How to Select and Optimize Abrasive Blasting Equipment
How to Select and Optimize Abrasive Blasting Equipment
Agenda • Factors to Consider for System Selection • Optimizing System Performance Through Component Selection • System Settings for Maximum Efficiency
Factors to Consider for System Selection
Four Critical Design Components Portability Pressure pot and water tank capacity Media flow rate Volumetric air flow
Volumetric Air Flow Capacity & Control • Determined by the internal components that make up the blast circuit – Internal diameter of the piping – Geometry of the piping (e. g. , bends, tees, and reductions) – Air and blast hose connections – Main air regulator
Job Size • Large, high-production jobs or jobs with difficultto-remove coatings – 375 cfm or greater • Small jobs with detailed work or easy-to-remove coatings – 185 cfm or less
Media Flow Rate Capacity & Control Water pump Media flow control valve 7
Media & Water Storage Capacity Wet Abrasive Blaster (or modified sandblaster) Vapor Abrasive® Blaster VS. Water tank supplies water to the pressure pot – Some come with water tanks so you can refill after both water and media run out – High abrasive and water consumption. Check blast time before purchasing.
Example of media and water storage Graco Eco. Quip 2 EQm Dustless DB 800 • Weight (empty): 370 lbs. • Dimensions: 35. 1 "L x 25. 7" W x 47. 4" H • Media capacity: 300 lbs. of crushed glass • Water supply from garden hose connected to machine • Weight (empty): 427 lbs. • Dimensions: 40"L x 36"W x 64"H • Media capacity: 300 lbs. of media • External water supply needed
Portability • System weight and overall dimensions affect portability and efficiency • Select system based on the job size, job frequency, and job locations
Examples of small, portable units
Optimizing System Performance through Component Selection
Compressor • 115 – 185 cfm compressors: Ideal for small to medium-sized jobs • 300 cfm or higher compressor: Works well for large jobs
Blast Nozzle What blast pressure is required to prepare the surface effectively?
Blast Nozzle Throat • The throat dimension and geometry affects system performance, blast hose selection, and system settings, since it controls the maximum air flow at desired blast pressure. • Labeled or described by the throat diameter in 1/16 -inch increments Venturi nozzle Wide Throat nozzle Straight Bore nozzle Double Venturi nozzle
Blast Nozzle Blast Pressure • 25 -55 psi - Monument Restoration, Cleaning, Soft Stone, Wood, Aluminum, Restoration and Remediation, Efflorescence Removal, Graffiti Removal, Parts Cleaning • 56 -90 psi - Concrete Cleaning, Building Restoration, Line Stripe Removal, Pitted Paint Removal, Rust Removal, Loose Mill Scale Removal • 91 -120 psi - Concrete Surface Prep, Exposing Aggregate, Steel Surface Prep, Mill Scale and Coating Removal • 121 -175 psi - White Metal Blast to Near White Metal Blast, Tight Mill Scale Removal, Removal of Layered Coatings and Polyurea Removal
Blast Hose • The blast hose plays a simple, but critical role: transport air, media, and water to the blast nozzle • If Air Flow < 100 cfm use a 0. 5 -inch blast hose • If Air Flow 101 -300 cfm use a 1 -inch blast hose • If Air Flow 300 cfm > use a 1. 25 -inch blast hose
Media Abrasive size, commonly referred to in mesh or grit, affects blast equipment performance
Media • Smaller abrasive particles reduce the water-to-media ratio, since there is less space between the abrasive particles when pressurized in the system. • Larger abrasive particles increase the water-to-media ratio due to larger spaces between the particles while pressurized. • Example: If one quart of water per minute enters the pressure pot, one quart of water and media mixtures leave the pressure pot. – If a fine media is being used, the quart of mixture entering the blast stream will have a greater total mass, than if a courser media, since the abrasive is denser than the water.
System Settings for Maximum Efficiency
Three important components for achieving desired Blast Pressure
Blast Pressure • Tough, thick coatings require a high blast pressure • Easy-to-remove coatings require a lower pressure • Care should be taken when removing tough coatings off delicate substrates since the substrate can be damaged when the coating is removed
Blast Pressure + +
Five important components to achieve desired Abrasive Consumption Rate • • • Abrasive Meter Valve Set Point Blast Pressure Air Flow Air Velocity Abrasive Size and Density
Abrasive Consumption Rate • Maximum abrasive consumption rate does not always provide the best production rates and blasting efficiency
Educational Resources
For more information or to request a demo, visit Graco. com/ecoquip
www. graco. com/Eco. Quip
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