Re: Pressure Drop In A Vacuum Pipe
Dear Don,
Visit the following links:
Pneumatic conveying, Performance and Calculations:
https://news.bulk-online.com/?p=65
Dense phase- or dilute phase pneumatic conveying:
https://news.bulk-online.com/?p=238
Pneumatic conveying, turbo- or positive displacement air mover:
https://news.bulk-online.com/?p=309
Energy consumption per ton of a pneumatic conveying system:
https://news.bulk-online.com/?p=331
Moreover, especially this link, as it is related to your question.
Pneumatic conveying, an unexpected relationship.
https://news.bulk-online.com/?p=445
If you lengthen the vacuum pipe, the vacuum cannot be increased, because then the air mass flow decreases and the velocities become too low.
Choking will occur.
Lengthening the vacuum pipe requires a decrease in SLR (Solid Loading Ratio or capacity) to keep the vacuum constant at the maximum possible value.
Only a calculation can show the options in relation to pressure drop and capacity.
In addition, the type of material you are referring to as well as the vacuum source is relevant.
Based on the existing installation, a rather precise calculation is possible, using the performance data of the product.
With more information, a more specific reply is possible.
have a nice day
Teus ■
Teus
A Bit Simpler...
I’m actually looking for something simpler, I just need a basic approximation formula.
You have a long pipe like system with vacuum. If you extend the length of the pipe with all other parameters remaining constant, what is the loss in pressure, or will it rise?
Is there an estimate equation to calculate the pressure change?
Yours kindly,
Don Defy ■
Re: Pressure Drop In A Vacuum Pipe
Dear Don,
I made a calculation for a cement vacuum installation with different lengths and deived the power in your formule.
Suction length L1 = 60m
capacity 81.3 tons/hr at p1 = 4500 mmWC
Suction length L1 - 75m
capacity 81.3 tons/hr at p1 = 6228 mmWC
giving:
6228 = 4500 * (75/60)^alpha
alpha = 1.44
Not quite the 0.333 you used.
I am afraid that there is no simple rule for an unknown situation.
Take care
Teus ■
Teus
Cheers
Ill give that formula a go, thanks for your help ■
Re: Pressure Drop In A Vacuum Pipe
Dear Don,
I have to emphasize that this formule and the used exponent are totally insignificant for a random installation and working point!!!
The example that I gave is just to show this insignificance.
Do not base any decisions on the derived value!!!!
TAKE CARE
Teus
Giving actual information of the existing installation and operational data are more helpful to formulate a reply. ■
Teus
Pressure Drop in a Vacuum Pipe
Hi guys/ladies!
New here, so apologize if posted in wrong section ^^
I need to calculate a pressure drop in a vacuum pipe if the length is increased but the diameter stays the same.
Is this formula correct:
p2 = pressure drop after modification = p1 * (L2/L1)^0.3333
???
Is there a different way for calculating pressure drop in a vacuum pipe?
Regards,
Don Defy ■