Note: Descriptions are shown in the official language in which they were submitted.
~ 2
In many industries, such as the plastics industry, it is
common practice to transport finely divided, granular or pulverant
material from one or more storage bins, through one or more feed-
lines, having a free end embedded in or otherwise in communication
with the respective materials to be transported, to a material
receiving hopper of a loader by creating a vacuum in the loader.
The resultant airflow occurring due to the vacuum is through the
material and the one or more feedlines entrains the material in the
airstream flowing to the receiving loader. The airstream carrying
the material entrained therein enters the loader and the entrained
material is deposited in the loader material receiving hopper while
the air is withdrawn from the loader by the vacuum pump. After the
receiving hopper has been loaded and the vacuum discontinued the
material deposited therein is subsequently discharged into a material
receiving compartment of any suitable apparatus, for example a
material processor.
In material transporting systems such as the type described
above, large amounts of lightweight fines frequently exist in the
material being transported. When these fines reach the loader a
portion will not follow the normal material flow path to the receiving
hopper of the loader because of the light weight thereof and would
tend to remain in the air withdrawn from the loader by the vacuum
pump. Should the fines flow from the loader through the exit conduits
to the vacuum pump, substantial operating problems, such as poor pump
performance may result. Furthermore, if the fines actually flow into
the vacuum pump, a high probability of pump damage will result.
-2-
~ 62
To alleviate the above described problems due to lightweight
fines, many modern primary receiving hoppers utilized a cyclonic
separation arrangement within ~he receiving hoppers in combination
with a filter media such as a flat cloth disc filter, a cartridge
filter, cloth bag filter or a metal screen filter adjacent the
vacuum connection to the receiving hopper to prevent a substantial
portion of the continuously entrained fines in the airstream from
flowing to the vacuum pump. Furthermore a recent advance in such
transporting systems, as is illustrated in U.S. Patent Application
Serial No. 930,715, filed August 3, 1978 and assigned to the same
assignee as is this invention, provides an even more significant
cyclonic type separation which, in many instances, alleviates the
necessity of a filter adjacent the vacuum connection to the receiving
hopper. Nevertheless in all instances of such transporting systems,
the systems necessarily included a passive filter, such as a cloth
disc filter or metal screen, which was disposed in the vacuum line
adjacent the vacuum pump.
With the utilization of passive filters such as described
adjacent the loaders and/or vacuum pump, certain inherent problems
result, for example:
1. Reduced material flow rate due to gradually increasing
pressure drops across the filters as they become increasingly
clogged with fines.
2. Rough material flow, surging and line plugging due to
dirty filters which interfere with air flow.
~ 2
3. Substantial maintenance problems and expense
necessitated by frequent requirements of filter cleaning or re-
placement. In this regard, it is noted that with a typical
plastics transporting device which transports five hundred pounds
of pulverant per hour, it is not unusual to require filter main-
tenance every eight hours.
4. Damaged vacuum pumps caused by incorrectly installed
or missing filters.
5. In those systems which include filters adjacent the
loader-vacuum line connection, increased maintenance ris~ resulting
from the primary filter location. In these instances, because of
the large amount of fines which are separated from the normal
material flow, the primary filter often is located within the
primary material receiver, eight to twelve f~et above the floor
level. Thus maintenance persons must climb to this upper location
in order to change or clean the filter.
The present invention includes a vacuum material trans-
porting system having a cyclonic dust collecting device disposed
in the vacuum line intermediate the loaders and the vacuum pump.
The dust collection device is located at ground level and further
includes means for selectively unloading the collected fines without
significantly interrupting the operating cycle of the transportation
system. Furthermore, the dust collecting device of this invention
includes means for automatically recycling the collected fines to
the primary feed line of the pneumatic transportation system. Thus,
the present invention greatly alleviates the above mentioned problems
inherent with prior vacuum material transporting systems. Specifically,
:
because of the significant degree of downstream removal of
entrained lightweight fines from the flowing airstream, coupled
with the selec-ted unloading of the collected fines wi-thout
affecting the operating cyc]e of the transportation system:
maintenance of the final filter adjacent the vacuum pump is
substantially reduced; filters at the loader vacuum line
juncture can be dispensed with in many instances, particularly
if the efficient separation arrangement of U.S. Patent
4,200,415 issued 29, April 1980 is utilized, material waste,
downtime and manpower requirements will be reduced substantially;
and generally a more efficient and smooth material flow and
operation of the vacuum pump will result.
Accordingly, it is one object of this invention to
provide a new and improved vacuum material transporting system
for granular or pulverant material having improved dust collecting
means for separating the lightweight fines associated with the
transported materials at a location downstream from the
loaders and thereafter selectively discharging the fines from the
dust collecting means without substantially affecting the
operating cycle of the transporting system.
Another object of this invention is to provide a
vacuum material transporting system wherein -the dust collecting
means is located adjacent a floor level location.
A still further object of this invention is to provide
a vacuum material transporting system having improved dust
collecting means which selectively reintroduces collected fines
to the main material flow.
[The term "dust" as used in the specification includes
fine and extremely fine particles.]
csm/'~ ~ 5 ~
~ 2
These and other objects of this invention will become more
readily apparent upon a reading of the following description and
drawings in which:
Fig. 1 is a schematic representation of a vacuum material
transporting system which utilizes a dust collecting means and
method of the present invention;
Fig. 2 is a partial sectional and partial schematic view
of the dust collecting means of a vacuum material transporting
system of the present invention as such dust collecting means is
assembled in an automatic unload - reload mode of operation;
Fig. 3 is a partial sectional and partial schematic ~iew
of the dust collecting means of Fig. 2 with a manual or semi-
automatic unloading ixture thereon rather than the automatic unload
and reload fixture illustrated in Fig. 2 and which also includes
a floor stand assembly for supporting the dust collecting means.
Fig. 4 is a schematic plan view further illustrating-the
floor stand assembly shown in Fig. 3.
Fig. 1 is a schematic representation of a material trans-
porting system 10 constructed in accordance with the principles
of the present invention and of the type utilized in the vacuum
transportation of finely divided, granular or pulverant material
and, as illustrated, is for use in the plastics processing industry.
System 10 comprises: an upstream material source 12; one
or a plurality of material loader assemblies 14 which are located
downstream of the source 12 (only one assembIy 14 being shown);
and a primary material transporting conduit 16 which communicates
between the source 12 and the material receiver 14. A suitable
vacuum pump 20 communicates with loader assembly 14 by means of
conduit 18 to provide the necessary suction to create an airflow
to transport material to be processed from the source 12 through
the conduit 16 to the loader assemblies 14. In the transporting
system 10 of Fig. 1, the material which is transported to loader
assemblies 14 is then discharged therefrom for subsequent processing
or storage, such as into plastic processing machines 22 or into a
suitable storage hopper (not shown).
The system 10 of the present invention additionally in-
cludes a dust collecting means 24 which is positioned adjacent a
ground level elevation and which is in communication with suction
conduit 18 at a location downstream of the loader assemblies 14
and upstream of the vacuum pump 20. Dust collecting means 24 is
included in system 10 for separating a substantial portion of the
dust or lightweight fines which may be carried by the airstream
exiting from loader assemblies 14. This separation is accomplished
by means 24 in any suitable manner, such as by cyclonic action,
and means 24 includes provisions for the accumulation and the
selective or automatic discharge of the accumulated fines without
substantially affecting the operating cycle of the system 10. If
desired, a ground level final filter 25 may be disposed within
suction conduit 18 intermediate the dust collecting means 24 and
the vacuum pump 20 to assure that any small amount of lightweight
fines which are not collected by means 24 do not reach the vacuum
pump 20.
S 2
Inasmuch as the invention herein is primarily in the
utilization and location of dust collecting means 24 in a
transporting system such as system 10 and further, that the
general operation and configuration of vacuum transporting systems
and their respective component parts are well known in the art,
a detailed description of such well known operation and components
of system 10 are not necessary to one skilled in the art for a
full understanding of the invention herein. For example: a
specific description of a material loader assembly, such as
assembly 14, appears in U.S. Patent 4,200,415 which issued 29,
April 1980 and assigned to the same assignee as is this invention;
and descriptions of the loader discharge valve assemblies appear
in U.S. Patent Nos. 3,273,943 and 3,635,377.
Dust collector means 24 is shown inthe drawings with a
plurality of selectively interchangeable operating components.
In particular, and as will be described in detail hereinafter:
the arrangement of dust collector means 24 in Figs. 1 and 2
provides for an automatic recycling of collected lightweight
fines to the primary material transporting conduit 16; and the
arrangement of means 24 as illustrated in Fig. 3 provides for
a manual or semi-automatic unloading of the collected fines.
Dust collector means 24 is of any suitable construction
so long as it meets the following criteria:
csm/~,~
~ 3 ~
1. Provides a substantial separation of carry-over
lightweight fines from the flow of air passing therethrough;
2. Does not provide a significant resistance to the
air flow through suction conduit 18 from the material loader
assemblies 14 to the vacuum pump 16;
3. May be readily emptied of accumulated fines without
a substantial effect on the operating cycle of the system 10; and
4. Provides a large area for accumulating fines or, in
the alternative, includes means for automatically or sequentially
discharging the accumulated fines to an exterior location.
As shown in Fig. 2, dust collecting means 24 includes a
separating portion 26 in communication with suction conduit 18.
Suction air which includes lightweight fines suspended therein
enters separating portion 26 from conduit 18 whereupon it will be
subjec~ed to suitable cyclonic and/or tortuous flow through a
plurality of cyclone tubes 27 which results in a significant portion
of the suspended fines being separated from the air flow. The
"cleansed" airflow then enters a filter portion 28 of collecting
means 24 which is located upwardly adjacent portion 26. Suitable
filter media, such as a filter cartridge 29, is included within
filter portion 28 to filter out any small amount of suspended fines
which may have carried over from separating portion 26. The clean
suction air then flows from filter portion 28 back into the down-
stream spaced portion of conduit 18 and therefrom to the vacuum
pump 20. If desired, a suitable popper type valve 30 may be
positioned on portion 28 adjacent the connection of conduit 18
11 ~1 &~62
thereto to sequentially provide a sudden pressure differential to
dislodge accumulated fines from the filter cartridge 29 within
portion 28. Final filter 25 is disposed in conduit 18 intermediate
collecting means 24 and vacuum pump 20 to provide a still further
safeguard to prevent lightweight dust from entering pump 20. I~
is anticipated that the amount of dust carried over to final filter
25 will be insignificant, thus final filter 25 will only be rarely
replaced or cleaned.
Dust collecting means 24 additionally includes a support
and transition portion 32 downwardly adjacent separating portion
26. Portion 32 includes: a hollow generally cylindrical main
body section 33 which sealingly supports portion 26 adjacent the
upper end thereof; and a support assembly 34 which extends around
a portion of body section 33 and is cooperable with a floor support
100 for the releasable support of dust collecting means 24 in a
manner as will be described in detail hereinafter.
A plurality (only one being shown) of circumferentially
spaced over-the-center latch assemblies 38 are carried by main body
section 33 adjacent the lower end thereof. As is illustrated in
2~ the drawings, latch assemblies 38 are operable to selectively support
a product receiver assembly 40 for the automatic or semi-automatic
discharge of collected fines from dust collecting means 24, or a
product receiving canister 80 (Fig. 3) for the accumulation and
subsequent manual removal of fines separated from the flowing air-
stream by dust collecting means 24.
-10-
Referring to Figs, 1 and 2, dust collecting means 24
supports the product receiver assembly 40 adjacent the lower end
of main body section 33 by means of latch assPmblies 38. Product
receiver assembly 40 comprises a hollow inverted generally frusto
conical body portion 44 having a circumferentially and radially
outwardly extending flange 46 adjacent the upper end thereof.
Flange 46 includes a circumferentially and upwardly extending lip
portion 48 adjacent the outer periphery thereof which is structured
in such a manner to cooperate with the adjacent lower periphery of
body section 33, in conjunction with flange 46, to provide a
peripheral sealing area between section 33 and body portion 44
when latch assemblies 38 support the product receiver assembly 40.
A conical valve assembly 50 is provided adjacent the lower discharge
opening 52 of body portion 44. Valve assembly 50 is selectively
actuatable, such as by an air operable valve schematically shown
at 54, to close off and uncover opening 52 to control the discharge
of accumulated fines therefrom. Inasmuch as the specific configura-
tion and operation of discharge valve assembly 50 is generally well
known in the art and has been previously shown and described in
various prior art patents, such as United States Patent Nos. 3,273,943
and 3,635,377, further description thereof is not necessary for an
understanding of this invention by one skilled in the art.
Product receiver assembly 40 additionally includes a
radially outwardly extending flange 56 upwardly adjacent the lower
end thereof. Flange 56 includes a circumferentially and down~ardly
extending lip portion 58 adjacent the outer periphery thereof which
is structured in such a manner to cooperate with adjacent portions
-11-
~3~
of an automatic reloader assembly 60, in conjunction with flange 56,
to provide a peripheral sealing area between receiver assembly 40
and loader assembly 60 when the assembly 60 is supported by assem-
bly 40.
Reloader assembly 60 comprises an upper cylindrical body
portion 62 and an inverted generally frusto conical lower body
portion 64 which extends coaxially downwardly from portion 62.
Portion 62 includes a plurality (only one being shown) of circum-
ferentially spaced upwardly extending over-the-center latch
assemblies 66 adjacent the upper end thereof which are operable to
cooperate with flange 56 for the selective support of reloader
assembly 60 by the product receiver assembly 40. The lower discharge
opening 68 of body portion 64 is in open communication with a
transition stub conduit 70. Stub conduit 70 communicates at one
end thereof with a reloading conduit 72 which, as shown, communicates
between conduit 70 and an upstream portion of the primary material
transportint conduit 16. The end of stub conduit 70 which is in
communication with lower discharge opening 68 is normally closed
to atmosphere and is selectively opened to atmosphere by any suitable
~0 valve means, for example an electrically energizable valve which
is schematically illustrated in Fig. 2 at 74. A suitable control,
such as is schematically shown at control box 76, is provided for
the selective control of valve 74. As shown valve 74 is carried by
reloader assembly 60 adjacent body por~ion 62 and when it is opened
to atmosphere, the interior periphery of assembly 70, including
stub conduit 70, will be open to atmosphere.
-12-
With a configuration as described above and with the
understanding that suitable means are provided for electrical
signaling and resultant operations throughout the material trans-
porting system 10, one sequence of operation of one cycle of a
system 10 of this invention when an automatic accumulation of
fines and sequential automatic recirculation thereof by the dust
collecting means 24 is desired, is as follows:
1. Vacuum pump 20 is energized for a first time period
to cause material to be processed to flow through the primary
material transporting conduit 16 to load the material loader
assemblies 14 for the subsequent sequential discharge therefrom
to the processing machines 22.
2. During the first time period the conical valve
assembly 50 is energized to close off the lower discharge opening
52 thus providing that the lightweight fines separated from the
suction airstream flowing through dust collecting means 24 will be
accumulated within product receiver assembly 40.
3. During a first portion of the first time period, the
valve 74 is energized to open stub conduit 70 to atmosphere. This
will result in the accumulated lightweight fines which have been
previously discharged from receiver assembly 40 to the reloader
assembly 60 being drawn therefrom by suction through stub conduit
70, through the reloading conduit 72 and recirculated with the main
material flow at the juncture of reloading conduit 72 with the
primary material transporting conduit 16.
-13-
~ 2
4. Vacuum pump 20 is de-energized for a second time
period thereby resulting in a cessation of flow of material to be
processed through the primary material conduit 16.
5. During the second time period the conical valve
assembly is also de-energized thus resulting in lower discharge
opening 52 being open to reloader assembly 60 and the lightweight
fines which have accumulated within receiver assembly 40 will
flow by gravity into assembly 60.
6. During a second portion of the first time period
and continuing during the second time period, for example a total
elapsed time of 5 to 10 seconds, the valve 74 is de-energized thus
resulting in stub conduit 70 being closed to atmosphere.
It is understood that items 1 through 6 above define one
complete preferred cycle of a dust collecting means which includes
a product receiver assembly 40 and an automatic reloader assembly
60 and which separates lightweight fines from the flowing air-
stream at a ground level location and thereafter automatically
reintroduces the separated fines to the main material stream. It
is to be further understood that, depe~ding upon conditions and/or
equipment capacity, variations to the cycle described may be equally
acceptable or preferred. For example one such variable cycle would
be identical to items 1 through 6 described above with the exception
that the sequencing of items 2 and 5 would be modified somewhat
such that valve assembly 50 would close off opening 52 only during
the first portion of the first time period. In this alternative
cycle, valve assembly 50 would be de-energized at the beginning of
-14-
the second portion of -the first time period such -that receiver
assembly 40 will be in open communication with reloader 60 during
the second portion of the first time period as well as during the
second time period.
A still further variance to an automatic load and unload
sequence described in items 1 through 6 discussed above would be
to have conical valve 50 energized to close off the lower
discharge opening 52 only during a middle portion of every other
first time period. In the first and last portions of such a
first time period as well as during the intermittent fi`rst time
period and the adjacent second time periods the conical valve 50
would;be deenergized thus opening discharge opening 52 into
communication with reloader assembly 60. In such an alternative
sequence, the sequencing of valve 74 will be identical that of
valve 50 to provide that when opening 52 is uncovered,
energization of valve 74 will cause stub conduit 70 to be open
to atmosphere. This latter variance will result in a longer
length of time for separated lightweight fines to accumulate
within the product receiver assembly 40 and a significantly
shorter time period of operative communication between reloader
aSsembly 60 and the primary material transporting conduit 16.
Thus the variance described in this paragraph would more likely
be desirable in those instances when the upstream separatlon of
lightweight fines is relatively efficient (i.e. when using
material loader assemblies 14 such as are described in U.S.
Patent 4,200,415 issued 29, April 1980). If such an efficient
c sm/l,~
1! ~1 6~2
upstream separator was not utilized the brief communication of
reloader assembly 60 with conduit 16 may result in an undesirable
material surge.
It is to be noted that dust collecting means 24 may also
be utilized in a "semi-automatic" mode. In this variation only
the product receiver assembly 40 would be supported by dust collect-
ing means 24. A reloader assembly 60 fixture would not be included.
Opening 52 of assembly 40 can be arranged to selectively communi-
cate with any suitable material repository, for example a bin
(not shown). In such an alternative arrangement conical valve assem-
bly 50 could be sequenced in any desired manner; for example, a
timing arrangement, an electrical interlock arrangement, or through
energization from a signal resulting from a sensed material level
within receiver assembly 46.
Fig. 3 illustrates a manual unloading mode of the dust
collecting means 24. In this embodiment dust collecting support
and transition portion 32 supports a product receiving cannister
80 adjacent the lower end of main body section 33 by means of the
lat,ch assemblies 38. Product receiving cannister 80 comprises a
hollow generally cylindrical main body portion 82 having a lower
transversely extending end wall 84 and a circumferentially and
radially outwardly extending flange 86 adjacent the upper end
thereof. Flange 86 includes a circumferentially and upwardly ex-
tending flange 88 adjacent the outer periphery thereof which is
structured in such a manner to cooperate with the adjacent lower
periphery of body section 33 to provide a peripheral sealing area
~16-
1 ~ & ~
between section 33 and body portion 82 when latch assemblies 38 sup-
port the product receiving cannister 80. Body portion 82 additionally
includes a diametrically opposed pair of handles 90 thereon to
facilitate in the handling of cannister 80 when it is being manually
emptied.
With the arrangement illustrated in Fig. 3, the dust
collecting means 24 automatically separates the lightweight fines
from the flowing airstream and such separated fines drop by gravity
into cannister 80 which provides a large volume to hold the
accumulated fines. When it is desired to empty cannister 80, latch
assemblies 38 are easily released.
Figs. 3 and 4 additionally illustrate the cooperation of
support assembly 34 and floor support 100 in supporting the dust
collecting means 24 upwardly adjacent a ground level elevation.
As shown support assembly 34 comprises: an arcuate portion 102
rigidly secured, such as by welding, to an adjacent peripheral
portion of section 32; and a pair of arcuately spaced angle portions
104 having the long legs secured to respective arcuate ends of
portion 102 and ex~ending outwardly therefrom. ~ith such an arrange-
ment the free legs of angle portions may be releasably secured,such as by bolts 106 or the like, to a wall bracket or as shown
are releasably secured to floor support 100.
Floor support 100 includes a pair of transversely spaced
generally "L" shaped weldments 108 wherein the vertically extending
angle leg 110 has a respective free leg of an adjacent angle portion
104 releasably secured thereto and the horizontally extending angle
& ~ 2
leg 112 engages the ground surface downwardly adjacent the dust
collecting means 24. A knee brace 114 extends at an angle between
legs 110 and 112 and, if desired, struts (not shown) which extend
transversely between weldments 108 may be included to unitize and
add rigidity to support 100.
The embodiments described herein are the presently pre-
ferred embodiment of a vacuum material transporting system 10 of
the present invention; however, it is understood that variouæ
modifications may be made to the embodiments described herein by
~0 those skilled in the art without departing from the scope of the
invention as is defined by the claims set forth hereinafter~ For
example the sequencing of operation of the system 10 may be altered
to suit conditions of operation as well as various types of material
being transported; means to sense the quantity of accumulated light-
weight fines within receiver assembly 40 may be included; support
arrangements, other than assembly 34.and floor support 100 are
contemplated; and the like.
-18-
