When we use backward or forward curved blade of Impeller in Induction Draft Fan?

[rizawana]

When we use backward or forward curved blade of Impeller in Induction Draft Fan?

Please Help...

 

[MacGyverS2000]

Are you pulling or pushing the air?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[electricpete]

I always thought Induction Draft meant pull from a vacuum and Forced Draft means push to a positive pressure

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(2B)+(2B)' ?

 

[rb1957]

does "backward" or "forward" depend on the direction of rotation ... clockwise or CCW ?

another day in paradise, or is paradise one day closer ?

 

[Compositepro]

It is easiest and cheapest to direct couple a fan to the motor shaft so the fan must be designed to work at about 1700 rpm. Forward inclined impellers will produce a much greater velocity flow than backwards. Higher velocity means more pressure potential, higher power, and more noise. Backward inclined are quieter, use less power, and will have to be larger to get the same flow. There is no difference in "push" vs. "pull" between the two types. A fan can only push. You cannot pull a gas, as it has no tensile strength. Gas entering a fan is pushed into the fan by the higher pressure gas outside the fan, and thus approaches from all directions equally. Gas leaving a fan has momentum and will keep moving in the same direction until it mixes and diffuses.

 

[MintJulep]

You can get some good information from fan manufacturers.

One example:

https://www.chicagoblower.com/resources/fan-engineering-guide

 

[rizawana]

DEAR FOLKS...THANK YOU FOR YOUE VALUABLE REPLY...!!!



ROTATION IS ANTICLOCKWISE AND PUNLLING AIR FROM BOILER CHAMER TO CHIMNEY WITH FORWARD DIRECTION OF ROTATION.