Now THIS is an exhaust fan !!!

As many of you know I have been working on a controller for the Big Whitfield, and included in that project is an effort to get the stove more efficient and allow more control, both in the fuel feed and combustion fan areas.

Chatting with Don 2222 a while ago and he suggested a much better choice in combustion fan blades.

Just received a new fan from Don and OH BOY, this sucker is not going to disappoint, not even.

Maybe suck the windows out of the stove eh

Here are a couple piccy's

Dirty one one the right is the factory fan from the ADVANTAGE 2 T
The one on the left is the new one.

Old one is 12 blade X 4-3/4 diameter with 1/2" high blades
New one is 11 blade X 4-1/2 diameter with 1-3/16" high blades

That is a lot of difference in air moving ability

This should really help with the ability to control the airflow across a wider range of fuel feeds.

 

Hey snowy you're on to something there, a combustion fan and the LBT combined into one!

 

Yup.

Just open the door and turn the draft fan onto line voltage, then stand back.

For Gawds sake don't leave any doilies on any furniture that's close by Zoooooooop-- gone.

Seriously though, I do believe that this big blade (Also have the 1.75 amp open frame motor) will really work well.

The stove now runs the fan motor at 112 volts which is waaaaay more than factory spec on low feed.

The shells burn great and the clinker takes the better part of a full 24 hour day if not slightly longer to form in the pot.

I was worried that having complete fan speed control would be of little value with the stock blade.

But now with this giant turbine in there, life will get far more interesting.

The plan is to test this entire whizzbang out on the extra ADV2T and work out any "Sucking problems"

 

It's the same booster fan most of the Fahrenheit family have in our furnaces. It will do wonders

 

Here's one used one Don sold me... said it needs 'a little work'... said it would 'save me money'... told me it was the upgraded version of the 'Al Gore 100'....

 

Yeah.

That one looks great

 

We will see for sure just how well it works.

Being able to tweak the speed all the way from 75 volts clear up to nearly line (114) will certainly give a huge amount of latitude to find the SWEET SPOT

As with most companies, they engineer stuff to work within a very small envelope and no manufacture I know of gives the end user any control over this adjustement.

Some stoves have a draft rod, but I will say this, in the years we have had the Whitfield, the positioning of the draft rod has never made much difference.

Now with this super turbine in there churning along this might change.

I have noticed that with the stock blade/motor that on a clean stove and fresh fire the lower 1/4" of the flames will be blue (very good) and opening and or closing the draft rod only seems to lengthen the flames a tiny bit.

I have been involved with airflow in performance engines in years past, and airflow is a very serious science that can at times be confusing.

I have no proof, but would bet that most stove manufacturers don't invest huge sums of $$$$ flow testing their designs.

Looking at the terribly rough and in some cases obstructed passages in the exhaust flow my theory is likely close to spot on.

Sharp jagged corners, rough welds, hard right angle turns and several 180 reversals of flow are not stellar points when it comes to air flow.

Nice curves with minimal obstructions is the key to good flow.

Looking inside the old whit is pretty dismal when thinking about good flow characteristics.

The air comes in through the back of the stove cabinet, up through the fire pot, then past the heat exchanger tubes, then a hard 90 degree turn (one right on that side and one left on the other side)

Then the flow makes another 90 degree turn and heads down into the ash traps on each side.

Once in the ash trap chamber (Outer one) the flow dead ends and has to reverse itself and return up and through a small slot and then take a 180 degree turn and head down into the inner ash traps.

From here it flows down then takes a 90 degree turn (right and left sides flow into the inner exhaust passage)

The inner exhaust passage flows transverse a midship to the left side where the fan housing is mounted.

The flow enters the center of the fan assembly and the centrifugal flow of the fan propels the exhaust out of the exhaust coupler into the vent pipe.

Talk about a convoluted mess.

The Little Whit flows up from the fire pot, through the heat tubes and then through a small port that connects to the fan housings outer chamber, the 90 degrees into the center of the fan and from there out the rear top of the stove.

No reversals and very short traverse of the flow.

Then we read the book and it says to avoid 90 degree bends in the vent pipe.

Whaaaaaaaaaaaaaaaaaaaaaat ???

They already have a metric buttload of switchbacks built in.

Room for improvement for sure.

Definitely not gonna win any awards for ideal air flow.

 

Snowy Rivers , think a set of these should be incorporated in every pellet stove? LOL

 

"Pellet injectors"

 

Retention is key for heat transfer and in our case, small enclosures calls for drastic measures

 

looks familiar, Snowy.
Helga has been like a whole new stove since i gave her the new motor and fan.

 

No doubt

 

I need me one of those!!! I was contemplating going down a dual combustion fan setup on my Fahrenheight, but perhaps that fan will do the trick...