Note: Descriptions are shown in the official language in which they were submitted.
10477~1
COLLECTOR SYSTEM IN A VACUUM SWEEPER CIRCUIT
The present invention relates to vacuum sweepers, and
more particularly to the collector systems within heavy duty
vacuum sweepers used for industrial purposes.
A primary object of the invention is to provide a vacu- -
um sweeper which is especially useful in p~cking up loose parti-
cles such as gravel from surfaces whereon a considerable amount
of fine dust has collected and which includes a novel and im- -
proved collector system in the vacuum circuit which is capable
of effectively retaining both the particles and the dust. As
such, the ineention will be called "A Collector System in a Vacu-
um Sweeper Circuit".
While the present invention is ideally suited for many
types of industrial uses where it is necessary to remove both
particles and dust from the surfaces being swept, the paramount
commercial use for the invention resides in sweeping commercial,
asphalt-coated types of flat roofs so that they may be repaired.
Such roofs, mostly on commercial buildings, are built according -
to a standard procedure where layers of asphalt saturated felt
are laid upon the roof surface and cemented together with a coat-
ing of hot-mop aspha`lt or tar with the top layer being a compara-
tively thick coating of hot-mop asphalt or tar covered with a
layer of small generally uniform rocks such as pea gravel or the
like. ~-le rocks forming the layer of gravel embed themselves into
the asphalt to protect the roof covering, the asphalt and the
feIt sheets therebelow, against physical damage and weather dete-
rioration especially by sunlight.
A good average life for such a roof may be approximately
ten years, at which time it must be repaired and rehabilitated.
The repair procedures which have become quite standardized include
removing the gravel cover, which is mostly loosened from the
asphalt coating by that time. Also, it is necessary to remove the
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dust and dirt which has accumulated on the roof, over its life.
The dust and dirt is deposited from an airborne condition and it
can become quite a problem. The common procedure for removing
the rock and dust is by sweeping the roof with heavy brooms.
This is a very onerous, slow chore where the workmen will get
very dirty, especially on a hot day, and they are usually re-
quired to wear masks because of the large amounts of fine dust
which are stirred up by the sweeping and dumping the gravel from
the roof to a truck. The dust is, also, almost always objection-
abIe to other people in the vicinity of the building.
There is a real and definite need for improved systemsfor cleaning the gravel and dust accumulations from the asphalt-
coated type of roof such as is commonly found in most industrial
buildings throughout the country~ The present invention was con-
eeived and deveIoped with such a need in view, and this invention
comprises, in essence, a large, heavy duty vacuum sweeper having
within its vacuum circuit a novel and improved collector system,
which combines a receiving and transportation bin, a cyclone and
a filter in an arrangement which will effectively and efficiently
direct the flow of air through the vacuum sweeper to sequentially
deposit gravel and dust and thereafter, filter from the air all
very fine particles and dust not deposited to provide a compara-
tively clean air discharge from the system.
It follows that another object of the invention is to
provide a novel and improved collector system for a vacuum sweeper
which is especially adapted for cleaning gravel and dust from an
asphalt-coated type roof surface preliminary to repairing the
surface.
Another object of the invention is to provide a novel
and improved collector system in a vacuum sweeper circuit includ-
ing a container unit which will collect particles and dust in an
efficient manner and which can be carried upon a dump truck or a
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like vehicle to provide for an easy mode of disposing of the par-
ticles and dust collected in the unit.
Yet another object of the invention is to provide a
collector system for a vacuum sweeper which will more effectively
retain both large particles, such as gravel, and fine particles,
such as dust, in a single disposable container by compartmenting
the container to separate the different sizes of particles and
prevent recirculation of dust particles.
Another object of the invention is to provide in a col-
lector system for a vacuum sweeper, a novel and improved arrange- -
ment for mechanically dropping large particles such as gravel and
also, most of the finer particles of dust to such an extent that
a final filter may be used to completely clean the air before
permitting it to discharge to the atmosphere and this final filter
can operate for substantial time periods without clogging and
requiring cleaning.
Yet another object of the invention is to provide in
comb-nation with a collector system for a vacuum sweeper, a
simple, efficient, easily maintained, final filter to prevent very
small particles from being discharged into the air~
Other objects of the invention are to provide in a
collector system for a vacuum sweeper a simple, economical, ef-
fective, easily maintained, rugged and durable system~ -
With the foregoing and other objects in view, my pre- -
sent invention comprises certain constructions, combinations and
arrangements of parts and elements as hereinafter described,
defined in the appended claims and illustrated in preferred -
embodiments by the accompanying drawings in which:
Fig. 1 is a small scale, somewhat diagrammatic, isomet-
ric view of a vacuum sweeper being used for sweeping a roof hav-
ing the improved collector system in its circuit constructed ac-
cording to the inventign;
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1047711
; Fig. 2 is a side elevational view of the collector sys-
tem components of the vacuum sweeper shown at Fig. 1, but on an
; enlarged scale and with wall sections of the containers being
broken away to show arrangements and parts therewithin;
Fig. 3 is a sectional plan view of the primary collec-
tor bin as taken from the indicated line 3-3 at Fig. 2;
Fig. 4 is a fragmentary isometric view of the rear end
of this primary bin with the discharge gate being open;
Fig. 5 is a sectional elevational view as taken from
the indicated line 5-5 at Fig. 2;
Fig. 6 is a sectional plan view of the final filter sec-
tion of the system as taken from the indicated line 6-6 at Fig.
2, but on an enlarged scale;
Fig. 7 is a sectional view as taken from the indicated
' line 7-7 at Fig. 6, but on an enlarged scale;
~r Fig. 8 is a fragmentary isometric view of portions of
the two filter elements shown at Fig. 6, but on an enlarged scale;
and
Fig. 9 is a small scale, somewhat diagrammatic perspec-
tive view of a modified embodiment of a collector bin comparableto the unit illustrated at Figs. 1-8, but showing the same as
being mounted upon an elevated framework.
Referring more particularly to Figs. 1 to 8 of the
drawings, the apparatus for cleaning the gravel from the roof
of a building B, constructed according to the present invention,
is a vacuum sweeper having the several improved components of
the collector system in the sweeper circuit which consists of a
2, 3 or 4 inch line L having flexible portions and rigid portions
and is sufficiently long so that it may extend from a gravel and
dirt separating system to the deck of a building. Commencing at
a pickup head 20 which is used by an operator on the roof of the
building B, a first reach 21 of a flexible line L extends to a
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1047711
rock collecting container 22 of the collector system which is
conveniently carried upon a dump truck D. A second reach 23 of
the line extends from the rock collecting container 22 to a cy-
clone separator 24 which is adapted to drop dust into a special
compartment within the rock collecting container as hereinafter
described. A third reach 25 of the line extends from the cyclone
exhaust to a final filter 26 and a short fourth reach 27 of the
line from the filter terminates at a vacuum pump 28 (air blower
using the intake side for vacuum) and the discharge from this
vacuum pump is to the atmosphere. The vacuum pump 28 is driven
by a suitable engine indicated at 29, and to provide a convenient
portable apparatus, the final filter and the vacuum pump are car-
ried upon a trailer T which may be towed by the dump truck D when
moving from one location to another. -
It will be necessary to operate the dump truck carrying
the rock collecting container 22 independently of the filter 26
and vacuum pump 28 on the trailer, as when a load of gravel and
dust picked up from a roof must be transported to a disposal site
as hereinafter described. Accordingly, suitable disconnect
couplings 30 are provided on the first line reach 21, from the
container to the pickup head, and the third line reach 25, from
the container to the filter, to quickly disconnect these lines
from the truck so that the truck may travel independently of the
line 21 and the trailer T.
The first line reach 21 which extends to the pickup
head will be a flexible, lightweight hose of any suitable conven-
tional type which is commonly used with commercial vacuum clean-
ing operations and it is to be noted that this line reach may be
from 50 to 100 feet long, or such, so that it can be extended to
the roof of a building B several stories high. The pickup 20 at
the intake of this line will ordinarily include a rigid, light-
weight handle and a head formed of any suitable conventional type
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which will facilitate the picking up and movement of gravel and
dust into the line responsive to the inflow of air thereinto.
The rock collecting container 22 is formed as a box-
like structure proportioned to fit in the bed of a conventional
dump truck and this container is formed as an enclosed sheet
metal structure having a bottom 31, front end wall 32, side walls
33, a rear end wall 34 and a top 35. The container, made of sheet
metal, is suitably welded together as a gas-tight, unitary
structure and it may include reinforcement members, such as angles,
at its several walls to resist the crushing forces imposed upon
this structure by the air pressure differential between the out-
side and inside of the container when the vacuum sweeper is in
operation. Such angles or other reinforcemen~s across these
severàl walls are not shown in the drawing since they are con-
ventional in the construction of vacuum containers, and whether
or not they will be needed is a matter easily ascertained by a
skilled designer of the system.
The rear end wall 34 includes an opening 34' across its
bottom portion which is normally closed by a hinged discharge
gate 36. This gate may be opened to permit the contents of the
container to be discharged from it by tipping the dump truck
wherein thé container is mounted. The gate is pivoted by a hinge
37 along the bottom edge of the container and is normally held
closed by suitable latches 38 on the rear wall above the discharge
opening 34'.
Since the system will operate under a vacuum, it becomes
important to prevent air leaks as at the gate 36. Accordingly,
the opening 34' will be edged with a continuous strip seal 39, of
a suitable resilient material such as foam rubber. Not only will
this seal extend about the periphery of the opening, but also a
seal portion 40, bearing against the closed gate, will lie at the
edge of a partition wall which forms a compartment at one corner
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of the container as best illustrated at Fig. 4. This effectively
forms two separated containers when the gate is closed.
To complete the rock collecting container 22, a diag-
onally positioned partition 41 at a rear corner of the container
divides the container into a major compartment 42 wherein small
rocks and similar particles will be collected, and a minor, cor-
ner compartment 43 wherein dust will be collected, the cyclone 24
heretofore mentioned being located on the top of the container
directly over the minor-compartment to drop dust thereinto. It
is to be noted that with the minor compartment 43 being located
at a rear corner of the container, the discharge gate 36 will ~ -
also open this compartment as illustrated at Fig. 4 as well as
the major compartment 42, so that both gravel and large particles
in the major compartment, and dust in the minor compartment will
be discharged from the container at the same time.
The first and second reaches 21 and 23 of the vacuum ~-
line L and the cyclone separator 24 are located on the top 25 of-
the container 22. Accordingly, a first reach of the vacuum line
which extends from the intake end of the system at the pickup
head 20 to the container will drop into the major compartment 42,
preferably at the center of the container. The line 21 will be
connected to the top of the container by suitable flange 44 and
may terminate at the edge of the container top or extend a short
distance into the major compartment as at 21a at Fig. 2. With
this arrangement, with the air flow from the intake through the
first reach of the line and into the container, all of the rocks
and heavy particles picked up by the head 20 at the intake of the
vacuum system will be dropped into the container so that only
dust can be discharged from this major compartment of the con-
tainer through the second reach 23 of the line L and to the cy-
clone 24.
This second reach 23 of the vacuum line L extends from
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the top 35 of the container and to the cyclone separator~ The
line may be a lightweight, rigid tube or lightweight, flexible
conduity such as will be used for the first reach 21 of the line.
It will connect to the container top 35 by a suitable flange 45
and connect with an intake pipe stub of the cyclone separator by
a suitable coupling 46. By placing the end of this second reach
23 of the line and the cyclone at the top of the container, as
heretofore mentioned, the upward flow of air into the second
reach will prevent any large particles from moving into the cy-
clone.
The cyclone separator 24 is essentially a conventionalunit formed as an upright cylindrical structure with the lower
portion conically converging to connect with and drop dust removed
from the air stream into the bottom of the cyclone and into the
minor compartment 43. The intake 48 to this cyclone is tangen-
tially located near the top of the cylindrical wall to cause air
moving thereinto, from the line section 23, to swirl about the
wall of the cylinder to cause dust to move against this wall
through centrifugal action and thereafter drop to the bottom of
the conical section. The discharge from this cyclone is upwardly
through an axially centered tube 49 which turns and connects with
the third reach 25 of the line L as by a coupling 50.
With this cyclone all but the finest dust particles
will drop into the minor compartment 43 whenever the vacuum sys-
tem is in operation. It is to be noted that during operation
of the system, with the suction action taking place at the vacu-
um pump 28, there will be a head loss in the air line in addition
to the pressure drop required to attain a high velocity of air
flow through the line. Accordingly, the reduced pressure within
the cyclone separator will be accompanied by an expansion of the
air to the point where this rarified air will have a significant-
ly reduced viscosity, permitting even small dust particles to
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rapidly fall out of the swirling air flow within the cyclone.
The air flow from the cyclone and into the third reach
25 of the line L enters the~final filter 26, a cylindrical shell,
the line being connected to a stub 54 in the side, and near one
end, of the final filter by a coupling 55, as shown at Fig. 2.
The filter 26, a cylindrical chamber 26a, has its ends closed by
circular end plates 56 and 57. As illustrated at Fig. 6, these
end plates are bolted onto flanges 58 at each end of the cylin- -
drical body 26 of the filter and it is contemplated that the
bolts at one end of this flange can be easily removed to permit
the filter elements therewithin to be quickly changed. - -
In the unit illustrated, two cylindrical filter elements
59 are used, each element being formed as a cylindrical, tubular
member somewhat smaller in diameter than the body of the shell
of the filter 26a. The cylindrical walls of these filter elements
are formed of a suitable, rigid, porous material (paper over sup-
port screening~ which will withstand a moderate degree of com-
pressive forces. An inturned flange 60 is formed at one end of
the shell which is of a rigid material, while a resilient inturned
L-shaped coupling section 61 is formed at the other end of the
sheIl which is adapted to abut-against the inturned flange of
the other filter eIement as shown at Fig~ 8 or against a wall of
the filter flange 57.
The two filter elements 59 are concentrically mounted
within the cylindrical filter chamber 26, in tandem, with the
end of oneelement abutting against the end plate 57. The other
end of the filters is held in place by a pressure plate 62 and
this end is located adjacent to the connection of the third reach
25 of the line L, at the stub 54. Air entering the filter must
flow past this pressure plate 62 and accordingly, it is formed as
a regular polygon, as shown at Fig. 7, to bypass air about its
periphery and at the same time, automatically center itself in
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the cylindrical shell 26. It is to be noted that this plate may
be formed with scallops or other configurations which will func-
tion in a like manner. This pressure plate is held against the
filters by a set screw 63 axially threaded into the end plate 56
to bear against the pressure plate 62 as best illustrated at Fig.
6. To complete this filter, an axially centered pipe stub 64 is
located at the opposite end plate 57 to connect with the fourth
reach 27 of the line L which, in turn, connects with the vacuum
pump 28.
The operation of this apparatus is manifest from the
foregoing description. When the vacuum sweeper is in operation,
a flow of air into the pickup head 20, through the first reach of
the line L, discharges into the major compartment of the container
22. This compartment functions as an enlargement in the passage-
way to reduce the velocity of the airflow and to drop all large
particles picked up by flow through the line. The flow from the
compartment into the second reach 23 of the line and to the cy-
clone separator will carry only light weight dust, most of which
is dropped out of the system by the cyclone separator 24 into
the minor compartment of the container 22 while the air cleaned
of all but the finest particles of dust will flow to and through
the filter eIements 59 of the final filter 26 and then be dis-
charged to the atmosphere by the pump 28. Pr~ferably, the air
pump is a high volume unit arranged so that on a two-inch line it
pulls at least about 800 scfm on an open inlet~ This insures a
complete pickup of the gravel. The pump must be increased in
size, of course, as the lines are increased in size so as to pro-
vide an equivalent air flow through the lines~ The engines for
driving the air pump must, of course, be adequate to drive the
pump at the optimum rpm, even at a close off condition on the
line. The engine may advantageously be a gasoline engine of suf-
ficient horsepower, providing the motivating power independently
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of the building or its services. Alternatively, where electric
power is available, a sufficiently high horsepower motor to run
the air pump may be used.
The basic arrangement shown in Figs~ 1-8, may, also, be
used in conjunction with structural arrangements other than that
hereinabove described and a modified embodiment of the invention
to illustrate this is shown at Fig. 9 wherein the compartment 22'
is formed as a closed, hopper-like structure mounted upon a struc-
tural standard 70 in an arrangement which permits a dump truck or
the like to move underneath the hopper to receive rocks and dust
accumulated in this hopper. As such, the discharge gate 36' of
the hopper is preferably located at the bottom of the unit. How-
ever, the other compartments within and connecting to this hopper
are essentially the same as heretofore described. A partition
wall 41' divides the interior of the hopper into a major compart- ~-
ment 42' wherein rocks are dropped and a minor compartment 43'
wherein the dust is dropped. The line reaches, as indicated,
will include a first reach 21' whereon the pickup line is con-
nected; a second reach 23' extending from the major compartment
42' to a cyclone 24' and a third reach 25' which extends to the
final filter as hereinbefore described.
I have now described my invention in considerable detail.
However, it is obvious that others skilled in the art can build
and devise alternate and equivalent constructions which are
nevertheless within the spirit and scope of my invention. Hence,
I desire that my protection be limited not by the constructions
illustrated and described, but only by the proper scope of the
appended claims.
