Hpa Concept

[velocity3x]

If this idea has been suggested before, I apologize to the members and the originator.

This drawing is just a quick sketch to illustrate the concept.

In one day of light testing I can use 2 type "K" cylinders of gas ($70 per cyl). I've been looking ways to make HPA inexpensively in large volume in a relatively short time frame. Type "K" cylinders (aka 200cf) normally contain 2500psi and ideal for my purposes. The problem I found with high pressure compressors is that they are slow to produce gas in large volume and they are expensive. A high pressure washer is a fairly common in the home garage and they produce a large volume of incompressible liquid at high pressure.

The basic idea is this:
The pressure washer pumps incompressible liquid into the first tank. The air in the first tank is displaced and forced into the second (holding) tank at higher pressure. When desired pressure has been achieved in the holding tank, the first tank would be drained and the process repeated for the next fill. Essentially, one would be wasting a few gallons of water to gain many cubic feet of HPA.

Practical or not? Thoughts?

[Gippeto]

The idea pops up now and again.

Consider for a moment...Let's make the assumption that you fill the "80" from your shop compressor, and that you've a decent one so it fills to 150psi.

Making a minor attempt (otherwise known as a wag) to account for some of the losses in the system, you'll end up compressing that 150psi 17-18 times (compression ratio) to end up at 2500psi.

It'll obviously take several (understatement) fills of the small cylinder to achieve 2500psi in the K cylinder. It won't be quick or easy, but in the end, it is "do-able".

Have you looked into pressure boosters? A couple in series (or a two stage booster) could be the answer, and as you know someone with skills, and machine tools, they could be sized to provide the fill times you want.

[velocity3x]

Have you looked into pressure boosters? A couple in series (or a two stage booster) could be the answer.

I've done some looking but, other than scuba compressor$$$ I've not found anything (or combination of things) capable of filling a type "K" to 2500psi in a reasonable time

[POLAND_SPUD]

yeah, what gippetto has said.. or try to build this http://www.spudfiles.com/forums/viewtop ... tml#281822

since you have access to machining and some $ to spare you could be the first person to build one here

[velocity3x]

Poland,
I've considered designing / building a 2 cylinder, long stroke, high pressure pump with water cooled jackets and driving it with a 5hp 240v motor. I'm beginning to think it's the best solution and I'd rather put the $ in my own design rather than a commercially available pump. I guess I'm just looking for an easy solution as I'm just damn tired of designing/machining, designing/machining! Can't anything ever be easy fix?

[POLAND_SPUD]

well you can also design an air powered compressor, which is basically almost exactly like a pressure booster...

you'd need a large bore air cylinder, stirrup pump and one or two DCVs

such a design would be a little bit simpler than the one you planned but it requires a shop compressor to operate

[Crna Legija]

how about a small petrol engine converted do you think it could make that kind of pressure

and why cant you use the pressure washer to pump air directly?

[POLAND_SPUD]

@-_-
I've seen car engines modded into air compressors but due to the large diameter of the pistons (and even larger area surface) I don't think teh idea is feasible for high pressures

well unless you can find address that issue... that would require either using some sort of insert that can be put into the cylinder and machining new, smaller pistons or modding a smaller engine