Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Inner Treatment Process and Device for Inaccessible Pipes
The present invention relates to a process and a device for
working conduits, the interior of which is inaccessible to
persons, such as sewers. In particular, the invention makes it
possible to close or open lateral branches of such conduits and to
l- perform repairs of damaged sections.
! For this, so-called conduit repair robots are so far known,
t which comprise a small, elongated, self-propelled vehicle which
can travel in the conduits and is embodied as a robot in that it
has working tools, such as a cutter head as well as injectors and
trowel devices. In addition, the robot vehicle is equipped with a
- video camera and can therefore be operated by a supply and control
, unit located above ground. In most cases the supply and control
unit is permanently installed in a special vehicle, for example
the body of a truck, the body of a trailer or an easily movable
container. The cutter of the cutter head is movable. With its
aid and by means of video monitoring it is possible to cut out a
section to be repaired, after which filler material is injected
into the cut-out section from a cartridge housed in the robot
vehicle. Finally, the section is filled by means of an extruding
shoe and smoothed.
Conventional robots have several disadvantages which limit
their use or reduce their efficiency. For example, one such
disadvantage is seen in that the cutter cannot operate forward but
only laterally in respect to the elongated robot vehicle. Also,
for technical reasons the cutters of conventional robots often
have an insufficient output or rpm. Finally, in case of extended
work phases it is necessary to remove the robot vehicle from the
conduit for replacing the used-up cartridge by a fresh, full one.
Much valuable time is lost in this process during which the entire
installation, which does represent a large investment, is shut
down.
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- It is the object of the present invention to remove these
disadvantages and to provide a more technically advanced process
and a device for its execution, which generally allow wider
technical application possibilities with increased efficiency of
their effects, and to realize improved technical solutions in many
respects.
The object is attained by means of a process for the
interior working of conduits which cannot be entered by persons,
wherein a remote-controlled robot, having a video-monitored
working head, is brought by an above ground supply and control
unit into the conduit to be worked, cuts out the section to be
opened or repaired or places a pig at the spot to be closed off
- and braces it in the conduits by expanding it, wherein the process
is distinguished by the characterizing features of claim 1.
Another aspect of the object to be achieved is attained by
a process for the interior working of conduits which cannot be
entered by persons in accordance with claim 1, wherein the cutting
of the spot to be opened is performed in accordance with the
characterizing process steps of claim 2.
Finally, the object is attained by a device for executing
the process in accordance with claim 1 or 2, having a remote-
controlled robot, which is to be brought into the conduit to be
worked, with a video-monitored working head and an associated
supply and control unit, wherein the device is distinguished by
the characterizing features in accordance with claim 3.
The invention also permits frontal operations, i.e. at a
dead end of a conduit or a blockage at the front. The robot is
particularly efficient because of its special technical embodiment
and operation is correspondingly efficient and versatile. Much
time can be saved because mixing of the filler material takes
place at the work face by means of a continuous supply of an
appropriate epoxy resin. In addition, only as much filler
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material as is actually needed is prepared at any time and no
unnecessary waste is produced, which is unavoidable when using
cartridges the contents of which are often only partially used up
in a work phase.
The device of the invention will be described below by
means of drawings of an exemplary embodiment and the function of
the individual components will be described so that the process of
the invention and its specific features and advantages also become
clear.
Shown are in:
Fig. 1: a composite train consisting of a locomotive,
control valve unit and robot;
Fig. 2: the working head, embodied as a cutter head in this
case and pivotably seated between the fork tips, viewed from
above;
Fig. 3: the cutter head with cutter and the video camera,
pivotably seated in the also pivotable fork, viewed from the side;
Fig. 4: the cutter head in cross section viewed from the
side;
Fig. 5: the cutter head between the fork tips, viewed from
the front, with the friction shafts which make it possible to
extend the cutter head;
Fig. 6: the extrusion unit mounted on the cutter head;
Fig. 7: the opposite flow helical mixer, partially in
section, viewed from the side;
Fig. 8: the synchronous drive of the locomotive with
toothed wheels.
All essential components of the device of the invention are
shown in a total view in Fig. 1. The device forms a composite
train of a locomotive 8, control valve unit 14 and the actual
robot 1. These individual composite elements 1, 8 and 14 are
connected with each other via pivot hinges 15, 16. The elements
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1, 8 and 14 can thus be pivoted up and down as well as sideways in
respect to each other. The entire composite train is very
flexible on account of these pivot hinges 15, 16 and it is even
possible ~o travel through curves with the smallest radii possibly
occurring in sewers. The locomotive 8 is responsible for
i displacing the entire composite train. For this purpose it must
; ~ be able to exert as large as possible a pulling or pushing power.
~ To do this, it is equipped with a synchronous all-wheel drive
i~ acting via four wheels 12 with special cleated tires 2~ which
assure good adhesion on the mostly wet and slippery inner walls of
the conduits. Propulsion is obtained via a single electric motor
housed in the locomotive 8 and will be described in detail later
on. The supply and control lines 3, which can be approximately
i` 200 m long, extend through the locomotive 8 and must be pulled by
the locomotive 8 from the access shaft from which the composite is
inserted into the conduit to be worked. These are three lines
with different functions, namely an electric control and supply
line 33 for the electric supply of the electric motor as well as
the control and measuring signals, furthermore a pneumatic supply
line 34 and supply lines for the epoxy resin to be used, namely
two lines 35 for the two components of the epoxy resin. The lines
33, 34 and 35 extend through the locomotive 8 into the next
element towards the front, the valve control unit 14. An opposite
flow helical mixer is housed in this valve control unit 14, by
means of which the two components of the epoxy resin are
intimately mixed with each other during their passage. The
construction and disposition of this helical mixer will be
described in detail later on. It can be seen from the drawings
that two lines 35 for the two components of the epoxy resin enter
the valve control unit 14, but only one line 35 leaves it, because
- when leaving the valve control unit 14, the epoxy resin is already
ready-mixed for use. Starting at the valve control unit 14, the
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pneumatic supply line 34, although combined in a tube enclosure,
is branched when entering the actual robot 1, in which the
compressed air is required for diverse functions. The robot 1
consists of a cylinder-shaped drive and control part 36. Here, it
is provided with runners 37 or wheels on the exterior, on which it
glides or rolls in the conduit without sustaining damage. This
cylinder-shaped drive and control part 36 is built relatively
heavy, because it must absorb the reaction forces during working
and lend the required stability to the entire robot 1. A disk
wheel 9 is seated like a closing lid at the front of the cylinder-
shaped drive and control part 36. This disk wheel 9 can be
rotated by a compressed air motor via a toothed wheel drive around
the long axis of the robot 1, in fact up to 420. A fork 10 which
has a pivot hinge 13 is mounted on this disk wheel 9. The actual
working head 2 is disposed pivotable by a motor between the fork
ends or fork tips 11. ~he working head 2 can be a cutting unit 4
for cutting out sections of the conduit, or it can be embodied as
a blower unit for bracing pigs, as an extruding unit 23 (Fig. 6)
for extruding and smoothing epoxy resin, as a spinning unit for
the interior coating of conduits, or as a combination of such
units 4, 23. In the illustrated example, the working head 2 is a
cutting unit 4 with a cutter 5. Behind the working head 2, a
video camera 7 with a halogen lamp 21 is mounted in the fork 10
and is pivotable there and can be arrested in any position. In
actuality, the composite train of locomotive 8, control valve unit
14 and robot 1 is most frequently manually pushed from a shaft
into a conduit which is to be worked. The setting of the pivot
angle of the fork 10 at the fork hinge 13 is adapted to the
diameter of the conduit to be worked. Thanks to this hinge 13,
around which the fork can be swiveled over approximately 60, it
is possible to work conduits up to an internal diameter of
approximately 850 mm. After inserting the composite train into
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the conduit, the locomotive 8 pushes the robot 1 and the valve
control unit 14 as far as the desired work place, which is
monitored by video from the supply and control unit, i.e. from
above ground. Advantageously the supply and control unit is
housed in a truck body, the body of a trailer or an easily movable
container. Further operation can take place exclusively from the
control console of this supply and control unit. When pushing the
robot 1 in, the locomotive 8 must pull the supply and control
lines 3, 33 to 35 behind it, for which reason a strong propulsion
unit for the locomotive 8 is imperative.
The detailed arrangement of the working head 2, in this
case the cutting unit 4, is shown in Fig. 2 in a top view. This
cutting unit 4 is pivotably disposed between the fork ends 11.
The drive for its motor-driven pivoting can be seen on one side of
the cutting unit 4. This is a toothed wheel 39 which is engaged
by a worm 41 driven pneumatically, i.e. by a compressed air motor,
from the drive and control part 36 of the robot 1. Power transfer
can take place via universal shafts with universal joints or via a
wire. Thus the cutting unit 4 can be driven into the desired
pivoted position while being monitored by video, and self-locking
of the worm drive assures good stability, so that the cutting unit
4 can easily absorb the reaction forces of the work in the set
pivoted position. The back of the cutting unit 4 is rounded
corresponding to the pivot radius, so that during pivoting by the
motor it does not possibly get caught anywhere.
The fork 10 with the cutting unit 4 disposed in it is shown
in a lateral view in Fig. 3. The fork 10 is mounted on the disk
wheel 9, which can be rotated over 420 via a toothed wheel drive
by means of a compressed air motor. The fork 10 and the working
head 2, in this case the cutting unit 4, disposed between its ends
turns along with the disk wheel 9. The fork 10 has a hinge 13,
around which the front part of the fork lO is upwardly pivotable
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by approximately 60. Thus, in combination with the turning of
the disk wheel g, the result is a wide working range for the
working head or the cutting unit 4 which, with the rotation of the
disk wheel 9, describes a correspondingly large circle. A compact
special video camera 7 with a halogen lamp 21 is disposed
approximately in the center of the extent of the fork 10, the
pivot axis of which is fixed in such a way, that the lens 30 is
directed approximately in the direction of the working point. To
keep the lens 30 clean during cutting operations, a water jet is
directed toward the lens 30, via which it is sprayed with high
pressure when required. The cutting unit 4 with the cutter 5 is
seated in the front between the fork ends 11, where it can be
pivoted in the way indicated by the arrows via the described worm
drive by a motor. So that the video camera 7 itself can also be
pivoted under remote control, it can be placed directly on the
working head 2. Then it is possible to position it more exactly
for viewing the interior conduit walls, in particular the interior
conduit walls of joining conduits.
In Fig. 4 the cutting unit 4 is shown in cross section. It
consists of a housing 18, in which the actual cutting head 17 is
housed so it is translatorily displaceable. The cutter 5 is
pneumatically driven via a turbine 40. A hollow shaft 6 extends
axially along the cutter shaft, through which cooling water can be
pumped, which can cool the actual cutter 5 from the inside and
which then exits laterally. The displacement of the cutting head
17 in the housing 18 takes place pneumatically in both directions.
Maintaining the cutting head 17 in a desired extended position is
accomplished in accordance with the invention by means of
pneumatically operated oil brake cylinders. The oil circulation
supplying the said oil brake cylinders with hydraulic oil is in a
closed loop within the cutting unit 4. In this way it becomes
possible to generate a very high braking force in spite of the
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cutting unit 4 being only supplied with air, so that the cutting
head 17 extended in the housing 18 can absorb large reaction
forces during cutting.
The cutting unit 4 seated between the fork ends 11 of the
fork 10 is shown in a front view in Fig. 5, in which the fork 10
is in an extended position. As shown in this drawing figure, the
fork 10 is rounded on its outside, so that the fork 10 cannot
catch someplace with an edge when the disk wheel 9 rotates inside
a narrow conduit. Also visible is the worm drive for pivoting the
working head 2, in this case the cutting unit 4. The latter
includes the worm 41 driven from the robot housing and the toothed
wheel 39, which is fixedly connected with the pivot shaft of the
housing 18. In accordance with the invention, the cutting head 17
is seated inside the housing 18 by means of two oppositely located
friction shafts of hardened bar steel. Respectively two hardened,
parallel disposed bar steel pieces 19 are fixed on the cutting
head 17 on two sides of the cutting head 17 located opposite each
other. Respectively one single hardened bar steel piece 20 is
disposed on the oppositely located insides of the housing 18 and
rests against the cutting head 17 along respectively one line in
the center between the adjoining bar steel pairs 19. The play of
the friction bearing formed in this manner can be adjusted by
means of the screws 2~ on the housing 18, which prestress the bar
steel pieces 20 and in this way determine their pressing force.
In addition to the pneumatic cylinder 42, the oil brake cylinder
43 is visible. If an extruding shoe is attached to the cutting
head 17, the epoxy resin line is connected at the point 48 in Fig.
6.
The working head can also be a separate blower unit without
a cutting device, having a compressed air nipple for attaching the
inflating hose of a pig equipped with a one-way valve. The pig is
placed in the conduit or an opening to be closed by means of the
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robot 1 and is subsequently inflated by means of compressed air,
so that it is braced in the respective inner conduit. Afterwards
the lateral recesses around the entire pig can be filled with
extruded epoxy resin. The working head can also be a spinning
unit, which essentially has a pneumatically operated spinning
disk, onto which a coating material or paint in liquid form can he
sprayed by a jet on the working head aimed at the spinning disk.
It is possible by means of such a spinning unit to apply interior
coatings to conduits, which are distinguished by a very
homogeneous distribution of the coating material.
The control valve unit 14 contains the electrically
actuated pneumatic valves for controlling the robot 1. All drives
of the robot 1 are operated pneumatically or pneumatically-
mechanically. The disk wheel 9, for one, is turned via the
toothed wheel gear which itself is driven by a compressed air
motor, the working head 2 or the cutting unit 4, on the other
hand, are pivoted by means of the mechanical worm gear where again
the worm is driven by a compressed air motor. In addition, the
cutting head 17 is extended and retracted pneumatically and is
arrested in any desired position by means of pneumatically driven
oil brake cylinders. Finally, the actual cutter drive is
pneumatic, in that a turbine 40 in the interior of the cutting
unit 4 is supplied with compressed air. This drive permits cutter
rpm up to approximately 45,000 rpm and correspondingly high
cutting output. All these functions are controlled via the
electrically actuable air valves in the control valve unit 14.
The opposite flow helical mixer is disposed underneath the control
valve unit 14. Suitably the robot unit 36 contains in its
interior a cross profile extending along its long axis, so that
four recesses are formed which are V-shaped in cross section. The
first compressed air motor is housed in a first recess, the supply
lines for the compressed air and the electrical control lines in a
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second and fourth recess The second compressed air motor for the
drives is housed in a third recess. The individual mQvements of
the robot 1 and the work performed by it can be continuously
monitored by the video camera 8 seated in the fork 10 and can be
controlled via the camera image by the supply and control unit
disposed above ground, which is equipped with an appropriate
monitor. The control unit even permits automatic cutting of
programmable cutting curves, which is of particular advantage when
cutting lateral junctions which are to be opened. If it is
intended to cut such a junction for the first time, or if one that
was closed is to be opened again, it is necessary that the conduit
wall of the conduit in which the robot 1 is located is cut as
exactly as possible along the inner contour of the joining
conduit. It is first necessary to locate the place to be cut.
This can take place visually, in cases where a previously closed
spot is to be reopened, by traveling along the estimated area of
the juncture and scanning it with the video camera. The
previously closed place can usually be recognized visually. In
those cases where the previously closed place cannot be found
visually, or in all those cases where a conduit is to join for the
first time, an ultrasound sensor is employed, which is mounted on
the cutting head. The reflected ultrasound signals are different
when they strike a conduit wall behind which a hollow place is
located, for example the interior of a joining conduit. Once this
spot has been found, it is drilled by the cutter 5 while being
monitored by the video. Then the cutter 5 is moved, starting at
the drilled hole, along two intersecting directions as far as the
respective stop. The cutting paths can be detected via
potentiometers. The control unit is equipped with an electronic
device which makes it possible to calculate the center and the
dimensions of the joining conduit on the basis of the cutting
paths traveled and detected by the potentiometers in the form of
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electrical signals, and to store them as data material. On the
basis of these data the electronic device can calculate a circular
cutting curve and subsequently can control the cutter
electronically in such a way that lt travels exactly along the
calculated cutting curve, because of which the said place is
cleanly opened.
An extruding unit 23, which can be installed between the
fork ends 11 in place of the cutting unit, performs the extrusion
of epoxy resin for the purpose of repairing or closing off a place
in the conduit at the end of the cutting work or after the
insertion of a pig has been terminated. However, the extrusion
unit 23 is advantageously embodied as an add-on piece which can be
placed directed on the cutting head 17 and fastened there by
screws, as can be seen in Fig. 6. The extrusion unit 23 consists
of a shoe 24, the shape of which is a section of a hollow
cylinder. Runners 25 are mounted on the rounded long edges of the
extrusion shoe 24. During working, these runners 25 rest on the
intact conduit wall on both sides of the place to be worked and in
this way act as spacers. The rear end edge of the extrusion shoe
24 is embodied as a special smoothing edge 26 which acts as a
smoothing trowel. The outlet opening 48 for the epoxy resin to be
extruded is located approximately in the center of the extrusion
shoe 24. On the back of the extrusion shoe 24 a nipple is
disposed around the outlet opening, on which the hose for the
epoxy resin is mounted. In use, the extrusion shoe 24, while
being monitored by video, is taken to the place to be repaired or
closed off and is then pressed against this place by extending the
cutting head 17. In the course of this the lateral runners 25 are
placed on an intact area around the place to be filled by
extrusion and define the position of the extrusion shoe 24. Now
the two components of the epoxy resin are pushed forward from the
supply unit by means of a pump located there, and are mixed
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directly prior to use and in place, so to speak, in an opposite
flow helical mixer 46, as will be described later. Once it has
- been determined through video monitoring that the injected epoxy
resin has sufficiently filled the place, the extrusion shoe 24 is
pivoted along its runners 25 approximately around its radius of
curvature by pivoting the cutting unit 4 or by rotating the fork
10 by means of the disk wheel 9. In the course of this the
smoothing edge 26 passes across the place filled with extruded
epoxy resin on the exact level of the runners 25 and thus on the
level of the surrounding area of the inner wall and cleanly
smooths out the epoxy resin.
An opposite flow helical mixer is illustrated in Fig. 7 in
a lateral view with a partially cut wall. This is a plastic pipe
46 with a diameter which slightly tapers toward the front. In the
interior of the plastic pipe 46 a row of rectangles 47,
respectively twisted by 180, is disposed so they adjoin each
other, so that their long edges respectively form a helical shape.
The individual twisted rectangles 47 or twisting elements 47 are
lined up with each other in such a way that the straight ends or
broad sides of the respective twisted rectangles adjoin each other
at right angles. The two components of the epoxy resin pushed
through the opposite flow helical mixer are turned by 180 by each
twisting element 47, and then each component is cut in two by the
front edge of the next twisting element 46 and brought tosether
- with half of the other component. Thus, on both sides of each
twisting element 47 two fresh portions arriving from the previous
twisting element 47 are freshly mixed. This process extends over
approximately ten twisting elements 47, because of which very
intimate mixing of the two original components is achieved. This
opposite flow helical mixer is disposed underneath the valve
, control unit 14. Thus, the finished epoxy resin mixture exits the
~' supply line 35 there and reaches the extrusion unit 23, by means
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of which the epoxy resin is applied~ to the place in the conduit to
be repaired or closed off.
The embodiment of the synchronous drive of the locomotive 8
is illustrated in Fig. 8. A row of toothed wheels of equal size
and in an uneven number, which transfer the driving force from the
drive shaft 44 to the other one, 45, is disposed between the front
and rear drive wheels 12, which are respectively connected with
each other via a rigid axle. By means of this type of power
transfer, absolutely synchronous running of the four drive wheels
12 of the locomotive 8 is assured without play and with the least
space required and most effective power transfer. Each of these
toothed wheels 29 is disposed on a separate plate 38 which, in
turn, is sealingly bolted to the housing 27. The entire gas-tight
housing of the locomotive 8 is filled with nitrogen at an
overpressure of approximately 0.2 bar in respect to the
environment in order to prevent any entry of moisture or water.
This overpressure can be regularly checked and replenished, if
needed, through a valve provided for this purpose on the
locomotive housing 27. The electric motor inside the locomotive
housing has a rated motor voltage of 60 V at 5 A current
intensity, for example. It is equipped with a tachometer
generator, which is coupled with a transformer and amplifier in
the supply and control unit. A voltage reduction because of an
rpm reduction of the electric motor is automatically compensated
for by the supply and control unit via the transformer and
amplifier with an increased current intensity in accordance with
an optimized characteristic curve based on the motor type. The
four specially developed solid rubber cleated tires 28, which are
provided with many rubber cleats all around the visible tire cross
section, assure the optimal power transfer of the locomotive 8 so
as to obtain as great as possible an adhesion to the curved inner
wall of the conduit through which it travels.
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So that the device can also be employed in conduits of
considerably larger diameter than those the inner wall of which
the robot, resting on the conduit floor, can reach, instead of the
runners the robot l can be equipped at two places additionally
with traveling gear legs which can be radially extended away from
it. These traveling gear legs can be extended pneumatically, for
example and can be arrested in any extended position by means of
pneumatically operated oil brake cylinders. In an advantageous
manner the traveling gear legs are equipped with free-wheeling
wheels in such a way that the robot 1 can be stabilized around its
long axis for work in the center of large diameter conduits and
still remains movable by means of the locomotive 8.
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