Pneumatic 101

You don't get a choice on how much per hopper, because you load one hole and it flows like water. If you have a 1000 cube trailer load the last hole or it will be too heavy on the front. You can bounce it once or twice if necessary but then it will be settled and won't move. When unloading you can run it at 14psi, just make sure you have the line air valve open before the product valve so it doesn't plug up. line air should be about half open, but you can adjust it if the pressure goes up or down. The trick is to blow cement, not air. I used to unload 52,000 in about 45 minutes

 

the entire trailer will hold more than you can haul legally. I happen to know a 1050 cubic foot tanker will hold 120000 of type 1 cement. I got to see it done one morning while in line to load. All I know is something broke at the silo and couldn't be shut off.

What does each hopper hold? I haven't a clue. I figure since it flows through and levels out when loading, it should be roughly the same in each hopper.

Pressure? Can depend on the customer and their wishes. One place I go wants no more than 10 psi. Most don't care. That being said, you should never go over 15 psi. That's the recommended highest pressure, but I have gone over many times with no problems.

Pressure is relative anyway. The idea is to blow the most product with the least pressure. ..I normally unload 26.5 tons in 35-45 minutes, at 13 psi .

But all trailers are different. What works with one won't work with the next.

Your last question I'm not sure what you're asking, but I'll try. Your line pressure should be roughly equal to the tank pressure when unloading. A pound higher or lower won't hurt.

 

Btw, don't use top air to pressure the tank, just the aerators

 

I'll second that!

 

One other thing I'd like to add to this: you do not need to run your blower at full speed to unload. I've found it to work better at lower speeds. For example, with my truck the blower is at full speed at 950 engine rpms. I usually unload at 850 engine rpms. Running the blower faster usually just increases tank pressure and then you have to babysit the trailer. With slag I unload at 750, in about 30 minutes

 

In my cases it doesn't matter what's higher or lower when it comes to tank or line pressure. As long as the hose jumps and you know what your doing you'll be fine. I've had my tank at 22 psi and line at 26psi. It's not the safest by any means but that's how I found out the trailer blow offs where bad

 

I alwayse unloaded my old bulker at 12.5psi... corked was about 44t ... no idea what that is in lbs