in the art will
appreciate that the conception upon which the disclosure
is based may readily be utilized as a basis for the de-
signing of other structures for carrying out the several
purposes of the invention. It is important, therefore,
~ 7 ~ t~3
that the claims be regarded as including such eguivalent
structures as do not depart from the spirit and scope of
the invention.
Brief Description of the Drawing
In the drawing, wherein like reference numerals
refer to like elements throughout the several views,
FIGURE 1 is a plan view of an air cleaner accor-
ding to the invention, parts being broken away;
FIGURE 2 is a view generally in vertical section
looking along the line 2-2 of FIGURE l;
FIGURE 3 is a view in perspective of a filter
assembly used in the air cleaner of FIGURES 1 and 2;
FIGURE 4 is a view in horizontal section looking
along the line 4-4 of FIGURE 3;
FIGURE 5 is a somewhat schematic view in section
of a second embodiment of the invention;
FIGURE 6 is a schematic wiring diagram;
FIGURE 7 is a plan view of an alternative em-
bodiment of an air cleaner according to the invention,
with parts broken away and shown in section;
FIGURE 8 is a view generally taken in vertical
section looking along line 8-8 of FIGURE 7;
FIGURE 9 is an elevational view looking from
line 9-9 of FIGURE 7;
FIGURE 10 is an enlaxged fragmentary sectional
view of a filter assembly as seen from line 10-10 of
FIGURE 8;
FIGURE 11 is a view generally in end elevation
looking from line 11-11 of FIGURE 10;
--4--
~ ~ ~7~t~3
FIGURE 12 is a view generally taken in section
looking along line 12-12 in FIGURE 10;
FIGURE 13 is an enlarged view of a portion of
the louvered structure shown in FIGURE lQ;
FIGURE 14 is a plan view of an alternate lou-
vered portion of a filter assembly used in the air cleaner
in FIGURES 7 and 8;
FIGURE 15 is an elevational view seen from line
15-15 of FIGURE 14;
FIGURE 16 is a fragmentary sectional view taken
along line 16-16 of FIGURE 14;
FIGURE 17 is a schematic wiring diagram;
FIGURE 18 is a view similar to FIGURE 15 with
portions broken away showing a further embodiment of the
present invention;
FIGURE 19 is a portion of a view similar to
FIGURE 7 showing a further embodiment of the overall air
cleaner according to the invention;
FIGURE 20 is a view similar to FIGURE 13 showing
an alternative embodiment of the louvered structure;
FIGURE 21 is a sectional view taken along line
21-21 of FIGURE 19; and
FIGURE 22 is a sectional view similar to a
portion of FIGURE 10, but showing the alternate form of
FIGURES 19 and 20.
Detailed Description of the Invention
The embodiment of the invention shown in FIGURES
1 and 2 comprises an airtight housing 20 having a remov-
able or hinged top 21, a bottom 2~, opposite sides 23 and
~4, opposite ends 25 and 26, and a vertical partition 27
~ ~7~3
which divid~s the housing into a larger chamber 30 and a
smaller chamber 31. Bottom 22 is configured to provide a
scavenge chamber 32 to which there is connected a scavenge
duct 33. An inlet 34 for air to be cleaned is provided in
top 21 near end 25, which is closed, and a draft opening
35 may be provided in top 21 opening into chamber 30 near
partition 27. An outlet 36 for cleaned air is formed in
end 26. Partition 27 is provided with a plurality of
apertures 37, 38, 40 so that a path for air flow extends
from inlet 34 through chamber 30, apertures 37, 38 and 40,
and chamber 31 to outlet 36, as suggested by the arrows in
FIGURE 2.
A plurality of filter assemblies 41, 42 and 43
are mounted on partition 27 to close openings 37, 38, and
40. To accomplish this an upper rod 180 and a lower rod
181 are secured at first ends to partition 27, between
filters 41 and 42, and a second pair of rods are similarly
secured between filters 42 and 43. A clamping frame 182
comprising upper and lower horizontal channels 183 and 184
and vertical legs 185 and 186 is secured to the rods by
nuts 187. Pressure pads 190 are provided between the
channels and the filters. Legs 185 and 186 are extended
downward to rest on bottom 22. Deflectors 191 of sheet
metal are secured to extend vertically between the rods by
clips 192, for a purpose presently to be described.
The filter assemblies are alike, and assembly 41
is shown in FIGURES 3 and 4 to comprise first and second
flat filters 44 and 45 mounted on edge in a frame 46 with
a tapering space 47 between them to converge toward a
first, closed end 50 of the frame. The opposite end 51 of
77~3
the frame is open, and is dimensioned to be seated against
one of the openings in partition 27 and be sealed with
respect thereto by a suitable gasket 52. A top 53 and
bottom 54 of frame 46 are closed, and a pair of horizontal
partitions 55 and 56 provide strength and rigidity to the
assembly, and divide the tapering space 47 between the
filters into an upper chamber 60, a middle chamber 61, and
a lower chamber 62.
Each of filters 44 and 45 is made up of a body
of pleated paper filter medium 63, contained between inner
and outer sheets 64 and 65 of perforated metal or similar
material, the whole being unified by stripes 66 of plastic
or cemellt. The pleats of the filter medium run verti-
cally, as is shown.
It will be apparent that assemblies 41, 42, and
43 divide chamber 30 into first and second portions of
irregular outline, the first portion being that space
outside of the filter assemblies, and the latter portion
being the sum of the tapering spaces inside the filter
assemblies.
Turning again to FIGURES 1 and 2, a horizontal
partition 70 is provided in chamber 31, so that the space
71 below the partition comprises a reservoir for air for
cleaning the filter, which air is supplied through a duct
72. A number of standpipes 73, 74, 75 equal tG the number
of filter assemblies extend upwardly from partition 70,
each supplying air from the chamber to a number of valves
equal to the number of chambers in the tapered space 47 of
a filter assembly. Thus standpipe 73 is connected to and
supports an upper valve 76, a center valve 77, and a lower
~ 3
valve 78. The valves connect with nozzles 80, 81, and 8~
respectively, and are positioned so that the nozzles are
directed centrally into chambers 60, 61, and 62 of the
apposed filter assembly 42. Standpipes 74 and 75 are
similarly equipped with valves and nozzles, of which
valves 83 and 84 and nozzles 85 and 86 are shown in FIGURE
2.
Between the nozzles and partition 27 are mounted
a set of diffusers 90, 91, and 92, aligned with standpipes
73, 74, and 75 respectively. The partitioning of the fil-
ter assemblies into vertically arranged chambers, the
provision of plural nozzles, one for each chamber, and the
interposition of diffusers between the nozzles and the
chambers has been found to optimize the efficiency of
pulse jets in releasing particulate matter from the fil-
ters, as will be explained below.
Preferably valves 75, 76, etc. are normally
closed, solenoid valves actuated electrically at brief
intervals to emit pulses of air through the associated
nozzles 80, 81, etc.
By a suitable switching circuit suggested in
FIGURE 6 and including a timer 93 the valves are energized
so that jets are directed simultaneously into the upper
chambers of the filter assemblies, then into the center
chambers, and then into the bottom chambers, in a repeat-
ing cycle: the length of the cycle and the lengths of the
pulses within the cycle and their spacing may be varied at
the will of the operator, to maximize the cleaning effect
in dependence on the nature of the particulate matter be-
ing removed.
7 7~3
Operation
In operation top 20 is opened and a pluraltiy ofclean filter assemblies 41, 42, and 43 are inserted and
secured in sealed relation to partition 27. Top 21 is
closed, an inlet duct for air to be cleaned is connected
at 34, an outlet duct for clean air is connected at 36, a
source of air under negative pressure is connected to duct
33, and a source of air under positive pressure is con-
nected to duct 72. To set the cleaner in operation,
electrical energy is supplied to timer 93, and airflow
through the cleaner is started, ordinarily by a pump or
fan connected to outlet 36.
Particles of dirt carried by the air entering
the cleaner at 34 are initially collected on the outer
surfaces of the filters in assemblies 41, 42, and 43.
Timer 93 operates to supply a pulse of air from reservoir
71 through standpipes 73, 74, and 75 and valves 83, 76,
and 84 to upper nozzles 85, 80, and 86, which project jets
of air past diffusers 90, 91, and 92 into the upper cham-
bers 60 of the filter assemblies, interrupting the flow ofair inwards through the filters and momentarily dischar-
ging dirt particles from the outer surfaces of the fil-
ters. Deflectors 191 are provided to prevent particles
expelled from one of the filters from being forcibly
jetted across the space between filters to impinge on the
adjacent filter. The particles start to descend by grav-
ity into the normal airflow below, but upon termination of
the cleaning pulses normal air flow is resumed and the
particles are again brought into contact with the filters,
at sites lower and nearer to partition 27 than initially.
~. 9 ~7~3
Pulses of air are then supplied in sequence to the center
and the lower chambers of the filter assemblies, again
dislodging particles of dirt and enabling them to move.
The downward movement of particles near partition 27 is
facilitated if a small quantity of ambient air is admitted
at draft opening 35. The dust particles partake of a
motion of migration across the surfaces of the filters and
ultimately reach scavenge opening 32, from which they are
extracted by duct 33, together with a small quantity of
the air entering at 34 and 35.
In one embodiment of the invention the volume of
chamber 71 was one cubic foot, cleaning air was supplied
at 100 pounds per square inch, and the pressure dropped to
65 pounds per square inch during the pulses. These dimen-
sions will naturally vary with the size of the installa-
tion: the one referred to had a capacity of 8,000 cubic
feet per minute of air at inlet 34.
Structure of the Second Embodiment
A second embodiment of the invention is shown
somewhat schematically in FIGURE 6 to comprise a housing
100 divided by a partition 101 into a lower, larger cham-
ber 102 and an upper, smaller chamber 103. Air to be
cleaned is admitted to the housing at an inlet 104 near
the bottom, and cleaned air is taken from the cleaner at
an outlet 105, in its top. A reservoir 106 is supplied
with air for the cleaning function by a duct 107, and
standpipes, valves, nozzles, and deflectors may be sup-
plied as described above. Filter assemblies such as
assembly 110 are supported on and sealed to partition 101,
and may be as shown in FIGURES 3 and 4.
--10--
~ ~ ~ 7~ ~3
Housing 100 is provided with a vertical parti-
tion 113 to define a scavenge plenum 114, connected to a
scavenge duct 115, and a plurality of apertures 116, 117,
120, and 121 provide communication between chamber 102 and
plenum 114.
Operation
The operation of the second embodiment of the
invention is as described earlier. Particles of dust ini-
tially collecting on the surfaces of the filters, are
momentarily released by the cleaning jets, and migrate
across the filter sur~aces. In this embodiment upward
movement is caused by the normal flow of the air into the
housing, and movement to the left is caused by the nega-
tive pressure maintained in scavenge plenum 114. The
drawing shows that no draft opening is provided in this
housing, so the cleaner can be used in a system where air
is forced into inlet 104 rather than being drawn from
outlet 105. In both of the embodiments the matter removed
in the scavenge duct is disposed of in conventional fash-
ion.
Alternate Embodiments Including Integral Precleaner
Alternate embodiments of the present inventionincluding an integral precleaner are shown in FIGURES
7-22. Several alternative embodiments within this group
of figures are shown and will be explained hereinafter.
The embodiment shown in FIGURES 7-13 comprises
an airtight housing 220 having a hinged section 222 for
intake of unfiltered air which pivots on hinge 224 and is
held in a closed position by locking means 226. FIGURE 7
shows left wall 228 and right wall 230 while FIGURE 8
~7'~ ~j3
shows the top wall 232 and the bottom wall 234. Portions
236 and 238 form the side and bottom walls of the hinge
section 222.
Within housing 220 are located a plurality of
filter assemblies 240, 242, and 244. The filter assem-
blies are held in housing 220 by bolts 246 and plates 250
and 252 at their respective ends. Plate 252 includes
apertures 254, 256, and 258. Located proximate apertures
254-258 are pulse jets 260a-c, 262a-c, and 264a-c. Their
relative orientation can best be seen in FIGURE 9. Each
pulse jet 260-264 is designed to supply a high velocity
stream of air for reverse pulse cleaning of the filter
assemblies. The pulse jets are of the same general nature
as those in the earlier embodiment designated generally by
the numbers 73, 76, and 80; however, a diffuser 90 used in
the previous embodiment is optional. The pulse jets are
connected to conduits 266, 268, and 270, which direct the
air therethrough.
Hinge section 222 includes a plurality of pas-
sageways 272, 274, 276 which are formed of a plurality ofpartitions 278, 280, 282, and 284, and which are curved as
shown in FIGURE 8. The conduits are aligned so as to
provide a flow of unfiltered air to the filter assemblies,
as will be explained hereinafter.
Turning temporarily to the individual filter
assemblies, attention is directed to FIGURES 1~-12. Basic
components of the filter assemblies 240-244 are the same
as assembly 41 shown in FIGURES 3 and 4 of the previous
embodiment. To the extent variations are not explained
herein, reference should be had to those figures for a
detailed description.
-12-
~ ~7~3
All of the filter assemblies are alike. Filter
assembly 240 is shown in FIGURES 10-12 to comprise first
and second flat filters 286 and 288 (each having a fil-
tered and unfiltered face 287a and 287b respectively)
mounted on edge in a frame 290 with a tapering space 292
between them to converge toward a first closed end 294.
The opposite end 296 is opened and is dimensioned to be
seated against one of the openings 254-258 in plate 252
preferably with a gasket seal 298 to ensure an airtight
connection. The top 300 and bottom 302 of frame 290 are
closed, thereby enclosing the "filtered" side of the
filter assembly, and a pair of horizontal partitions 304
and 306 provide strength and rigidity to the assembly as
well as dividing space 292 into an upper chamber 292a,
middle chamber 292b, and lower chamber 292c. Each of
filters 296 and 288 is made up of a body of pleated paper
filter medium 306 contained between inner and outer sheets
308 and 310 of perforated metal or similar material.
Surrounding frame 290 is the precleaner enclo-
sure 312 which surrounds frame 290 on face 287a. Betweenenclosure 312 and frame 290 there is defined an inter-
mediate space 314. Enclosure 312 includes two louvered
panels 316a and 316b which are mirror images of each other
and which are joined by a second end panel 318. The
remaining portions of enclosure 312 abut frame 290 at
gasket 298.
Louvered panels 316a and 316b can be more clear-
ly seen in FIGURE 13 of the drawings. In view of the sym-
metry of panels 316a and 316b, only one will be discussed
in detail. Panel 316a includes a plurality of successive
7'7~3
louvers 319 which are preferably stamped out of a planar
sheet so as to create the overall shapes most clearly
shown in FIGURE 12, having a rising portion 320 and side
sloping portions 322. The angle of inclination of portion
320 relative to the planar sheets 316a and 316b may be
predetermined according to desire at manufacture to en-
hance the precleaning effect according to particular gas
densities and pressures to be applied to this device.
Each louver provides a passageway 324 between
the intermediate chamber 314 and interior space 221 within
housing 220.
Affixed to the other side of plate 312, proxi-
mate space 314, by fasteners 326 are flaps 328. Flaps 328
are preferably made of a flexible material, such as rubber
or plastic, so that they may move from a position blocking
the passageways 324 to a position extending into inter-
mediate space 314 thus opening the passageways in response
to air pressure changes within the intermediate space.
When flaps 328 are in a blocking position, there will be
contact between the flap and end portion 330 of each
louver 320.
As can be seen in FIGURE 10, within the interior
space 314, proximate end 318, a scavenge outlet 332 is
provided. The scavenge outlets for each filter assembly
240-244 are collected by a manifold 334 as shown in FIGURE
7. As a scavenging outlet for air within the interior
space 221, ports 336 are provided (as seen in FIGURE 7),
which connect to manifold 338, which is ultimately ex-
hausted to the outside environment.
-14-
~L577~3
Operation
This embodiment of the present invention effec-
tively provides a dual filtration of uncleaned air and a
superior means for reverse pulse cleaning of the filter
element.
The first filtration of uncleaned air is accom-
plished by inertial separation. Uncleaned air enters con-
duits 272-276 (FIGURES 7 and 8) and enters interior space
221 o housing 220. Arrows 400 in conduits 272-276 indi-
cate the direction of air flow. The air within space 221will travel in a direction generally toward ports 336. As
the air passes through louver 318, it will reverse direc-
tions approximately 180 so as to enter passageway 324 as
shown by arrows 402 in FIGURES 7 and 13. Because the
particulate matter, which is of a greater mass than air,
inertial forces of such magnitude are achieved so as to
preclude the particles from reversing direction as they
pass the louvers, a substantial portion of the heavier
particulate matter will be separated out and continue to
flow in a linear direction into ports 336. Therefore, the
air entering passageways 324 will be precleaned.
The air now enters intermediate space 314 in the
direction shown by arrows 404 in FI~URE 13. The filtering
medium 286 removes most of the remaining particulate
matter and allows the air to exit the filter in the direc-
tion shown by arrows 406 in FIGURE 13. Finally, the clean
air will exit the filter through apertures 254-258 in the
direction shown by arrows 408 in FIGURE 7.
As the filter medium 286 becomes filled with
particulate matter, it will be necessary to purge the
~ 7~ 3
medium with a reverse pulse of air from pulse jets
260-264. This reverse flow of air is shown by arrows 410
in FIGURE 10 and FIGU~E 13.
During the period when the reverse pulse of air
is activated, particulate matter will be blown off the
surface of filter medium 286 into intermediate space 314.
This reverse pressure will immediately cause flap 328 to
become biased against edge 330, thereby closing passageway
324 (FIGURE 13). The only remaining path for the reverse
pulse of air will then be toward port 332 and into mani-
fold 334. This will effectively sweep this particulate-
laden purging air flow out of the system to prevent the
major portion of the particulate matter from being re-
lodged on the filter medium. Because flaps 328 are
flexible and preferably slightly curved, they will tend to
deflect the reverse flow in the direction of port 332
shown by arrows 412. In addition, their flexibility will
tend to allow the formation of a greater curvature during
the period when they are in the process of closing pas-
sageway 324.
In order to provide for continuous operation ofthe filter, it is not possible to provide reverse pulse
cleaning of all sections of the filter simultaneously. By
specifically sequencing the portions of each filter assem-
bly which shall be purged, it is possible to cause a
general migration of particulate matter in a direction
shown by arrows 414 in FIGURE 8. By utilizing this
migrating effect, the filter assemblies tend to be
self-cleaning by ultimately siphoning off the accumulated
particulate matter through apertures 332 at the bottom of
the intermediate space 314 (see FIGURES 8-10) and by
-16-
11 ~7~3
sweeping this matter away through conduit 334 as shown byarrow 344.
Alternate Embodiment
The embodiment disclosed in FIGURES 19-21 is
considered the preferred embodiment at this time. Many of
the features of this embodiment are identical with those
of the previous embodiments and will therefore not be
reiterated. The changes made in this embodiment over the
previous embodiment are shown in FIGURES 19-21. In order
to simplify the air flow within intermediate chamber 314a
as shown in FIGURE 20 and eliminate port 332, flaps 328a
have been reversed (see FIGURE 13 for comparison). In
FIGURE 20, it can be seen that each of flaps 328a is fixed
to the next leading louver 319a so that the curl of the
flap is reversed. As mentioned previously, it is this
curvature or curl which aids in urging the reverse air
pulse shown by arrows 412a in flowing in a particular
direction during the time and after passageways 324a are
closing. As can be seen in FIGURE 20, the air flow of
uncleaned air outside the louvers indicated by arrows 414
and the air flow of the reverse air pulse indicated by
arrows 412a is generally in the same direction. This
aspect allows for simplification of the scavenging system
for intermediate space 314a. As seen in FIGURE 22, the
termination of plate 312a proximate gasket 298a has been
altered as compared with the previous embodiment shown in
FIGURE 10. In this embodiment, in FIGURE 22, ports 416 at
the ends of intermediate space 314a provide an outlet
passage (FIGURE 21) for this flow of air which is col-
lected in manifold 338a. The direction of air flow is
t7~ 3
indicated by arrows 422 in FIGURE 21. It is noted that
manifold 338 is the same manifold whlch collects the heavy
particulate matter initially separated in space 221 during
the first phase of precleaning. Manifold 338a corresponds
substantially to manifold 338 in the previous embodiment
shown in FIGURE 7.
Thus, by reversing the direction of air flow
within intermediate chamber 314a, as shown by arrows 412a,
as a consequence of the orientation of flaps 328a, it is
possible to eliminate port 332 and manifold 334 which were
employed in the previous embodiment. The present embodi-
ment uses manifold 338 to collect scavenged air during
reverse pulse jet cleaning.
Alternate Embodiment Having Adjustable Louvers
This embodiment of the present invention con-
tains many of the features and elements shown in the
previous two embodiments, and to the extent these features
or elements are not repeated, they should be considered to
be generally the same.
This embodiment allows for the mechanical ad-
justment of the angle of inclination of the louvers either
by mechanical or electromechanical means. This adjust-
ability feature may allow for the elimination of flaps 328
or 328a by mechanically closing louvers 319b (FIGURES 14,
15, and 18) at the appropriate time. In addition, the
adjustability of louvers allows selection of the proper
angle of inclination to most effectively separate particu-
late matter of a particular mass carried in a gas at a
particular air flow or pressure.
-18-
7'.~
FIGURES 14 and 15 disclose the electromechanical
version of this embodiment concerning filter assembly
240b. As in previous embodiments, each filter assembly
has two louvered panels 316c and 316d which are symmetric
with respect to each other. The louvers 319b are closed
at their lateral ends 502. Each louver 319b includes a
tubular member 503. The members 503 are axially aligned
with cooperating tubular members 505 fixedly carried by
panels 316c and 316d. Pivot rods 504 are received within
respective cooperating tubular members 503 and 505 to
pivotally mount louvers 319b. A lever member 506 is
attached to louver 319b and the pivot points each have
members 506 pivotably attached to control arm 508. Filter
assembly 240b is divided into three sections, 261a, b, and
c, as in the previous embodiment.
In order to obtain the migrating effect dis-
cussed in the previous embodiment, it is desirable to
reverse pulse clean each section sequentially a to c so as
to cause particulate matter to migrate towards the bottom
of the filter. (Note that FIGURE 14 is shown upsidedown.)
To accomplish this, the louvers of each section are con-
nected together by an individual connecting member 508.
Each connecting member is individually operated by rack
and pinion systems 514, 516, and 518, respectively, one of
which is shown in detail in FIGURE 16. Three pivot rods
504 include pinion gears 520, 522, and 524, which have
meshing engagement with a rack and roller system 526, 528,
and 530 respectively. The roller holds the rack in place
while the rack engages the pinion gear. The rack is
adjustably connected to solenoid armatures 532, 534, and
--19--
~ 7-'~ 3
538 by means of a fastener through a slot in a portion of
the armature. The armature resides within a solenoid 540,
542, and 544, which is adjustably affixed to the filter
assembly by means of fasteners in a slotted base. The
adjustment of the solenoids allows for presetting the
angle of inclination of the louvers. Pinion gear 520 is
coupled to the louvers in filter section 261a by pin 546.
Similarly pinion gears 522 and 524 are coupled to the next
succeeding filter sections by pins 548 and 550. The
remaining pivot rods 504 do not rotate themselves and are
fixed by pins 552, which pass through tubular members 505
and respective rods 504, as seen in FIGURE 14. This
allows their respective louvers to rotate freely in
response to movement of respective control rods 508.
The circuit shown in FIGURE 17, which is used to
operate the pulsed jets, may also be coupled to solenoids
540-544 so as to electromagnetically close the proper sec-
tion of louvers when reverse pulse jet cleaning is being
undertaken.
In the circumstance where it is not desired to
close louvers 319b but adjustability is an important
factor, the manually adjustable system 240c disclosed in
FIGURE 18 is available. Replacing solenoids 540-544 are
plates 602-606, which have integral handles 608-612. The
plate is pivoted on pivot points and locking nuts 614-18
as it controls the racks and pinions 626-30 as at 630-24.
Either the electromechanical or the simple
mechanical louver-adjusting system disclosed above may be
used in conjunction with either of the air flow patterns
for the scavenging suggested in the previous embodiment.
-20-
1J ~'7'~tj3
Therefore, in FI~URE 15, port 332 drawn in phantom lines
may be eliminated and ports such as 416 in FIGURES 21, 22
substituted therefor.
FIGURE 17 discloses a simple schematic diagram
of the preferred electrical hookup of solenoid valves 450,
452, and 454 which control pulse jets 260a, 262a, 264a
(for 450), 260b, 262b, 264b (for 452) and 260c, 262c, 264c
(for 454) and solenoids 540, 542, and 544 etc. which
control the louvers. Control box 456 would be in the
nature of electronic or electromechanical seguencing means
to operate the three parallel circuits in a desired se-
quence.
It is noted that it is also possible to practice
this invention without the precleaner. The embodiments
shown in FIGURES 7-13 would be modified by removing the
louvers and leaving the passageways and flaps. The device
would then have the same reverse pulse cleaning and migra-
tion properties of other embodiments described herein.
Numerous characteristics and advantages of the
invention have been set forth in the foregoing descrip-
tion, together with details of the structure and function
of the invention, and the novel features thereof are
pointed out in the appended claims. The disclosure,
however, is illustrative only, and changes may be made in
detail, especially in matters of shape, size, and arrange-
ment of parts, within the principle of the invention, to
the full extent of the broad general meaning of the terms
in which the appended claims are expressed.
