Dear kamlesh

EP Refers to Type of carcass Ep conveyor belts consists of fabric utilysing a polyster fibre for warp and polymid fibre for weft.

Ep belts have less stretch than Nylon - nylon belt

PIW ---- refers to belt tensile strength pounds per inch belt width

EP -1250 means CAcass type EP having tensile strenth of belt 1250 kn/m

A R SINGH ■

Kamlesh

This might help you. Look on pages 4 & 5.

http://www.conveyorbelt.com/news/new...RBELTNEWS.pdf

Gary ■

Dear Shri Kamlesh,

In case of EP belts, the carcass designated figure as per European practice indicates the “breaking” strength of carcass. This means, EP 800/4 belt has 4 number of plies and carcass breaking strength is 800 N/mm (kgf/cm) for total of all plies together. As per modern practice the allowable breaking strength is fixed by the designer on the basis of safety factor applicable to the specific case (which he is to choose). The allowable strength is to be derived for the weakest zone i.e. at the vulcanised joint. For average condition, the universal safety factor is 8. For the aforesaid belt, the working (allowable) strength would be 800 x 0.75 / 8 = 75 N/mm. This considered loss of one ply at the joint and hence the factor 0.75 i.e. 3/4.

The CEMA book page no. 193 states that PIW rating is used for reduced ply belting and the mentioned PIW figure implies “allowable” belt rating for complete carcass as pound per inch width. Forum readers from USA can give more explanation or correct my statement, if need be.

The American practice considers some safety factor as a part of the carcass aforesaid notation figure but the value of this safety factor is not clarified in the said book.

As you will observe, the method / level of notation are different in both the methods. European method indicates carcass by its breaking strength and safety factor varies case to case basis. It seems American carcass notation indicates allowable (working) strength.

I think now you will be able to make comparison and derive the conversion factor.

In case of multiply EP belts (usual belts), the CEMA book also states that they have practice of specifying belt carcass as 4 plies MP 35 which means it has allowable carcass strength of 4 x 35 pound/inch in context of vulcanised joint.

If you are referring to a contractual matter, best option would be to write to your American supplier and obtain the breaking strength and the safety factor which is applicable for the data furnished by him. For exact comparison, you have to bring both the data at common level.

I think this query and the response by various readers will be beneficial to the readers by large for the belt notation practices.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■