More 12V pump possibilities

[Cathar]

Been seriously eyeing off one of these:

http://www.flojet.com/prodInfo/overv...000-124_ds.pdf

The 4405-501 model pump.

3.3GPM positive displacement pump (up to 40PSI or ~27m pressure head)
43W power draw
12VDC continuously rated motor

Just US$115 from www.depcopump.com. For us Aussies, that's amazingly cheap. Cheaper than an Eheim 1250 sells for here in the big brown land.

[Pelayo_Style]

arent the PD pumps loud ??

[Cathar]

These are meant to be quiet.

However, I just rang up the manufacturer and equired about the life-span as I couldn't find it stated anywhere in the on-line literature.

The diaphragm itself is only rated for about 500 hours (~3 weeks continual use) which makes the pump as good as useless.

(sigh)

Guess I'll keep on looking.

[Pelayo_Style]

LOL! that sucks, oh well.
HEY CATHER !! just wanted to say hi. I cant wait till the day i can have a Cascade block. Let me know when you can make some more.

[siavash_s_s]

i might make a pump since either me or a friend (fabricator) is getting a lathe and a mill soon, try out different methods and shapes for the turbines... im still thinking about a method using pistons and valves...

if you can try it out, most electic motors can be submerged so you could make one pretty safely with own dimensions, features etc..
just my 2cents

[Cathar]

I've always fancied attempting to get a lobe pump made up via plastic injection molding for the lobes. One could even use the same mold for both lobe rotors, and even after accounting for the draft required for the mold to eject, if they face opposite ways they will still line up just fine.

No need for the lobes to actually touch. They can clear each other by around 0.2mm or so. For a quad-lobe design, where each rotor is about 4cm in diameter x 2cm deep, giving a total external pumping chamber dimensions of around 9cm x 5cm, or no bigger than many centrifugal pumps, affix a shaft and same sized gears at each end of the rotor to ensure that they keep in sync, and do a standard mag-drive on one of the rotors to drive the pump, and you can have a relatively cheap to make high-pressure medium-flow pump.

Each revolution displaces about 7.5cc's. At a lazy (and quiet) 2000RPM, the pump would be pushing around 15LPM/4GPM. The clearances can be toyed with to balance the mag-drive's torque with flow "seepage" through the clearances to provide a correct balance with fluids of the viscosity of 0C cold water without causing the mag-drive to "slip". Aim it all to work for around a 25PSI peak pressure head at zero flow so people's heater-cores aren't put in danger.

Since it's a hobby pump, the pump mechanism casing would have to be cast in clear polycarbonate.

Oh well, I can dream!

[Huckleberry]

Check out this bad boy.

Tens of thousands are in service throughout the world. Some have been on the job for over three decades with only minor repairs in all this time!
Features:

1/6 hp motor

• 1/6 hp motor - quieter, smoother running
• Pump has one moving part
• Automatic shut off when fluid runs out (I'm sure we could mod this puppy for continuous operation)
• No creep controls
• Nylon dipped cabinet
• Quick Disconnect Hose standard
• In line stop cock
• pilot light shows when machine is operating

And if this isn't good enough, if your processor overheats and dies...

[lolito_fr]

"Porty-boy continues to keep pace with modern technology with superior components and materials. Pressures over 80 lbs. are no longer needed with today's improved chemicals. Mark V lowest pressure setting of 1-1/2 lbs. permits injection at minimum pressure and small flow rate.


[sorry ]

[Huckleberry]

I've heard that the low flow rates are preferred by Euro water-cooling systems.

I'm not so sure about the intended purpose for this machine.

Although on a serious note, I wonder how the pumping mechanisms would hold up under continuous use.

[killernoodle]

What about something like this?

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2452665790

Would that be loud?

[nexxo]

Possibly. What I would worry about more however, is that most bilge pumps are not continuously rated...

I said it once and I say it again: Johnson CM30P7-1. Magnetically sealed (so no leaks like its cheaper cousin discussed on this forum, the CO10P7-1) and brushless motor. Small. Quiet. 400 GPH. Continuously rated. Life span 10.000+ hours.

[fhorst]

Originally Posted by nexxo

Possibly. What I would worry about more however, is that most bilge pumps are not continuously rated...

I said it once and I say it again: Johnson CM30P7-1. Magnetically sealed (so no leaks like its cheaper cousin discussed on this forum, the CO10P7-1) and brushless motor. Small. Quiet. 400 GPH. Continuously rated. Life span 10.000+ hours.

Your'e right! but the prize..... it will cost me about 190 euro's....
For that prize I can have 2 MCP600, giving me the same performence, at a lower wattage.
(so I'm going to order 2, as soon as I've the news that the final fixed units are shiped)

[Cathar]

I managed to find the Johnson CM30P7-1 from www.depcopump.com for $149US.

Have been chatting to Dorian from Depco for a while now trying to source a good high pressure continuously rated 12V pump. We seem to have come up short time and again. The Johnson CM30P7-1 seems to be about the best one out there without getting into the $300+ range.

[Gooserider]

r I've always fancied attempting to get a lobe pump made up via plastic injection molding for the lobes. One could even use the same mold for both lobe rotors, and even after accounting for the draft required for the mold to eject, if they face opposite ways they will still line up just fine.

Interesting idea, I don't know how to make one, but your comment suggests a possible alternative. (Though not one I'm inclined to try...)

Do you know if anyone has tried using an automotive (or motorcycle) engine oil pump to drive their WC system? It would probably be a bear to adapt, and I don't know how it would wear, but it might give enough of an idea about the results to say whether or not further experimentation is worth it.

Problems that I see, which would have to be dealt with...

1. Sealing - the positive displacement oil pumps I've seen were all located in the oil sump, and didn't have any seals on the shafts. Presumably it would be necessary to either add seals or run the pump submerged in a res to avoid leakage problems. This leads to problem 2

2. Driving - presumably an electric motor would be needed. This leads to the problem of how to drive a pump that's in a res. Either the motor needs to be submersible / waterproof, or there needs to be a drive system that can get the powe from a dry motor to a wet pump. I don't think magnetic coupling would do it either. Perhaps it would be possible to hack a Danner style pump?

3. Wear - in an engine, the pump is running in oil (obviously ) and this keeps it lubricated. Would water be as effective in keeping the parts lubed? Particular concerns would be the friction between the sides of the lobes and the sides of the pump body. (sealing this area was one of the problems with rotary engines)

4. Metal compatibility - every pump of this sort I've seen has been either steel or Al, which might be an issue for a Cu/Brass based system.

Gooserider

[Cathar]

Originally Posted by Gooserider

Problems that I see, which would have to be dealt with...

1. Sealing - the positive displacement oil pumps I've seen were all located in the oil sump, and didn't have any seals on the shafts. Presumably it would be necessary to either add seals or run the pump submerged in a res to avoid leakage problems. This leads to problem 2

2. Driving - presumably an electric motor would be needed. This leads to the problem of how to drive a pump that's in a res. Either the motor needs to be submersible / waterproof, or there needs to be a drive system that can get the powe from a dry motor to a wet pump. I don't think magnetic coupling would do it either. Perhaps it would be possible to hack a Danner style pump?

3. Wear - in an engine, the pump is running in oil (obviously ) and this keeps it lubricated. Would water be as effective in keeping the parts lubed? Particular concerns would be the friction between the sides of the lobes and the sides of the pump body. (sealing this area was one of the problems with rotary engines)

4. Metal compatibility - every pump of this sort I've seen has been either steel or Al, which might be an issue for a Cu/Brass based system.

Gooserider

Thanks for some feedback.

1) I was thinking of something very similar to the way that current mag-drive pumps are sealed and shafted.

2) Again, using a mag-drive. The pump isn't a true PD pump, just one with a design that guarantees pretty high pressure. It would have a PQ curve not too different to that of a centrifugal pump, the difference here being the mechanism by wish the water is displaced. I believe the lobe pump mechanism would be more efficient than the centrifugal mechanism.

3) I was thinking that the lobes would be nylon, as well as nylon meshed gears that attached to the lobes to keep them in sync. Remember, the lobes aren't meant to actually touch in what I'm proposing, so the only real wear will be with the meshed sync gears.

4) The whole lot would be made of plastics, excepting the shafts, which will prob need to be stainless steel borne on ceramic bearings.

The other alternative would be a minature quimby screw pump.