View previous topic :: View next topic |
Author |
Message |
kennybrew
Joined: 16 Feb 2011 Posts: 5
|
Link Posted: Tue Mar 08, 2011 2:04 am Post subject: Controlling two fermentation vessels. |
|
|
I want to have 2 recirculating coiled fermentation vessels controlled by 2 controllers but through one source of heating/cooling. Firstly, I'm up North so I will be heating my fermentation for now. I have coils inside my fermenters and want to use a common heat exchanger for circulating heat around the two fermentors. Can I control the heat exchanger power from either AND both controllers? The power is from a single 120v circuit. I'd like to have the pump triggered by the controller/relay, then the heat exchanger kick on with a delayed relay(weak pump prime varification). Simple enough...but if I have 2 ferments going, can the second pump kick on and trigger the HE that's already on?
I guess what I'm saying is can two switches be used from a common source to power a single device? Hope that explains it OK.
Thanks. I know you EE's got this one!!
|
|
Back to top |
|
|
crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
|
Link Posted: Tue Mar 08, 2011 6:47 pm Post subject: |
|
|
Sounds like an interesting setup! Fermentation temperature control is by next project after completing the electric brewery.
I'm having trouble picturing one heat exchanger and two pumps. If the problem boils down to controlling one heat exchanger from the two pump control relays, then you can connect the switched "hot" side from both pump control relays in parallel to the coil of your time delay relay controlling the heat exchanger. That way, power is provided to the coil of heat exchanger time delay relay when either or both pumps are on.
The circuit will work like this: when the first pump is activated, the heat exchange time delay relay will close with a delay (weak prime verification). When the second pump is activated, while the first is still on, the heat exchange relay coil is already closed so the heat exchanger remains on.
Only when both pumps are switched off (by their respective controllers) will the heat exchanger also be switched off, and the next pump to activate cause the timer relay to close again (with delay.)
Words are not the best way to describe this. If it helps, I can try to throw together a picture.
_________________ ...just one more.
Last edited by crush on Wed Mar 09, 2011 12:08 am; edited 1 time in total
|
|
Back to top |
|
|
cardmechanic
Joined: 16 Feb 2011 Posts: 25 Location: Virginia
|
Link Posted: Tue Mar 08, 2011 9:33 pm Post subject: |
|
|
I'd suggest using a DC solenoid as a valve for each HE. Each controller can manipulate its own valve allowing for either/both operation.
|
|
Back to top |
|
|
kennybrew
Joined: 16 Feb 2011 Posts: 5
|
Link Posted: Wed Mar 09, 2011 3:09 am Post subject: |
|
|
That's what I thought Crush. Parallel, I'l have to remember that. But yea, you got what I was describing. Going to a single relay makes sense, too.
card, I was wondering if I had to valve it too. I'm not sure how the plumbing will work out just yet. I do want to use this set up in Summer too. Drawing glycol from a small freezer.
I may have found the ultimate solution, for me, on ebay today. We'll see when I get it.
I'll keep you posted but I must warn you.....I ferment in plastic bags. Not as pretty as stainless but don't laugh....it's paid for!
|
|
Back to top |
|
|
crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
|
Link Posted: Wed Mar 09, 2011 3:16 pm Post subject: |
|
|
plastic bags ... stainless - all the same to me, as long as it works, that's the main thing!
I'm still a bit puzzled by how two pumps feed one heat exchanger? Are the flows of the two pumps separate, or do they come together somewhere? If they are separate, then I don't think you need a valve, but if they are joined somewhere, then a valve will be needed to "isolate" each flow so that it's not affected by the other one. just bear in mind, I'm not much of a plumber, so I could be way off here.
_________________ ...just one more.
|
|
Back to top |
|
|
kennybrew
Joined: 16 Feb 2011 Posts: 5
|
Link Posted: Wed Mar 09, 2011 4:48 pm Post subject: |
|
|
You understood it perfectly in your first post. There would be two pumps that, when they get power, the heat exchanger would get power. MY OP was questioning the electrical part of the set up and now I understand that wiring in parallel would be OK.
My initial thought on the plumbing was that the fluid would flow to the path of least resistance. Both coils would go to the HE from a "t". When one pump is running, the "out" of the HE, or the "t" after it, would flow in the direction of the one pump's coil. When both pumps are on, they would battle for the HE "out" until one shut off. A solenoid valve would certainly allow isolating the two coils and may be the way to go. Or maybe a check valve on each before the "t" on the "in" side would be a simpler solution. Flow into the HE would be limited to the "on" pump(s).
If I do use solenoid valves, I suppose I would only need one pump and just control the direction of flow with the valves.
|
|
Back to top |
|
|
kennybrew
Joined: 16 Feb 2011 Posts: 5
|
Link Posted: Fri Mar 18, 2011 10:11 pm Post subject: |
|
|
OK, so I scored a temp. controller on Ebay that I thought was going to work out great for what I want to do. There are two Athena xt16 controllers in a box with relays and...well, it should work out fine for what I want to do. The problem is there's only one output on the controller. All the manuals say..."heat". My question, at this point, is can a PID be used for cooling only?...and then, when winter comes, re-program it for heat only? Seems that they're all designed for heat control unless they have a second (cooling) output. Can somebody set me straight on this?
Thanks.
|
|
Back to top |
|
|
crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
|
Link Posted: Sun Mar 20, 2011 11:40 pm Post subject: |
|
|
hi kenny,
Both the Auber PIDs and the Sestos (ebay from china) have a mode setting to select if they are controlling a cooler or a heater.
For the Auber it's the "cool" parameter, which selects the temperature unit (deg C/F) and heating/cooling - see section 4.14 in the manual, http://auberins.com/images/Manual/Manual%20version%203.4.pdf
_________________ ...just one more.
|
|
Back to top |
|
|
|
|