Easy 200psi... er make that 400psi stirrup pump

[Gippeto]

I was thinking about a pump design the other day. Nothing revolutionary, just something that could be built by the average spudder with average tools. Something with (maybe) better efficiency than average.

Since I could not stop thinking about it, I went ahead and built it. Here it is, ready for comment.

Only power tool used: drill press

Cost to build: About 20.00 for the pump and check valve. Another 10.00 for the manifold. Gage and valve belong to my work.

Performance: 4 strokes brings the gage over 200 psi.

Thanks for looking, let me know what you think.

Edit: Added piston pic
The copper tube is 3/4" type M
Dead space approx. 0.1cu.in.
Mechanical compression ratio 103:1

Edit: Finished testing pump. Pressured to ~408psi. Held for 3 hours, then re-checked clearance at pump handle. No change. Uploading pic.

[Maniac]

oh goody may you explain the o ring setup in it. and what size copper that is.

[pizlo]

Please explain, and how bis is the chamber you're brining to 200 PSI?

[Gippeto]

Added poll.

Maniac,

On the intake (up) stroke, the o-ring is pushed against the bottom washer. Air enters at the gap above the o-ring and follows two passages (filed into the threaded rod) past the nut.

On the compression (down) stroke, air pressure pushes the o-ring against the upper washer and the cylinder wall, forming a seal.

As the air is compressed, the check valve reaches a point (cracking pressure) where it opens and lets the air into the manifold (and a spudgun maybe?). When the manifold pressure and spring pressure equal the cylinder pressure, the check valve seals, allowing another intake stroke.

Pizlo,

I hope I explained what you wanted, you were not very specific. I installed the pump on a manifold with a tee, gage, and venting valve. This was in the pictures. It's probably about 2 cu.in.?

[VH_man]

The o-ring thing looks complex but also easy to contsruct.

and is that epoxy i see? JSR is going to be proud.

[Novacastrian]

That is one sexy piston, great work mate.

[jackssmirkingrevenge]

and is that epoxy i see? JSR is going to be proud.

It was the first thing to catch my eye, looking VERY good

Those of you with copper launchers, please take note

[MrCrowley]

If approved by the mods, is there a need for a how to on this pump and check valve

You don't need to approve, just go ahead and do it

And no, I don't think you can change the picture order without removing them and then reuploading them.

[elitesniper]

that very neat, good job on the pump

[Brian the brain]

where did you get that checkvalve?

[Gippeto]

Thanks, it was a fun little project.

Nova, we need to find you a lady friend! But thanks all the same.


Pictorial on photobucket. Check valve and piston.

http://s245.photobucket.com/albums/gg76 ... k%20valve/


I'll sit down and flush out the instructions this weekend.

Comments with details anyone would like clarified might be of help.

[jackssmirkingrevenge]

I'll sit down and flush out the instructions this weekend.

Good lord, we have another one! scroll down

[Mitchza89]

She's a little beauty mate, really well done on this one. That reminds me, I better post my homemade pump I made a few weeks a go

Although you've gotten to 200psi, what's the psi max your after?

Well done again mate,

Mitch.

[bluerussetboy]

so your piston is basically a copy of the piston found in shock pumps, made of nuts and bolts, not a piece of aluminum nicely machined?

what do you think your check valve is rated for max? 200 psi? 300 psi? 400 psi?
if it can't go over 250 psi then i might as well just buy a brass 3/4" check valve from lowe's or home depot or any plumbing supply.

200 psi in 4 pumps in a closed tee doesn't really tell us much other than your pump can fill a small tee and hold 200 psi.
if i cap my fox hp pump it takes less than 5 strokes to max out at 300 psi.
i would prefer to know how many strokes it takes to fill a chamber that is 24" long of 3/4"(.785) copper or 11.616 cu. in. of volume to 200 psi. this would be more a "real world" measurement.

[Gippeto]

Er, um ok... I'll add more detail to the instructions.

This was not really so much a case of max psi. I have calculated that 300 psi will take a force of 154.5 pounds to achieve. If someone needs more pressure, they can either work harder or use a smaller diameter tube/piston.

The premise for this pump was to make something which a lot of people would have the tools to replicate. If I were to fire up the lathe, then sure I could make a pump with virtually 0 dead space, and a check valve good to whatever pressure I wanted. But there would be only a few here that could reproduce it.
I believe that the check valve will easily go past 250psi, but no, I have not calculated a max rating. Even if I were to crunch the numbers, different manufacturing techniques (silver soldering ,sweating, epoxying) would alter the properties of the material sufficiently to render the result useless.
The primary reason for building a check valve, was to reduce the amount of dead space in the pump. With your wog check valve from lowes, you have a lot of dead space (comparatively). This would require a larger swept volume to achieve a similar pressure increase.
And Finally, in an ideal world, your chamber would take 14 strokes to fill to 200psi. So in a real world, lets say less than 20.
It may not be the solution for everyone, but it should suffice for many.