Hyd Pump - What did I just buy?

[Heavy Metal]

Okay good news and bad news. Fixed the leak around shaft with more compression on the o-ring....but now I see a little seepage in the housing body which I think is just a design error...the raised lip on the plate that seats in the teflon ring pocket needs to be narrower and taller. Sealing the shaft was my main worry and looks like I might have that solved.

Will have to make a new plate this weekend and by then I might have a stronger motor to really test this thing out - the cheapo can motor just won't turn this pump once it gets up to pressure. If the new motor doesn't arrive by the weekend I might have to borrow the motor off my Leimbach pump.

Joe

[Stuff]

sweet!

[Heavy Metal]

Thought I'd post a little update on this. Have some good news and bad news on the Idex Micropump.

First the good news...no problem stopping the leaks in the shaft seal or housing. (Steve - I'll fill you in on that w/ PM later...ended up getting square o-rings for housing and quad rings for the shaft off McMaster so had to buy 50 pcs...will send you a handful to play with...they work good).

Now the bad news. I tried my Leimbach 12v motor to run this pump and it pulls a ton of current and doesn't have enough power to spin the pump to proper speed when it's running against the pressure relief - unless you feed it about 8 or 9 amps and even then it labors and never really spins up to a sustainable speed. I knew about this problem in previous posts but was hoping it was because I had the shaft too tight due to compressing the o-ring to seal the leak. So I did a serious of [poorly documented and unphotographed] experiments to see why the same motor that spins a Leimbach pump doesn't have the power to spin this pump. I will spare you the details and say that it ultimately led me back to review the specs for these pumps. Per L.G. Joe in the DIY Pump thread the Leimbach pump is a 350ml/min pump - not sure if that is max at full 10 bar (or is it 15?) but probably so. I didn't verify the 350 ml/min but sounds about right and Joe's numbers have always checked out before. So the Idex model 120 pump is spec'd for about 2000ml/min at 5.5 bar (80 p.s.i.) and the pumps they spec are shown to run 4000 RPM and pull 90 watts which would be 7.5 amps at 12v. That's a lot of current for a little motor.

Anyway...where am I going with all this babble...well I haven't completely drawn a conclusion yet...and I still think we can make this pump work...but my theroy right now is the Idex model 120 is trying to move about 6 times as much fluid as the Leimbach and these regular Johnson motors just weren't designed to generate that kind of power. Good news is these pumps have the extra capacity in a small package for the guys with big machines and big cylinders. Bad news is they are current hungry.

Next step is to run it geared down 3:1 or even more and see if the motor runs a comfortable speed and if it operates my test cylinders at the right rate. The pump seems to run 80 p.s.i. at pretty low RPMs so I am optimistic that lower RPM won't mean lower pressure...just lower volume and therefore ability to be driven by a 12v battery powered motor. Then I will insert the heavier spring I bought to modify the pressure relief to see if it runs closer to 10 bar, etc. etc.

Joe

[doodlebug]

Joe, you're on the right track with slowing it down for lower volume/amp's. I didn't have much luck with pump's in Vegas. Have to reload the computer, before I can post any picture's-Window's 7 Suck's! Mostly Window's Live!
Later, Neil#2 aka doodlebug.

[Finster]

Hi,

I hate to dig up old threads, but is there a final verdict on these pumps? Is it usable or not? Anyone find a solution? Thanks in advance.

[ihbuilder]

yes it could be usable I myself have not gotten to the testing stage . bear in mind , these are used pumps from some labatory set up . to buy a new 1 + replace the magnetic coupling is not worth it . New without the motor is aruond 300 usd . might just as well buy a "plug and play" set up from accross the pond .

[grumpygrady]

HERE IS A DRIVE FOR THAT PUMP

http://www.ebay.com/itm/NEW-Micropum...item4cfb99bc8d
and here is a link for the info on that series of pumps

http://www.micropump.com/support_doc...ical_Specs.pdf

[grumpygrady]

it says they are good for 300psi ?

[ihbuilder]

thats all well and good , but what happens when you get oil in the magnets . I've tried this with 2 of the smaller 1's I got as complete units .

[grumpygrady]

Originally Posted by ihbuilder

thats all well and good , but what happens when you get oil in the magnets . I've tried this with 2 of the smaller 1's I got as complete units .

ok i am confused
the one that was on ebay was a mag drive pump
it does not matter if you get oil on the magnets as they don't touch anything
in fact there is plastic between the two magnets

or are you talking about the one that was converted to shaft drive?

[grumpygrady]

the 120 series puts out 120 kpa which is 17 psi

http://www.csgnetwork.com/presskpapsicvt.html

[ihbuilder]

the reason for the mag coupling is to eliminate shaft seals I have 2 complete pump and motor set up with a mag drive . I tried 1 , as soon as I got oil in it it lost conection . They are not designed to pump oil with out removing the mag drive . then lies the ? if the poly pump gears will hold up in oil I might abandon this altogether do to what the pump was designed for ,deffinately not oil .

[Lil Giants]

So the magnetic connection will determine how much pressure it's capable of?

[ihbuilder]

Originally Posted by Lil Giants

So the magnetic connection will determine how much pressure it's capable of?

I'm not sure Joe I've talked about these with Freddy awhile back , we both agreed It just will not work for what we need . I guess in a sense it will these pumps are for some labatory/medical use not requiring a lot of press I think The 2 small pumps I have came with the motor and mag drive , not changing anything on them I can't get but a drip out of the outlet . for the kind of Pressure Joe and I get out of the bigger 1's they must have 1 heck of a magnet coupling . I didn't pay alot for the few I have ,but they require modification for our use . for what the cost new , your better of buying what we have available in the hobby already . I'll use what I have , cause I have them now , but in the future will just save for the Jung set up . I was really impressed with it for the few min. I took the controls of Ed's excavator . next is valves I just keep going back and forth on buying or make . I got to speend another grand on a collet chuck and collets for the lathe so I can make the plungers being that the big chucks I have now can't hold much smaller then 3/8" . tooling seems to win out these days though .

[ihbuilder]

well i finally got 1 to a useable state

smaller original pump as I got them



The 1st thing I did was cut the back of the housing down where ththe motor couples to the pump to give me more useable shaft without a slotin it for the goofy mag coupling . then made the sealing/coupling plate much like Joe did . then , using the bell that came with the motor to attach the motor much like the original . Instead of mag coupling I got the smallest bore lovejoy coupling from McM . The motor that came with it musta been gelded so , I had a 55T integy lathe motor and a RC4wth 4:1 reduction put it all together and ahlala insta pump at 15 bar pushing against the gage . bear in mind this is the smaller of the 2 type I have . it also has no relief valve .

[J-T]

Hi guys im in Australia and would like to know is
there some where i can purchase one of these (ebay etc)

I do know this has been asked , any help
would be great

Cheers Jay

[ihbuilder]

Originally Posted by J-T

Hi guys im in Australia and would like to know is
there some where i can purchase one of these (ebay etc)

I do know this has been asked , any help
would be great

Cheers Jay

YEA EBAY I just checked , there's not any on worth useing right now meaning cheap enough to make it worth while . you gotta keep your eye out for them .