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View Full Version : Safety cutout idea, for watercoolers.


RoadWarrior
11-26-01, 12:28 AM
Hi guys,

I'm fairly new to the water cooling game, though have followed developments interestedly online for several years.

Anyway, as I have just made my mind up to take the plunge and build my own, I started pondering the consequences of pump failure. And they ain't pretty. So here's an idea I have had for a safety cutout, that should shut down the system to stop your CPU frying. It is not aimed at preserving data, after all in about five seconds longer you were going to lose it all anyway AND your CPU.

This is workable as a bit of a combo device, flowmeter and CPU saver, it won't work so well for you guys that have your pumps wired into the system power, but for anyone switching thier pumps seperately, I think it's a goer.

What I propose is a ball bearing, in a wider perspex tube, mounted vertically, say on the side or front of your case. with a restriction at the bottom, so it don't fall down the inlet and at the top to stop ot blocking the outlet, although water or coolant should have free passage around it in these positions. The inlet is at the bottom, the outlet at the top. If you arrange the bore of the tube and the size of the bearing nicely, it will be supported by the water flow some distance up the tube. If there isn't enough room around it it will shoot to the top, if there is too much it will barely lift off, I guess you want to aim for getting it to hover about midway. You will need to change these parameters if you use a higher or lower viscosity coolant, and flow indication differences between viscocities will not be comparable.

Now, you can see the ball bearing bobbing about at around your normal flow mark, any higher, you improved the flow of the system, any lower, you know you've got a blockage building, or a pipe half kinked. On the bottom, you've got NO FLOW!!!

Now, if we put a couple of wires/bars through at the bottom, we can have an electrical contact made when there is no flow. What can we connect this to?

I would suggest connecting one side to a splice off the PSU's power good line, and the other side to ground. Thus your PSU won't supply power when there is no flow. Result, no nasty accidents due to forgetting to fire up the pump first, and instant power off in the case of pump failure.
You will of course need to limit electrolytic conduction in your coolant to get a good signal out of this contact, and you should take measures to prevent scale in your system, otherwise, your failsafe may not work when you most need it to.

Ideas, comments, flames.????

If no-one did this yet, I hereby name it the RoadWarrior flowguard.

Road Warrior

RoadWarrior
11-26-01, 12:37 AM
Dunno if this ascii is gonna work....
_____
| ___ > out
| |
/ \
| |
| |
| |
| |
| |
| | < mark normal flow.
| |
| |
| |
| |
| |
| |
| O | < bearing
|# #| < contacts
\ /
| |__
|____ < in

RoadWarrior
11-26-01, 12:40 AM
great, courier with *proportional* spacing, who'd 've thought [sigh] Maybe it's just this NS 6.2

Drw714
11-26-01, 12:44 AM
Do you run an AMD?

I have a Tbird 1.2...
How warm/fast do you think it's safe to run?

Thnx for any help!!

RoadWarrior
11-26-01, 12:53 AM
Oh, a mod to it for people who don't want electrics inside thier system, or use tapwater in evap coolers and can expect some scaling....

Take the slug out of a magnetic marble to use as the "float" or whatever you wanna call it, and put a reed switch at the bottom.

also if you wanted to hide this unit away I guess you could have multiple reed switches all the way up the flow column and connect them to a bargraph LED on the front of the case.

another thought, fit it right after the CPU outlet, fit it in the line in, and you could be measuring just how quickly you are filling your case up with coolant, in the out line, you know that that's coolant actually going through your block!

regards,

Road Warrior

RoadWarrior
11-26-01, 12:57 AM
Sorry DRW not got my sticky paws on a real CPU yet, gonna be testing this on K6-2s, hopefully about January I'll get my Athlon. Lotsa people here for that kind of advice though. From what I've read, they get flakey over about 50c, so keeping them below that is optimum, even though they don't actually burn up until over 90c or so.

Drw714
11-26-01, 01:04 AM
Thnx for the help Road!

I've got it running pretty sweet I think!
Seems stable and running around 49c
under sever load (Sandra)....

I just bought it this weekend
with an Abit Kg7 ($270 Not bad w/
128m of DDR Ram)

I've got it running at 1350

9x Multi
150 bus

Thanks again for your help!!
I don't think I'll try to tweek
it anymore than that then...
:D

ButcherUK
11-26-01, 10:17 AM
Sounds a bit like something I designed for checking coolant levels, basically have two contacts at the min level, water completes the circuit, when the water drops below they go into free air and the circuit breaks, this switches on a light / buzzer / solenoid for tap / etc. :)
Very simple construction if anyone is interested I'll post a schematic.