Achieving Efficiency in Abrasive Blasting William P. Nelson Schmidt Engineered Abrasive Systems Sponsored by:

What is the Definition of “Efficiency”?  Abrasive blasting is defined as a controlled erosion process whereas your productivity is measured by how much area is blasted, in what time frame and by using how much abrasive

What is Abrasive Blasting?  “To combine the energy of compressed air with a granular abrasive, which is propelled to impact a surface in a controlled, repeatable and predictable surface preparation method.”

Enemies of any Air Blast System  Insufficient air supply  Moisture  Pressure drop

Enemy #1 Insufficient Air Supply  You lose 1.5% of productivity for every 1 psi reduction in blast nozzle pressure (As stated in research by NACE)

Enemy #1 Insufficient Air Supply NOZZLE No. 4 No. 5 No. 6 No. 7 No. 8 Orifice Size 1/4”5/16”3/8”7/16”1/2” 100 psi (All figures are approximate)

Enemy #2 Moisture  Increased operating costs  Increased material costs  Decreased operating efficiencies  Reduced productivity

Enemy #2 Moisture How does water get into the compressed air?  All air contains moisture  As the air is compressed, any moisture in it will also be compressed  As you compress the air/moisture, it heats up  Hot air retains moisture remaining a vapor So…How do you remove moisture?

Enemy #2 Moisture Convert moisture from a vapor to a solid (water droplets) HOW? By cooling the air you can then remove the moisture: ► By expansion (Moisture Trap) ► Use of radiator (ACS) Once the air is cooled, you have to separate it: ► Demister Pad ► Centrifugal ► Absorption / Adsorption

Enemy #2 Moisture 3” Air Inlet 1) 3” Outlet 2) 2” Outlet 4) 1” Outlet Aftercooler System

Enemy #2 Moisture 1500 CFM Air Compressor Water Volume in Air 75° Ambient Air 75% RH 270 gal./day 200°90° 90 Gal/day 180 Gal/day

Enemy #3 Pressure Drop  Nozzles  Hoses; Blast & Air  Restrictive Piping

Enemy #3 Pressure Drop

Nozzle Wear

Hoses & Set-Up

Enemy #3 Pressure Drop AutoAirValve

High-FlowAutoAirValve

Proper Set-Up

Difference of Control System Types PRESSURE HOLD NON-PRESSURE HOLD

Non-Pressure Hold System

Pressure Hold System

Fine Tuning an Abrasive Blast System Adjustments can be made to the following for enhanced productivity:  Abrasive metering  Minimizing pressure drop & increasing air flow  Hose length, hose size, couplings  Nozzle size  Moisture in air

Achieving Efficiency in Abrasive Blasting THANK YOU Sponsored by: