Maybe you can give some background information? Like what you are screening and some machine details? Speed, stroke etc.

That will allow forum members to assist you. ■

If the screen is breaking along the support so soon then the failure is probably due to inadequate tension in the mesh.

Sagged material at each side of the support is moving to and fro and rubbing the deformed mesh over the support as well as inducing localised fatigue.

Simple. ■

Dear Mr.Mohandes,

Are you using bucker-up strips? They are made of rubber, inverted "U" shaped strips fixed above the supports. They will avoid direct metal to screen cloth contacts.

They will help to prolong the screen cloths life.

Requesting your reply.

Thanks & regards, ■

Is there any reduction in frequency of damage, after replacing bucker-up strips?

Did you locally develop any parts, say bucker-up strips or the screen cloths? When spares are locally developed, there could be chances that some important parameters missed out. If all are purchased from OEM ( original Equipment Manufacturer ), you need to seek his opinion, other than getting the replacement.

How do you ensure that the screen cloths are properly tightened, prior to putting in service?

Thanks & regards, ■

maybe the screen tension is not good enough. when you run the screen, the mesh hits the support rubber time and time again. so the rubber will damaged in the short time. After that the screen mesh touch the support ribs and still hit it time and time again, so the mesh gona broke in this area. I think this is the main reason. You should check the tension first. ■

first of all:

1. measure exact distance between the sideplates (inside)

2. whatever the total inches are, now subtract 1.5" and that should be the Measurement outside edge to outside edge of the steel edges that are over the wirecloth

3. this ensures, you have 3/4" on each side of the sideplate, to allow for TIGHTENING the wirecloth..to what we call DRUM HEAD TIGHT...like a guitar string

4. if loose, the wirecloth slaps up and down and RIPS along the support rails, rubber lined or NOT

5. IF no rubber on the rails, or worn out, you strike steel of wirecloth on the steel of the support rail and it RIPS QUICKER

6. if wirecloth rips = ABUSE. if wirecloth wears DOWN = you are tensioning properly

7. QUITE often, wirecloth suppliers DO NOT SUPPLY TO wirecloth OUTSIDE EDGE dimensions properly and this results or CAN be the cause of your problem.

8. another TIP, because wirecloth is woven, it loosens at the intersections after one shift of running, so we do recommend you RE-TIGHTEN it after say 8 hours to TAKE that bit of slack out of it and make it very tight.

9. the SUPPORT RAILS it is sitting on...may NOT have enough HEIGHT to them across the width of the box...if too low, the wirecloth CAN NOT BE TIGHTENED, and will break along the support rails.

10. poorly woven wirecloth can break also. if the CRIMPING DYES are WORN OUT...and they do...they can actually crimp the wire and "BLUNT IT OR PUT A UNSEEN HAIRLINE FRACTURE" in the crimp spot before weaving in the LOOM and it will break at those spots quicker, even IF UNDER GOOD TENSION..

11. THE TENSION PLATES that hold the wirecloth in, if MADE WRONG, and they quite often are, MAY BE NICE AND TIGHT BUT, if the lead edge is not engaged into the BENT EDGE OF THE WIRECLOTH HOOK, it will HOLD THE WIRECLOTH up at the side edges and YOU WILL NEVER GET IT TIGHT.

12. LOTS of people make their own and make them wrong when they copy the OEM ORIGINALS.

GOOD LUCK..

GEORGE BAKER - MODERATOR ■

one more comment on TENSIONING WIRECLOTH:

1. if you can imagine, trying to STRETCH OR TENSION or TIGHTEN wirecloth with 2 guys each pulling on the METAL SIDE HOOKS as hard as they can ON A FLAT SURFACE...they could pull til they TURN BLUE and would obtain ZERO or NO TENSION.

2. NOW, take that FLAT SURFACE and say cut a 45 gallon drum (in half) and now have the same 2 guys yanking DOWNWARD on those same edges and you would in fact ...what we call...."Break the back of the wireclcoth" and STRETCH it over the CAMBER OR ARCH of the 45 gallon drum's arch and it would TIGHTEN UP VERY TIGHT.

3. SO....sometime...the height of the STEEL SUPPORT RAILS on which we mount the RAIL RUBBERS ON is or may NOT be high enough in the centre arching to the sides.

4. last but not least, DID YOU KNOW...the finer the wirecloth is....the closer the steel support rails should be...as finer cloth is flimsier and needs more support rails to HOLD IT UP or it can SAG AND RIP.

5. TOP deck support rail spacing can be wider, because the WIRE DIAMETERS ARE BIGGER AND do not need to be spaced as tightly.

To take the TENSION out of your situation, follow those simple rules of thumb above. IT WORKS.

GEORGE BAKER - Moderator ■

I agree with the others who claim the problem here had to be the lack of tension in the woven wire mesh that you were using. You can pull on the mesh all that you want in order to try to change the tension, but the bottom line is that if you are using low quality mesh, the tension will never be what you expect.

Read up on the manufacturers sites, such as the "resources" tab here

They have a lot more information than the average joe about the product that they are manufacturing. I would even give them a call and see what the say the problem with the tension is. Where was this material purchased? I would go right back to the source and ask for some replacements. ■

sometimes:

1. the vibrating machine, has the support rails for the wirecloth....too widely spaced...for fine mesh wirecloth.

2. The finer the wiremesh, the closer the support rails should in fact be....to avoid sagging between them and eventually ripping.

3. sometimes for fine mesh wirecloth...wirecloth manufacturers actually make a special "sandwich section" which is 2 pieces of wirecloth inside one HOOKED EDGE. a 1/4" clear opg beneath a 2mm opg to give it support....to avoid DAMAGING the finer mesh from sagging between the rails.

But, honestly.....i would really double check the "OUTSIDE EDGE, HOOK DIMENSIONS" if they are too wide, you will never, ever be able to TIGHTEN THE WIRECLOTH OR TENSION IT. The steel hooked edges will in fact bottom out or CONTACT the sideplates when you try to tighten them more....if this is the case ...the wirecloth is being ordered TOO WIDE. (TAKE THE measured distance between the sideplates....total inches...and subtract 1 1/2 inches...and that will make the outside hook dimension to order) IE: 48" INSIDE THE sidewalls or sideplates MINUS 1.5" = 46.5" oh ...then you will have proper takeup space to TIGHTEN.

ps: more tight is better than less tight....after 8 hrs tighten all bolts, 1/4" turn more or UNTIL TIGHT...as woven wirecloth begins to loosen after 8 hrs....

LASTLY....DO NOT EVER...screw down...this will be a disaster...it will NOT WORK, must be tightened. ■

No formal rule – but for say 0.5 to 2.0mm dia wire, I would suggest supports at 200 to 250mm centres. ■

Forgot to say - with the above wire mesh on a 1600 wide screen – suggest the support frame should be double camber. ■

Forgot to say - with the above wire mesh on 1600 wide screen – the support deck should be double camber. ■