Brand new HP100 air fills

[boulderjohn]

This shouldn’t happen, fill it at a reasonable rate to 3200 then.

I agree. In the case of the shop where I worked, there is virtually no local diving, so almost every tank they filled was for us in beginning instruction in a swimming pool, so 2,800 was enough.

 

[divezonescuba]

From a shop perspective.

we run all tanks directly from the compressor with multiple whips. We do not use a bank system.

we fill AL80s to 3250 from the compressor. They cool down to about 3000-3050.

To fill Hp tanks, we have to run the compressor to 3600, let the tanks cool for a couple of hours, and then run them up again to 3600. This cools to 3450. Steels can become very hot during the compression process hence the requirement to cool for a significant period of time. We tell people that upfront, that they probably won’t want to stay for the fill.

Because of the extra handling required, we charge extra for HP fills. However, we are happy to run HP tanks the same way as AL tanks for the same price as an AL fill, if they don’t want to pay the extra few dollars.

We haven’t had any complaints with this policy.

 

[boulderjohn]

From a shop perspective.

we run all tanks directly from the compressor with multiple whips. We do not use a bank system.

we fill AL80s to 3250 from the compressor. They cool down to about 3000-3050.

To fill Hp tanks, we have to run the compressor to 3600, let the tanks cool for a couple of hours, and then run them up again to 3600. This cools to 3450. Steels can become very hot during the compression process hence the requirement to cool for a significant period of time. We tell people that upfront, that they probably won’t want to stay for the fill.

Because of the extra handling required, we charge extra for HP fills. However, we are happy to run HP tanks the same way as AL tanks for the same price as an AL fill, if they don’t want to pay the extra few dollars.

We haven’t had any complaints with this policy.

I will confirm from my own experience filling HP tanks that it is very hard to get a fill at the rated capacity.

 

[shurite7]

Here is a chart I made up for local dive shop. You can get a pretty good idea of temp effects on fill pressure.

The chart is nice, but what about temps below 70 degrees. For six to eight months out of the year I was filling tanks in temps that ranged from 10s to 50s. I placed a space heater in the compressor room (it was not a heated) to bring the ambient team to high 30 before filling.

To make sure tanks were filled to capacity I asked the customers to leave the tanks over night or drop them off in the morning and pick them up in the afternoon. During the winter I’ve seen tanks that remained in the compressor room over night drop as much as 600 psi.

 

[apenland01]

From a shop perspective.

we run all tanks directly from the compressor with multiple whips. We do not use a bank system.

we fill AL80s to 3250 from the compressor. They cool down to about 3000-3050.

To fill Hp tanks, we have to run the compressor to 3600, let the tanks cool for a couple of hours, and then run them up again to 3600. This cools to 3450. Steels can become very hot during the compression process hence the requirement to cool for a significant period of time. We tell people that upfront, that they probably won’t want to stay for the fill.

Because of the extra handling required, we charge extra for HP fills. However, we are happy to run HP tanks the same way as AL tanks for the same price as an AL fill, if they don’t want to pay the extra few dollars.

We haven’t had any complaints with this policy.

Yes, these were filled from a bank, but I think the issue was maybe they limit fills to 3000, as both tanks were the same. I'll have to ask next time I get a fill in a couple of weeks if they do HP fills. I paid the same price for the fill as I did for my Norris LP 72....

 

[bletso]

I just ran the numbers from the legal fill temp. i.e Al80 is 80 cf @ 68 ° F Most shops fill in a heated environment. I just ran some numbers from 40 to 90 F. It is an excel spread sheet. If you fill at 50° you fill to a lower pressure and when the cyl heats up to 70° it will be the rated volume/pressure.

 

[divezonescuba]

I have been meaning to ask.

AL80s of even the same manufacturer and close manufacturing date appear to have different surface temperatures when filled from the same manifold at the same time.

I havent used an infrared thermometer, but have noticed a significant difference.

any hypotheses?

 

[p_kos]

From a shop perspective.

we run all tanks directly from the compressor with multiple whips. We do not use a bank system.

we fill AL80s to 3250 from the compressor. They cool down to about 3000-3050.

To fill Hp tanks, we have to run the compressor to 3600, let the tanks cool for a couple of hours, and then run them up again to 3600. This cools to 3450. Steels can become very hot during the compression process hence the requirement to cool for a significant period of time. We tell people that upfront, that they probably won’t want to stay for the fill.

Because of the extra handling required, we charge extra for HP fills. However, we are happy to run HP tanks the same way as AL tanks for the same price as an AL fill, if they don’t want to pay the extra few dollars.

We haven’t had any complaints with this policy.[/QUOTE
I’ve never heard of charging extra for HP fills. It’s BS and I would certainly not get a fill there again.

 

[p_kos]

Charging extra for HP fills is BS, I’ve never heard of this happening and would certainly not come back to a shop that was this chintzy.

 

[divezonescuba]

Thank you.