Low Pressure

[snoopay700]

I figured this doesn't fit in paintball talk really so i brought it here. What is the lowest output pressure that a marker has that can still achieve normal velocities (around 280-300 fps). Like what is the least amount of pressure you need to get a paintball going that fast out of the barrel? (like what psi)

Also, do you need an lpr for an msv-2 to function, or can you just hook it straight up to the msv-2 and it won't break anything.

Both of these are things i've just been wondering and if anyone can help me i'd reallly appreciate it.

[FlawleZ]

I think I've heard of 35-45 psi operating pressure. Sadly I can't even remember which gun it was. I'm sure there others that have stupid low operating pressures.

[snoopay700]

I think I've heard of 35-45 psi operating pressure. Sadly I can't even remember which gun it was. I'm sure there others that have stupid low operating pressures.

So they get the ball out of the barrel at 280 fps with 45 psi? That's actually quite amazing. Can they cycle fast, like at least 15 bps without shootdown?

[SR_matt]

depends on the marker system

my friend had his cocker set up at 70 psi (he had to really play with springs and adjsut stuff) he ran it out of an adjustable tank into a gas thru grip and had bored out some holes so there was a lot of volume.

a kid i had worked with at a field had his impluse set up to run about 45ish (ended up blowing out the valve because it had to put so much volume through but at such a low pressure)

you gun might have 200 psi in the resevoir but the pressure that actualy gets behind the ball is very low (http://www.automags.org/resource/tec...rrel_eff.shtml 50-125 psi in the barrel is average)

pressure1*volume1= pressure2*volume2, thus high pressure low volume or low pressure high volume (you use the same amount of air but it depends on the pressure and volume (thats why people argue about lp being less efficent) , but there is some places that say lp is slightly less efficent but the fact you can shoot lower into the tank counters that)

so in short its not a question of how low can you take the psi but how much volume can you get behind it fast that will determine how low you can go

-matt

[Pneumagger]

as long as there is there just enough positive pressure behind the ball to overcome the barrel drag against the ball - you can get to 300fps with a long enough barrel and a constant pressure behind the ball. Now that a constant low pressure in practice requires a huge (like infinite huge) dump chamber volume.

Your question is heavily dependent on the actual barrel drag on the ball as well as the length of the barrel you want to use. The lower the pressure you use behind the ball, and the longer the barrel you use, the larger your dump chamber will have to be to supply a seemingly constant supply of air.

Think of blowguns (like aborigines use). They use a near 5 foot barrel and probably a near constant supply of pressure from the mouth (10psig perhaps) to shoot a dart VERY VERY fast and accurate.

In summary: Given a large enough dump chamber to hole constant pressure, as long as the pressure force is higher than the barrel/ball friction force - all you need is a long enough barrel.


EDIT: I thought this might help, but looking at commercial "Low Pressure Paintball Guns" you'll notice they all have large internal reservoirs - for example the AKA Viking, Angel Front Volumizers, Spyder LPC's (low pressure chambers), old school matrix LPC's, etc....

[snoopay700]

as long as there is there just enough positive pressure behind the ball to overcome the barrel drag against the ball - you can get to 300fps with a long enough barrel and a constant pressure behind the ball. Now that a constant low pressure in practice requires a huge (like infinite huge) dump chamber volume.

Your question is heavily dependent on the actual barrel drag on the ball as well as the length of the barrel you want to use. The lower the pressure you use behind the ball, and the longer the barrel you use, the larger your dump chamber will have to be to supply a seemingly constant supply of air.

Think of blowguns (like aborigines use). They use a near 5 foot barrel and probably a near constant supply of pressure from the mouth (10psig perhaps) to shoot a dart VERY VERY fast and accurate.

In summary: Given a large enough dump chamber to hole constant pressure, as long as the pressure force is higher than the barrel/ball friction force - all you need is a long enough barrel. Super Low Pressure = Super Long Barrel :: Super Short Barrel = Super High Pressure

Makes sense, i should've been thinking about that but i guess it just wasn't on my mind.

Anyway, can you answer my second question, can you run air through an msv-2 without an lpr, and if not how high of a pressure can you get out of an lpr?

[Pneumagger]

Makes sense, i should've been thinking about that but i guess it just wasn't on my mind.

Anyway, can you answer my second question, can you run air through an msv-2 without an lpr, and if not how high of a pressure can you get out of an lpr?

They can handle a max of 125psi working pressure as listed on the website if I remember correctly. As far as LPR pressure, there is no difference in a a basic LPR versus most normal inline regs. The only difference is really the use of a small spring that is "weak" - meaning it can only allow a weak pressure to pass. So max LPR pressure is strictly dependent on the strength of the mainspring, and the pressures the seals are designed to hold.

On my personal pneumag, I use a palmers fatty inline regulator that was made to pass HP to the mag valve and LP through the rail.

[SR_matt]

On my personal pneumag, I use a palmers fatty inline regulator that was made to pass HP to the mag valve and LP through the rail.

i assume you have 2 "imputs" and 1 out put so it works more so the hp air more so passes through past the reg as appsoed to through?

-matt

[snoopay700]

They can handle a max of 125psi working pressure as listed on the website if I remember correctly. As far as LPR pressure, there is no difference in a a basic LPR versus most normal inline regs. The only difference is really the use of a small spring that is "weak" - meaning it can only allow a weak pressure to pass. So max LPR pressure is strictly dependent on the strength of the mainspring, and the pressures the seals are designed to hold.

On my personal pneumag, I use a palmers fatty inline regulator that was made to pass HP to the mag valve and LP through the rail.

That doesn't really suit what i wanted to hear, oh well. Maybe i'll have to develop my own threeway that can handle higher pressure or something, i'm sure i'll figure something out.

[Pneumagger]

That doesn't really suit what i wanted to hear, oh well. Maybe i'll have to develop my own threeway that can handle higher pressure or something, i'm sure i'll figure something out.

check clippard or mcmaster for other 3 ways. there are plenty that have much higher pressure ratings.

[snoopay700]

check clippard or mcmaster for other 3 ways. there are plenty that have much higher pressure ratings.

If you set them up the same way you would a normal msv-2 do you know if the the trigger pull would be as light?

[Pneumagger]

If you set them up the same way you would a normal msv-2 do you know if the the trigger pull would be as light?

nope. A 3-way designed for heavier pressures would have to have a balanced spool design so you could actually depress the button, and the oring glands would have to provide more "crush" to seal the pressure.

Odds are almost all higher rated valves will requires much more force. The MSV-2 gets away with a light force because it's not fully sealed and also uses leverage action.

[snoopay700]

nope. A 3-way designed for heavier pressures would have to have a balanced spool design so you could actually depress the button, and the oring glands would have to provide more "crush" to seal the pressure.

Odds are almost all higher rated valves will requires much more force. The MSV-2 gets away with a light force because it's not fully sealed and also uses leverage action.

Well i guess i'll have to make do with the pressures i have available.

[snoopay700]

Ok, now i need a formula, if anyoen can help me, i know there's one i just can't remember it. Anyway, if i have the volume of both the dump chamber and the barrel, and the psi of the dump chamber, how do i find what psi it would be in the barrel?

[Pneumagger]

Ok, now i need a formula, if anyoen can help me, i know there's one i just can't remember it. Anyway, if i have the volume of both the dump chamber and the barrel, and the psi of the dump chamber, how do i find what psi it would be in the barrel?

Assuming negligible pressure head losses, and a constant temperature transitions (both of which are probably poor assumptions),

P1V1=P2V2

where Pn describes the pressure at the nth state and Vn describes the Volume at the nth state. This should be an effective equation for quasi equilibrium dry air processes that are well clear of phase changes, use with caution.