Dry Bulk Trucking Operators

From my limited experience hauling dry cement, loading or unloading can vary from about 40 minutes to well over an hour. It depends on how well the product flows. Some dry cement mixes are quite "sticky" getting through the hoses.

I would imagine that pellets would flow very well, but I have no experience with that kind of product. Others with far more experience can give you a better idea.

 

Bulk Cement 45 to 1:10

Here is the thing, They like to fill to 14-15PSI in the main tank. (The whole trailer) I am always conservative at 12. The last three PSI is reserved myself for room to do things that I might need to do with it.

Mortar, I hauled one load in a Butler to American in Overlea off US 40 and that was a fiasco. Took 4 hours for whatever reason.

I always love to use the building's air. Not my exhaust air. I can lean on the bulding's 400 HP electric motor much easier than that pitiful turbo behind my cab. One facility, Lehigh export across from Fort McHenry in Baltimore Md at the waterfront, they have a facility wide system of air. Once you are empty in 40 minutes with your tanker singing. (Literally singing) you need to cut everything off because now you are starving the other 20+ trucks. You do NOT want blame for plugging up 20 people.

Training in bulk is straight forward, I have no problem unloading one today, it's literally riding a bike. (Like I really should not at my age...) it's not that difficult.

The other things are two, first you need to be off pressure in that trailer before going up top. Second is that you make sure you have no people on the other side of that blow down pipe. You might cut them in half with the ones we had.

If that does not focus your concentration...

 

Unload time depends heavily on the product and where it's going.

Ex: I'm working with pebbled limestone right now, 1/2"-3/4" diameter, pushing about 70 feet, 55 straight up, with a powerful dust collection system, can unload 24.5 short ton in around an hour.

Ex 2: Another limestone product, more like a coarse sand, pushing about 75 feet, 50 straight up, decent dust collector, 27.5 short ton in about 2.5 hours.

Same truck, same trailer, same source for the limestone, same unload pressures, but two different sizes and densities.

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What specifically are you looking for?

 

I deal with plastic pellets of various types from time to time. Several variables can determine length of time when unloading. For example, just last week I delivered two loads to a 3M plant in South Carolina. Each trailer (just over 46K lbs of product) took about 4 hours to unload.
Those unloads took so long due to type of pellets somewhat, but primarily due to the distance the product had to be pushed. Unload it at over 8 lbs psi and it's likely to plug up. Conisering the trailers had no vacc unit, getting plugged up is NOT a good thing.

That said, we also carry a different type of pellet to the same plant, and unload them in a couple of different areas of the plant. In the area I unloaded last week, I can unload this type pellet about 2 to 2.5 hours. Again, due to distance I'm having to push the product. In another area, I can unload the same type pellet in about 1.5 hours. At this area the pellets are basically going out of the trailer into the line going up the side of the hose, unloaded at 10-12 lbs psi.

Other times I'm unloading into a railcar. Takes only about an hour to unload. Even then I'm not going above 12 lbs psi, because as has been stated by another driver the product can get overheated and damaged, and also because of the risk of getting plugged up. And even with a trailer that has a vacc system on it, the amount of time one might gain by unloading at higher lbs psi will be lost if you get plugged up and then have to switch from unloading to vacc, get unplugged, then switch back. (Yeah, I know...that sounds about as clear as mud, right? lol)

Anyway, with the right training it's not difficult to learn...at least the unloading isn't. Vacc loading is a bit trickier, learning how to balance the load evenly.

 

My absolute knowlege on plastic pellets arrive by railcar pressuraized ACF Hoppers. They load em up with air, unload one pot at a time as the pellets are used by the factory in making all kinds of plastic etc. Unloading those is the same as unloading any bulk tanker just not so hard.

There are some chemicals delivered in pellet form but as for that kind of information, you will discover that it is a aura of secretiveness about that kind of work. I literally know nothing about chemical pellet desipite my own extensive research into industry pre steam era and post modern in railroading. It is a relatively new method.

I have been around chemical railcars being unloaded twice with also Hazmat on them. Maybe pellets maybe something else. You do not get to stand in a laydown unloading area around rail cars or trailer trucks unload that material any length of time. You get run off before you can think of nice questions to ask.

At the end of the day, if it's in a air filled bulk tanker or rail car. you pump it up, then BLOW it off. Out it goes into a internal factory bin or up top into a silo above just like anything else.

 

Plastic is a generic name for a variety of resins. Some [think ABS] look more like little slices than pellets. They can come in a variety of densities and there are additional oddities like lubricated pellets that fly out of the trailer.

Stack Turbo's are too hot for plastics.

high density resin is harder and less likely to form X-mas tree decorations in the valves...

One of the most dangerous liquid chemical products I've seen transported was transformed into pellets for use as a catalyst for another companies chemical production [ we hauled the waste by-products to be burned...finished product looked just like a low density polyethylene pellet, go figure...

I delivered caustic soda [calcium hydroxide] pellets that melted into a corrosive slime if in contact with humid air where your blower sucked in air from a large Desiccant tank mounted on the back of the wagon to insure DRY air and you blew it thru the customer's plumbing for 30 min. before cracking a valve because you just can't plug up.....

So the unloading time is dependent on the actual product.

The lubed plastic I mentioned above could vac on in 25 minutes and off load almost as fast using an experienced operator who could vac and off load a full rail car in one day...the stuff was so EZ he would open #2 and off load 90% of the load before going back to #1 which only took 5 min. or so before walking back to #3 and #4...most low density plastic would have melted in #1's valve from the heated blower air, DO NOT TRY THIS!

Higher density plastics go faster and are less likely to form angel hair or streamers and melted X-mas tree ornaments in the valves, however they will cause more abrasive damage to fittings and such.

Hoses can be one-way -or- bi-directional, blow soft resin the wrong way and then a higher density product in the correct direction and you just contaminated the silo...Vac on without keeping the hose off the ground can suck in dirt too...Pharmaceutical resin with one spec of dirt gets downgraded to a technical level product loosing around 80% of it's value which your insurance will not be happy paying.

You need to know what you are dealing with...

 

Most resins come in hopper cars. PD rail cars are usually powders like pigments, flour but Pellets unload thru a rotary pipe that rotates an opening under either the 'near' or far' side of the hopper letting the pellets fall into the tube to be drawn away by vacuum [ten points to anyone left who has bear-trapped] either by a transfer [suck/blow] machine or a vacuum [self-loading] trailer