Using 2 dust collectors in parallel

[Scot wolf]

I'm sure I'm not the first guy to think of rigging 2 collectors in parallel. I have a 2hp Grizz and a 1 1/2hp Delta w filter. I was thinking of mounting the blowers on the ceiling side by side and connecting the 6" outlets on them into a 8" line. Then reducing down to 6" at the machines. I need a low cost solution for more suction.

[Michael W. Clark]

Volume adds when connecting two fans in parrallel. This is usually done with two identical fans. It is possible you will not get the full benefit of the added volume of each fan since one fan is smaller. However, the parrallel combination should provide more flow than either of the individual fans alone. The maximum SP will likely be determined by the 2HP Grizz.

Mike

[Dick Thomas]

Not a good idea, Scot. The 2 will fight each other, to the point that the more powerful may pull backwards through the less powerful. Blowers in parallel are extremely tricky to design and balance, and rarely succeed unless they are identical, matched units. Without perfect balancing you can end up with pulsing in the ducts, which can damage many components. I've seen it happen in an industrial setting, and it was not pretty. And, with mis-matched blowers, the maximum static suction you can achieve - i.e. the motive force yielding cfm capacity at any single point - will be the static capability of the less powerful blower.
Since you already have the units, the better approach is to divide your shop into 2 zones, each sized for the capacity of their respective blowers. An added benefit is that if the 2 zones are carefully planned, so that you will usually only be using the machines connected to a single zone, you have reduced noise levels, and energy use.