Closed-Loop dust collection

Hi All,

I have been pondering / conceptualizing a dust collection system that operates as more of a closed loop. In short, the same air gets circulated and “cleaned.”

My theory is that rather than let the vacuumed air escape after being cleaned, it would circulate back onto the work and blow/loosen the dust into the vacuum air stream.

I’m no engineer, so I don’t know the physics of this, but just following my gut in thinking that I can achieve more airflow, move more dust away from the work, and do it quieter.

Because of the stirring up of the dust, This would probably work better in an enclosure.

Just curious if anyone else has experience and/or thoughts on this concept?

Of course the air will heat up till it is at the same temp as the motor that it is supposed to be cooling. Then bad things happen.

In order to do what you want.
You will need to have a water system for cooling. (can be other but water system would be cheapest)
You will have to plan out a recirculating water cooling system that will be used to cool down the air. (As an example… Look at computer cooling and then you will have to scale that up a bit. Most use a pump and a fluid with a radiator.)
Once you have that you will need some way of taking the tiny particles out of the air. This we all use filters for.
You will still need to clean the filters. You can use a slot loading filter system where you have a slot for it and you just swap the old one out for a new one.
The parts and setup is not going to be cheap.

There are ways to cool down the air without water.
If you use something similar to a refrigerator for cooling and have the air pass through the cooling part.
You can use peltier junction devices. They are probably the easiest to do. Just make sure you get the driver for them as building a power supply for them is problematic if your not into electronics.
These get hot on one side and cold on the other. The hot side is put on a heat sink and a fan us used to dissipate the heat. The cold side can then be placed on a duct that you can use to cool the air.

With this device you must not exceed the Voltage 12v and the current 4.5A. It will fail if you do.
You can run it at lower current and voltages. You will just need a good power supply

I have seen some dust shoe designs where they use the downdraft from the router to help direct the chips to the suction intake port. They had some internal ducting but I don’t think it is needed
The router has a fan motor in it for cooling and that blast also clears the chips away from the bit. So you just make sure your dust shoe allows the air blowing out of the bottom of the router to blow into the shoe area to give you that extra airflow boost.

I have not seen anyone try a closed loop approach probably because it is not needed in a typical workshop environment. Any theoretical gains on air movement efficiency are offset by having to mess with more complex filters and return ducting. It is easier to just go with a larger ducting and a more powerful motor, using brute force to get the airflow you need.

Awesome feedback, love this forum!

Heat was definitely something I had not considered.

Robert, short answer is “shopvac.” It is not quieter than my machine, nor does it get all the dust. I know there are solutions mentioned on the forums for both of those issues (better dust shoes, putting the vac in a box), or in your case a proper dust collector.

Fortunately/unfortunately for me my mind doesn’t like solutions that have already been thought of.

Yeah the shop vac is loud, worse they are not made to run for several hours at a time.

FYI; I recommend getting dust deputy to use with your shop vac, It will catch even the finest dust that would normal blow right through your shop vac.

I upgraded to a harbor freight dust collector. It is quieter, but I need upgrade to larger pipes and hoses to get the airflow I need. Right now, using the old shop vac hoses it isn’t very good.

The 4 inch hoses make a really big difference on the HF dust collector.


I am using the HF dust collector as well, with 4 inch hoses and air flow setup properly, this thing will move some air…and remove the chips better then anything I have had in the past.

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