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Old 03-21-2011, 12:57 PM   #1
meadowstream
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I have a RIMS system and am looking for a better way to dial-in the flow than I use right now.

On my 15g system, a March pump take wort from under the false bottom and then pumps it back into a circular tube immersed in the grain bed. The problem I sometimes have is too much suction resulting in a compacted grain bed and then some scorching. Suction/flow is controlled by pinching the outlet tubing from the March pump. I handle this by paying close attention for 20 minutes after dough-in, and when the system is dialed-in then everything is OK for the rest of the mash.

But, I would love to be more scientific, controlled and exact about this recirculation! The first thing that occurred to me was to find a rotameter with a valve. Does anyone know of an in-line liquid rotameter model with a valve that would suit - or another simple in-line mechanical measurement and control solution that would work?

Thanks for reading!

 
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Old 03-21-2011, 01:24 PM   #2
MalFet
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I can't quite picture how what you are describing would work...you're looking for a device that would regulate flow-rate in response to a measurement of flow-rate? Perhaps you could describe more specifically what you would like this device to do.

You might consider a manometer/vacuum gauge. It isn't an automated system, but I use a sight-glass to detect pressure changes in the space under my false bottom, and then adjust the ball valve on the output of my march pump accordingly.

 
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Old 03-21-2011, 03:27 PM   #3
meadowstream
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MalFet - thanks for your note. All I am trying to do is measure and control flow through a vertical tube without using electronics (or my uncalibrated plastic tube pincher.) A rotameter is what first occurred to me, and I will look into your manometer, too - thanks.

 
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Old 03-21-2011, 03:37 PM   #4
Catt22
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My solution was to install a vacuum gauge on the suction side of the pump. The gauge allows you to monitor and regulate the amount of suction applied to the false bottom. The gauge should read near zero or only a few psi max when the mash is flowing freely. Readings above about 2 or 3 psi indicate an increased resistance to flow and an impending stuck mash. A stuck mash is not a big deal at all. When it happens or just before, stop the pump, shut off the burner, stir the mash well then resume the circulation and heating.

I've found that the best way to control the flow rate precisely is with a gate valve. A gate valve is typically 3-1/2 turns to full open vs. 1/4 turn for a ball valve. It's makes a huge difference. I have a gate valve on the output of my pump and also one on the HLT for fly sparging.

I've found that the best way to avoid scorching is to use a flame tamer or a kettle with a clad bottom. My "flame tamer" is a solid copper disc 1/8" x 12" diameter. The flame tamer placed under the kettle distributes the heat and helps to minimize hot spots which is a notorious problem with SS kettles. A clad bottom serves the same purpose as a flame tamer or heat diffuser.

BTW, I'm running a direct fired RIMS.

 
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Old 03-21-2011, 03:39 PM   #5
Catt22
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Quote:
Originally Posted by meadowstream View Post
MalFet - thanks for your note. All I am trying to do is measure and control flow through a vertical tube without using electronics (or my uncalibrated plastic tube pincher.) A rotameter is what first occurred to me, and I will look into your manometer, too - thanks.
A manometer can be used the same way as a vacuum gauge. Some site tubes can work as a manometer if they are ported below the false bottom.

 
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Old 03-21-2011, 04:31 PM   #6
kladue
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You can use variable area flow meters from Dwyer like I have https://picasaweb.google.com/kevin.l...48447683664962, the left flow meter is for sparge and the right hand is wort flow. Keeping the flow units in GPH helps make flow matching easier. Skip the factory flow valve and use a ball valve for the flow control as the needle valve has a much higher pressure drop which will limit flow.
The flow meters have a temperature limit right at mashing temperatures but exceeding that has not been an issue because the pressure is so low in the brew system.

 
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Old 03-21-2011, 04:38 PM   #7
MalFet
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Quote:
Originally Posted by meadowstream View Post
MalFet - thanks for your note. All I am trying to do is measure and control flow through a vertical tube without using electronics (or my uncalibrated plastic tube pincher.) A rotameter is what first occurred to me, and I will look into your manometer, too - thanks.
Ah, gotcha...for some reason I had it in my mind that you were trying to automate.

Flow rate is probably not going to be the variable you actually want to track, as it is one step removed in terms of process from grain bed compression and stuck recirculations. Certainly, a slowed/stopped flow indicates that the problem is already happening, but if your goal is to catch it beforehand then tracking negative pressure under your false bottom is the way to go.

I'd hesitate to use a rotameter just because I'm not sure that the numbers would be useful for much. Different grist compositions will presumably get stuck or not at different flow rates, no?

 
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Old 03-21-2011, 07:15 PM   #8
kladue
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A 1 gpm/60 gph flow rate seems to work for all barley beers with a medium crush, for 60+% wheat beers a 125 degree protein rest is just about the only thing that keeps you from having a stuck mash every time.

 
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Old 03-22-2011, 02:32 AM   #9
meadowstream
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Catt thanks for your vacuum suggestion. Kladue, that is a nice-looking panel with mounted rotameters - and thanks for the flowrate suggestion (1 GPM seems high for my system, though - my crush seems medium...but I would guess good flow for me is less than 1/2 gallon per minute.)

Malfet, you are right that controlling off of vacuum makes more sense...but that would require taking apart hard-piped parts of my rig...while getting a sense of the range of flow rate that leads to compaction is easier because I can just stick a rotameter in the tubing that leads back to the rims tube.

 
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