| Abstract Scope |
Introduction:
The Weld Vac system can reduce the cost and increase the safety, productivity, and environmental quality of metal removal. An alternative to Carbon Arc Gouging (CAG), “WeldVac” is an advance in the removal of welds and other metals. WeldVac can have enormous impact on ambient environmental quality by virtual elimination of spatter, slag, fume opacity, carbon dust, and noise. In addition, substantial cost reductions may be achieved by the reduced amount of “area protection” that now must be placed on everything within 100+ feet of CAG operations. Further, other trades and jobs may be performed nearby due to the quiet and clean nature of WeldVac.
Synopsis:
At present, CAG is for weld and other metal removal, requiring extensive protection of large areas, and rendering work areas virtually uninhabitable for other workers. CAG generates huge quantities of hot slag that may start fires. CAG leaves debris that takes time to clean up. Even after cleanup, CAG operations typically leave residual carbon dust that could foul electronic and other equipment. WeldVac uses a capture device that traps the particulates and fumes. This project will provide objective validation of this and demonstrate WeldVac productivity, facilitating implementation.
The Weld Vac System offers these features:
• It may be entirely possible to eliminate 75% of the labor and materials for “protection” that now must be used to prevent damage to adjacent equipment when CAG is performed.
• Significant schedule improvement may accrue. Adjacent operations may be performed due to the quiet and clean nature of the process.
• WeldVac is QUIET - Other operations may proceed nearby. WeldVac tests proposed are expected to demonstrate sound levels below OSHA noise limits. The noise contribution of this process is anticipated to be below 90 dBA at the operator work area. Hearing protection may not be mandatory for WeldVac. Certainly, hearing protection may in many cased be mandated by other adjacent metalworking operations or company policies.
• WeldVac produces no hot slag and very low levels of smoke and fume. The level of fume generated by WeldVac is expected to be below existing opacity limits, allowing work to be performed efficiently by all other adjacent operations, with little need for respirators (unless mandated by other operations or company policy).
• Cost of cleanup may be reduced due to capture of nearly all slag and dust.
• High-pressure air supply is not necessary.
Experimental Plan:
The testing is set up to document the features and characteristics of the Weld Vac system using objective testing methods and professional experts in the fields of metal operations and industrial hygiene.
The following will be performed:
Determine performance testing joint designs, positions, and requirements
─ Identify procedural boundaries (i.e., weld sizes, methods, etc.)
─ Determine the parameters to be tested (noise, breathing zone, fume generation, productivity, etc.)
─ Determine metal removal rates (e.g., lb./hr. or linear fpm of fillet weld)
Perform initial WeldVac trials to determine modifications to test plan
Develop parameter sets for fillet and/or other weld removal scenarios that meet needs ─ Determine suitable parameters and weld removal sequencing
─ Identify shipyard-friendly procedure aspects
─ Perform appropriate environmental tests for the shipbuilding materials of interest
Determine removal rates, heat inputs, and other data to inform a clear business case analysis
Demonstrate the WeldVac methods at a team member location
Document the results achieved
Results and Discussion: Previous work has found that Weld Vac provides significant productivity and safety improvements over CAG procedures in use at present, but these results are only qualitive and anecdotal. The project has developed objective data to validate these observations, and may be used for further application of the methodology.
Acknowledgements: This work has been funded by the NSRP and completed in cooperation with Vigor Shipbuilding. |