Add a "Smokin-It" Cold Smoke Generator to Timberline 850

[RemE]

Drills and taps just arrived, air pump and tubing tomorrow, right angle barbs Thu&Fri. So next Saturday most likely will be the test fire.

 

[RemE]

Bella "Turbo Quatro" Mod is complete!

Recap, these Cold smoke generators are designed to blow smoke into a larger box, to cold smoke fish, cheese, salt etc. Adding these units to a pellet grill works great, until you fire up the grill and try to get more smoke. Maybe not all, but my sealed Timberline has some positive pressure in the pit when running. This causes the grill to blow into the smoke generator, defeating its simple air jet venturi system and yielding no extra smoke, and a mess inside of the generator

SO, the plan is to seal the top, add air supply to the top and side vents along with the stock air input port (Hence the Quatro name). This will prevent back flow from the positive pressure, of a running grill, into the smoke generator.

Here's the construction details.

Side Holes, Due to the diameter of the existing holes, I used 1/4" NPT to 3/16" barb elbows. I bought a tap /w drill bit and tapped both sides. BTW, the 16ga stainless steel Bella body is hard stuff to drill and tap for non metal workers like me!

Top Cover, I removed the knob, drilled and tapped the hole for a 1/8" NPT to 3/16" barb elbow. I added 1/8" ceramic wool insulation into the top cap, then added a square of 26ga stainless over the insulation. I used high temp silicone to seal the cover when in place. Hopefully this will reduce any condensation in the top as there will be air flow now.

Air Control, I used a 4 port air manifold and the existing Bella pump. This manifold will allow adjusting the flow rate to any of the ports if needed. The manifold came with suction cup mounting clips, I used a dab of clear silicone glue in them and stuck the manifold under the side shelf to hide all of the spaghetti.

Smoke Output Tube Extension; Thanks to Slimpicker for the idea, added a stainless tube extension to direct the smoke release to a place where the fire pot is blowing away from the smoke outlet.

Results?
Test1 - I loaded up the Bella with pellets and applied a torch to the side port, once running, I screwed the elbow fitting into the port and attached the tubing. So Far so good. Smoke was flowing nicely into the grill, next was to let it run for an hour, then check.

Test2 - If all good, fire up the grill and hopefully not see any loss of smoke from the Bella.

Unfortunately, Test1 failed due to cheap air tubing, turns out the stock tubing as well as the "Silicone" brand I bought melted promptly on the side port after firing up. I have new Hi-Temp rated (500F) silicone tubing coming on Tuesday.

To be continued!

 

[Slimpicker]

Now I need to sit here tomorrow and study this

I have new Hi-Temp rated (500F) silicone tubing coming on Tuesday.

I noticed my Stock tube started to deteriorate on the end also....

 

[RemE]

Now I need to sit here tomorrow and study this



I noticed my Stock tube started to deteriorate on the end also....

Yes, these hose barbs get hot in use. This tubing is rated to 500F. The stock tubing is maybe 200F at best, mine was distorted as well. The new side vent elbows will probably be 300-400F range I'd guess.

SUPCO SSRT3165 Silicone Tubing, 5 Feet Length, Red, 3/16" Inside Diameter, 5/16" Outside Diameter, 20 psi Working Pressure, -100 Degree F to 500 Degree F https://www.amazon.com/dp/B071X9FDNL/ref=cm_sw_r_em_api_glc_fabc_MOeZFbXDK0JPG

 

[Smudge]

Hey Guys,
Looks good RemE! Can’t wait for the next round. I was sitting here looking at this post and thinking about the Bella. Has any tried just straight wood chips yet? If it condensed again with chips, would it just be “soaking” them and smoldering?

 

[RemE]

Hey Guys,
Looks good RemE! Can’t wait for the next round. I was sitting here looking at this post and thinking about the Bella. Has any tried just straight wood chips yet? If it condensed again with chips, would it just be “soaking” them and smoldering?

Chips would not be affected by condensation much at all, and certainly wouldn't swell and crumble like pellets when wet.

In normal use as a cold smoke generator, the Bella's single air jet venturi tube should draw outside air into the unit thru all openings, side holes, top etc. and then exit thru the smoke tube into the smoking box, or grill in our case.

I think we are mainly seeing condensation due to back pressure from a running grill, stalling the Bella's air flow and causing condensation mayhem. The Bella and Smoke Daddy only have a very low flow aquarium air pump to create air flow, they can't match these fan powered pellet grills in operation, without modification to stop back flow.

 

[Smudge]

What I’m worried about is I had condensation when my grill was not running at all. I still think we might be fighting 2 things....first being back pressure and second hot stainless steel inside and cold outside. Now, I wonder if the condensation problem is this bad during the summer? Like you and Slimpicker, I really want to figure out a way to make this work. Did you happen to call Smokn-it to see if they had any advice? Enjoy this post and all the “outside” the box thinking. Thanks guys!

 

[RemE]

What I’m worried about is I had condensation when my grill was not running at all. I still think we might be fighting 2 things....first being back pressure and second hot stainless steel inside and cold outside. Now, I wonder if the condensation problem is this bad during the summer? Like you and Slimpicker, I really want to figure out a way to make this work. Did you happen to call Smokn-it to see if they had any advice? Enjoy this post and all the “outside” the box thinking. Thanks guys!

I was afraid of that, well then yes, it was probably low pump flow setting coupled with cold outside air. The airflow was low enough to not draw the steam away from the pellets and out the smoke tube as they heated.

Hopefully my mods will allow us to control the airflow better and hold off condensation with the 4 port air manifold. For example we could close the valves for the side vents and direct flow just to the top and air jet ports.

I will contact the Bella folks for sure next week seeing as this occurs with or without the grill running. last time I spoke with them, when I ordered the unit, was that they had just gotten a new batch and the new units are now made from 16ga stainless where the previous models were thinner 18ga material. Who knows, maybe this caused an unintended change in performance in cold weather.

Fun stuff!

One may ask, why not just throw in the towel and use a smoke tube tossed into the grill. I'm not there yet, still chasing the dream for true cold smoke for up to 9 hours.

 

[Smudge]

I agree with chasing the dream!!!! How can we help? Would it make sense to have your 4 port design as well as several open holes to help with the air flow (force the moister out)?
I have a friend that has his own tin shop and has been a HVAC technician for 40 years, I’ll pick his brain tomorrow as well. It will be interesting to hear what Bella folks say.

 

[RemE]

I agree with chasing the dream!!!! How can we help? Would it make sense to have your 4 port design as well as several open holes to help with the air flow (force the moister out)?
I have a friend that has his own tin shop and has been a HVAC technician for 40 years, I’ll pick his brain tomorrow as well. It will be interesting to hear what Bella folks say.

No, the idea with my mods is to seal the Bella and pump all air needed for combustion thru the 4 ports and out the smoke tube. This should make it impervious to the grill when in use and hopefully control the condensation as well.

If only using the Bella with the grill off, leaving the top off might let any steam just escape. But, I'm hoping that my mod will control that issue.

 

[RemE]

I agree with chasing the dream!!!! How can we help? Would it make sense to have your 4 port design as well as several open holes to help with the air flow (force the moister out)?
I have a friend that has his own tin shop and has been a HVAC technician for 40 years, I’ll pick his brain tomorrow as well. It will be interesting to hear what Bella folks say.

OK, just spoke with the Bella folks. They originally marketed the unit burning pellets only, mainly because they drop down well and burn without any voids developing. Pellet quality affects how much they are affected by moisture etc. but they now recommend a 50/50 mix of pellets and chips for better burn and smoke quality. I asked about higher ratio of chips, he said that might be ok but the key is to maintain good fuel feed and no voids which cause flameouts.

I told them about my experience with the running grill and he mentioned that some others put Bellas on RecTec grills with similar blow back issues. Some created baffles and the extension tube that Slimpicker keyed on to shield the Bella from direct fan blast can help.

Also, he mentioned that a bigger air pump might be able to overcome the back pressure as well. I could see adjusting the air flow until no smoke blew back out of the Bella's vents. But how big would be the question.

So I'll be getting some wood chips to mix for my next test. He suggested "Western" brand chips from big box stores etc. Hickory or Mesquite are his favs. about $2 for a 1lb bag.

 

[Slimpicker]

they sent me a bag of pellets/chips with my Bella... I'm guessing now that was suppose to be a hint as to what I was supposed to be using instead of 100% pellets... (come to think of it now, when I used those in my first 2 smokes I didn't have as big a problem as straight pellets)
I got A LOT of Traeger pellets left that I will never use in my Hopper so I'll start using them up in Bella and if they get ruined each time, WHO CARES... I was gonna sell them of give them away anyway.
I'm a BEAR MOUNTAIN man now.

 

[Slimpicker]

Also, he mentioned that a bigger air pump might be able to overcome the back pressure as well. I could see adjusting the air flow until no smoke blew back out of the Bella's vents. But how big would be the question.

Get the DUAL pump and supply the manifold with 2 intakes
I found my 4 outlet pump that needs the diaphragms replaced... I always have on running outside for my 3 ponds.
I'll bet I still got 2 good pumps in that one.

 

[RemE]

Get the DUAL pump and supply the manifold with 2 intakes
I found my 4 outlet pump that needs the diaphragms replaced... I always have on running outside for my 3 ponds.
I'll bet I still got 2 good pumps in that one.

I don't think a larger pump is needed with my Bella now being pretty much sealed. I did get a 4 port pump with dual diaphragm but returned it, decided that the stock pump with 4 port manifold and adjustable valves would be better and a little cleaner tucked up and away with one tube down to the pump.

 

[RemE]

OK, tested yesterday, success! With the Bella sealed, the stock air pump was enough to push smoke into the running grill.

First I ran the Bella for over an hour with the grill off, works normally with almost no smoke leaking from the unit. Also, there was no condensation inside the pellet lid. I also sealed the bottom cap with some 1/8" ceramic fiber gasket material and a piece of 26ga stainless to cover most of the wool.

Next I fired up the grill at 300F, the Bella continued to operate normally. Nice blue smoke coming from the grill. If I took the Bella lid off, it was clear but smoke would soon begin rising up. This means that the sealed top with air injection is working well to hold off condensation.

I ran the grill for two hours and all was good, the new high temp silicone tubing had no issues with the heat of the Bella.

So, tonight is an overnight brisket test with added hickory smoke. The Bella will be 50/50 chips and pellets.