Temo,

You certainly have a problem. In the long term - replace the screen with a bigger and stronger model.

In the short term -

1 - reduce capacity during wet

2 - bypass ore to a drying area

3 - try to wash out the dirt before it gets to the screen

4 - weld stronger side plates - these are cracking due to metal fatigue from overload

5 - wash the screen

6 - stop the screen, wash off the dirt, and restart ■

An interesting case as usual:

1. Rubber buffers (terminology) is this a TYLER TYROCK by chance? They do not have coil springs on this particular model but RUBBER in shear MOUNTS about 8 per side.

2. By your description, you are only failing support rubbers at the FEED END or overloaded end, if I understood correctly.

ADD another set of support rubbers to FEED END only is one possibility.

3. It you lose your RUBBER spring supports.....this allows the screenbox to SIT LOWER DOWN and strike or contact the structure on shutdown and this SHOCK action WILL Cause Mr. Sideplate to CRACK......for sure.

4. 15 degrees for scalping is not bad by the rules.....but, a little raise by 2-3 degrees would really help due to non free flowing aspect of some of the feed.

5. URETHANE has LOW PERCENTAGE of open area ......even when they put the margins right over the support rails. LOW OPEN AREA equals less TPH and especially less TPH when non free flowing. YOU must have an ABRASION problem with your feed material.........is this true? Otherwise you are sacrificing OPEN AREA and TONNAGE CAPACITY for no particular reason.

6. Out of the box suggestion: I had this problem in Quebec Canada limestone quarry. I put in a new 4 bearing screen to feed a primary IMPACTOR. the client decided to set it into place at eleven degrees angle....lower than the 15 degrees recommended and sold for. They BURIED the screen, SPLIT THE RUBBERS in shear mounts out, killed their capacity....vs the old machine that I retrofit replaced and were unhappy campers.

Dumping into this with 35 TON mining trucks. This heavy duty screen was scalping prior to the impactor. Actually, it was probably more suited for a nice HEAVY duty brute force VIBRATING grizzly feeder.

We had to make this work......they would not move off 11 degrees..too much extra cost at that point. Sooooooooo....we installed AIRBAG mounts around the vibrating body....so when the massive dump loads HUMPED onto it...the rubber buffers or shear mounts WOULD NOT BOTTOM out under the strain and rip and fail.....the airbags (kinda like you see on transport truck trailers) coushin the IMPACT or weight and stop the bottom edge of the sideplates of the vibrating box from striking the structure.

This also stopped the SHAFT from being shock loaded, a very expensive thing to replace.

BLANKED out plate on this machine. .....It sounds like you have some large BLANK plate areas at the FEED END and maybe the discharge end? These will contribute to problems....please give me a bit more detail here.

It's been a Shear pleasure ....... ■

MORE INFORMATION to ponder:

I did a long reply here but, somehow deleted it.........so

I did a thorough VSMA calculation and the screen is undersize for a few reasons:

TOP deck opg is nominal 3" will pass 6.17 tons per sq ft with wirecloth with about 74% open area per VSMA

2ND deck opg is nominal 1 3/4" will pass 4.51 ton per sq ft with wirecloth with about 68% open area per VSMA

.........

AVERAGE open area on both decks = 71% using WIRECLOTH

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

Using URETHANE open area average might be 30%

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

We just LOST 40% thrus availability using URETHANE.

I assume you have a need for urethane due to some HIGH ABRASION factor - if not we are causing tonnage problems and others ....overload, trouble passing, carry extra weight, bearing life reduction to name a few

........

DECK SIZE: 2440 X 6800MM (8.1 X 22.6 feet)or 183.06 sqft avail.

Subtract: blank outs (8.1 x 18.3 feet) or 148.23 sq feet available

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

Average tons passing both decks 6.17 + 4.51 = 10.68 divide by 2 = 5.34 tons per sq foot x 148.32 = 792.03 total tons WIRECLOTH

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

LESS 40% using URETHANE = 475.21 total tons using Urethane

These are round values but, practical representation

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

WHAT manufacture is this unit please?

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

Another little interesting tidbit is......if you speak to the urethane suppliers......most will want the screen to operate a bit high G FORCE than typical 3.5 to 3.8 range......and want it more like 4.0 G's to really activate the urethane otherwise the screen is a bit SLUGGISH....as POLY is more heavy per sq ft than wirecloth....so the static wgt to vibrate increases.

The otherside of the coin........if you are running at 4.5 G's on a big heavy overloaded screen......this typically is over the recommended G factor designers design for. They like to screen but, at the end of the day STILL HAVE NO CRACKS in the machine. If you are running constantly IN that high range.....the machine will crack in my opinion.

Is the POLY.....hooked side tension sections or 2 x 4 squares or?

"Urethane can be a slippery slope sometimes" but, very well proven in thousands of applications worldwide.

Shaking it up. ■

When I covered the GOLD MINES up north....the engineering firms became very good at taking a CIP slurry screen at say 4x10 and jumping it up to a 5x12 strictly as a safety factor for the reduction in OPEN AREA on urethane vs normal stainless steel wirecloth.

It works. ■