Thread subject: Homeroasters - Home Roasting Coffee Community :: Another 1.5kg or 3lb drum roaster from scratch
Posted by oldgrumpus on 07/09/2016 4:08 PM
#1
It looks like we're much closer to a final design for the gas chain. The gauge is from this website: http://www.aicons...vAod-y0N6w
How's this look?
Posted by allenb on 07/09/2016 6:12 PM
#2
Looks good to me.
Here's a link to a valve with an appropriate CV for your application at the Generant valve site. Click on the flow coefficient tab and look at the standard stem model. We're shooting for a CV of around .099 or round to .1 at a few turns which will give you around 7 cubic ft/hr maximum flow with an input to the valve of 11" H2O (.4 psi) and a downstream pressure leaving the valve of around 7" H2O (.25 psi). 7 cubic ft/hr equates to around 17,000 btu/hr which is equivalent to 5kw which will give you plenty of heat for a 3-4 lb drum roaster with a little headroom :
You can probably find a good deal on a similar valve on ebay but make sure you find one with a CV/turns value similar to the one in the link to ensure you have good control.
I did a price check for this valve and it would be hard to beat their price! This one is brass with 1/8" female pipe on inlet and outlet:
The "titanium" burner I ordered arrived and although of reasonably nice quality, is not titanium, nor is it stainless. It appears to be mild steel sheet metal because it is strongly magnetic. I guess my expectations were too high
Amongst the photos of the burner is one view of the input end which I didn't think about before ordering because it wasn't clear to me what if anything would be needed. Advice needed. It looks like an orifice and supporting mount will be needed... help!
I'm also trying to select a needle valve. Right now I'm leaning toward a Generant FNV in stainless or one from the Screwed Bonnet product line (also a Generant). The Screwed Bonnet is similar to the FNV series, but uses less rotations to open and close.
Edited by oldgrumpus on 07/12/2016 3:21 PM
Posted by oldgrumpus on 07/12/2016 7:45 PM
#4
"Titanium" burner.
Posted by allenb on 07/12/2016 8:50 PM
#5
Quote
It looks like an orifice and supporting mount will be needed... help!
In a typical burner setup, the orifice will be screwed into a pipe fitting (tee or 90) and the orifice or jet assembly will support the inlet end of the burner (sticking through the hole of the "U" bracket on your burner) and a sheet metal bracket will support the weight of the other end. The bracket should be arranged as to not allow the burner to slide away from the burner jet. I doubt they sell mounting hardware but thin sheet metal should allow you to make one relatively easy.
Looks like the jet is reasonably priced.
Allen
Posted by oldgrumpus on 07/26/2016 8:39 AM
#6
I have nearly all the parts now for the gas system with the exception of the Generant needle valve which is 6 weeks for delivery!
While waiting, I'm pondering how to appropriately size the exhaust system. Any thoughts on that? I could wing-it, but would rather go in confident that it's a good design.
Posted by oldgrumpus on 01/14/2017 8:07 PM
#7
Uploaded a video
Posted by oldgrumpus on 01/14/2017 9:33 PM
#8
Here's a new video showing a test of the drum and vanes.
Posted by oldgrumpus on 01/14/2017 9:44 PM
#9
The back side and motor. No structure yet, just checking out some of the mechanics..
.
Here is a video of my gas setup. I need some help figuring out how to get a bigger flame that has less yellow. I know it needs more air, but how? Is my gas pressure to low? Why is it pulsing?
Posted by allenb on 01/03/2019 6:44 PM
#19
A few questions
Pressure entering the gas valve?
Max allowed gas pressure to your gas valve?
Burner orifice size?
Btu rating of the burner?
Posted by oldgrumpus on 01/04/2019 2:41 PM
#20
Pressure entering the gas valve has not been tested. I will do that, but until then, here are the specifications of the valve:
Specifications:
Manufacturer: White-Rodgers
Model # 36C03-333
Ignition Type: Standing Pilot
Gas Type: Natural or LP Gas (LP Conversion Kit Included)
Stages: 1
Opening Characteristics: Fast
Max BTU/HR @ 1" Pressure Drop: 230,000 (Natural); 372,600 (LP Gas)
Voltage: 24
Hertz: 50/60
Amperage: 0.230
Pressure Regulator Factory Set To (Natural): 3.5" W.C.
Pressure Regulator Adjustment Range (Natural): 2.5"-5.0"
Pressure Regulator Adjustment Range (LP Gas): 7.0"-12.0"
Maximum Pressure: 1/2 PSI (14.0" W.C.)
Inlet Size: 1/2" NPT
Outlet Size: 3/4" NPT
Pressure Tap Size: 1/8" NPT
Pilot Gas Connection: 1/4" Compression Fitting
Ambient Temperature Rating: -40? F to 175? F (-40? C to 79? C)
