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US 4,081,200 AGranted
Method and apparatus to remove structural concrete
AssigneeFlow Industries, Inc.
InventorJohn B. Cheung
Life of this patent
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AssigneeFlow Industries, Inc.
InventorJohn B. Cheung
Estimating the term…
By the action of water jetted against the concrete in systematically controlled manner under ultra-high pressures (i.e. above 25,000 psi) areas of structural concrete are removed to required depths through the one or more levels of aggregate involved efficiently and with safety to the basic structure and to attendant personnel. With this method and apparatus employing an array of such jets scanned progressively back and forth over a work area, the rates at which requisite volumes of hardened concrete can be removed, regardless of condition or state of the concrete and the presence of reinforcing bars, are much greater than those customarily achieved with conventional methods. Moreover the operation can be performed without danger of cutting into and weakening embedded reinforcing bars, without damaging the concrete in adjoining regions, without dust pollution and with minimum noise levels that are also readily shieldable. The sequential penetrating and exploding action of the ultra-high pressure water entering between and beneath the aggregate particles not only removes the concrete immediately surrounding embedded reinforcing bars but is also effective to remove surface scale and corrosion from such bars, conditioning them to form a strong bond with fresh concrete to be poured around them. Moreover, incidence angle of the water jets to the concrete surface may be varied during scan so as to enhance the removal action in places otherwise difficult to reach, such as beneath and behind reinforcing bars or composites of such bars.
The method of removing from a concrete structure an area of structural concrete extending inwardly through levels of aggregate to predetermined depth, comprising directing against the concrete water jetted to impinge the same under pressure in the range above substantially 25,000 pounds per square inch in at least one or more separate impinging streams having an energy level created by such pressure sufficient to erode and remove the concrete to such depth, each such stream having a lesser cross-sectional width in any direction than the width of such area measured in said direction, progressively advancing each impinging stream across said area in concrete in a line of motion that removes the structural concrete impinged thereby first to a partial depth a minor fraction of said predetermined depth and thereafter to said predetermined depth preceded by removal of adjacent structural concrete substantially to said partial depth by such jetted water impinging the concrete adjacent to said line, whereby continued depth penetration and removal of said layers of aggregate at one location in said area is substantially paced by penetration and removal in adjoining locations so as to maintain openness around any such locations for escape of aggregate particles without substantially impeding the directness of such jetted water impingement on the concrete.
Apparatus for removing from a concrete structure an area of structural concrete extending from the surface thereof inwardly through levels of aggregate to predetermined depth, comprising a source of water operable to deliver water under steady pressure exceeding substantially 25,000 psi, nozzle means receivingly connected to said source and operable to jet the water under such steady pressure against the concrete in one or more steady impinging streams with an energy level created by such pressure sufficient to cut and remove the concrete by eroding it away to such depth, carriage means supporting and directing said nozzle means against the concrete and operable to effect progressive movement of the nozzle means in a manner systematically to scan said area by such jetted water impingement at a controlled rate and to repeat such scan so as to erode the concrete to successively increased depths over such area.
Dependencies are inferred from the claim text.