Note: Descriptions are shown in the official language in which they were submitted.
CA 02485819 2004-11-12
INTERIOR SEWER PIPELINE SCARIFYING APPARATUS
FIELD OF INVENTION
The present invention relates to a device for cleaning
the interior surface of a pipe and more specifically for
cleaning the interior surface of a sewer pipe.
BACKGROUND OF THE INVENTION
Pipes used to carry liquids and gases commonly
transport all types of materials including water, natural
gas and liquid sewage. Over time, these pipes require
servicing and cleaning. MacNeil et al. disclose an
automated process for cleaning or restoring the inside of a
pipe in U.S. Pat. No. 6,206,106. Similar apparatuses are
disclosed by French Patent 2 744 469 and German Patent 198
06 350. The apparatuses disclosed by the above three
patents occupy and obstruct a central portion of the pipe.
In other words, nobody has disclosed a device with an
automated process for cleaning or restoring the inside of a
pipe that can remain in the interior of the pipe, even under
active flow conditions.
The interior surface of a pipeline carrying solids,
liquids and gases generally degrades over time as the pipe
walls interact chemically and physically with the substances
flowing through them and air. In particular, a sewer
system's interior walls corrode and deteriorate because
corrosive materials contaminate the surface, degrading the
metal and concrete used to build the sewer pipe. The
corrosive material arises from both the sewage and waste
water itself, and also from the digestible by-products of
bacteria found in the sewage which proliferate in the
anaerobic environment. The corrosion causes the walls of
the sewer pipe to physically decay, eventually reducing
their overall thickness.
1
-------- - --- ----
CA 02485819 2004-11-12
The principle source of corrosion is sulfuric acid,
which arises as a product of the reaction of sewer gases
with water and air in the sewer pipe and the sewer
environment itself. Various metal sulfates found in the
sewage quickly convert into hydrogen sulfide by reducing to
sulfide ions in the waste water, combining
1A
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
with hydrogen in water and outgassing above the liquid as
hydrogen sulfide gas. Additional hydrogen sulfide originates
from bacteria-containing contaminants which accumulate on the
relatively rough concrete below the maximum liquid level.
Bacteria found in these accumulations thrive in the anaerobic
sewer environment producing hydrogen sulfide gas as a respiratory
by-product. Oxygen from the liquid below and oxygen condensing
from the water in the air react with the hydrogen sulfide on the
pipeline walls creating the highly corrosive sulfuric acid. The
sulfuric acid attacks the calcium hydroxide in the concrete sewer
walls leaving calcium sulfates which ultimately crumble and fall
-off the interior of the wall substantially reducing its
thickness.
The waste water level varies over the course of a 24-hour
period. The flow is at its lowest level between 1:00 a.m. and
6:00 a.m. in the morning but it rises distinctly in the daytime
when the pipe may operate near capacity. Because of the gaseous
nature of the hydrogen sulfide, the pipe walls are predominately
corroded in the portions of the wall above the minimum liquid
level. Portions of the walls which are always below the water
level are not subjected to such high concentrations of hydrogen
sulfide gas or sulfuric acid and consequently do not experience
the same level of decay.
Eventually the sewer walls must be restored or they can
suffer permanent damage leading to great expense. The
restoration process is a two-step operation that consists of
first scarifying the interior pipe surface to remove the
contaminants (including any possibly existing outer layers of
corrupted concrete) from the surface of the pipe, i.e. a process
herein defined as scarifying, and then applying a protective
coating over the newly cleaned (scarified) pipe surface.
Attempting to apply a protective coating without first scarifying
the pipe surface is futile because it does not stop the decay
that has already begun underneath the coating. Furthermore, the
2
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
protective coating itself does not adhere well to the
contaminated surface. Thus, scarifying is an essential element
of the restoration process.
As previously mentioned, the sewer typically operates at
high capacity during the day with a decreased flow overnight. In
order to restore the sewer pipes without diverting the flow (a
costly and sometimes impossible alternative), a bulk of the work
must be done at night during the brief period when the flow is at
a minimum. As previously outlined, the restoration process
involves both scarifying the pipe surface and applying a
protective coat. In practice, the rate of restoration is
impaired because manual scarifying takes a proportionally greater
amount of time than does the application of the protective coat.
Automated scarifying processes exist, e.g. MacNeil et al above,
however, presently devices require insertion into the sewer
assembly and then removal from the sewer, all during the brief
period when the sewer flow is at a minimum. Consequently, a need
exists for an automated scarifying or restoration apparatus that
can remain in the sewer during the period when the waste water
level is not at a minimum.
SU M14ARY OF THE INVENTION
The present invention relates to an apparatus for scarifying
the interior surface of a sewer pipe. A rail assembly matching
the circumferential shape of the sewer pipe interior is connected
at its ends to a chassis moveable along the bottom half of the
sewer pipe. For example, if the configuration of the sewer pipe
is semicircular, or cylindrical with a false floor, preferably
the rail assembly will be of an arcuate configuration.
Preferably, the rail assembly of'the present invention will be
easily removed from the chassis to allow entry and removal of the
apparatus through small openings, such as manholes, into the
sewer.
3
CA 02485819 2004-11-12
At least one scarifying head is coupled to the rail
assembly and may traverse in either direction along the rail
assembly. The scarifying head comprises a nozzle assembly
and a driving assembly. The nozzle assembly includes
nozzles which rotate or oscillate, and emit a pressurized
jet of fluid to scarify a circumferential swath of the
interior surface of the sewer pipe. The driving assembly
enables the scarifying head to move back and forth along the
rail assembly.
The scarifying head may be extendible to place the
nozzles proximate the interior surface of the sewer pipe
when the scarifying head is at rest or as it moves back and
forth along the rail assembly.
The present invention may also include guide bars
affixed to the chassis. The guide bars may have wall-
engaging attachments, which move along the interior surface
of the sewer pipe and maintain the orientation of the
apparatus along a longitudinal axis of the pipe when the
apparatus is in use.
An advantage of the present invention is improved rates
of scarifying of the sewer pipe's interior walls. A further
advantage is assurance that the same intensity of scarifying
is applied to the entire surface without the quality
variation that is inherent in manual execution. Further
still, the ability of the scarifying head to traverse in
either direction of the rail assembly enables a
circumferential swath of the interior surface of the sewer
pipe to be scarified without requiring the apparatus to make
several passes back and forth, resulting in a fast and cost-
effective method of scarifying, and making restoration
without diversion a cost-effective possibility.
4
CA 02485819 2004-11-12
Lastly, as the configuration of the apparatus leaves a
central portion of the sewer pipe unobstructed, thereby
enabling it to remain in the sewer for the duration of the
restoration (i.e. even when waste flow is not at a minimum).
This feature results in an increase in productive working
time for scarifying the interior surface of the sewer pipe
when the sewer flow is at a minimum.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the invention will
be apparent from the following detailed description, given
by way of example, of a preferred embodiment taken in
conjunction with the accompanying drawings, wherein:
Figure I is a perspective view of a first embodiment of
the apparatus showing a vehicle, carts, rail assembly, and
scarifying heads;
Figure 2 is a front view of the scarifying head of the
first embodiment;
Figure 3 is a front view of a second embodiment showing
the configuration of the apparatus when it is in use;
Figure 4 is a sectional view along line 4-4 of Figure
3;
Figure 5 is a sectional view along line 5-5 of Figure
4;
Figure 6 is a top view of the second embodiment showing
the track assembly and removable platform;
Figure 7 is a side view of the track assembly and
lateral support for the second embodiment;
Figure 8 is a perspective view of the interior of a
cylindrical pipe depicting a circumferential swath scarified
by a pass of the apparatus.
CA 02485819 2004-11-12
DETAILED DESCRIPTION OF THE INVENTION
Two embodiments envisaged in this invention are
outlined below with reference to the drawings.
The First Embodiment
Referring to Figures 1 and 2 a scarifying apparatus 10
includes at least one scarifying head 20 slidably mounted
between two arcuate, spaced apart rails 12 and 14. The
scarifying head
5A
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
20 is mounted with a pair of low friction brackets or plates 18
slidably engaging the edges of the rails 12 and 14. A rack 16 is
mounted on the underside of one of rails 12 and 14 and a small
reversible hydraulic motor 22 mounted on the scarifying head 20
drives a pinion gear 26 which, in turn, engages the teeth of the
rack 16, causing the scarifying head 20 to move along the rails
12 and 14. At an outer end of the scarifying head 20 is mounted
a pair of outwardly directed nozzles 28 each connected to a
respective branch 30, with each branch coupled to an exchanger 32
which receives a single stream of fluid and splits it into two
streams of equal flow rate for each of the two nozzles 28. An
inlet 31 at another end of the scarifying head 20 is engaged by a
hose end 34 and conducts water to the exchanger 32. Inlet and
outlet hydraulic hoses 36 and 37, respectfully attach to
hydraulic couplings on the hydraulic motor 22.
The exchanger 32 is mounted at the distal end of a
telescoping arm, which includes two telescoping pipes in which
the upper portion of the pipe 21 has a smaller diameter such that
it slides down the lower portion 23. A piston (not shown)
controls the extension of the telescoping arm. Consequently, the
scarifying head 20 can be manipulated so that the outwardly
directed nozzles 28 can be positioned in close proximity to the
pipe walls when the scarifying head 20 is at rest or as the
scarifying head 20 moves back and forth along the rails 12 and
14.
One set of the ends of the rails 12 and 14 are affixed to a
small cart 38A positioned at one side of the sewer pipe to be
cleaned, while the other set of the ends of the rails 12 and 14.
are affixed to another small cart 38B positioned on the other
side of the sewer pipe to be cleaned. Each of carts 38A and 38B
have mounted thereon a guide roller 40A and 40B which prevents
the cart from scraping against the side of the sewer pipe when
the apparatus 10 is in use.
6
CA 02485819 2010-09-08
Carts 38A and 38B are affixed by rigid rods 42A and 42B,
respectively, to a small vehicle 44 powered by hydraulic motors
(not shown) to move the rails 12 and 14 and carts 38A and 38B
along the sewer pipe, while keeping the rails 12 and 14
transverse to the direction of travel. Although a hydraulic
motor is used in this embodiment, any power providing means of
both external or on-board types but preferably exhaustless may be
used for this application. The direction of motion of the
vehicle is that of arrow 58. However, in the event of movement
in direction 60 is desired, an additional rigid rod may be
connected to rods 42A and 42B to keep the latter rods
from moving towards each other.
Rails 12 and 14 can accommodate several scarifying heads 20
at the same time. Generally the scarifying heads 20 are
positioned so that each travels back and forth along the rails 12
and 14 the same distance, with the net result being that together
the scarifying heads 20 cover the entire circumference of the
rails 12 and 14.
A controller 62 mounted adjacent to motor 22 receives a
signal from a position sensor (not shown) which senses the
position of the scarifying heads 20 and is responsive to command
signals received from controller 62 to establish the trajectories
of the scarifying heads 20 along the rails 12 and 14. For
example, if three scarifying heads were used, each scarifying
head 20 would usually be set to traverse approximately 1/3 of the
circumference of the rails 12 and 14 by each traveling in one
direction until the end of a respective path is reached and the
opposite to cover the same path in an opposite direction.
As the scarifying head 20 moves along rails 12 and 14, water
supplied under pressure through hose 34 flows into exchanger 32
and causes nozzles 28 and nozzle branches 30 to rotate. Arrows
7
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
64 and 66 in Figure 2 indicate the direction of rotation of the
nozzle assembly. Jets of water are emitted by the rotating
nozzles 28 and impact on a surrounding interior surface of a
sewer pipe (not shown). Typical water pressures used are in the
range of 20,000 to 30,000 psi.
Vehicle 44 includes a chassis 70, a track assembly 68 and an
on-board hydraulic motor (not shown). Although a track assembly
68 is shown in this embodiment, any actuator capable of moving
the vehicle 44 under power from the hydraulic motor may be used.
The hydraulic motor 22 is coupled by hydraulic hoses 36 and 37
that pass through a manhole.(not shown) to an external hydraulic
pump (not shown). An electrical cable from an external generator
(not shown) also feeds through the manhole and couples electrical
power to the vehicle 44. An on-board power supply converts this
electrical power to low voltage DC for application to the various
switches in response to commands from an on-board controller (not
shown). The switches control the speed and direction of the
vehicle 44. An on-board battery (not shown) can also power the
electrical system which controls the speed and direction of the
vehicle 44 as well as the movement of the scarifying heads 20.
The hydraulic motor 22, switches, and on-board power supply are
covered by protective boxes (not shown) to protect their
sensitive parts from debris when the waste water level when is
not at a minimum.
The vehicle 44 and carts 38A and 38B are outfitted with a
drawbar (not shown) which holds the hoses away from the apparatus
so that it may easily travel in either direction without running
over the hoses. The drawbar may also hold the hoses close to the
apparatus to enable debris to flow more easily through the sewer
pipe when the apparatus is not in use.
An additional safety feature not shown in the drawings is a
"deadman", which is a safety switch operative to cut off the high
8
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
pressure from the moving parts of the apparatus. The deadman is
useful in both emergency situations and when minor adjustments
must be made to the apparatus during a job.
In order to reduce the size of the apparatus, the rails 12
and 14 may easily be removed from the carts 38A and 38B to enable
the apparatus to enter small access opening into the sewer pipe.
Once assembled, the configuration of the apparatus enables it to
remain in the sewer pipe for the duration of the restoration.
The Second Embodiment
Referring to Figures 3 and 4 a second embodiment of the
scarifying apparatus 10 includes at least one scarifying head 20
slidably mounted between two arcuate, spaced apart rails 12 and
14. At an outer end of the scarifying head 20 is mounted a pair
of outwardly directed nozzles 28 each connected to a
corresponding branch 30, with each branch coupled to an exchanger
32 which receives a single stream of fluid and splits it into two
streams of equal flow rate for each of the two nozzles. An inlet
at another end of the scarifying head 20 is received by a hose
end 34 and conducts water to the exchanger 32.
The exchanger 32 is mounted at the distal end of a
telescoping arm, which includes two telescoping pipes in which
the upper portion of the pipe 21 has a smaller diameter such that
it slides down the lower portion 23. A piston (not shown)
controls the extension of the telescoping arm. Consequently, the
scarifying head 20 can be manipulated so that the outwardly
directed nozzles 28 can be positioned in close proximity to the
pipe walls when the scarifying head 20 is at rest or as the
scarifying head 20 moves back and forth along the rails 12 and
14.
However, in contrast to the first embodiment a pulley system
is used to move the scarifying head 20 along the rails 12 and 14.
9
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
Referring to Figure 3, 4, and 5 the pulley system is shown for a
scarifying system having two scarifying heads 20. The ends of a
fixed length of cable 94A and 94B are attached to either side of
a carriage 87 of the scarifying head 20. To guide the ends of
the cable, a sheave 81 is attached to each side of the carriage
87 just under the ends of the cable 94A and 94B. One side of the
cable 94A and 94B is then lead around a motor controlled sheave
88'mounted to the chassis 51 of the track assembly 68, while the
other side of cable 94A and 94B is guided over a motor controlled
sheave 72 connected to a hydraulic motor 71. The hydraulic motor
71 is suspended from the rail assembly 12 by a rigid pole 75.
The hydraulic motor 71 causes the motor controlled sheave 72 to
rotate, which, in turn causes the cable 94A and 94B to move over
the motor controlled sheave 72, and sheaves 88 and 81, which
results in the scarifying heads 20'moving along the rails 12 and
14. Inlet and outlet hydraulic hoses 71A and 71B attach to hoses
coupling on the hydraulic motor 71. Alternatively, a chain
passing over the rim of the sheaves 72 and 81 may be used.
As the scarifying head 20 moves along rails 12 and 14, water
supplied under pressure through hose 34 flows into exchanger 32
and causes nozzles 28 and nozzle branches 30 to rotate. Arrows
64 and 66 in Figure 4 indicate the direction of rotation of the
nozzle assembly. Jets of water are emitted by the rotating
nozzles 28 and impact on a surrounding interior surface of a
sewer pipe (not shown). Typical water pressures used are in the
range of 20,000 to 30,000 psi.
One set of the ends of the rails 12 and 14 are affixed to
socket 74A at one side of the track assembly 68, while the other
set of the ends of the rails 12 and 14 are affixed to-another
socket 74B positioned on the other side of the track assembly 68.
In order to reduce the size of the apparatus, the rails 12 and 14
may easily be removed from the sockets 74A and 74B to enable the
apparatus to enter small access opening into the sewer pipe.
CA 02485819 2010-09-08
A platform 82 is located between the track assemblies 68 to
keep the track assemblies transverse to the direction of travel.
The track assemblies 68 are powered by hydraulic motors 86 to
move the rails 12 and 14 along the sewer pipe. Inlet and outlet
hydraulic hoses 86A and 86B attach to hoses coupling on the
hydraulic motors 86. Although hydraulic motors 86 and 71 are
used in this embodiment, any power providing means of both
external or on-board types, but preferably exhaustless may be
used for this application. A battery 78 and a hydraulic solenoid
80 are mounted on the platform 82. Referring to Figure 6, the
platform 82 may be removed from the chassis 51 of the track
assemblies 68 by pins 84A, 84B, 84C, and 84D to protect the
battery 78 and hydraulic solenoid 80, as well as to improve waste
water flow through the sewer pipe when it is not at a minimum.
Referring to Figure 3, limit switches 76A and 76B are also
removably mounted to the chassis 51 by pins 73A and 73B. The
configuration of the apparatus enables the remaining portions of
the apparatus to remain in the sewer pipe for the duration of the
restoration.
The hydraulic motors 86 and 71 are coupled through hydraulic
hoses to the hydraulic solenoid 80 and to an external hydraulic
pump (not shown). The battery 70 powers the electrical system
for application to the various switches. Alternately, an
electrical cable from an external generator (not shown) may be
used to couple electrical power to the scarifying apparatus 10.
The limit switches 76A and 76B send signals to an on-board
controller (not shown) coupled to the hydraulic solenoid 80 to
cause the scarifying heads to change their speed and/or direction
along the rails via the hydraulic motor 71. For example, if two
scarifying heads were used, each scarifying head 20 would usually
be set to traverse approximately 1/2 of the circumference of the
rails 12 and 14 by each traveling in the same direction until one
scarifying head 20 reached the end of a respective path where one
11
CA 02485819 2004-11-12
WO 03/097260 PCT/CA03/00704
of the limit switches 76A and 76B is located, and then reversing
direction until signaled by the other limit switch 76A and 76B to
change direction again. While the limit switches 76A and 76B
control the direction of the scarifying heads 20, switches (not
shown) also send signals to the on-board controller (not shown)
to control the direction of the track assemblies 68 via the
hydraulic solenoid 80.
An additional safety feature not shown in the drawings is a
"deadman", which is a safety switch operative to cut off the high
pressure from the moving parts of the apparatus. The deadman is
useful in both emergency situations and when minor adjustments
must be made to the apparatus during a job.
Referring to Figure 7 a lateral support 53 is attached to
the rails 12 and 14 and chassis by a socket 55 on each side of
the track assemblies 68. The lateral support may easily be
removed from the rails 12 and 14 when the scarifying apparatus 10
is not in use.
In the first and second embodiments an apparatus with an
arcuate rail assembly will be preferred when the sewer pipe is a
semicircular shape. However, referring to Figure 8 the arcuate
rail assembly may also be used in a cylindrical pipe by using a
false floor 92 layered on top of the minimum flow mark 90. As
the scarifying heads transverse back and forth along the rails,
the apparatus can clean an entire circumferential swath in one
pass. The circumferential swath is approximately the same width
96 as the-diameter between the nozzles 28 which are coupled to
the branches 30 of the scarifying head 20. As most of the
corrosion occurs above the minimum flow mark 90, use of the false
floor 92 is acceptable for restoration applications.
Alternatively, if the sewer pipe is another shape, such as
rectangular, the rails of the apparatus may be configured to
12
CA 02485819 2010-09-08
match the shape of the pipe. Further, the rail assembly may
consist of only one rail with a slot to which the scarifying
head 20 may be coupled.
While the nozzle assembly in the above description is
described as rotating, it may instead oscillate or both rotate
and oscillate.
Accordingly, while this invention has been described with
reference to illustrative embodiments, this description is not
intended to be construed in a limiting sense. Various
modifications of the illustrative embodiments, as well as other
embodiments of the invention, will be apparent to persons
skilled in the art upon reference to the description. It is
therefore contemplated that the appended claims will cover any
such modifications or embodiments as fall within the true scope
of the invention.
The invention may be summarized, at least in part, by the
following enumerated statements:
Statement 1. The invention comprises an apparatus for
scarifying an interior surface of a sewer pipe, characterized
by: a. a support assembly (38) moveable along an interior of
said sewer pipe supported from a bottom half thereof; b. a rail
assembly (12, 14) supported on its ends by said support assembly
juxtaposed to the interior surface of said sewer pipe, said rail
assembly matching a circumferential trajectory of said sewer
pipe; c. at least one scarifying head (20) coupled to and
moveable in either direction along said rail assembly, said
scarifying head having: i. a nozzle assembly coupled to said
scarifying head having at least one nozzle (28), operative to
13
CA 02485819 2010-09-08
rotate or oscillate and to emit a jet of fluid against the
interior surface of said sewer pipe and to scarify the interior
surface of said sewer pipe; and ii. a driving assembly (22, 71)
coupled to said scarifying head, operative to drive said
scarifying head along said rail assembly over a pre-selected
trajectory wherein said support assembly, rail assembly and
scarifying head are positioned proximate said interior surface
of said sewer pipe so as to leave unobstructed a central portion
of said sewer pipe so that sewage can flow through said sewer
pipe substantially unimpeded by said apparatus.
Statement 2. The invention further comprises the
apparatus of Statement 1, wherein said support assembly is a
pair of carts.
Statement 3. The invention further comprises the
apparatus of Statement 2, wherein said pair of carts is coupled
to a vehicle (44), said vehicle moveable along said interior of
said sewer pipe.
Statement 4. The invention further comprises the
apparatus of Statement 3, wherein said vehicle is supported and
propelled by a pair of spaced apart tracks (68).
Statement 5. The invention further comprises the
apparatus of Statement 2, wherein said pair of carts are each
supported and propelled by a pair of spaced apart tracks (68).
Statement 6. The invention further comprises the
apparatus of Statement 1, wherein said support assembly is a
single vehicle.
Statement 7. The invention further comprises the
apparatus of Statement 6, wherein said single vehicle is
supported and propelled by a pair of spaced apart tracks.
Statement 8. The invention further comprises the apparatus of
Statement 1, wherein said nozzle assembly further comprises: a.
13a
CA 02485819 2010-09-08
an exchanger coupled to an external source of fluid; b. a
plurality of branches coupled to and radially spaced around said
exchanger; and c. a distal end on each branch of said plurality
of branches having said at least one nozzle.
Statement 9. The invention further comprises the
apparatus of Statement 8, wherein said external source of fluid
is a pressurized fluid source remote from said sewer pipe.
Statement 10. The invention further comprises the
apparatus of Statement 1, wherein said rail assembly further
comprises a rack having gears located on an underside of said
rail assembly
Statement 11. The invention further comprises the
apparatus of Statement 10, wherein said driving assembly is
operative to drive said scarifying head back and forth along
said pre-selected trajectory.
Statement 12. The invention further comprises the
apparatus of Statement 1, wherein said rail assembly further
includes two recessed edges located on opposing inner sides of
said rail assembly.
Statement 13. The invention further comprises the
apparatus of Statement 12, wherein said driving assembly further
comprises: a. a carriage having a first side substantially
perpendicular to said rail assembly and a second side, opposite
said first side and substantially perpendicular to said rail
assembly; b. at least one roller 85 coupled to said carriage
between said first and second sides, said at least one roller
operative to engage said recessed edge; c. a first upper sheave
coupled to said first side of said carriage and a second upper
sheave coupled to said second side of said carriage; d. a lower
sheave coupled to said support assembly; e. an intermediate
sheave coupled to said rail assembly; f. a cable coupled to said
13b
CA 02485819 2010-09-08
first side of said carriage, and passing over said first upper
sheave, said lower sheave, said intermediate sheave, said second
upper sheave and coupled to said second side of said carriage;
and g. a motor coupled to and operative to rotate said
intermediate sheave; wherein rotation of said intermediate
sheave in a first direction draws the cable to move said
scarifying head in a first direction, and rotation of said
intermediate sheave in a second direction draws the cable to
move said scarifying in a second direction opposite said first
direction.
Statement 14. The invention further comprises the
apparatus of Statement 1, wherein said support assembly is
moveable incrementally along said interior of said sewer pipe.
Statement 15. The invention further comprises the
apparatus of Statement 1, wherein said apparatus is operative to
scarify a circumferential swath of said interior surface of said
sewer pipe perpendicular to a direction of travel of said
support assembly.
Statement 16. The invention further comprises the
apparatus of Statement 1, wherein said rail assembly is readily
detachable from said support assembly to enable said support
assembly to pass through an access opening into said sewer pipe.
Statement 17. The invention further comprises the
apparatus of Statement 1, including one or more extendible guide
bars extending out from said support assembly, and having a wall
engaging attachment at a distal end thereof, each of said one or
more guide bars operative to move along an interior surface of
said sewer pipe and maintain orientation of said apparatus along
a longitudinal axis of said sewer pipe.
Statement 18. The invention further comprises the
apparatus of Statement 1, wherein said apparatus includes three
l3c
CA 02485819 2010-09-08
scarifying heads spaced apart along said rail assembly such that
each of said scarifying heads transverses along 1/3 of said rail
assembly, each scarifying head operative to scarify a
corresponding region of said interior surface of said sewer
pipe.
Statement 19. The invention further comprises the
apparatus of Statement 1, wherein said rail assembly is arcuate.
Statement 20. The invention further comprises the
apparatus of Statement 1, further comprising at least one
drawbar to hold hoses and cables necessary for said apparatus to
operate in a position away from said apparatus when said
apparatus is in use and in a position close to said apparatus
when said apparatus is not in use.
Statement 21. The invention further comprises the
apparatus of Statement 1, wherein said bottom half thereof is a
false floor mounted within said sewer pipe.
Statement 22. The invention further comprises the
apparatus of Statement 1, wherein said scarifying head is
reversibly extendible to place said at least one nozzle
proximate said interior surface of said sewer pipe when said
scarifying head is either at rest or moving over said pre-
selected trajectory.
13d
