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snwcmpr
03/18/2019 8:15 AM
1 lb roasted lasts a week. I can taste the flavor increase to peak, then drop after. Still very good, but interesting to follow the wave of flavor rise and fall.

snwcmpr
03/11/2019 4:10 PM
Roasted Panama Gesha Esmeralda yesterday. Yummy.

Beebee74
03/11/2019 3:10 PM
I seem to have lost any roasting touch I thought I had. Very frustrated to be wasting time and money. I’m hoping someone can provide some insight on roasting at high altitude. I’m at 4400ft. Thank

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03/07/2019 8:50 AM
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Proportional Solenoid Valve for Propane
allenb
Over the last few months I've been experimenting with and am now utilizing a proportional solenoid valve for control of a propane gas burner in a 1 lb drum roaster that I recently converted from Electric to gas. The valve is nearly identical to the Clippard valve Tamarian is using in his fluidbed build here:

http://forum.home...ad_id=3453

My original intent was to utilize a simple on/off solenoid valve to allow cycling between two adjustable needle valves to create a two-state (low and high pressure) output to a burner. Control was going to be my TC4C outputting a 2 or 4 second time base proportional duty cycle to an SSR which would feed the solenoid. One of the problems I discovered is most inexpensive solenoid valves have a rather limited life expectancy in number of cycles and many of them don't like to be cycled as often as every 2 seconds due to overheating potential.

After a lot of searching for modulating valves which seemed to start in the $200.00 range I ran across the proportional solenoid valve listed in the Kelly Pneumatics website and was shocked to find they were much less (between $70.00 and $100.00) depending on size. I also learned they didn't require an expensive, complex valve driver to operate them which would have cost an additional $150 or more.

I spoke to John Kelly who is one of the principals of Kelly Pneumatics http://www.kpiweb...s-MPV.html and was given a run down on a valve that would handle high pressure propane and control in the flow range I needed for my 8000 btu pipe burner in my newly converted to gas drum roaster (see the “Easydrum” roaster in the drum roaster forum). I purchased the mini proportional valve with an orifice size selected by John for working in the pressure and flow range needed for my burner and received it a few days later.

My next step was to figure out how I wanted to control the valve. It strokes from closed to full open by sending it 0 to 10 vdc with a corresponding current of 0 to 180 milliamps which is not possible to power from a TC4 without taxing it's on-board power supply so the next step was to come up with an interface “driver” board that could be placed between the TC4C's output and the valve. Kelly Pneumatics and Clippard sell a driver board that will accept the TC4's 5 volt output but didn't want to spend more than a few dollars on a driver board and decided to build my own. After many conversations with Stan (rustic_roaster) on what kind of driver board design would be best for my application we settled on a two-state driver which sends the valve two different voltages, a lower voltage while the TC4C's output is in the off-portion of it's duty cycle and a higher voltage while in the on-portion of the output cycle (both of these are adjustable via front panel accessible variable resistors). Stan was nice enough to do a complete design and PSpice testing of the circuit prior to my construction of it. This of course allows my burner to cycle in a proportional manner between low and high fire similar to how you would cycle your electric heating element on and off with a TC4 or typical PID controller and solid state relay with the only difference being your element is switching fully on and fully off versus fully on and partially on. I've been able to test the setup on several roasts and with a 2 second time base the burner smoothly graduates it's output back and forth every two seconds without any erratic behavior.

Stan is currently working on a circuit schematic and PCB silkscreen of the driver board which we'll post as soon as he's got it ready to go. Cost for the circuit components was less than $20.00 plus the cost of a pcb from memory.

While I haven't run a gas fired fluidbed roaster using this arrangement, I have no doubt that with a 1 second time base you would see very little temperature swing on your ET thermometer during the high/low firing rates during the TC4's on-off cycling due to a naturally occurring hysteresis from the delay in the change of pressure causing a more sinusoidal change in output versus a quick change from one pressure to the other.

Here's a photo of the Kelly valve
allenb attached the following image:
mpv-lg2.jpg

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
tamarian
Way to go! It's very exciting to finally get a working, safe solution for electronic gas control like the big roasters, on a home budget and not too steep learning curve.
Wa'il. 1 Kg PID'ed gas-fired fluid bed roaster, GS/3MPS, K10F
 
http://english.varietalcafe.com
allenb
Hi Tamarian,

Yes, very exciting indeed! In the near future we'll post a driver circuit or two that can be used for interfacing between a PID controller (like your Fuji) outputting a 0-10 vdc control output and the proportional solenoid.

I'm interested to see how your adventure is shaping up with your proportional solenoid. (no pressure here) Grin

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
tamarian
allenb wrote:
I'm interested to see how your adventure is shaping up with your proportional solenoid. (no pressure here) Grin


Absolutely. I got sidetracked with the safety aspect and had to address it, since you can't access the heating chamber easily on a fluid bed compared to a drum (in case your flame goes out), Now I just need to integrate the arduino safety stuff into the control panel, then drill the ignitor in the heating chamber and add a glass window so the flame sensor can monitor the flame through it. The proportional valve worked fine outside the roaster, and responded well to the PID signal. Just need to cut a few holes into the steel pipe to get the roaster assembled, then tune the whole thing with some old green beans.
Wa'il. 1 Kg PID'ed gas-fired fluid bed roaster, GS/3MPS, K10F
 
http://english.varietalcafe.com
rustic_roaster
This is the circuit Allen mentioned, this circuit was designed specifically for the 10V proportional valve, it might work for the the 5V and 20V valves, but would most likely require a heatsink be added to the Voltage Regulator.

All parts should be easy to source, the attached file has the digikey parts number, but other distributors could be used.

As I said the design was intended to be easy for someone to solder together on a small proto PCB, but I decided to do a little PCB using eagle cad. I found a place called OSHpark that offers low cost PCB fab services. They bundle multiple peoples design onto a larger PCB then separate them to keep costs low. The cost for 3 little PCBs was about $10. The one down side to the service is it takes about 3 weeks to get the boards. Once I get the boards back and verify they work I will post the PCB in the OSHpark share area so anyone can order PCBs if they dont want to create a fly wire board.
rustic_roaster attached the following file:
2sd.zip [16.11kB / 423 Downloads]
 
tamarian
Way to go Stan. This is way over my beginner level electronics. I just started playing with Arduino on breadboard with jumper wires. But with the well documented part list and PDF diagram of those labeled parts, it looks doable/straightforward forward to construct.
Wa'il. 1 Kg PID'ed gas-fired fluid bed roaster, GS/3MPS, K10F
 
http://english.varietalcafe.com
rustic_roaster
tamarian wrote:

Way to go Stan. This is way over my beginner level electronics. I just started playing with Arduino on breadboard with jumper wires. But with the well documented part list and PDF diagram of those labeled parts, it looks doable/straightforward forward to construct.


This circuit should not be bad to build or troubleshoot even for a beginner. It is basically a 3 terminal regulator with an opto relay that switches between two output voltage states as your TC4 or PID controller pulses on and off.


This is a pointer to the PCB I created. I made the project public so anyone can order PCBs.

http://www.oshpar...s/3cSSkv1o

At just over $10 for 3, the cost is more than a bare prototype board, but not having to solder the fly wires may be worth a couple bucks.

Parts from Digikey were about $13/unit plus shipping.

This is a picture of the bare PCB and a built unit.
rustic_roaster attached the following image:
img_6190_sm.jpg

Edited by allenb on 09/15/2013 4:12 PM
 
sversimo
This is just what im looking for!

I need to control a gas heat source, with a FUJI PID.

The power output would be around 3000W max.

Im a mechanical engineer, so the electrical part is beyond my understanding.

Im happy to pay someone to make this work for me!

Sverre.
 
allenb
I've been wanting to post a couple of additional driver board circuits for a while but keep getting side tracked. These are designs by valve companies and should be capable of controlling a valve with minimal tweaking. I'm sure that with minor changes these could be used for either a two-state or fully proportional mode of control. I'm not sure but I think one of them has pots for setting min and max flow.

If anyone builds one and controls a burner with it, please post your results for others to see.

Both companies have given their approval for me to post on our site.
allenb attached the following file:
propdrivercirc.zip [117.92kB / 259 Downloads]

Edited by allenb on 02/27/2015 5:52 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
klix
Hi allenb,

I just downloaded the zip file to have a look at the driver circuits. The one from Clippard is viewable however the .odt file from Parker appears to be missing the content (image). Can you please have a look and repost if necessary.

Thanks for taking the time to research into this!
 
allenb
Sorry about that! I forgot to make it a pdf. Try it again and should open for you. limb

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
In regards to the Parker driver board in the zip file, it looks like it would be an interesting one to try out as it's very simple. For modulating a valve one could place an RC filter between Arduino pwm output and input to the opamp. I've been told that a 10K resistor and .1 mfd cap would do the trick for creating a pseudo variable dc out of the pwm from the Arduino.

For a good discussion on various issues with using the Arduino's pwm from different output pins in addition to using aArtisanQ_PID versus aArtisan see this thread:

http://forum.home...ad_id=4266

Things might have changed since this thread in regards to the Artisan pwm options so be sure to research the latest versions before settling on a design to try out.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb
I looked over the Parker driver chart showing R1 and R2 values for the various valve operating voltages to see what would be the likely pair for your 24 volt valve and noticed the resistance values don't really make any logical sense to me. I would just use the values shown for the 22 volt unit and should be close enough for a 24 volt valve.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
BobbyM15
Does the Kelly valve use an orifice like the Clippard does, if so, why? Why isn't it a straight through valve?
Coffee is a language in itself.

Jackie Chan
 
allenb
Their use of the word "orifice" with the proportional solenoids is somewhat misleading. If you look at a standard precision needle valve there is a seat with a given diameter that the tapered needle seats against when closed and when fully open it allows X cubic volume of gas per minute depending on pressure at the inlet and down stream pressure plus the Cv value of the valve. The Cv value is based on the diameter of the opening of the seat.

Now lets switch to the Kelly proportional solenoid. What they're calling the orifice is simply the opening that a small disc seats against when the armature pushes it into contact with it. As the armature retracts the disc off of the seat/orifice (only moves a few thousandths of an inch) it allows flow to occur depending on how far the armature travels. By choosing the orifice size you're getting the right Cv value to ensure you match the valve with the flow needed by your burner. By choosing the correct orifice diameter you are ensuring that you have a wide enough throttling range so your valve doesn't go wide open after only changing a couple of volts from your control output.

So, the Kelly and Clippard both use the same design with you needing to select the orifice size for a given set of inlet/outlet pressures and Cv value just as you would need to do when selecting a precision needle valve or proportional motorized control valve.

By the way, for what it's worth, the Kelly folks invented the technology used in this type of valve. If you end up using one, Kelly will work with you to ensure you match the valve with the burner gas flow needs.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
BobbyM15
allenb wrote:

Their use of the word "orifice" with the proportional solenoids is somewhat misleading. If you look at a standard precision needle valve there is a seat with a given diameter that the tapered needle seats against when closed and when fully open it allows X cubic volume of gas per minute depending on pressure at the inlet and down stream pressure plus the Cv value of the valve. The Cv value is based on the diameter of the opening of the seat.

Now lets switch to the Kelly proportional solenoid. What they're calling the orifice is simply the opening that a small disc seats against when the armature pushes it into contact with it. As the armature retracts the disc off of the seat/orifice (only moves a few thousandths of an inch) it allows flow to occur depending on how far the armature travels. By choosing the orifice size you're getting the right Cv value to ensure you match the valve with the flow needed by your burner. By choosing the correct orifice diameter you are ensuring that you have a wide enough throttling range so your valve doesn't go wide open after only changing a couple of volts from your control output.

So, the Kelly and Clippard both use the same design with you needing to select the orifice size for a given set of inlet/outlet pressures and Cv value just as you would need to do when selecting a precision needle valve or proportional motorized control valve.

By the way, for what it's worth, the Kelly folks invented the technology used in this type of valve. If you end up using one, Kelly will work with you to ensure you match the valve with the burner gas flow needs.

Allen



Thanks Allen! Great Info!
Coffee is a language in itself.

Jackie Chan
 
allenb
Found another manufacturer of proportional solenoid valves that makes the same style valve as Kelly and Clippard and priced similarly:

http://www.humphr...oportional

These can be purchased at LH Express in quantity of 1 for $79.48 plus shipping:

https://store.liv...

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
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