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原文传递 IN-DEPTH SURVEY REPORT EVALUATION OF AN AUTOMATED ABRASIVE BLASTING MACHINE

题名：	IN-DEPTH SURVEY REPORT EVALUATION OF AN AUTOMATED ABRASIVE BLASTING MACHINE
作者：	Aian Echt
关键词：	evaluation；bras；blast；abra；sting；report；dept；chin；mach；mate
摘要：	This site visit was part of a project to determine the feasibility of using automated paint-removal technology on steel structures (ships, bridges, storage tanks, etc.). The major goal of the project was to determine the current status of the technology. This involved determining the number of prototypes currently available, the development stage of each prototype, determining on which steel structures each prototype can be used and the percentage of each type of structure on which the automated technology can be used, and a comparison of costs of the automated method with traditional methods of lead-based paint removal. Observation of prototype systems in operation was a critical component of this project. The system evaluated at this site incorporated the Pittman Vacuum Blasting Sytem (PVBS) Vacuum Abrasive Steel Cleaning and Reclamation System. This system included the blast head, a trailer housing the cleaning and reclamation system, an electric winch, and a hand-held controller. The PVBS marine vacuum blast head demonstrated on the ship Quest's superstructure during the NIOSH site visit consisted of two conventional abrasive blasting nozzles connected via blast hoses to the blast pot. The nozzles, located 18 inches apart, travelled inside the blast head on a slide mechanism which moved back and forth driven by an air cylinder. Reed switches which sensed the magnetic piston inside the air cylinder controlled the stroke of the nozzles. The blast head rode over the surface of the superstructure on rubber skirts. The head was held in intimate contact with the hull surface by the force of the vacuum, however, some leakage of abrasive and debris was noted during the demonstration. A newer model, which incorporated three blast nozzles and an improved seal was scheduled to be delivered after the demonstration. The top and bottom skirts rode on skis to allow them to travel over obstructions. Blast media, rust, and paint were mostly contained within the tool and immediately vacuumed to the cleaning and reclamation system. A variable speed electric winch allowed the blast head to travel up and down the hull at the rate required to achieve the desired finish. A single pass cleaned the tested portions of the superstructure to a white metal finish. Observations and air sampling data indicate that the PVBS automated blasting tool effectively removed and contained lead-based paint during the demonstration on the Quest, While the NIOSH researchers observed some paint chips escaping from the ship-to-tool seal, either the particles’ size, prevailing winds, or other conditions prevented them from reaching the breathing zones of the tool’s operators. Since this demonstration, both the tool and the seal have been modified, so that this leakage may no longer be a concern. It would be interesting and worthwhile to repeat this evaluation during the operation of the PVBS automated blasting tool in its current configuration over several complete work shifts during a lead-based paint removal project.
报告类型：	科技报告