Building a glycol manifold - need help with simple problem

So I am building a glycol manifold because I have two fermenters now and need to chill both off my single glycol chilling unit. The pump is more than powerful enough to do so.

The plan is to use solenoids from valves4projects that will open when a temp sensor falls outside the setpoint and the fermenter needs cooling - pretty basic.

The problem comes when both solenoids are closed. The type of pump that is in the glycol chiller (and I can't change this) probably should not be deadheaded. So when both solenoids are closed, it needs to be following a loop that just circulates the chilled liquid right back into the return. So this way it will keep flowing and the pump will always be happy.

I know I can accomplish this via another solenoid that is energized open (as opposed to buying an expensive N/O solenoid) until one of the other solenoids opens up. But I think there must be some kind of mechanical solution that I am completely missing. Maybe something that senses some kind of pressure build up and automatically opens up or maybe there is just some way I need to plumb this alternatively.

Here's a visual pic of the "manifolds":




Top is simply a return manifold. Bottom comes in from the chiller and has two outputs for the fermenters.

Thanks in advance!

Anyone have any ideas??

Either an orifice plate that allows a constant minimum flow or a check valve that will bypass once enough pressure has been built after the two solenoids close. With some relays you could only power the pump when the solenoids are energized, but that may interfere with the cooling if the pump runs while the glycol is being chilled.

jcaudill said:

So I am building a glycol manifold because

The problem comes when both solenoids are closed. The type of pump that is in the glycol chiller (and I can't change this) probably should not be deadheaded. So when both solenoids are closed, it needs to be following a loop that just circulates the chilled liquid right back into the return. So this way it will keep flowing and the pump will always be happy.

Click to expand...

But I think there must be some kind of mechanical solution

Click to expand...

Most commercial chiller systems are supplied with an internal pressure bypass valve.
Install an adjustable pressure bypass valve at the end of your supply. These adjustable valves will bypass flow from your supply to your storage tank.

I know I can accomplish this via another solenoid that is energized open (as opposed to buying an expensive N/O solenoid) until one of the other solenoids opens up.

Click to expand...

My set-up uses a motorized bypass valve which is controlled by a logic controller.
I like more the technical challenge










Supply on the left, return on the right



Cheers,
ClaudiusB

ClaudiusB said:

Most commercial chiller systems are supplied with an internal pressure bypass valve.
Install an adjustable pressure bypass valve at the end of your supply. These adjustable valves will bypass flow from your supply to your storage tank.


My set-up uses a motorized bypass valve which is controlled by a logic controller.
I like more the technical challenge

Supply on the left, return on the right

Cheers,
ClaudiusB

Click to expand...

Thanks for the detailed reply! I am finding all kinds of different ways I could go about this. One is using a check valve with a cracking pressure that allows the recirc to function when pressure is too high. Another is using a pressure switch that basically does the same thing except it actually energizes a solenoid when actuated.

One of the problems I'm finding is knowing what to search for. You said adjustable pressure relief valve. Are you talking something like this: http://straval.com/catlist-relief-valves/CKV-05? That is what I'd call a check valve.

On your motorized solution - can you explain what is going on there? It sounds like you're doing something like I mentioned above but I'm not quite sure. I tried to search on that Erie component but couldn't find much.

I noticed one other weird thing last night. I hooked up a part of the manifold I showed above last night, except it had one input, and one output and I put a pressure gauge at the end because I wanted to see what the pressure was when the pump was deadheaded and when the output was hooked up to return to the chiller. (The answer was 9 psi when deadheaded and around 3 when not). The weird thing though is it was doing something strange to my pump which is a recirculation pump (has the agitator attached to the bottom to stir the glycol bath). After I shut the chiller off, if I turned it back on the pump wouldn't work. I have to open the top of the chiller, and manually turn the agitator with my hand and that must have freed something up because next time I turned it on all was well. But then next time it would be back to not working and I'd have to do the same thing. So instead of using the manifold I just hooked it up to my immersion chiller to make sure everything is ok and this problem disappeared. So best I can come up with maybe the flow was backing up against the agitator motor and binding it up? I don't know what about that manifold design would cause that unless it had something to do with the pressure gauge.

All help is very much appreciated!

One more question for you too: I realized I can't use those solenoids for this. The opening is too small. What are you using for a solenoid or actuator type valve? Thanks!

You could put the solenoid valves on the outlet of your ferms rather than the inlet. You could add a ~4lb check valve that would put a slight load on the pump, but when the solenoid valve opens you'll have a lower resistance loop through the ferm.

Thanks for the reply! What would moving the solenoids accomplish? Just curious. I did order new solenoids yesterday that have much larger orifices - so that problem is taken care of. I just need to handle the check valve now.

This leads me to two questions:

1) Finding a 4psi model is a bit tricky. I'd have to get a custom one made I think?
2) Should I put a low pressure check valve on the outlet of the pump to prevent backflow? Seems like that could potentially be an issue as well.

Thanks again!

So I ended up ordering a 5psi cracking pressure check valve last night, in 3/8" that I'll end up reducing down but the orifice was much bigger on the 3/8" that the 1/4" so the check valve should not impede flow.

I just need to know if I should put a check valve near the pump outlet, or inlet to the manifold as well so that there is no backflow.

Thanks guys!

I would wire a simple DPDT ($5.00) relay to you selenoids that will shut the chiller off when both valves are closed. KISS and save power.

It's a good idea.. but unfortunately not possible The chiller and pump have to stay on. Both are responsible for keeping the bath chilled (the pump has an agitator to keep the bath evenly distributed and from freezing).

I'm not familiar with chillers’ so I’m shooting in the dark but if the chiller is off how can it freeze? I know there will be a lag in getting the glycol up to temp but fermentation temps rise slowly and the chiller should have no problem keeping up. You should be able to set you parameters on your PID to avoid short cycling.

ClaudiusB said:

Most commercial chiller systems are supplied with an internal pressure bypass valve.
Install an adjustable pressure bypass valve at the end of your supply. These adjustable valves will bypass flow from your supply to your storage tank.


My set-up uses a motorized bypass valve which is controlled by a logic controller.
I like more the technical challenge

Supply on the left, return on the right

Cheers,
ClaudiusB

Click to expand...

Nice work man! Love the controls.

MaxOut said:

I'm not familiar with chillers’ so I’m shooting in the dark but if the chiller is off how can it freeze? I know there will be a lag in getting the glycol up to temp but fermentation temps rise slowly and the chiller should have no problem keeping up. You should be able to set you parameters on your PID to avoid short cycling.

Click to expand...

Let me explain a bit further.

I have a powerpack glycol chiller. It has a very small bath - about 2.5 gallons. It has a pump that serves two purposes - agitates the bath and circulates the glycol mixture. The pump is powered, probably by a simple relay, directly by the chiller. The chiller then is powered by plugging into the wall. Ok so that is the foundation.

Based on your thoughts - my initial thought was sure you could do that with the chiller, but then depending on how long the chiller is off with such a small bath it could be subject to a decent amount of thermal loss within relative short order - especially in the warmer months.

Then I thought well maybe just do it to the pump only which would also solve the problem. But since I mentioned the pump is also responsible for the agitation of the bath, that probably is not a smart move either.

I certainly like the thought of it not running 24/7 though What I may need to do is test how much it loses. Get it down to 35 or something then shut it off for 30 minutes and see what the loss is like.

jcaudill said:

Let me explain a bit further.

I have a powerpack glycol chiller. It has a very small bath - about 2.5 gallons. It has a pump that serves two purposes - agitates the bath and circulates the glycol mixture. The pump is powered, probably by a simple relay, directly by the chiller. The chiller then is powered by plugging into the wall. Ok so that is the foundation.

Based on your thoughts - my initial thought was sure you could do that with the chiller, but then depending on how long the chiller is off with such a small bath it could be subject to a decent amount of thermal loss within relative short order - especially in the warmer months.

Then I thought well maybe just do it to the pump only which would also solve the problem. But since I mentioned the pump is also responsible for the agitation of the bath, that probably is not a smart move either.

I certainly like the thought of it not running 24/7 though What I may need to do is test how much it loses. Get it down to 35 or something then shut it off for 30 minutes and see what the loss is like.

Click to expand...

Based on your description above I would interrupt the main power to the chiller. Depending on the ambient temp where the chiller is located I would be surprised if there was any significant loss. The small bath may add up to a quicker loss but also adds up to a quicker recovery. Keep in mind the thermal mass of glycol is denser than water so it will retain the temp longer and also should never freeze. Glycol is antifreeze. I’m sure the agitator is to smooth out stratification. Not sure what styles of beer your brewing or the capacity of your chiller but even a lager at 50 degrees should be a piece of cake.

Hmm - this is certainly worth considering. Would require a bit of extra programming (I'm building an Arduino based controller) but it would work I think! Thanks.