VH_man wrote:I see we disagree on how piston bounce exists... Leaving me to wonder..... Whos right? to the testing board!
Like you said it is a complex process with lots of variables involved. In addition to the increasing pressure from the rapidly moving piston you also have to consider the rapidly falling chamber pressure (which is what you were describing I believe). In simplest terms if pilot pressure is greater than chamber pressure the piston will want to close again, so you want to avoid that by having a sufficient exhaust valve or by sizing your valve such that you get as much air out of the pilot as you can before the piston starts moving. The latter method is usually what I prefer, but I didn't have the luxury of selecting the dimensions on this valve.
starman wrote:...With that built-in seat, it's almost like it was designed for this application....
I would have consided a little larger diameter chamber just to keep the length down some, but I know you were just using a chamber you had a around.
Yep just slap in a piston and go. I also ran across some check valves that are built in wyes and use pistons, so all you would have to do is modify the piston to turn it into a piston valve, but they aren't as common as strainers so I never actually got one.
Here is an example of the check valves http://www.haywardflowcontrol.com/pages/pro_cv_05.html There are clear ones out there too.
The chamber was partially because it was something I already had, but also because I didn't want it to be too front heavy. Letting the chamber extend back a ways helps balance it out some.
jackssmirkingrevenge wrote:Nicely done as always it would be great to have it filmed with a reasonably high speed camera to assess piston behaviour with different pilot valves vis a vis performance.