SpudFiles

cool thanks, just trying to calculate shots out of one using the calculator program someone put on here... forget who it was exactly

No problem, I figured ~ 400 shots from 5lbs for my copper gun.

Fill for calculation was 7.25cu.in @ 400psi.

That's a lot of pumping I won't have to do!

ilovetoblowthingsup wrote:cool thanks, just trying to calculate shots out of one using the calculator program someone put on here... forget who it was exactly

http://www.spudfiles.com/forums/how-muc ... t7133.html

NICE FIND!!

i dont know if it works the same over in aussie land just giving them away but im gonna try

these tanks look sweet... i wonder how much time its takes to pump them to 400 psi with a fridge compressor... you might consider getting another one to speed up the process

Poland Spud;

I calculate about 35 minutes.

I will try hooking the fridge compressor inlet up to the shop air compressor, this should reduce the fill time to about 4 minutes.

(This as per Ragnaroks suggestion some time ago)

yeah I remember that he suggested it... it's a great idea... if you succede post a vid or something

Gippeto wrote:Poland Spud;

I calculate about 35 minutes.

I will try hooking the fridge compressor inlet up to the shop air compressor, this should reduce the fill time to about 4 minutes.

(This as per Ragnaroks suggestion some time ago)

Would that make the compressor able to perform higher output too? Honestly, im clueless on how these things work even though i own one myself

yeah it would work - I'd like to explain this but english is not my fist lg so it would take me a lot of time so instead I'll quote ragnarok -->

Air at 120 psi is 9 times denser than air at atmospheric pressure. If you put that air through a fridge pump, then it will pump 9 times the volume in the same time.

With the right setup, you could use the shop compressor for the first 120, then pump the denser air from it instead to get higher air volumes through the fridge pump in the same time. Instead of 280-300 cc per minute, you've got 2500 cc or more. That's a big difference.

The flow of even one low end shop compressor could supply 3 or 4 fridge compressors with this denser supply. If you can get said compressors cheaply, then you've got quite an arrangement. That would fill a 27 litre container in under two minutes I guess.

POLAND_SPUD wrote:yeah it would work - I'd like to explain this but english is not my fist lg so it would take me a lot of time so instead I'll quote ragnarok -->

Air at 120 psi is 9 times denser than air at atmospheric pressure. If you put that air through a fridge pump, then it will pump 9 times the volume in the same time.

With the right setup, you could use the shop compressor for the first 120, then pump the denser air from it instead to get higher air volumes through the fridge pump in the same time. Instead of 280-300 cc per minute, you've got 2500 cc or more. That's a big difference.

The flow of even one low end shop compressor could supply 3 or 4 fridge compressors with this denser supply. If you can get said compressors cheaply, then you've got quite an arrangement. That would fill a 27 litre container in under two minutes I guess.

So far i follow you my question was whether the fridge compressor could make more pressure with pressurized air inlet, but in the meantime i have already figured out that it wont make any difference but the increased flow.

yeah I think it would.
let me expleain you this the way I see it ->sice a fridge pump is just a piston pump each piston stroke compresses air. therefore if you provide higher pressure to the air input the piston would compress already compressed air - but it would require the same amount of power becasue the pressure doesn't matter here - the ratio of compression is important

ok this will be easier to undestand. lets imagine that you are inside a sealed room - the pressure inside is 10 bar and you try to pump your spudgun using a bike pump - now the question is what is the pressure inside the gun ? is it 5 bar becasue that's the highest pressure your pump can achieve? or is it higher than 10 bar ? I think it's easier to understand it now

I am not sure what is the pressure inside the fridge compressor casing... I am almost sure that these pumps are sealed but I have no idea whether the pressure inside the casing is 1 atm or is it affected by the pressure at the air inlet ? (most likely the later)

POLAND_SPUD wrote:yeah I think it would.
let me expleain you this the way I see it ->sice a fridge pump is just a piston pump each piston stroke compresses air. therefore if you provide higher pressure to the air input the piston would compress already compressed air - but it would require the same amount of power becasue the pressure doesn't matter here - the ratio of compression is important

ok this will be easier to undestand. lets imagine that you are inside a sealed room - the pressure inside is 10 bar and you try to pump your spudgun using a bike pump - now the question is what is the pressure inside the gun ? is it 5 bar becasue that's the highest pressure your pump can achieve? or is it higher than 10 bar ? I think it's easier to understand it now

I am not sure what is the pressure inside the fridge compressor casing... I am almost sure that these pumps are sealed but I have no idea whether the pressure inside the casing is 1 atm or is it affected by the pressure at the air inlet ? (most likely the later)

I can tell that you and me think very much alike, as those where my exact thoughts on this. however one of my friends convinced me that he knew alot about this stuff and told me that altering with the input pressure wouldnt affect the maximum output of the compressor. Im all ears if someone wants to tell me something else, or even better, document something else. As said before, i dont know squat about how these things work, so you can get me to believe almost anything if you use enough fancy words

well... we have the same problem

I am almost sure it would work if the pressure inside the compressor and conseqently the pressure acting on the other side of the piston is the same as the pressure of air at the air input
we have to wait till gippeto test it
one thing is sure if this would work as planned it would be a real milestone

POLAND_SPUD wrote:well... we have the same problem

I am almost sure it would work if the pressure inside the compressor and conseqently the pressure acting on the other side of the piston is the same as the pressure of air at the air input
we have to wait till gippeto test it
one thing is sure if this would work as planned it would be a real milestone

It would definately be, but with that other problems come along. how much pressure do you think the thin copper tube sticking out of the compressor can take? i can see no easy way of reinforcing those. but well, lets not make a problem of somethings thats not yet.
Looking forward to hearing from someone who is going to test this

Those little copper pipes hold a hell of alot of pressure if sch 40 1/2'' pvc can hold 400psi than I think that the small copper ones could hold 8x more. Did you see btbs death ray machine pistol that has some of that copper pipe on it but I forget how much pressure he puts in it.