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Ventilation with fans issue


orzel

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Hello,

I need help with ventilation. I will explain briefly wht is the issue.

I have manifold (kolektor) to which a lot of small pipe connections are made (sides). Through these pipes fan 55kW is sucking the air and odour from some factory. This installation was working fine until new fan was connected at the end of the line. Now when this fan 37kW is working it is blowing the air to small channels. Fan 55kW is not able to prevent the air come to small pipes. 

I have think over this issue, and I found that solution (page2) that I will install 1 way valves (DN300 - zawór zwrotny). Do you think that this solution will work? The aim is to avoid backpressure in the side pipes. And at the same time it is necessary to suck the air from these pipes.

Then at 3 page I shown 1 side pipe which is connected to screw conveyor sucking the odour with air. It is necessary to regulate the air force sucking from this screw, so I found out that we can build new inlet of air just in case if the sucking force will be too big with some regulation valve.

Please tell me whether it will work? Thank you for help. Tomasz

 

 

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Edited by orzel
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Hi Tomasz,

I built a simple model of your system in Ventsim using a fixed power for the fans and estimating dimensions of your airways:

image.png.b8b97fb813f3c20be09ea927bbef7c10.png

I got the same result as you, that is the air is being forced out of the small diameter pipes due to the higher pressure in the manifold.  Using one way valves on these pipes would not solve this problem as the pressure inside the manifold would still be greater than that outside, resulting in no flow through the small diameter pipes.  The solution would be to go back to the original design without the 37kW fan or use a lower power fan if this is not possible.

Regarding the regulation of the pressure from the screw conveyor, having the regulator in the parallel airway will have an indirect effect on the pressure from the screw conveyor, however this could still be exceeded if other airways were blocked.  A better solution might be to install the regulator directly on the screw conveyor.

Hope this helps

Jason

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Hi Tomasz,

I adjusted the model based on your proposal and it should work:

image.png.4dfc7efb5d08e2c23c01bb8377276f82.png

However the 37kW fan would actually be working against the larger fan in this situation.  If it is possible for you to connect the 37kW fan intake to the manifold as in the model below then the two fans would be working in parallel to draw air out of the manifold, which would be a more efficient arrangement.

image.png.d47dc0ab9e20eead8e133fbe3ed2dad3.png

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