RIMS Flow Rate

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Haggismaximus

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So we finally got around to doing a test run on the Brewatron and everything seemed to work out great accept a high amount of heat loss in the RIMS cycle.

What type of flow-rate are you guys using for your when in RIMS recirculation? For our initial test we had it restricted out pretty low, not quit a trickle, but a gallon every few minutes or so. We have a lot of stainless line in our system, so I'm thinking pushing it through so slow is letting it radiate a lot of heat.

Them temp differential between the bottom of the Mash and in input to the RIMS tube was about 4-5 degrees. I just checked out the video of the Sabco Brew Magic and and our recirculation is no where near that fast.
 
I circulate as fast as possible. I haven't actually measured the flow rate, but I would estimate that it's probably about 1-1/2 gpm or so, maybe a little more. Fast circulation will allow you to apply more heat when ramping up the temperature, however, there's a fine line between fast and too fast. Too fast and you risk compacting the grain bed as someone previously mentioned. Not fast enough and it will take forever to raise the grain bed temp.
 
Thinner mash = faster flow. I can run mine all out with no issues. Using 1.5q/lb.

IMO, if you pump fast enough you can compact the grain bed regardless of how thin the mash is. The "all out" term will vary radically depending on system design. My "all out" rate would probably be close to 5 gpm and maybe more. I'm not sure as I've never actually measured it, but also it's pretty much irrelevant as I could never pump that fast anyway. If you are pumping "all out", you must have a lot of resistance in the circuit. Pumping through small hoses and long hex coils can reduce the flow rate substantially. Running "all out" might be the only way to get a reasonable flow if there's a lot of resistance in the circuit.
 
Does anyone use an in-line flow rate meter?

I am not aware of anyone who uses in in-line flow meter. The ultra sonic type would be expensive and the propeller type would probably be susceptible to plugging. That, and they would not be all that useful IMO. It's not hard to just eyeball the flow rate and make adjustments as needed.
 
Does anyone use an in-line flow rate meter?

I use an analog flow switch I purchased on eBay for $25. Switching range is 0.25 gal/min - 16 gal/min. No plugging issues.

It's set to open the RIMS PID circuit when the flow drops below 0.25 gal/min.

I acquired a digital flow switch/meter for free a while back, but it's BSP thread and the BSP-to-NPT adapters are $$$.
 
I use a Dwyer VFB 81 (6- 60GPH) flow meter in the old R&D unit and an electronic flow meter in the newer automated system. Wort pump discharge goes through flow meter for flow and color/clarity monitoring while mashing on old system. Here is a picture http://picasaweb.google.com/kevin.ladue/Flowmeters#, left hand flowmeter is water flow to boiler, right hand meter is wort flow from pump. This picture was taken during a superheated steam injection heating test with water a couple years ago to demonstrate wort heating ability to brew club members, 36 degree rise at 50 GPH/.83 GPM.
 
I use a march pump and I recirc with the valve wide open The faster you can turn over the fluid in the mash tun, the more accurate your temps will be. I start out slowly and keep opening the valve. I've probably done 50 or more batches this way with no stuck mashes.

Linc
 
I use a march pump and I recirc with the valve wide open The faster you can turn over the fluid in the mash tun, the more accurate your temps will be. I start out slowly and keep opening the valve. I've probably done 50 or more batches this way with no stuck mashes.

Linc

The wide open flow rate on one system can be, and usually is, much different than that of another system. There is no way that I can run wide open; at least not for very long. I have not measured the flow rate, but I run as fast as possible and I would estimate it at between 1 and 2 gpm. Next time I brew I will measure the flow rate.
 
Hose sizes and lengths are going to change how much we flow we get. I was just offering up that I have no issues with a march pump running full throttle. This has remained true through many major re-designs of my system. I use all 1/2 in hosing, 1/2 in fittings etc. Total hose length on my mash system is less than 8 ft.

Linc
 
Hose sizes and lengths are going to change how much we flow we get. I was just offering up that I have no issues with a march pump running full throttle. This has remained true through many major re-designs of my system. I use all 1/2 in hosing, 1/2 in fittings etc. Total hose length on my mash system is less than 8 ft.

Linc
It depends on your gain to strike water ratio, false bottom etc. The message is that there are more variables than you realize.
 
It depends on your gain to strike water ratio, false bottom etc. The message is that there are more variables than you realize.

The water to grain ratio makes very little difference in the flow rate on my RIMS system. I normally dough in at 1.25-1.5 qts/lb. Most often right at 1.5. Occasionally I will cut back the ratio to 1 qt/lb if I get short on room in the MT which sometimes happens with a high gravity brew. At these ratios, there seems to be plenty of free liquid to pump and any change in the wort viscosity is very minor. My hoses are 5/8" ID with nothing less than 1/2" ID anywhere in the circulation system. I keep the hoses as short as possible to minimize frictional losses. I have a full false bottom in my MT, so that variable is pretty well fixed and maxed out. I do not think that there are more variables than I realize. I've been working with my system for a very long time and I think I've pretty much got everything figured out. IMO, the limiting factor when pumping the wort is how much suction I can apply to the grain bed, not the pump, the hoses, the fittings, the water/grain ratio or anything else. The wort can only flow so fast through the grain bed and that rate is only slightly faster than what you can achieve by gravity alone. I typically pump fast enough that the grain bed will compact at least once during the mash and sometimes two or three times. It's no big deal. I simply stop, stir and resume pumping. I've found stirring to be very beneficial anyway, so it's not even an inconvenience. JMO and YMMV, blah, blah, blah...
 
Im busy designing a flow meter and display - I'll post the design here once its working. Ultimately it will control a motorized ball valve with settings for sparge, recirc, filling etc.
An option is to install a vacuum guage between the pump and MLT. That way you can pump as fast as possible without compaction. If you see the vacuum increasing you know to back-off a bit.
 
Im busy designing a flow meter and display - I'll post the design here once its working. Ultimately it will control a motorized ball valve with settings for sparge, recirc, filling etc.
An option is to install a vacuum guage between the pump and MLT. That way you can pump as fast as possible without compaction. If you see the vacuum increasing you know to back-off a bit.

I installed a vacuum guage on my RIMS pump just as you have described. This was a major improvement in the system.

4554827913_24d3fc4bee_z.jpg
 
This has worked very well for me. I've learned that the grain bed will inevitably compact when pumping at anything above the natural gravity flow rate. I generally run at about 1 psi or so. The compaction normally occurs very gradually so long as you go easy on the suction. Running the pump wide open will usually compact the grain bed very quickly and the flow comes to a screeching halt at that point. It only took me a few tries to find out where the red line was.
 
I use the blichmann inline flow meter and I run 1.5 gal/min exactly. On the last couple batches, I have gotten pretty poor mash efficiency (~73%) but I have been attributing that to a higher pH. I can't imagine my flow rate has any impact since I control the mash temp with a burner. Regardless, I have not experienced any off flavors from bed compaction at 1.5 gal/min (if that's what you are worried about)
 
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