Two bottle cascade vs direct filling

[Graeme Tolton]

I did forget to mention about continuous dute. It is not necessarly keeping the block cool, the little intermitten duty compressors are lacking in the interstage cooler department. I wouldnt bother buying anything that is not continuous duty.

So, with the compressor in a refrigerated truck box, to be cold inside, the diesel engine must be running outside. Keeping on top of it, making sure the intake is upwind may be a tiring task. I would recomend an inline co monitor and a hopcalyte bed in the filter.

There are co monitors on the market that incorporate a relay that can shut down the compressor. This would be the safest bet.

 

[BackwoodsGA]

I will be running all single phase 220v. Right now I am looking at a Capitano or an American Bristol with 5HP motors.

 

[Graeme Tolton]

Is there no diesel on the truck body?

 

[KD8NPB]

You should probably have 2:1 or 3:1 ratio as many LP as you do HP for a cascade.

We have about a 5:1 ratio. It's invaluable for whenever the Sheriff's department comes in and says "Yeah, here's 30 tanks. Please fill them. We'll wait."

 

[BackwoodsGA]

No, old milk truck with modern compressor and evaporator system. Cooling system in 220v 20A on another circuit.

 

[Graeme Tolton]

Ok, all is well. Good idea to do a fair amount of research on filtration as well. Filter should have some hopcalyte in it either way.

Good luck, keep us posted.

 

[rcontrera]

I would like to add a little on the small compressors. I don't know about any other brands, but the small Bauer Jr II, Oceanus and Coltri MCH6 compressors are not rated for continuous duty. In order to keep the weight and price down, they economize on the crank shaft and bearings so they are not really meant to pump up bulk bottles.

It isn't really the temperature that is the main concern ... although it is important. The main worry is the time at sustained load. When pumping up a single scuba or SCBA bottle to pressure, it is only at the max pressure for a short period of time and then the pressure drops back down again to fill the next bottle. When pumping up a large bulk bottle, it sits at some pretty stiff pressures for a long time and you can almost hear the compressor eating itself until the bulk bottles are full.

Go with the larger, continuous duty compressor and add a tall filter stack (or two) before feeding your cascade.

Just my $.02

 

[frogman62]

IF you are looking to spend a lower amount of cash for a continuous duty HP compressor, consider the Bristol 4S7-70 I have on my website. These were used by fire departments for many years to fill cascade systems - keeping them topped off at 4500-5000PSI. They seldom ran at pressure below 3000PSI and filling 6 - 440 cu ft storage tanks from 3000 to 5000PSI was a 3-4 hour continuous running task. I can put any size filter you want on the system - even to give OSA if you need it. System is compatible with nitrox stick for continuous blending.
Jim Shelden
316-992-0505
sheldensportinggoods.com

 

[BackwoodsGA]

If I can use two whips and fill my tanks in pairs it will be fast enough for me. I only dive everyother weekend so no big hurry. Was worried about partial pressure filling from the compressor, maybe a hyperfilter would take any worry out of that.

 

[Doc Harry]

I have a 3 cfm compressor and three 4500 bottles in a cascade system at 4,500 p.s.i.

You can't fill very many cylinders from a cascade system that small before the pressure drops way off. It would be even more limited with only two bottles in the cascade.

I have found that the only time I really use my cascade is late in the evening when I want to refill a few cylinders without waking the neighbors with the compressor.