Compressor alternative for a Siphon Burner

[Harry]

The tiny compressor got its first real run today with about 5 hrs of casting. It worked great but I did fine a few things different from my bench test. The big one was due certainly to the 20' or so of wire from the control to the pump. When I had tested it I just had a short lead and now on this long run I only got 8 PSI and that was at startup. Within an hour it had dropped to 6 PSI and the temperature on the pump was holding just below 150*. Not sure if it was the temp that made it drop or if the power supply wasnt putting out like it should after it was running for awhile.

So, it works but could be better. I am going to keep my eyes open for a PS with some more oomph or move it closer to the pump, I dont really need to adjust this once running so it could be near the furnace. Will also be getting another pump to run together with this one since I will need two for the big scrapper anyhow.

The goal here will be to end up with at least 10 PSI from a single pump and pushing 20 running two of them.

Sure was nice not to have the big compressor come on a single time during that 5 hrs, the initial load of air was enough to run the jolt squeeze and the blower I use cleaning molds before closing them.

[Jammer]

5 hours of casting,... I'm either working or sleeping.

Sounds like the little pump is doing good. I'm going to check the one I have that is similar, maybe I'll take the old oil burner off the shelf. My garage compressor is trying to crap, well it's from Harbor Freight and is well past the 90 day warr.

[Harry]

Mine is a HF too Jammer and well past its warranty. I never buy those extended warranties though I probably should have on this one. It was only $99 for a 3 hp compressor though and it makes air pretty good I just didnt like it cycling so much from the the furnace and this Tiny Compressor certainly kept it from doing that.

I did have the regulator blow apart on it so I just removed it. The compressor is hooked up to a 250 gallon tank and everything off the tank has regulators. The regulator that came with the compressor came apart once over the winter from getting some water in it and freezing I think. It blew out the o ring, I took it apart and reseated the o ring and put it back together and had no problems for several months then one day I went out to the shop to find the whole top of the regulator gone... still havent found some of the pieces

If you have a pump you are half way there. Just need to find something to turn it fast enough to make air.

I still would not mind finding a better low psi pump, something that would make a little more air at a little higher pressure. Just guessing I did not find the best pump right out the gate for this.

[Jammer]

Mine was set up on a light table as a vacuum, it has a 120 v motor on it. It pulls 20 in/Hg so it sounds a lot like the one you have. Small gast pump. I'll check it for pressure. I was going to try to use it for a vacuum mold table to use a shrink wrap and vacuum it down to the part and then pack sand on top of it. Like the V-cast method, I may have to use the big Vac-pump for that. That project, like all my other ones are on hold.
Do you have it hooked to a tank? I wonder if you put some pressure in a small tank with the big compressor if the little one could just keep it steady around 10 psi?

[Harry]

No tank, just a free flow through the burner. Dont think I want to introduce the compressed air back into it. It did hold 6 PSI fine and moving the current power supply closer or getting something with a little higher amperage it should have no trouble holding 10 PSI. Just need to get some RPM on the motor.

Thats a nice looking little pump, the design is quite different. I wonder if that isnt a little scroll pump? The top end pressure for this application is half the equation, the other half is volume. These nozzles need about a 1 CFM and of course the higher the pressure the greater the volume.

[Harry]

I moved the power supply over close to the pump and it started out with 11 psi which slowly started to drop as the pump warmed up. Was still holding 10 psi when suddenly the pump stopped. Checked the fuse in the PS and it was good so I put it back in and it started up. Ran for another five minutes or so then stopped again, after a few minutes it would come back on but then just quit. Seems like an internal reset is heating up and kicking it off then resetting once it cools a bit. The motor says 1.5A at no load and the PS is supposed to be 2A so I am a bit confused. There is very little load on the motor and I ran it connected with short leads to the pump for a half hour or more when I first got it for testing. Maybe it is warmer today than it was when I tested it before but it ran fine yesterday which was just as warm as today when I had it on the long (20') leads, shouldnt it draw more power on a longer wire?

I am thinking I am going to have get something a little bigger for the power supply, going to try out my little battery charger. I think it is 2/5/10 amps and puts out about 14 volts. Hope I dont smoke anything.

[Harry]

I found the pump I want but I am not even going to bother to ask them how much Just have to wait for someone to buy a 1000 of them only to find they do not suit their application and they end up on Surplus Center for 50 bucks

Looking at another power supply on eBay, this one is 5 amps and 15 volts which is two and half times the rated amps of the one I have. I sent the seller a question on it to see if they think it would be ok for the current setup.

[Harry]

Looks like I may have a solution to the power supply problem. I took the top off and put a little 12v computer fan on it and it has not gone above 130*. Before I put the fan on I tried it again with the top off and measure the temp on one of the heat sinks on the board. It shot right up to 200*, running now and has been for the last two hours. Plus I found a little adjustment pot inside and turned it up a little. I am getting about 8 PSI after it has warmed up so this is looking much better than it did yesterday.

[dallen]

great Harry, I been thinking about trying oil be nice to not have to hunt for a year for stuff like I did with my roaster. yea most electronics don't like it hotter than 120 they trip out

[Harry]

I have been putting the eyeball hard to this little compressor on eBay. He says he has 20+ of them so I sent him a note to find out what he would let a few go for. According to the spec sheets I found here and here it is .88 CFM but the most interesting thing was on one of the sheets it claims a 6000 hr lifetime.

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This one is a piston vacuum/compressor but I have also been looking into pond aerators. Sure looks like this one might be well worth the price and at 60 db it is probably no louder than the flame in the furnace.