Have they bought this thing yet? If they have my sympathies.

You should save a lot of effort and breakdowns by using a chain plough conveyor and eliminate 99% of your problems and required equipment.

Google
here in the US they build coveyors for this /wood chips etc. and manure handling this conveyor size would be easy to install in one easy setup with out a take up or any other problems and it would not screw up because of moisture!, you would be really surprised to see how much material a paddle/plough conveyor will move with a very small motor and a reduction gear box and there are no heads pulleys, tail pulleys, conveyor belt, conveyor belt splices and maintenance is a breeze.

Also the installation time is much less as it all

goes in in one piece with out any extra work with fewer problems and easy set up.

Also the initial expense and time required for installation will be much less as you have less equipment to install and maintain.

It-this makes me wonder why they are not using chain/paddle conveyors anyway to move wood products as is done here in the US? Do your bosses even know about them?

Its always better to show a better way to get things done if you know it.■

I hate to see your perfectly good ice cold "Tiger" or "Lonestar" beer in a warm lagoon but:

Depending on your supplier and their reliability you are at the mercy of the retailer and I can not give you any better advice as they will not tell you anything except push this button to start it and this button to stop it.

Depending on the quality of the finished products components this will determine everything.

So you must look at CEMA standards for construction of components as most manufacturers follow them to guarantee quality.

I can not comprehend why they are unwilling to use in stock components for the job as they already have the parts for their other conveyors.

I do not envy thee as you may end up bearing the brunt of this since they seem to be washing thier hands of this matter. ■

I have not done belt selection for ages but can offer some generic comments.

Belts - pls look up Goodyear or Dunlop belts. U need to select belts for the following - load support, trough ability, tension rating and wear.

Woodchips has low density - do support will not be an issue.

I can not comment on the belt mentioned - seems OK at a glance.

I know that U can also get the belt edges moulded to help minimise moisture ingress into the fabric plies.

Your trough angle is only 20 deg...normal angles are 30-35deg.

Stay with same sized drums - less hassle. The drum diameter is a function of the belt tension and plies etc - refer belt suppliers data - as above.

Idlers could be at 1500mm spacing. The idler selection is a process of designing for...

belt sag - greater spacing means more sag and this can mean spillage > can be reduced by increasing the belt tension by increasing the GTU weight > this then could influnce the belt specifications.

bearing life in the idler rolls

Considering the low density of the product - U would be looking at low rating idlers eg 102 or 114mm diameter. Please refer Catalogues from Sandvik, Tyton etc etc.

The belt line from the top of the centre roll to the top of the pulleys can be either - even/level (as suggested by your contractor) or at a height above (as U suggest). The formers means more distance for your transition due to the greater height change. Hence, people tend to go for the later - refer text from Belt suppliers etc... But - pls note that with light belts/loads..U may get belt lift up under starting with intermedtiate transition arrangements > the belt may lift up into the feed end skirts etc. I think that U may be better off as suggested by your contractor. Pls also consider the roll off effect of the load as the belt flattens out..esp with slow belts...can get material rolling off the edges...

U do not state what type of arrangement U have with your contractor eg design and construct, performance based or around some basic client requirements. Sounds like the contractor has some design responsibilities to me - so U need to be careful that the details of the responsibilities do not get clouded.

U can find CEMA on the web - Conveyor Equipment Manufacturers Association - USA.

Cheers

James ■

For your answers:

Contact bulk asia for a CEMA handbook or a good book seller in Hong Kong or Shanghai or CEMA itself.

The heavier the belt,the heavier the weaving of fabric sandwich construction from the rubber manufacturer, the better the construction, a thick hide on the carrying side will improve belt life overall.

As far as splices go its up to your maintenance

department, hot vulcanising is best and the most costly but least costly over the life of the belt.

Flexco fasteners are very good but if it is not done right ther first time it will ruin the belt.

Idler spacing: it all depends on the weight of the material being moved. Typically a 24-36 belt has a five foot spacing for troughing idlers and 10 foot for the return idlers which are typically centered in the belt stand legs.

You will also need good bearings for the head drive and tail pulleys a "Timken" bearing catalog will verify the bearing selection for belt speed.

Double tapered barrel rollers or double barrel rollers are specified as a rule.

You have a slow belt speed so there is not much to worry about there except to make that if a traditional splice is used to cut a dutchman on the edges to make sure there is no stress on the belt as it transits the tail drive and head pulleys-a dutchman is a small pie slice wedge cut from the edge of the belt to allow easier movement over the head, drive and tail pulleys, it also reduces the potential for edge damage.

Troughing and return rollers are anywhere from three to five inches or more in diameter-the larger the roller diameter the slower the speed of the roller-it matters not the size but the greasing of the rollers.

The wood chips will probably weigh less than the conveyor belting per foot so idler spacing should not be an issue-rmember you are carrying the belt from point A to point B.

The head pulley is always flat at the discharge end and higher than the tail pulley at the tranfer point so the material is thrown off the head pulley and dropped a verticsl distnce to the tail pulley center and then taken away by the receiving belt.

You should also consider lagging the head and drive pulleys.

Make sure the tail pulley has replaceable skirting-a split top frame that folds out to ease replacement of the skirting.

With the head pulley you will always have a slight distance from the last troughing idler to the head pulley and the trough of the belt will carryy to the head pulley and flatten out while discharging.

Hopefully your questions are answered this time. ■

OK is it safe to assume you are nowhere near Kuala Lumpur and a good book store over there?

Other wise I would order a copy from CEMA and have them send it to you via united parcel service, DHL or Federal Express as they all fly most of thier cargo in your part of the world.

for Bulk Asia 2005

technicom@vsl.com

Ask them how to get in contact with someone who sells the CEMA handbook locally.

Technicom Management Services

132 Wheeler Road, Cox Town

Bangalore 560005

India

If all else fails spend time at the CEMA web sitew ■

Mr. Young & Silly,

Reading through all of the comments so far I want to offer the following:

1.) Compared to the drag conveyor, the belt conveyor is a much better choice. Properly designed the belt conveyor will have lower initial cost, much lower lower operating and maintenance costs (less wear and tear). The belt conveyor will require less power and will consume less energy (much less travel resistance on rolls with bearings compared to dragging over a bed). The belt conveyor will be more reliable.

2.) Mr. Morrish did a good job of describing the belt selection, idler spacing, pulley diameter. Any conveyor belting catalogue publishes the relavent values; load support, troughability, cover selection guidance, pulley diameters, etc. and these catalogues are available free of charge from the vendors.

3.) You are correct on the pulley height at transitions. Indeed if you line up the pulley surface with the neutral axis (center of gravity of the carcass) then there is no net uplift nor downward pressure since you will not deflect the neutral axis belt line. There is a long discussion on this matter in another thread (of this forum) entitled "CEMA Error; Trough Belt to Pulley Transitions".

4.) Most standards list safety and the public welfare as an important part of their mission, so it amazes me when they restrict access to these standards by putting such high prices for their purchase. On the other hand it would be reasonable to expect that your company would want to keep a library with the governing standards, availble for borrowing by their technical people.

Joe Dos Santos ■