The rule of thumb for dilute phase systems is 10:1 as a maximum. However, this can be less or more depending on your system layout.

For example, long runs might require a lower material to air ratio, while shorter runs might accept a higher material to air ratio. Also, if you have elbows that are configured back to back or with only a short straight distance in between this might require a lower material to air ratio.

We would be happy to look at your system and provide some input.

You can contact us at the email address listed below. ■

The maximum solids loading is the summary result of a number of variables simultaneously at work.

You can determine the maximum solids loading by plotting pressure against conveying velocity for your system. By incrementally reducing the conveying velocity you can find the point of minimum conveying pressure for a given solids conveying rate. It is at this point that the solids loading is at its highest.

Dennis Hauch ■

Thanks for the replies

I have some more information.

The conveying system is 300 Horz, 40 vert, 4 elbows

Material is Dog Food kibble. ( Finished pet food) 25 lbs/ft3

System capacity 70000 lbs/hr

Conveying Pressure Calculates to 10.5 psig

Pickup velocity 2900 ft/min terminal velocity approx 4500 ft/min

Ratio Required is Approx 16 to 1

Can anyone prove that this system will work or absolutely won't work ?

Thanks

Ross ■

Sir,

the conveying has to satisfy a kind of compromise between the solids throughtput, the air flow and the pressure drop.

So quite difficult to say that there is a maximum in pressure drop in dilute conveying for a given layout.

I would be much more concerned by not attriting the pet food and consequently be safe , gentle on the air velocity.

I may even try to add you may optimize the layout.

Best Regards,

Pierre ■

Mr Agarwal

If I increase the Froude Number do I not decrease the Product to air Ratio? It seems that there must be a point where the Ratio is at a Maximum. How do I find this Maximum?

Ross ■

Sorry It took me so long to reply

Away to Russia

I have read Dr. Klinzing book and Know Dr. Klinzing, I have hired a couple of his students over the years.

I still can not find a practical limit to the equations that fits what is found in the test lab or in the field.

Anyone ever tried to test the equations limits??

Ross ■