Crap where to start??
Technician1002 wrote:If the piston has equal pressure (multi X bar pressure) on both sides before firing, that will be fine by itself. The issue I see is the pilot vent will be unbalanced and may open the piston under pressure before firing.
A slight modification can make the pilot vent balanced too. Put the pilot vent port between the o rings and balance the pressure on the pilot vent. When fired, the main valve and pilot vent opens. Before firing, the piston and pilot vent are balanced.
the way I planned it, it would have been an isolated pilot to allow me to control the opening pressure by controlling the pilot pressure.
to put the vent hole between the o rings to make it balanced sounds good to me, I will most likely incorporate this into the design. thanks for the advice
SpudBlaster15 wrote:While this valve will work, the design is very poor, to put it bluntly.
Your piston area ratio is actually lower than 1:1, which means that without 300PSI+ in the pilot chamber, your valve opening pressure will be far less than optimal for even low to moderate mixes.
I'm also very concerned with the cast aluminum valve body. Aluminum castings (Especially those done using a backyard foundry) are very prone to defects, namely trapped gas bubbles, and without proper heat treatment, aren't very strong to begin with. Which alloy did you use, and do you have any plans to artificially age harden it?
like I said I was planning this to be an isolated pilot design.
Yes Aluminum castings (Especially those done using a backyard foundry) are very prone to defects, but that is only because most backyard foundry men don't follow good foundry practice (and I do follow good foundry practice) 1 they don't control their furnace atmosphere and 2 they don't flux nor degas and to show you that this casting don't have absorbed hydrogen(the gas that causes gas bubbles in castings) I took a part of the gating system from this casting that you would most likely find bubbles if you got any absorbed gas, and I cut a section of it and polished it to some degree to show lack of bubbles
as you can see there is no gas in this blind riser meaning it is nice and solid metal. the alloy used, I cannot remember the name of this alloy, but I can tell you that is a alloy that is a bit more malleable than most cast alloys. I am still looking into the artificial age hardening, still looking for a local place to get it done.
besides the most critical parts of this valve is going to be sleeved in seamless hydraulic tubing (shown on concept drawing)
-_- wrote:
kenbo0422 wrote:
Your pressure vessel looks to be thick enough to withstand 25x easily, if that is steel I'm looking at. Check it for cracks with a good magnifying lens.
It could take 70x easily if he makes the end cap and barrel holder strong enough, because its made for hydraulics they run at like 2,500psi+
pic of the end cap of this chamber
I also just got to add that the cast valve body is 16mm thick at the thinnest point
If you guys still feels that a cast valve body is unsafe or a bad idea, I'll skip the cast valve body and make this a burst disc cannon
