Blower Inlet Transition Size Question

[machine85]

I am retrofitting a replacement blower to an existing ring dryer to accommodate some increased airflow requirements. I have calculated the system static and flow requirements and have selected a blower that matches. (38" WC at 18,000 CFM) The question I have is regarding the inlet flange (suction side) on the blower which is 30" ID, vs the existing duct size which is 20". I wasn't sure if there were any issues with fabricating a transition piece to match these dimensions. The manufacture has recommended a 10X diameter length of the transition to minimize any system effects, and otherwise says would not be an issue with airflow or otherwise.

Other fans I considered met the same requirements but had the fan inlet ranging at 21" - 23" ID, but these were significantly more costly, so I would like to use the other unit with the larger inlet.

Just thought I would get a sanity check from anyone with more experience than I on this. Thanks.

 

[chicopee]

You also have the same post in the ME forum. Double posting is not in the best interest of the inquirer.

 

[Drazen]

yep, with 10 diameters transition you should not have trouble with system effect, you need to add "ordinary" pressure drop of transition peace to your pressure drop calculation, recheck working point, and that should be it (if there are no other troubles you did not mention).