Exactly. For the dampers I've made, the valve is the limiting cross section.
EDIT: To clarify the above statement. I don't want to do anything to decrease the valve CSA since it is always much smaller than my output CSA.
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The Adapt-a-Damper - Open Source Project
- Thread starter WBegg
- Start date
Exactly. For the dampers I've made, the valve is the limiting cross section.
EDIT: To clarify the above statement. I don't want to do anything to decrease the valve CSA since it is always much smaller than my output CSA.
I'm not good with EE so I leave that stuff to others, but if someone could make the HM use a stepper I would be extremely happy. I have a couple of CNC'd aluminum sliding door damper designs that I would love to use with a threaded rod system as opposed to a servo/arm setup.
I agree, Tom. I'm losing about 50 mm2 by switching to this profile, which may or may not make a huge difference. Maybe it's a moot point to try to change the profile anyway. After all, we're making BBQ, not building rockets.
EDIT: 30mm2 difference (861 vs 891)
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SteveCK
TVWBB Pro
The Sunon blower that you are using pushes at 16.8 mm-Aq. At that pressure and with the amount of cross sectional surface area on your valve, the 30mm2 difference is negligible. At that point I find it worth going with a linear intake as there are huge percent errors associated with that shape of opening once you go from 50% open down to the closed position. There is no reason to introduce more error in the already complex process the HeaterMeter is trying to control.
Dave Smith
TVWBB Super Fan
Yeah, you're probably right. I have a 3hole variation of the damper (in the posted .3dm files, See CHeatham's milling) that exceeds the CSA of the original, but it introduces 2 more issues.
1: The servo total angular movement is reduced, thus effectively reducing the "resolution" of the servo. You might have some insight on this, Steve, as your micro and macro dampers use this style.
2: Any error (a small crack in the fully closed position) will be multiplied by 3.
Maybe i'll test the two with real time cooks, as Tom suggested, to get some real data.
SteveCK
TVWBB Pro
1) I did some research on this a while back when someone on this forum claimed I was stealing his damper design. Although you are reducing the resolution when you add more intake holes I ultimately decided the error associated with resolution loss was less than the error introduced with the "smiley face" design. You also need to take into account that your damper should be running in the low percentage areas and with the "smiley face" that is where all your high percent of errors are found. The MacroDamper I designed is large enough that I could use 1 hole and allow for a larger range of motion with the servo, so it is much more accurate. I'm not exactly sure how large your damper is, though I do own a RD3 (that now just sits on a shelf) and when I look at it it seems like to make it linear you would have to loose 25%-30% of your CSA of flow.
2) I have yet to see my damper fail to fully close, so I don't think this is a problem. I also only use SG90 servos now because I think the QC is much higher on them. The MG90s are where the big bucks are to be made because the most common use for these servos has been RC Airplanes. There was a high demand for a metal gear servo for durability and that produced knockoffs and lower QC. As far as I know this hasn't hit the SG90s, and I say that only because of the more than dozen or so I've played with they were all smooth, apparently accurate, quiet, and not a single one had the delirium tremens or were DOA.
All-in-all though, I don't think it makes a huge difference in the cooks both ways have it's inaccuracies. Personally, as an engineer, I find a linear intake to be the better of the two (as long as you know you have enough CSA of flow [CSAF]) because when designing the intake you have to make the assumption that the controller will put the valve in the correct position. If I make the assumption that the valve will be plus/minus X-deg then why would you use the "smiley face"? You already know that design is inaccurate already, why introduce more inaccuracy? I guess one could hope that 50% of the time the servo inaccuracy makes it land in the proper positions for true linear output, but the other 50% of the time it throws it way out of bounds.
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SteveCK
TVWBB Pro
Shoot me an email anytime you need anything. I'm a big fan of yours.
After a nights sleep, a simpler way of putting it is that with the linear design you will have a smaller standard deviation than with the "smiley face". But I think my long hand made that point. Cheers Will
After a nights sleep, a simpler way of putting it is that with the linear design you will have a smaller standard deviation than with the "smiley face". But I think my long hand made that point. Cheers Will
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With some convincing from Steve, I've created a 2 hole option for the adapt-a-damper (yeah, I was inspired by the MicroDamper design). It has a few advantages that include:
1. A greater Cross Sectional Area. Increased from 891 mm2 to 1304 mm2, or a 46% increase in total from the original "smiley face" design
2. It's linear. If the HM tells it to open 50%, it opens 50%.
I'll post to Thingiverse once I clean some stuff up a bit.
EDIT: It's now posted with the other files. http://www.thingiverse.com/thing:1194140
1. A greater Cross Sectional Area. Increased from 891 mm2 to 1304 mm2, or a 46% increase in total from the original "smiley face" design
2. It's linear. If the HM tells it to open 50%, it opens 50%.
I'll post to Thingiverse once I clean some stuff up a bit.
EDIT: It's now posted with the other files. http://www.thingiverse.com/thing:1194140
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Sorry Chris, I missed your post about a month ago. Regarding mounting to a board, what would you think about maybe a clip system, where you could clip the adapt-a-damper into a plate bolted/screwed to a fixture? The cheater fix would be just to design some counter-sunk screw holes in the bottom of the case, but because this is more of a modular system, maybe a removable clip-in system would be better? Let me know what you think. I think it's a great idea you have.
Cheers,mate.
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I've put together a video of how the Adapt-a-Damper goes together, and how it could become a true open source modular system. I like DavidNP's work he's been doing with the ESP8266, so maybe he can come up with a use for the case other than the TC board (coming). I was thinking of doing a simple switch with LEDs to switch between "Fan Only", "Damper Only", or "Fan and Damper".
https://www.youtube.com/watch?v=NSa-UM9ffoU
https://www.youtube.com/watch?v=NSa-UM9ffoU