How to weigh a train car?

rankhornjp · May 21, 2015

I have a customer that is wanting to measure the amount of product (kinda like flour) they are loading into train cars. They are trying to maximize the product in the train car without going over weight.

They are gravity feeding the train cars from a hopper. (can't weigh the hopper cause it is being filled at the same time it is being emptied)

Rail company won't let them put scales on the tracks.

Any suggestions on how to do this?

osmanmom · May 21, 2015

how about install portable weighing with shutter

Sergei Troizky · May 21, 2015

1. How do they know they are not overloading presently?
2. How will they prove to the rail company they are not overloading, after whatever solution is implemented, if it is not direct weighing?
3. What min/max weight? What precision and what resolution is required for weighing?

dginbuffalo · May 21, 2015

Not the best, but you could probably put a rotary feeder under the hopper and figure out how much product is dumped per RPM. Problems are keeping the feeder flooded without jamming, bridging and density variations.

Lancie1 · May 21, 2015

For fertilizer plants with rail loadout docks, we installed a weighbelt feeder that fed the loadout hopper, then weighed the fertilizer going into the hopper.

califflash · May 21, 2015

You could implement a dual weigh hopper system. Use a diverter gate to switch hoppers. Fill one hopper until you hit a set point then switch. One hopper dumps while the other is filling.

I imagine you could also use a conveyor belt with a check weigh system to determine lbs of product per foot of travel. That would probably be much faster.

rankhornjp · May 21, 2015

osmanmom said:
how about install portable weighing with shutter

Please expand on this thought....

Sergei Troizky said:
1. How do they know they are not overloading presently?
2. How will they prove to the rail company they are not overloading, after whatever solution is implemented, if it is not direct weighing?
3. What min/max weight? What precision and what resolution is required for weighing?

1) they get fined when they are overweight. They pay the freight even if the car is "light" This is what sparked this discussion.
2)My understanding is that the rail company has a way to weigh the cars, just not at this site. Hence, the fines for being over.
3) not sure, but most rail cars around here go 50-80 tons.

dginbuffalo said:
Not the best, but you could probably put a rotary feeder under the hopper and figure out how much product is dumped per RPM. Problems are keeping the feeder flooded without jamming, bridging and density variations.

Interesting idea, but I think the possible issues with it put it down the list of possible solutions.

Lancie1 said:
For fertilizer plants with rail loadout docks, we installed a weighbelt feeder that fed the loadout hopper, then weighed the fertilizer going into the hopper.

I'm being told there is not enough room to install a conveyor. (my first suggestion)

califflash said:
You could implement a dual weigh hopper system. Use a diverter gate to switch hoppers. Fill one hopper until you hit a set point then switch. One hopper dumps while the other is filling.

I doubt they have the room, considering they don't have the room for a conveyor, but I'll ask.

Thanks for the suggestions! If you have any more, let's hear 'em.

JesperMP · May 21, 2015

Cannot weigh the whole car.
No room for belt-weigher.
No room for weigh-hopper.
Not so easy.

What about an optical laser scanning of the entire car, when empty and when full, and then calculate the weight of the volume of material ?
Something like this:
https://www.sick.com/de/en/fluid-sensors/flow-sensors/bulkscan-lms511/c/g253553

Flopro · May 21, 2015

Impact Plate

I use these type of flow meters for dry solids when I have similar situations. Several companies make similar designs.

http://www.rospen.com/products/continuousweighers/impact-plate-flowmeter

http://www.accuratefeeders.com/massflowmeters.html

Lancie1 · May 21, 2015

I'm being told there is not enough room to install a conveyor. (my first suggestion)

It only requires about 6 feet out of the existing conveyor. In other words, you have to make the exisiting belt feeder 6 feet shorter to make room for the weighbelt section. What I hear is "there might be room but we are not willing to do what is needed to make it work". With that attitude, nothing will work.

George Graziano · May 21, 2015

We find not all cars have the same capacity. Do you want to fill to a known weight?

TConnolly · May 21, 2015

Who owns the tracks under the hopper?

skeet · May 21, 2015

+1 to Lancie1....
We use this to weigh salt on a short conveyor. Works great.
http://www.accuratefeeders.com/bempdata.pdf

rankhornjp · May 21, 2015

Flopro said:
I use these type of flow meters for dry solids when I have similar situations. Several companies make similar designs.

http://www.rospen.com/products/continuousweighers/impact-plate-flowmeter

http://www.accuratefeeders.com/massflowmeters.html

I really like this! I will look more into it. Thanks

Lancie1 said:
It only requires about 6 feet out of the existing conveyor. In other words, you have to make the exisiting belt feeder 6 feet shorter to make room for the weighbelt section. What I hear is "there might be room but we are not willing to do what is needed to make it work". With that attitude, nothing will work.

There is no conveyor on the "OUT" side of the hopper, it is gravity feed directly into the top of the rail car. So, you would be weighing the product going into the hopper and "product going in the hopper" != "product going in the rail car"

George Graziano said:
We find not all cars have the same capacity. Do you want to fill to a known weight?

They want to fill as close to max weight as they can get without going over and getting fined.

TConnolly said:
Who owns the tracks under the hopper?

The rail company.

ndzied1 · May 21, 2015

I guess if you get this going, you will be justified in putting up a sign I saw a long time ago:

We the Willing
Led by the Unknowing
Are doing the Impossible
For the Ungrateful

We have done so Much
For so Long
With so Little
We are now Qualified
To do Anything
With Nothing

How to weigh a train car?

rankhornjp

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