I HAVE A IDEA!

[enazle]

I use a 6000psi nitrogen to fill with which is great until I get down to 3500psi.  The place I was getting cylinders went up 50% to over a $100 per refill and $60 year rental. I have an idea of getting a YH compressor and pipe the Nitrogen to the intake side so I can use the remaining gas to fill my pony tanks with? Is that possible with these little compressors? I know moisture seems to be a issue and this would eliminate it? It's a 5th the cost of a booster.

[tracker1955]

You would have to have a way to regulate the pressure down to maybe 10psi or less or you may over pressurize the first stage cylinder. You don't want to blow the cover off the oil reservoir.

[AlanMcD]

Agree -and you will have a hard time finding a regulator that will take 3500 psi all the way down to less than 10 (and I think you need to be down around 2 or less to really get it to work right).

A better option would be a regulator and a booster pump.  And if you have access to a shop compressor to power the booster, you can use almost all of the nitrogen for shooting.

[enazle]

So can you explain why the psi has to be 1 or 2?  I understand the first stage pressure would increase.  Is there anything in the literature that says what the ratio is? Is it an exponential relationship?  I know my bottle reg will reduce to 200psi and I can put a HF reg behind it to take it down from there.  But then I'm not sure that will be enough CFM to run the compressor?   

[Rob M]

even at 29 psi input, your putting twice the work load on the motor making the first turn. ( lets assume atm is 14.5 where you are )

Seeing as how these compressors can barely handle the intended input , this idea would blow the YH motor , seals , etc in rapid succession

the motors current wattage was intended to push the piston at roughly atm pressure.. asking more of it is the same as putting an 500 lb man on a home treadmill. ( its actually worse since the treadmill is already moving

[tracker1955]

I'd also be concerned that the incoming pressure would hold the incoming check valve open and it won't seal to cause compression.

[enazle]

I would think it would have as much to do with how much air passes through in cfm?  It's creating negative pressure during the suction cycle? I wonder if the factory will answer a question? Good discussion.

[AlanMcD]

I had said "under 2 psi" because when we are working with things that are meant to run at atmoshpheric pressure, 2 psi is a massive amount of pressure - at that level, you would be feeding at least 14% more air charge into the cylinder than it was used to.  Another way to think about it is this: how long would your compressor work before breaking if you were able to "make a modification" that increased the first stage compression ratio by 14%?  Given that these compressor seem to be hanging together by a thread to start with . . . I doubt it would last very long.

Another way to think about it is to think in the measurement of pressure for low pressure operation, like furnaces and water heaters on natural gas - the measurement here (at least in the US) is known as inches of water column (literally how many inches a column of water would be blown up a pipe if the surface of the water outside the pipe was exposed to pressure and the top of the pipe was open to the atmosphere).  The pressure of the lines inside our houses are usually running at about 7-8" WC, and the manifolds in our furnaces are around 4" WC.  2 PSI translates to about 55" WC.  Imagine that flow rate as a comparison . . . . FWIW, that is more like the pressure in the gas lines before getting down regulated into our houses.

[Taso1000]

Hey Enazle,

A Shoebox compressor would work in this situation as long as you fed it at 125 psi.

Taso

[Rob M]

Hey Enazle,

A Shoebox compressor would work in this situation as long as you fed it at 125 psi.

Taso

THIS !

[AlanMcD]

I agree as well- of course you would have to find a used one, which is why I suggested a booster.  It a Shoebox would be ideal, with no wasted nitrogen being used to power it.

[Taso1000]

An Altaros compressor could be used if you had a big enough air compressor to run it.  You would have to split and feed its two air systems separately to not waste nitrogen needlessly.  One system runs the compressor and the other is to feed what you want to compress, nitrogen in this situation.

Altaros has instructions and a kit to do this.  Their tech support is very helpful.

This suggestion is not the best solution as I think powering a compressor with air is very inefficient.  But if you have more compressed air than you know what to do with, the Altaros can be made to boost nitrogen.

Taso

 

[enazle]

So I did a little research. The material on Alibaba says it uses 50l per minute. Based on Google lol And this website https://www.greenlinehose.com/content/Hose%20Flow%20&%20Sizing.pdf I would need about 30psi in a 1/8" microbore to generate 2 scfm (Standard Cubic Feet Minute) which equates to 56 liters per minute. What I don't know is how that relates to nitrogen?

[Killfire]

Couple years ago I tried to feed my single cylinder tuxing. It didnt work out well at all. Had to be 5 psi or lower and fill times greatly increased.

[RogerB]

Hi Enazle,
I recently set up a YH compressor to boost nitrogen from a 2400 psi tank.  I used an input pressure of approximately 15 psi.  Chose 15 psi because I’ve read where guys use a 20 psi boost for hand pumps to speed up pumping.

A tricky part for me is regulating the input pressure.  You set the regulator at 15 psi and as soon as you start the YH the pressure goes to vacuum.  I’m feeding the nitrogen to the YH through a regular air line hose, not microbore, so you’ll have even less “plenum” volume.  I have large low range pressure and vacuum gauges in the line going to the YH so I can see where I am.

Getting the input fitting to the YH was a bit of pain for me.  The thread is metric, kind of loose, and the space is crowded where the intake filter is.

Fill times seemed OK, didn't measure them.  I’d expect the fill time to be about ½ normal at 15 psig input.

I’ve only run the system twice, topped off a small buddy bottle to 4500 psi and a 44 cu-ft SCBA tank to 4300 psi.  No real history here with the YH, but I have been feeding a SW flame thrower compressor with nitrogen for a couple of years now with no problem.

Roger Barker
Middlefield, Ohio

[Chickenthief]

The Altaros can be configured in several ways.
1) Normal where a shop compressor feeds the big piston as well as the booster pistons.
2) Then you can "rewire" so the big piston is fed from a shop compressor and then the LP and HP pistons is fed a gas with an input pressure of no more than 10bar~145psi.
3) Lastly where the big piston is fed from a shop compressor and only the HP piston is fed gas at a pressure of 80-100bar~1100-1450psi.

I have mine hooked to a 1hp shop compressor and it fills to past 300bar~4500psi just fine, slow yes but it just chugs along.

Normal Nitrogen regulators can regulate down to 0psi no problem.
In order to get the compressor to work properly you need a tank the size of several gallons with regulated gas so it can not so good as much as it needs not just as much as the regulator will deliver (that will starve the compressor).

[enazle]

Everything boils down to a money game.  I get maybe 2 tanks a year and use them down to 3500 psi.  That's $240 a year plus the $60 rental.  I can't justify $1600 to save $120 a year from buying a booster. I might consider spending $300 under the condition I can use the Nitrogen because it is high purity and lack of moisture.  I guess this all hinges on learning the intake port thread specification and being able to buy a thread adapter the right size? Using Microbore hose and fittings enables the psi to be high enough for the regulator to work while providing enough gas to run. 

[RogerB]

Enazle,

Here are a few more details about my experience setting up the Yong Heng to feed nitrogen.  The thread for the input filter is M12-1.25mm.  Below is photo of what I did.  What you’re looking at is a metric bolt with the M12 thread.  The head was cut off and the bolt bored out to allow the nitrogen to flow through the bolt.  I added a jam nut to add rigidity and possibly help seal. Next in line is a M12 coupling nut, then an M12 to ¼”npt adapter, and finally a ¼” standard air line, male, quick disconnect.  Not an elegant solution at all, but it works.  Concerns / issues are:

1.   The inlet thread is a little loose.  I used about 10 raps of Teflon tape and added the jam nut threads on the bolt into inlet threads.  The jam nut also added stability.  Not sure this helped much with the seal, but it definitely added stability.  I’m thinking the seal for this connection is not that critical in that it sees relatively low pressure, target of about 15 psi.

2.   The M12 bolt is very close, touching, the 1st stage condensing block.  I actually filed down the threads some in the central section of the bolt where it was resting against condensing block.  I didn’t want the threads biting into the block during operation where there is quite a bit of vibration.

3.   As I mention earlier, when you start the compressor the pressure drops immediately.  When I start the compressor my other hand is on the regulator to increase the pressure back to about 15psi.  My first reaction was to overdo the pressure so I added gauges to make it easy see where I was on this.  Below is a photo of the gauges I added.
So, Enazle, this is what I did and, it works for me.  Adapting this to a Foster type quick disconnect wouldn’t be difficult.  You might want to consider one of the other inexpensive Chinese compressors.  I saw on YouTube where a guy had altered the input port so the incoming air would be pulled through a tube of desiccant. He was using a Tuxing compressor.  The video looked like access to the input port on the Tuxing was less obstructed.  I chose the YH because it seems to be the most popular.

I just looked here’s the link for the YouTube link for the guy who modified the Tuxing:



Hope this helps,

Roger Barker
Middlefield, Ohio

[MJP]

Well I just can't figure this out, buying a compressor and using nitrogen. There is a huge used market for industrial booster pumps in the USA and you buy cheap Chinese compressor to feed the nitrogen to a tank.

I bought a Haskell booster from the US shipped to Finland for less that 300€ an it will run for ever. I have made a simple booster that works for boosting nitrogen for bottles. That is what I started this hobby with.

Stop being so narrow minded and look outside the box, there is more options than just cheap YH from china. Look from other sources than airgun equipment.

Marko

[enazle]

Marco, which model Haskel booster did you use.  I haven’t seen anything less than $1000?