Nitrogene tank

[JeanFreli]

We have a 2000 liters tank. Twice in a short time we completely empty it. So we had to switch to the emergency bottle by the time they came to refill. In the same time the quality of the piece we cut were so so. Would like to known if emptying the tank can produce some humidity or bad quality gas in the line or others effects somewhere.
And does some of you have a generator to produce the azote? Is that true that the system can be paid back in 2 or 3 years. I mean paid back compare to the cost of the transport of the gas, the renting tank etc....

 

[LASERNINJA]

A few things. There is a pressure relief valve on the machine. Sometimes they get stuck open and can bleed off the remaining volume in the tank. I would investigate that.

Second, I have seen this once. One of my customers had a not so good nitrogen generator tied together with their bulk tank. When the bulk tank got too low, the not so pure nitrogen from the not so good generator contaminated the bulk tank and caused poor cut quality. A strange situation.

Last, It depends on the machine type and what you cut to determine the "return on investment" of a generator. I do not sell generators. I do not benefit from them. My understanding is most people spend around $2000 a month for nitrogen. A good nitrogen generator cost around $100,000 maybe a bit more. That is about four years to pay for its self. There is a lot more too it but that gives you and idea. During that four years you can either send $2000 to the gas company or $2000 to the bank to pay for your generator. Whats the difference?

 

[JeanFreli]

Well thanks for the answer. Yes we had the valve stuck. With hot water we fix it but still working on it. The company who rent may change it.
But from what I understand it is possible that the purity may change a bit.
For the generator it seem to be realist that the system can be pay back in four years. It is after the four years you do not have to pay $2000 to the gas company. But still it is a big amount of money to start.
I'm curious about that subject,reason number two, because we are preparing the entrance of our new fiberlaser 4kw with 23 foot table. It is a pretty big machine and the speed should be double. So I presume the consumption is a lot more. The tech told me it is suppose to use 23% less than the 2kw.

 

[Foostrap]

The gas flow should be about the same for a 2kW or 4kW. The flow will change based on the cutting pressure and the nozzle size used. Assuming you use the same on both machines, flow will be the same. However, you will be cutting much faster on a 4kW fiber compared to 2. Therefore you will use less gas to produce the same part.

Regarding the N2 generator, the price will depend on the pressure, flow and purity required. Depending on your production, you need to decide what maximum thickness you will cut using the generator. The price goes up very quickly based on pressure and flow (with same purity). So if 90% of your production is thin material, you could get away with a smaller, cheaper unit. And use liquid N2 for the thicker plates. Best is to talk to a N2 generator sales rep; he should be able to help dimension and price the correct unit for your needs.

 

[JeanFreli]

I agree with you.
From what I see we will cut thick pieces and often very long (20 feet).
I don't known if it is normal but the guys who sell that machine use a lot of pressure to cut. They push very hard. They use an average of 15 to 22 bar for ss 12 gage to .250 inch. They told me and I cote (fiberlaser always high pressure). I did the same and often better with less. I'm from 11 to 18 bar. It seem CO2 use less. There is a big difference on the tank because I use 25% less gas.
First is there somebody who used 22 bar to cut ss .250? To compare, how much do you need for the same thickness on a CO2 machine?
Thanks

 

[RPosty]

Also inquire on the maintenance costs of the nitrogen generator of that size. We have a small beam purge unit which requires periodic maintenance every 5000 hours and a bigger one at 10,000 hours. the 5000 hour kit is about $900, and the 10,000 desiccant change is about $2500 and this is a small unit. Our unit also requires 90 PSI of very dry air which incurs costs too from our Kaeser Air Compressor which also needs to be maintained. I am not familiar with the bigger units, I assume they are stand alone and do not require additional equipment, but it is worth asking.

"I am stuck on Band-Aid brand, 'cause they are stuck on me"