Hi Vani,

I dunno u r talking about turbo Blower or ordinary blower. If it is Turbo Blolwer you have to follow the NEMA otherwise u need not.

Dont consider any other bellow other than Pressure Balanced Bellow nearer to Blower discharge nozzle. Because enarmous forces would cause if u consider other bellows.

If it is ordinary Blower, simple bellow is more than enough, but provide proper guide before the bellow, so that to limit the lateral movements.