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 50 users online :: 4 registered, 0 hidden and 46 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

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

The Team
Administrators
Global Moderators
global_moderators.png CS

air tank supply

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

air tank supply

Unread postAuthor: jon_89 » Fri Aug 22, 2008 1:19 am

I was thinking of using one of those big propane tanks for an air supply. I would charge the propane tank to about 110 psi. Then I would regulate it to about 90 psi. If my chamber was 1 inch x 30 inches. How would I figure out how many shots per tank? Thanks in advance
  • 0


jon_89
Colonel
Colonel
 
Posts: 607
Joined: Wed Apr 11, 2007 9:50 pm
Reputation: 0

Unread postAuthor: POLAND_SPUD » Fri Aug 22, 2008 3:32 am

obviously it won't be able to provide air at 90psi when the air inside the tank is below 90 psi :wink:
thus the volume of air that you can use equals --> (volume of the tank) * (the difference between the tank pressure and desired pressure)

110psi - 90 psi = 20 psi

then convert psi to atm
20 psi = ~1.37atm

and finally
(1.4atm * the volume of the tank ) / ( 6atm * chamber volume) = number of shots per tank






I don't have much time to explain in more details - sorry I got to go

ohh one final advice... pump the tank to higher pressure (in theory they can handle up to 20atm) to get more shots per fill... even 130 psi will increase teh numer of shots you can get from it by factor of 2

EDIT
sorry 20 psi is more like ~1.4 atm not ~1.7... wel it seems I am not that good at rough esstimates
  • 0

Last edited by POLAND_SPUD on Sat Aug 23, 2008 6:08 am, edited 1 time in total.
Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Unread postAuthor: jon_89 » Sat Aug 23, 2008 12:22 am

So if my math is correct I should get 13 shots. Now are these 13 shots at 90psi though?
  • 0


jon_89
Colonel
Colonel
 
Posts: 607
Joined: Wed Apr 11, 2007 9:50 pm
Reputation: 0

Unread postAuthor: POLAND_SPUD » Sat Aug 23, 2008 6:14 am

they should be at 90 psi assuming that your regulator works fine

I don't know if your math is ok because I don't know which tank you were talking about when you said 'those big propane tanks'.... what is its volume?
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Unread postAuthor: jon_89 » Sat Aug 23, 2008 1:53 pm

Whoops sorry about that. I think they are 5 gallons. 1 gallon eqauls 231 cubic inches. So a 1155 cubic inch tank.
  • 0


jon_89
Colonel
Colonel
 
Posts: 607
Joined: Wed Apr 11, 2007 9:50 pm
Reputation: 0

Unread postAuthor: potatoflinger » Sat Aug 23, 2008 2:39 pm

While we are on the topic (sorry to hijack your thread jon_89) would this work to find the number of shots per tank?

(volume of tank*tank pressure)/(volume of chamber*chamber pressure)
  • 0

It's hard to soar with eagles when you're working with turkeys.
User avatar
potatoflinger
Brigadier General
Brigadier General
 
Posts: 1136
Joined: Thu Nov 02, 2006 3:26 pm
Location: Maryland
Reputation: 1

Unread postAuthor: POLAND_SPUD » Sat Aug 23, 2008 3:09 pm

yeah you'll get about 11 shots (i know you said 13 but I assumed that's becasue of the error in my first post (20 psi is ~1.4atm not 1.7atm - sorry about that I didn't have time to calculate then)

@potatoflinger - I assume you don't want to regulate it down to a set pressure so it's a bit different now.... each time you are going to fill the gun the pressure inside the gun and the tank is going to fall and equalize... so after each shot the pressure will fall...

but at the moment I am too drunk and to be honest I've never been good at maths.... maybe I'll pm DYI to help us.... he seems to be good at stuff like this
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Sponsored

Sponsor
 


Unread postAuthor: potatoflinger » Sat Aug 23, 2008 4:11 pm

POLAND_SPUD wrote:@potatoflinger - I assume you don't want to regulate it down to a set pressure so it's a bit different now.... each time you are going to fill the gun the pressure inside the gun and the tank is going to fall and equalize... so after each shot the pressure will fall...

No, it will be regulated, but I just wanted to know if the method would work.

For example, a 100 cubic inch air tank at 100 PSI, and a gun with a 20 cubic inch chamber regulated to 50 PSI.
(100*100)/(20*50)=10
So if that method is correct, I would get 10 shots per tank, the only problem is that I don't know whether that method is correct or not.
  • 0

It's hard to soar with eagles when you're working with turkeys.
User avatar
potatoflinger
Brigadier General
Brigadier General
 
Posts: 1136
Joined: Thu Nov 02, 2006 3:26 pm
Location: Maryland
Reputation: 1

Unread postAuthor: DYI » Sat Aug 23, 2008 4:16 pm

[(TP-CP)*TV]/(CP*CV) = # of shots before tank drops below intended chamber fill pressure, where:
TP = tank fill pressure
TV = tank volume
CP = intended chamber fill pressure
CV = chamber volume
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: marpat » Sat Aug 23, 2008 4:55 pm

isnt the propane in those tanks liquified because if it was then u would get a lot more shots off at 90 psi because the liquid propane would expand to take the place of the leaving propane represusurizing the tank in a way
  • 0

User avatar
marpat
Corporal
Corporal
 
Posts: 75
Joined: Thu Jun 05, 2008 9:31 pm
Reputation: 0

Unread postAuthor: POLAND_SPUD » Sat Aug 23, 2008 6:21 pm

@DYI so this is basically what I've written here.... At least once my math is ok :D

@marpat We are talking about using used propane tanks as air reservoirs... not about using propane
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Unread postAuthor: jon_89 » Sat Aug 23, 2008 7:21 pm

According to DYI eqaution I would get 5 shots. I think though I will get one of those 5 gallon air tanks for like $20 and it has a pressure gauge and air hose.
  • 0


jon_89
Colonel
Colonel
 
Posts: 607
Joined: Wed Apr 11, 2007 9:50 pm
Reputation: 0

Unread postAuthor: POLAND_SPUD » Sat Aug 23, 2008 7:46 pm

Ok at least once I am right....


of course you have to put pressure in atm not PSI.... 1atm = 14.7 PSI

otherwise it won't make any sense
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Return to Pneumatic Cannon Discussion

Who is online

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

Reputation System ©'