Do I want a compressor?

[Schwob]

Good point on not slowing down a compressor...unless you really know what you are doing. And I admit that at this point that I am still a compressor idiot trying to slowly "de-idiotize"...

 

[JamesBon92007]

Looks tiny. Which makes it interesting.

It will run from a 15 amp circuit and, according to what I read on SouthWest's site, I could even crate it and take in with me on the airplane.

 

[JamesBon92007]

I have HP cylinders and HP twinsets and have concluded that the smaller portable units will overheat and suffer early failures for that kind of service, so the right size for me is probably one of the four-stage machines in the 8-10 scfm range. A slightly larger machine would be OK if it would run on single phase electrical power. I'm pretty sure that, if I proceed with this, I don't want a gas or diesel fueled machine.




That is similar to the flamethrower compressors of the era (and may have been manufactured for that service).

JamesBon92007, I hope you have filter towers for that -- there aren't any in the photo. I've encountered old divers who used flamethrower compressors without any filtration for shallow freshwater dives. People get away with it because the CO is not as serious a risk in the shallows and by letting the cylinders sit after filling most of the water and oils condense out. Not good for the cylinders or the diver though.

The Cornelius would not work for HP cylinders.

They were supposedly designed for airplane hydraulics--I have more information somewhere but I'll have to dig it up. The model I am using (130R1500) was specifically designed for filling scuba tanks. The US Navy had something to do with it. It was manufactured in Minneapolis--what more could you want?

Yes, mine has a filter which I re-pack myself approximately every 20 tankfuls. I am using Nuvair 751 which, after a lot of research, appears to be the best choice for this compressor. I have inspected cylinders after several fills and have not seen any signs of condensation, oil, etc. I let it rest between fills. The water trap appears to work very well.

 

[OkByMe]

That compressor on EBay may not be suitable for the use they claim. I sure would like to see a mechanical drawing on that job. It looks like it is a stacked 2 stage compressor. I'm guessing the piston from the lower cylinder is driving the high pressure ram, which would mean both are stroked together and is unbalanced.There does not appear to be any filter for the air going into the compressor to protect it and the air you will eventually breath from airborne abrasives. I think it is funny that they are using a plastic aquarium pump to feed the water cooling around the cylinders instead of a water hose at house pressure with a flow control valve. I can't see where the other hose is going in the picture, but it cannot be part of the compression cycle since it is barbed and the plastic hose would not hold up to any pressure greater than 80PSI. It is probably the after-cooling water dump. It looks like there MAY be a condensate trap after the HP stage where the whip is attached, if it does not have a condensate trap you are going to get water in your tanks. At the end of the whip there appears to be a filter and I suppose the contents of the bag supplied is the filter material. "

50 or 100# reciprocating air compressor oil ( or 5W-40 oil )" How do they keep the lubricant form contaminating the gas? You should not be using that in a breathing air compressor. The stated air flow rate of 72L/min is a little disingenuous... that may be the 1BAR volume, but does not translate into the output rate since that is dependent on compressor efficiency. The stated 15 minutes to fill 1L to 300BAR. Most SCUBA cylinders are somewhere around 12-15L...Calculate the time to fill you tank. The current draw can be up to 8AMP. at the high end of the fill. (1800W/220V. - Volts X Amperage = Power) My compressor draws (220V) 7.2AMP at the end of a 4500PSI. fill, and the output rate is about 3CFM. This looks like another Chinese contraption to address a possible market demand. Looking at the pictures... The machining of the ram cylinder is a little rough - that and the ram should have a highly polished finish. The cooling jacket fins in one picture show them to be concentric, however in the the assembly line picture, they are all bent up, so does that speak to quality control? I made a previous post in this thread showing what a "real" compressor looks like and some of the costs. The entry level costs are going to be much higher than this one.

 

[Schwob]

That compressor on EBay may not be suitable for the use they claim. I sure would like to see a mechanical drawing on that job. It looks like it is a stacked 2 stage compressor. I'm guessing the piston from the lower cylinder is driving the high pressure ram, which would mean both are stroked together and is unbalanced.There does not appear to be any filter for the air going into the compressor to protect it and the air you will eventually breath from airborne abrasives. I think it is funny that they are using a plastic aquarium pump to feed the water cooling around the cylinders instead of a water hose at house pressure with a flow control valve. I can't see where the other hose is going in the picture, but it cannot be part of the compression cycle since it is barbed and the plastic hose would not hold up to any pressure greater than 80PSI. It is probably the after-cooling water dump. It looks like there MAY be a condensate trap after the HP stage where the whip is attached, if it does not have a condensate trap you are going to get water in your tanks. At the end of the whip there appears to be a filter and I suppose the contents of the bag supplied is the filter material. "

50 or 100# reciprocating air compressor oil ( or 5W-40 oil )" How do they keep the lubricant form contaminating the gas? You should not be using that in a breathing air compressor. The stated air flow rate of 72L/min is a little disingenuous... that may be the 1BAR volume, but does not translate into the output rate since that is dependent on compressor efficiency. The stated 15 minutes to fill 1L to 300BAR. Most SCUBA cylinders are somewhere around 12-15L...Calculate the time to fill you tank. The current draw can be up to 8AMP. at the high end of the fill. (1800W/220V. - Volts X Amperage = Power) My compressor draws (220V) 7.2AMP at the end of a 4500PSI. fill, and the output rate is about 3CFM. This looks like another Chinese contraption to address a possible market demand. Looking at the pictures... The machining of the ram cylinder is a little rough - that and the ram should have a highly polished finish. The cooling jacket fins in one picture show them to be concentric, however in the the assembly line picture, they are all bent up, so does that speak to quality control? I made a previous post in this thread showing what a "real" compressor looks like and some of the costs. The entry level costs are going to be much higher than this one.

Here go the last chances for Pete to decide to be a guinea pig for this thing...

 

[JamesBon92007]

That compressor on EBay may not be suitable for the use they claim. .

Somehow I missed the link the "that cmpressor on eBay." Where is this compressor? It sounds intriguing, if only to teach us what not to buy

 

[Schwob]

Somehow I missed the link the "that cmpressor on eBay." Where is this compressor? It sounds intriguing, if only to teach us what not to buy

Post #29

 

[The Chairman]

Yeah, I posted this with tongue firmly planted in cheek. I have not ordered it and don't feel like be the designated guinea pig.

 

[JamesBon92007]

Post #29

Thanks. For some reason I expected it to have been posted by OP. I get it now

Wow, how economical--you can use plain ol' motor oil

 

[The Chairman]

One of the tenets of buying gear: if it looks like a toy, then it's probably a toy.