Compressor Tank Drain Extension Pipe Inside?

[Reseda]

I bought a fixer compressor with a Kellogg pump, Leeson motor, and a tank that is labeled "SCAIFE". I'm new to compressors and bought the whole thing on a little bit of a blind faith. The seller advertised the pump as a 5HP. I found out later that it was a 2 HP. A "dammit" moment but figured it would still work for what I want to use it for.

I'm in the process of flushing the tank.

It is a vertical tank with a drain fitting at the bottom. The previous owner fitted some pipes and a ball valve at the drain. I have removed one of the inspection plug. When I looked inside, I noticed that there is a pipe going from the bottom drain fitting to a side fitting, which is plugged.

What is this pipe extension going from the bottom drain plug to a side fitting? The pipe is inside the tank. What is it's function? I was under the impression that a typical drain plug is just a fitting with with a valve: no pipes.

Thanks.

 

[CNGsaves]

Welcome to GJ.

Really hard to picture what you're talking about without pics.

Besides, let's SEE the Kellogg compressor !!

 

[600SL]

That pipe inside is for a bucket drain. It just plums the sump of the tank to a higher point out the side so you can put a valve with a bucket under it. You also don't have to bend down quite so far. A nice feature but I don't believe it will drain it as much as the bottom drain.

 

[Todd.Brock]

It sounds similar to a Champion auto drain. These things cornfuzed me until I took one apart. There is an apparatus that uses the unloader pressure to **** the water out of the bottom of the tank using that hose. It's a Venturi effect , I think,? Essentially the compressor would shut off, the diaphragm apparatus would reroute pressure down to the bucket high drain and meet the hose going to bottom of tank. There maybe some details I'm missing, but it's the basic process. There are no electrics, pumps, motors, etc. Involved. Simple in theory but a bit fiddle with all the connections, etc. I was missing half the tubing and removed the setup. I too pulled a hose out of bucket high drain and had an aha moment.

 

[redmondjp]

As stated above, that tube is nothing more than a "force" drain that exits the tank at a higher point. There would have been a valve where the pipe exits the side of the tank. My Snapon BRA7180EV has this exact same setup with a ball valve that is spring-loaded so you can operate it with your foot to quickly drain the tank.

Liquid accumulates in the bottom of the tank. It has tank air pressure on its surface. The lower end of the tube is at the lowest point in the tank where the liquid accumulates. When the valve is opened at the end of the tube, tank pressure forces the liquid down and then up and out of that tube. It's pretty ingenious IMO - some other person besides me hated getting underneath their tank to drain it and came up with this solution.

 

[Reseda]

Thanks for the welcome and the responses!

Makes sense now. Which now makes the bottom drain look like someone's retrofit because I don't see why the tank would be manufactured with two ways of draining. I've taken apart the pipes attached to the bottom drain and there's no bung but only a tapped thread through the wall. Is this tapped hole safe to use or plug?

My heart sank when I took a peek inside and saw about 2 inches thick of rusty stuff that looks and feels like orange-brown soil with flakes mixed in. I'm flushing it out and have most of the stuff out but I'm slowly losing hope that this tank will be good. There's a dat on the tank that reads "1953" I don't know if that's a patent date or manufacture date.

I'm getting it ready for a hydro test. I have the holes plugged and just waiting for the pressure gauge to arrive.

Here are pics...

It's in bits and pieces. I have ordered a pressure switch, etc.

The tank, which I don't think is original with the pump.

Gauge, which I think came with the pump because of the Kellogg blue paint.

Kellogg 321TV

Leeson 3HP 230V single phase motor. Another retrofit.

The mess...

 

[600SL]

Definitely a quality compressor. Its small but a 2 stage 2HP like that is a very high performance 2HP compressor.

 

[Reseda]

Might as well make this my build thread.

Damn, this thing held 300 psi I guess those thick walls last a long time.

I performed the hydrotest and was able to peg the 300 psi gauge. Held it there for about 2 hours. There were a couple of plug leaks that appeared around 120 psi but once the plugs were tightened, the pressure did not drop. I actually stopped pumping about a hair before 300 psi but the needle kept climbing until pegged. I wasn't too confident about the bottom plug holding but it held fine and not a single weep.

I'm sanding the tank now getting it ready for paint. I found a sticker under the paint that read "LYNCH"

Next up is the pump. I've already removed the head and discovered rusty gunk on top of the pistons and valves. I'm waiting on the valve kit. Will need the tools to remove the valve.

 

[rsieracki]

please explain how you hydrotested your tank... i have one i need to do myself

 

[Reseda]

I followed the method used by others in this forum. I plumbed a ******, ball valve, 1/2 to 1/4 bushing, 1/4 to 1/8 bushing, and then an 1/8" grease zerk. I added the ball valve for a positive shut off because I figured the ball bearing check valve inside the grease zerk will not be able to hold the excessive pressure. It actually started weeping with just the weight of the water, without any pressure.

I plugged the rest of the holes not needed and put a 300 psi gauge on one. Filled it with water making sure to try to get rid of any air. I only had a mini grease gun and that's what I used. A bigger grease gun would probably be better. Then I just pumped grease in until it reached 300. Keeping an eye on the plugs, welds, and the bottom to see if there are any leaks.

This is the setup I used. Let me know if you need a grease zerk. The guy at the store would not sell me just one so I ended up buying extra.

 

[rsieracki]

Just curious how much grease did you have to pump in?

...i've never seen it done like this and i'm curious as i would'nt think that would work if you had'nt told and shown us that it did

 

[Reseda]

Just curious how much grease did you have to pump in?

...i've never seen it done like this and i'm curious as i would'nt think that would work if you had'nt told and shown us that it did

I would like to know what I did that was different from how you've seen it done.

I used about 9-12 ounces of grease. Kind of a hassle when using a mini grease gun. I also had some clean up to do afterwards.

 

[Todd.Brock]

Thanks for the visual as well. I have read about using a grease gun, but somewhat baffled as to why? Is that the only way to pressure the airspace left in the tank? What is the point of the grease? How long is a std test last that it will consider passed at s certain Psi? Thanks for the info!

 

[CNGsaves]

OP, excellent job of pressure testing (hydro) the tank to make sure it's still safe.

Grease gun uses zerk as one-way "valve" to force more "liquid" into the tank. Since contents of tank are water/grease (small amount), there is no significant compression (stored energy) so IF tank leaks/breaks it will just be a water leak (no explosive power).

Welding shops do the exact same thing with bottles (steel pressure vessels) for recertification that are good for another 5 years.

CNG industry does similar hydro test for steel storage bottles, but 150% overpressure test for 3,600 psi vessel works out to over 5,000 psi !!

 

[404]

Fantastic pictures and explanation. Well done indeed!!

 

[Hop2it]

I would like to know what I did that was different from how you've seen it done.

I used about 9-12 ounces of grease. Kind of a hassle when using a mini grease gun. I also had some clean up to do afterwards.

I see a problem brewing for future spray paint jobs infancy grease gets into tank.
Doug

 

[Hop2it]

I see a problem brewing for future spray paint jobs infancy grease gets into tank.
Doug

Don't you love spell check? Infancy was supposed to be if any
Doug

 

[CNGsaves]

I see a problem brewing for future spray paint jobs if any grease gets into tank.
Doug

You don't get it. Grease WILL get in tank. OP will need to wash out tank with water, then degreaser/Purple Power, etc until the tank is fully flushed. He'll dry it out and use another compressor to use compressed air to help push out **** as well. Once tank is all cleaned out and dry, then he'll put it back in use.

It's small price to pay cleaning out tank, as the hydro test was CRITICAL for OP to know whether tank was still SAFE !!

Any one spray painting anyway needs filters and desiccant dryer to ensure that air is clean and dry.

Nice job OP. Good luck finishing up restoration.

 

[killahog]

Thank you for taking the time to explain the procedure . So how long has it been since you rode that skateboard.?

 

[Advan]

Instead of a short little ******, just use a 3' piece of pipe that will hold all the grease before it reaches the tank. Perhaps even an elbow so this pipe is vertical and the grease will float on the water. (Does grease float....?) Lol

 

[jvitez]

Thanks Reseda and CNGSaves for the excellent explanation and pics. I learn something every day from GJ.

 

[Todd.Brock]

Yeah, thanks for tr explanation. I would expect the grease to not dissolve in the water , so it should just be turds floatin...?

 

[Greeny]

Thank you for taking the time to explain the procedure . So how long has it been since you rode that skateboard.?

Had to make multiple passes through the pics to find the skateboard. Some of you guys don't miss a thing!

Thanks OP for the write-up and pics. This is a relatively easy way to gain confidence in what may be great priced find. I'm going to start trawling CL for older, bigger compressors. Rusted out tanks are the biggest concern I had.

 

[Murphy4570]

That is a very handy way to test compressor tanks. I'm gonna do that on a suspect pressure vessel I have before I put it into service. Thanks for sharing.