Flow meter into HLT to control water volumes

[mattd2]

I need to get around to etching my keggles to give me some way to check volume, but then I had an idea that I'd like to run past you guys to see if it would be feasible.
I batch sparge a so I basically heat 2 batches of water for the mash (strike & sparge) and base this on the grain weight including an estimate for absorption. I don't stop sparging when I hit my target volume, just get all of the batch sparge out. Then boil with a generally steady boil off rate throughout the year.
So what I am thinking is using a flow meter and solenoid valve on the cold water into my HLT, and batching in the required volume for strike water, and then sparge water once the mash has started. (Arduino controlled by the way)
Anyone see an issue with the plan?
Cheers

 

[BrunDog]

No, other than that Hall effect turbine/paddle flowmeter are not that accurate.

-BD

 

[JonW]

You can actually accomplish fairly accurate fill volumes with a simple timer. The only variables involved are pressure, orifice size and time. If you use a fixed orifice like a shower flow restrictor of about 2 - 3 mm, you can then do a timed fill. If your water pressure fluctuates, you can then add an inline pressure reducer to keep the flow at a constant pressure.

I use this valve (it has a built-in 2.5 mm restriction): http://www.ebay.com/itm/1-4-NPT-Ele...-DC-12VDC-N-C-RO-Air-Water-BBTF-/290723310425

I get a flow of 1 gallon in 55 seconds. I had all intentions of adding a pressure regulator to ensure that the flows were accurate at any pressure, but so far, I'm seeing very little fluctuation. I use my BCS controller to do the timing/filling.

 

[ryane]

It not that difficult to do what you propose, it is essentially what Im doing as well as another very well documented build (bucks electric brewery) on here. Though I using an arduino may be a bit more difficult than using a PLC off of ebay.

You can get brand new flow meters for ~100$ or less if your watching at the right time.

 

[mattd2]

It not that difficult to do what you propose, it is essentially what Im doing as well as another very well documented build (bucks electric brewery) on here. Though I using an arduino may be a bit more difficult than using a PLC off of ebay.

You can get brand new flow meters for ~100$ or less if your watching at the right time.

Using an arduino compared to a PLC shouldn't be more difficult... just different. I was thinking of using one of the cheap paddle wheel flow meters which are generally listed at 3% accurate in their mid-range, but I have seen some details (which I can't find now) indicating that this is out of the box and repeatability is pretty good on them so if you set them up, calibrate and don't move them the accuracy can be a damn sight better than 3%.

 

[thekraken]

(deleted - double post)

 

[thekraken]

Since you’re going the arduino route you might consider a pressure transducer instead: http://www.brewtroller.com/index.php?option=com_content&view=article&id=25&Itemid=407

http://www.digikey.com/product-detail/en/MPX5010DP/MPX5010DP-ND/464054

Cheap too.

I use one of these cheapo flow meters for my RIMS system (arduino controlled). I've found that it has to be recalibrated from time to time but once it is calibrated it's reasonably accurate, I think it might be accurate enough (for me) to measure out brewing liquor volumes. (Come to think of it I haven’t tested its calibration at different temperatures) Checking calibration only takes a minute or two, recalibrating only take a couple more minutes and move on with the brew day.