Note: Descriptions are shown in the official language in which they were submitted.
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VACUUM-EXCAVATION APPARATUS
TECHNICAL FIELD
This disclosure generally relates to excavation. In particular, the disclosure
relates to an apparatus for vacuum-excavation.
BACKGROUND
Vacuum excavation uses pressurized streams of fluids to dig a hole, a pit, a
trench or a trough by loosening debris material such as soil, rocks and other
materials.
The loosened debris-materials are then pneumatically collected and removed by
a
vacuum system. Vacuum excavation can expose buried facilities without the risk
of
damage that may arise by digging with shovels or other heavy equipment.
Typically, vacuum-excavation apparatuses are transported upon large vehicles,
such as trucks. The trucks can carry liquid-pressurization or pneumatic
equipment,
vacuum equipment and large tanks for containing the excavated soil, rocks and
other
materials. Booms are typically connected to the top of the tanks to connect a
vacuum
hose to the tank. The boom allows the user to move an input end of the vacuum
hose
about the truck during excavation operations. Due to the weight of this
equipment, the
mass of the excavated materials and the stress loads imparted by moving the
swing
boom about, the tanks are typically made up of steel with 1/4 inch to 1/2 inch
thick
walls. A stress load may also be referred to as a mechanical stress.
Furthermore, many
tanks have thick walls or further physical reinforcements, such as 'extension
members,
that are connected to the tank to accommodate the stress loads imparted upon
the tank
by the moving boom. In other examples of vacuum trucks, the swing boom can
have a
separate support-structure that connects the swing boom directly to the vacuum
truck.
In order to accommodate the weight associated with the tanks and the further
physical reinforcements or separate support-structure, a typical vacuum-truck
has two
or three rear-axles. While the trucks with multiple rear-axles can support the
weight of
the vacuum-excavation apparatus and can carry heavy loads of debris materials
within
the tank, these trucks have limited maneuverability, low fuel-efficiency and
can cause
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damage to roadways. Furthermore, many jurisdictions require a specialized
operator's
license to operate trucks with multiple rear-axles.
SUMMARY
Some embodiments of the present disclosure relate to a vacuum-
excavation apparatus. The apparatus comprises a vacuum assembly, a tank and a
boom
assembly that is pivotally connectible to the tank by a boom mount. The boom
mount
is coupled to the tank, for example by one or more support members. The tank
further
comprises an evacuation pipe that is coupled to the boom mount and coupled to
the
tank, for example by one or more further support members. The evacuation pipe
is in
fluid communication with the interior of the tank and it directs the
evacuation fluid
towards a vacuum assembly that is downstream of the tank.
Some embodiments of the present disclosure relate to a tank for use with a
vacuum-excavation apparatus. The tank comprises a boom mount that is coupled
to the
tank, for example by one or more support members. The tank further comprises
an
evacuation pipe that is coupled to the boom mount and to the tank by one or
more
further support members. The evacuation pipe is in fluid communication with
the
interior of the tank and it is configured to direct an evacuation fluid stream
towards a
vacuum assembly that is downstream of the tank. The evacuation pipe and the
one or
more further supports are configured to assist in distributing stress-loads
that are
imparted upon the boom mount and the tank by a boom assembly, or movement
thereof, that is connected to the boom mount. A stress load may also be
referred to
herein as a mechanical stress.
Without being bound by any particular theory, the inventors have found that
coupling the boom mount to either or both of the rear header of the tank and
the
evacuation pipe distributes at least a portion of the stress loads imparted by
the boom-
assembly. In particular, at least a portion of the stress-loads are
distributed areas where
the support members are coupled to the rear header. The stress-loads are also
distributed to the where each of the further support members are coupled to
the tank.
Due to this distribution of at least a portion of the stress loads, some or
all of the tank
can be made with a thinner wall. Thinner tank walls decreases the overall
weight of the
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tank as compared to a typical vacuum-truck tank. Distributing at least a
portion of the
stress loads avoids the necessity of further boom-supporting structures, which
also
decreases the overall weight of the vacuum-evacuation apparatus as compared to
a
typical vacuum-truck tank. Furthermore, further fluid conduction members
between
the tank and the vacuum assembly are not necessary, which also decreases the
overall
weight of the vacuum-excavation apparatus. These features contribute towards a
vacuum-excavation apparatus that is light enough to be supported by a vehicle
with a
single rear-axle chassis.
BRIEF DESCRIPTION OF THE DRAWINGS
Features of the embodiments of the present disclosure will become more
apparent in the following detailed description in which reference is made to
the
appended drawings.
FIG. 1 is a side-elevation view of a vacuum-excavation apparatus that is fixed
upon a
vehicle, according to one embodiment of the present disclosure;
FIG. 2 is a side-elevation view of a tank for use with the vacuum-excavation
apparatus
of FIG. 1, according to one embodiment of the present disclosure;
FIG. 3 is an isometric view of an upper portion of the tank shown in FIG. 2:
A) shows
one embodiment of a fluid evacuation tube that is coupled to the upper portion
of the
tank; B) shows a partial mid-line cross-sectional view of the portion of the
tank;
FIG. 4 is a side-elevation view of a vacuum assembly according to one
embodiment of
the present disclosure; and
FIG.5 includes example images of stress-load data that were obtained from a
computer
software model.
DETAILED DESCRIPTION
Embodiments of the present disclosure will now be described by reference to
FIG. 1 to FIG. 5, which show representations of a vacuum-excavation apparatus.
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FIG.1 shows a vehicle 10 that can support one embodiment of the present
disclosure that relates to a vacuum-excavation apparatus 11. The vacuum-
evacuation
apparatus 11 comprises various components including a boom assembly 18, a tank
30
and a vacuum assembly 38. The vehicle 10 may be a truck with a chassis that
.has one
or more rear-axles. = In some embodiments of the present disclosure, the truck
10 has a
single rear-axle.
The boom assembly 18 comprises a vacuum tube 20 and a support arm 24. The
vacuum tube 20 has an input end 22 that is in fluid communication with other
sections
of the vacuum-excavation apparatus 11. The support arm 24 is pivotally
connectible to
the tank 30. The support arm 24 supports the vacuum tube 20 so that the input
end 22
can be positioned adjacent material to be excavated during excavation
operations in the
vicinity of the vehicle 10. As described further below, the input end 22 is
fluidly
connected to the vacuum assembly 38 so that during excavation operations
materials
such as rocks, soil, ice and other debris, collectively debris materials, are
fluidized,
sucked into the input end 22 and conducted to other sections of the vacuum-
excavation
apparatus 11. In some embodiments of the present disclosure the boom assembly
18
weighs between about 550 pounds and about 650 pounds (one pound is equivalent
to
about 0.454 kilograms). During excavation operations when debris material is
conducted through the vacuum tube 20, the boom assembly 18 may impart loads of
up
to 1100 pounds, which may be inclusive of any operator contribution that occur
during
excavation operations. In some embodiments of the present disclosure the boom
assembly 18 may also be extendible and retractable to increase the distance
that the
input end 22 can reach. The support arm 24 may have a retracted length of
about 10
feet and an extended length of about 18 feet. In some embodiments of the
present
disclosure, the support arm 24 has a retracted length of about 12 feet and an
extended
length of about 16 feet. The boom assembly 18 and movement thereof impart
stress
loads on the tank 30. A stress load may also be referred to herein as a
mechanical
stress. As will be discussed further below, embodiments of the present
disclosure
distribute at least a portion of these stress-loads to various structures and
locations of
the tank 30. This distribution of at least a portion of the stress loads
allows the tank 30
to be constructed of less material and, therefore, to have a lighter overall
weight.
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FIG.2 shows one embodiment according to the present disclosure that relates to
the tank 30. The tank 30 is made up of one or more walls made of a rigid
material, for
example A36 steel, high-strength steel and aluminium. The tank 30 comprises a
front
header 32, a middle section 33 and a rear header 34 all of which define a tank
space
30A therein. The front header 32 and the rear header 34 define a longitudinal
axis of
the tank 30, shown as X in FIG. 2 and FIG. 3A. The tank 30 also has a lower
surface
31 and an upper surface 35.
In some embodiments of the present disclosure, the front header 32 defines an
access port 62. The access port 62 provides access into the tank space 30A,
which may
be useful for cleaning or maintenance of the tank 30. The access port 62 may
be
covered by a releasably sealable door (not shown). In some embodiments of the
present disclosure the rear header 34 defines one or more ports therethrough.
For
example, the rear header 34 may define a debris port (not shown) with a debris
chute 66
and a releasably sealable debris-chute door 66A. The rear header 34 may also
define an
ancillary port 68 that is covered by a releasably sealable door (not shown).
The
ancillary port 68 may be used for visual inspection of the tank space 30A
and/or to
connect further tubes or pipes to the tank 30. The lower surface 31 may define
one or
more drain holes (not shown) each of which may be covered by a drain valve 60.
The
lower surface 31 may also include one or more mounting rails 62 for connecting
the
tank 30 to the vehicle 10.
In some embodiments of the present disclosure the front header 32 and the rear
header 34 have a thickness between about 1/8 of an inch and about '/2 of an
inch (an
inch is equivalent to about 0.0254 meters). In some embodiments of the present
disclosure the middle section 33 has a thickness between about 1/16 of an inch
and
about 5/16 of an inch. In some preferred embodiments of the present disclosure
the
front header 32 and the rear header 34 have a thickness that is about 1/4 of
an inch and
the middle section 33 has a thickness that about 3/16 of an inch thick. In
these
preferred embodiments of the present disclosure the tank may weigh about 3500
pounds. Decreasing the thickness of the middle section from 1/4 of an inch to
3/16 of an
inch may result in a decrease of about 400 pounds in total tank weight. A
comparative
tank that has a front header, a rear header and a middle section that all have
a thickness
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of 1/2 of an inch weighs about 2400 pounds more than the preferred embodiments
of the
tank 30 described herein, with other dimensions and materials being
substantially
similar.
FIG. 3A and FIG. 3B show an upper portion of some embodiments of the tank
30. The boom mount 28 extends upwardly from the upper surface 35. In some
embodiments of the present disclosure the boom mount 28 is coupled to the
upper
surface 35 of the tank 30. As referred to herein, the terms "couple" and
"coupling"
may refer to the manner by which two components of the vacuum-excavation
apparatus
11 can be physically joined together so that stress loads may be distributed
between the
coupled components or from one to the other. For example, coupling may occur
by
welding that provides a weld-bead height that is the same as or close to the
thickness of
the two components that are being coupled together. In some embodiments of the
present disclosure, the two components that are being coupled together are not
the same
thickness, in which case the weld-bead height may be the same or close to the
thickness
of the thinner component, or not. For example, in some embodiments of the
present
disclosure, a weld-bead height of about 1/8 of an inch to about 1/2 of an
inch is suitable
for coupling, as described herein. In further embodiments of the present
disclosure, a
weld-bead height of about 1/4 of an inch is suitable for coupling, as
described herein.
The boom mount 28 defines a boom mount aperture 28A that provides fluid
communication through the upper surface 35 to the tank space 30A therebelow
(see
FIG. 3B). In the embodiment shown FIG. 3, the boom mount 28 has a mounting
flange
26. The mounting flange 26 is connectible to the boom assembly. 18 via one or
more
connection members (not shown) and the pivoting capability of the boom
assembly 18
is achieved by the support arm 24 including a pivot member. However, as will
be
appreciated by those skilled in the art, the boom mount 28 may connect with
the boom
assembly 18 in various manners that don't require a mounting flange 26 but
still permit
pivoting movement of a connected boom assembly 18. In some embodiments of the
present disclosure the boom assembly 18 may pivot by rotating about an axis
that is
substantially perpendicular to the longitudinal axis X of the tank 30. For
example, the
boom assembly 18 may rotate along a first plane that is substantially parallel
to a rear
axle of the truck 10 with about 300 to about 340 degrees of rotational
freedom, when
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viewed from above. In some embodiments of the present disclosure the boom
assembly 18 may also rotate above and below the first plane by about 30
degrees.
The boom mount 28 is coupled to the rear header 34 by one or more supporting
members 50. In some embodiments the one or more supporting members 50 are
coupled to both of the boom mount 29 and the rear header 34. The one or more
supporting members 50 can also be referred to as struts or gussets. In the
embodiment
depicted in the appended figures two supporting members 50 are shown, however
this
is not intended to be limiting. The one or more supporting members 50 may be
made
of a rigid material, for example A36 steel, high-strength steel and aluminium.
The one
or more supporting members 50 can distribute at least a portion of a stress
load that is
imparted on the boom mount 28 to the tank 30 for example the rear header 34.
The
coupling of the boom mount 28 to the rear header 34 by the one or more
supporting
members 50 distributes a portion of a stress load that is imparted upon the
boom mount
28 by a connected boom assembly 18 and/or movement thereof.
An evacuation tube 52 is coupled to the upper surface 35 of the tank 30. The
evacuation tube 52 may also be referred to as an evacuation pipe, a suction
tube and a
suction pipe. The evacuation tube 52 defines an interior evacuation tube space
52A.
The evacuation tube 52 provides fluid communication between the tank space 30A
and
the vacuum assembly 38. In some embodiments of the present disclosure, the
upper
surface 35 of the tank 30 defines an evacuation slot 56 therethrough (see FIG.
3B). The
evacuation tube 52 also defines an evacuation tube slot 55. The evacuation
tube slot 55
is in fluid communication with the evacuation slot 56. For example, the
evacuation
tube 52 may overlay a portion or all of the evacuation slot 56. This
arrangement
defines a fluid pathway from the tank space 30A, through the slots 52, 55 into
the
evacuation tube space 52A and onto the vacuum assembly 38.
The evacuation tube 52 also participates in distributing at least a portion of
the
stress loads that can be imparted on the boom mount 28 and the tank 30 by the
boom
assembly 18 and movement thereof. One end of the evacuation tube 52 is coupled
to
the boom mount 28. This coupling may distribute at least a portion of the
stress loads
that are imparted upon the boom mount 28 to the evacuation tube 52. In some
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embodiments of the present disclosure the tank 30 may also include one or more
further
support members 54 that are coupled to the middle section 33 and the
evacuation tube
52, for example by welding. The one or more further supporting members 54 can
also
be referred to as struts or gussets. In the embodiment depicted in the
appended figures
three further supporting members 54 are shown, however this is not intended to
be
limiting. The one or more further supporting members 54 are made of a rigid
material,
for example steel. The one or more further supporting members 54 can
distribute at
least a portion of a stress load that is imparted on the evacuation tube 52 to
the middle
section 33 of the tank 30.
As shown in FIG. 4 the evacuation pipe is physically and fluidly connected to
the vacuum assembly 38. FIG. 5 shows a vacuum-assembly flange 300, which is
where
the evacuation tube 52 physically and fluidly connects to the vacuum assembly
38. The
components of the vacuum asseMbly 38 are known and include one or more
cyclones
40. The cyclones 40 direct a flowing evacuation stream 102 into a circular
pattern
which separates out at least a portion of any debris materials from within the
evacuation
stream 102. The vacuum assembly 38 also includes a conduit 42 that that
fluidly
communicates a cyclone-output stream 104 to one or more filters 44. The one or
more
filters 44 remove further debris materials from the cyclone-output stream 104.
A filter-
output stream 106 then passes through one or more vacuum blowers 44 to form an
exhaust stream 106 that exist the vacuum-excavation apparatus 11 by an exhaust
port
48. The one or more vacuum blowers 44 may include a silencer mechanism, or
not.
In operation, the one or more vacuum blowers 44 generate a pressure
differential that drives the flow of fluids and any debris materials entrained
therein
from the input end 22 to the exhaust port 48. The pressure differential
creates a suction
force at the input end 22 of the vacuum tube 20. A pressurized fluid, either a
gas or
liquid, is directed at the material to be excavated to generate a stream of
fluidized
debris-material 100. The debris material becomes fluidized, even if only
temporarily,
in that the debris material is loosened from the surround materials and it can
become
airborne or otherwise drawn into the input end 22 by the suction force. The
stream of
fluidized debris-material 100 includes air and the fluidized debris-material,
all of which
are conducted through the vacuum tube 20 into the tank 30. Within the tank 30.
at least
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a portion of the debris material will settle out of the first stream 100 to
create the
evacuation stream 102 that has a lower debris-material content than the stream
of
fluidized debris-material 100. Under the influence of the pressure gradient
created by
the one or more vacuum blowers 44, the evacuation stream 102 passes through
the slots
55, 56 into the evacuation tube 52 for conduction to the vacuum assembly 38.
The
evacuation stream 102 is processed in the vacuum assembly 38 as described
above.
As the input end 22 is moved about the vehicle 10 to draw more debris material
into the stream of fluidized debris-material 100, the boom assembly 18 call
pivot about
the boom mount 28. This pivoting imparts stress loads on the boom mount 28.
Due to
the coupling of the evacuation tube 52 and the one or more support members 50
to the
boom mount 28, at least a portion of the stress load are distributed to the
middle section
33 and the rear header 34 of the tank 30. This stress load distribution allows
a greater
surface area of the tank 30 to bear portions of the stress loads. This may
reduce or
avoid focusing the stress-loads moments on smaller areas of the tank 30, which
smaller
areas could be susceptible to stress failures. As described above, the stress
load
distribution allows portions of the tank 30, for example the middle section
33, to be
made with thinner walls than a typical vacuum-truck tank, which reduces the
overall
weight of the vacuum-excavation apparatus 11.
FIG. 5 shows examples of stress-load finite element analysis data that were
calculated using the ANSYS simulation software (ANSYS is a registered
trademark
of SAS IP Inc.). The calculated stress-load data was superimposed over a wire
diagram
of the tank 30. For these calculations the total vertical-load applied was
about 2050 lbf
and the applied moment was 2e5 inch-lbf with the boom assembly 18 positioned
off
one side of the tank 30 (to the left of the tank 30 when viewed looking
straight at the
rear header 34) so that the direction of the moment was applied at least at
the mounting
flange 26. Points of stress 200 are shown in FIG. 5 where the calculated
stress load
values range between about 6750 pounds per square inch (psi) to about 11250
psi (one
psi is equivalent to about 6.89 kilopascal). Points of higher stress 202 are
also shown
in FIG. 5 where the calculated stress-load values are between about 11250 psi
to about
32384 psi. The data analysis indicated that there are no points of stress 200
or points of
further stress 202 occurring at the vacuum-assembly flange 300.
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FIG. 5 also shows that there are points of stress 200 at least where the
.support
members 54 terminate on the middle section 33 of the tank 30 (distal from the
evacuation tube 52). There are also points of stress 200 where the evacuation
tube 52 is
coupled to the boom mount 28 and along the longitudinal axis of the tank 30
where the
evacuation tube 52 is coupled to the upper surface 35. There are further
points of stress
200 proximal to where the support members 50 are coupled to both of the rear
header
34 and the boom mount 28. FIG. 5C shows that there are points of stress 200 at
least
along lateral sides of the support members 50, at the point where the boom
mount 28 is
coupled to the upper surface 35 and between the upper surface 35 (in the
middle section
33) and an upper portion of the rear header 34. FIG. 5C also shows that there
are points
of higher stress 202 on the mounting flange 26, the inner surface of the boom
mount 28
(on the side where the boom assembly is extending from), at the points -where
the
support members 50 are connected to the boom mount 28 and the rear header 34
and
along an upper surface of the support members 50.
Without being bound by any particular theory, the stress-load data indicates
that
the stress loads that are imparted upon the boom mount 28 by a connected boom
assembly 18 are at least partially distributed to the rear header 34, the
evacuation tube
52, the support members 50, the further support members 54 and the middle
section 33.
In some embodiments of the present disclosure the evacuation tube 52 includes
a pressure-relief valve 53 that when opened provides fluid communication
between the
evacuation tube space 52A and the surrounding atmosphere. When closed the
pressure-
relief valve 53 provides a fluid-tight seal.
In some embodiments of the present disclosure, the vacuum-excavation
assembly 11 may be used to move liquids from a reservoir, such as a hole or
tank, into
the tank 30 for storage and transport of the liquids.
