Supercharging a natural gas BG14 burner

[BeardedBrews]

I just found this thread and its very interesting. I don't see the videos of the burners in action can you repost them?

Thanks

https://youtu.be/W55b4BcCPM4

You can see right after he lights it that the BG-14 is putting out way too many BTUs. The excess flame height is the first indicator, and the flame color is a bit too yellow.

 

[Twins_Dad]

^^^^ In Soviet Russia, the BG-14 lights you!

 

[JonW]

Not sure where the video went! Here it is again.

http://youtu.be/DCRbu0H_UwM


edit: anyone know why the Youtube video appears as a link and not embedded?

 

[day_trippr]

What I do: grab the Youtube URL from an actual player session, then post the link using the URL tags...
[ame]https://www.youtube.com/watch?v=DCRbu0H_UwM&feature=youtu.be[/ame]

Cheers!

 

[BeardedBrews]

Not sure where the video went! Here it is again.

http://youtu.be/DCRbu0H_UwM


edit: anyone know why the Youtube video appears as a link and not embedded?

The forum parses the full "youtube.com" links into an embedded mode I think. You could try switching it.

 

[vince805]

I can't wait to see your new build thread!

I have a single tier propane system with a blichman top controlling the mlt, I would love to get rid of it and switch to a bcs to control both hlt and mlt but I cant figure out how to do it.

 

[JonW]

I can't wait to see your new build thread!

I have a single tier propane system with a blichman top controlling the mlt, I would love to get rid of it and switch to a bcs to control both hlt and mlt but I cant figure out how to do it.

My build is getting close! I re-plumbed a few items yesterday and still need to add the fan speed-controller and a couple other small items.


To control your MLT, you just need a solenoid valve that can switch the gas on and off. Couple that with an electric igniter and the BCS can fire on/off to maintain the temp.

 

[vince805]

My build is getting close! I re-plumbed a few items yesterday and still need to add the fan speed-controller and a couple other small items.


To control your MLT, you just need a solenoid valve that can switch the gas on and off. Couple that with an electric igniter and the BCS can fire on/off to maintain the temp.

That sounds so easy, but I'm not an electronics guy. I can solder and follow instructions (like making the brewpi was simple) but when I read up on the BCS threads and it starts getting into relays and stuff I have no idea how to pick out what is needed.

Thinking about the top, it is basically just a box with a gas solenoid valve and an igniter though and it works great. I'll read up some more and see if I can figure it out with the BCS so I don't have to buy another blichman top.

Thanks for the response and looking forward to seeing your new rig! Maybe I can stop by sometime when I'm in the area, I try to go out there every couple months for the salt water fish stores.

 

[jcav]

Nice video, can't wait to see your finished creation!

John

 

[JonW]

For anyone subscribed here, I've posted pics of my new brew rig that has the air injected burner in use.
https://www.homebrewtalk.com/showthread.php?t=572641

 

[dahlseid]

I also had issues with the wiring of my igniters melting some, so I've ordered some fiberglass wire insulation to ensure the leads don't touch.

I'm drawn to the supercharging solution and this thread because I am having related issues, but here I write on a related topic.

The kettles in the current configuration of my stand are causing heat wash onto the wiring of my ignitors and flame sensors, which are mounted in the wind screens (so the wires are on the outside of the wind screens). However, due to the heat wash, they have melted and even caught flame. I'm wondering if you can share what kind of insulation you have used and how effective it has been?

Thannks!

 

[day_trippr]

It'd be helpful to see a picture or two of your stand...

Cheers!

 

[JonW]

My original wire melting issue was due to the wiring being routed inside the front beam of the stand. Since then I have moved the igniters to just below the beam and the wiring being "air cooled" for only about a 3" distance before returning to the beam area. This has been sufficient to keep it from getting super heated. Check out my build thread for pics of the igniter placement.

The fiberglass insulation I used was purchased on Ebay. Search for "Electrical Wire Fiberglass Insulation Sleeving" and you'll see the company I used (or similar results). This has worked well so far. I did order several sizes of the insulation and have it multi-layered over the wiring.

I can tell you that if my igniters were in the rear of my burner shields, that they would still melt due to heat wash, but in the front, they are fine. Knowing what you're looks like might help in determining where the real heat issue is coming from.

 

[dahlseid]

Here is a picture of my stand. The direct spark igniters and flame sensors are mounted 45º off of front center of the wind screens, to one side or the other:



If I could figure out how to post more than one picture, I could show the wires attached to these components, those in best to worst shape, and the photos of the relative position.

 

[dahlseid]

Here is a close up of the igniter and sensor:

 

[dahlseid]

Here is a photo of the challenge:

 

[day_trippr]

Lots of spillage going on, and it isn't obvious how to keep that from happening.
But you could relocate the igniters and their wiring.

I mounted my igniters to the undersize of my bg14s into drilled and tapped holes made directly into the cast iron.
This keeps the wiring under the burner and well below where all the heat is...

Cheers!

 

[dahlseid]

Hey day_trippr -

Any chance you could share a photo of your solution?

Thanks for considering.

 

[day_trippr]

Here's a couple of close-ups of the igniter mounting. I don't have a flame detector but you'd install it the same way.
You could also locate them closer to the center than I did - I don't even remember why I put them that far out on the radius.





The cast iron is very easy to work - indeed, tender treatment during threading is a good idea as it's not as resistant to sloppy technique as say steel or aluminum, and a coarse thread type is advised - but the result is solid. I suppose if you bodged the first shot you could goop in some JB Weld and try again

I should add that my stand has a lot more "breathing room" around the burners as I simply mounted entire Blichmann floor burners in a stand dimensioned to fit them, and those beasts have lots of room for exhaust flow.



So my thermal issues wrt wiring are likely no where near as acute.


Still, routing the wires in the coolest zone is likely your best bet, and that's under the burners...

Cheers!

 

[dahlseid]

Thanks day_trippr. The images are hugely helpful, and that is a mighty fine stand you've got there...

 

[day_trippr]

You're very kind, but in truth it's a mere pretender compared to the plethora of epically fabulous builds you've seen on HBT.



But it gets the job done...

Cheers!

 

[ultravista]

Subscribing

 

[bsent]

So pretty much everyone out there running BG14s on NG must have this same issue.

I have the same issue using BG12's on NG and ran across this thread while researching. Based the results here and my own experiments/research, it does seem likely that many people running burners on NG could probably get more BTU's by pushing more air through the system.

My hunch is that the banjo burner venturi is designed to pull in air based on the pressure and volume of gas coming from the propane regulator (which steps down from high pressure in the tank and is usually adjustable from 0-5psi or 0-10psi). Natural gas sources tend to be much lower pressure(7" WC ~= 0.25psi, 11" WC ~= 0.4psi), so I'm speculating that the blower has two positive effects:

1) Increasing the volume of air in the air/gas mixture
2) Increasing the overall pressure of the air/gas mixture as it enters the burner

Here's what I've learned so far:

1) As shown by the OP, I was able to prove out the concept using an inflator pump I had at home (this was way too strong -- but with creative use of duct tape and other hacks I was able to reduce/direct the airflow to avoid blowing out the flame and prove that this significantly improved my heating time).

2) Using a manometer that I purchased off Amazon, I can see that I'm getting between 6.75 and 7" WC pressure at the orafice. Since my city NG supply runs at 7" WC nominal this seems acceptable/appropriate.

3) Comparing to my use on propane, I can see that the BG12's were running rich (too much yellow) and "low pressure" on NG (flames don't extend as high from the burner), regardless of how high I turn up the gas.

4) At a smaller orafice size, I was able to create a small but efficient flame (all blue). However, with this small flame I could see that the pressure and observed heating power was very low compared to the same burner on propane (very low height, 7G from 64 to 120 took ~30 minutes with NG).

5) By increasing the orafice size, I could get a taller and larger flame but it appeared rich (yellow) and "out of control" (flapping all over the place, extending around the base of the kettle and up the sides if enough gas is added). Note: This is the point where I ordered a carbon monoxide detector from Amazon as well

6) With a slightly larger orafice and increasing both the pressure and the volume of air entering the venturi, I was able to get a nice "clean" blue flame extending a few inches from the burner and significantly improved heating (7G from 64 to 120 in ~10 minutes).

At this point I just need to get this airflow a little bit more adjustable and ducted in a way that's more permanent to my stand. I think I'm going to buy one of the 20cfm squirrel cage blowers that the OP mentioned:

http://www.kr4.us/blower-squirrel-cage-12v.html?gclid=CIei2tblydECFUyAaQodmZ4AkA

Curious if the OP or anyone else has any other tips about this specific blower, what you used for a power source (would be nice to be able to vary the speed), and how you connected the blower to your ducting, etc.

Sorry for the long post -- just wanted to document my experience since I really couldn't find a lot of good info about others experiencing this problem or what they had found.

 

[JonW]

At this point I just need to get this airflow a little bit more adjustable and ducted in a way that's more permanent to my stand. I think I'm going to buy one of the 20cfm squirrel cage blowers that the OP mentioned:

http://www.kr4.us/blower-squirrel-cage-12v.html?gclid=CIei2tblydECFUyAaQodmZ4AkA

Curious if the OP or anyone else has any other tips about this specific blower, what you used for a power source (would be nice to be able to vary the speed), and how you connected the blower to your ducting, etc.

Sorry for the long post -- just wanted to document my experience since I really couldn't find a lot of good info about others experiencing this problem or what they had found.

Yes, I use the same blower you linked. I've since added a second one for my HLT tank. They work pretty good. I tried using a variable speed controller, but the fan didn't respond well with it. I use a strip of duct tape about 3/16" wide that is across the duct tube to lessen the air flow just a little.

I have a stainless tube that is ducted up to my burner so that I can keep the blower motor under my stand with the rest of the wiring stuff. It makes for a really clean installation.

I have thought about drilling out the NG orifice to see if I could get even more gas flow. It would likely no longer work without the blower attached as it would be way too rich, but that's not an issue as I always use the blower.

bsent - please update here with any other tests/findings you come up with.

I personally am very happy with the performance I'm getting now using the air assist. It is nearly equivalent to the wok/jet style burners I previously used, but is silent instead of the incessant load jet engine noise. Also, putting the blowers under the rig also help minimize any sound from them.

 

[bsent]

Yes, I use the same blower you linked. I've since added a second one for my HLT tank.

Awesome. Just ordered two of these myself (one for HLT and one for BK).

They work pretty good. I tried using a variable speed controller, but the fan didn't respond well with it. I use a strip of duct tape about 3/16" wide that is across the duct tube to lessen the air flow just a little.

I had already ordered a variable voltage controller (switch selectable) before I saw this. We'll see how it does. How many amps does your 12v source output?

I have a stainless tube that is ducted up to my burner so that I can keep the blower motor under my stand with the rest of the wiring stuff. It makes for a really clean installation.

Looks pretty. So did you just duct tape the blower output to 1/2" stainless pipe? Can't really tell from that pic what size it is or how it hooks up on the bottom. Unlike yours, my stand is already ugly, so a small shop vac type hose wouldn't appreciably detract from the aesthetic ;-)

I have thought about drilling out the NG orifice to see if I could get even more gas flow. It would likely no longer work without the blower attached as it would be way too rich, but that's not an issue as I always use the blower.

I'll post more later on my orafice size experiments. For my volume/pressure 7/64" seemed to be the right size where at lower needle valve settings I can get a good low flame, and then further opening the valve needs air boost to fully combust. I suspect this is highly dependent on the gas volume and pressure and potentially the burner size, so YMMV.

bsent - please update here with any other tests/findings you come up with.

I will, thanks! And thanks for posting this originally and for responding. As I mentioned, there is very little good info that I could find on this topic, so I think this thread will be useful to others as well. This kind of information sharing is one of the things that makes this hobby so fun!

Thanks,

Blair

 

[JonW]

I had already ordered a variable voltage controller (switch selectable) before I saw this. We'll see how it does. How many amps does your 12v source output?

I have a 3.33A DIN rail mount supply.

Looks pretty. So did you just duct tape the blower output to 1/2" stainless pipe? Can't really tell from that pic what size it is or how it hooks up on the bottom. Unlike yours, my stand is already ugly, so a small shop vac type hose wouldn't appreciably detract from the aesthetic ;-)

It is 1" SS pipe. Yes, the blower is duct taped to the inlet.

I'll post more later on my orafice size experiments. For my volume/pressure 7/64" seemed to be the right size where at lower needle valve settings I can get a good low flame, and then further opening the valve needs air boost to fully combust. I suspect this is highly dependent on the gas volume and pressure and potentially the burner size, so YMMV.

Most NG orifice's are 1/8". That's what I'm running now. I may open it up a bit more to see how it works. Brewers Hardware is real close to me, so if I screw up the valve, I can get another one easily.

I will, thanks! And thanks for posting this originally and for responding. As I mentioned, there is very little good info that I could find on this topic, so I think this thread will be useful to others as well. This kind of information sharing is one of the things that makes this hobby so fun!

Agreed! I post my build threads because I learned so much researching on this forum years ago.

 

[bsent]

Most NG orifice's are 1/8". That's what I'm running now. I may open it up a bit more to see how it works. Brewers Hardware is real close to me, so if I screw up the valve, I can get another one easily.

I was confused by a lot of those conversations at first, then I realized people were talking about two different things -- the orifice size (on the gas valve or input "sleeve") and the gas inlet size (on the burner itself). BG12 uses a 1/8" inlet size, whereas BG14 uses a 1/4" inlet. As for the orifice, the pre-fab ones are usually sold drilled to some arbitrary "average" size that should work for most people. For propane that works fairly well because most propane regulators for this sort of thing adjust to either 0-5psi or 0-10psi. However, on NG you're dealing with much lower gas pressure (0.25 - 0.4 psi). I think that causes three distinct problems that we have to solve:

1) At lower pressure you need a bigger hole (orifice) to allow the same volume of fuel (per second/minute/whatever) into the burner


2) At lower pressure, you also have to find a way to get more air into the venturi and mix it with the fuel to achieve optimal combustion
This is because the venturi design on these burners assumes that the incoming gas pressure will help "pull" the ideal amount of air in to mix with the gas. Natural gas water heaters have regulators, mixers and burners that are better optimized for this purpose. I believe we're trying to force it to work with these common brew burners that are optimized for propane, which is why it requires some extra thought/effort.

3) To generate "max heat" at the appropriate point on your kettle, you need a certain amount of pressure to optimize flame height/intensity
As evidenced by the imprecise language, #3 is more of a hunch on my part. I assume it has to be true, but unlike the other two points I have no backup to support this claim.

Anyway, on to the solutions I tried and what I learned. For #1, you can easily increase the fuel output by "boring out" the orifice. People talk about using drill presses and all kinds of complicated stuff but it's just cutting a damned hole in a piece of brass -- it's not hard and for this purpose it doesn't have to be perfect. Just start small and step it up in small increments (testing in between) until you get what you want. In my case, I ended up intentionally "over drilling" mine so that at lower needle valve settings it would work without the blower (for maintaining a low boil, for example) and as I open up the valve the flame gets sloppy/rich (which i can then resolve by turning on the blower).

As far as needle valves, they're not common on propane orifices (since the regulator has one). I ordered a CVO125 from here:

https://tejassmokers.com/Brass-Fittings-Valves/22#brass7

William's Brewing has a 1/4" one that works with the BG14. It sounds like Brewer's Hardware may have something as well.

Based on some stuff I read on the internet I had them drill mine out to #50, but that turned out to be too small (flame was under control at full throttle, but not nearly enough heat). I kept stepping it up in small increments and ended up at 7/64" for my valve/gas pressure/burner combo (YMMV).

Solving #2 and #3 are where the blowers come in. I think by adding the blowers we are attempting to optimize both the air:gas mix and the pressure. Ideal air to fuel ratio for Natural Gas burners appears to be approximately 10:1 in an "ideal environment". I'm not sure about ideal output pressure for these burners (with the kettle at a specific distance), but I'm fairly certain it's more than what we get with the 0.25psi (and maybe even 0.4psi) provided by most natural gas providers.

Once I get my blowers set up, I plan to play with the fan speed and duct size to try and move the optimal amount of air at the optimal pressure. I'll post a summary of those results in the next week or two.

 

[JonW]

Once I get my blowers set up, I plan to play with the fan speed and duct size to try and move the optimal amount of air at the optimal pressure. I'll post a summary of those results in the next week or two.

bsent - I appreciate your contributions to the discussion here, but you're rehashing what I already know. My point of opening up the orifice (over standard 1/8") is that it will require the forced air at that point to operate properly. Yes, you can use a needle valve to control it for low levels, but once you introduce the air system, you will then need to adjust two flows - air and fuel.

The key thing here is the AFR - air fuel ratio. NG needs to be right around 10:1 for an optimum burn. As you play with the fan speed, duct size, etc. you'll see that your gas flow will have a very limited range where it will work properly at the given (forced) air flow.

If you plan on adjusting your flame during brewing, you'll need to adjust both flows to keep an optimum burn (which will require no forced air for low burner output). I think you'll find that you really don't need a large range of burner outputs for our brewing purposes and picking a fixed air flow and fuel flow will be much easier to work with. This will be especially true if you're going to do any type of automation where your burners are firing on/off to maintain your set temps (as I do).

 

[bsent]

I appreciate your contributions to the discussion here, but you're rehashing what I already know.

Yeah, sorry to have hijacked your thread. Some of that I was trying to rehash both to confirm my understanding and to help document it (since I had so much trouble finding any good info).

I think you'll find that you really don't need a large range of burner outputs for our brewing purposes and picking a fixed air flow and fuel flow will be much easier to work with.

I think you're definitely right on the easier to work with. I do have some concerns about thermal loading though, so I'm trying to come up with an easy enough way to do at least a "low" and "high".

Anyway, I see your point and will definitely take that into account. Thanks again for the help!

 

[dahlseid]

The thread has been quiet for a while, so I would like to ask if some of the last posters have any additional information or data to share? My stand is now complete and has brewed several batches, which I wanted to do before taking on the NG burner BTU output issue. Now I am ready. From what I have read, it seems reliable to plan on using the squirrel cage fans with some pipe to enhance air input to the burner. I already have needle valves on my burners for low pressure NG (from Brewers Hardware), but the thread suggests that I should at least consider that it may be beneficial or necessary to bore out the hole size to gain enough fuel flow. It also suggests that, a variable voltage control for the fan will not be very effective and that I should expect to have to tweak my air flow delivery depending on the tubing size I use and how much fuel I am getting delivered.

So, does anyone have some experience and success to guide me in my efforts? For example, what size (inner diameter) tubing have you found to work best, and with what diameter for fuel delivery and other necessary modifications? Any help will be appreciated!