Problem with Thien baffle setup on HF DC

[atgcpaul]

I have a HF DC which I added a Thien baffle to a couple of years ago. I was about to use it the other day and there was very little suction--even at the inlet--so I know there was no clog in the line.

Today I decided to take the Wynn canister off and to say it was caked in dust wouldn't do it justice. There was easily 1-2 gallons worth of fine dust trapped between the pleats. I spent nearly an hour beating the filter and sucking out the dust.

This got me thinking that the way the HF DC is retrofitted with the Thien baffle isn't optimal. The baffle sits below the inlet while there's a huge hole (albeit with a downward facing cone) above it. Why wouldn't the dust want to migrate upwards?

Shouldn't there be another baffle in the opening to limit how much dust can rise up into the filter?

[dbhost]

If configured correctly, the baffle is supposed to block the flow of the dust laden air stream until it has an opportunity to drop most of the dust before it exits...

A couple of things can cause severe problems with a Thien, a regular cyclone, the Jet cone thing a ma jig etc...

First and foremost, excessive restriction to the airflow will cause the dust laden air to bypass the lower bag and baffle and head straight to the filter.

Secondly, NO separator, or cyclone removes ALL of the dust from the air before it hits the filter, if it did, you wouldn't need a filter. Even with a separator you need to periodically clean your filter. My rig is an HF DC with a 55 gallon Thien separator, and Wynn 35A, I have filled / emptied the separator no less than 6 times since the build about 4 and a half years ago... I once every few months simply blow down the outside pleats of the filter, and I have so far accumulated less than a gallon of material in the lower bag. I recently (within the last month) had the opportunity to view the inside of the pleated canister. It was anything but caked. I am actually a bit concerned the separator might be doing its job too well.

My shop vac separator however clogs up QUICKLY when I connect it to my sanders. They don't allow enough air flow. I am looking to add some sort of means to get makeup air into the system to fix this problem...

Specific to the thien design is you MUST make sure your baffle orientation is correct or the dust WILL bypass it. The solid part should start right at where the air intake is, and rotate around 120 degrees....

Okay, I just spent what I know about this subject. Anything deeper and you will probably want to check with Phil...

[LCHIEN]

Daves observation that a filter has to stop some dust or else you wouldn't need the filter is right on.
We don't know how much you use your saw and what machine's stream are you capturing from so we don't know the total quantity or the makeup of the stream - fines or coarse. If you've been using it for two years and never cleaned your filter then, this is all believable.

Try cleaning it more often.

One way to see how optimal your airflow is is to look at the current drawn by the running HF 2HP DC
With open inlet and no filter it will probably run 15-16 amps. as you add restriction the current will go down and the unit will get louder (counterintuitive, perhaps) but moving air = work done so moving less air will make it take less current.
I have wondered if monitoring the current of your DC is a good way to measure the performance and tell you when to service it and perhaps how to tune it. Loss of airflow due to plumbing restriction and or clogged filter will give lower current. Adding a preseperator must surely put a hit on the unit but I don't know how much - this would give a way of measuring it.

[atgcpaul]

Specific to the thien design is you MUST make sure your baffle orientation is correct or the dust WILL bypass it. The solid part should start right at where the air intake is, and rotate around 120 degrees....

I'm going to check this first since the upper and lower parts are off now.

Maybe I was too optimistic about what to expect. I do beat on the pleats at least every time I change the drum. I guess I'll incorporate a session with the compressed air, too.

I do have my sites set on reconfiguring the setup. I have a separator lid but including that takes up so much space I don't use it. The side flipped orientation is what I had in mind.

[atgcpaul]

I'm going to check this first since the upper and lower parts are off now.

Maybe I was too optimistic about what to expect. I do beat on the pleats at least every time I change the drum. I guess I'll incorporate a session with the compressed air, too.

I do have my sites set on reconfiguring the setup. I have a separator lid but including that takes up so much space I don't use it. The side flipped orientation is what I had in mind.

Back in business. The solid part of my baffle started approx 2" behind the trailing edge of the inlet hole. I rotated it about 2" forward. Anyway, we'll see how long this performance lasts.