# Flow meter with solenoid



## wildburkey (29/9/15)

http://www.ebay.com.au/itm/G1-2-Water-Flow-Control-LCD-Display-Flow-Sensor-Meter-Solenoid-Valve-Gauge-/141005562888?hash=item20d4962408
Just wondering if anyone here has had a play around with anything like this? I thought it's be cool to set flow from HLT prior to brew, then set volumes for mashing, spargeing etc. I'm still yet to even do my first AG so not even going to consider going here yet but might look into playing with these later down the track. I was thinking if you can hook 2 solenoid vlaves up one between the HLT and MT, and another between the MT and BK this would work a treat for fly sparging if calibrated properly.


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## real_beer (29/9/15)

If you buy me one I'll run some detailed tests and let you know! I'll PM you my details if you decide to go ahead. Apart from your outlay for the unit my testing will be free.

Cheers


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## kunfaced (29/9/15)

If you integrate

http://www.ebay.com.au/itm/Digital-PID-Temperature-Controller-max-40A-SSR-K-Thermocouple-0-400-/171853633792?hash=item2803465900

with the solenoid, you could have yourself a fully automated fly sparge


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## Dips Me Lid (29/9/15)

Hey mate, solenoids aren't really designed for flow modulation, they're either on or off, which is not good for your pump.

Modulating actuators that control a valve body might be more what you're looking for, bearing in mind you'll need a controller to operate them, a PLC, DDC etc.

I personally prefer the simplicity of manual valve operation, but there's plenty of options out there for you.


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## wildburkey (29/9/15)

lol, I think I'll be right to test it out real _beer, yeah that was what I was thinking kunfaced. I have a stc hooked up to my HLT but you would have to calculate temp adjustments in the MT  Cheers guys, just thought I'd throw the idea out there.
Hey Dips, I am using gravity so it would just be a matter of using the flow meter to manually adjust the valves before brewing. Cheers for the input, I reckon I'll start out manual then play with this.


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## Dips Me Lid (29/9/15)

Sweet, that setup might be workable with gravity, definitely worth a crack.


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## wildburkey (29/9/15)

Another foreseeable problem with calibration is accounting for difference in flow with mash thickness. (I'm not even sure if viscosity would make a difference)


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## real_beer (29/9/15)

I was checking the accuracy of one of my digital scales yesterday in one litre increments to see how close they got to 1kg for every litre of water added to my 20lt bucket. They worked great but the automatic shutoff kicking in after two minutes was a real pita, That was using them with the battery mode, maybe they'd stay on permanently using the power adapter,

But it's definitely a quick way to measure your water volumes accurately.


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## desitter (5/10/15)

I'm working on a project currently that uses load cells to gauge real-time volume in my HLT, Mash and Boil kettle. I think it's a more elegant solution than a flow meter (though quite a bit more work to set up), as you can not only gauge the rate of change of volume/mass from one vessel to another, but also your boil-off rate, and total volume/mass in each vessel. Hence doing away with sight glasses, dip sticks etc. and calculations for thermal expansion (as mass is obviously not a function of temperature). All you really need hardware-wise is a few half-bridge load cells and a micro-controller. Be aware that Arduino's only have a 10 bit ADC, so you'll likely need to get a discreet external ADC and instrumentation amplifier to see the kind of accuracy and tare functionality require. (I'm playing around with the HX711 at the moment, which is a 24 bit ADC with a 128 gain amplifier, and is looking pretty good for the task)

Just something to consider.


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## jibba02 (6/10/15)

desitter said:


> I'm working on a project currently that uses load cells to gauge real-time volume in my HLT, Mash and Boil kettle.


Good idea. But dont forget, the weight of the wort changes as the SG changes. Albeit not enough to worry about. But if you wanna get picky 

I have a water flow meter, same as above, to measure from HLT to Mash only. I always fly sparge and take pre boil gravity readings. So have no need to measure other volumes.


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## jibba02 (6/10/15)

Oh and the minimum flow rate for the above unit is 1 l/min. Way too fast for fly sparging


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## MHB (6/10/15)

desitter said:


> I'm working on a project currently that uses load cells to gauge real-time volume in my HLT, Mash and Boil kettle. I think it's a more elegant solution than a flow meter (though quite a bit more work to set up), as you can not only gauge the rate of change of volume/mass from one vessel to another, but also your boil-off rate, and total volume/mass in each vessel. Hence doing away with sight glasses, dip sticks etc. and calculations for thermal expansion (as mass is obviously not a function of temperature). All you really need hardware-wise is a few half-bridge load cells and a micro-controller. Be aware that Arduino's only have a 10 bit ADC, so you'll likely need to get a discreet external ADC and instrumentation amplifier to see the kind of accuracy and tare functionality require. (I'm playing around with the HX711 at the moment, which is a 24 bit ADC with a 128 gain amplifier, and is looking pretty good for the task)
> 
> Just something to consider.


At some point you will need a volume measurement to derive density, or some way to measure density directly.
Without that knowing the mass anywhere/everywhere in the system tells you jack
Mark


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## desitter (7/10/15)

The plan was for system to have a touchscreen to display the volumes/rate of change of volume, and allow the input of refractometer samples to account for density changes. Though I haven't designed the software required for the task, hence haven't thought about all the specifics in detail.


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## MHB (7/10/15)

Oh good, if you come up with a reasonably priced SG/OP measuring sensor - please let me know.
Mark


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## husky (13/10/15)

Likewise. Im also in the market for an analogue sg meter that can put out 4-20mA. Sg meter and load cells would be awesome. Got any info on your load cells? Do they require only one analogue input per set of cells or one per cell?


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## desitter (13/10/15)

> Got any info on your load cells? Do they require only one analogue input per set of cells or one per cell?


At present I'm just using some 25kg half-bridge cells from Ebay. If you're unfamiliar with a Wheatstone Bridge configuration, take a look at the wiki, that should clear up any questions with regard to inputs.

In short though, each half cell is essentially a Voltage Divider, where a change in resistance across R1 (in this case a Strain Gauge) results in a change of voltage across R2 which is in series with R1. Each cell makes up half of the complete Wheatstone Bridge, with three wires, a + and - excitation wire, and a signal wire. It's only a matter of finding the voltage differential between the signal wires of any two half cells. Typically you would use an op-amp, or preferably an Instrumentation Amplifier to do this, while also rejecting common-mode noise in the signal and amplifying it to something usable, as the rated output of any one cell is only around 1mV per excitation volt.

In-amp's will normally have two differential inputs (one from each half cell) and one output (this being the difference between the two input signals), which you would then run to your ADC. Hence each full-bridge configuration, whether comprised of 2 half cells, or a single full bridge cell (these will naturally have 4 wires instead of the half cells 3), will ultimately need its own analog input.

I find AD623's to be a good single supply in-amp if you're looking to go that route. But it would probably be easier to buy something specifically made for the job, like the HX711 which has a programmable gain amplifier and ADC all in one package, as well as two sets of selectable differential inputs. Though in this case I wish the max gain was more than 128.

Feel free to message me if you need assistance.


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