Re: Water cutter

The idea may work but here is how I think your design will work.
The supply pressure enters the inlet.
The plunger moves to the high pressure side.
The plunger uncovers the exhaust ports but some of the HP water opened the
ballcheck valve as it was moving.
Once the plunger moves to the position where the exhaust port is opened the
pressure will be somewhat less than on the HP side. the pressure will be
greater on this side plus the spring thus moving the piston back until the
exhaust ports are sealed by the piston/plunger body. At this point the
pressure is greater on the supply side and then opens the ballcheck valve
and moves the piston towards the HP side repeating the cycle.
The formula that you are looking for is F=P*A
F= Force
P= Pressure
A= Area

By knowing the pressure on both sides of the piston you will see whcih way
the piston must move. A differential piston may work better. Hmmmmmmm!


There seems to be something missing and I'll have to think about what it is.

-----Original Message-----
From: Arne Chr. Jorgensen <instel@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Wednesday, August 11, 1999 4:10 AM
Subject: [CAD_CAM_EDM_DRO] Water cutter

>From: "Arne Chr. Jorgensen" <instel@...>
>
>Hi,
>
>Okay, - several has come with input to this subject, and I am
>just going to say something about it.
>
>From Dan: - you could probably cut basla wood with 2000-3000psi
>All others came with valuable comments and info, - some of it I
>have not check out yet. My idea is to use the "impulse" effect,
>and the way I think of it, is like a what happens in an inductor.
>
>The describing equation for an inductor, is
>
>U= L di/dt, and the power is E=1/2 Li^2
>
> Fluid inertia is,
>
>P=I dQ/dt, and the power is E=1/2 I Q^2
>
>( P= pressure, I = fluid inertance, Q is volume flow )
>
>( If anyone think I have any math skills, - I don't :-)
>
>The principle is *very old* , they used this in old monostries to
>have a fountain, and the locations were often on high places with no
>water. They used this system, and the river that supplied the water,
>could be a 100 meters below.
>
>As in my "STIR CRAZY" note - where I had to many drinks, I
>suggested to test Xfig in Linux, to pass ideas. I made a simple
>drawing of what I had in mind, and put it in the drop box, at
>http://www.metalworking.com The drawing is: pr_fig.gif
>
>Take a look at it, and come with comments !
>
>If we could just double the pressure, - we would be able to cut
>balsa, styrofoam, and stuff.
>
>Here is some of the named parts:
>
>1 - inlet pressure from pressure washer
>2 - valve
>3 - exhaust ports
>4 - plunger
>5 - spring
>6 - nozzle.
>
>The inlet pressure will press water into the pressure chamber, but
>the face of the plunger is designed so that it will push the whole
>plunger in. After it has moved a bit, the exhaust ports will be
>open. This is importent, as you want the pressure washer to supply
>a constant volume of water, and not open the "over" pressure valve
>on the pump. ( The exhaust water, can be collected in such a way,
>that it will not make a lot of water spill at the cutting head. )
>
>Because the area is smaller in the high pressure side, - you will
>have an increase in pressure, but at a smaller flow rate. The unit
>will genereate pulses, but there is many ways to make it more like a
>steady flow. You also may need an "air chamber" - but I am not
>sure.
>
>Here is place for a lot of improvements. You could make a unit as a
>push-pull design, add more stages, or put them in paralell. Here I
>just wanted to show a very simple design, - and hear your comments.
>
>The idea, is that this should oscillate, and in principle, it would
>be like your ignition coil in your car, bringing the 12V up to
>20.000volt. ( I know about the secondary winding, - but you get
>1000V or so on the primary - and that is exactly the same principle
>)
>
>I don't have the tools to make this, - yet. So if anyone wants to
>experiment - do so !
>
>But, I would suggest to just use some simple pipes/parts, use air
>as the fluid, - or tap water. The idea is to just work with low
>pressure, and just make the thing crude and simple. If it turns out
>that you can get a pressure increase, - then we are on to
>something. Made simple enough, it would have a lot of applications.
>
>Is there any proffesional people that could help out ? Univerity ?
>
>In closing: Test out Xfig, or whatever, and let us see if we could
>pass drawings and ideas. If this list takes html, then the drawings
>could be inserted in the text.
>
>By the way, it is one of my first usages of xfig, - but it didn't
>take long before I figured out how to do some simple work with it.
>
>//ARNE
>
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>
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