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U.S. RUBBER CORP.

 

 

Text Box:

U.S. RUBBER CORPORATION  - 211 NORTH LOOP 336 EAST -  CONROE TX  77301     SALES 800-872-3587

KEY ASPECTS OF BELT SELECTION

CUSTOM

   BELTING   

           KEY

            POINTS

Impact Rating - The impact rating of a belt should be considered relative to the material to be conveyed, the manner in which the material is introduced to the belt and  the attention paid to absorbing the impact with  the conveyor system instead of the belt.  It is not unusual for a severe impact requirement to dictate a belt construction with considerably higher working  tensions than otherwise normal due to high levels of impact from the product carried and the system design.

 

System Take-up Capabilities - In many cases, conveyor systems have adequate take-up capabilities.  However, it is not uncommon to find a conveyor that for one reason or another does not have the take-up  space to accept normal belt elongation. In these cases, it is preferable to use a carcass construction that has a higher modulus than that normally found in Nylon tensile carcass materials. Polyester, Aramid and Steel offer increasingly higher modulus tensile members for those systems with take-up limitations

 

Since Aramid and Steel carcass belts normally require longer lead times and are not generally carried as stock items, it is sometimes more cost effective and practical to utilize higher tension Polyester plied carcass belts or Straight Warp belts in these applications.

 

Cover Selection - Cover compounds come in many varieties and are selected to be compatible with the service they are going to perform  and the atmosphere in which they are to be operating. The compounds available from U.S. Rubber are listed under the Cover Compound section of this catalog.

 

In addition to selecting the correct cover compound, it is also essential to determine the proper cover thickness required for the service desired. The following recommended cover thickness guide has been  provided for assistance in making that decision.

RECOMMENDED COVER THICKNESS

Text Box:

U.S. RUBBER CORPORATION  - 211 NORTH LOOP 336 EAST -  CONROE TX  77301     SALES 800-872-3587

 

KEY ASPECTS OF BELT SPECIFICATION AND BELT SELECTION

U.S. RUBBER CORP.

 

 

Transition Distance - Transition distance is defined as the distance from the center line of the first fully troughed idler system to the center line of the head or tail pulley. The distance from the pulley  to the top of the wing roll is greater than the distance from the pulley to the center roll of the idler.

 

This difference in distance creates higher tensions in the edge of the belt than t he center of the belt, which can create belt problems.  The most common of these problems are:

 

                         If transition  is too short at the head pulley

                                  Idler Gap Failure

                                  Splice failure (from the outside in)

                                  Belt folding up in the center and folding over on itself.

Minimum Pulley diameters - When a belt travels around a pulley, the outer plies of the carcass traverse a greater distance than the inner plies. If the pulley diameters are too small for the belt, the inner plies may be forced into compression resulting in ply separation and premature failure of the belt.  Minimum recommended pulley diameters for each belt specification are shown in the belt specification tables of this catalog.

Troughability  -  If a belt's transverse  rigidity is too stiff, it will not conform to the troughing idlers resulting in the inability to track the belt properly.

 

Excessive transverse rigidity is generally the result of excessive belt thickness, skim coats that are too thick or a belt that is too narrow in proportion to its thickness and stiffness.

 

A troughability chart for each belt specification is shown in the belt specification tables of this catalog.

 

Load Support -  A belt must have enough carcass transverse rigidity to ensure the proper bridging of the

 idler junction gaps, there by eliminating the possibility of belt fatigue and failure in these areas.

 

Load support information  for all belt specifications is shown in the specification tables of this catalog.

NOTE: The Rubber Manufacturers Association “RMA” has established  a limit of GAP between carrying idler rolls for troughed conveyors of 10mm.  Further, it is prudent that the overall belt gauge should be greater than 1/2 this gap.

NOTE: The minimum pulley diameter requirements for mechanical fasteners is generally more restrictive than for the belting itself. When using mechanical fasteners, wing pulleys should be 25% greater in diameter than the diameter normally recommended.

U.S. Rubber Corp. can create custom belts to suite your needs.  Our compounds are designed using the highest quality material which adds to the longevity of the belt you purchase.

 

Our sales team will work with you making sure that key areas are covered when we design your custom belting.  Some of the important areas that will be covered are listed below. 

CUSTOM BELTING KEY POINTS

Text Box:

U.S. RUBBER CORPORATION  - 211 NORTH LOOP 336 EAST -  CONROE TX  77301     SALES 800-872-3587

WEIGHTS OF MATERIAL (Density)

U.S. RUBBER CORP.

 

 

Text Box:

U.S. RUBBER CORPORATION  - 211 NORTH LOOP 336 EAST -  CONROE TX  77301     SALES 800-872-3587

U.S. FACTORY OPERATIONS IN CONROE TEXAS

RECOMMENDED COVER THICKNESS

Class of Material

Examples

Minimum top

A. Favorable

B. Conditions

B. Adverse

Condition

Minimum

Bottom Covers

Non-Abrasive

Wood Chips, Pulp

Grain, Fine Coal

1/16”

1/8”

1/32”

Mildly Abrasive

Sand, Earth, Coal

(Bituminous), Rock

Under 3”

1/8”

3/16”

1/16”

Abrasive

Coke, Sinter, Iron

Copper and Gold Ore,

Crushed Stone

3/16”

1/4”

1/16”

Heavy, Abrasive

Iron, Copper, Zinc Ores, Limestone under 9”

1/4”

3/8”

1/8”

Heavy, Large Lumps

Sharp Abrasive

Trap Rock, Quartz, Glass

Cullet, Sharp Ore + 9

3/8”

1/2”+

3/16”

 

Lbs Per Cu Foot

Angle Repose

 

 

Lbs Per Cu Foot

Angle

Repose

Alumina

50-65

22

 

Kaolin clay, 3 inches and under

63

35

Aluminum Oxide

70-120

29

 

 

 

 

Ammonium Nitrate

45

30-44

 

Lead Ores

200-270

30

Ashes, Coal, Dry, 3 inches and under

35-40

45

 

Lead Oxides, Pulverized

200-250

30-44

Ashes, Coal, Wet, 3 inches and under

45-50

45

 

Limestone, Agricultural , 1/8 inch and under

68

30-44

Ashes, Fly

40-45

42

 

Limestone, Crushed

85-90

38

Asphalt, Binder for paving

80-85

 

 

 

 

 

 

 

 

 

Manganese Ores

125-140

39

Bagasse

7-10

45

 

Marble, Crushed, 1/2 inch and under

80-95

30-44

Bauxite, Mine Run

80-90

31

 

Mica, Flakes

17-22

19

Borax, 1/2-inch screening

55-60

30-44

 

Molybdenum Ore

107

40

Borax, 3 inches and under

60-70

30-44

 

Nickel -Cobalt, Surface ore

80-150

30-44

 

 

 

 

 

 

 

Carbon Black, Pelletized

20-25

25

 

Phosphate Rock, Broken, Dry

75-85

25-29

Carbon Black, Powder

4-7

30-44

 

Potash (Muriate), Mine Run

75

30-44

Cast Iron Chips

90-120

45

 

Potassium Chloride, pellets

120-130

30-44

Cement, Portland

72-99

30-44

 

Pyrites, Iron, 2 to 3-inches lumps

135-145

20-29

Cement, Clinker

75-95

30-40

 

 

 

 

Cinders, Blast Furnace

57

35

 

Quartz, 1-1/2 to 3-inch lumps

85-95

20-29

Cinders, Coal

40

35

 

Rice, hulled or polished

45-48

19

Clay, Dry, Fines

100-120

35

 

Rock, Crushed

125-145

20-29

Clay, Dry, Lumpy

60-75

35

 

 

 

 

Coal Bituminous, mined, run of mine

45-55

38

 

Salt, Common Dry, Fine

70-80

25

Coal, Bituminous, stripping, not cleaned

50-60

 

 

Salt Cake, Dry, Coarse

85

36

Coffee, Green Bean

32-45

30-44

 

Sand, Bank, Dry

90-110

35

Coke, Petroleum, Calcined

35-45

30-44

 

Sand, Foundry, Prepared

80-90

30-44

Concrete, Cinder

90-100

 

 

Sand, Silica, Dry

90-100

20-29

Copper Ore

120-150

30-44

 

Slag, Furnace, Granular, Dry

60-65

25

Corn, Shelled

45

21

 

Slate, Crushed, 1/2 inch and under

80-90

28

 

 

 

 

Soda Ash, Heavy

55-65

32

Earth, As Excavated - Dry

70-80

35

 

Sodium Aluminate, Ground

72

30-44

Earth, Wet, Containing Clay

100-110

45

 

Sodium Nitrate

70-80

24

 

 

 

 

Soybeans, Whole

45-50

21-28

Feldspar, 1/2-inch screenings

70-85

38

 

Sugar, Raw, Cane

55-65

45

Feldspar, 1-1/2 to 3 - inch lumps

90-110

34

 

Sugar, Refined, Granulated, Dry

50-55

30-44

Foundry refuse , old sand cores, etc

70-100

30-44

 

Sugar, Refined, Granulated, Wet

55-65

30-44

 

 

 

 

Sulfate, Crushed, 1/2 inch and under

50-60

30-44

Glass batch (textile fiber glass)

45-55

0-10

 

Sulfate, Powdered

50-60

30-44

Grain, distillery, spent, dry

30

30-44

 

Sulfate, 3 inch and under

80-85

30-44

Graphite Ore

65-75

30-44

 

 

 

 

Gravel, Bank Run

90-100

38

 

Taconite, Pellets

116-130

30-44

Gravel, Dry, Sharp

90-100

30-44

 

Titanium Dioxide

140

30-44

Gypsum, 1 1/2 to 3 Inch Lumps

70-80

30

 

Urea Pills, Dry

43-46

25

 

 

 

 

Wheat Germ, Dry

18-28

20-29

Ilmenite ore

140-160

30-44

 

Wood Chips

10-30

45

Iron Ore

100-200

35

 

Wood Shavings

8-15

 

Iron Ore Pellets

116-130

30-44

 

Zinc Ore, Crushed

160

38