Mining or in situ disintegration of hard material – Processes – Breaking down by direct contact with fluid
Reexamination Certificate
1999-07-27
2001-05-01
Bagnell, David (Department: 3673)
Mining or in situ disintegration of hard material
Processes
Breaking down by direct contact with fluid
C299S036100, C239S172000, C239S251000
Reexamination Certificate
active
06224162
ABSTRACT:
FIELD
The present invention relates to a multiple jet hydrodemolition apparatus and method in which multiple hydrodemolition nozzles are operated to cover a greater area in a single pass than a unit with a single nozzle. The term hydrodemolition is sometimes referred to as hydromilling or hydroplaning.
BACKGROUND
Many concrete surfaces whether in parking lots, over bridges, on tunnel walls, building walls or any other concrete surface are frequently accompanied by heavy steel reinforcement. Once cracks in the concrete develop, road salts corrode the steel. This corrosion accelerates the destructive cycle of moisture, salt, freeze-thaw, corrosion, vibration and traffic. Conventional methods of repairing these concrete surfaces involves first the removal of the deteriorated concrete surface around and below the reinforcing steel bars. This removal allows placement of new concrete surface over the reinforcing steel.
Ordinarily concrete removal has been accomplished by jackhammers, but the use of jackhammers is time-consuming, and costly and makes it difficult to achieve complete removal of deteriorated concrete. In addition, the use of a jackhammer causes microcracking of the remaining concrete in surrounding areas. In order to improve the speed and efficiency of concrete removal from bridge decks, highways, substructures and parking garages and, at the same time, avoiding the problems caused by microcracking, contractors began using high pressure water jets to remove the concrete. The use of high pressure water jets, termed hydrodemolition, involves moving an oscillating or rotating nozzle back and forth across a bed for a number of passes and then indexing or advancing a vehicle on which the bed and nozzle are supported to a next position where the process is repeated until a desired depth of concrete deck surface has been removed. The removal leaves clean reinforcing rod which has been descaled but otherwise undamaged and a rough textured concrete surface under the reinforcing rod which is ideal for bonding of new overlay. All deteriorated concrete is removed and entrained chlorides washed away. There is a greatly reduced noise and no vibration or dust.
The conventional equipment used in hydrodemolition has one nozzle which runs over a guide bed and traverses a swath to be treated. After each pass the machine is indexed until a region has been impacted by one traversal. The vehicle is then reversed and the process repeated with the machine moving in indexes in reverse. Again once the swath has been covered the vehicle is moved forward in an indexed manner and traversals of the nozzle are repeated until the swath has been covered three times. Ordinarily three such passes are required to complete the hydrodemolition. Since the cost of a job is directly proportional to the time taken to accomplish it, there is a need for a faster more efficient method of applying hydrodemolition than that currently used. Some conventional equipment will complete a number of passes in a given position before being indexed forward where a like number of passes is then completed.
Accordingly, it is an object of the invention to provide an improved method and apparatus for applying hydrodemolition. It is a further object to provide a faster method of treating a surface with hydrodemolition than is currently in use.
SUMMARY OF THE INVENTION
According to the invention there is provided an apparatus for hydrodemolition having a movable vehicle, a fluid jet assembly having at least two nozzles, one behind the other, coupled to said vehicle and each oriented to direct a jet of fluid onto an underlying concrete surface, a bed coupled to the vehicle for guiding the nozzles back and forth transverse to a direction of movement of the vehicle, a fluid flow controller coupled to each of the nozzles from a source of high pressure fluid such that the fluid flow to each nozzle is independently controlled and means for moving the nozzles back and forth.
Preferably, the nozzles are one of rotatable and oscillatory and direct fluid at an angle to the vertical so that it can clean around reinforcing steel. Advantageously, the pressure of fluid supplied to each nozzle is independently controllable. Advantageously, a third nozzle is employed behind the last of the two mentioned above.
In another aspect of the invention there is provided a method of hydrodemolition which includes making a first transverse pass across a surface to be treated with a first fluid jet from a first fluid nozzle, and incrementing said first fluid jet forwardly and making transverse passes at each incremental position until a second nozzle reaches the position of the first transverse pass and then turning on the fluid to said second nozzle so that the second fluid nozzle impacts the same region as did the first fluid nozzle during the fist pass. Next the first and second nozzles are incremented repeatedly until the first fluid jet impacts on a last transverse pass after which it is turned off. The second fluid jet is incremented repeatedly until it reaches a position of the last transverse pass. After completing the last transverse pass the second nozzle is turned off.
Preferably, a third nozzle is employed behind the second nozzle.
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patent: 4854770 (1989-08-01), Puchala et al.
patent: 5022927 (1991-06-01), Seidel
patent: 5248095 (1993-09-01), Rankin et al.
patent: 5255959 (1993-10-01), Loegel
patent: 6010079 (2000-01-01), Mayfield, jr. et al.
patent: 3325909 (1985-01-01), None
Bose Vernon
MacNeil David
MacNeil Gerard
MacNeil Gordon
Bagnell David
Hall Priddy Myers & Vande Sande
Kreck John
Mac & Mac Hydrodemolition Inc.
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