PCP pump...

[kiwi]

Hi..
With all the talk about pumps/compresser for PCPs...
Well I tought I should make one..had a idea for a while
Try to make it simple to build "well as simple as it can be"
needs very few pumps to top up or fill a avarage size gun
& next to NO efort required...

trying to make something that can be built at home with
a small home lathe & a few clues...

So I have got most of what I need to make a start..

Power is from a 20ton bottle jack...
the ram will be 53mm bore X 170mm stroke
giveing a volume of 345cc..& will be filled from a compresser
to 120psi giving a filled volume of 3 letres. @ 120 psi..
compressed 204 times will give a out put volume
 of 145cc @ 3000psi per stroke....

the force required works something like this....
at 3000psi there will be 12,000lbs of pressure on the piston head
the jack at 20 ton =20,000kgs = 44.000 lbs force..so theres
32.000 lbs of force above what is required to do the job..

how it fits togeather.....
there will be a flange that fits under the top seal retaining nut of
the jack.& another flange welded to the bottom of the ram with
a spacer ring and 5 10m though bolts between the 2 flanges
holding everything togeather....The top of the ram will have a head welded on
with porting for the inlet from the compresser with a high pressure hyd ball vave...
 The outlet will have the fill line to the gun useing the non return valve in the gun
bleed off will be from the inlet valve...disconect the compresser line & bleed off with
the ball valve...

Piston...
will be  free floating & sit on the top of the ram shaft...Seal will be cup style machined
from UTR nylon..that is a self lubeing nylon...

Ram bore...
has to be smooth no hatching marks....with up to 3000psi forceing the cup seal
against the bore any hatch marks will be like draging the seal down a file...
The bore is honed & polished smooth "1000 grit barrel hone"
boreing the ram is the only bit that is unable to be done on a small home lathe..
even at work it was a drama...our biggest boreing bar that would fit in kept
chattering over that length 250mm..but I finaly got a honeable surface...

anyways..i will try and keep this tread going with a blow by blow account..
So if anyone wants to build one or swipe a few ideas...

Pete

[Gene_SC]

Send me the plans Paul...:) Yes please do keep us up to date on your progress. Where there is a will there is a way...:)Thanks...

[fisherdude]

That's a great plan. I have been tinking of making a similar one from a hydraulic cylinder.

[kiwi]

All done apart from the threads...
It is steped 20mm to fit inside the ram tube
so the weld is not near the working section
of the ram...So theres no chance of destorting
or getting any weld blow though on the surface
that the piston seal runs on....as that could/would
stuff the seals top lip or cause a sudden 3000psi leak ...

Pete

[kiwi]

hi..
its all but ready to go togeather...
got the monting flanges done...
piston & seal...seal has a 2* tapper
on it with the top .5mm larger than
the bore bottom is size for size...
there will be a filler plug inside the piston
to desplace volume & hold the seal on..


pete

[JimH]

Is it your intent to simply attache a hose directly to the gun and pump her up? or fill a tank?

[kiwi]

JimH - 4/4/2010  3:00 PM

Is it your intent to simply attache a hose directly to the gun and pump her up?  or fill a tank?

to the gun....815 stroke cycles to fill a 80cf tank from empty...250 odd for a 1000psi top up...

Eg....marauder has a 215cc tube so if yer shoot it to half fulj it will need a 107cc top up
thats 6 or 7 stroke cycle...beats 150 or more from a PCP pump & yer won't rase yer heart beat...

The idea is to transfur the pump on to a air over hydrulic jack so no pumpimg a handle..
just push a button...But I will check it all works as I hope with a cheap jack first..

Pete

[kiwi]

Hi..
Now comes the tricky bits...
non return valves & bleed valve..

the centre hole is the non-return valve to stop
the air retuning back to the ram..The hole next
to it is for the bleed screw the small hole above
the out let coupling is where the air bleeds out...

Pete

[jake]

great idea! i can see this going somewhere....

[kiwi]

dam these valves are a pain in the !...
got the last one done...this is the non-return
for the inlet  will stop the pump pressure returning back
to the compresser..
Ps..its got the correct size O-ring on it now...4mm X 1mm

[Leadbetter]

I like the way you are thinking!!!  The funny thing is I build drag racing automatic transmissions and I am always tinkering and machining parts for the trannys .After I bought my first pcp I thought man I could make my own pcp pump out of a hydrolic cylinder "long stroke" and an air cylider  I have an entire machine shop to tinker in to perfect it .I think you are well on your way man good job !!!!

[fatback]

keep up the good work Pete... you always come up with something cool wish I had access to a shop...lol

[ray1377]

This is very interesting.
I'll be watching this one as it progresses.
Way to go pete.
Ray

[rocker1]

i spent almost a year in nz, i met my wife there about 7 years ago. the country is very beautiful i mean breathtaking. i found the people there very ingenius  they can fix more with less i have no doubt what petes doing will work.  only thing there i had trouble with was driving on the wrong side of the road going the wrong way lol!!! good luck pete  david

[kp4att]

THAT IS AN INTERESTING PROJECT.  KEEP GOING.


/GERALD