Pneumatic Tankers ?

I am a dispatcher/batchman at a concrete plant, and don't know much about them, but I can tell you what little I know.
First off, I have no clue about the differences, but I know some have blowers and some don't. We actually had to purchase a blower that we can hook to a truck if needed.
I get loads of fly ash and cement.
The one's we use have three hoppers. The driver goes to the cement/and or flyash company and loads or has the tanker loaded from the hatches. He/she climbs on to the top of the trailer to open/close the hatches. I had to get a sample of cement via opening a hatch and scooping a gallon of cement out last week, and I will tell you first hand, it's no fun.
Ok, something I learned from the new driver yesterday. DON'T TURN ON THE BLOWER FULL BLAST TO BEGIN WITH. Gradually open it up. You will be emptying each indivual hopper.
The driver uses a mallet to hit the heck out of the hoppers, and get the residue of the fly ash or cement off the inside sides.
if the hose ain't moving it might be clogged, such as what happened yesterday with the new driver.
That my friend is no fun. That's why you must GRADUALLY open it up.
Again, when loading a silo, the hose should be wiggling around like a scared snake.
You said cement plant, but incase you handle fly ash, I am going to ad this just in case. MAKE SURE YOU GET THE LOI for the fly ash. If not you're going to have a grumbling plant manager, and an unhappy dispatcher/batchman somewhere out there silently cursing you.
Hope I helped a bit.
Oh a side note, I hear that flour is worse at clogging than cement.
Oh, and something else in case you ever deal with fly ash.... FLY ASH GOES WHERE WATER WON'T!!!!!!!!!!!!!!!!

 

http://en.wikipedia.org/wiki/Loss_on_ignition
It makes a HUGE difference on the concrete. If the batchman knows the LOI he can compensate to an extent on the bad fly ash load he was delivered with chemicals, and make the concrete the way it should have been with good fly ash. All fly ash loads have an LOI number on the bill of lading...... or atleast they're suppose to. I get alot without them.
Mineral resources sells good and bad ash, while Sefa usually has nothing but the best.

 

Oh, and I must ad, my company orders mineral resources 9/10 so the LOI is extremely important for me.
There are two places the drivers get it from, I think it's silo A and B, not sure. I also think Mineral resources in is Louisville but again I am also not sure. Anyway, one of the silo's usually has really great ash, while the other usually has the crap load.

 

i prefer cones over pads as they aren't as prone to clog up over time.
old pads make a great tank suck.

i believe that dry bulk tanks are much more stable than most others!!
i"ve done some pretty stupid things in 10 years of them and NEVER
wished i had any other trailer in those situations.

 

Generally, 40 tons of cement takes about an hour and a quarter to hour and a half at 15 psi.

 

you must have a stack blower!!!!!
20 mins. into a pig
30-40 into a silo
at worst places 50-75 mins.

25-26 tons cement, fly ash, lime.

Drum pto blower.---- 15 PSI