Splicing station and an unreeling device in front of a conveyor.
Unreeling a flat reel
PRESPLICING
The splice station is set up directly behind the unreeling device. The first part length is pulled off the drum and is stacked in long loops between the vulcanizing station and the conveyor.
After completed stringing, the final (endless) splice will be carried out on top of the conveyor.
Belt put into loops after splicing, prior to stringing.
STRINGING ARRANGEMENTS
Belt stringing arrangement for a slope conveyor.
Stringing of an overland conveyor belt (video)
4 - 6 = Clamps
3 = Table
2 = Vulcanizer
1 = Belt reels
BELT CLAMPING
The coefficient of friction has a decisive influence on the frictional connection between the clamping jaws and the conveyor belt.
As can be seen from the table below, it is highly influenced by the operating conditions.
Coefficients of friction as per DIN 22101 resp. ISO 50048
Operating conditions
dry
wet (clean water)
wet (with clay)
Smooth steel
0,35 up to 0,4
0,1
0,05 up to 0,1
Polyurethane friction lining
0,35 up to 0,4
0,35
0,2
Rubber friction lining
0,4 up to 0,45
0,35
0,25 up to 0,3
Ceramic friction lining, porous
0,4 up to 0,45
0,35 up to 0,4
0,35
Clamping jaws with ceramic friction lining offer an optimum of frictional connection and load transmission under all operating conditions. The design of such a clamp should be based on a coefficient of friction of µ = 0,3 - 0,35.
Depending on the condition of the belt surface, the friction linings may become "smooth" after a number of pulling-in cycles. After completion of the work, it should be checked if the structure of the friction linings still have sufficient roughness. If necessary, they have to be thoroughly cleaned, e.g. with a steam jet.
When a new belt is produced for an inclined drift conveyor, silicone spray should not be used as separating agent, since this can considerably reduce the coefficient of friction between clamping jaws and the belt already after a short period of operation.
Task Definition
Belt width
B
1400 mm
Required holding force
Hreq
1400 kN
Coefficient of friction
µ
0,3
Safety factor
S
≥ 2,0
Basic data of clamp
Number of disk spring packages
n
B / 200
Pressure per disk spring package
p
142 kN
Calculation of number of clamp sections
Required pressing force of the clamp (minimum)
Pmin
Hreq/2µ*S
= 4667 kN
Number of clamping sections
N
Pmin / n*p
= 5 (rounded up)
Calculation of the clamping data
Effective pressing force of the clamp
Peff
N*(n*p)
= 4970 kN
Maximum permissible holding force
Hper
Peff*2µ
= 2982 kN
Safety factor
S
Hper/Hreq
= 2,13
Surface pressure on the belt
PF
(p*n*1000)/(B/10*WoFL)
= 236,7 N/cm²
The virtual friction factor for pulling a conveyor belt depends on many parameters. However, a good rule of thumb for long distance conveyors is to use 0.05 for inclined or horizontal conveyors and 0.01 for downhill conveyors plus some kN for the intitating force.
