Basic Vertecon 13cfm questions...

[geko21]

I am playing with a new Bauer Vertecon 13 compressor and although most of the things are clear there are still a few points I can not figure out, and the manual is not very helpful.

The unit is set for 6000psi. However I will be filling to only 3200psi and will not be using banks. It is a basic compressor-4way Maniford setup. I can set the unit to shut down at 3200 through the electronic control unit but this would mean that it will stop the motor every time the four current tanks are filled and it will start again with the next set of tanks. I want to avoid the constant stop/start cycles.

What I need to do is set a valve to blow at 3200psi so that we can change tanks without the compressor shutting down - and basically eliminating the possibility of the unit ever reaching near 6000, and thus also avoiding possible tank blow up. How can I do that? I am aware that I may be missing something very basic. Any advice will be highly appreciated.

 

[Tbar]

Why not use it the way it is set-up and others use there's it stops when the tanks are full. You do not need to be 'manning' the compressor the whole time.

What do you see as the issue with the 'start cycle' vs the benefit of it running and bleeding air?

 

[geko21]

Why not use it the way it is set-up and others use there's it stops when the tanks are full. You do not need to be 'manning' the compressor the whole time.

What do you see as the issue with the 'start cycle' vs the benefit of it running and bleeding air?

I am filling EAN 32 with a Nitrox Stick. If I have to fill 12 tanks, it takes me 1 minute to take out the four full tanks and to put on the next empty batch. It makes no sense to me for the compressor to stop and start during this, and it also complicates the oxygen flow operation at the nitrox stick end, which also has to be cut out then the compressor stops. Having the compressor cycle on and off all the time does not make sense on any front and it shortens the life of the whole system.

 

[Namreg 58]

If your fill manifold has four fill valves, you can simply just fill two tanks at a time while the other two are on standby. When two are full, close the valves and open the next two valves so that while these are filling, you can remove the full ones and attach the next two.

I would advise putting them in a water bath as at 13 cfm fill rate, they would get pretty hot in around ten minutes .

You should have a manual/auto override switch to bypass the auto pressure shutdown.

 

[tbone1004]

with a 13cfm compressor only filling small tanks like that I would invest in at least 2 bank bottles if anything to take up the slack when you are changing tanks. The other option would be to to change your manifold setup to a valved manifold where you can stagger the bottles going through. Your pressures are determined by the compression ratios in the pistons so you don't have the ability to just change the output pressure on a compressor. 13cfm is pretty quick, so again would be better for everything involved to either have a set of high pressure pipes going through a water bath to cool them off a la intercooler type setup, or again, get some bank bottles to help slow the filling down.

 

[CraigAClark]

Install a good quality, high volume venting safety on the manifold inlet port.

 

[ti325v]

with a 13cfm compressor only filling small tanks like that I would invest in at least 2 bank bottles if anything to take up the slack when you are changing tanks. The other option would be to to change your manifold setup to a valved manifold where you can stagger the bottles going through. Your pressures are determined by the compression ratios in the pistons so you don't have the ability to just change the output pressure on a compressor. 13cfm is pretty quick, so again would be better for everything involved to either have a set of high pressure pipes going through a water bath to cool them off a la intercooler type setup, or again, get some bank bottles to help slow the filling down.

I have a k-14 pumping about 13 CFM, I have a 4 whip manifold. Sounds similar to the O.P.`s set up.
A very important aside... PMV`s generally have have a large slack point between when they open and the pressure they maintain. Most I have used and currently use, will crack at about 210 BAR, (Depending on set point) then hold 140 BAR in the filters. That was a little low for me. I wanted 180 in the filters, which would require me to risk over filling he tanks if I got lazy and missed a tank swap.
The simple solution to this problem....a second OPV at the manifold.
Primary OPV at the filter set to 250 BAR to keep my filters at 180 BAR, which makes the PMV crack at about 250 BAR.
Once the air goes through the filtration and on to the tanks, (Which I only want at 200 BAR) the tanks fill to 200 then blow the opv at the manifold.
One OPV $75, and problem solved. A couple of 6,000 psi bottles over $1,000.

To address the above
1) Water baths are big No-No, Suggest a bit of research.
2) My tanks never get more then warm when filled. Standing on the floor. (4X12 liter Al at a time)
3) Air temperature coming into the tanks has nearly no effect on fill temperature. the place for the cooling coil is before the final separator.
Adiabatic compression is heating the air and air is heating the tanks.
If you do not believe me, feel the actual tank valve when you are filling, it is cool, even when the tank is hot, as the air expanding into the tank is dropping the temperature of the valve.

 

[tbone1004]

I agree with you, but if you're going to have a water cooling system I'd be cooling the air before it gets to filtration, and I agree it will have essentially no effect on the tank temperatures. If I were designing a compressor each of the cooling coils between the stages would be run through water to help keep the compressor as cool as possible.

 

[ti325v]

I agree with you, but if you're going to have a water cooling system I'd be cooling the air before it gets to filtration, and I agree it will have essentially no effect on the tank temperatures. If I were designing a compressor each of the cooling coils between the stages would be run through water to help keep the compressor as cool as possible.

I detailed how all of my compressors are set up....and it is with the cooling coil BEFORE the SEPARATOR. Putting it in front of the filtration is useless as far as I have been able to determine, the only possible benefit would be to help the M.S. to work at a lower temperature. A properly set up compressor should never be exceeding the temperature that M.S. looses effectiveness, (as I understand it about 140*f.)
Separator inlet temperature should not exceed ambient plus 30*C, with massive gains in filtration effectiveness under higher pressure and lower temperature.
How do I know ?.... I fill over 1,500 tanks on 1 KG of m.s. in the tropics. still under 10% R.H. at 200 BAR.

---------- Post added March 26th, 2015 at 06:29 AM ----------

I agree with you, but if you're going to have a water cooling system I'd be cooling the air before it gets to filtration, and I agree it will have essentially no effect on the tank temperatures. If I were designing a compressor each of the cooling coils between the stages would be run through water to help keep the compressor as cool as possible.

There is a company that does water cooled heads for k-15`s and possibly k-14`s, nice in a place you cannot get enough ventilation, but not necessary in the vast majority of conditions. Big money for no gain if you set up properly and monitor head temperatures and buy the right compressor for the job. Most 7-10 cfm pumps are a little too small to cool well in the tropics at high revs. Oversize it at purchase and down rate it a bit if its gonna be really hot, especially if blending nitrox, same result, less cost and hassle.
My four cylinder k-14 runs cooler at 1500 rpm then my 3 cylinder mch 16 at 1300. More metal, better fan design, more interstage cooling.

 

[geko21]

Thanks to all who took time to answer, it is really appreciated.

One thing I still do not understand... Why not just adjust the venting pressure of the PMV just before the manifold to 240bar, which is what I fill my tanks to anyway? This is the picture of the thing:



Then I can set the software cut-out pressure to 250 and it will trigger only in the event of a valve failure. In my logic, which may be flawed, this simple thing will solve the problem and the compressor can never pressurize to more than 250bar. When the tanks get to 240 the valve will blow, but the compressor will not stop. Is there something wrong with this? And if that is OK, is this type of pressure valve easy/precise to adjust (it is a little bit different than the one on the older Bauer models)?