Upgrading to RIMS, a few questions

[PaulHilgeman]

I am thinking of moving to a RIMS system, and have a few questions.

I currently batch sparge and use a toilet braid. I presume that this will work fine with the constant recirculation?

Are there any really good designs out there for a RIMS tube? I have seen several, but I am looking for something cheap, simple and easy.

I am assuming that since people can keep a mash temp stable in a kettle with a 1500W element, I should be absolutely fine doing the same thing in a cooler, the RIMS probably wont run that much at all, and I *might* even be able to do a mash-out.

I will be incorporating a flow control sensor at the inlet of the RIMS tube that will lock out the SSR when there is not any flow.

Thanks.

 

[Saccharomyces]

Easiest option for the RIMS tube is to buy one from this guy: https://www.homebrewtalk.com/f41/stainless-steel-rims-tube-176740/

Alternatively you can build one out of SS parts through mail order, there are several parts lists on this thread: https://www.homebrewtalk.com/f51/rims-dummies-114997/

I'm currently using my 1500W RIMS with a cooler. Heating for mashout is not a problem, the step rate is about 1*F per minute for a 10 gallon batch. With a 5 gallon batch it's 2*F per minute.

If you mount the RIMS tube vertically below the level of your MLT, and put the input at the bottom of the tube slightly above the input level of your pump, it should not be necessary to have any protection device because it is practically impossible to run the element dry (unless of course you manage to dry fire the element before priming the loop).

 

[PaulHilgeman]

I am more worried about walking away from the mash and getting a stuck sparge than anything. Then the wort in the RIMS tube would scorch.

How about the toilet braid, do I need to upgrade that if I am going to be constantly recirculating?

 

[dino2gnt]

I am more worried about walking away from the mash and getting a stuck sparge than anything. Then the wort in the RIMS tube would scorch.

No it wouldn't. The PID (or whatever you're using for temperature control) would bring it up to your set temp, and then maintain it there.

 

[JVD_X]

Easiest option for the RIMS tube is to buy one from this guy: https://www.homebrewtalk.com/f41/stainless-steel-rims-tube-176740/

With all due respect to pinupguy... too many people including myself have had elements rust away because they didn't get the inside of the RIMS dry after using it. Just a teeny little bit of water will cause the element bases to rust.

It is more expensive but using a rims tube that can be easily taken apart - like this one - is IMO a better approach.

 

[camiller]

As far as the hose braid goes, I'd think that if your drawing wort from too small of an area that you would get channeling issues and inconsistent dispersion of heat within the mash tun. You would be better off with a copper or cpvc manifold than the hose braid.

Edit: is just occurred to me that you haven't given a lot of information on you mash tun so my previous response is based on my cooler setup (I batch sparge) where a single hose braid running through the middle is fine. What have you got? cooler geometry (round, square, rectangle) Single run of hose braid or a lot? etc.

 

[PaulHilgeman]

No it wouldn't. The PID (or whatever you're using for temperature control) would bring it up to your set temp, and then maintain it there.

Ok, makes sense, then I guess I really dont need it in there.. Thats good to know.

 

[PaulHilgeman]

With all due respect to pinupguy... too many people including myself have had elements rust away because they didn't get the inside of the RIMS dry after using it. Just a teeny little bit of water will cause the element bases to rust.

It is more expensive but using a rims tube that can be easily taken apart - like this one - is IMO a better approach.

Ha! I am trying to get this whole project done for less than that!

I am going to start looking at Home Depot for ways to make this work, I am probably thinking copper.

 

[newrbrewer]

With all due respect to pinupguy... too many people including myself have had elements rust away because they didn't get the inside of the RIMS dry after using it. Just a teeny little bit of water will cause the element bases to rust.

It is more expensive but using a rims tube that can be easily taken apart - like this one - is IMO a better approach.

Either one will be a fine choice in the end. A little bit of high temp FDA approved silicone, around the base of the element, will inhibit the rust.

 

[Sawdustguy]

No it wouldn't. The PID (or whatever you're using for temperature control) would bring it up to your set temp, and then maintain it there.

dino2gnt your premise is totally wrong....Paul is correct in concerns and his use of a flow switch which will prevent an incident if he has a stuck mash. With the flow switch he can be confident he can walk away and not return to a burned up RIMS Hex. Read below from my RIMS for Dummies Thread.

I assumed that the temp. probe in the tube would keep the element from heating the fluid to a boiling temp. I mean, it is set at 155F or so? Wouldnt the chamber ONLY heat to 155F and therefore not boil off? I mean, in 15 seconds, wouldnt the PID shut off the element once the fluid reached 156F?

A PID doesn't work like that. You are thinking of a hysteresis/digital control.
PV>Set Point + dead band = turn off

The PID is calibrated to inject a continuous amount of heat at a given flow rate to maintain a temp. If you choke the flow completely off you are putting a lot of heat into a small volume of water. So the acceleration of the temperature is VERY rapid. When you auto tune a PID for a hex like this (at least in my experience) the derivative factor is very insubstantial. So with a weak derivative the predictive factor of the PID doesn't have much of an affect. If you will, the "Oh crap, I haven't hit my set point but I am going to overshoot," compensation.

The P variable will tell the PID to back off immediately but only a fixed (P)roportion of the error.

The I is a proportion of the error summed over time. So when you over shoot the I starts backing off more aggressively as more time goes by. It also increases the output over time if it isn't up to temp. Once you hit your temp the I value doesn't change because there is no error.

Here is an example of why you don't want the PID to turn off as soon as it gets to the set point. You need X amount of heat put into the mash to maintain a constant temp. If you turn it off right at the set point the temp will quickly start to fall. You want to be able to back off enough power to cause the temp to drop with out letting it crash. So you will still introduce some heat when past the set point.

So back to the small volume with lots of heat problem. Once the temp in the HEX starts to cool the PID will turn on again and cause the water to boil in about an instant, it maintains the heat injection profile based at the gpm it was tuned at. So it will continue to boil the liquid in the HEX until it reaches 0% output. Then the whole process will start over. A couple cycles of this will start to burn things up.

 

[JVD_X]

Ha! I am trying to get this whole project done for less than that!

I am going to start looking at Home Depot for ways to make this work, I am probably thinking copper.

My original RIMS was copper and it blew up (not because it was copper but because the pump dried out, causing the element to run dry, etc...)

Would not have had a problem with it except that it's difficult to take apart.

I would second the motion that you at least use piping you can take apart... but do so every time you brew.

 

[PaulHilgeman]

Thanks for all of the feedback guys. I really like this DIY forum, I havent posted here much, but I am a big DIYer.

I have ordered the pump, and will try to build the chamber this weekend.

My observations so far are:

1. Copper can be used, but make it dis-assebleable for cleaning. I am thinking that I should use NPT connections for the nipples in and out, and the 1 inch female connection will be plenty to promote drying.
2. Try the toilet braid but it might not work perfectly, so consider a copper manifold.
3. The flow sensing valve may not be completely necessary, but it will be nice and will provide some additional safety. At least I will know that when I turn the pump off, the element will be off, even when in an over-ride state.

 

[limulus]

Ha! I am trying to get this whole project done for less than that!

I am going to start looking at Home Depot for ways to make this work, I am probably thinking copper.

From what I have seen HD never has copper that large. I did see a guy who built a RIMS tube from PVC. He posted this about two years ago. It would be simple using a section of PVC, two Tees a plug for one end and a female threaded plug for the the element and a couple of barbs. I built one and from PVC and still have it, but never tried it. Here are a couple of pictures of what i built. It took about 5-min to assemble. The nice thing was my HD store has 2ft sections of PVC pipe so I did not have to buy a 10ft length to do this. I also bought an LD and a HD element. The LD element was touching the side a little, but the HD element does not. *Good flow would be important if using the HD element to avoid scorching. The one I built could be glued together everywhere but the barbs and the element plug. You could just unscrew them and then have better access for cleaning and drying the inside.

This a a thread with pics of another guy's RIMS. I believe he used his.
https://www.homebrewtalk.com/f11/mounting-heating-element-82497/

 

[PaulHilgeman]

Thats a really good idea, with some additional safety features, it would be a great solution.

I am thinking that if I use the flow switch AND a float switch in series with the SSR for the heater, then I will definitely be safe, a high temp SS float switch can be had for much less than the cost-savings of doing it out of PVC.

That way it would be impossible to turn on the SSR without having wort in the tube AND flow.

Thanks for the ideas!