A major manufacturer of truck bodied cranes had an application for plasma cutting of heavy steel plate ranging on size from ½” to 1 ½” in thickness. A dust collector was sized for the plasma table manufacturer’s recommended airflow; and because it was a new process and equipment, actual dust loading levels were estimated.
The original dust collector initially functioned well with the original filters expected to last approximately 12 months. However, when full production began after a 4-month ramp-up in production, it became evident that the filters were not sufficient to handle the extremely heavy inlet loadings. A process change to coating the bare steel with a rust preventative created a situation that finally pushed the filter life into an unacceptable range. Due to the new adhesive nature of the smoke and dust particles, the stickier particles were reducing the filter cleaning effectiveness and the filters were lasting now only 3-4 weeks.
After numerous attempts to change the media and revise the filter pulse system, the customer and Air Purification Inc. decided to replace the existing collector with a Micro Air Model RP8-4 with the Intellitouch control system. With the new system, the airflow available to the plasma table was increased from the initial 3800 CFM to 4900 CFM for better smoke scavenging. All existing table ducting and spark dropout chambers were functioning well and were retained.
Air Purification Inc. removed the old collector and installed the RP8-4 with a new fabricated inlet header configuration. The equipment change-out was accomplished in approximately 1½ days, without interrupting the manufacturing production schedule. The Intellitouch system allows the airflow to be user-adjusted for maximum efficiency, and then be held at that level as the filters load by gradually increasing the fan RPM to compensate. Target filter life for the new dust collector was a minimum of 3 months. After 8 months, the RP8-4 filters were still providing the increased airflow for complete capture of the plasma smoke.
Plant air quality has been greatly improved by the switch to the RP8-4 collector and unscheduled maintenance issues have been reduced to zero.