Tripping Of Boom Conveyor While Stacking
Tripping of Boom Conveyor while Stacking
For a Bucket wheel type Stacker Reclaimer,the Boom Conveyor trips when the stacking is at height of 8mtrs above and when the feed rate on the belt crosses 2800 tph though the system was designed to handle 3600 tph.The Boom conveyor is tail driven and having hydraulic jack operated screw take up arrangement.Can any one suggest feasible solution to this type of problems. ■
Trip To Go
Pls. give some detail as:
- Reason for trip (motor current, motor thermistor, electric supply system, gearbox oil temperature, others)
- Are you in commissioning stage or is this a new problem? Did occur a change in the bulk material or its properties?
- Is this a selective problem without warnings, or does it develop towards said limit of 75% nominal throughput?
Regards
R. ■
Eight Metres Above Where?
Are we talking about stacking or reclaiming?
Have you explored any of Roland's possiblities, you should have done this first. It is not reasonable to highlight a problem without giving insight in the first place; no matter what you have seen on several previous threads. Miracles to order; the impossible takes a little longer.
On first viewing, the problem seems to be that you have bought a cat in a bag. Have you approached this manufacturer?
Look at it this way: how did you work out that 2800th-1 was the stall load in then first place? If the machine was designed to carry 3600th-1 then shouldn't you have tried it out at this load at commissioning and then had to dig the belt out so that it could restart at a progressively lesser figure?
It doesn't really matter where the fancy take up arrangement is located but if it is active then perhaps the feedback signal is incorrect and you are pushing when you should be pulling. The possibilities are endless with this sort of open ended question. ■
Re: Tripping Of Boom Conveyor While Stacking
Originally Posted by Roland Heilmann
- Reason for trip (motor current, motor thermistor, electric supply system, gearbox oil temperature, others)
- Are you in commissioning stage or is this a new problem? Did occur a change in the bulk material or its properties?
- Is this a selective problem without warnings, or does it develop towards said limit of 75% nominal throughput?
Regards
R.
Dear Mr.Roland,
The problem is faced while stacking the Oxide pellets in the yard using Bucket Wheet type Stacker cum Reclaimer.
When there is suddern discharge of material on to the Boom conveyor,the belt on the drive pulley(Tail drive) is slippinjg and the belt trips on ZSS.
The only provision was to adjust the Hydraulic jack operated Screw take up.
This is in Operation and it was commissioned 2 years back.
Can you suggest any alternative to prevent tripping of the Boom Conveyor belt while stacking of the Oxide pellets.
Regards,
Srinivas ■
Live With It!
Originally Posted by louispanjang....On first viewing, the problem seems to be that you have bought a cat in a bag. Have you approached this manufacturer?
......
On second viewing the answer is still the same. It doesn't do what it says on the box. However, since you have been content with the machine for 2 years I suggest you live with it. Any change might be for the worse. For instance, what is a sudden discharge onto the boom. Either you take a full belt or you don't. Sorry to make it sound simple but that's because it is.
Was there any financial incentive involved in supplying a machine which couldn't do the job? It seems as likely reason as any. Your commissioning went straight out of the window, after all. These things happen. ■
Untitled
Originally Posted by tsvas67The problem is faced while stacking the Oxide pellets in the yard using Bucket Wheet type Stacker cum Reclaimer.
When there is suddern discharge of material on to the Boom conveyor,the belt on the drive pulley(Tail drive) is slippinjg and the belt trips on ZSS.
The only provision was to adjust the Hydraulic jack operated Screw take up.
This is in Operation and it was commissioned 2 years back.
Can you suggest any alternative to prevent tripping of the Boom Conveyor belt while stacking of the Oxide pellets.
Regards,
Srinivas
Dear Sir,
Can you suggest any modifications in the drive of BoomConveyor or in the take up arrrangement to prevent slipping of the drive pulley as it is tail drive while stacking mode.
Regards,
Srinivas ■
Miss Behaving Bwsr
Louis in illustrating the cat in the bag phenomina is very well put with this issue.
The one thing you have not mentioned is whether you have replaced the
circuit breaker for the stacker reclaimers boom conveyor.
With duty cycle and amperage loadings the 2 fine adjustments may be beyond
any hope of maintaining the circuit breakers ground fault protection and thus
it dies on you while under load.
But then again if the circuit breaker is in good condition it may be that a simple adjustment
is all that is needed-and in saying that-
When was the last time any belt was taken out of the single flight of belt on the stacker? The belt
may simply be tired and stretched and ready for retirement. If the belt is stretched it may be too weak and then
it will stall simply from loading.
Shrodingers Cat strikes again!! ■
Clear View On Site
Dear Mr. Srinivas,
pls. understand the above mentioned opinions, that the complextity of influences (electrical issues as e-supply and equipment, mechanical issues as belt wear and take-up device function, control issues as tripping limits) cannot be fully assessed from afar. If not available from own maintenance staff, pls. consider the consultation of an engineer specialized in conveyor maintenance.
However, as the system was correctly working two years and does now not cover limit operational conditions anymore, pls. check on boundary conditions as:
- Belt take-up within correct limits as per design drawings (take-up position)
--> Hint as to tired belt issue, if take-up is on limit already. Check on belt condition, consider shortenting / replacement in due time.
- Loading conditions within specified limits, check on inflow of material (wagon tippler, bunker discharge, ...?)
--> Consider decrease of inflow in order to maintain operation, at least for the higher load-out positions. There the power requirements re belt tensions will be highest and thus slipping most probable.
- Did any major changes occur as to the point in time, when the problems begun (throughput increase, change of bulk to higher density or moisture content)
--> This you can only counteract by trial and error tests on lower throughput
But finally it comes down to your decision: Involve someone with know-how on site, and not to risk the operation of the plant.
Two years working seems to be a good timing for a thorough checkup.
Regards
R. ■
Re: Tripping Of Boom Conveyor While Stacking
Hello T. Srinivas,
Tripping (stopping) of boom conveyor
This can occur by following reasons, as a general rule:
1) Dead tension (take-up tension setting) is not adequate. So under higher load condition, the belt slips on drive pulley, and consequently zero speed switch (belt monitoring switch) signal will trip the conveyor.
2) Motor is getting overloaded with respect to its rating and safety current sensors trip the motor. It is presumed that the motor is of adequate size.
3) Zero speed switch operation is faulty, and trips the conveyor unnecessarily.
Boom luffing difficulty
1) Check hydraulic system pressure adequacy as per operational manual, valve function faulty. Whether it is due for service (if old machine). It is presumed that hydraulic system is of adequate size.
2) Whether actually placed counter weight mass is as per design for fair balancing of boom.
3) Refer machine supplier who is the right authority to find solutions and remedial measures.
Regards,
Ishwar G. Mulani
Author of Book : Engineering Science And Application Design For Belt Conveyors (new print November, 2012)
Author of Book : Belt Feeder Design And Hopper Bin Silo
Advisor / Consultant for Bulk Material Handling System & Issues.
Pune, India.
Tel.: 0091 (0)20 25871916
Email: conveyor.ishwar.mulani@gmail.com
Website: www.conveyor.ishwarmulani.com ■
Re: Tripping Of Boom Conveyor While Stacking
Hello T. Srinivas,
Your same query appears in your posting dated 15th March, 2013, where I have put my views.
Regards,
Ishwar G. Mulani
Author of Book : Engineering Science And Application Design For Belt Conveyors (new print November, 2012)
Author of Book : Belt Feeder Design And Hopper Bin Silo
Advisor / Consultant for Bulk Material Handling System & Issues.
Pune, India.
Tel.: 0091 (0)20 25871916
Email: conveyor.ishwar.mulani@gmail.com
Website: www.conveyor.ishwarmulani.com ■
Better Chutes For Stackers
It may be due to pile up of material in the chute with poor chute geometry. The more rounded pellets can not be evacuated within the skirtboard system when the pellets are not accelerated in a forward motion as they drop. A drop in local velocity will cause a build-up and much higher friction against the belt.
Higher tonnage, and higher lufting angle are in keeping with an increase in build-up of material
A drawing of the chute would be telling.
This phenomenon and consequential drag can be analyzed with a good DEM model that resolves the belt line power due to the above action. CDI has evaluated pellet granular dynamics at transfer chutes and provided successful corrective action to poor chute geometries. ■
Poor Stacker Performance - Due To Poor Chute Geometry???
As I answered in your other thread, I suspect the stacker feed chute may be the culprit. The rounded particles tend to rotate as they enter the belt take-away zone in the skirt system. This rotation causes the material to exchange and consume kinetic energy from vertical and horizontal velocity into angular spin. Net result is slowing of pellets and build-up of material in chute and on belt that causes much higher drag on belt.
If this hypothesis is correct, the corrective action is to redesign the feed chute where the vertical velocity is directed into belt line velocity and which minimizes particle spin. We have performed such design changes with pellet materials using our ROCKY DEM code.
Pellet geoemtry needs to be correctly configured. Too round and your created to much spin. To angular and you get too little. A photo of the particle set would allow the distribution of particle geometry to be captured.
CDI can demonstrate this using our ROCKY DEM granular dynamics code. You give me the chute geometry. CDI models the chute and determines the change in material build-up, the higher level of power required, the potential for drive slip, with your present design and then with a proposed alternative. If we cannot fix the problem, we will not charge you for the service. If we do fix it, we will advise of the time and resources. You will receive both cause and effect results of old and new, knowing what improvement in chute geometry is required. ■
Tripping of Boom Conveyor while Stacking
Tripping of Boom Conveyor while stacking I/O pellets using BW type Stacker Reclaimer
Dear Friends,
We have Bucket wheel type Stacker Reclaimer for Stacking and Reclaiming of Oxide pellets.
We have been facing problem with tripping of Boom Conveyor while Stacking Oxide pellets at the time of Unloading of the Vessel.
Luffing of the Boom is becoming difficult while stacking is at the max.height of the stock pile when the discharge rate on the belt is above 2500tph though the system was designed for 3600 tph.
Boom Conveyor belt width is 1600mm ,Motor is 132KW,Drive and Non drive pulleys are 800mm dia ,Hydraulic jack operated Screw take up.
Can any one suggest some feasiblel solution for the above problems so that the Stacking route will be smooth while Unloading of the vessel with minimum stoppage hours.
Thanks and Regards,
T. Srinivas ■