TEST METHODS
Below are the list of the tests against various standards.
ASTM International
ASTM D 378 Standard Test Methods for Rubber Elastomeric Belting, Flat Type Included are tests for:
Measurements of Dimensions
Physical Properties of Elastomeric Covers Immersion Tests
Adhesion Tests
Breaking Strength and Modulus Testing Flame Test for Belting
Carcass Tear Test Troughability Test
Breaking Strength of Mechanical Fastenings (Static Test Method) Elevator Belt Bolt Holding Strength Test
ASTM D 2228 Standard Test Method for Rubber Property - Relative Abrasion by Pico Abrader Method ASTM International standards can be obtained at www.astm.org.
Canadian Standards Association
CAN/CSA-M422-M87 -- Fire Performance and Antistatic Requirements for Conveyor Belting CSA standards can be obtained at www.csa.ca.
International Organization for Standardization (ISO)
ISO 251 Conveyor belts with textile carcass -- Widths and lengths
ISO 252 Conveyor belts -- Adhesion between constitutive elements -- Test methods ISO 282 Conveyor belts -- Sampling
ISO 283 Textile conveyor belts -- Full thickness tensile strength, elongation at break and elongation at the reference load -- Test method
ISO 284 Conveyor belts -- Electrical conductivity -- Specifi cation and test method
ISO 340 Conveyor belts -- Laboratory scale fl ammability characteristics -- Requirements and test method ISO 433 Conveyor belts -- Marking
ISO 433 Conveyor belts -- Marking (Amd 1)
ISO 505 Conveyor belts -- Method for the determination of the tear propagation resistance of textile conveyor belts ISO 583 Conveyor belts with a textile carcass -- Total belt thickness and thickness of constitutive elements -- Test methods ISO 703 Conveyor belts -- Transverse fl exibility (troughability) -- Test method
ISO 1120 Conveyor belts -- Determination of strength of mechanical fastenings -- Static test method
ISO 1537 Continuous mechanical handling equipment for loose bulk materials -- Troughed belt conveyors (other than portable conveyors) -- Idlers
ISO 3684 Conveyor belts -- Determination of minimum pulley diameters
ISO 3870 Conveyor belts (fabric carcass), with length between pulley centres up to 300 m, for loose bulk materials -- Adjustment of take-up device
ISO 4195 Conveyor belts with heat-resistant rubber covers -- Heat resistance of covers -- Requirements and test methods ISO 4195 Conveyor belts with heat-resistant rubber covers -- Heat resistance of covers -- Requirements and test methods (Cor
1)
ISO 5284 Conveyor belts -- List of equivalent terms ISO 5284 Conveyor belts -- List of equivalent terms (Cor 1) ISO 5285 Conveyor belts -- Guidelines for storage and handling
ISO 5293 Conveyor belts -- Determination of minimum transition distance on three idler rollers ISO 5293 Conveyor belts -- Determination of minimum transition distance on three idler rollers (Cor 1)
ISO 9856 Conveyor belts -- Determination of elastic and permanent elongation and calculation of elastic modulus ISO 10247 Conveyor belts -- Characteristics of covers -- Classifi cation
ISO 10247 Conveyor belts -- Characteristics of covers -- Classifi cation (Amd 1)
ISO/TR 10357 Conveyor belts -- Formula for transition distance on three equal length idler rollers (new method)
ISO 14890 Conveyor belts -- Specifi cation for rubber or plastics covered conveyor belts of textile construction for general use ISO 14890 Conveyor belts -- Specifi cation for rubber or plastics covered conveyor belts of textile construction for general use
(Cor 1)
ISO 15147 Light conveyor belts -- Tolerances on widths and lengths of cut light conveyor belts
ISO 16851 Textile conveyor belts -- Determination of the net length of an endless (spliced) conveyor belt ISO 18573 Conveyor belts -- Test atmospheres and conditioning periods
ISO 21178 Light conveyor belts -- Determination of electrical resistances
ISO 21179 Light conveyor belts -- Determination of the electrostatic fi eld generated by a running light conveyor belt ISO 21180 Light conveyor belts -- Determination of the maximum tensile strength
ISO 21181 Light conveyor belts -- Determination of the relaxed elastic modulus ISO 21182 Light conveyor belts -- Determination of the coeffi cient of friction ISO 21183-1 Light conveyor belts -- Part 1: Principal characteristics and applications ISO 21183-2 Light conveyor belts -- Part 2: List of equivalent terms
ISO 22721 Conveyor belts -- Specifi cation for rubber- or plastics-covered conveyor belts of textile construction for underground mining
ISO Standards can be obtained at www.ansi.org.
German DIN Specifi cations
Many DIN specifi cations are used internationally and most are available in English.
22101 Continuous conveyors - Belt conveyors for loose bulk materials - Basis for calculation and dimensioning 22102-1 Conveyor belts with textile plies for bulk goods; dimensions, specifi cations, marking
22102-2 Conveyor belts with textile plies for bulk goods; testing
22102-3 Conveyor belts with textile plies for bulk goods; permanent joints
22109-1 Conveyor belts with textile plies for coal mining - Part 1: Mono-ply belts for underground applications; dimensions, requirements
1/2 “ D
1 1/16 “ D
4 1/2 “
22109-2 Conveyor belts with textile plies for coal mining - Part 2: Rubber - belts with two plies underground applications; dimensions, requirements
22109-4 Conveyor belts with textile plies for coal mining - Part 4: Rubber - belts with two plies for above applications; dimensions, requirements
22109-5 Conveyor belts with textile plies for coal mining; branding 22109-6 Conveyor belts with textile plies for coal mining - Part 6: Testing 22118 Conveyor belts with textile plies for use in coal mining; fi re testing
22121 Conveyor belts with textile plies for coal mining - Permanent joints for belts with one or two plies; dimensions, requirements, marking
DIN standards can be obtained at www.din.ne, or through ANSI at www.ansi.org.
BOW OF CONVEYOR BELTS
Bow is the concave deviation of the edge of the belt from a straight line between two points along the belt edge. (Camber is the convex phenomenon, on the other edge of the belt.)
Bow is measured by unrolling at least 50 ft (15 m) and more preferably 100 ft (30 m) of the belting from a shaft-supported roll onto a fl at surface, so there is no tension on the belt. Place a tape or string between two points along the belt edge. Measure the belt length between these two points, and also the distance at the mid-point of the length between the belt edge and the tape or string.
The amount of bow is the ratio of the distance, midway between the above two points, between the belt edge and the tape or string, and the tape length between the two points. To express it in percent, calculate the ratio in hundredths and multiply by 100. For example the point-to-point length of 100 ft (30 m) has a bowed width of 18 in (450 mm) or 1.5 ft so 1.5/100 x 100 = 1.5% bow. Bow may not be troublesome. It may “pull out” when the belt is tensioned and operate satisfactorily.
The main causes of bow are:
a. Bowed fi lling yarns transversely across the fabric of the carcass; b. Crooked slitting of the belt into a narrower belt, and;
c. Storage of a belt on its edge when the fl oor is damp or water and/or other liquids reach the belt edge on the fl oor.
RIP TEST SPECIFICATION
1. Purpose
a. Test the ability of a given fabric carcass to resist ripping/tearing in the longitudinal direction once an object has become logged both in the belt and the system at the same time.
2. Sample Size
a. Sample Base - Length X Width - 12 in x 10 in b. Punch 3 - 5/8 in holes in the upper half of the sample with each hole being 2 in from the edges of the sample. c. Punch one 1 1/16 in hole in the center of the sample approximately 4 1/2 in from the end of the sample. (opposite of the 3 - 5/8 in holes)
d. This is a carcass test, to eliminate variable effects of covers the covers must be removed or a line must be cut in the direction of the rip. Using a special blade that is dulled on on the end cut a vertical line through the
1/2 in Holes
Top Testing JIG
1 1/16 in Hole
1 1/16 in Steel Rod Bottom Testing JIG top cover from the center of the 1 1/16 in hole to the
bottom of the sample. Flip the sample over and cut the same line through the pulley cover. Be careful to only cut the covers - Do not cut the carcass.
3. Sample Testing
a. Testing jigs, pictured in Figure 6-2 and 6-3, are required to both fasten and rip the sample during testing.
b. Sample is secured using the top three holes in a move- able jaw of lab testing apparatus and top testing jig (Figure 6-2).
c. Bottom Testing Jig (Figure 6-3) is placed into the bot- tom jaw of lab testing apparatus and sample is low- ered until the 1 1/16 in hole of the Jig and hole on the bottom half of the sample line up.
d. Place a 1 1/16 in diameter steel rod (Figure 6-3) through both the bottom testing jig and sample. The steel rod will facilitate the carcass rip.
e. Actuate the upper jaw of the test apparatus moving the sample upward with the steel rod being held in place by the bottom jig. The steel bar will start to rip through the carcass.
f. Continue test for at least 4 in and record all load peaks during the rip. The test is intended to break the fabric cords in the weft direction, document if any cords pullout instead of breaking.
4. Results
a. Report should include: i. Carcass Construction b. Recorded Results
i. Average of load peaks during 4 in tear ii. Documentation of any anomalies during test.
(cord pullout)
Figure 6-2.
Figure 6-3.
INTRODUCTION
This chapter is intended to serve as an introduction to splicing methods in general use. Belt users should consult belt and fastener manufacturers for more specifi c detailed information.
CONVEYOR BELT SPLICES USING MECHANICAL FASTENERS
A mechanical splice, while it does not afford the strength or permanence of a vulcanized splice, is typically used in the following conditions:
1. Belt tensions are low enough to meet the requirements for the belt under its mechanical splice rating. 2. Available downtime is only adequate for mechanical splicing.
3. Belt ends must be joined in cramped locations where vulcanized splices would be diffi cult to make. 4. The conveyor is an extensible or portable type which is frequently knocked down and moved. (Note: Typically mechanical fasteners offer a safety factor of 4:1)
When initial belt stretch on new belt is intended to be cut out before a vulcanized splice is made, it is common, particularly on a long-center conveyor requiring more than one splice, to make the last joint with fasteners and run the belt for a period of time. Then replace the mechanical splice with the fi nal vulcanized splice. This procedure helps to set the belt to the conveyor idlers and other equipment. It also helps to remove initial stretch, thereby ensuring against the premature necessity of shortening the belt with a vulcanized resplice.
When following this break-in procedure, suffi cient length must be reserved to provide for the fi nal vulcanized splice.
Metal Plate Fasteners
1. Double Plate Bolted Fasteners
Splices using double plate bolt fasteners are made with pairs of rigid metal plates bridging the joint on the top and bottom sides of the belt and fastened through the belt with bolts and nuts. The splice is prepared by punching or drilling bolt holes at the proper interval across the belt and distance from the belt ends. Proper spacing is best achieved by using metal templates sold by the manufacturer for each belt width and size of fastener.
Fastener plates are also made with prongs which are forced into the belt as the nuts are tightened.
For ordinary service, steel plates are used. Special stainless steel and alloy plates are available for use where increased resistance to corrosion, abrasion, anti-sparking, and nonmagnetic qualities are required. Templates and applicator tools are purchased from the fastener manufacturer according to the size of the fastener used. The fastener size is governed by the thickness of the belt and the diameter of the smallest pulley involved.
For belt covers over 1/8 in (3 mm) thick, fastener plates should be countersunk below the surface of the cover by buffi ng off an appropriate amount of cover. This results in the most effi cient anchoring of fasteners and permits the use of the smallest size fastener possible. Special countersinking equipment and advice are available from fastener manufacturers.
For general use, the joint for a splice made with double plate fasteners is prepared squarely across the belt at 90° to the belt centerline. The joint may also be made on a 45° angle for smoother pulley contact. Plates applied on a 45° angle will operate over pulleys 25% smaller in diameter than those on a 90° splice. The number of fasteners required on a 45° angle joint is approximately a third more than on a 90° joint. In applying the fasteners on a 45° splice, the plates are installed at right angles to the joint. Tension on the belt thus tends to tighten the joint.
2. Drive-on Plate Fasteners
Although drive-on plate fasteners are sometimes used to make belt splices, they are better for making quick, temporary repairs. They are fabricated with sharp teeth or rivets that are driven through the belt from the top surface on each side of the joint and clinched over on the bottom surface.