Troubleshooting a Cyclone Chip Clog

Advice on making a cyclone stop clogging when when trying to separate large chips of light material. July 29, 2012

My Torit 36, 20 HP cyclone tends to clog when molding heavy profiles. The opening on the cyclone was 7" diameter. I opened to 9" diameter, but it still clogs at times. Anyone have experience with the correct size opening?

Forum Responses
(Dust Collection and Safety Equipment Forum)
From contributor J:
In general, a cyclone needs to have the right (the higher the better) volume of air moving through it to get good separation, and a tight seal on the discharge to allow material to drop out. What size line do you run from the moulder to the cyclone? What is the cyclone discharging to?

From the original questioner:
14" diameter main line.... great flow... drops into a 6ft x 6ft x 6ft hopper. Usually works great but when molding a heavy profile in a lightweight wood (poplar), occasionally chips clog in the funnel and it's all over.

From Curt Corum, forum technical advisor:
As mentioned, leaks in the hopper may keep chips suspended until unit is turned off. If a bunch fall at once, may clog outlet. Also, I have seen cyclones with an inner spiral wind for this type of problem. Following is a couple of paragraphs from "Practical Design of Exhaust and Blower Systems", written by E.W. Favalora.

In centrifugal separators handling jute, cotton, and other materials of a fibrous nature, it is usually necessary to install a spiral in the entire cone to guide the material to the outlet. Otherwise, it would continue to revolve around the cone continuously until additional material joins it and a ball is formed. This process will continue until its weight becomes too heavy for the pressure to support, after which it will fall into the outlet and very likely cause a choke-up.

All that being said, unfortunately, you would need a new cone. Also, an undersized cone could keep material suspended. But, in the Torit Model 36 Series, they use the same cone for a 20 hp, 25 hp, and 30 hp. This would more likely happen with the 30 hp.

The Torit setup is a pull through arrangement. I guess sometimes a push through is purposely set up so that material enters fan first (chopped up a little) and then sent into cone. If a cyclone tapered body is cut back too much to create a larger outlet, the separation may be affected somewhat.

From contributor G:
I have the exact same dc with the same hp and had the same problem. Couldn't get a straight answer from anyone as to how to fix it. In my case the small airlock was plugging up. Try unplugging that a few times in windy 20 below winter weather and you will be determined to find an answer.

I ended up buying a bigger airlock and cutting the cone back to a 12" or larger opening. I did it a few years back and can't remember the actual opening size.

I remember being really frustrated with not knowing if I was going to screw up the dynamics of the cyclone or not. I figured I had nothing to lose, so I started cutting.

It worked liked a dream and we are still using the system. I have a 6 head moulder, a 30" rough planer and 36" planer/sander hooked to the system. With only 20 hp we can only run one of these at a time while the others are blast gated shut. Never plugged it yet.

From contributor B:
I have a similar setup (15 hp cyclone and 5 head molder) and had the same thing happen several times. Filled the 55 gallon drums all the way up to the top of the 10' tall filter bags before anyone noticed. Total pain! I finally put a 2 hp blower under the rotary airlock with a little 6" duct and now the chips get sucked out of the airlock and blown right into my dumpster. I had to make a plywood manifold that fits under my dumpster lid to accommodate the duct from blower and keep the chips from blowing out. Overall, it works well and we don't have to empty any containers.