Assuming you are talking about replacement values then you will have to wet to the same conditions. So your water addition will have to be the same; easy.

Matching the manifold pressure to the solids flowrate is a little more difficult & entrails some knowledge of the spray patternation requirements; such as the lie of the coke in relation to the spray bar etc.

Modification is so simple; just change the inserts, shut down the air line & wind out the water control valve. If you don't get enough spread then speed up the pump & have another go. ■

JWillis is right. Highly atomised water will cause overspray on the walls of chutes and eventually, mud and blockages.

If your aim is moisture addition, you are best to use low pressure (250 kPa). Narrow angle flat spray nozzles allow you to aim the water at the falling ore stream and avoid wetting the chute and the edges of the belt.

It is best to add the total quantity of water at many application points rather than a few.

Michael Reid. ■

You should reduce the pressure to 200 kPa to avoid overspray. You can control the amount of water added by selecting nozzles with known capacity at that pressure.

Michael Reid. ■

Actually for dust suppression depends on how small water particles one is emitting from nozzle. As you wanted to switch to single fluid system, I would suggest you to reduce the pressure of water to 1.2 to 1.5 bar and air at 5.5 to 6 kg and see the moisture addition in downstream products before doing any modification because to suppress dust you need certain amount of water. ■

I apologize for straying from the subject but I would like to take advantage of the experts that have already posted replies to Mr. Sanjugun's questions.

My task is to lightly wet a belt at its edges by contact with twin cloth (wet brush) applicators. For the wetting of the brushes we need a very modest flow (drip) system. Of most concern is:

1.) the ability to know the flow rate precisely (a very low rate low pressure flow meter)

2.) the ability to finely regulate the flow

3.) the ability to interlock the flow with the need for it, that is, the flow will be cut off when the conveying rate falls to a low level (say 25% of design rate) and may increase somewhat when the the conveying rate is very high.

Can anyone guide me through such a system? Do all of these elements already exist as part of the typical fogger and dust suppression systems?

Joe Dos Santos ■

Joe,

Depending on just how low a flow rate is involved you could think about a peristaltic pump (Watson Marlow) running off a variable speed drive; itself reguated by the belt weigher signal.

Peristaltic pumps are precise enough for hospitals etc but the price is related to the pipe quality. For mine water it should be goood value & because of the pump precision & VSD there should be no need for a meter.

http://www.watson-marlow.com/ ■

John,

Thank you. This is helpful. Since the pump's setting will ensure the flow rate, the flow meter is not needed.

I have previously rigged temporary systems of this type from a tap water source, using hardware store hoses and valves. I was able to manually regulate the flow to the desired rate but did not know what the rate was. For this I needed a flow meter but could not identify such a meter. Additionally I could visually monitor the wetting, cut it off when it was not needed (at very low rates) and on again when the need resumed. Inerlocking the system to achieve this automatically (after manual tuning) is very important. I'll have to get smarter on the interlocking aspect.

Joe Dos Santos ■

Dear Sir,

Projects & Control has introduced COLDFOG- High pressure fog system which works without compressor. For details

contact: info@projectscontrol.com

Best Regards,

S. Ghosh

Executive-Marketing ■

We deal in several systems from 4 bar to 70 bar , the higher the pressure the smaller the droplet size, we also use rotary atomiser fan assited in many different applications ■