WATERJET CLEANING OF TRUCK-MOUNTED CONCRETE MIXING TANKS

摘要

Manually removing hardened concrete from inside concrete mixing tanks using tools such as pneumatic chipping hammers has been identified by the National Institute for Occupational Safety and Health (NIOSH) as being a hazardous occupation. Engineers at NIOSH's Spokane Research Laboratory (SRL) teamed up with students from Gonzaga University to design an automated cleaning method for such tanks. The team built a prototype consisting of a remotely controlled lance with two opposing waterjet nozzles mounted on one end. The lance and its drive assembly are mounted on a control pedestal, which allows the lance to be adjusted for optimizing tank entry. The pedestal is supported and elevated by a scaffold-type frame. The system was tested using a 1,000-psi pump supplying up to 215 gal/min of water to the nozzles. It was shown that semi-cured concrete could be removed effectively from the tank walls. In cooperation with an industry partner, Central Pre-Mix Concrete Co. of Spokane, WA, the system will be demonstrated at a concrete mixing plant as a daily or weekly cleaner, and the results will be compared to current rinsing and cleaning methods. The goal is to reduce the build-up of concrete over time, thereby reducing or eliminating the need to chip concrete manually from inside the tanks.