US Patent 7587842 Method for storage tank demolition

A hydraulically-operated ripper tool is mounted as an attachment on a hydraulic arm of a carrier or excavator and used in a method for demolition of large metal walled structures such as storage tanks in a very short time. The ripper tool has a concave, sharp inner edge and is operated by the hydraulic aim in reciprocation so as to provide a shearing force to cut quickly through metal walls in “can-opener” fashion. The ripper tool is employed for making long vertical cuts into the tank wall from top to bottom, so that a series of vertical cuts can be made to weaken a side of the tank and allow the top of the tank structure to be brought down.