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All Springer/NP/PCP Air Gun Discussion General => "Bob and Lloyds Workshop" => Topic started by: OTmachine on November 11, 2024, 09:01:16 AM
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Just some off the wall thinking, now that I am retired and finally have some time to work on our air guns. In my job experience, I had to rebuild a hydraulic nitrogen accumulator for a crane, pre-charged at 2300 psi. I was thinking that if I were to build a non-regulated PCP pressure tube with valve assembly with the accumulator in tandem, before the air pressure tube, using air in both, say charged to 3000 psi, would it double the push on the pellet?
TIA, Keith
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Nope, accumulators are used to smooth out pressure spikes, and to provide a minimum pressure.... If you had an accumulator filled to 3000 psi, it would not be compressed further unless the air pressure exceeded 3000 psi.... To increase the pressure in the system, the air in the reservoir would have to be above 3000 psi, which means the reservoir and accumulator would both have to be built to stand the higher pressure.... Think of them as working in parallel, not series....
Bob
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Thank you Bob!
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I’m not Bob, and not sure it’s relevant to your thinking, but the Umarex Origin is supposed to have a gas ram somewhere in the air tube. They claim it makes it easier to pump (rifle typically comes with a hand pump) and maybe some other benefits. Hasn’t seemed to cause any copycats.
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The Aspen has the pressurized chamber also. It does help to maintain a steady pressure. It was pressurized to 1850 PSI.
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Jon and Robert, Thank you for the replies.
I believe that adding an accumulator would definitely make the pumping easier. I just pick up ideas reading posts and wonder, “What if”. In this case, I was thinking of one person pushing an out-of-gas car and someone came along and helped. There would be twice the power to move the car, so it would move easier and faster, yet the two persons power would be about equal. Then, I have to get into surface area that the force is applied to and pressure in a system being equal throughout (?). But I was kind of thinking that if there were two individual systems, ( as in two persons), then that would not apply.
Anyhow, I was just thinking, however off-the-wall it may be. Thanks again for the input. I will have to look at the Origin and Aspen to better help my understanding.
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Jon and Robert, Thank you for the replies.
I believe that adding an accumulator would definitely make the pumping easier. I just pick up ideas reading posts and wonder, “What if”. In this case, I was thinking of one person pushing an out-of-gas car and someone came along and helped. There would be twice the power to move the car, so it would move easier and faster, yet the two persons power would be about equal. Then, I have to get into surface area that the force is applied to and pressure in a system being equal throughout (?). But I was kind of thinking that if there were two individual systems, ( as in two persons), then that would not apply.
Anyhow, I was just thinking, however off-the-wall it may be. Thanks again for the input. I will have to look at the Origin and Aspen to better help my understanding.
Finding a functioning Aspen will be the hard part!
Edward
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Jon and Robert, Thank you for the replies.
I believe that adding an accumulator would definitely make the pumping easier. I just pick up ideas reading posts and wonder, “What if”. In this case, I was thinking of one person pushing an out-of-gas car and someone came along and helped. There would be twice the power to move the car, so it would move easier and faster, yet the two persons power would be about equal. Then, I have to get into surface area that the force is applied to and pressure in a system being equal throughout (?). But I was kind of thinking that if there were two individual systems, ( as in two persons), then that would not apply.
Anyhow, I was just thinking, however off-the-wall it may be. Thanks again for the input. I will have to look at the Origin and Aspen to better help my understanding.
Finding a functioning Aspen will be the hard part!
Edward
It's sad that a $3-400 dollar gun can become a paper weight because of no parts support.
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Do you think that the Aspen could be reworked where it would be reliable?
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I think that I can “safely” do a proof of concept with a Chief that I have using the pressure tube with a piston, a drop block for the 1100 psi HPA tank with on/off that i have. And add a fill valve for the pressure tube after the on/off to allow me to fill to 1100 psi. Chrony the rifle with the 1100 psi charge. Then refill the tube to 1100 psi. Open the filled 1100 psi regulated bottle valve and Chrony for results. Have to go thru and reseal the Chief first, (I had just reworked the trigger).
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You do know that the umerx origin has the same air pressure tube system as the Aspen right? They're both made by Nova along with the avenger, liberty, and the freedom airguns.
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Robert, Thank you for that information! I will research them to get better understanding.
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Here is a design for a 2:1 pressure booster.... Click to enlarge....
(https://hosting.photobucket.com/3850df3c-b679-46ee-81eb-78df103b29a8/da469d34-b541-4920-93a7-c984d04bcafa.jpg) (https://hosting.photobucket.com/3850df3c-b679-46ee-81eb-78df103b29a8/da469d34-b541-4920-93a7-c984d04bcafa.jpg)
The only problem is that you have to vent the LP side of the piston to reset for the next shot, which basically wastes half the air.... The HP side is pressurized directly from the tank, through a check valve.... When the valve is turned to the fill position, 1100 psi air flows to push the piston to the right, increasing the pressure in the HP chamber.... If the LP side of the piston is twice the area of the HP side, and the volume remaining in the chamber for the shot is equal to the swept volume of the piston, the pressure doubles.... After the shot, the piston is still at the right, and the HP side comes back to 1100 psi through the check valve, so there is 1100 psi on both sides.... The valve is turned to seal off the LP chamber from the tank, and vent it to the atmosphere (wasting a lot of air) to allow it to reset to the left.... The valve is turned back to the fill position and forces the piston to compress the air in the HP side again for the next shot.... Travis and I spent a lot of time trying to figure out a way not to waste half the air each shot, and never did....
Bob
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Hi Bob, Thanks you for the diagram and the explanation! Seems to be along the same thoughts that I was having, (i.e. how to get more pressure to the projectile). I really appreciate your experience! I have several Air guns that have been on the back burner for some time. I like to tinker with mechanical objects, have some mechanical and machinist trade experience, and some machine tools, along with a nice climate controlled work space for small projects. I will think on this some more, as it is of interest to me. Maybe, some sort of equalization check valve in the 2:1 piston area to keep from having to dump the air.
Thank you again for the input.
Keith