Compressor project

[toddah]

So you know how projects go one thing leads to another and soon you are knee deep in a new project you never intended to have to do.
My wife and I have been fabricating a fencing system for our backyard all summer and the weather called for nice days for two days over the weekend so we setup and started spraying the fence sections that had been fabricated from 3/4" and 5/8" re-rod over the summer. I had all of the sections done except 3 and I said to her over lunch break that we would be don in about an hour so we would have time for a motorcycle ride. 10 minutes after lunch my trusty old frankencompressor that has been pumping air for 17 years seized a rod to the crank. I had to run out to HD and picked up a Husky 60 Gallon 3.2 HP tank unit and quickly re-plumbed it into the air header system in the shop. nice and quiet but it would not keep up with my HVLP gun like my old unit did so I decided after the fence was up and painted to rebuild the old V twin compressor head. But to my dismay I could not find any identifying tags or stampings on the cast iron except C6 on the block and rods have A3 on them. BUMMER.
I went to craigslist and lo and behold I found this Rol-Air K30

Picked it up the next morning for $200.00. The kid that had it said it was his uncles and he got it for free on a gas compressor with a 7.5 HP Honda engine on it. he took the motor off and used it for another project he was working on and " had no need" for the "old pump" without a motor.
Seems to be in great shape and pushes and pulls air when rolling the flywheel. I spent last evening mounting it up on my 80 gallon "old iron" tank and 5HP 220 motor. if all goes well I will be resurrecting frankencompressor for the second time in my ownership.
Question was this s good deal I am not a compressor guy but I know I can never have enough air in my shop. always wanted to be able to run a small blast cabinet but my other pump just could not keep up. Hopefully this one will.
If all else fails I can rebuild as it looks like parts are available. Seems to be built like a tank. Must have had 2 quarts of oil in the block when I drained it and the oil was really clean and the kid said he never changed it.

What do ya think is it a good pump for the money?

When I plumb from the outlet on the compressor to the tank should use 3/4 black pipe or copper tubing. is there a reason not to plumb it solid with hard pipe? My old head was running on 4 wire hydraulic hose with explosion proof fittings for 15 years but it was smaller inside diameter so I am replacing the feed tubing.

I am replacing the pressure switch to one with a blow-off line from the check valve in the tank inlet, is there anything else I should be thinking about or overlooked?

 

[larry_g]

http://www.rolair.net/products/spec_pages/pumps_belt_drive/PMP22K30CH.html#specs

The above link spec's this pump at 800 rpm for 5hp motor. Pay attention to this and after assembly monitor the motor current to make sure that your not over currenting the motor and you should be good to go. I would use copper from the pump to the receiver and make sure that the check valve is in the system.

Good Luck

lg
no neat sig line

 

[GeneralDisorder]

On any reed valve machine of unknown age and usage it's a good idea to replace the reed valves - they are cheap and you have the opportunity - all you have to do is get a set of valves and the gaskets for the plate. If one should break and fall into the cylinder it will hammer the piston and cylinder walls to death. Cheap insurance.

Make sure your tank is setup for a form-x style installation (tank check valve and pressure relief via a form-x pressure switch). Some pump styles have centrifugal unloaders or hydraulic unloaders that eliminate the need for the pressure relief or in the case of hydraulic unloaders such as on the Quincy QR's they have no need of the tank check valve itself.

As Larryg says - monitor your motor amps with a meter when you setup the machine. Set it for 800 RPM operation by changing the motor sheave if necessary, and set the max pressure somewhere below the FLA of the motor. Several amps below it is ideal but if you need the pressure and the motor is a quality one you should be able to run it at FLA x SF if you really need that much pressure.

GD

 

[toddah]

Well I was able to find a double A sheave that should spin the compressor at 779 rpm and while I was at it I ordered a new pressure switch, blow off valve and check valve. I took out the in tank check valve and realized it was a 5/8 valve adapted to the 3/4 hole and it has been in use for at least 17 years I have owned the tank so I decided to just replace it with a 3/4. I had my local tubing and hose shop make me up a 3/4 stainless steel flex pipe with a Teflon liner for the feed tube. so as it stands I will exit the pump in 3/4 black pipe run around the corner of the head and then a 3/4 union then the 15" flex pipe to another 6" black pipe into the tank check valve.
I bought the Pressure switch with 4 ports and an automatic pressure release plus an on off switch.
I spoke with the service manager Josh at Rolair trying to order reed valves and he would gladly sell them to me but he said the compressor was manufactured after 1997 (intake port is threaded) and the valves are never a problem on these compressors. he said the weak spot on these are the upper wrist pins but they would rattle for years before actually giving out and that was only seen on 24 X 7 industrial use for years. He said the noise would drive you to fix it before it actually broke.