COVER RUBBER GRADE FOR GENERAL PURPOSE BELT
RMA - Rubber Manufacturers Association
There are no standards for heavy-duty conveyor belts in the US.
Only a few cover grades are determined by the US Rubber Manufacturer's Association (RMA), which are widely being used.
Officially, the RMA recommendations were replaced by ARPM (Association for Rubber Product Manufacturers) specifications in .
GRADE I (RMA I)
Superior resistance to abrasion, cutting, gouging, and tearing caused by the impact of large material. Recommended for transporting large, heavy, lump
ores, quartz, trap rock, granite, glass bullet, scrap, ballast and similar heavy duty applications.
You can find more information on our web, so please take a look.
GRADE II (RMA 2)
Excellent for continuous abrasion. Good resistance to cutting and gouging.
Recommended for conveying sand gravel, limestone, crushed rock, slag, coke,
coal, cement rock, potash, trona, salt and other abrasives.
For more information, please visit haichuan.
APLICATION
Suitable for wide ranges of operating conditions. The bulk handling conveyor belt is widely utilized in the industrial fields of mining, engineering works,
cement, quarry and aggregate industries. Depending on the cover rubber selection, the belts are suitable for both conveyor and elevator services.
SUPER ABRASION RESISTANT (SAR)
Designed for applications requiring superior resistance to abrasion.
SUPER OIL RESISTANT (SOR)
Highly resistant to mineral oil and most other oil that cause swelling and sponginess.
Recommended for handling animal or vegetable fats, oily metal, etc.
MODERATE OIL RESISTANT (MOR)
Recommended for specialized service such as waste disposal sewage, sludge, and oil treated materials. This compound is not recommended for high impact
handling.
SUPER HEAT RESISTANT (EPDM)
For severe temperature from 194°C to 222°C. Designed for foundry sand, carbon black, ashes, salt, coke, cinders casting and slag.
FIRE RESISTANT (MSHA)
Meet U.S.A. Mine Safety and Health/Administration requirements. Designed for service in coal, potash, salt and other underground mining where fire
resistant belts are mandatory.
OIL & FIRE RESISTANT (MSHA-MOR)
Meet U.S.A. Mine Safety and Health/Administration requirements. Recommended in service where fire and oil resistant belts are required.
STATIC CONDUCTIVE OIL & FIRE RESISTANT (MSHA-MOR-SC)
Specially compounded for the oily effect of grains. This is static conductive and flame resistant; meets MSHA requirements.
CARCASS STYLE
Carcass is identified according to reinforcement fiber type:
E indicates polyester.
P indicates nylon.
E E designates a belt with polyester warp and weft.
P P indicates a nylon warp and weft.
E P is a carcass with polyester warp and nylon weft.
PIW and N/mm
PIW means pounds per inch of belt width and is widely used in the United States of America. The PIW figure is indicating the working tension a
conveyor belt is intended to be used for, irrespective of the breaking strength of the splice. Usually, the belt's breaking strength is not given.
Outside of the USA, the breaking strength of the conveyor belt is used, rated in N/mm, i.e. Newton per millimeter of belt width. The belt breaking
strength is determined precisely, depending on the operating conditions, the splice type etc. The safety factor is related to the weakest point of the
conveyor belt, which is the splice.
Without consideration of a safety factor, PIW are converted into N/mm by multiplying by 0.175.
Example: PIW x 0.175 = 400 N/mm.
N/mm converted into PIW is multiplied by 5.71. Example: 400 N/mm x 5.71 = PIW.
If a safety factor of 10 is assumed for both terms, then a 400 PIW belt would equal to a 700 N/mm belt. However, this is not academic.
The above applies to textile conveyor belts. For steel cable conveyor belts, the rating in N/mm breaking strength is used in the USA, too.
Tensile Strength and Elongation at Failure
Let's now define &#;tensile stress&#; in tensile. When we subject a given material to an increasing tensile force, the material progressively increases in length
and increases the smaller its modulus of elasticity. At some point the material departs; The force corresponding to this moment is called the breaking
force. If we divide this force by the area of the section subjected to traction (initial section), we obtain the so-called &#;breaking tension&#;.
On the other hand, at the moment the material broke, it had a certain maximum deformation or maximum elongation, as preferred. This maximum
deformation is called "fracture deformation" or, more commonly, "elongation at failure".
Let us now see the current units in which these properties are expressed.
The modulus of elasticity is expressed in units of tension, it´s one force per unit area.
For example:
kg force / cm2
Newtons / mm2
MPa = 106 Pascal
Conversion: 1 MPa = 10.197 kgf / cm2 = 1 N / mm2
As we have seen, in the case of rubber, due to the non-proportionality between tension and deformations, the modulus value must always be accompanied
by the corresponding elongation value.
The breaking tension is expressed in the same units as above.
Elongation at break is expressed as a percentage of the initial length, for example 550%, which means that the initial length increased by 5.5 times.
In rubber, the characteristics &#;Modulus x%&#;, &#;Tensile strength&#; and &#;Elongation at fracture&#; are very important properties that determine, to some extent,
their field of application - beyond, of course, many other characteristics.
Having defined these properties and the units in which they are expressed, let's look at how they are determined in practice.
DIN - GERMAN INSTITUTE FOR STANDARDIZATION
EPM AND EPDM RUBBER
EPM (ethylene-propylene) is a saturated rubber made by copolymerization of ethylene and propylene. Owing to the lack of double bonds, this kind
of rubber cannot have cross-links with sulphur or chemicals that release sulphur, but only with organic peroxides.
As to EPDM (ethylene-propylene-diene), it was developed because the peroxidic cross-linking adopted in saturated ethylene-propylene rubber
(EPM) has some drawbacks as well. EPDM has additonal double lateral bonds created by a reaction with a &#;diene&#;; this makes cross-linking with sulphur
and accelerants possible.
Properties
- The properties of vulcanized products depend above all upon the kind of rubber used, nevertheless they are on the whole quite similar.
- As a rule cured EPDM products show good resistance to high and low temperatures, ageing and chemicals, good elasticity and good insulation properties
- Impact strength: 40 to 60%
- Extensibility: 150 to 500%
- Heat resistance:
- EPM with peroxidic cross-linking provides better heat resistance (up to about 150°C)
- Cured peroxidic EPDM products with suitable composition can withstand water and steam up to 200°C. for a long time without being severely
affected..
- Resistance to low temperatures: up to about -50°C.
- Gas permeability: quite high, not recommended when this is an issue.
- Resistance to chemicals:
- Very high thanks to its polymeric chain.
- Vulcanized EPDM rubber products can withstand::
Water and hot steam to +130°C, also up to peaks of 200°C.
Glycol-based brake fluids
Leaching fluids containing sodium and potassium carbonate (detergents and many organic-inorganic bases)
Saline solutions and oxidizing agents.
Hydraulic fluids containing water and glycols
Hydraulic fluids containing phosphoric acid esthers
Silcione-based oil and grease
Many polar solvents such as alcohols, ketones and esthers; Skydrol 500 and
Vulcanized EPM and EPDM products are not recommended for use with hydrocarbons in general.
Applications
- The automobile industry is currently the largest consumer of EPDM, employed for instance in spongy rubber gaskets for car doors and boots, seals
for windows and headlights, bumpers, hose and gaskets in general.
- Joints, hose and gaskets for household appliances (washing machines and dishwashers): EPDM is widely used because of its resistance to
detergent liquids and solutions and to high temperatures.
- In electric cables EPDM is also frequently used because of its good electrical properties (combined with a good resistance to weathering and limited
water absorption).
251:
Conveyor belts with textile carcass - Widths and lengths
252:
Conveyor belts - Ply adhesion between constitutive elements - Test method and requirements
282:
Conveyor belts - Sampling
283:
Textile conveyor belts - Full thickness tensile strength and elongation - Specifications and method of test
283-1:
Textile conveyor belts - Determination of tensile strength, elongation at break and elongation at the reference load
284:
Conveyor belts - Electrical conductivity - Specification and test method
340:
Conveyor belts - Flame retardation - Laboratory scale flammability - Specifications and test method
432:
Ply type conveyor belts - Characteristics of construction
433:
Conveyor belts - Marking
505:
Conveyor belts - Method for the determination of the tear propagation resistance of textile conveyor belts
583:
Textile conveyor belts - Tolerances on total thickness and thickness of covers - Test methods
583-1:
Conveyor belts with a textile carcass - Total thickness and thickness of elements - Methods of test
703:
Conveyor belts - Transverse flexibility and troughability - Test method
:
Steel cord conveyor belts - Cord-to-coating bond test
:
Conveyor belts - Determination of strength of mechanical fastenings - Static test method
:
Rubber - Resistance to ozone cracking
:
Conveyor belts - Drum friction test
:
Continuous handling equipment - Nomenclature
:
Rubber products - Guideline for storage
:
Conveyor belts - Determination of minimum pulley
:
Conveyor belts (fabric carcass) - Adjustment of take-up device
:
Conveyor belts - Heat resistance - Requirements and test method
:
Determination of abrasion resistance
-1:
Rubber, vulcanized or thermoplastic - Preparation of samples and test pieces - Physical tests
:
Belt conveyors; calculation of operating power and tensile forces
:
Conveyor belts - List of equivalent terms
:
Conveyor belts - Guide to storage and handling
:
Conveyor belts - Formula for transition distance on three equal length idler rolls
:
Fire tests - Reaction to fire - Smoke generated by building products (dual-chamber test)
:
Steel cord conveyor belts - Methods for the determination of total thickness and cover
-1:
Steel cord conveyor belts - Longitudinal traction test - Part 1: Measurement of elongation
-
Steel cord conveyor belts - Longitudinal traction test - Part 2: Measurement of tensile strength
:
Steel cord conveyor belts - Cord-to-coating bond test - Initial test and after thermal treatment
:
Steel cord conveyor belts - Adhesion strength test of the cover to the core layer
:
Conveyor belts - Determination of elastic and permanent elongation and calculation of elastic modulus
:
Conveyor belts - Characteristics of covers - Classification
:
Conveyor belts - Formula for transition distance on three equal length idler rollers (new method)
-1:
Conveyor belts - Propane burner test
-2:
Conveyor belts - Large scale flammability test
:
Conveyor belts for general use - Electrical and fire safety requirements
:
Steel cord conveyor belts - Determination of horizontal and vertical position of the steel cords.
:
Conveyor belts - Specification for conveyor belts of textile construction for general use
:
Conveyor belts for underground use - Electrical and fire safety requirements
:
Steel cord conveyor belts (type A) and woven steel cord or steel strand conveyor belts (types B and C)
:
Steel cord conveyor belts - Vulcanized splices
-1:
Steel cord conveyor belts for general use - Design, dimensions and mechanical requirements
-2:
Steel cord conveyor belts - Preferred types
-3:
Steel cord conveyor belts; special requirements for underground use
-4:
Steel cord conveyor belt - Vulcanized splices
:
Textile conveyor belts - Determination of the endless length
:
Conveyor belts - Test atmospheres and conditioning
:
Textile conveyor belts for underground mining
DIN (GERMANY)
252
Ply separation strength
284
Electrical conductivity; specifications and test method
340
Laboratory scale flammability characteristics; requirement and test method. Rev. Oct .
505
Method for the determination of the tear propagation resistance of textile conveyor belts
583
Textile conveyor belts; total thickness and thickness of constructional elements
703
Troughability
Determination of strength of mechanical fastenings; static test method. Issue .
Drum friction test
Steel wire ropes - characteristics
Rubber products; requirements for storage, cleaning and maintenance
Determination of elastic and permanent elongation and calculation of elastic modulus
Steel wire ropes
-1
Fire simulation flammability testing; propane burner test
-2
Fire simulation flammability testing; large scale fire test
Conveyor belts for general use; electrical and flammability safety requirements.
Steel cord conveyor belts; determination of displacement of steel cords
Specification for rubber or plastics covered conveyor belts of textile construction for general use
Conveyor belts for underground use; electrical and fire safety requirements.
-3
Steel cord conveyor belts; special safety requirements for underground use
Textile conveyor belts; determination of endless length
Flammability of conveyor belts; specifications and method of test
-1
Synthetic materials for underground use; hygiene requirements
Basics for the design of belt conveyors (new version of Dec. superseding the and issues)
Textile carcass conveyor belts
Fire resistant conveyor belts for coal mining
Antistatic conveyor belts; requirements and testing
Continuous mechanical handling equipment; idler sets for belt conveyors, principal dimensions
Textile carcass conveyor belts for underground coal mines (&#;self-extinguishing&#; grades) Issue
Dynamic testing of conveyor belt joints
Belt conveyors for underground coal mining
Conveyor belts for coal mining; determination of the limiting oxygen index (LOI)
Textile carcass conveyor belts for use in underground coal mines; fire testing
Scraper rubber for underground coal mining
Textile carcass conveyor belts for coal mining; permanent joints
Indentation rolling resistance of conveyor belts - Requirements, testing
Steel cord conveyor belts for underground coal mining
Steel cord conveyor belts
Textile conveyor belts for underground use
Indentation rolling resistance of conveyor belts
Steel cord conveyor belts; adhesion strength test of core to cover layer
Testing of breaking strength and elongation of rubber
Testing of hardness of rubber (Shore A and D)
Testing of tear strength of rubber
Determination of the visco-elastic properties of rubber
Testing of abrasion resistance of rubber
AS (AUSTRALIA)
-
Textile conveyor belts
-
Steel-cord conveyor belts
-.
Testing of conveyor belts
.1-
Testing of conveyor belts - Determination of length
.2-
Testing of conveyor belts - Determination of thickness
.3-
Testing of conveyor belts - Determination of tensile strength and elongation
.4-
Testing of conveyor belts - Determination of troughability
.7-
Testing of conveyor belts - Determination of ply adhesion
.8-
Testing of conveyor belts - Determination of resistance to tear
.9-
Testing of conveyor belts - Determination of electrical resistance
.10-
Testing of conveyor belts - Determination of ignitability and flame propagation
.11-
Testing of conveyor belts - Determination of ignitability and surface temperature subjected to friction
.12-
Testing of conveyor belts - Determination of combustion propagation
-
Guide to splicing steel cord conveyor belts
-
Glossary of terms
.
Conveyors - General safety standard
.
Belt conveyors for bulk material handling
.1-
Determination of strength of mechanical fasteners
-
Fire resistant and antistatic requirements for underground belting
(under development)
Conveyor belt indentation rolling resistance
CHINA
GB/T -
Textile conveyor belts for general use
GB/T -
Steel cord conveyor belts for general use
GB/T -
Flame resistant textile conveyor belts for general use
HG/T -
Oil resistant conveyor belt
GB/T -
Heat resistant conveyor belts
MT 668-
Steel cord fire resistant conveyor belting for underground coal mining
MT830-
Textile reinforced fire resistant conveyor belts for underground coal mining
USA
There are no standards for heavy-duty conveyor belts in the US.
Only a few cover grades are determined by the US Rubber Manufacturer's Association (RMA), which are widely being used.
Officially, the RMA recommendations were replaced by ARPM (Association for Rubber Product Manufacturers) specifications in .
If you are looking for more details, kindly visit Mt668 Flame Retardant Conveyor Belt.