Flow rate control to 12V solar pumps

[grunter]

I wanted to slowly turn on the beige beauties for mash re-circulation to stop it sticking etc

Anyone done this before ?

not sure if its a variable resistor or Pulse with mod i need?

found this one amazonk:

https://www.amazon.co.uk/12V-40V-Motor- ... B007TH4EN6

[Kev888]

I used variable voltage, seemed to work fairly well unless you need 'really' slow flow rates (the motor's electronics don't like the voltage being 'too' low). Apparently PWM works as well, though it wasn't great with some cheap/nasty chinese PWM modules I once tried; I'm assuming that was the modules rather than the principle but can't say from personal experience. Or you can use a valve on the outlet to manually restrict the flow.

[aamcle]

I've used a cheap PWM module from evilbay with success.


aamcle

[donchiquon]

A ball valve screwed onto the output of the pump will do the job simply. As far as I understand the magnetic coupled pumps are very happy to be throttled on the output.


Ian

[Fil]

i use variable voltage too, an ebay 2a tattoo gun PSU provides a cheap and tidy dial up and down controller with an easy to read gauge or meter at a glance. i splurged almost £20 on one with 2x output sockets selected with a switch and a shiny Stainless steel box but they should be available at a less than that in powder coated mild steel or plastic, the only mod needed was to fit a permanent short/connection of the footswitch socket and a 1/4" mono jack plug to the pump power lead.. and they can supply upto 18v..

to achieve the slowest flow however its a case of dialing up and then back down, trying to start slow by winding up the power/voltage results in a faster initial start flow which can then be dialed back a bit, i would guestimate the control to be roughly from 45%-100% (or perhaps 150% if dialed all the way upto 18v tho thats probably not a good idea for any length of time/at all.. i have only experienced it in error, and its not a pump killer if addressed promptly.

added bonus blutack a pc fan to the top with a couple of rare earth magnets glued to the hub and you have a magnetic stirbar solution for your yeast starters too

[Dave S]

A ball valve screwed onto the output of the pump will do the job simply. As far as I understand the magnetic coupled pumps are very happy to be throttled on the output.


Ian

But Solar pumps are not magnetically coupled and they do not recommend controlling the flow by throttling.

[donchiquon]

But Solar pumps are not magnetically coupled and they do not recommend controlling the flow by throttling.

I’d understood from the Solarprojects site that you could use a variable voltage or a gate valve with them

http://shop.solarproject.co.uk/catalog/ ... ucts_id=10



Ian

[aamcle]

A valve on the exit wont do much harm as they are centrifugal pumps, the effect is the same as running them at their maximum head (lift) it would be working harder but that's all.

The likes of the little brown pump just spins if it's blocked off however a piston (positive displacement) would stall and probably be damaged.


ATB aamcle

[Dave S]

But Solar pumps are not magnetically coupled and they do not recommend controlling the flow by throttling.

I’d understood from the Solarprojects site that you could use a variable voltage or a gate valve with them

http://shop.solarproject.co.uk/catalog/ ... ucts_id=10



Ian

Yes, you're right, I hadn't spotted that. I thought they only recommended variable voltage.

[Kev888]

You are correct that they aren't truly magnetically coupled though; the whole shaft and magnet are flooded instead.

In theory the brushless motor can better handle restriction (whereas a brushed type would begin to draw heavy current). Though a few of mine in succession failed after working hard on hot days, so I'm not confident they are truly happy under very heavy mechanical/flow restriction. Similar resistance can occur if tiny particles get in the narrow gap around the motor's shaft, too.

[Dave S]

You are correct that they aren't truly magnetically coupled though; the whole shaft and magnet are flooded instead.

In theory the brushless motor can better handle restriction (whereas a brushed type would begin to draw heavy current). Though a few of mine in succession failed after working hard on hot days, so I'm not confident they are truly happy under very heavy mechanical/flow restriction. Similar resistance can occur if tiny particles get in the narrow gap around the motor's shaft, too.

Yes, they don't have a very good press for pumping wort or other particulate fluids. I keep mine for pumping water only.

[Eric]

You are correct that they aren't truly magnetically coupled though; the whole shaft and magnet are flooded instead.

In theory the brushless motor can better handle restriction (whereas a brushed type would begin to draw heavy current). Though a few of mine in succession failed after working hard on hot days, so I'm not confident they are truly happy under very heavy mechanical/flow restriction. Similar resistance can occur if tiny particles get in the narrow gap around the motor's shaft, too.

Yes, they don't have a very good press for pumping wort or other particulate fluids. I keep mine for pumping water only.

I've had my fair share of problems with these pumps, but have had a better run of late.

They are powered by a brushless motor, the rotor an encapsulated magnet which the pumped liquid surrounds to act as a lubricant/coolant. They work perfectly well with clean water and flow can be succesfully controlled by the combined actions of a ball valve for coarse adjustment and a variable pulse width modulated power suppy for incremental control. They will stall with a too low power supply and the system should be purged of air or steam.

When used with beer or wort they need to be regularly stripped and cleaned and can jam if pieces of grain become lodged to become unreliable. I use them for recycling wort, but always have a serviced spare to hand.