Piston Valves Explained Visually

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

Tue Oct 23, 2007 10:46 am

Can someone answer this for me-
Is it possibly to have too much pilot volume? I have a 3" Tee, and the pilot volume is about the size of a 3" cap.
User avatar
Pete Zaria
Corporal 5
Corporal 5
Posts: 954
Joined: Fri Mar 31, 2006 6:04 pm
Location: Near Seattle, WA

Tue Oct 23, 2007 10:53 am

octane89 wrote:Can someone answer this for me-
Is it possibly to have too much pilot volume? I have a 3" Tee, and the pilot volume is about the size of a 3" cap.
Yes, too much pilot volume is a common problem. A larger pilot valve does help, though it's best to try to reduce this volume somehow, either by re-designing the valve or filling the volume with something (foam anyone?).

A picture would be helpful...

Peace,
Pete Zaria.
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

Tue Oct 23, 2007 10:58 am

I'll have a pic soon and better explanation, but It's a new type of sealing piston Im working on, and where the piston slides back is the pilot volume (obviously), but I don't want to restrict the flow by not having it open enough.
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

Tue Oct 23, 2007 11:23 am

Here's a pic to help get an idea of what Im doing.
Attachments
Here's what it looks like together. The cap and tee will be held together by a 4" coupling.
Here's what it looks like together. The cap and tee will be held together by a 4" coupling.
bar-valve.JPG (36.66 KiB) Viewed 9216 times
Here's what I have so far. I haven't finished everything yet so so try to imagine it a bit. Hence why I did the paint drawing.
Here's what I have so far. I haven't finished everything yet so so try to imagine it a bit. Hence why I did the paint drawing.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Tue Oct 23, 2007 11:28 am

Yes, too much pilot volume is a common problem. A larger pilot valve does help, though it's best to try to reduce this volume somehow, either by re-designing the valve or filling the volume with something (foam anyone?).
words of reason, music to my ears :)

Octane, the disc that seals with the barrel needs to be the same diameter as your rear disc otherwise it won't be stable and won't work.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

Tue Oct 23, 2007 11:33 am

Thats something I figured when I started to make the seals. But I have that part figured I believe. I was just gonna make it the same size, but cut away some of the unnessecary sections to allow it to "flow" back easier.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Tue Oct 23, 2007 11:40 am

Apologies for the sh!te paintshop, but you mean like in the attachment? that would work well.
Attachments
piston.JPG
piston.JPG (21.16 KiB) Viewed 9207 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

Tue Oct 23, 2007 11:44 am

Yea, essentially the same unless I cut it differently.
User avatar
wangpushups
Specialist
Specialist
Posts: 185
Joined: Sun Sep 23, 2007 12:28 pm
Location: Wisconsin

Sat Nov 24, 2007 11:49 am

This helped me out a lot, thanks.
User avatar
f.c
Specialist 3
Specialist 3
Posts: 340
Joined: Sun Jul 08, 2007 2:40 am

Tue Dec 11, 2007 10:03 pm

the coaxial design doesn't seem to be showing up just my luck considering i needed it.
can i be a sasquatch ?
Hawkeye
Specialist 4
Specialist 4
Posts: 462
Joined: Sun Jan 21, 2007 7:12 pm

Tue Dec 11, 2007 10:29 pm

Too bad that's the only coaxial diagram on here.
User avatar
MrCrowley
Moderator
Moderator
Posts: 10078
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Been thanked: 3 times

Tue Dec 11, 2007 10:39 pm

f.c wrote:the coaxial design doesn't seem to be showing up just my luck considering i needed it.
The co-axial animation is working for me, your talking about the one on the front page right?
clide
Corporal 3
Corporal 3
Posts: 784
Joined: Sun Mar 06, 2005 3:06 am
Location: Oklahoma, USA

Donating Members

Tue Dec 11, 2007 11:36 pm

f.c wrote:the coaxial design doesn't seem to be showing up just my luck considering i needed it.
Not sure why it wouldn't be working, Try <a href="http://gbcannon.com/flash/coax.swf">this link</a>

Also the theory behind all of them is the same, so using another one would probably still let you learn the concept.
User avatar
f.c
Specialist 3
Specialist 3
Posts: 340
Joined: Sun Jul 08, 2007 2:40 am

Wed Dec 12, 2007 1:52 am

thank you. its great to see a forum where people actually help each other out spudfiles get a 10/10 in my opinion.
can i be a sasquatch ?
anthony5640
Private
Private
Posts: 11
Joined: Tue Jul 24, 2007 2:35 am

Sat Jan 12, 2008 8:54 pm

how do i make a piston?
Post Reply