Patent Abstract:
In accordance with the invention, there is provided a concrete removing apparatus for removing concrete from an inclined wall of concrete having a frame with a front region. The frame may be supported on either a platform or from the wall with the front region adjacent to the wall. A carriage assembly is coupled to the frame assembly proximate 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 operative to move laterally of the frame assembly in response to activation of the carriage 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 carriage assembly.

Full Description:
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 jackhammrers. However, many concrete encased installations may not be compromised by the microcracks 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 operative 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 proximate 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 rotatable 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 assembly. 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  FIG. 3  supporting the hydrodemolition machine of  FIG. 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  15 A,  15 B and  15 C and vertical supports  17 A and  17 B, which together with elements  37 C and  15 C define a front region  39  of frame  12 . Inclined elements  35 A and  35 B, together with respective base elements  15 A and  15 B and vertical supports  17 A and  17 B, form a generally triangular shape on either side of the frame  12 . Short members  37 A and  37 B at the top of the structure join elements  35 A and  17 A and  35 B and  17 B, 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, can be slid 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 . Nozzle blocks  14  and  16  are each slidably mounted on guide bar  18 . An elongated threaded lead screw  20  engages threaded bores in each of nozzle blocks  14  and  16  and is journaled in block  19  and one end and is driven by an actuator  30  at another end. Nozzle blocks  14  and  16  are spaced apart a distance of approximately one-half the spacing of vertical supports  17 A and  17 B. Mounted on top of nozzle blocks  14  and  16  are nozzle jet assemblies  22  and  24 , respectively. Hydraulic actuators  26  and  28  are affixed to nozzle 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 nozzle 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. 
     Nozzle block  14  has a plate  50  rotatably attached as shown in  FIG. 2  by means of a shaft  52  passing through a center of nozzle block  14  and being affixed to an underside of plate  50 . Actuator  54  and shaft  52  can rotate plate  50  through a desired angle about axis  107 -which is parallel to a plane of the wall and perpendicular to the carriage assembly-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  anc, 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  FIG. 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  FIG. 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  FIG. 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  FIG. 1 ) and hydraulic actuators  26  and  28  (see  FIG. 1 ) are operated to position the nozzle assemblies the right distance from the wall  11 . Actuator  54  (see  FIG. 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.  FIG. 1 ) begins to move the nozzle 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  FIG. 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 mcunted 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  FIG. 2  can be replaced by a nozzle assembly  81  having three vertically spaced apart nozzles as shown in  FIGS. 5 and 6 . Referring to  FIG. 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 nozzle block  14  by bracket  68 . 
     Referring to  FIG. 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  FIG. 6 . The foregoing mounting arrangement also has the advantage of reducing the impact of the jets on the wall  100 . In  FIG. 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  FIG. 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  FIG. 8  allows a large distance of adjustment perpendicular to the plane of the front of region  39 . In  FIG. 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  FIG. 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  17 A to another vertical support  17 B. 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.

Technology Classification (CPC): 4