Dear Shenjie,

Your equations apply to airflow only.

For pneumatic conveying this is not sufficient.

The energy, used for the conveying of the material can be divided in parts of which the most important are :

-velocity losses ----> lower at lower speed

-loading ratio losses ----> higher at lower speed

-suspension losses ----> higher at lower speed

The summary of the above mentioned 3 energies can be positive or negative, depending on the original conditions.

The same can be expected on the capacity change of the system.

Your approach was too simple.

( Your theory gives the maximum savings, when the pickup velocity = 0)

( 1 – 0%^3 = 100% saving)

Best regards, ■

Dear Shenjie,

If you are referring to your gas-only formals, you are right, but we are discussing pneumatic conveying, which has many more variables, influenced by the presence of material in the gasflow.

Check the used method of your calculation algorithm.

Success ■

Dear Shenjie,

Your equation is shown a bit distorted, but I can figure it out.

K is a material factor.

But R = (mass flow) / (gas flow) – ratio (loading ratio) is the key factor.

When you lower the gas velocity (using the same pipe diameter), the gas mass flow decreases.

Maintaining the same solids mass flow results in a higher (mass flow) / (gas flow) – ratio.

The higher loading ratio causes a higher pressure drop.

Now go back to my reply of the 28th February 2006 17.58

Have nice day ■

Dear Shenjie,

Your question "Is K remain constant when velocity changes?"

should be :

"Is K remain constant when loading ratio changes?"

From my answers you can learn, that in my opinion the product loss factor K increses with higher loading ratios.

(Also the Reynolds number influences the product loss factor, as it

is representing the turbulence of the flow)

Whether this is agreed by other members, this is a fundamental question.

You made that fundamental question clear.

well done. ■

Dear Shenjie,

In case you are referring to the conveying of PE pellets, I donot have any data or curves on this material.

Cement, fly-ash,alumina,grain derivatives etc. are the bulk commodities i have experience in

sorry ■