Detection
I would guess that bindicators on a suspended array ..has been used by you ????
We have a Stacker system we currently use to stockpile Bauxite..using the bindicator array we have very reliable stacking times with very little downtime.. ■
Re: Stacking Control
Hi Gibbsy,
U got me there on an array of bindicators - this is an open stockpile.
I was thinking of some scanning device from the tip of the stacker boom.....
Are U at QAL??
Cheers
James ■
Stacking
Yes mate i am at QAL...In the raw materials handling area...
I am refering to our tri hydrate stockpiling facility ■
Re: Stacking Control
Dear Mr. R J Morrish,
Please clarify how are you blending the material. Is this by simultaneous operations of three feed points on single conveyor or are you doing blending in subsequent system?
You have not mentioned anything about effectiveness of blending and hence it is presumed that you are achieving the blending effect to your requirement.
It seems you are only referring to some solution for automatic positioning of the stacker where there is need. Please clarify.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Advisor / Consultant for Bulk Material Handling System & Issues.
Email : parimul@pn2.vsnl.net.in
Tel.: 0091 (0)20 25882916 ■
Re: Stacking Control
Mr Mulani,
We do not need blending, we have very high grade material.
Yr assumption is correct....we need to work out where to move the stacker to next depending upon enough room on the stockpile...this will depend upon recent rill gate reclaiming.
It seems you are only referring to some solution for automatic positioning of the stacker where there is need. Please clarify. >>>Yes
Thanks
James ■
Stacker Problem
Greetings,
It sounds like you will have a simple fix to your mystery.
If you connect a set of mercury tilt switches on a chain out in front of the dump angle of your stacker on a piece of pipe or angle iron at about a thirty degree angle from the center line of the stacker conveyor you will solve your problem.
The only thing you will have to decide and experiment with is the
size of the pile/angle of repose of said limestone.
All that is needed is to tie in the tilt switch to the travel motor control.
1. When the top limit tilt switch is moved by the pile of ore it will tell the travel motor to turn on on and travel in the direction of open air space below the stacker. When the tilt switches return to a neutral or open switch state the stacker tram motor will stop;
all while the stacker conveyor is still delivering product.
2.Tying in the tram motor wiring should be fairly straight forward with out much fuss as it is only one function- assuming you are using remote control, or manual control.
Also you do not state whether you are using 480, 600, 1000 volt, AC or DC or for that matter 50 or 60 cycle AC.
3.Since it is a momentary contact it should cause you no problems as the wiring will only be dedicated to the tram function assuming you are going to be using using 110 volt for the tilt switches.
4.this will be much simpler to use than radar as the radar can and will be distorted by the dust from the product where the tilt switches will not be fooled.
lzaharis "Semper Excellsior" ■
Re: Stacking Control
OK...Thanks for the tips...
We use the stacker for 3 diff. materials.
The main one is for 2 chevron stockpiles. The stacker has 2 pile touch tilt probes and one middle probe for boom lift.
The boom angle varies acc. to pile height for max. blending effect in this case...it also reduces dust generation.
The middle probe controls the boom angle to suit and the 2 pile touch probes stop the travel in case of hitting a stockpile eg ram leak/seal failure.
The middle probe also serves for last layer warning/failure in the event of active when there is no more boom luff available..
For the high grade limestone - we do not need blending. The piles are all in the open air.
We still have the 3 probes on the stacker boom. We would like to lower boom to reduce dust - but not 100% necc. Lowering/raising the boom will mean an added complication for travelling - need to ensure that it will not hit a pile next to it...
Hence - we need to make control decisions on the run ie when unloading trains....ie where to move the stacker to next when the boom angle reaches max..I do not think that a probe on the stacker will do this as it can not sample other areas of the stockpile and make this decisions.
A bindicator array sounds like OK for a bunker situation - need to know more...
Cheers
James Morrish ■
Re: Stacking Control
Mr. Morrish,
I have not given thought in depth, however one of the methods could be as below. Please examine the following possibility for suitability:
1) Divide (mark) the stacker travel in number of segments i.e. segment-1, segment-2, etc in series.
2) In each segment, place the suitable level indicator such as deflection type, or pedal type beyond the range of stacker boom. Such switches can be installed from steel column erected from the stockyard floor. The segment where the level has become low, the switch will give signal at the control panel located either at stockyard end or as the case may be. The operator from control panel can give command for the machine to travel in respective zone.
3) The machine will only travel after fully raising the boom and will travel itself to the segment being commanded.
The automatic positioning system for travelling tripper on bunkers is not uncommon.
However, operations of big machine such as stacker, without attendant on the machine, will it not be hazardous to somebody working nearby? Please look into such safety aspect.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Advisor / Consultant for Bulk Material Handling System & Issues.
Email : parimul@pn2.vsnl.net.in
Tel.: 0091 (0)20 25882916 ■
Re: Stacking Control
OK
We do not really want a device mounted in the pile - as we do not get 100% reclaim due to the rill angles. SO we have to use excavators and FEL's for 100% reclaim when required.
We do not want an operator to move the stacker to the next postion. We have auto operation for the other products. In Aust, there are many stacker and reclaimers operatin in fully auto mode - no operators on machines. It is safe.
Thanks
James ■
Re: Stacking Control
I believe many automated stacking systems utilise ultrasonic transducer systems to track stockpile height. Should be fairly straightforward to programme PLC to control stacker luff and long travel based on directional proximities of material from stacker head. ■
Stacking Automation
James
All our Stacker reclaimers are automated for both reclaiming and stacking functions. The stackers automatically stack into dedicated stockpiles by either cone or windrow stacking method
Automation is achieved by monitoring
* Lontravel position via encoders, and taggged RFI postioning checks (every 100 meters) and laser measureing devices - Thress sources for protection
*Luff angle by inclinometers on the boom
*Slew angle encoders on Boom
*Stockpile position - ultra sonic level dectectors (2 off)
Basically the stacker stacks until the cone is within a cerain distance and long travels to the next positon when it finishes its row it then luffs up travels back to the start of the stockpile and starts a new bench.
Currently the operator sets the boom in position and the rest is automated - some of the machines can auto relocate into the stockpiles but this has not been fully impelmented
Regards
David ■
Pile Height Sensor
Hello: We manufacture a fully PLC operated TELESCOPIC STACKER.
I pile height sensor located at ........a position hanging below the head pulley is tipped when the pile contacts it and causes the stacker to move automatically to left or right or whatever you set the PLC for.
take a look at our website.........www.assinck.com
under the tab TELESCOPIC STACKER for a look see.
HOPE this helps..........George Baker ■
Stacking Control
Hi All,
The stacking and blending forum posts do not seem to come thru, hence, post in the next best forum.
We have a slewing boom stacker which stockpiles 3 diff. materials.
For one of these materials, very high grade limestone, we have a simple reclaim system of three underground rill gates feedign a belt conveyor.
The operation of the rill gates is controlled by PLC based on detection of material on the belt. The stockpiled material flows by gravity to the repose angle thru the rill; gates to the reclaim conveyor.
Depending upon the sequence of the rill gate openings, the "shape" of the stockpile will vary.
The stacker is setup to simply load the stockpile at one position with the boom fully elevated.
This means that we need one operator to move the stacker as the pile reaches the boom tip.
It would be idela to fully auotmate the stacker control to move the stacker along the pile to an area where more material can be placed.
As the shape of the stockpile - cones, valleys etc depends upon the rill gate activity and the stackers, this is not a simple PLC change.
We believe that we need some sort of smart radar system, to scan the stockpile surface to work out where to move the stacker to next to continue loading.
The desired outcomes are ; reduce manpower needs, decrease train unload times by eliminating frequent stops/starts.
Does anyone have ideas or the magic bullet??
Thanks
James ■