LP pneumatics - ram exhaust hole size

**Danjr1** · 15th April 2015, 12:32

I'm working through the thought process of how a LP pneumatic flipper could work if the return was based upon a bungee cord (i.e. like a FP system). The bit im stuck on is the position and size of the hole that would need to be drilled into the bottom of the ram. As its low pressure, I'm thinking 0.5mm on the opposite side to the port so the gas has further to travel before exiting the ram. Obviously, I only have one shot at drilling this hole so any advice would be great. FYI, the ram is 50mm stroke and 80mm bore.

Cheers

Dan

**maddox10** · 15th April 2015, 12:36

If you want pure speed, the exhaust hole should as big as possible.

If you want adjustable speed, the exhaust hole should be adjustable in surface/diameter.

**Danjr1** · 15th April 2015, 12:43

Maybe start at 0.5mm on opposite side to the port then enlarge if required? I need to make sure that get all the power out of the ram due to the short stroke.

**Max** · 15th April 2015, 12:48

I think there is some confusion going on here, I think Mario is talking about the exhaust hole on the non-powered side (ie the side where you don't put in the compressed gas). Dan is talking about a vent hole in the pressurised side.
For an LP system you don't need a vent hole as LP 3/2 valves are so common and cheap that you can just use one of those to vent the gas.

**Danjr1** · 15th April 2015, 12:56

But flow is awful through common 3/2 valves (I'm planning to use a larger 2/2 NC valve) and I'm trying to keep the whole thing as simple/ compact as possible. It would literally be a FP set-up using LP components @ 10 bar.

**maddox10** · 15th April 2015, 15:21

http://www.teamonslaught.fsnet.co.uk/pneumatics.htm

**Gabe01** · 15th April 2015, 15:45

Assuming your competent with pnuematics then I wouldn't bother with low pressure. Keep it simple and go high.

**Gabe01** · 15th April 2015, 15:48

Do yourself a favour, if Flow is yours, build her a new chassis and bodywork, she's tired

**Danjr1** · 15th April 2015, 16:36

This would be my first venture into pneumatics and going FP would require me to outsource manufacture of the system which isn't something I'm keen on as I want to learn more about how to put these things together.

Ermmmm........ I dont own flow lol.