Maybe search for "rapid rail loading" ■

First off you did not mention the class of truck-road or off road-35 -300 ton etc.

A flood loader for an off road truck would not be a problem but they load to overload them at the pit face in the basin coal fields

so no point in going there unless I miss read your comments.

Flood loading of on road trucks is a no no as it will overload them and break springs and blow out air bags.

The only place I know where this works is the salt beds in austrailia where they are set up for flood loading trailers used elephant walk style with overhanging edges to recieve salt while crawling with the salt harvester in the salt ponds.

These trailers are not ment for road use!!!!!!

At one deep salt mine in particular the trucks are loaded on the scales(the most sensible way to do things.)

The truck is weighed empty to determine its tare weight.

The truck is stopped for filling.

The scalehouse has either A CB radio and or buzzer to direct the truck driver to stop under the chutes.

After filling the the truck the driver enters the scalehouse and the attendant receives payment for the load he or she gives the driver the scale ticket to verify the bill of lading etc. or the paper work for an account recievable transaction.

The truck loading is remote controlled by the scale house operator and the loading chutes and dust control spouts and total gross weight(allowed by the local traffic laws) are controlled by the scalehouse attendant.

Sorry about bursting your bubble but flood loading of coal is usually done with unit trains of 100-135 gondola cars per train and the cars have anywhere from 115 to 135 tons per car capacity each not including the weight of the car bodies and trucks which will hit 50 tons plus with aluminum car bodies and steel bodies weigh even more so.

Whats really scary is seeing those coal samplers climbing around the coal car tops spreading the coal that does not get loaded evenly when the clamshell gates do not shut tight- I wonder how many have been buried? ■

Warning on lorry loading from hopper with clamshell gate.

MAKE SURE THE MATERIAL CAN BE CONTROLLED BY APERTURE!

Visited a site with a lorry loading facility as above, the material being filter cake. I noted it wasn't being used. Apparently during the early life of the plant a lorry came in to be loaded. The clamshell was opened a bit, no flow. Then opened more and more. Suddenly the contents of the hopper flowed into the lorry, over the lorry, around the lorry.

Result, smashed lorry bed, suspension and axle!!

Lorry driver none too happy either.

Take care. ■

flood loading means flood loading AKA an instant snow storm 5 feet deep a la "Bugs Bunny" cartoons-loading to the lips of the clamshell gate is instantaneos due to the above gate bin storage volume-provided it it is not frozen.

If the trucks are road trucks for get about flood loading as it will guarantee blown tires and broken springs.

If you expect to gain any speed with a system you need to consider using a 48-60 inch tripper belt fed by a nearby apron feeder and bin.

The problem is in set up as a hydraulic drive for the conveyor belt is a must have due to the slow speeds needed(for control) and volume(of coal) required.

A small (60 foot) tripper belt assembly(center fed) from the apron feeder(12-16) inch will work nicely but it must be left indoors under cover to avoid problems-No you should not even consider a tripper belt under a bunker or silo!!!!!!!!!!!!!!!!!!!

Any apron feeder of that size will deliver 450 tons per hour plus for your needs and it does not have to be 12 feet long either.

The feed to the apron feeder needs to be gated as well for piece of mind and reduced maintenance problems. ■

Sorry that's too sweeping a statement to go unchallenged!

I know of hundreds of hoppers that load lorries through gates. It's just that as I said in my previous post your material needs to be capable of being controlled by aperture so that the rate can be controlled to avoid excessive loads on the lorry. ■

OK, OK I forgot to say flood loading a truck while moving is a very dumb Idea for the above reasons AKA spillage etc. ■

Ok so you have narrowed it down a bit for your use,several clamshell gates can be set up in series for loading in sequencial order pere length of the truck body but as is the norm every thing has its opportunity cost-what are you willing or able to spend for the system?

What we have done in the past is stopped the trailer directly under the single chute and used a loud buzzer to tell the driver to stop and go while loading the dump trailer which is an inexpesive possibility; but the loading point for the system operator has to be above the truck to see the loading in progress where a tripper can be set up for the length of a trailer of any size as the operator rides along the belt on the tripper itself while loading the coal truck-the methane in the coal seam is properly loading the trailer per weight limits required by the local highway motor vehicle laws; but as the operator is on a catwalk or in above ground scalehouse with a huge window to watch as the trailer can be loaded evenly with either set up manned tripper or unmanned as long as adequate sighting of loading by the operator is available. ■

These days remote control TV cameras

Maybe put the hopper on load cells, load with one lorry load of material, bring lorry underneath loading point, start loading, lorry driver can monitor loading via TV screen (using cameras as above) and move lorry as required.

Use gate or feeder at hopper outlet according to the material flow characteristics. ■

The only bad trouble with load cell mounted hoppers is shock loading and damage from same, breaking at at wrong time every time- that is what makes the loading on a scale rated for heavy trucks that much more sensible.

your turn. ■

Um, so with a fixed loading point you need a long scale say, the length of the tractor unit plus twice the trailer (on an artic) to allow the for traversing under the feed point. Otherwise you need a conveyor under the hopper to traverse along the trailer.

Or you stick with my idea but remove the load cells under the hopper and weigh the infeed to the hopper to get the correct load in the hopper.

Next ■

Yes a differential conveyor is good but-reducing problems to a more managable level is an even better option;

either way you are SOL if you have a breakdown-but using a long truck loading scale reduces the opportunity cost considerably from a cost per ton basis and duty cycle.

your turn ■

Hello,

Pre -Weigh type along with twin leg Flow Control Gate may be the idle solution.

We are the leading supplier for In motion weighing and loading for coal disppathes. You may visit our website www.meritbulkhandling.com and ask you quiries using mail I.D. rajesh@merittech.co.in

Regards

Rajesh

■

Sounds like my idea... ■

Hello,

We have built one system that loads trucks using a short belt conveyor that is fed from a surge bin. The truck driver pulls under the conveyor, swipes an RFID badge, and follows a traffic light. The traffic light changes color to prompt the driver to pull forward. Some of the drivers are precise enough to move with the flow, but most move the truck as prompted.

The system loads a truck to a gross weight of 80,000 lbs. (Net Wt + Tare Wt ). The tare weights vary by truck so the net weight must also vary. In order to load the truck evenly we have photo eyes that make sure the truck is in position. The truck must be moved in order to get the weight evenly distributed over the axles. The belt scale knows how much coal has passed over the belt and trips proportional setpoints. If the truck stops before the next setpoint, the feed shuts down until the truck moves to the next set of photo eyes. The set points are not 25%, 50% and 75%. As the coal starts into the truck some of it is sliding back into the end of the trailer bed. This system loads a truck with about 50,000 lbs of coal in 50 seconds running at a peak rate of 1500 short tons per hour.

Some of the problems we have encountered are the photo eyes must be cleaned periodically. The surge bin going empty giving a variance to the pre-act value. The pre-act is the amount of coal that passes the scale after the gates have closed. The system watches this value to adjust the loads before starting. We have also seen the hydraulic gates react slower in cold weather. This system is not precise enough to be used as a basis of payment. In the US, there are a number of requirments for scales to be Legal for Trade. This system does not meet those requirments. This system is designed to load trucks of a specific length. If the truck is too short, then the photo eye setpoints must be changed.

We have recently been given a task to design another system that will be legal for trade for another location. This next system will use a more precise belt scale. I am working on a positioning system that will use a distance measuring photo eye This will let me measure the truck and also measure the distance the truck moves. Hopefully this will eliminate the number of eyes and give me the flexibilty to load different trucks. ■

Here is a photo

Attachments

amcoal02 (JPG)

■