Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 13 users online :: 3 registered, 0 hidden and 10 guests


Most users ever online was 106 on Sat Jun 14, 2014 4:35 pm

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Self-closing piston valve (brass fittings)

Come find a how-to on how to do something, or come write your own for other people.
Sponsored 
  • Author
    Message

Self-closing piston valve (brass fittings)

Unread postAuthor: MRR » Mon Mar 09, 2009 10:22 am

This is the way I build a high pressure self-closing piston valve (barrel sealer).

min. actuation pressure: 30 psi (varies due to the used spring and piston)

The parts:
1/2" quick connect (only to connect a blowgun, not to pressurize)
3/4" female to 1/2" male
1" female to 3/4" male
1" nipple (find one with a smooth surface inside)
1" tee
3/4" hose barb
1" to 3/4" reducer
1 bolt 2 fitting nuts
3 sealing gaskets (3/4")
1 washer -> size of the sealing gasket
2 washers -> I.D. of the 1" nipple

Image

Step 1:
Screw the 3/4" hose barb into the 1" to 3/4" reducer and then the reducer into the 1" tee.
Nice about these hose barbs is that they have short threads, so there is enough space to add multiple barrels.

Image

For this valve I chose a large tee compared to the "barrel" to have a good air flow and a smaller pilot chamber.

Image

Step 2: build a piston (optional way)
This is basically a bolt piston but with two tricks I want to show you.

If you have ever build a bolt piston you might have realized that it is not that easy to get the washers into one line. Simply take two nuts and grind one side of them to form a cone. This way your washers are always centered (you can see it on the right nut on the picture).

To make the piston seal, take two sealing gaskets that are little smaller than your housing (in this case 1" nipple -> 3/4" gasket). Place them between two washers and nuts. Now screw the nuts so that the gaskets squeeze out. This way you get a perfect sealing piston.

Image

Step 3: Assembling of the pilot section
Quick connector -> 1/2"male to 3/4"female -> 3/4"male to 1" female

Optional: Quick connector -> 1/2"male to 1" female (if you find one, even better)


Step 4: Finding the right spring (this step needs some tweaking)
You have to find a spring that is not to strong or to weak.

to strong: The piston only opens at very high pressure with bad flow or it doesn't open at all.
to weak: The piston doesn't seal and the air leaks out of the barrel.

If you think that you have the perfect spring but the air still leaks out of the barrel then your piston might seal to well in it's housing. A little equalization should be installed.



Picture of the pilot chamber. It's already small but still improvable. The valve can be actuated with a blowgun @ 30 psi.

Image
  • 0

Last edited by MRR on Mon Mar 09, 2009 12:22 pm, edited 1 time in total.

MRR
Major
Major
 
Posts: 362
Joined: Tue Feb 17, 2009 2:29 pm
Reputation: 0

Unread postAuthor: jmeyer1022 » Mon Mar 09, 2009 10:54 am

Great how-to for those beginning to work with metal rather than PVC, and just informative in general. All your posts been great so far keep it up!
  • 0


jmeyer1022
2nd Lieutenant
2nd Lieutenant
 
Posts: 200
Joined: Sun Nov 09, 2008 4:50 pm
Reputation: 0

Unread postAuthor: Combustion Monkey » Mon Mar 09, 2009 11:02 am

Nice clean job. Its amazing how similar this is to the piston that I put together for my hybrid project, except that mine is a chamber sealer that is blown open by the combustion. Its interesting to see how two independent ideas can come out so much alike.
  • 0

User avatar
Combustion Monkey
Master Sergeant
Master Sergeant
 
Posts: 153
Joined: Sun Jan 11, 2009 3:01 pm
Reputation: 0

Unread postAuthor: POLAND_SPUD » Mon Mar 09, 2009 11:17 am

Great how-to for those beginning to work with metal rather than PVC, and just informative in general. All your posts been great so far keep it up!

I second that... lol Jmeyer that's exactly what I had in mind...

@MRR I like that you used a hosebarb that was very clever and simple at the same time


feel free to add more good stuff :wink:
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5384
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 7

Unread postAuthor: mark.f » Mon Mar 09, 2009 11:56 am

The valve should seal without a spring...
  • 0

WIP: belligerent mixture of steel and pressurized reactants
COMPLETION: several months out
User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3278
Joined: Sat May 06, 2006 11:18 am
Location: Louisiana
Country: United States (us)
Reputation: 13

Unread postAuthor: MRR » Mon Mar 09, 2009 12:19 pm

Thanks fore the kind comments, I really appreciate that.

@mark
The concept of that valve is to power a semi auto. The quick connect is only to attach the blowgun. I fill the chamber from another place, it's simply faster than pushing the pressure through a small equalization hole.
  • 0


MRR
Major
Major
 
Posts: 362
Joined: Tue Feb 17, 2009 2:29 pm
Reputation: 0

Unread postAuthor: jmeyer1022 » Mon Mar 09, 2009 1:04 pm

Quick question MRR, What's total cost for the valve? I'm looking to build a copper pneumatic to go with the fridge compressor I recently got. I love my 2" golf ball cannon but the neighbors don't.
  • 0


jmeyer1022
2nd Lieutenant
2nd Lieutenant
 
Posts: 200
Joined: Sun Nov 09, 2008 4:50 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: MRR » Mon Mar 09, 2009 1:15 pm

I got the parts + a 1 meter copper barrel from a friend for 20€~25$ (he is a plumber and doesn't pay VAT).
  • 0


MRR
Major
Major
 
Posts: 362
Joined: Tue Feb 17, 2009 2:29 pm
Reputation: 0

Unread postAuthor: POLAND_SPUD » Mon Mar 09, 2009 3:36 pm

I suggest using malleable iron fittings where possible to cut costs
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5384
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 7

Unread postAuthor: daberno123 » Mon Mar 09, 2009 3:49 pm

I'm a bit confused on how you got the hose barb inside the tee.

Can you screw the hose barb into the reducer from side with the 1" threads on the outside? I thought the threads would only match up if you screwed it in from the 3/4" side?

Could someone clarify this for me?

Other than that its a great write-up.
  • 0

User avatar
daberno123
Colonel
Colonel
 
Posts: 594
Joined: Mon Nov 19, 2007 5:56 pm
Location: Ohio
Reputation: 0

Unread postAuthor: sniper hero » Mon Mar 09, 2009 4:21 pm

great work
I made something similar before but without a spring

daberno123: you can screw the hose barb in the other side of the 3/4 reducer
then screw that with the hose barb pointing in inside the T

there is enough space left on the other side for a barrel
  • 0

proud member of dutch spud clan
coming: semi auto pellet sniper:D
User avatar
sniper hero
Captain
Captain
 
Posts: 332
Joined: Fri Mar 07, 2008 3:12 pm
Reputation: 0

Unread postAuthor: SpudsMcGee » Mon Mar 09, 2009 4:32 pm

jmeyer1022 wrote:Great how-to for those beginning to work with metal rather than PVC, and just informative in general. All your posts been great so far keep it up!


I third that! (In a corny tone)
This how-to is just as good as all you're others and I think it will benefit all spudders alike. (In a noble tone)
  • 0

(\_/)
(o.o)
(><)

Current Project: Slasher Valve
User avatar
SpudsMcGee
Master Sergeant
Master Sergeant
 
Posts: 160
Joined: Mon Nov 10, 2008 10:03 pm
Reputation: 0

Unread postAuthor: daberno123 » Mon Mar 09, 2009 6:10 pm

sniper hero wrote: you can screw the hose barb in the other side of the 3/4 reducer
then screw that with the hose barb pointing in inside the T


Do you have to grind away any lip or anything on the reducer?
  • 0

User avatar
daberno123
Colonel
Colonel
 
Posts: 594
Joined: Mon Nov 19, 2007 5:56 pm
Location: Ohio
Reputation: 0

Unread postAuthor: LikimysCrotchus5 » Mon Mar 09, 2009 10:36 pm

Looks nice and pricey cause of brass. The look reminds me of a "French QEV" or as they like to call it.

Nice job
  • 0

4SPC, My 4" piston 3" porting cannon
Memo:
Fix up copper cannon
Fix up 4SPC
Start Stirrup pump
Start Toolies piston bazooka
User avatar
LikimysCrotchus5
Brigadier General
Brigadier General
 
Posts: 1100
Joined: Tue Sep 04, 2007 10:16 pm
Reputation: 0

Unread postAuthor: far_cry » Tue Mar 10, 2009 9:44 am

nice man this is so pretty

so how much pressure can handle ! the max ?
  • 0

ImageImage
User avatar
far_cry
Donating Member
Donating Member
 
Posts: 317
Joined: Wed Aug 20, 2008 3:59 pm
Reputation: 0

Next

Return to How-To Guide Database

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'