Originally Posted by ndprsha

I acquired a piece of equipment that was originally for a customer but it didnt meet their requirements so we decided to keep it and try to use it in our facility. It is a "Z" elevator originally designed to move dried dates. My task was to improve its ability to load our ovens. The biggest issue with loading our ovens with this elevator was the roughly 3' drop from the discharge to the top of our belt. I have addressed that issue with a little help from this forum and it seems to be working great. The only hiccup in my plans is the vibratory motor that is mounted to the large pan (see photo) is putting too much energy into the pan itself and causing it to deform. Basically, with how things are setup now, at the discharge end the whole pan is warping so much so that it interferes with the discharge of the material. After doing some more research on the methodology of vibratory conveyors, I am rethinking the orientation and placement of the motor. Instead of placing the spinning weights perpendicular to the direction of flow (my original intent with this was to increase spreading in the pan), place them in line with the direction of flow (to cause the particles to jump forward more rather than spread out). I was also thinking about angling the motor so that it would be at a 45 deg angle with the pan to increase energy transfer. Finally, I read with suspension vibratory equipment that it should always be counterbalanced. Are all of these good ideas?

I am rather unfamiliar with vibratory equipment and would appreciate any help on this problem. My original goals were to be able to take material from the "z" elevator, roughly 2' wide discharge, and put them onto our 4' wide belt with a relatively uniform bed depth. Both the elevator and the vibratory motor are on VFDs and that was how I planned to do the fine tuning of this equipment. The weights in the motor are also adjustable and set very low right now.

I am sure my buddy George Baker will comment on this too,

but you have to much force being transmitted by the feeder

I would reduce the weights to an absolute minumum and

slow down the the VFD after that and experiment with the

weights after you have slowed the motor down.

A very small motor with an eccentric wieght can move with tremendous force.

You feeder pan should not bend under any circumstance!

I think you have a issue with the motor speed and the weights more than anything.

NOW as the feeder pan has been bent by the G forces created it is no longer balanced and

has to be either repaired or replaced.

If thay pan is bent the it is not very thick and it does not weigh enough by itself.

Changing the position of the motor is also a no no because the transmission of the forces will be linear.

can you install a V baffle above the feeder to force the dates to the side and then let them migrate across the feeder

after they pass the baffle? ■

Your suspension cables are stiff and need to have a spring installed in each one. Either an extension spring in the suspension set or a compression spring at the top side of the elevator connections. ■

Sorry I missed that Gary. Twas late and I was cold HAHA.

How are things in the center of the polar vortex???

We were at five below last night when I last fed the

coal boiler at 2AM

I wonder if they ever had springs on it to begin with? ■

Yes in a deep freeze here also with blizzard like conditions - chill factor is around -38 deg C. All roads around my home town are closed until the wind dies down. They took the plows off the roads as they were drifting back in as fast as they went through. ■

Originally Posted by ndprsha

Ok,

Thanks Gary and Leon.

I will play with the weights but they are already at around 40 lbs (10%of total) and the pan alone weighs around 100 lbs. I also only ran the VFD to about 30 Hz I guess I should have mentioned that I only tested this with a very small amount of product. If I retried the tests with a larger amount of product should I expect radically different results?

I also take it that by adding in the springs I am effectively counterbalancing the system? When I get springs should I get slightly sub-resonant tuned springs?

From what you see though, the motor location and mounting looks appropriate? No need to bother moving it or changing how it mounts to the pan?

What about possibly reinforcing the pan? Its made of 11 ga SS and is roughly 43" square.

Do not change anything about the motor location!!!!

reinforcing the pan will change the balance "if it was ever balanced"-not good

NOW the pan feeder should always behave whether it is empty, lightly loaded or fully loaded.

Do you have room to use a stroke check card in that mess???? you can down load the file to

print one out and transfer it to cardboard and attach it to the pan at the bottom corners.

The support cables need to be replaced with the proper length cables in relation

to the length of the 4 springs actual length

you can use small diameter wire rope to do this easily as long as the 2 rear pieces are the same length and the two front pieces are the same length to have a true horizontal Y axis

The other thing that MUST be correct is the length of the cables, they have to be exact or the whole algebra problem becomes impossible.

YOU need a bubble level across the top edge and the bottom edge when you adjust the springs with the wire rope before securing the wire rope clamps.

You need to have small diameter wire rope and at least four wire rope clamps at each corner to secure the wire rope to the springs and the upper mounts.

The pan HAS to be level from side to side at the top and at the bottom!!!!

The way it is set up now the pan is not isolated in any way!!!!!! and the forces are

simply being transmitted to every point rather than being contained at the pan. ■

As mentioned in the original thread the stroke should not exceed half a date diameter. To achieve/improve lateral spread you could try a pneumatic vibrator with the axis vertical. They are dirt cheap and can be controlled from the utility air. There is no need for instrument air. I used to make them by getting an old bearing and discarding all except one ball. There is a proprietary air vibrator advertising somewhere on this website if you shy away from making your own (which you seem well capable of doing so far).

We take note of your position. You have taken previous advice on board and got on with the job.

To further improve spread you can profile the downcoming chute as a convex cone sector. (Courtesy of Designer.) ■

Originally Posted by ndprsha

Im hearing that there is too much force being transmitted to the pan. When I originally asked this question I had set the weights to 40 lbs and was running about 30 Hz(~900 RPM). Leon suggested slowing down the VFD and decreasing the weights. I tried this using using 0-30 Hz and 0-40 lbs of weight and had little success getting movement from my test pieces. The pieces being used for test are walnut pieces ~.25" in diameter. This machine will probably not run prunes again but we would like to use it for a variety of commodities like rice and nuts. I understand that the weights and frequency should be tweaked to each different commodity. I am also using an OLI MVE 400/4 vibrator, which is rather heavy and was salvaged from another project. Could getting a more appropriately sized motor help?

Now to the pan. I had this pan made at a local machine shop. I knew it had to be stiff, but did not think balance would be an issue if symmetrical. Im hearing that the pan should never bend and if it is bent then it needs to be repaired/replaced. The pan does not have a bend in it normally, only under load from the vibrator does it bend and this is localized to the discharge. I was thinking of having some pieces welded on the bottom to stiffen the pan, is this acceptable? The motor is also mounted 1/3 the length of the pan off the infeed of the pan. If I do need to check the balance/balance the pan do you have any recommendations on methods or tolerances?

Leon said changing the motor position is a no no because transmission of the force is linear. If I understand this correctly, you are saying that the force from the spinning weights is directed in a straight line. I read in a Kinergy Driven Vibrating Conveyor PDF that if the direction of force is 45 degrees off the direction of material flow then you get the most conveying speed. As it appears that I have none or very little, I thought this could help get material moving through the pan.

Gary and Leon have both said that the wire rope holding the pan needs springs added. I have read that on counterbalanced conveyors the springs should be underdamped, is this true? If so, any recommendations as to how far? Leon also suggested I replace the wire rope shown (3/16" 304 SS) with smaller cables that are the proper length. Is 3/16" too big? Is using turnbuckles not acceptable for fine adjustment as long as they are roughly in the same place along the axis of the wire rope?

Leon suggested putting a stroke card on it. I can do that but didnt find anything from a quick google search. Do you have any recommendations as to where to look or what to search for (I tried stroke card vibratory conveyor and combinations of that and didnt find anything). Currently the pan has no restrictions in the X Y horizontal plane. I thought that the orientation of the spinning weights would largely impart vibration in one direction. If I do need to add mounts to restrict movement, should the placement of these devices be influenced by the location of the motor? Could springs work here as well, or would a rubber mount or scotchply be better?

Leon suggested I bubble level the front and back of the pan to ensure it is level. I have done this and the front and back is level, yet there is a tension issue on one of the corners that I have not yet resolved. The rope lengths are equla and the mount points symmetric but one corner is notably more confined.

Leon also suggested I use wire clamps. I am currently using swagings for safety. Is wire clamps acceptable if this is going to be in an area where people might have their feet under the pan? Do you advise using clips instead of swagings so you can do away with the turnbuckles?

I would like to thank all three of you for helping me with this and look forward to your feedback.

Nick

now that I know more:

1. you need a vibrator properly sized for the pan and the loading

a. it explains the bent feeder pan for sure

b. new pan and smaller vibrator

Changing the motor to a smaller motor may cause the motor to fail simply because the frame size

may not match a smaller motor.

2. a small air powered vibrating beast would work

3. reusing the old pan may be a huge problem simply because the steel is now distorted :^((

4. you need to isolate the feeder pan. The wire is transmitting the forces generated rather

than simply carrying the load and isolating the transmission of the forces created by the feeder.

NOW:

Perhaps using four good heavy screen door springs will work well for you.

Using good wire rope/cable 3/16 should be fine.

At each corner of the upper mount you would anchor the wire rope with 2 wire rope clamps on each corner

using four shackles.

Use a wrench/spanner NOT a nut driver to tighten the wire rope clamps!!!

NOW to the lower portion;

At the four corners of the feeder pan I would use four small shackles and then use four screen door springs

to separate the pan from frame to isolate the forces.

I would then secure the wire rope with two more wire rope clamps at each corner making sure the wire

rope clamps are mounted the same way-the rule is "never saddle a dead horse". ■

Originally Posted by ndprsha

href="showthread.php?p=81579#post81579" rel="nofollow">

Leon,

Thanks for the reply.

I still dont understand why I need a whole new pan if there is no lasting defomation (ie when the motor is off all sides of the pan are flat). Also, is there any information out there to help me "size the pan and motor"? Is there a book that you could recommend?

I assume that you are still recommending the wire rope clamps because they are reliable enough to suspend this equipment over peoples feet. If I understand you correctly on each wire rope there should be two clamps at the top and two at the bottom, then attach it with a shackle on either end.

I will work on ideas to limit the motion of the pan.

------------------------------------------------------------------------------------------------------------------------------------------------

Greetings from 1,140 feet above mean sea level in the frozen eastern wilderness,

We all want you to succeed nick not fail.

it seams that the vibrator is too large.

The pan needs to be replaced Nick because

the pan is deforming due to the vibrators

operation and it is flexing.

I wish I could be more helpfull.

I have attached a stroke card here for your use.

href="https://forum.bulk-online.com/attachment.php?attachmentid=38240&d=1389365195" title="Name: stroke check card.pdfViews: 107Size: 519.1 KB">stroke check card.pdf ■

Originally Posted by ndprsha

Thanks Leon,

Before you mentioned that I might be able to repair the pan. I have some ideas on stiffening the pan. If I am trying to be economical, is it worthwhile to remedy the situation or start over?

Thanks for the stroke card, I will test it out today.

Something like this

Namaskar,

I would not want to repair or use the old pan

because of the damage inflicted already.

I would have a heavier pan made and use that one

and an air vibrator as john has mentioned.

Do you have access to food grade paint or plastic slick sheet material?

I will let you in on a secret,

Take a big full pail of dates and lift it to your waist and pour it out in one motion.

when the pile settles and stops moving that is the angle of feeding you want

checking it with a protractor.

Its an old Tyler screen method and it works, drives me nuts but it works. ■

Originally Posted by ndprsha

Leon,

I do have access to food grade material I have about a 4'x8'x1" piece of food grade HDPE. Why do you ask?

If you can find a thinner piece you can line the bottom of the pan and it will make it easier to make the material flow

But if all else fails you can bolt it to the pan with flat head stainless steel bolts.

The best way to check is just pour some of the dates of whatever else you are feed to see how easily it falls out/down with the sheet at an angle perhaps 21 degrees? ■