Crane ?
Assuming you have conveyors that run 350 tons per hour why dont you consider an equation where the unloading is done round the clock? with a conveyor that is run 24 hours you will move 12000 ton every 24 hours/with out breakdowns.
as this would make the most economic sense assuming they are being charged for mooring time by the ships owner-remember that when that ship is in port it is not out carrying another cargo some where else.
Perhaps the real problem is operations and this needs to be examined?
Do not forget that once you unload it you still have to move it an perhaps utilising a small bucket wheel excavator reclaimer is the way to go to eliminate the cranes. A small one could be utilised and run round the clock untill the ship is off loaded and be better utilised with less first cost.
You have not even told us what type of ship is being used for off loading cargoes inbound, or if the cranes are using grab buckets etc., or the depth of the harbor in question.
You should look at a bucket wheel reclaimer in tandem with a crane as you inbound ores are not sensitive to sizing damage.
The cranes could be rebuilt one at a time and used in tandem with the bucket wheel reclaimer by connecting it to the inbound conveyor. not knowing the harbor/port configuration is also a problem as to sizing.
Ultimately the self unloader is king for any port but size and draft is the key. as this may be your least costly method as it could unload where ever it is needed and with little effort since your conveyor is still intact. ■
Level Luffing Vs Gantry Crane
Dear Sir .
Our company is a well knoun consultant in ports and cranes in Chile South America, we would like to help you as well.
Please contact Us
acfa.consultores.limitada@gmail.com
Thanks. ■
Re: Level Luffing V/S Gantry Crane
Hi Izaharis:
Thanks for your advice, however the port wants to renovate the crane because the boom of the crane is not enough with a very high impact on efficiency.
I got some additional information. The ships are mainly unloaded and correspond to Handy type DWT ¨=40000 ton ; B=40m; LOA=220m; D=10-12 m app.
The conveyor belt was recently updated and it reaches a capacity over the 500 ton/hr.
The common sense says that a gantry crane should be use to increase the efficiency, but the supply time, the flexibility and the cost are much better if we consider a Lever luffing crane.........
Any advice or suggestion........ ■
Crane Etc.
ok my question is this, what are you using now and are you leaning toward a bucket elevator mounted on a crane boom to a secondary conveyor to feed the conveyor on the jetty?
A vacuum unloader would be a lot less hassle and cost less money with a lot less maintenance as you would feed a central deceleration cone over the conveyor.
A skid loader or small dozer lowered in to the hold feeding a hopper would be more than enough with several vacuum lines bringing removing material. In addition to the above you would have a lot less material to clean up and less materal lost.
your turn ■
Re: Level Luffing V/S Gantry Crane
This is a very straightforward level luffing crane application.
You need to examine the mobility of the receiving hopper; or perhaps even provide another one to load trucks covering the present 300tph shortfall. If the conveyor has been upgraded to 500tph how are you going to put 800tph on it? Truck the extra 300tph away using a mobile truck loading hopper. Otherwise the cash that went into the little conveyor is going to look like a big white elephant. You can save the clients face by proposing the mobile hopper as a standby unit.
But you still need the level luffing cranes. ■
John Gateley johngateley@hotmail.com www.the-credible-bulk.com
Re: Level Luffing V/S Gantry Crane
You are right about the effectiveness of a vacuum system however, what about flexibility? And moreover how will load cargo for export?
Presently the port is using 2 gantry cranes, but one has to be updated because of boom reach and height. Then, what is more suitable a level luffing or another gantry?. Don’t you miss the fact that a gantry is already there.
It seems the conveyor belt can be speeded up a little bit more and for export cargo only trucks are required.
If some extra cargo can't be unloaded through the belt, then the trucks and mobile hopper coming into the solution, but still the decision is... another gantry or a level luffing?
Besides that information, the port will increase their through put to over 9 mill ton in the coming years (2011), only bulk. For that, they have to extend the jetty and add 2 new berths, plus some other crane.
That is important information that can affect the decision about the type of crane they need to buy right now. ■
Gantry Crane Or Portal Crane
Dear Sir.
I was reading the complete mailing writing about the issue in the forum.
In my personal opinion, from operation point of view, the complete theoretical model efficiency depends mainly in the volume of load for import and how many tons are for export; also the nature of the products will be exported. (Bulk, container, pallets)
I presume that the percentage of tons for export will be less than import tonnage, and also the goods will be not containers, in that specific case I agree to buy a new level luffing crane, it should be located in the first portion of your berth corridor (land Side), then you will be able to handle steel products for export (and if your berth is long enough) same time you can also unload bulk materials with the upgraded portal crane and the complete conveyor systems. (Of course assuming your berth is long enough to receive two cape size or handyman ships).
Any way the unloading process is not same speed during all the time, once you start the unloading process you will have the conveyor a little congested because all the material you have working will be cream (it means easy to be move) in that time sure you will need also trucks working to move more tonnes out the berth area.
If the level luffing crane is big enough, you can work most of the time with the level luffing crane unloading cream, and using the portal cranes to work simultaneously finishing some others ship hatches or finishing the second ship moored.
Of course the ship owner some times will stop you to work in parallel on the ship because their own ship ballast. (Remember you are in South America and the ships are not the latest design).
In the middle we can give you a lot of ideas, some of them cam help and others can be unseals, we have to see the terminal lay out, dimensions and berth facilities to talk in same way.
We would like to help you, send us pictures.
Bye. ■
Re: Level Luffing V/S Gantry Crane
Hi.
First I would like to thank you for all the valuable information received until now.
I still have some more specific questions:
Is the rail system of gantry cranes different from some Level luffing systems?. Do those types of cranes have different needs from a support point of view?. Are the loads over the wharf similar?.
Regarding the space requirement, Is it possible that a gantry crane work together with a LLC?. Any risk of collisions? (Handy size of ship, 5 hatches, 40.000 DWT)
What about maintenance of those types of cranes. Are the cables of a Level luffing crane the reason of many maintenance problems as some people say?, Are the maintenance cost on a coal environment too expensive?.
Finally how much goes down the performance of some of these types of cranes, comparing iron ore, coal, limestone, petcoke and manganese?
Thanks again for any kind of answer to this bunch of questions ■
Questions About Wire Rope
wire rope in motion requires inspection!,
inspection!, Inspection!, it also reqiures oiling!, it also requires
oiling!, it also requires oiling! wire rope sheaves wound in any sheave width "CAN NOT BE OVER LOOKED in regard to maintenance relating to oiling wire rope, inspecting broken strands and wire rope cross sections where possible.which is usually done at rope replacement intervals. The sheave must be inspected and replaced when needed when wire is replaced for bearing condition and sheave depth for cable diameter as this will affect cable life and cable radius where if the cable is forced to attain a smaller radius it will break.
Loading multiplle products will affect over all wire rope length, and streching generally reducing its life span depending on how heavy a wire rope you buy which is the determining factor.
The material handled will always affect performance of the types of handling system
The risk of collisions is always posisble as far as having equipment in close quarters.
Maintenance is required and cannot be over looked with out consequense-cable failure, motor failure. gear box failure, chain drive and chain failure.
LLC require a good foundation just like wheeled cranes, if you cannot provide it you will have more trouble than you can cope with as GROUND FAILURE BELOW THE CRANES WILL SET YOU BACK FOR A LONG TIME! ■
Level luffing v/s Gantry crane
Hello everybody:
I had been recently commissioned to asses a local port in South America to upgrade there cranes. The port wants to compare the convenience between a level luffing crane or a gantry crane.
That's why I would like to ask you all about information, experience, costs, and recommendations regarding each type of crane, specially about some other ports experiences.
The port is a medium size port, it serve a steel manufacturer. They mainly import coal and limestone and export some residual products (excoriate???? ). They have some very old gantry cranes with performance and height problems. The jetty is connected to the yard through a conveyor belt for import and by truck for export.
The idea is to increase the performance of the loading/unloding system from 500 ton/h to at least 800 ton/h. In average today they unload a ship on 3,5 days and they need to reduce that to 2 days...
If anybody have some valuable information and some comments, please don’t hesitate on participate.
Thanks to all¡¡¡¡ ■