ARMEXTM Blast Cabinet

Transcription

1 William F. Stinson, Jr. 469 North Harrison Street Fax ARMEXTM Cleaning and Coating Removal Process Environmental and Productivity Benefits in the Aerospace Industry I ARMEX@ Blast Media I a 0 U' Li u' u II J ARMEXTM Blast Cabinet Figure 1 Components Comprising ARMEXTM Blast Cabinet Process 1

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3 ~ ~~ ~~- ~ ~~ ~ Control # 19 William F. Stinson, Jr. 469 North Hamson Street Fax PHYSICAL CHARACTERISTIC Soft abrasive, measuring 2.5 on MOHS hardness scale BENEFITS TO CRITICAL COMPONENTS Can clean without substrate damage, crack closure, or distortion from a variety of alloys and metals including those with hard anodized coatings Water soluble Non-toxic and non-hazardous per OSHA and EPA regulations. It is even USDA accepted as an A-1 cleaner. Virtually eliminates risk of passageway blockage. Simplifies waste treatment (see next item). Can separate insoluble materials for easy disposal while water soluble spent media can usually be discharged to drain'. Provides superior worker and environmental safety profile. It is a soft abrasive that can clean and depaint. Can clean and remove many coatings including grease, corrosion, oil, carbon, paint and gasket materials. Single use media 'Check regulations governing waste disposal I will not recontaminate critical components. ARMEP Cleaning and Coating Removal Process Environmental and Productivity Benefits in the Aerospace Industry 3

4 Control # 19 William F. Stinson, Jr. 469 North Harrison Street Fa '6 ACCUSTRIP DELIVERY DEVICE The benefits of ARMEX Blast Media can only be reaped if the media is delivered (blasted) at ideal pressures and flow rates, thus the need for the ACCUSTRIP SYSTEM Delivery Device. This delivery device differs from conventional abrasive blasting devices in that it has been developed and patented to deliver ARMEX media at very accurate flow rates ranging from 0.5 lbs/min to 3 lbs/min. Again unlike hard abrasives, ARMEX Blast Media does not necessarily yield increased productivity with more and more media per minute, therefore the delivery device must be accurate enough to obtain the best flow rate for the specific application. In addition to flow rate, the ACCUSTRIP SYSTEM delivery device is designed to precisely control the blasting pressure to ensure the proper sensitivity to meet the requirements of various substrates. A1 of these blasting parameters can be performed wet or dry to achieve a variety of surface finishes. ARMEX'"B1ast Cabinet System The most recent development in this cleaning process is the ARMEX blast cabinet which offers a unique method of containing the blast media while providing many other attributes, primarily unimpeded visibility of the component being blasted. Due to the friable characteristic of ARMEX Blast Media, using conventional dry blast cabinets is extremely difficult because a cloud of dust is created, severely restricting the operators vision, while quickly overloading conventional dust collectors. Water can be added to reduce dust, however this creates a "Fog" producing poor vision and a slurry of spent media which is incompatible with conventional air handling systems. Because of these significant problems, the ARMEX Blast Cabinet System was developed to provide an integrated system approach to the blasting process. The Blast Cabinet System is made up of three integral subsystems, the High Visibility Viewing Technology (HVVT), the air handling system and a waste filtration system. Hieh Visibility Viewing Technology To overcome the difficult problem of visibility while wet or dry blasting, a novel approach was developed. It incorporates a high velocity air stream through a purge chute directed toward the component being blasted. The blasting operator views the working area through the adjustable purge chute, where the air velocities through the chute have been measured in excess of 2500 feet/minute providing an unimpeded viewing zone or a viewing area free from blasting dust or mist when wet blasting. This High Visibility Viewing Technology is encompassed in US Patent Number 5,172,911. ARMEXTM Cleaning and Coating Removal Process Environmental and Productivity BenefIts in the Aerospace Industry 4

5 Control # 19 William F. Stinson, Jr. 469 North Harrison Street Fax Air Handling System The closed loop air handling system provides a means for removing or substantially reducing the dust particulate from the recirculating air stream, while minimizing the input utility power requirements. This is necessary to meet the visibility requirements at the purge chute and the air emission requirements of the exhausted air. Airborne dust particulate generated from blasting is removed (scrubbed) from the recirculating ventilation air stream by a Roto-Clone type wet scrubber. The contaminated air is drawn by vacuum into the scrubber and around a static mixing impeller set in a sump. A critical water level is automatically maintained in the scrubber sump to insure that approximately 99.6% of the airbome particulate (larger than 10 microns) is removed from the air stream. A small amount of air (approximately ZOO cfm) is diverted by an adjustable damper to a secondary air filter, then vented out of the cabinet. The system contains some active controls such as indicator lights and gauges which advise the operator of system status or to perform routine maintenance. Additionally, interlock mechanisms prevent startup or initiate shutdown during improper operating conditions. Waste Filtration System The waste filtration system further utilizes the water soluble non-toxic, non-hazardous benefits of ARMEX Blast Media, by soldilizing the spent ARMEX media then filtering the insoluble residues. The waste filtration system includes a 60 gallon tank, where the blast process residue and the scrubber make-up water drain via gravity. When the tank level reaches mid-point a level probe automatically activates the recirculation pump which mixes and dissolves all of the spent media. When the tank reaches near capacity, a second level probe automatically opens a drain valve allowing a portion of the waste stream to pass through a coarse bag filter and a fine cartridge filter to a gravity drain. Flow control valves allow the volume of waste to be balanced for a maximum dissolution time in the tank prior to filtration. Also included in the waste filtration system are active controls such as indicators to advise the operator of system conditions and senrice requirements. Interlocks supplement these controls to prevent start up or initiate shutdown under improper operating conditions. ARMEFM Cleaning and Coating Removal Process Environmental and Productivity Benefits in the Aerospace Industry 5

6 Field Experience Control # 19 William F. Stinson, Jr. 469 North Harrison Street Fax Several aeromace comdanies have demonstrated that the ARMEX Blast Cabinet Process A A (ABCP) can help them meet their pollution prevention program goals while attaining higher productivity and quality gains in rebuilding, restoring and maintaining critical components. AlliedSigna1 Aerospace Two of AlliedSienal., Aerospace s facilities, which overhaul commercial aircraft components such ~ as cooling turbines, main engine starters and pneumatic valves have recently installed the ABCP to clean many of these components. The ARMEX process replaced the previous cleaning method of alkaline soap and hot water combined with hand scrubbing of components. This hand scrubbing method was an interim alternative to chloro-flurocarbon (CFC) degreasers and resulted in satisfactory results but raised whste disposal concems. The facilities were interested in minimizing process waste and complying with increasingly stringent federal and local environmental waste disposal without sacrificing cleaning and performance efficiency. For these reasens the engineering department conducted a comprehensive evaluation of alternative cleaning technologies and waste disposal options, including an ultrafiltration and ph manipulation system for oil removal. The results of this evaluation convinced AlliedSignal to select the ARMEX process with dual nozzle configuration for cleaning small and large components. The process can clean dirt, oil, rust, surface corrosion, carbon and grease residue from components ranging in various sizes. The majority of components cleaned are hard anodized-coated aluminum with the remaining being titanium or stainless steel. AliedSignal operates the ABCP daily win a wet blasting at 20 psi which has resulted in numerous benefits. The aircraft parts are c ecked by visual inspection and are noticeably cleaner without any surface distortion. Productivit has improved; previous1 two workers on each of two shifts manually washed the components yie r ding a day and half backlg of arts to be cleaned. With the new ABCP, one worker per shift cleans the arts eliminating the acklog. In addition, less maintenance is required on the rocess, only one R our per week. The integral waste filtration s stemcaptures insoluble materials P or easy disposal while the remainin effluent is discharged to e on site waste treatment facilit for final disposal. Finally worker salty has been enhanced t r,. because the non-toxic, nonhaearius ARMEX Blast Media eliminates the need to handle the previous caustic cleaners, alkaline soap as well as some harsher rust and corrosion removers. \ ARMEXTM Cleaning and Coating Removal Process Environmental and Productivity Benefits in the Aerospace Industry 6

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9 Control # 19 William F. Stinson, Jr. 469 North Harrison Street Fax CO- Authors : Ken Colbert, Jim Shank, Biu Spears 469 North Hamson Street tel, fax Scope: Several aerospace facilities, such as American Airlines, Kelly AFB and Allied signal have had tremendous succeas in eliminating solvents while utilizing the ARMEX process. The paper ARMEWM Cleaning and Coating Removal Process Environmental and Productivity Beneflta in the Aerospace Industry 9

10 Table 3 AEROSPACE COMPONENTS BEING CLEANED BY THE ARMEX BLAST PROCESS Flat track bolts Jack screws Air cycle machine Scroll housing Impellers Axle shafts Veins Diffusers Deswirlers Thrust reverser clam shells Thrust reverser cascades Flap gear boxes Nozzles Transmissions Linkages Turbine Wheels Turbine Nozzles Turbine Shafts Valve Bodies Valve Butterfly Plates Air Bearings Main Engine Starters Auxiliary Power Unit Inlet Plenum Auxiliary Power Unit Exhaust Pipes Electric Fans with Stators 10

11 Aerospace Components Cleaned with ARMEFM Blast Cabinet Process Before and Mer Photos Figure 2 11