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An idea to double or triple pressure.

Posted: Thu Apr 01, 2010 10:34 am
by boyntonstu
You have a 1" diameter steel pump 12 " high vertical in a 2 ton hydraulic press connected to you chamber below. Check valve, cut off valve etc.

Fill the pump/chamber to 600 psi with you a/c compressor.

(see my post on pressure assisted a/c compressor)


Use the hydraulic press to push the piston down to the bottom with 4,000 pounds of force

These pumps are under $20 at Harbor Freight..

Depending upon the volumes and diameters involved, your chamber will be filled at much higher pressure than 600 psi.

Posted: Thu Apr 01, 2010 11:16 am
by SEAKING9006
Hmm. It's an interesting idea, and may have applications of those attempting super high pressure guns or high mix hybrids. The main issue is getting a proper seal in your steel pump tube.

Posted: Thu Apr 01, 2010 6:26 pm
by daberno123
Good idea, but honestly the hydraulic press you're talking about will probably break. I've heard a lot of stories on a few machinist forums about the frames bending on the Harbor Freight version.

However, with a properly built hydraulic press it would definitely be doable...just not as cheap as you're thinking. :wink:

Posted: Thu Apr 01, 2010 9:10 pm
by ramses
I think he's talking about a bottle jack, and they won't bend unless they were practically engineered to do so. some apparently go up to 10 or 20 tonnes. You might consider an air powered bottle jack. They cost a little more, but they will move much more easily. You could also somehow motorize the bottle jack. In either case, you need something to trip the auto-return of the jack at the end of the stroke to have complete automation.

If you get a more powerful jack, you should increase the diameter of your pump tube.

Posted: Thu Apr 01, 2010 9:55 pm
by boyntonstu
There only needs to be a single stroke to further compress the 600 psi within the pump/chamber.

The return stroke would be done by pressurizing for the next fill.

Perhaps 2 bottle jacks connected piston to piston would work.

The first, as the air pump, the second to apply the hydraulic force.

A frame needs to be fabricated to create the push 'from' and the push 'to' positions. My guess is that a 36" length of I beam and a welded or bolted platforms would be able to withstand 10,000 pounds of force.

Posted: Fri Apr 02, 2010 9:12 am
by ramses
for the return, I meant that you need to open the bleed valve on the jack. Otherwise, it won't retract until something important breaks.

The I beam could work. One would have to do the math. the unused channel would have the walls in compression to resist the bending load that arises from having the jacks not inside the center "web".

Posted: Fri Apr 02, 2010 9:59 am
by boyntonstu
ramses wrote:for the return, I meant that you need to open the bleed valve on the jack. Otherwise, it won't retract until something important breaks.

The I beam could work. One would have to do the math. the unused channel would have the walls in compression to resist the bending load that arises from having the jacks not inside the center "web".
Yes, you must open the bleed for the cylinder ram to retract.

If you used 2 I beams spaced apart just wider than the jacks and welded on 1/2" steel end caps it would be quite strong.

An easier alternative would be to use a pair of 2" steel pipe nipples 36" long, 4 floor flanges, and 5/16" bolts and nuts to hold 1/2" steel end plates.

I imagine that may be strong enough and easily home built.

Posted: Fri Apr 02, 2010 10:03 am
by POLAND_SPUD
@boyntonstu
you might as well build an air powered compressor... well basically that could be a pressure booster too

Posted: Fri Apr 02, 2010 11:18 am
by inonickname
daberno123 wrote:Good idea, but honestly the hydraulic press you're talking about will probably break. I've heard a lot of stories on a few machinist forums about the frames bending on the Harbor Freight version.

However, with a properly built hydraulic press it would definitely be doable...just not as cheap as you're thinking. :wink:
Hell...I've seen people bend them while pressing black powder rockets..I'll try find a picture.

Well..couldn't find it. But there's a guy on APC that bent his HF press while ramming a very large rocket.

With the press in question, not a great idea. Also remember that if something goes wrong, there's a lot of energy in there.