Greetings,

What if any repairs or adjustments have been done in the recent past? Did the iron ore feeder start having problems after the repairs or adjustments were made?

Has the delivered size of the iron ore changed recently?

Is the feeder pan level from side to side?

Are the eccentric weights still in their original positions? with all the dust and ore in the photo as shown that tells me that a good cleaning is required first.

If your feeder has a VFD(variable frequency drive has it been reduced(adjusted for a lower speed?)

Has anyone used stroke card to check the feeders feeding length during work?

Is the lip of the feeder banging against the edge of the delivery chute on one or both sides or is the ore free to drop on the take away belt?

If the feeder has become even more unbalanced (from iron ore fines build up) it will have trouble feeding iron ore or any ore for that matter.

Is there an identical motor and weight on the opposite side? perhaps the motor is burnt out-failed and it has not been noticed?

Perhaps the motor shaft has separated from the eccentric?

Has the frame of the feeder been checked for squareness?, to make sure its measurements are equal on all four corners of shaker pan measured diagonally.

Are the weights exposed to the point they could have dust build up on them affecting their operation-it looks like they may have dust in the weight area.

Have the motors been checked for resistance? Does the circuit breaker have to be reset repeatedly during work? Is the wiring to the motors the proper size?

In your photgraph it looks as if there is quite large accumulation of fines in the springs at the left (rear end of feeder)side of the photo.

How often are the springs inspected? do you check them for cracks in the coils? are they checked for proper spring energy due to a weakened(worn) spring coil?

Have the spring tensions in the front of the feeder been changed recently? From the picture it looks as if the spring in the foreground of the picture may be damaged or broken.

Any feeder must be kept clean of any fines build up to operate efficiently. ■

I agree with all the suggestions that lzaharis gave. If none of those work, you might want to think about switching to a two mass feeder design. Here are some benefits you will see with a two-mass feeder...

BENEFITS: Two-Mass over Brute Force

- Two-Mass drive uses significantly less energy than brute force... you would one use one motor instead of two, usually running at around 40% load once the unit is running.

- Impact into equipment is reduced, causing equipment to last longer.

- As load increases, so does conveyability of product.

- Equipment does not bog down and dampen out under load like brute force.

- More stroke can be achieved with less energy with a Two-Mass drive system.

With the additional stroke and the fact that two-mass will compensate for increased loading, your problems should resolve themselves.

Thanks!

Tom Musschoot

General Kinematics Corporation

www.generalkinematics.com ■

I understood from your querry that you are facing problem only during winter when the moisture content goes high. Right?

I assume that the material is sticking on the vibrofeeder pan.

If the pan is worn out this sticking will be aggrevated.

Or you may need to increase the counterweight setting.

You may try using liners which are abrasive resistant and nonsticky.

Please post your reply as soon as the problem is solved.

Mr.Tom : Two mass system is same as mechanical exciter

( Gearbox having two gears having extended shafts fixed with counter weights )? Kindly clarify. ■

Two-Mass refers to a style of vibratory equipment where one mass (an exciter) is used to drive a second mass (trough). The exciter mass typically contains a motor and is connected to a trough using a combination of springs. Combining the two masses and the springs, a resonant frequency can be calculated. When the operating frequency of the motor is close to this calculated natural frequency, the resonance that takes place within the system requires less horsepower to achieve the same amount of work as a single mass (brute force) system. The closer the frequency to the operating speed, the less horsepower required.

Here is a picture of what I am describing...

[IMG] http://68.77.50.106/images/mfeeders.jpg [/IMG] ■

Thank you Mr.Tom ■

Moisture causing problems in the winter:

So.....the unit works fine when no moisture buildup ....which is most of the time

WINTER:

- Seems more eccentric OFFSET of the counterweight system is in fact needed when moisture content rises

- Moisture content rises, FPM travel rate from the feed end to the discharge end......slows down, which increases the bed depth on the feeder, which increases the STATIC load on MR FEEDER, which slows it down....and makes it feed inefficiently.

OTHER OBSERVATIONS:

My buddy Izaharis....hit most and he is right. BUT, these units must be FREE FLOATING, VIBRATING DEVICES. Floating on the coil spring system, without restriction to work properly.

It appears to me in the photo.....excellent pic....that there in fact may be contact (RESTRICTION) of the vibrating body with the discharge chute area....contact would be indicated by knocking noise on start or stop. BUT,

It may be that the vibrating feeder, underside of the discharge lip area or elsewhere is RUBBING....which would slow feeder accelerating force DOWN, cause the feeder to work in FRICTION or RESTRICTION and causes the material to move SLOWLY.

.....................

If moisture in the winter, I assume you are getting CONGLOMERATED LUMPS which could be stalling in the feeder choking between the feeder pan bottom and the underside of MR FEEDER HOOD. (maybe try to stationary scalp in the winter the big stuff)

Try to get some heat into the area somehow.

Izaharis....covered it all pretty good.

I wouldn't mind hearing how you make out. GEORGE ■

Looking to the photo again, I am having two doubts.

1. How do we ensure that the material flow to vibrofeeder receiving area is sufficient, particularly in winter the material will be sticky?

( If the input itself is less for the vibrofeeder, output will also be less. And I think there is no window for inspection to check this.

Guessed from the photo )

2. Have you provided rod gates above the vibrofeeder or is it some other arrangement ? What is their purpose? ■

Greetings and salutations George and Sganesh,

If you look closely in the picture there are shadows and actual legs of other feeders in line with the one in the foreground.

The picture he has posted looks as if it is either cast in place bunker with small disharge holes over each feeder.

He has not mentioned if this is a picture of a stockpile drawpoints below ground level or in an elevated bunker in a smelter building.

The other question that remains is he having trouble with just the feeder in the foreground of the picture or the entire line of feeders in the drawdown area as they appear to be the same manufacture and have the same under bin mounting to the ceiling of the bunker.

Perhaps the ultimate solution to his problem is to spray the ore with an anti-caking agent to improve flow as his drawpoints are very small in size.

I certainly hope he tells us more.

lzaharis ■

Well, with the two mass design, as load increases, so does the stroke increase automatically, eliminating having to change the weights. Two-mass does not dampen down with increased load like you are experiencing with direct drive feeders... that is the beauty of the technology.

Anyway, I have passed the issue along to some of our application engineering specialists and will post their reply as soon as I receive it. ■

Greetings and salutations A. Hashemi, Peace be with you.

1. Stroke card- my friend george can explain it better as it has been many years for me- a stroke card gives the operator the movement distance or orbit of a screen when it is behaving properly or misbehaving badly-meaning the distances the screen travels when working or in the case of an orbital screener the actual orbit-good or bad while working.

A stroke card should be easily obtainable from the supplier but better yet george has a bit of information on how to draw one up also.

A feeder like yours or the allis chalmers feeder I worked on moves very rapidly continously when activated to move and displace material from back to front on pan feeder. with your system the dual ecciters move in the same way due to the weights connected to the motor shafts of both motors and this provides the energy to move the pan forward and the springs restrain the pan to move it back just as the four or more springs would on a pan feeder with a motor and eccentric weight mass mounted on the rear of a pan as was done by Allis Calmers many years ago.

2. The eccentric weights:

The motor has two covers covering the eccentric weights-are they sealed from dirt? meaning can dust enter the eccentric weight area on both ends of the motor-it looks as if the cover for the lower weight may allow dirt to enter as it sits near vertical-the maintenance manual for the pan feeder should show this exactly for you.

Is so you need a supply of compressed air to clean the motors, springs and eccentric weights and to remove the dust off the "entire" frame of the feeders as that is that more weight the entire system has to move in addition to the pan and the iron ore it is feeding.

3. The dust hood over each feeder:

I agree totally with george about the hood over the feeder pan it would or could restrict movement. You should have enough room to lower it as the pan dumps directly on the takeaway belt in the gallery. The side lips( the top edges on all three sides) of the pan will show wear if the lips of the pan are rubbing under the hood.

Be sure to lower it exactly from side to side-using a new aluminum bubble level(or a string bubble level using nylon twine held tightly on the side edges of the pan.

If the clevises or tensioners are rusted to the point they will not turn to adjust them it is time for them to be replaced; be sure to use a thread saving compund such as "never sieze" for example to protect the unexposed threads by brushing it on liberally,able and running the the threaded parts back and forth to completely coat the threads from one end to the other.

4. Putting heat in the drawdown gallery will help a lot with the freezing problem of the ore for sure as the ceiling will act as a thermal mass to the underside of the stockpile

George-I apologise if I missed something.- Just a side thought-do you suppose the reason for the sealed hoods is because of mass flow through the drawpoint resulting in flooding of the pan and hence the reason for the sealed hood over the feeder?

leon ■

Thank you for the feedback Hashemi. Hope you will succeed if you increase the counter weight settings. Please let us know the present setting and setting you increased.

Dear Mr.Izaharis : Please explain more about anticaking agents.

Can we use it for iron ore ( raw material for sponge iron plant ).

Are there any dealers in India?

Suggestion to Moderators: If the stroke cards diagram is available in this forum, we can take a print and use at site.

We can think of diagram of angle of throw also.

If there is any other similar useful tool, we may think that also.

Please reply. ■

Here are some of the suggestions from our applications engineers...

The ore concentrate is frozen during winter if moisture content is high (12% is high). Once lumps form, the flow path would be blocked. A heating element in the feeding area might be helpful.

You should probably first check to see if the moisture content is the same in the summer. If it is and the unit is in a area where material can freeze that’s probably it. If this is a area that doesn’t freeze and the moisture is the issue, maybe a UHMW liner would help. You should also check the feeder stroke from summer to winter. If it’s lower in the winter, hopper revisions could help to reduce restrictions. ■

Here is a stroke card to download

You can print it on a 2x4 " label sticker and place it on the drive to use it.

It is a little difficult to just describe the instructions in a post.

We could create a video and post it to show how it is used to determine stroke if you are interested?

Possibly you already know how it can be used.

Tiffany

JVI Vibratory Equipment

href="http://www.jvivibratoryequipment.com" target="blank">www.jvivibratoryequipment.com

Attachments

stroke card (JPG)

■

1. I would at first try the suggestions of tmusschoot and george in regard to the eccentric weight but be sure the pan can float freely as my friend george has so well described to you.

2. I would also second what george and tmmusschoot have said about heating the drawpoint gallery as your tube is square and the concrete it will create a huge thermal mass to warm the stock pile. By the combining of Georges and tmmusschoot's suggestions you may not have no further problems.

By heating the drawdown gallery you will also reduce the possibility of toxic mold and in turn reduce the moisture that accumulates year round(which increases rusting)-no harm in wanting a dry football pitch year round my friend.

Any reputable chemical supply house on the continent can help you I am sure-I would ask a chemist (in house if you have one)if a solution of calcium chloride would be compatable(non reactive for taconite)for spraying during stockpiling.

lzaharis ■

How is your situation now? ■

if these are electromagnetic type feeders.....you should check for gap in the vibrator to ensure you still have the full STROKE that the manufacturer sent the units out originally with.

You may need to RE-SHIM THE GAP in the vibrator.......which will increase the efficiency of the feeder performance for sure.

CONTACT your manufacturer on procedure....NORMAL thing to do. ■

I went back to RELOOK at the pic.

THESE ARE invicta motor type VIBRATORS.......so my last post .......does not apply...my apologies.

BUT STILL......open the end covers on the motors........and tell us the SETTINGS you are set at.......you may need to set the offset to a bit bigger OFFSET.....to help be more aggressive with the material........those units are in fact adjustable.

Keep Shaking...... ■

Dear Hashemi,

From the threads I have read, I think you need to do a stroke check to confirm how much stroke you are getting out of the unit. You may not be operating the feeder at it's optimal speed and stroke. Ideally, you should be around a 7/16" or 1/2" stroke. You should check the original configuration of the unit to ensure proper adjustments. Typically in the winter months you may need a more aggressive stroke to help break-up that material. Keep in mind that for every 10% faster you run the unit over the factory design, it will result in approximately 50% reduction in bearing life. ■

Geez....advertising your company manufacturing.......is not the purpose of this FORUM.

Pls refrain or we will respectfully BAN your company. THANKS

George Baker MODERATOR. ■

Originally Posted by lzaharis

3. The dust hood over each feeder:

I agree totally with george about the hood over the feeder pan it would or could restrict movement. You should have enough room to lower it as the pan dumps directly on the takeaway belt in the gallery. The side lips( the top edges on all three sides) of the pan will show wear if the lips of the pan are rubbing under the hood.

Be sure to lower it exactly from side to side-using a new aluminum bubble level(or a string bubble level using nylon twine held tightly on the side edges of the pan.

George-I apologise if I missed something.- Just a side thought-do you suppose the reason for the sealed hoods is because of mass flow through the drawpoint resulting in flooding of the pan and hence the reason for the sealed hood over the feeder?

leon

Dear lzaharis,

do you have any picture shows proper hood installation on vibrating feeder?

I would like to design a chute for discharging iron ore from a vibrating feeder to a belt conveyor very similar to this thread.

would you please inform me:

1- reference for chute design. do you have any recommendation?

2- reference for suction hood and required flow rate for ventilation. do you have any recommendation for flow rate value?

3- I should install hood on vibrating feeder(how?) or we can pose it on the chute

4- as the tunnel is very narrow(the roof is very low) do you have any experience or suggestion for ducting?

5- I have read all your suggestions and I would like to consider all parameters in my design to prevent future malfunction.

thanks for your guidance ■