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Too Much Friction

Discussion coninued in "semi auto firefly valve"

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#26 Dyxlesic

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Posted 13 February 2011 - 11:07 PM


*spoilers*
When i said hybriding the 2 valves together, it is litterly what i am doing. It is like cheesys, using hornet parts and a firefly shell and turret for a semi automatic valve, but it has been re-worked in order to work with a backpressure tank/QEV like atomatrons as apposed to a at2k tank like in cheesys. this way, it is simplified, there is no need for a 3rd seal, and no need for another mechanism to pull the pin on the tank. I hope that makes sense


I've been working on the exact same thing with a DTG. Only I've been having sealing issues with the stock hornet trigger tube, so I'm going back to my homemade brass tube trigger valve which seals perfectly without doubbleing up on the o-rings and reducing friction. Or at leas i thought I was untill Nerkum posted a youtube link of the clipard valve integrated into a magstrike operating a big salvo tank. nerkums cliffard valve He presented it on page 2 of Buffdaddys semi-auto salvo thread page 2 of Buffdaddys Semiauto Salvo. Now i'm just annoyed my nerfing budget is spent. This may be a good time for both of us to listen to Doom.

oh my gosh, thats exactly what im looking for. now that i see it working, it makes sense now. I plan to buy one of these, and would buy one immediently if shipping wasnt $25 on a $7 valve. Thank you so much. Doom, you are right, I just didnt have the comprehension of hardware parts to realize it. Thank you so much for saving me time in the future. my only 2 remaining questions are:
1. is with that with the valve nerkum used, would the amount of pressure required to push the button on the valve increase as the air pressure of the tank increased?
2. would a solid primary tank work as well as an air bladder, or would the change in pressure between each shot be too dramatic?
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#27 Doom

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Posted 13 February 2011 - 11:20 PM

1. is with that with the valve nerkum used, would the amount of pressure required to push the button on the valve increase as the air pressure of the tank increased?


Probably, but I don't anticipate it would increase much. For both of the DCVs I've used I have not noticed any differences in actuation force over the range of pressures I've tested, which go from 15ish psi up to perhaps 120 psi.

2. would a solid primary tank work as well as an air bladder, or would the change in pressure between each shot be too dramatic?


Maybe, depending on how it was implemented. I generally prefer hard tanks with regulators to bladders. I also generally prefer bladders to hard tanks without regulators.

I'm going to make another suggestion if you want to use a "bladder" too: Don't use "bladders". Use latex tubing (you can search McMaster-Carr for it). It's the same material, except that you don't need to cannibalize a blaster to use it. You can make the bladder as large or small as you want. Here's some more information about latex tubing: http://www.sscentral...memade/lrt.html
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#28 Dyxlesic

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Posted 14 February 2011 - 01:02 AM

1. is with that with the valve nerkum used, would the amount of pressure required to push the button on the valve increase as the air pressure of the tank increased?


Probably, but I don't anticipate it would increase much. For both of the DCVs I've used I have not noticed any differences in actuation force over the range of pressures I've tested, which go from 15ish psi up to perhaps 120 psi.

2. would a solid primary tank work as well as an air bladder, or would the change in pressure between each shot be too dramatic?


Maybe, depending on how it was implemented. I generally prefer hard tanks with regulators to bladders. I also generally prefer bladders to hard tanks without regulators.

I'm going to make another suggestion if you want to use a "bladder" too: Don't use "bladders". Use latex tubing (you can search McMaster-Carr for it). It's the same material, except that you don't need to cannibalize a blaster to use it. You can make the bladder as large or small as you want. Here's some more information about latex tubing: http://www.sscentral...memade/lrt.html

My bad. When I said "solid tank" I ment a PVC tank filled by a magstrike pump. Would there be much of a difference between using a PVC tank and a latex bladder?
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#29 snakerbot

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Posted 14 February 2011 - 01:02 PM

You will have a very high pressure drop-off rate with a hard tank. You'll end up with a powerful first shot, and every shot after that will keep getting weaker. Bladders contract when they have less air, so they maintain a more consistent pressure.
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#30 Dyxlesic

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Posted 14 February 2011 - 02:57 PM

You will have a very high pressure drop-off rate with a hard tank. You'll end up with a powerful first shot, and every shot after that will keep getting weaker. Bladders contract when they have less air, so they maintain a more consistent pressure.

Could I put something in the tank that would take up space, but contract when pressure is put into the tank. But re-expand when air pressure is reduced. It would put more pressure in the tank to eleminate dead space and keep constant pressure, if that makes sense. Like the opposite of a bladder, taking up space, and would crush under pressure, but re-expand when the pressure disappears.
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#31 Doom

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Posted 14 February 2011 - 05:22 PM

Dyxlesic, I'm not sure if you understood what I wrote. What I wrote did compare hard tanks (like PVC tanks) against bladders. There are many significant differences.

A few other things:

If you don't use a regulator, you can still make a hard tank (regardless of the material; this depends on geometry) with an acceptable pressure drop by making the tank very large such that a decrease in gas mass in the tank does not correspond to a significant decrease in pressure. There are several disadvantages to this. The tank would be very large. You also will have to precharge the tank so a certain minimum pressure.

If you do use a pressure regulator, you can then use a smaller tank at far higher pressures and have more consistent pressure than with a bladder. You seem to be unfamiliar with regulators, so I'd suggest looking for non-relieving regulators like the Clippard MAR-1NR and doing some Google searches on the topic.

There are many differences between solid tanks and latex tubing. I think I have detailed their differences, and whether or not these are advantages depends on what you want. For more information about latex tubing, I suggest reading the link I gave. I'll detail what I'd do in some generic situations.

If you need higher (30 psi and up) pressures, use a hard tank with a regulator.

If you need lower (30 psi and down) pressures and want to save some money by not having to use a regulator, use latex tubing. Be careful when choosing tubes (see the link I gave for why) and replace the tube when it is worn out.

If you need lower pressures but want to save some space or have significantly higher number of shots per full tank, use a higher pressure hard tank with a regulator.

Hard tanks without regulators should not be used.

As for other methods to keep pressure more consistent, you can use some sort of spring and piston assembly to keep pressure more constant. However, using a pressure regulator is a far simpler, smaller, and likely cheaper approach.
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#32 Dyxlesic

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Posted 15 February 2011 - 12:11 AM

Thanks doom. Sorry for my low hardware comprehension. I have done almost no work with external parts. again, I have 2 more questions:
1. Does a 6" long 2"PVC pipe tank filled by a magstrike pump feeding into a salvo tank count as "high pressure" in your description above (like I would need a regulator right on this right?)
2. Can a regulator be calibrated/ adjusted quickly? For example, I'm about to run around a corner into a hallway. I don't want to use too much air/hurt someone, so I turn it on low. But after I rush I have to run back into a really big open room, and want to shoot really far, and adjust the regulator so it has a higher psi. Can I do/find something like this?

If that didn't make sense, I could reword it for you.
Thank you all for all your help on this project. I think you guys are really gonna enjoy how this project is gonna turn out
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#33 k9turrent

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Posted 15 February 2011 - 12:32 AM

AT2k stuffed into a Tommy20

Posted Image

Rear loading cause I can.
Posted Image

Yes that was a propane tank you saw.
Posted Image


The tank runs at 60 PSI, Lasts for ~25 shots. Hits at least 90ft.


If you are gonna use a hard tank, use a bank of converted propane tanks. They are safer and also have a built in PRV that is set at ~250psi.

Source:
http://usersites.hor...aneAirTank.html
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That's about it. And thanks Angela who helped me with these pictures.. It looks huge in her hands.


HOLY CRAP!

FU ALL

#34 shmmee

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Posted 15 February 2011 - 08:35 AM

Clippard has a distributor locally to me in slc. I'll see if the MAVO-3P is any cheaper through them. Maybe i'll only have to donate plasma instead of sell a kidney... (They seem to have distributors nearly every where.) At the least it will probably be next month before i have any fun money. 12$ shipping and 10$ handeling for a 8$ valve? Really?

If it is substantially cheaper I can order a second one for you Dyxlesic.
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#35 Doom

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Posted 15 February 2011 - 12:35 PM

Dyxlesic, don't worry about asking too many questions. This is one way to learn.

1. Does a 6" long 2"PVC pipe tank filled by a magstrike pump feeding into a salvo tank count as "high pressure" in your description above (like I would need a regulator right on this right?)


Volume is not pressure. So what you described does not necessarily count as "high pressure", but it could. What pressure do you intend to fill the tank to? I had the approximate ranges set very clearly.

A 2" diameter 6" long tank is a moderate size in my experience and (if you use pressure rated fittings) you would do very well to charge it to about 120 psi. That would be "high pressure" as far as I'm concerned.

I should note that I don't suggest using PVC pipe for compressed gas unless the pressure will be applied only intermittently (i.e. for less than a second or so). I understand not using PVC is not an option for many people. I'm working on alternative methods for gas reservoirs. Converted propane tanks are one option, however, I think they are too heavy for most people. If you can find lightweight aluminum tanks, that'd be great too, but unfortunately they're very hard to come by.

2. Can a regulator be calibrated/ adjusted quickly? For example, I'm about to run around a corner into a hallway. I don't want to use too much air/hurt someone, so I turn it on low. But after I rush I have to run back into a really big open room, and want to shoot really far, and adjust the regulator so it has a higher psi. Can I do/find something like this?


This depends on the regulator. Some intentionally can not be adjusted (mainly to prevent tampering or because it's a high precision regulator), but I am yet to see any Nerfer rob themself of that opportunity for the reasons you've described. Most (as does the one from Clippard I recommended) have a knob you can turn and a nut you can tighten to lock the pressure if you don't want to adjust it too easily after that.

You'll need a pressure gauge on the outlet to see what pressure you're regulating at (some regulators have this built in and some others don't). You'll also need to understand that once the pressure is on the other side, reducing the pressure of the regulator won't magically reduce the pressure on the outlet (unless the outlet pressure somehow is higher than the inlet pressure and there is no check valve so that the flow can go backwards through the regulator, which can happen if you make it do that, but that's not a typical situation). You'll need to reduce pressure, fire to exhaust the outlet side, and then see the outlet pressure equilibrate to the new set pressure.

Clippard distributors are way more reasonable than ordering from Clippard themselves for the mentioned reasons. Group orders would be great to save on costs even more. Be aware that sometimes the distributor has to order the parts themself from Clippard and you could have to wait up to a month to get the part. I think the wait is worthwhile, but I work very slowly due to other commitments, so I'm not like most people.

Edited by Doom, 15 February 2011 - 12:35 PM.

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#36 Dyxlesic

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Posted 15 February 2011 - 12:49 PM

Clippard has a distributor locally to me in slc. I'll see if the MAVO-3P is any cheaper through them. Maybe i'll only have to donate plasma instead of sell a kidney... (They seem to have distributors nearly every where.) At the least it will probably be next month before i have any fun money. 12$ shipping and 10$ handeling for a 8$ valve? Really?

If it is substantially cheaper I can order a second one for you Dyxlesic.

That would be fantastic. If you find a regulator that can be quickly set to designated pressures, like what I mentioned above, get one of those too for me. I don't know what the 2nd piece I'm looking for is, but I know what I want it to do; regulate, and be adjustable to a desired pressure quickly

I thought about using a fire extinguisher, but I need output holes in specific locations, it is (almost) internal, and needs to be a specific shape and size, and is only going to be filled by a magstrike pump, so it wont need to withstand crazy high pressures

I have given up on keeping this project secret, as I realize in order to get the best information on what I am looking for, I will need to show exactly what I'm doing. I will post a detailed diagram of my plans. I know EXACTLY what I'm trying to do, I just don't know much about manufactured parts. I will post it as soon as I can, either here or as a new thread. (im not sure which would be more appropriate). Again, thanks to everyone so far, and help to come. All ideas are welcome

Doom
I saw the turnable dial screw on top of the regulators you sent to me. I looked into information on regulators, so I have a general idea on how they work and what they do. I realize if I adjusted the regulator, I realize it would not adjust the pressure of the current air tank, but it would adjust the pressure of the second shot after adjustment. I don't know what a "relieving regulator" is, but I'm guessing it acts as an overpressure valve on the output side, and the overpressure valve would be calibrated to the same pressure as the regulator is, but I may be completely wrong. Is there a valve where you turn like a volume nob on a speaker, where I could label (or it could be pre labeled) it and quickly turn it to different spots like the rapid fire 20 (but air pressure as opposed to speed) to control how much Power I want the dart to have?

Edited by Dyxlesic, 15 February 2011 - 02:09 PM.

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#37 Doom

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Posted 15 February 2011 - 04:19 PM

A non-relieving regulator is the closest thing to what you want.

The dial does adjust the pressure of the current shot. However, as I said, if you want to decrease the pressure in the chamber, you have to exhaust the tank first. The extra gas in the chamber has to go somewhere. It can't just magically disappear. So you can increase the pressure on the fly by turning the knob (this adds gas to the chamber), but you can't decrease it without evacuating the chamber in some fashion (i.e. the gas can't just magically disappear, and it can't flow back through the regulator unless the pressure on the inlet of the regulator is lower than the outlet pressure, which defeats the purpose of the regulator).

There is nothing precisely like what you want as far as I know, but a non-relieving regulator is the closest thing. You probably can make a new valve to do what you want (i.e. exhaust the outlet chamber until it reaches the set pressure if the outlet chamber has too high a pressure), but that's way more complicated than what you started to do.
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#38 Dyxlesic

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Posted 15 February 2011 - 06:17 PM

So correct me if I'm wrong:
If I increase the pressure on the regulator, the pressure on the output end will (almost) instantly adjust to be the pressure that I set on the regulator
If I decrease the pressure setting on the regulator, the air will not instantly decrease, because the air has already passed the regulator, and regulators do not have a built-in release valve. (because in order for that to work, the OPV would have to adjust itself at the exact same rate of the regulator, which would be a pretty complicated mechanicism)

This question has nothing to do with the above question, and am not worrying about that problem with this specific scenario
My question is are there regulators where I can draw a pointer on the dial, and when it is (just a random example) turned to point A on the far left side for low pressure (ie. 10 psi), or point b on the far right side for high pressure (ie. 30 psi) or have it anywhere in-between. This would allow me to know how much psi im putting in
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