Can't get adequate solution flow in salt spray testMay 30, 2012
I'm a French student and I'm currently working on a salt spray device.
We bought this device from a Chinese company.
According to the European standard NF EN ISO 9227 [link is to spec at Amazon], we need to have a flow of 1.5 (+-0.5) mL/h into the measuring bucket, BUT we're really under this measure (approximately 0.3 mL/h)
We tried to increase the pressure and we also tried different heights with the dispersal cone but the result is the same.
If someone had the same problem and can help me, I would be grateful to you.
A. From experience and not from great knowledge, here are my thoughts--
First, replace the filter on the bottom of the atomizer tower.
Second, check that the holes in the unit are truly open. I chased my tail for days with a similar problem and by accident (while I had it apart testing each portion) I found that there was a tiny thin flap of plastic that with no pressure fit snugly to the wall, but with air flow would come up and block nearly half of the hole.
Third, check the actual volume sprayed to see if that volume divided by the surface area of the tank is adequate.
Fourth, set multiple catch devices in all of the allowed areas of the tank. Nearly all of will have heavier settling of the fog is select areas. A couple of inches can make a big difference, but normally it will be several inches. Use the allowed area of the heaviest "precipitation".
- Navarre, Florida
A. Hi Thomas,
Getting the collection rate correct is a balancing act of pressure, flow, atomisation and method of collection. With your very low collection rate the first thing to look at is that you have sufficient surface area of the collection vessels. ISO 9227 has a set surface area so check that you are meeting that.
If increasing pressure is not helping (and I really wouldn't expect it to help, it'll more affect the dispersion or atomisation of the spray) then you need to increase flow rate.
aerospace - Yeovil, Somerset, United Kingdom
A. Bonjour Thomas.
Comment allez vous?
I had similar problems with our salt spray cabinet, which is an old Harshaw model built in the 1980's.
What are your tower temps, pressures, cabinet temps? Are you using ASTM D1193 [link is to "Download ASTM Standards" from ANSI.org] Type IV water? One needs to use a good quality D.I. water source, with low TDS , uS as salts will clog the nozzle orifices (as you well know).
Since this is a closed loop system relying on pressure to feed the water tower and the salt vessels, inspect EVERY fitting to ensure there are no leaks / drips.
I went and gave old Betsy a complete overhaul, and found HAIRLINE cracks in some fittings, which when replaced produced more than adequate ml/h fog. I needed to close the vents somewhat
Also, the salt vessels are equipped with a 5 you poly pro filter, to ensure no particles can gain entry to the atomizers. Bon Chance!
- Toronto, Canada
A. I too had a similar problem with a Singleton cabinet and will present you with another possible solution. After weeks of fiddling, cleaning, and adjusting I determined that the angle of the atomizer to the bevel of the spray apparatus was off.Scott Merritt
- Eastman, Georgia, USA
A. Hi Thomas,
Better you can check the Funnel diameter for the collection, in general collection area should be 80 sq.mm, for this area you need to select the funnel diameter of 100 mm.
And keep one collection unit near nozzle & one is in end of the nozzle in the distance.
- Salem, Tamilnadu, India
A. I had a similar problem on a Harshaw (Auto Technology) cabinet. A thorough cleaning of the atomizer nozzle did the trick for me.Phil Brown
- Welcome, North Carolina, USA
September 17, 2012
Q. Hello, I wanted to know what is the flow rate used from the solution tank to the sprayer.
How to determine the flow rate from the solution tank to the spray?
Hope I get a response soon. Thank you.