Brewing Clamper
Well-Known Member
So how do you guys control the flow of wort in a RIMS? Do you restrict the flow with a valve or control the speed of the pump with something like a dimmer switch or a PWM? Thanks!
RIMS flow control
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I restrict the flow coming out of the MLT with a ball valve.
squirrelly
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Are you referring to the recirculating, the sparge water, or the run off? For the recirculating I just run everything wide open and let it go full bore for the duration of the mash. For the sparge I open my mashtun ball valve 1/4, the sparge arm 1/4 and let the float switch control the water level. For the run off into the boil kettle I keep my boil kettle valve open 1/4 and sparge arm open 1/4 again letting the float switch control the water level in the mashtun. I try to keep my run off at 1 gallon per 5 minutes and keep the sparge water 1" above the grain bed.
scottland
Well-Known Member
You never want to restrict flow to your pump. (I'm assuming your pump is immediately downstream of your MLT.)
Put a ball valve on the outlet of your pump, restrict the flow there. It's relatively easy to control.
HearthstoneBrewery
Well-Known Member
I use a brass gate valve from Home Depot. It gives me finer control than a 1/4 turn ball valve.
Not sure I agree, the pump never runs dry and it's magnetic driven. Besides when using silicone tubing it is suggested you don't want to restrict flow on the pressure side. The tubing isn't rated for any real type of psi. I only restrict enough to stop the grain bed from compacting too much from the suction created by the pump.
Silicone Tubing 1/2" ID x 3/4" OD
10 psi max pressure - DO NOT RESTRICT ON THE OUTPUT SIDE OR YOU WILL POP THE TUBING
Wait... Wait... You do not restrict the flow "after the pump" you restrict the flow with an output valve ON the pump. NO tubing is then subjected to pressures.
The March pumps are less than 10 PSI. You can restrict the output side without a problem. You do not want to restrict the input side.
I do the same thing as most people have posted, I adjust the flow with a ball valve on the out-side of the pump.
shortyjacobs
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p-j said:
+ 1
squirrelly
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I'm curious why we would not want to restrict the flow of liquid going into the pump. I ask because when I bought the system from more beer the metal shop tech who gave the how to didn't say anything about that. In fact he was the one who advised keeping a valve 1/4 the way open to ensure the pump kept its prime. I've been on the more beer forums for quite a while, and I have never stumbled across this in the "sculptures" section.
I am not the most mechanically inclined of people, so a dumbed down explanation would be greatly appreciated. Am I putting my pumps at risk?
I am not the most mechanically inclined of people, so a dumbed down explanation would be greatly appreciated. Am I putting my pumps at risk?
scottland
Well-Known Member
The pumps cavitate rather easily, you'll destroy the pump head if it runs dry for too long. Email March if you don't believe me
Oh wait.... https://www.homebrewtalk.com/f11/questions-about-march-pumps-answered-factory-210199/
See posts 17 and 20 from Walter at March pumps.
Oh wait.... https://www.homebrewtalk.com/f11/questions-about-march-pumps-answered-factory-210199/
See posts 17 and 20 from Walter at March pumps.
shortyjacobs
Well-Known Member
If you restrict the flow of liquid going INTO the pump, you can cause lowered pressure inside the pump head, (basically, suction). This increases the risk of cavitation in the pump head. Basically, as the impeller whirls around, it creates an area of low pressure behind each vane. If you create a lower pressure system inside the whole pump cavity by restricting the pump inlet, you have a problem. Lower pressure is created because the pump is trying it's damndest to push fluid OUT. As it pushes fluid OUT faster than the fluid can come in because you restricted the inlet, the pressure inside the pump head drops. As the pressure inside the pump head drops, the lower pressure zone right behind each vane of the impeller drops even LOWER, to the point where the liquid can actually boil, even if it's not at 212F. This flash boiling of liquid inside the pump in those low pressure zones is called cavitation. (Cavitation can even happen at cold temps.....it's a major cause of damage to high performance propellers on ships and submarines). The cavitation-created steam bubbles can damage the pump housing, (unlikely), and cause you to lose prime, (likely).
By restricting the OUTLET, you actually increase the pressure inside the pump head, which has no ill effects, (it can't go up much, as the impeller will "slip" on it's magnetic drive before bad things happen). Yes, having your system go "pump -> silicone tubing -> valve" and closing that valve could cause your tubing to pop off. However, going "tubing -> pump -> valve -> tubing", (attach the valve directly to the pump), will cause no problems.
By restricting the OUTLET, you actually increase the pressure inside the pump head, which has no ill effects, (it can't go up much, as the impeller will "slip" on it's magnetic drive before bad things happen). Yes, having your system go "pump -> silicone tubing -> valve" and closing that valve could cause your tubing to pop off. However, going "tubing -> pump -> valve -> tubing", (attach the valve directly to the pump), will cause no problems.
shortyjacobs
Well-Known Member
Interesting, in post 21 he even says running it with a restricted inlet can cause wear on the thrust washer and potentially bind/stop the impeller.
Just having trouble understanding how turning the ball vavle a 1/4 turn is any worse than someone using 3/8 tubing from their false bottom and then running 1/2 tubing to pump. Or for that matter the suction caused by the grains compacting against the false bottom. If you are running a RIMS without a grant or something similar, I got news for ya. Your restricting the flow to the pump, wheather you want to are not. Now, maybe a March pump isn't the best option for a RIMS system...I'll give you that.
OneHoppyGuy
Well-Known Member
Inlet side... Walter said not to restrict the inlet side. You restrict the outlet side.
Think about siphoning: to reduce the flow, you pinch the end where the water is coming out, if you pinch the other end it won't be able to siphon properly.
March pumps work excellent for RIMS.
Think about siphoning: to reduce the flow, you pinch the end where the water is coming out, if you pinch the other end it won't be able to siphon properly.
March pumps work excellent for RIMS.
OP
OP
Brewing Clamper
Well-Known Member
Wow, this is great info guys! Thanks!
I agree that the March pump works great for my RIMS and I don't regret for a second using it. But if you follow the blanket statement that there can be no restrictions pre-pump, then it "shouldn't" work for a RIMS. But still it does....Oh well, life goes on. Happy Brewing!!
