Large Air Systems – Sales Training Abrasive Blasting
Learning Objective To educate the Doosan sales team and dealer sales force on the terminology and system layout for our blasting customers Provide a level of education to assist in the proper sizing of a compressor to support a blast application Share the list company partners that we should work on a local level with to assure we are talking to ALL the possible customers Enable our dealers to evaluate expansion of the line card to further support this customer segment
Abrasive Blasting System Blast Pot Compressor Dryer Nozzle Hose Operator
Value Chain Compressor Optional Dryer Blast Pot Hose Nozzles Media Dust Collector Or Reclamation
What to Look for – Bridge Work Sand Blasters Painters Coatings Contractors
What to Look for – Towers
Abrasive Blasting System Pressure Flow Moisture / Contamination
Abrasive Blasting System Pressure is dictated by: Media Hose length and diameter Flow is dictated by: Number of Users Hose Length Hose Diameter Nozzles
Media – Standard Applications Sand -100psi for jobs < 500ft2 (anything >500ft2 cannot be used) Slag (aka “Black Beauty) – 125psi Metal Shot – 150psi Also used in the cleaning and preparation of concrete. Application must tolerate potential ferrous residue. Round abrasive media that is extremely durable and dense Available with specific hardness, roundness, and size specifications as required for certain peening applications. This is the only media that can be recycled (up to six times). Glass Bead - Glass Bead blasting can be used on a wide range of materials including metal, glass, plastic and rubber. The smaller the glass spheres, the smoother the surface; Larger spheres produce a more textured finish. Soda - sodium bicarbonate based media (baking soda) is manufactured to be in a consistent, larger crystal size. When it strikes the material you are soda blasting the crystal explodes outward and the explosion is the force that strips your target of grease, paint, mold, dirt, whatever it is you are removing.
Media – Food Prep. / Organic Applications Dry Ice – 200 psi max Also known as Cryo blasting and Co2 blasting, Dry ice blasting is similar to sand blasting, plastic bead blasting, or soda blasting where a medium is accelerated in a pressurized air stream to impact a surface to be cleaned or prepared. Instead of using hard abrasive media to grind on a surface (and damage it), dry ice blasting uses soft dry ice, accelerated at supersonic speeds, and creates mini-explosions on the surface to lift the undesirable item off the underlying substrate. Walnut Shells - Walnut shell grit is the hard fibrous product made from ground or crushed walnut shells. When used as a blasting media, walnut shell grit is extremely durable, angular and multi-faceted, yet is considered a 'soft abrasive' and it can clean brittle surfaces without leaving scratches. It is suitable for cleaning metal, stainlessness, glass, ceramics, semi-conductor integrated circuit package lead frames, etc. Walnut shell blasting grit is an excellent replacement for sand (free silica) to avoid inhalation health concerns. Corn Cobs - Corn Cob blasting is recommended by the log home industry to open the pores of the wood, allowing oil based finishes to penetrate more effectively. Eliminates mold and algae All of the above are biodegradable and will not cause contamination.
Hose Length and Diameter - Pressure Loss Every fitting, hose, elbow, connection causes a loss in pressure Reduce the number of fittings Less chance for loss of flow / leaks Less pressure drop Pots consume ~ 5 psi Pressure drop in a hose is usually the biggest loss Use this website or the tables to estimate losses http://www.gates.com/industrial/pressure/airFlow.cfm With blast media present, multiply by 1.5 for horizontal runs to increase the losses Multiply by 2 for vertical runs Hose Diameter & Length CFM Pressure Loss 100 psi 150 200 1” x 50’ 180 3.8 2.6 2.0 210 5.0 3.5 2.7 240 6.5 4.5 3.4 270 8.1 5.6 4.3 300 9.9 6.9 5.3 Hose Diameter & Length CFM Pressure Loss 100 psi 150 200 2” x 50’ 600 1.3 800 2.1 1.5 1000 3.2 2.2 1.7 1200 4.5 3.1 2.4 1400 6.1 4.2
Flow Plan for a 15% Flow Reserve in applications Any compressor’s flow decreases 1.5% per 1000 ft elevation Sum of the pieces = WHOLE Add up all the demand requirements for flow Number of users Air Tools Nozzles Spray Guns Process Needs
Nozzle Charts – Air Consumption Example: 3 x #6 nozzles at 120 psi = 705 CFM (without reserve) Multiply by 1.15 for capacity margin to allow nozzle wear (810 CFM -> XP825WCU) Consume 4,425 lbs of media / grit … see next slide
Nozzle Design Basics What blast pattern do you want? Double Venturi Straight bore Tight blast pattern Smaller jobs such as weld seam shapping, grillwork, carving stone, cleaning handrails Venturi Wide blast pattern Increase in velocity up to 100% More productive Long Venturi 40% increase in productivity to straight bore 40% decrease in abrasive consumption Double Venturi Increase size of blast pattern Maintain the higher velocity Wide Throat Nozzle Larger pattern but trade-offs
Nozzle Facts and Wear Estimates This section is meant to educate everyone in the material, terminology, and factors important to this customer segment. Ask customers questions – pressure, type of nozzle, media - they love to tell you what works for them!
How it works? 110 psi + 0.5 + 5 + 19 = 135 psi 1) Calculate Flow Requirements 4 x #5 nozzles need (4 x 150 CFM) = 600 CFM 2) Calculate Pressure Requirements Need 110 psi at the nozzle per the media and user request. 10 ft x 2” Dia. Hose from compressor to the pot => .5 psi loss Pressure pots ……… avg. 5 psi loss 50 ft x 1.25” Dia Hose = Gates.com => 12.6 psi loss Air is entrained with media (horizontal run) Multiply by 1.5 for horizontal runs ….. 19 psi loss (if vertical, multiply by 2 ……. 25 psi) 110 psi + 0.5 + 5 + 19 = 135 psi Therefore, next largest size with that pressure is 150 psi product HP675 (marginal due to 15% flow margin rule of thumb) HP750 – The best choice.
Who do you call on? Sand Blasters Bridge Ship Yards Towers Ports Refinishing contractors Industrial Painters Chemical plants Food processing facilities