topbanner.gif
Login
Username

Password




Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
Shoutbox
You must login to post a message.

07/24/2021 2:58 AM
welcome cup Danny

07/21/2021 3:00 AM
Welcome RoastedRight

07/18/2021 3:06 AM
Welcome to darkbrew, carl1961 and vitor !

07/17/2021 4:30 PM
Welcome Skin Destination AND Timberline

07/16/2021 3:10 AM
Welcome to callmejohn and axissolutions !

In Memory Of Ginny
Donations

Latest Donations
JackH - 25.00
snwcmpr - 10.00
Anonymous - 2.00
Anonymous - 5.00
Anonymous - 5.00
Users Online
Guests Online: 15

Members Online: 0

Total Members: 7,257
Newest Member: Danny

View Thread

Who is here? 1 guest(s)
 Print Thread
Needle Valve Question
Mustang967
Okay I apologize if this has been answered before but I haven't been able to find an answer.
I am trying to decide on a needle valve for my propane Fluidbed roaster. http://www.clippa...rt/GNV-3KI This is the one I'm thinking about buying but my question is if the flow will be great enough. it looks like it will flow about 11 scfm @100 psi. Obviously I'm not going to be anywhere close to 100, I have a 0-20 psi propane regulator that is probably kept well under 10psi. I'm currently using a very cheap needle valve from amazon that I barely open and varies wildly with very little adjustment.
So I'm looking between the GNV-3 or the GNV-4.
www.clippard.com/static/images/cache/e2/e271ca188edddb407e36cf251c149429097fdc11-900.jpg
The GNV-3 looks like it has a very gentle slope per turn, but my concern is if it will give me enough flow.
My roaster uses a Bake-A-Round for the roast chamber and a homemade forge burner for my heat source. I don't use near the full capability of the burner so I think it will work but i'd prefer to not waste the money.
Thanks for any help!
allenb
Welcome to HRO Mustang!

Before we can help you in your selection of a needle valve for your application we need to first find out the orifice size in your burner. This is a key piece of information that governs all other calculations. This will allow us to determine the flow in cubic feet/hour at a given input pressure to the burner. With this information and knowing you'll be sending your needle valve a max pressure of 15-20 psi, we can determine the CV value the needle valve will need to have to allow a good turndown ratio.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967
Hi Allen, thanks for the welcome. I greatly appreciate all the information that is on this forum. It helped me immensely during the build of my Roaster.
As for the orifice I bought the micro drill bits from harbor freight and used the smallest one in that pack and it looks like that's .5mm. Thanks again!

Royce
Edited by JackH on 06/19/2016 3:45 AM
allenb
You're welcome, we are glad to help our fellow home roasters.

A burner with a .5 mm orifice will hit around 8500 btu/hr and hit a flow rate of 3.5 cubic feet/hour at a pressure of 3.5 psi propane according to the charts I've got available to me. 8500 btu/hr is the equivalent of 2500 watts which will easily roast 1lb + some headroom.

A needle valve capable of smoothly finessing your burner output will need a CV value of around .005 at anywhere from 1 to 5 turns.

I couldn't find any CV versus turns charts on the Clippard GNV-3 valve. I would call them and have them give you this information. Without it, there's no guarantee of how well this valve will perform. If they can't provide you with this information, ask them to tell you how many cubic feet per hour of propane the valve would flow with a 15 psi input and a 3.5 psi downstream pressure. Give them your burner orifice size as well. Sometimes companies will be reluctant to expend much effort on you if it's known you're looking for a single purchase but it's worth a try.

Here's a CV/turns chart on a valve that fits the bill for your roaster build
allenb attached the following image:
pmv_chart_1.jpg

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967
I emailed Clippard asking them about the details of the two valves and attached is what I received. This was the engineer's best estimate of CV per turn for these needle valves. This was an impressive amount of work done by this guy and I really hope it gives us an idea of which valve to choose. Thanks

Royce
Mustang967 attached the following file:
propane_cv_calculationxlsx.zip [42.94kB / 273 Downloads]
Mustang967
Someone else posted this but it disappeared. I'm attaching an image of the spreadsheet so people don't have to download it.
Mustang967 attached the following image:
propane_cv_calculation.png
allenb
The charts Clippard put together for you show 60 cubic feet/hour with a 15 psi input pressure and 3.5 psi downstream pressure. You'll want a valve that will flow no more than 4 or 5 cubic feet/hour when close to full open.

I would send the person you worked with at Clippard a copy of the Generant PMV valve CV chart and see if he has anything to offer that gets close to those numbers.

http://www.genera.../pmv.shtml

As you can see in the Generant chart, at around 8 turns you're only up to a CV of around .020. The Clippard valve is hitting a CV of 21 at 1 revolution.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967

Quote

allenb wrote:

The charts Clippard put together for you show 60 cubic feet/hour with a 15 psi input pressure and 3.5 psi downstream pressure. You'll want a valve that will flow no more than 4 or 5 cubic feet/hour when close to full open.

I would send the person you worked with at Clippard a copy of the Generant PMV valve CV chart and see if he has anything to offer that gets close to those numbers.

http://www.genera.../pmv.shtml

As you can see in the Generant chart, at around 8 turns you're only up to a CV of around .020. The Clippard valve is hitting a CV of 21 at 1 revolution.

Allen



I responded to the person asking if they sell any needle valves with significantly lower flow and control and I'm waiting for a response.
I was just browsing through their site and I found this one http://www.clippa...art/MNV-2K It has an SCFM of 1 @50PSI and assuming the flow is linear I figured the SCFM would be about .3 @ 15 PSI and using the Generant CV calculator I got a CV of 0.0232 at full output. When I get a response back from the engineer if they don't have a better option I think I'll just try it as its only 10 bucks and I'll post my results here. I couldn't find any prices of the Generant valves but I'm guessing they will be more than $10.
Royce
Mustang967
I just got a reply from the person I have been talking with and he said that the MNV-4K would be a better option.

Quote

"You are correct that the MNV-2K has the lowest max flow rate, but the MNV-4K is going to give you a greater window of adjustability. The -4K flow rate changes less per turn than the -2K. ( For example: 4 turns of the knob will completely open the -2K vs. the -4K that will still be under the 1 scfm at the same number of turns). Keep in mind that both options can reach 0 scfm, so either option will work for your application."


I'm going to order one and see how well it works. Regardless I'm sure it will be better than the cheap amazon one I'm currently using. Now to find fittings to convert the 10-32 to something more manageable.
allenb
Those valves may perform well for you. I'll be very interested to hear how it works for you. That's a fantastic price.

Let us know what options you come up with for the 10-32 to other adapting. I may have some ideas to add as well.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967

Quote

allenb wrote:

Those valves may perform well for you. I'll be very interested to hear how it works for you. That's a fantastic price.

Let us know what options you come up with for the 10-32 to other adapting. I may have some ideas to add as well.

Allen


I'd love to hear your ideas, my current plan is to use this valve http://www.clippa...art/TV-2SP as my on off valve so I can leave my needle fixed. So that has a 1/8" input so that's easy and the output is 10-32 so the needle valve can screw directly to the output of the valve. Then from the output of the needle valve I found a 1/8" to 10-32 brass adapter on Amazon that will then be adapted to 1/4 compression which is my runs to my burner. It's simple enough, eventually I'm going to move to a pid controlled solenoid high low setup, so I'll have to figure that out but that will be after I've worked out all the kinks of the current setup.

Royce
allenb
That looks like a great plan of action especially with the toggle on/off valve which I had never seen before. I'll have to remember that one on my next mod session.

One thing to consider when figuring out the valve mounting scheme is that a needle valve with 10-32 plumbing by design is just a snug fit as to not distort the o-ring and due to this, it can swivel when operated which can be annoying. Best practice is to either buy one with threaded holes for screwing it down to a bracket or to fabricate a bracket of sorts to affix it to it's intended location.

Something to consider for hooking your 1/4" tubing to the valve is this:

https://www.amazo...B00S838RD8

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967

Quote

allenb wrote:

That looks like a great plan of action especially with the toggle on/off valve which I had never seen before. I'll have to remember that one on my next mod session.

One thing to consider when figuring out the valve mounting scheme is that a needle valve with 10-32 plumbing by design is just a snug fit as to not distort the o-ring and due to this, it can swivel when operated which can be annoying. Best practice is to either buy one with threaded holes for screwing it down to a bracket or to fabricate a bracket of sorts to affix it to it's intended location.

Something to consider for hooking your 1/4" tubing to the valve is this:

https://www.amazo...B00S838RD8

Allen


Oh I love the idea of using the push connectors. Do you know if it will work with copper pipe? Everything I'm reading sounds like its made for a plastic of some kind.
Royce
Mustang967
Nevermind. I figured it out :)
allenb

Quote

Oh I love the idea of using the push connectors. Do you know if it will work with copper pipe? Everything I'm reading sounds like its made for a plastic of some kind.
Royce


That's a good question. I've used the nylon push fittings with 1/4" copper tubing for water with no problems. You need to make sure the tubing hasn't been rolled into a tight radius coil (less than a couple of feet). When it's been coiled too tightly it develops an oval cross section and would not work well. I've only used copper and push fittings for water to brewers so I would do one heck of a good leak test before leaving the propane on for very long. Also, do a pull test to make sure the internal barbs are able to hold the copper tubing securely as they do with plastic tubing. I've found that on occasion, copper can be difficult to release from the push connector and had to just cut the copper and toss the fitting.

With all that said, make sure you do ample testing for leaks before putting the plumbing into service. Only danger I had was getting me or my customer wet if it didn't work out but with propane you could remove buildings from foundations!

I would find a way to use nylon if it were me.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967
So I finally got all of the parts together and it's jury rigged for the time being but it works! With about 30 minutes of testing so far I'm very happy with the needle valves. The adjustability is fantastic especially when compared to my old cheap amazon valve.
https://www.amazo...&psc=1 This is the valve that I got and its fantastic especially for only being $14. So here is a quick video of my initial tests. I'll take more once my bench is cleaned up ;)

allenb
Nice valves and good to see you at this stage of the build. Can't wait to see the roaster come together. Keep us up to speed on progress.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967

Quote

Nice valves and good to see you at this stage of the build. Can't wait to see the roaster come together. Keep us up to speed on progress.

Allen


Thanks!! I feel like a kid on Christmas morning with this thing.

This video is of the temperature controller in action. I can't call it a PID as it's simply an Arduino if then statement with a little hysteresis added to try and reduce hunting. I might try to incorporate some actual PID code in the near future. I can't wait to button this thing up and get some more roasts under my belt. I've had 4 successful 12-16oz roasts and I can't wait to see how these new changes will improve the process.

I'm also attaching a graph from some tests that I was running earlier. The rate of rise code needs some help but I'm happy that it's working as planned.



Royce
Mustang967 attached the following image:
img_0939.png
allenb
Hi Mustang,

There's so many control options these days it can be a real task to zero in on what combination of microcontroller and interface one wants to use for their roaster. Make sure you take a good look at what Greencardigan has designed or contributed to. He's been a trail blazer and has designed excellent control options with PID functions already worked out.

Oh, we're going to need to see some video footage of your roaster above ankle level!

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Mustang967
So I just completed my first roast with the new needle valves and it was fantastic!
The new valves gave a huge amount of control that I never had before.
I roasted 17.1 oz of green in about 9.5 minutes and came out with 15.1 oz of roasted beans.

I don't know about you guys but I could watch roasting beans tumble all day long. So I took some slo-mo video :)



You can also see a little more of my roaster from this video, I'll take some more pictures or maybe some video with a bit more detail on the roaster soon.

This is from the roast today.
forum.homeroasters.org/forum/attachments/roast_chart.png

I need to learn a lot more about roast profiles!

Up to this point I had been using stock popcorn poppers and the ability to control aspects of my roast is amazing and completely foreign.

Royce
Mustang967 attached the following image:
roast_chart.png
Jump to Forum:

Similar Threads

Thread Forum Replies Last Post
Gas safety valve questions Building a Coffee Roaster 5 07/23/2021 7:17 PM
Question about TC4 ambient temperature/cold junction MCP3424/MCP9800 Dataloggers/Controllers/Rate of Rise Meters 5 03/27/2021 9:28 AM
Behmor 1600 question Roasting Coffee 11 03/15/2021 12:32 PM
Flow Meter/Needle Valve Combo Electric and Gas Heat Sources 5 08/19/2020 4:27 PM
Question for Gene Cafe Roaster Gene Cafe Roaster 5 06/08/2020 7:15 PM
Homeroasters Association Logo, and all Content, Images, and Icons © 2005-2016 Homeroasters Association - Logos are the property of their respective owners.
Powered by PHP-Fusion Copyright © 2021 PHP-Fusion Inc
Released as free software without warranties under GNU Affero GPL v3
Designed with by NetriX