Im in the process of building a RIMS system and as a safe guard I would like to have a field sensor that would detect flowing wort after exiting the RIMS tube. The signal would pull in a relay or contactor to allow power to the element. Ive read a little about the hall effect sensors but I just want a yes or no signal to drive a relay.
Flowing wort signal for firing element
- Thread starter Earl_Grey
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augiedoggy
Well-Known Member
look at my Build thread below... I used a stainless reed sensor to do exactly what your asking but I also use 24v dc pumps so I only recirulate at 2GPM or less. I did have to de some minor modifications to the flow switch to allow more flow when open. it has saved me more than once now.
I just have my temperature probe in my RIMS tube. If the wort isn't flowing, it isn't going to take long for the temperature of the wort to go up, causing the PID to cut power to the element and the alarm to go off.
Which PID controller has this functionality?
All of them. It's what they do. When the temp reaches the set point, it cuts power.
augiedoggy
Well-Known Member
The issue is that not all rims setups have the temp probe right next to the element. good ones do. If you have say a 22" long rims and your element is only 12" long, When the flow stops you scorch fast and the damage is dont by the time the liquid at the other end heats up to the correct temp... ask me how I know... had that happen on my very first rims build.
The other scenerio is you shut off or drain the rims but forget to kill the element power... so you dry fire and burn it up. this is what I have alsmost done a couple times.
The other scenerio is you shut off or drain the rims but forget to kill the element power... so you dry fire and burn it up. this is what I have alsmost done a couple times.
If that is the case then you built it wrong and your control system will not do its job.
augiedoggy
Well-Known Member
Very true that its not ideal but it still works that way and theres a lot of folks with commercial rims tubes and this type of setup (1500w 120v elements) as well as rims with 240v 5500w lwd elements that can start to scorch in a rims tube in a very short time without flow.
If my temp probe were any closer to the end of my element they would be touching but it doesnt stop the possibility of dry firing. plus Ive found that if I bypass the safety cutoff and stop the flow even for say 10 second the liquid in my rims becomes WAY over temp before the pid sees it and shuts it off. It cost me about $15 to implement the flow switch and the wiring so for me it was worth it.. At the time there were all kinds of anti rims naysayers talking about the dangers of the pressure building up and the rims exploding.... It seems no matter what one does there will be people who feel negatively about it here so whatever. I posted my take for what its worth as someone who has built and tested 4 different rims configurations and wanted to feel safe walking away from my rig while its running this is just another layer of safety check for me.
I gotta strongly agree with augiedoggy on this one.
Regarding on a full (wet) tube, counting on your PID to catch an overtemp is an invitation to learn the definition of Murphy's law. And I guarantee it won't work with a horizontal mounted tube.
Regarding a tube that doesn't fill and heats dry... I don't care how well you designed your system... upstream and downstream hindrances will occur (like you forgetting to open a valve) or a pump loses prime. Trust me, this happens when you least expect it.
Absolutely put a flow switch inline with your low voltage side circuit. I personally use a flowmeter/Arduino/BCS ladder logic combo which prevents the output to the RIMS SSR from being powered if flow is not in a defined range. I can't count how many times this has saved my and my wort's arses.
Regarding on a full (wet) tube, counting on your PID to catch an overtemp is an invitation to learn the definition of Murphy's law. And I guarantee it won't work with a horizontal mounted tube.
Regarding a tube that doesn't fill and heats dry... I don't care how well you designed your system... upstream and downstream hindrances will occur (like you forgetting to open a valve) or a pump loses prime. Trust me, this happens when you least expect it.
Absolutely put a flow switch inline with your low voltage side circuit. I personally use a flowmeter/Arduino/BCS ladder logic combo which prevents the output to the RIMS SSR from being powered if flow is not in a defined range. I can't count how many times this has saved my and my wort's arses.
Get a longer probe.
I did this once. I blame myself for not following my own standard operating procedures.
The way i'd do this would be to use a rotameter and a proximity switch. I'd use the prox switch to "see" the float, which in turn would control a relay whos contacts were wired in series to the control side of the SSR. That way if flow is under your set rate, the relay would be open and even if the PID was asking for power, it couldn't give it.
Extra benefit too - you have a rotameter as part of your system, which i find to be incredibly helpful with a PID since the loop tuning is so dependent on the flow rate. Also helps alert you to an impending stuck sparge because it'll start to drop before you actually stick.
Extra benefit too - you have a rotameter as part of your system, which i find to be incredibly helpful with a PID since the loop tuning is so dependent on the flow rate. Also helps alert you to an impending stuck sparge because it'll start to drop before you actually stick.
augiedoggy
Well-Known Member
This is in fact in function the way mine is set up. The float is a reed switch though.. along with an audible alarm if the rims is out of the desired temp range.
