I had a weird problem with an air off today.

I was delivering latex to a customer that I've been to a hundred times. They supply the air. So I hook up their line to the inlet on the dome and hook my hose up and all that and wait for the lab to give the okay.

Well, as soon as they do the customer turns the air on and immediately I hear a leak. Bad air leak around the dome. No big deal, old trailer its happened to all of us. I beat the dogears with a hammer and the leak stops. Product is flowing nice, all is good.

I have a suspension gauge that allows me to tell about when I'll be done. Well the gauge just stopped going down after 45 minutes. I was almost done and it just wouldn't move. I figured my internal had fallen or something. I checked everything and all was working fine but I wasn't moving product. Finally, I go up top and check the air. Like I said, old trailer no guage, so I did it the old fashioned way. Shut off the customer air, disconnect and open my inlet valve. The air is barely coming out and all of you tanker guys know what I mean. When the tank is pressurized, opening that inlet means noise and a whole lot of air coming out you can't mistake it.

I checked the customer's air and it was pouring out just fine. I hooked it back up and tried to pressurize my tank and it just seemed to be getting no air. Finally, I cranked up their regulator to 45 psi and after 5 minutes, started moving product.

So here is the question, why did my tank get air and then suddenly stop? I know some will say blockage but how can an inlet get blocked while there is 25 psi pouring in? I had good pressure, I was moving product fine and then it's like the air just vanished. The customer air was on the whole time, no valves got closed. I know the air went into the tank fine because remember I had the leak and that was no small trickle of air. Basically, it seemed like a blockage, but one that occurred during an offload. I can't figure this out. The inlet was one of those long tubes that goes straight into the dome, very old fashioned. I put a screwdriver in there and felt no blockage. In any event, it stumped me, I have done hundreds of off loads and never ran into this. There was no other leak, heck you can hear a high pressure air leak easily. The washout caps and dome were silent. Any ideas?

 

One hose, top loading tank and I've delivered there many, many times. Eventually, after I cranked it up to 45 psi it started to flow again. I just can't figure out why, when you have a steady supply of air, the tank would run low.

 

It was hot, I don't think that happened because I never caught it doing that but it is a possibility.

 

That is a good idea, nice thinking. I'll ask about that next time I go there.