Connecting Two Cyclones

Coupling two dust collection fan units together boosts the static pressure if you connect them in series, and boosts the airflow if you hook them up in parallel. August 24, 2008

I am thinking about hooking up two 5 hp cyclone dust collectors in order to increase the ability to overcome static pressure. Is this doable? From a cost perspective, I can purchase the two 5hp units for quite a bit less than a single 7.5 hp unit.

There are a number of ways of doing this. I could have both cyclones very close to each other, both connected into a length of ducting which would act as plenum. This seems like the most straightforward way.

A single 5 hp cyclone does a great job on one machine, but performance goes down with two machines. Two cyclones hooked together should be able to run pretty much everything in the shop simultaneously. I'm sure I'm missing something. I'm sure that a bigger fan on a big cyclone with a 10HP motor is a much more efficient configuration, but it is also priced at 3 to 5 times the price of my proposed configuration. Any advice is appreciated.

Forum Responses
(Dust Collection and Safety Equipment Forum)
From contributor A:
I think it would be simpler to divide your ductwork between the two cyclones. Have one cyclone hooked up to two or three machines and the other hooked up to the remaining pick up points.

Or you could stick with one cyclone and build yourself a distribution valve in between the connection of the main duct line and the cyclone where you open the line to one machine and close off all the others so that the cyclone works only with the machine you are working on.

If you really need to have a cyclone running all pick up points at once you need to calculate the cfm required first to see if this is doable.

From contributor W:
If you want to use two collectors to overcome static pressure problems, then you will only increase the static pressure of the system by putting the collectors in series rather than in parallel. Putting them in series adds the heads (static pressure) of the two fans. Putting the fans in parallel will increase the flow of the system (cfm), but not the static pressure.

From the original questioner:
Now that you say it, it seems obvious. I'm still in the process of laying out the shop and it's simpler to have two independent systems powered by two cyclones then to try and combine them. Much of the time, only one or the other would be needed, and there would be no reason to increase the noise level and power consumption to run two cyclones at the same time.

From contributor B:
I'm curious as to why your cyclones are not handling two machines simultaneously. Which model 5hp cyclones are you using, and, what size is your main? I would think that a 9" main, handling two 6" machine-ports, would offer a nice low-resistance set-up, with good velocity in the main, and decent collection at each machine. An 8" main may be too restrictive with that scenario.