FIELD OF THE INVENTION

The present invention relates to a machine and a method of hydrodemolition for removing concrete from inclined surfaces.

BACKGROUND OF THE INVENTION

In many applications, where there is a need to remove existing concrete from vertical or inclined surfaces, particularly at elevated heights, it is necessary to attempt the removal manually with jackhammers. However, many concrete encased installations may not be compromised by the rnicrocracks such as those imparted by the severe mechanical impacts of a jackhammer. Hydrodemolition with high-pressure water jets would be ideal if there were a way of building a robot that could traverse the vertical or inclined surfaces. Attempts have been made to construct a vertical track over which a carriage supporting a nozzle with a high-pressure water jet travels. To speed up removal, two nozzles emitting water jets traveling together side-by-side across the carriage and back again were used. One problem that developed was the fact that less concrete is removed at the extreme of travel at either end because the second jet does not

overlap the path of the first at each such end. This means that the periphery on each side will be stepped. This step must be removed manually.

Another problem arises from the thickness of the wall. Typically, nuclear reactor concrete housings have a thickness of the order of 4 feet. A system must be in place that allows the nozzles to travel up to 4 feet perpendicular to the track in order to remove the entire wall thickness of material. In addition, to prevent the nozzle housing, which is larger in diameter than the nozzle, from contacting the edge of the opening, a shorter lateral distance of travel would be required for each pass or each of a set of passes. The net effect would be a side edge that stepped towards the interior of the opening with increasing depth.

Accordingly, it is an object of the invention to provide a hydrodemolition machine having water jet assemblies that removes concrete material from an inclined concrete wall at a faster rate than known methods and devices.

It is a further object of the invention to provide a hydrodemolition machine with water jet assemblies that can create an opening in a thick concrete wall that is vertical or inclined without steps in the sides of the opening.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided an apparatus for removing concrete from an inclined wall of concrete, having a frame with a front region adjacent to the wall and supported from one of the wall and a platform. The apparatus also has an elongated carriage assembly coupled to the frame proximate a front region thereof, the elongated carriage assembly extending across the frame. A nozzle assembly is mounted on the carriage assembly and is operative to move along the carriage assembly. A nozzle driving assembly is coupled to the nozzle assembly and drives the nozzle assembly along the carriage assembly. A nozzle on the nozzle assembly is o perative to emit a jet of water of sufficient velocity against the wall to remove concrete from the wall. A transporting assembly is coupled to and operative to move the elongated carriage assembly along the front region.

In accordance with the invention, there is provided a concrete removal apparatus having a frame assembly with a bottom and front region, the bottom region supportable on a platform with the front region adjacent to a wall. A carriage assembly is coupled to the frame assembly procimate a front region thereof, the carriage assembly extending from one side of the frame to another. A nozzle assembly is mounted on the carriage assembly and is operative to

move laterally of the frame assembly in response to activation of the nozzle driving assembly. A nozzle on the nozzle assembly is operative to emit a jet of fluid against the wall of sufficient velocity to remove concrete from the wall. A transporting assembly is coupled to and operative to raise and lower the guide and carriage assembly.

The front region is preferably rectangular and flat.

The nozzle assembly may advantageously be adjustable back and forth along its axis.

The nozzle assembly is mounted on a nozzle block that is pivotal about an axis parallel to a plane of the front region.

The carriage assembly includes an elongated guide bar that passes slidably through the nozzle block and is rigidly mounted on either end to end assemblies and a nozzle block motor and an elongated threaded rod driven by the nozzle block motor, the rod threadedly engaging the nozzle block and the nozzle block operative to move along the guide bar in response to rotation of the rod.

The transporting assembly may include a transport motor mounted to the frame and having a rotatable shaft and a pair of lifting mechanisms coupled to the transport motor and to respective ends of the guide and operative to raise and lower the carriage assemblies.

A pair of spaced apart nozzle assemblies may be mounted on the carriage assembly and be operative to move laterally of the frame assembly in response to activation of the nozzle driving assem bly. The nozzle assemblies move across respective halves of the frame assembly. A nozzle on each of the nozzle assemblies is operative to emit a jet of fluid against the wall of sufficient velocity to remove concrete material from the wall . A transporting assembly may be coupled to and operative to raise and lower the carriage assembly.

Rather than a pair, there may be a plurality of spaced apart nozzle assemblies mounted on the carriage assembly with the nozzle assemblies aligned along a direction perpendicular to the carriage assembly, and operative to move laterally of the frame assembly in response to activation of the nozzle assembly drivers, with the nozzle assemblies moving across respective halves of the frame assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the hydrodemolition machine with its

moveable carriage and two water jet assemblies;

FIG. 2 is a perspective view of the nozzle assembly for a single

nozzle;

FIG. 3 is a side elevation view of a platform elevated from ground

level used to support workers and equipment;

FIG. 4 is a side elevation view of the platform of Figure 3 supporting

the hydrodemolition machine of Figure 1 ;

FIG. 5 is a perspective view of a nozzle assembly having three

vertically spaced apart nozzles;

FIG. 6 is a top sectional view of the nozzle assembly with three nozzles blasting a concrete wall having reinforcing rod;

FIG. 7 is a schematic top view of a section of a wall within the swath of the top nozzle; and

FIG. 8 is a side elevation view of a nozzle assembly mounted on a rack and pinion gear system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to Fig. 1, for the sake of simplicity, the hydrodemolition machine 10 is shown without hydraulic, air and electric lines, water lines, various

frame elements and various other parts. Hydrodemolition machine 10 has a

frame 12 with a base 15 made up of base elements 15A, 15B and 15C and

vertical supports 17A and 17B, which together with elements 37C and 15C

define a front region 39 of frame 12. Inclined elements 35A and 35B, together

with respective base elements 15A and 15B and vertical supports 17A and 17B,

form a generally triangular shape on either side of the frame 12. Short members

37A and 37B at the top of the structure join elements 35A and 17A and 35B and

17B, respectively.

A carriage assembly 29 consists of guide bar 18 extending from one

side of frame 12 to the other and is mounted at one end in a block 19 which, in

turn, is slidable vertically with respect to frame 12. At the other end guide bar 18 is mounted to a plate 39, which also slides vertically with respect to frame 12.

Carriage blocks 14 and 16 are each slidably mounted on guide bar 18. An

elongated threaded lead screw 20 engages threaded bores in each of carriage blocks 14 and 16 and is journaled in block 19 and one end and is driven by an

actuator 30 at another end. Carriage blocks 14 and 16 are spaced apart a

distance of approximately one-half the spacing of vertical supports 17A and 17B.

Mounted on top of carriage blocks 14 and 16 are nozzle jet assemblies 22 and

24, respectively. Hydraulic actuators 26 and 28 are affixed to carriage blocks 14

and 16, respectively, and powered hydraulically, electrically or by air, drive

nozzle jet assemblies 22 and 24, respectively, along the length of respective

carriage blocks 14 and 16. Carriage assembly 29 is supported at either end by a

chain 36, which loops around a sprocket rotatably driven by shaft 34 and

actuator 32. Operation of actuator 32 causes carriage assembly 29 to be raised and/or lowered.

Carriage block 14 has a plate 50 rotatably attached as shown in

Figure 2 by means of a shaft 52 passing through a center of carriage block 14

and being affixed to an underside of plate 50. Actuator 54 and shaft 52 can

rotate plate 50 through a desired angle in either direction as shown by the double

arrow a-a. A second actuator 26 is mounted on top of plate 50 having a

threaded shaft 60 rotating in actuator blocks 27 and 58. Actuator blocks 27 and

58 are rigidly affixed to plate 50. A drive plate 56, affixed to a nozzle jet

assembly 22, threadedly engages threaded shaft 60 and, in response to rotation

of the latter, causes drive plate 56 and, hence, nozzle jet assembly 22 to move

parallel to an axis of threaded shaft 60. A similar arrangement exists for nozzle

jet assembly 24 (see Figure 1).

One important application of the hydrodemolition machine 10 is to

open a hole in a side of a nuclear reactor concrete wall 40 so that components such as a steam generator (not shown) inside may be replaced. As shown in Figure 3, the first task is to set up a platform 43 immediately below the proposed

opening. The platform 43 is supported by a number of steel elements 44, 46,

and 48. A debris catcher 42 is spread out beneath the platform 43 so that it is positioned to catch the concrete debris falling from the platform during operation.

As seen in Figure 4, the hydrodemolition machine 10 is placed on the

platform 43 with a crane and positioned so that it is lined up to begin concrete

removal. The carriage assembly 29 is lowered to the bottom of frame 12 (see

Figure 1) and hydraulic actuators 26 and 28 (see Figure 1) are operated to

position the nozzle assemblies the right distance from the wall 11. Actuator 54

(see Figure 2) adjusts the angle of the nozzle jet assembly 22 and a similar

adjustment is made for nozzle jet assembly 24. The water leading to the nozzle

jet assemblies is then turned on. At the same time, actuator 30 (see Figure 1)

begins to move the carriage blocks 14 and 16 sideways. Initially, only the region

around the center of the frame is cut by the water jets as the end regions are too far away. As the concrete in the center region is removed, the hydraulic actuators 26 and 28 (see Figure 1) are moved outwardly towards the wall to keep

the distance between the end of the nozzles and the wall constant. With each pass, the actuators are moved outwardly until the whole area planned for removal has been cut. An azimuthal adjustment provided by actuator 54 and a

like actuator mounted on carriage block 16 allows the nozzle jet assemblies to rotate and remove the same width of concrete without moving across the frame the same distance as in the first few passes. This allows the opening of a hole with a square edge.

Operationally, the nozzle jet assemblies 22 and 24 move across half

the width of the frame 12, after which actuator 32 moves the carriage assembly

29 incrementally, and the nozzle jet assemblies 22 and 24 return. This process

is repeated until the carriage assembly 29 has moved from the bottom all the

way to the top of the frame 12. The carriage assembly 29 could also move from

the top to the bottom of frame 12.

Optionally, the single nozzle shown in Figure 2 can be replaced by a

nozzle assembly 81 having three vertically spaced apart nozzles as shown in

Figures 5 and 6. Referring to Figure 5, in this case, hydraulic actuator 26

couples to a lead screw 62 that is threadedly received by block 66. A guide bar

64 slidably passes through block 66 and is fastened to carriage block 14 by

bracket 68.

Referring to Figure 6, in order to maximize the area of the swath 98 of

removed concrete, it is advantageous to rotate or oscillate the nozzles 86, 88,

and 90 about an axis that is at a slight angle to that of the nozzle housings 80,

82 and 84, causing the nozzles 86, 88 and 90 to wobble and the jets to cover a

wider area as shown in Figure 6. The foregoing mounting arrangement also has

the advantage of reducing the impact of the jets on the wall 100. In Figure 6, the

divergence of the jets of water 92, 94 and 96 have been exaggerated to demonstrate the averaging effect of the three jets when rotating or oscillating.

Referring to Figure 7, with three nozzles, in the event of indexing of the carriage assembly 29 in incremental movements equal to the spacing

between adjacent nozzles and in the direction of the arrow, it is necessary to be able to adjust the distance of each nozzle from the wall separately. This is necessary because the amount of concrete removed before impact by the nozzle

90 will be greater than that removed before impact by the nozzle 86. However, staggering the distance of each nozzle from the wall does require starting the

nozzle 90 first for the first pass, the middle nozzle 88 second for its first pass and

finally the lowest nozzle 86 third for its first pass. To accomplish the foregoing, it is necessary to be able to adjust the distance from the wall for each nozzle independently. It is possible to have all three nozzles the same distance from

the wall and to index the carriage assembly 29 so that the lowest nozzle is

positioned just above the previous position for the nozzle 90.

Mounting each nozzle on a rack and pinion gear system as shown in Figure 8 allows a large distance of adjustment perpendicular to the plane of the

front of region 39. In Figure 8, the exchanger and flow control valve assembly

101 are mounted to a rack gear 102 in a position in which the nozzle 106,

received at a distal end of the exchanger and flow control valve assembly 101, is directed outwardly towards a wall 108. Nozzle 106, during operation, emits a jet

110. At the opposite end of the nozzle is a hose 112, which brings pressurized

water to the flow control valve assembly 101. A pinion gear 104 has

circumferential teeth, which engage the teeth of the rack gear 102. The pinion

gear 104 is coupled to a hydraulic actuator (not shown). Rotation of the pinion

gear 104 causes the rack gear 102 to move linearly depending on the direction

of rotation of the pinion gear 104. The exchanger and flow control valve

assembly 101 controls the flow to the nozzle 106 and also causes the nozzle 106 to rotate.

Rather than using a chain drive to drive either end of the carriage assembly 29 up and down as shown by the arrow with two points in Figure 1 ,

one could also use a rack and pinion gear set on either side of frame 12.

There are other designs possible such as an elongated rail extending from one vertical support 17A to another vertical support 17B. The nozzle assemblies could each consist of a block with wheels, which engage and roll along the rail. A rack could extend along the rail on the back side from one end to the other. A motor mounted on the block could drive a pinion gear engaging the rack gear, thereby, moving the block along the rail. The nozzle and nozzle position adjustor are mounted on the block.

Although two nozzle assemblies each covering half of the length of the carriage and moving in synchrony have been described. However, obviously the nozzles could move independently along the carriage. Additionally, more than two nozzles assemblies could be used.

The carriage and frame element could be curved to conform with the curvature of the concrete wall. This would offer a slight advantage at the start of hydrodemolition since the whole length of the frame could be used to remove concrete.

While the operation of the hydrodemolition machine 10 has been

described as moving the carriage assembly 29 either down to up or up to down, obviously, the hydrodemolition machine could be designed to move from right to

left or from left to right with the carriage assembly 29 extending substantially vertically.

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 this 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.