Re: Upward Gravity Take-Up At Tail
Have seen one on 1800 mm ST1250 (around 15 tonne or so of CWT) running for the last 20 years or so.
Just as you describe one clean, one not so clean bend pulley.
Can be done! Though wouldnt be first choice - though sometimes you are painted into a corner.
Regards,
Lyle ■
Re: Upward Gravity Take-Up At Tail
CDI have designed and seen many with such a configuration. Its used in limited space applications as you note.
You must take care in the arrangement. The take-up mass will likely be placed over the belt and one bend pulley. Some concider this to be unwise. If the belt breaks, one bend pulley and the belt do suffer.
Maybe, a hydraulic take-up with the same pulley arrangement will eliminate the risk of the noted potential damage.
Photos need a PO. Just kidding. ■
Re: Upward Gravity Take-Up At Tail
Can you state why you wish this arrangement. There are other options for the information given? ■
Re: Upward Gravity Take-Up At Tail
Thank you Mr Brown and Mr Nordell for your prompt answers.
The counterweight can be on one side of the conveyor, in a cage, and the tail pulley can be stopped before it hits the bend pulley, so no risk to equipment or personnel in case of belt/wire rope rupture.
There are 2 main reasons for an upward take-up in this appplication. 1) We want to maximize the stacker motion / piles sizes with no back space for horizontal take-up at tail. 2) The head of the yard conveyor cannot raise because the stacker has to roll to the yard limit to feed a following conveyor that needs to be high at the tail.
So like Mr Brown says, I am a bit painted into a corner. If an upward take-up would not be viable, I would put an horizontal take-up at tail, with minimal motion. ■
Re: Upward Gravity Take-Up At Tail
Dear Philippe,
We are recommending the same configuration for a radial stacker on a copper ore conveyor. Tonnage will be about 6000 t/h. The purpose is to reduce pulleys and gain belt alignment on the stacker. The stacker does not luff.
The counterweight moves with the stacker. In your case, I would recommend the same, but place a impact beam above the belt. There is no need for sled plus sheaves, ropes and TUP tower. These introduce hysteresis. Your system will work.
Weight may be an issue for us. If so, then a hydraulic operated TUP will be the option. The hydraulic system can also have a sloped TUP in-line with the stacker or vertical arrangement as noted above.
The physics are the same. Engineering is straight forward. ■
Re: Upward Gravity Take-Up At Tail
Dear Mr. Philippe,
I am yet to think about the upward type of gravity take-up mentioned by you.
Meanwhile, you have another option of using steel cord belt. You have about 300 m long belt conveyor and if you use steel cord belt, the take-up stroke will be just around 0.3% this means about 900 mm basic length of the take-up plus you will have some allowance for erection (vulcanising). In this situation possibly you will have around 1.8 m of stroke, which can be possibly accommodated directly at the tail pulley (as a horizontal gravity take-up at tail end).
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
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 ■
Re: Upward Gravity Take-Up At Tail
Further to my earlier reply, I am adding the following information for readers benefit.
As for the stockyard conveyor, equipped with stacker, generally, the few tenths of meter length gets allocated on the tail end side, as there is concave radius prior to machine tripper. This could be 60 to 80 m length depending upon stacker tripper pulley height (size). Similarly, if stacker has slewing and luffing boom, then one has to see that boom does not collide with the overhead structure of head end, if it is so.
In addition, the stacker has to stack the material from where reclaimer can reclaim the material. Sometimes, it may result in to further reduction of stacker travel length (this depends upon type of reclaimer).
In above situation, it has been observed that generally there is no difficulty for having a space for gravity type take-up. Usually this is horizontal loop type gravity take-up placed, below the conveyor at forward end or rear end. If the conveyor is straight horizontal on ground, then there are many installation with open trench of say 1m depth for the take-up travel zone and for the take-up tower, it is located at nearest convenient space in stock yard. In India at one power station the take-up tower is placed even beyond the receiving cross conveyor. The ropes are carried in a very safe manner by underground covered small trenches.
Finally, designer has varied options to have the take-up arrangement as per his choice.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
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 ■
Re: Upward Gravity Take-Up At Tail
Phillipe..
Could you possibly put a forward pointing take-up at the head end under the downstream conveyor?
LSL Tekpro ■
Re: Upward Gravity Take-Up At Tail
First, thank you all for your replies.
The yard conveyor should remain near ground level, since the stacker has to roll all the way to the the head end. A trench is not desired due to snow conditions. With a steel cord belt, CEMA 5 recommends a 2.1m take-up. Allowing space for carriage and sheaves, an horizontal takeup at tail would use an extra ±3.5m of yard compared to the upward take up. This is important land space fot the client. So I am back to my fisrt question: Is an upward take-up at tail viable? From previous answers, it seems yes. Does anybody ever had bad experience with such take-up?
Sincerely,
Philippe Grenier ■
Re: Upward Gravity Take-Up At Tail
Phillipe
There will be no problem with your tail take-up being vertical.
It's been successfully done before, and is not really an issue.
A take up near the head drive is however better, and that is why I asked:
"Could you possibly put a forward pointing horizontal take-up at the head end under the downstream conveyor?"
I had to sort out a 500m yard conveyor with a head drive and a tail take-up, because the drive slipped on starting.
The dynamic analysis showed that the respose time of the tail gravity take-up was too slow, and had to have significant additional mass.
Yours is only 300m from the drive so will be OK if you limit the start torque nicely.
Bon chance Phillipe..
LSL Tekpro ■
Re: Upward Gravity Take-Up At Tail
Graham,
This solution seems a pity. Adding 3 pulleys to install a gravity take-up at the head end verses fixing the drive slip using a tail take-up is not intuitively positive.
Now you have 5 pulley instead of 2. You have two dirty side contacting pulleys verses zero. This can seriously increase maintenance, increase risk of splice failure, increase risk of belt mis-tracking, and, in general, decrease the conveyor's reliability.
Additionally,we find great benefit in reducing the shock wave action near the loading station using a tail take-up with incline conveyors and conveyors of consequence such as ZISCO's 16 km overland . ■
Re: Upward Gravity Take-Up At Tail
Larry
The minimum number of pulleys for a yard belt with a vertical gravity tail take-up is four.
Also, the minimum number of pulleys for a yard belt with horizontal gravity forward pointing head take-up is four.
So no problem there.
I did not fix the drive slip on the 500m yard belt by putting in a head take-up. I added more mass to the existing tail take-up.
Cheers
LSL Tekpro ■
Re: Upward Gravity Take-Up At Tail
Graham,
You did not answer the point, only the point on the curve which is not the issue. Most often simple yard conveyors have a vertical gravity TUP and do not use sheaves, ropes and towers. Your concept implies a gravity tower. Am I wrong. If I am not then you should also include the sheaves and ropes in an assessment. ■
Re: Upward Gravity Take-Up At Tail
Larry
The thing is that Phillipe is short of space. So he wants to put in a vertical tail take-up with a seperate tower for the counterweight all at the tail end.
All I am suggesting is that he puts the counterweight tower at the head end instead, and hook it up to a forward pointing horizontal take-up immediately behind the head drive.
Same number of pulleys, but a better arrangement.
C'est tres facile n'est pas Phillipe..
LSL Tekpro ■
Re: Upward Gravity Take-Up At Tail
Graham,
A key operative word is "stacker". I don't think Phillipe wishes to install TUP pulleys over the pile. Thus, one of your dual purpose bend pulleys cannot be eliminate.
I am designing for a client the exact tail reversed vertical TUP concept discussed for a copper primary crushed rock stacker. This places the TUP system in easy reach for maintenance which the client is requesting. The new arrangement requires a total of three pulleys. This eliminates one pulley from the present system. It is an existing operating system so the client has knowledge of his gain and loss.
The TUP weight is slightly reduced.
If you want to save the aggravation of the gravity contraption, then use a fixed (hydraulic or screw) style TUP at the tail. This eliminates 3 existing pulleys. This may be his preferred option when all is considered. This is my recommendation. ■
Re: Upward Gravity Take-Up At Tail
It seems, I have started an interesting thread....
To better understand the context, the client want te relocate an existing 37m stacker in a short yard (±300m), so every meter counts!
I attached a sketch showing the upward take-up at tail.
From previous posts, I understand that this is viable, though some cons. I will stick to it.
Philippe Grenier
Attachments
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Re: Upward Gravity Take-Up At Tail
Phillippe,
In principle, you have it right. Please refer to an earlier point, if the cable were to break (highly unlikely but an issue to some) you might think about either a protective beam or chains limiting the free fall.
Based on your configuration, a straight forward calculation of the tail TUP is in order. ■
Upward Gravity Take-Up At Tail
Mr. Grenier,
Your proposed take-up arrangement is quite common for the full length hold conveyors at self unloading ships. The reason is the same, the tail is literally up against the wall. The only difference is that the tensioning is typically by constant pressure hydraulic cylinder rather than a gravity counterweight.
Joe Dos Santos ■
Upward gravity take-up at tail
On a future 914mm x 300m yard conveyor carrying iron ore to a stacker and where land is at premium, I would like to know if it is possible to use an upward gravity take-up, where the tail pulley is pulled upwards by a counterweight. This needs two bend pulleys at the tail, one being on the dirty side of the belt. The use of a take-up at the head is excluded by practical reasons. A picture of such upward take-up would be appreciated. ■