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Gas Control advise needed
kwrcst
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Posted on 11/25/2019 8:28 AM
Hi all

So I'm building a Frankenstein Drum roaster on a BBQ grill platform. I have the 3 knobs that are native to the 3 burners on the grill but I want to eliminate them and take it to 1 control.

My thought is, If I turn them all to high and remove/cover the face plate, they will stay in that position and I can put some kind of control valve and gauge in-line before the gas hits those control valves. The issue is I don't know what my options are for Propane. I've googled and all I come up with are propane tank pressure valves that show full/empty.

I would think there would be a screw type valve, like a water faucet, and then I would have a gauge that shows pressure that I would put just past the valve. This would allow me to accurately control the flow.

Any suggestions on what I need or what you all use would be appreciated. I don't want to change out the native burners as they already provide more than enough energy to roast the size batch my drum will hold.

thanks

K
 
baldheadracing
Top  #2 Print Post
Posted on 11/25/2019 4:55 PM
Try googling "needle valve parker propane" (although I don't think that the needle valve on my roaster is a Parker). You will definitely need a gauge.

Here's an example: https://www.home-...45353.html
 
kwrcst
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Posted on 11/25/2019 7:27 PM
Awesome link. So it looks like I need a needle valve and a mono meter for propane. Just curious, what flow rate range do you use?
Big help! Thank you
 
baldheadracing
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Posted on 11/25/2019 9:42 PM
I have a regulator at the tanks that drops the pressure down to 210mmAq to 230mmAq. The burners can idle at about 50mmAq, but I'm running between 120 and max. when roasting (and not soaking). However, I'm not sure how applicable those numbers would be to your situation, as I'm using this small 1kg commercial roaster: https://forum.hom...ad_id=4142
 
pisanoal
Top  #5 Print Post
Posted on 11/26/2019 6:28 AM

Quote

kwrcst wrote:

Awesome link. So it looks like I need a needle valve and a mono meter for propane. Just curious, what flow rate range do you use?
Big help! Thank you


I wrote up an explanation of the needle valve/rotameter combo from Dwyer Instruments with a link to their site. The combo was relatively inexpensive and works great. There is also some example calcs to help you figure out what flow range to get based on your desired BTU range.

If you gi that direction and need help selecting one, let me know.

https://forum.hom...ad_id=6052
 
kwrcst
Top  #6 Print Post
Posted on 01/22/2020 2:36 PM
So I finally figured out what the burner set in my grill is. The specs show it has 3 10,000 BTU burners.

Since I am not familiar with gas flow regulating etc, can someone tell me which dwyer flow meter or parker valve I need for this? I'm just not sure how to figure out the gas flow to reach max BTU
 
kwrcst
Top  #7 Print Post
Posted on 02/13/2020 3:22 PM
So I just found a good deal on a 2" scale dwyer flowmeter 1-10LPM but my question is do I still need a parker valve? I have a propane tank with a regulator on it that I manually turn off and on before I start. Can I hook that directly to the flowmeter or do I need another on/off between the tank and meter?
 
allenb
Top  #8 Print Post
Posted on 02/13/2020 5:11 PM
If the particular Dwyer flow meter you will be buying is the combo with needle valve then you do not need the parker needle valve.

No need for an additional isolation valve if you will be shutting off the tank each roast. The needle valve will stop flow to kill the flame after a roast.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
kwrcst
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Posted on 02/13/2020 5:15 PM
That makes sense. I figured the tank shut off would work but if I want to kill the flame, I?d have to go to the tank each time. I may put an on/off valve before the flow meter just for that. Not sure I actually need a Parker that can be dialed open and closed. Maybe just a gas rated ball valve would work
 
kwrcst
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Posted on 02/24/2020 7:44 PM
Question:

I got the Dwyer flow regulator and it has a 1/8? threaded input/output. Will necking this down from the standard fitting size of a bbq grill propane line change the flow to the burners? I?m basically taking the 5/8? line, taking it into a 1/8? hole and sending it back out a 5/8? line. Will the velocity be the only change or will the amount of gas be reduced and my burners not work?

If it?s the latter, anyone got a good work around for this?
 
jscott14
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Posted on 02/25/2020 10:08 AM
A 1/8" orifice on roughly 10psi propane can supply over 100,000 BTUs, so this shouldn't negatively impact you at all. (I'm making broad assumptions with these figures, since the shape of the "step-down" to 1/8" impacts the coefficient of flow, but still, if your setup is 30,000 BTU, you are absolutely fine to have a 1/8" orifice in the path.
 
kwrcst
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Posted on 02/25/2020 4:40 PM
You rock. I?ve been trying to think of a plan b lol
 
kwrcst
Top  #13 Print Post
Posted on 02/29/2020 7:13 PM
Ok, need a plan B. with the Dwyer in line, I'm not getting enough heat to break 320d. I went from the tank to the burners and bypassed the dwyer and got to 360. Now it is 50d outside and a bit windy so I think that is why I couldn't get it hot enough but I think the 1/8" flow meter is restricting the gas too much.

I had a much larger flame at all 3/8" I guess I need to find some type of control valve that is that size and allows for precision adjustments. Or maybe my burners aren't big enough. I did see on amazon they have some cast iron burners designed for a Wok like you see in the Chinese restaurants. https://www.amazo...B071749XB4

says 100,000 BTU
 
jscott14
Top  #14 Print Post
Posted on 03/02/2020 12:46 PM
Something isn't adding up to me. A single 1/8" orifice shouldn't cause a bottleneck in your system. In fact, over the weekend I converted my drum roaster from propane to natural gas, and I wasn't getting enough BTUs. I looked at my gas jet, and it was 1/16". I drilled that out to 1/8", and the difference was massive. (In fact, it's TOO big... at full throttle, I get 8 flames that shoot up about 6"!!).

PERHAPS the issue is that we're dealing with more than one point of restriction. You still have the factory knobs in place, correct? Perhaps stepping down to 1/8", then passing through THOSE restrictions is where the bottleneck is coming into play. Is it possible to completely bypass the stock knobs?

Is your gas pressure adjustable? Can you try upping the gas pressure a bit to see if that helps the issue?

Regarding the burner above, I have a similar burner on a turkey fryer... unless your drum is quite small, I would think that this type of burner is too small. You'd have one section of your drum with direct heat from the burner, but the rest of it wouldn't be as hot. That's just a hunch.
 
kwrcst
Top  #15 Print Post
Posted on 03/02/2020 12:59 PM
If I were to bypass the stock valves, I would have to build an entire new burner system. the valves are needles that pierce 1 pipe the gas comes in through. I think there is so much more metal involved in this system that when it was a grill, that it is just eating up that heat and I can't put it out fast enough to over come that. I did go straight from the tank to the burner like when it was a stock system as a grill and still couldn't achieve the temps I was able to get as a grill.

I ordered 2 of the 100,000 BTU burners from amazon. I am also going to perforate the base plate a ton more to reduce that heat absorption. These new burners will take a much higher flow than the stock system I have now. I have a parker valve coming this week so I will have some control of flow there as well.

I hear what you are saying about it not being enough but I think inside the closed system I have and by adding 2 of them, I should be able to generate enough. with the 30,000 I was producing this weekend, I got close but just didn't have enough umph to get it there. 200,000 BTU may be inefficient for the system but if I can get the output I want, it will work until I can figure out a better solution.

I will keep you posted

Kelly
 
jscott14
Top  #16 Print Post
Posted on 03/02/2020 3:00 PM

Quote

kwrcst wrote:

I did go straight from the tank to the burner like when it was a stock system as a grill and still couldn't achieve the temps I was able to get as a grill.

Kelly


I think this might be the culprit. You can't go STRAIGHT from the tank to the burner... that would be around 150psi unregulated LP. Which then leads me to suspect that you have the "stock" regulator in place. Is this true? Those non-adjustable regulators are anemic. Often less than 0.5 psi. Add restriction into the equation, and there's your bottleneck. If I were in your shoes, i'd start with getting an adjustable regulator, not a different burner.
 
kwrcst
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Posted on 03/02/2020 4:19 PM
What psi should I get in the regulator
 
jscott14
Top  #18 Print Post
Posted on 03/02/2020 4:33 PM
Just a standard 0-20psi LP regulator should do the trick.
 
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