SpudFiles

Hi all.

I got some time to do something else than working on my hybrid.
I decided to make a steel 2" piston valve.

Something to know:
- everything is made out steel (except the piston)
- piston is made of ACULON (i don't know the exact name for America)
- the metal fittings are sealed with an special thread sealant, i can hold pressure upto 17bars
- piston seat is a piece of 5/4" pipe, pipe sits in a 2" to 5/4" bushing

Here a some pics:









More testing this week.
I ordered some pvc pipe and fittings. The pvc is PN16.

Airpress

Very nice. Must weigh a ton!!! cant wait to see it in action!!

Indeed, it's not light at all. :p
That's why I bought some pressure rated pvc pipe.
After much searching I found a dealer in the little country Belgium!

if you want to be able to use your gun to its full potential, use more metal instead of pvc. unless the pvc is different elsewhere, it wont hold 17 bars. im from the US and the pvc here cant nearly withstand that much pressure. just a suggestion. If you dont have a heavy duty compresser, maybe pvc would be the best choice

The pvc is pressure rated for 16bars of waterpressure, not air.
I won't go any higher than 7 to 8 bar. When I want to get more power, I can easliy replace it with a steel chamber.

Some more details:
airchamber: 75mm 90cm long
barrel: 50mm 1,5m long

I will use this cannon where I haven't acces (field) to an aircompressor. That's why I will stuck to a pvc chamber. I will use a bicycle pump.

oh sorry, i accidently typed in 61 bar into my converter:p yeah, pvc would be fine for those pressures as long as the size isn't too big.

Looking good but I reckon the barrel seat might extend too far in to the tee and reduce flow.

@ Mr Crowley,

Indeed, the seat is yet too long. I will test it when I have my chamber.
When I need to shorten it, I can. When it is too short, that would be a different problem. Then I need to buy a new 2" bushing and weld a new the pipe in it.

Something else, the gap between the fitting and piston is 0.5mm.
I might think this is to small, or not?
I've made a piston valve before but it was only 1"piston with 1/2" seat with the same gap as now. It worked great!

http://www.aculon.com/technology.php

Not sure if it's a material or a coating....

MrCrowley wrote:Looking good but I reckon the barrel seat might extend too far in to the tee and reduce flow.

If need be he could just cut off a inch or whatever needs, to be cut off. Not a big deal and smooth down rhe edge of course.

mattyzip77 wrote: If need be he could just cut off a inch or whatever needs, to be cut off. Not a big deal and smooth down rhe edge of course.

I figured as much, thought that would be assumed

airpress wrote:Something else, the gap between the fitting and piston is 0.5mm.
I might think this is to small, or not?
I've made a piston valve before but it was only 1"piston with 1/2" seat with the same gap as now. It worked great!

I believe you can (IIRC) calculate the area between the piston and then piston housing (cross-sectional area of the piston housing minus the cross-sectional area of the piston) and then compared that to the cross-sectional area of the flow through the pilot valve. I'm not sure how much larger the pilot valve cross-section should be though.

Today the pipes arrived.
I cutted them and glued the needed fittings to the pipes.


Here a close up of the pvc markings.
The pipe is rated for 16bars(PN16). (waterpressure)


I also screwed the pilot area together.

Very nice but why did you use sch 80 for the barrel? Also wait the full 24 hours for the glue to dry. This thing will have some serious power..

All those pressure rated pvc pipes here have the same color.

Yep, I will wait 24 hours. It said on the glue container.

A little preview.

Just slight screwed the airchamber and barrel to the valve.





Tomorrow I will make 2 support for between the barrel and chamber.
I will make it the same roundness of the airchamber and barrel.
The material used will be 1cm thick black pvc sheets.

Just to make it clear, the valve weighes more than the chamber and barrel.