Screens seem to be cracking up regularly these days. It sounds like your holes are on the load line. Holes are themselves stress raisers. What other gearbox mounts are there. Two holes is precious little to hold a drive on a screen. Send a picture of the happy machine. ■

sounds like some GUSSETTING may be in order possibly. The pic will definitely help us along with the answer. ■

This is the engineered accelerating force that a vibrating screen is designed for............which allows the box to vibrate and screen at a given force depending on the size of the stroke and the speed at which we run with that STROKE..... OR THROW.

If we put in a LARGE STROKE........and run too FAST........we break the machine....as it runs over the design limit for which it should.

here is a little cheat sheet I use for year on G FORCES. ■

VSMA the vibrating screen manufacturers association will have this type of book and information.

FIND LINK in previous posts on this forum.

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

overloading: BY the VSMA rules .......it states we do not want to see material BED or mat depth on a vibrating screen ....MORE THAN 3 times the size of the opening in the wirecloth....this is measuring at the discharge end of the length of the screenbox.

IF TOO DEEP - INDICATES an overload situtation....inefficient screening of your material, decreased probability of passing the fines thru the openings.

CHECK PREVIOUS posts in this forum.....well documented ■

We have used this type of oil and grease lubricants, typically when EP RATED extreme pressure greases and oil are under duress.

EP rated lubes have min max operating temperatures. If we have a bearing going or IFFY or in real hot, or real cold temp extremes.....we will recommend SYNTHETIC.....as they have very wide OPERATIING TEMP ranges as an added major value added benefit. YES MORE EXPENSIVE....but, if you need it...

SCREENERS with big bearings and heavy operating body weights do need help from OIL COOLERS, AUTO LUBE SYSTEMS, RECIRCULATING SYSTEMS at times to keep the B10 bearing life in hours UP where it should be.

REAL HOT or REAL COLD or REAL hard to get at places....makes SYNTHETICS are logical sometimes only choice.

Happy Viscosity to all....... ■

Nitesh

Looks like your beam is not strong enough and needs to be redesigned - the temporary solution is to drop the "g" force as low as possible from the process point of view before you can fix the beam. I could have a look at the beam - would need 2-3 days to come up with the solution

Regards

Ziggy ■

Dear all,

When I faced a similar situation, I was given the feed backs as follow.

The exciter was recently reconditioned by the supplier by himself and fixed back with the screen. Within 24 hours, the beam developed the crack.

1. No hitting of vibrating body with the stationary structure.

2. No looseness of exciter fixing bolts with the cross beam.

3. No jamming at receiving or discharge chute.

4. All the four counterweight masses were measured. All are having uniform counter weight.

Requesting any additional cause, which can lead to cracking of vibroscreen cross beam , on which this single exiter is fixed.

Thanks & regards to all. ■

Dear Mr. Ganesh,

There might be a lot of other reasons too. Check for the springs, the screening media( if it is fastened well or not, ) the water level of the m/c, correct feeding of the machine( the feeding point I mean),The R.P.M. with which the m/c is being run ( is there any change in pulley's?), Spline of the cardon shaft( if it is being used) being greased or not?

Hemant Kumar ■

Originally Posted by sganesh

Dear all,

When I faced a similar situation, I was given the feed backs as follow.

The exciter was recently reconditioned by the supplier by himself and fixed back with the screen. Within 24 hours, the beam developed the crack.

1. No hitting of vibrating body with the stationary structure.

2. No looseness of exciter fixing bolts with the cross beam.

3. No jamming at receiving or discharge chute.

4. All the four counterweight masses were measured. All are having uniform counter weight.

Requesting any additional cause, which can lead to cracking of vibroscreen cross beam , on which this single exiter is fixed.

Thanks & regards to all.

The only possible item that is left is the metal of cross beam;

either it is:

1. Too thin

2. Too soft/weak

3. inadequate bracing/not made of properly cast channel iron

4. inadequate bolt type, washers, torquing

5. warped steel weldment

6. Too wide with no bracing weldments/gussets ■

I saw an amusing cause of impact damage where the deck fixings were inadequate.

In RAK I was given Turkish made screens as OEM, before I was engaged.

First the sides cracked within 6mm of the chalk line I had drawn while they were still on the delivery truck.

Once installed; the deck plates slid about a bit because the grade 8.8 bolts had sheared.

Operations then secretly fitted 10.9's and the bolts failed again. It transpired that Caterpillar track shoe bolts had also failed(??????)

I happened to catch Operations welding the alloy decks to the mild steel'ish sideframe. I made the mistake of asking just what welding rods were being used and was answered that the rod selection was my affair.

Seeing that the welding op was the first thing I knew about the whole business it was Lavabo. This was before proper procurement methods had filtered down into bulk handling affairs; when the Cowboys still had free range. But why have so many Cowboys turned up amongst .....?

Buy proper screens! ■

Originally Posted by louispanjang

I saw an amusing cause of impact damage where the deck fixings were inadequate.

In RAK I was given Turkish made screens as OEM, before I was engaged.

First the sides cracked within 6mm of the chalk line I had drawn while they were still on the delivery truck.

Once installed; the deck plates slid about a bit because the grade 8.8 bolts had sheared.

Operations then secretly fitted 10.9's and the bolts failed again. It transpired that Caterpillar track shoe bolts had also failed(??????)

I happened to catch Operations welding the alloy decks to the mild steel'ish sideframe. I made the mistake of asking just what welding rods were being used and was answered that the rod selection was my affair.

Seeing that the welding op was the first thing I knew about the whole business it was Lavabo. This was before proper procurement methods had filtered down into bulk handling affairs; when the Cowboys still had free range. But why have so many Cowboys turned up amongst .....?

Buy proper screens!

louispanjang

You need to know the limitation of the screen but proper installation/commissioning is often neglected. ■

Originally Posted by sganesh

Dear all,

When I faced a similar situation, I was given the feed backs as follow.

The exciter was recently reconditioned by the supplier by himself and fixed back with the screen. Within 24 hours, the beam developed the crack.

1. No hitting of vibrating body with the stationary structure.

2. No looseness of exciter fixing bolts with the cross beam.

3. No jamming at receiving or discharge chute.

4. All the four counterweight masses were measured. All are having uniform counter weight.

Requesting any additional cause, which can lead to cracking of vibroscreen cross beam , on which this single exiter is fixed.

Thanks & regards to all.

Dear all,

Though we have 26 numbers of same type & same application, beam crack happened in only, one of the vibroscreens. Sorry for not mentioning in the first post itself.

Thanks to all whoever is interested in this thread & Regards to all, ■