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 70 users online :: 4 registered, 0 hidden and 66 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Quick question

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

Quick question

Unread postAuthor: Fnord » Tue Jan 29, 2008 8:37 pm

Has anyone used a schrader valve as a check valve?

Logically, I think it should work, but I wanted to ask before I potentially ruin some fittings and jbweld.

(Edit; if it helps, I intend to use this on a homemade high pressure pump)
  • 0

Last edited by Fnord on Tue Jan 29, 2008 9:10 pm, edited 1 time in total.
Image
User avatar
Fnord
Major General
Major General
 
Posts: 2244
Joined: Tue Feb 13, 2007 9:20 pm
Location: Pripyat
Reputation: 7

Unread postAuthor: BigGrib » Tue Jan 29, 2008 8:45 pm

ive never done it but like you said theoretically it should work
  • 0

Yea, that's definitely going to get you at least a tazer.

<a href="http://www.youtube.com/watch?v=AkMkGOpAF4s">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
facebook.com/biggrib
User avatar
BigGrib
Colonel
Colonel
 
Posts: 652
Joined: Mon Oct 01, 2007 11:43 pm
Location: TriCities, WA
Reputation: 0

Unread postAuthor: Hotwired » Tue Jan 29, 2008 8:58 pm

If we're talking an air inlet check valve yes it works.

If we're talking as part of a system where you're looking for air to open the valve and pass through only one way then you might need fairly high pressure to open it.

I've got an unscrewed schrader in front of me (because I'm going to do something to it later...) and theres about a 2mm hole for air to pass through.

That 2mm hole is blocked by a tiny rubber faced poppet with a spring holding it shut, normally opened when being filled by a pin attached to it being physically forced down by the filling head.

Your call ^_^
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: mopherman » Tue Jan 29, 2008 10:15 pm

Sure, jsr has used them in this fashion with fine results, as have I. The only thing is the tiny flow, but if its a high pressure pump it doesnt have huge volume anyway. I say go for it
  • 0

searching for a modern day savior from another place,inclined toward charity,everyone's begging for an answer,without regard to validity,the searching never ends,it goes on and on for eternity
-Bad religion
User avatar
mopherman
Brigadier General
Brigadier General
 
Posts: 788
Joined: Sat Feb 03, 2007 8:20 pm
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Tue Jan 29, 2008 11:52 pm

When I fill with my shock pump, there's an o-ring between the pump attachment and the schrader, meaning the stem of the schrader doesn't get physically pushed down by the pin on the pump attachment, but air leaks through freely - so yeah, you should be fine.

Good luck with your pump ;)
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Hotwired » Wed Jan 30, 2008 5:27 am

*examines own shock pump*

Hey waddya know, theres no pin in there. Guess they're only on lower pressure pressure pumps for tyres and so on.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: mark.f » Wed Jan 30, 2008 6:52 am

While I'm sure it will work, I have a few suggestions.

Google "Presta" valves. They operate differently from Schrader valves, (they are held closed by pressure, not a spring, so they probably have a good surface area), and most attachments I've seen for filling them don't have a pin.

Why not just use a regular check valve? I've found them for as low as five bucks. It should last longer than a Schrader or Presta valve, in any case.
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Sponsored

Sponsor
 


Unread postAuthor: SPG » Wed Jan 30, 2008 6:56 am

You might want to look at a "presta" valve as well, they're the type used on high pressure racing bicycle tyres. They use purely air pressure to open (although you can push in the valve core to vent it, and I seem to remember that they actually have a bigger "port" area than a schraeder.
  • 0

<A HREF="http://www.paisleypeking.co.uk"><IMG BORDER="0" WIDTH="400" HEIGHT="64" SRC="http://www.paisleypeking.co.uk/images/signature.gif"></A>
User avatar
SPG
Major
Major
 
Posts: 364
Joined: Thu Feb 09, 2006 11:55 am
Reputation: 0

Unread postAuthor: Hawkeye » Wed Jan 30, 2008 7:59 am

So much easier to just make a custom check valve that the pump threads directly onto. All you need is a brass reducer that has a lip on the inside that will support an o-ring.
Can you guys not get threaded reducers? You can use 1/8 male-1/4 male, 1/8 male-1/4 female or 1/4 male-3/8 female. All of these have a nice lip on the inside that is perfect for housing a check valve. Then you can just put a fitting on the end of the pump that threads onto the smaller thread of the valve. No hose, zero or minimal deadspace.
  • 0


Hawkeye
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 462
Joined: Sun Jan 21, 2007 7:12 pm
Reputation: 0

Unread postAuthor: SpudFarm » Wed Jan 30, 2008 12:53 pm

why not be the first to make you own? when i think of it mabe i will i have for a long time been looking for a suitable check valve for a pump but never found one so i`ll mabe give it a try.
  • 0

User avatar
SpudFarm
Donating Member
Donating Member
 
Posts: 2563
Joined: Sat Nov 04, 2006 9:39 am
Location: Norway Trondheim area
Reputation: 0

Unread postAuthor: Hawkeye » Wed Jan 30, 2008 1:23 pm

Actually I believe I made the first high pressure pump with a homemade check valve on here.
It is so simple that I wouldn't even call it "making".
Assembly of parts that seemed custom made for the job is more like it.
The extent of custom work involved filing out the stop in a reducer so that the pump rod could slide freely, drilling a hole in an end cap and filing a hex nut to a round shape by chucking it in a drill and spinning it against a file. Real tough stuff.
  • 0


Hawkeye
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 462
Joined: Sun Jan 21, 2007 7:12 pm
Reputation: 0

Return to General Spud Cannon Related

Who is online

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

Reputation System ©'