U.S. patent number RE32,185 [Application Number 06/683,406] was granted by the patent office on 1986-06-17 for self-cleaning pulsed air cleaner.
This patent grant is currently assigned to Donaldson Company, Inc.. Invention is credited to George A. Copley.
United States Patent |
RE32,185 |
Copley |
June 17, 1986 |
Self-cleaning pulsed air cleaner
Abstract
An air cleaning method and apparatus in which air to be cleaned
is drawn toward and through a filter (44, 45) along a normal path
having a first component extending from a first to a second end of
the filter, so as to initially collect particulate matter on the
filter, in which momentary pulses of clean air are directed through
the filter in a direction opposed to the normal path, to interrupt
flow of the air in the normal path so as to dislodge collected
particles from the filter and enable migration of the particles
toward the second end of the filter, and in which the migrated
particles are withdrawn, in a portion of the air, from a site (33,
115) near the second end of the filter.
Inventors: |
Copley; George A. (Farmington,
MN) |
Assignee: |
Donaldson Company, Inc.
(Minneapolis, MN)
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Family
ID: |
27393530 |
Appl.
No.: |
06/683,406 |
Filed: |
December 19, 1984 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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195873 |
Oct 10, 1980 |
4331459 |
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Reissue of: |
338308 |
Jan 11, 1982 |
04364751 |
Dec 21, 1982 |
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Current U.S.
Class: |
95/280;
55/302 |
Current CPC
Class: |
B01D
46/0068 (20130101); B01D 46/521 (20130101); B01D
46/125 (20130101) |
Current International
Class: |
B01D
46/52 (20060101); B01D 46/10 (20060101); B01D
46/12 (20060101); B01D 50/00 (20060101); B01D
046/04 () |
Field of
Search: |
;55/96,97,302,272,273 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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248453 |
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Dec 1963 |
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AU |
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447061 |
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Mar 1948 |
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CA |
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17590 |
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Oct 1980 |
|
EP |
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2550918 |
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May 1977 |
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DE |
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2730925 |
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Jan 1979 |
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DE |
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1563990 |
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Mar 1969 |
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FR |
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2009625 |
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Feb 1970 |
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FR |
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2401690 |
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Mar 1979 |
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FR |
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1016556 |
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Jan 1966 |
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GB |
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Other References
"Slim Vee Pac-2, Non-Stop Protection for Locomotive Engines",
Bulletin 1200-239, Publication 10 M 874 FP, Copyright 1974 by
Donaldson Company, Inc. (6 pages). .
"Donaldson Gas Turbine Product News: Slim Vee Pac High-Efficiency
Barrier Filter", Bulletin 3000-9, Publication 1 M 275 FP, Copyright
1974 by Donaldson Company, Inc. (2 pages). .
"Pulse Clean: Air Filter for Turbine Intake Applications",
Publication EC-1-115B-OCT-03, by American Air Filter Co., Inc. (6
pages)..
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Primary Examiner: Nozick; Bernard
Attorney, Agent or Firm: Merchant, Gould, Smith, Edell,
Welter & Schmidt
Parent Case Text
CROSS REFERENCE
This patent application is a Divisional application of U.S. Ser.
No. 195,873, filed Oct. 10, 1980, and entitled `Self-Cleaning
Pulsed Air Cleaner` now U.S. Pat. No. 4,331,459, of which there is
a copending Continuation-in-part application, U.S. Ser. No. 242,999
filed Mar. 12, 1981 for `Self-Cleaning Pulsed Air Cleaner`.
Claims
What is claimed is:
1. The method of removing particles of solid matter from air which
comprises:
(a) supplying a stream of uncleaned air to one end of a filter
having adjacent sections defining chambers with a motion having a
generally horizontal component parallel to the surface of the
filter, so that the particles are initially collected on a surface
of said filter and the air passes through the filter;
(b) repeatedly and sequentially supplying a reverse air pulsed to
each of the chambers in a sequence from the uppermost section to
the lowermost section dislodging the particles briefly from the
surface of each filter section to enable them to migrate therealong
toward the adjacent section and downstream toward a scavenge outlet
located toward the remaining end of the filter; and
(c) withdrawing at said scavenge outlet said air carrying the
migrated particles.
2. A cleaner for removing particulate matter from air comprising,
in combination:
(a) a housing having first and second spaced opposite ends;
(b) at least one filter assembly in said housing extending between
said ends, said filter assembly comprising filter means permeable
to air but not permeable to particulate matter, and including
filter means having an opening interior space defined therein, said
space extending toward said second end of said housing; and
vertically spaced generally horizontal partitions dividing said
space into plurality of vertically spaced chambers;
(c) means mounting said filter means in said housing so as to
divide said housing into a first portion on one side of said filter
assembly and a second portion on an opposite side of said filter
assembly;
(d) means providing a path for a stream of air through said filter
assembly, including:
(i) inlet means in said housing near said first end thereof for
admitting raw air to said first portion of said housing, and
(ii) outlet means near said second end of said housing for enabling
egress of clean air from said second portion of said housing, so
that particulate airborne matter is initially collected on said
filter means;
(e) scavenging means in said housing generally opposite said inlet
means for removing from said first portion of said housing
particulate matter separated from the raw air by said filter means;
and
(f) a plurality of cleaning means associated with each filter
assembly for intermittently directing pulses of clean air towards
said filter assembly from said second portion of said housing to
momentarily dislodge said particulate matter collected thereon,
said cleaning means being actuatable so that said pulses are
directed sequentially into said filter chambers generally in the
direction of air flow from said inlet means to said outlet means
whereby said dislodged matter may migrate generally in the
direction of said air flow toward said scavenging means. .Iadd.
3. The method of removing particles of solid matter from air which
comprises:
(a) supplying a stream of uncleaned air to one end of a filter
assembly having flat filter elements defining chambers, with a
motion having a generally horizontal component parallel to the
surface of the filter elements so that particles are initially
collected on said surfaces and the air passes through the filter
elements;
(b) supplying reverse air pulses to said chambers in a repeating
cycle to dislodge the particles briefly from the surface of each
adjacent filter element to enable them to migrate therealong with
the air stream in a downstream direction toward a scavenge outlet
located at the remaining end of the filter assembly; and
(c) continuously withdrawing at said scavenge outlet said air
carrying the migrated particles. .Iaddend. .Iadd.4. A cleaner for
removing particlate matter from air comprising, in combination:
(a) a housing having first and second spaced opposite ends;
(b) at least one filter assembly in said housing extending between
said ends, said filter assembly comprising vertically oriented,
flat filter members permeable to air but not permeable to
particulate material, said filter members having a tapering space
defined between adjoining surfaces of said filter members opening
toward said second end of said housing; and vertically spaced
generally horizontal partitions dividing said space into a
plurality of vertically spaced chambers;
(c) means mounting said filter assembly in said housing so as to
divide said housing into a first portion on one side of said filter
assembly and a second portion on an opposite side of said filter
assembly;
(d) means providing a path for a stream of air through said filter
assembly with a motion having a component parallel to the surfaces
of said filter members, including:
(i) inlet means in said housing at said first end thereof for
admitting raw air to said first portion of said housing, and
(ii) outlet means at said second end of said housing for enabling
egress of clean air from said second portion of said housing, so
that particulate airborne matter is initially collected on said
filter means;
(e) a plurality of cleaning means associated with each filter
assembly for intermittently directing pulses of clean air towards
said filter assembly from said second portion of said housing
sequentially into said chambers to momentarily dislodge said
particulate matter collected on said filter elements so that said
dislodged matter may migrate generally in the direction of said air
flow toward an end of said filter assembly opposite said inlet
means; and
(f) scavenging means in said housing at said end of said filter
assembly for removing particulate matter separated from the raw
air. .Iaddend.
Description
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. 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 collects 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 frequent 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 shaking or by reverse
air jet pulsing. The latter cleaning procedure is successful, when
the filter medium is pleated paper, in releasing the particulate
matter from the medium, 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
The present invention comprises 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.
Various advantages and features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
hereto and forming a part hereof. However, for a better
understanding of the invention, its advantages, and objects
attained by its use, reference should be had to the drawing which
forms a further part hereof, and to the accompanying descriptive
matter, in which there are illustrated and described certain
preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing, wherein like reference numerals refer to like
elements throughout the several views,
FIG. 1 is a plan view of an air cleaner according to the invention,
parts being broken away;
FIG. 2 is a view generally in vertical section looking along the
line 2--2 of FIG. 1; FIG. 3 is a view in perspective of a filter
assembly used in the air cleaner of FIGS. 1 and 2;
FIG. 4 is a view in horizontal section looking along the line 4--4
of FIG. 3;
FIG. 5 is a somewhat schematic view in section of a second
embodiment of the invention; and
FIG. 6 is a schematic wiring diagram.
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the invention shown in FIGS. 1 and 2 comprises an
airtight housing 20 having a removable or hinged top 21, a bottom
22, opposite sides 23 and 24, opposite ends 25 and 26, and a
vertical partition 27 which divides 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 FIG. 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 FIGS.
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 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 cement. The pleats of the filter medium
run vertically, 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 FIGS. 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
to 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 valve 78. The valves
connect with nozzles 80, 81, and 82 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 FIG. 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 filter 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 filters, 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 FIG. 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 repeating 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 being removed.
Operation
In operation top 20 is opened and a plurality of clean 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 connected 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 chambers 60 of
the filter assemblies, interrupting the flow of air inwards through
the filters and momentarily discharging dirt particles from the
outer surfaces of the filters. 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 gravity 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. 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 dimensions will naturally vary with the size of
the installation: 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 FIG. 6 to comprise a housing 100 divided by a
partition 101 into a lower, larger chamber 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 supplied as described above.
Filter assemblies such as assembly 110 are supported on and sealed
to partition 101, and may be as shown in FIGS. 3 and 4.
Housing 100 is provided with a vertical partition 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
decribed earlier. Particles of dust initially collecting on the
surfaces of the filters, are momentarily released by the cleaning
jets, and migrate across the filter surfaces. 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 negative
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
fashion.
From the above it will be evident that I have invented an air
cleaner in which particulate matter initially collected on a filter
surface is enabled and caused to migrate across the filter surface
to a scavenging location, as a result of operation of cleaning
pulses, from which location it may be removed. Operation of the
system for indefinite periods without interruption for removal of
collected dirt is accordingly enabled.
Numerous characteristics and advantages of my invention have been
set forth in the foregoing description together with details of the
structure and function of the invention, and the noval 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 arrangement of parts,
within the principle of the invention, to the full extent indicated
by the broad general meaning of the terms in which the appended
claims are expressed.
* * * * *