A Comparison of Effective Tension Calculation for Design Belt Conveyor between CEMA and DIN Standard

In the present era, many industries are demanding material transfer equipment that works maximally and cheaply. Belt Conveyor is one of the most efficient material transfer equipment compared to heavy equipment or other transportation equipment, because it can transport the material in large capacity. When designing conveyor belts, many industries want large transport capacity at low cost. One of the cost savings can be done with low motor power consumption. Many standards describe the effective tension calculation on the conveyor belt in detail with the parameters, since the effective tension calculation results are essential for determining motor power. This paper aims to analyze the effective tension on conveyor belts using CEMA 5th, CEMA 6th and DIN 22101 standards with case studies of 1000 TPH carrying capacity and 3 m/s conveyor speed. The difference between CEMA and DIN when determining the effective tension is on the use of coefficient of friction, because DIN uses a global coefficient of friction while CEMA uses different friction coefficients on idler, belt and material. This difference in coefficient of friction results in different ways of calculating the resistance being the accumulation of the effective tension. The result is an effective tension value using DIN 22101 standard of 22,148.16 N with motor power consumption of 66.5 kW, while effective tension value using CEMA 5 standard is 32.201.66 N with motor power consumption 96.47 kW, and effective tension value using CEMA 6 standard is 29,686.48 N with 89.06 kW motor power consumption.


Introduction
Material transport equipment is very important in this modern era of life, especially in helping a job to obtain maximum results.Material transport equipment serves to move material in certain areas, to a department, plant and plant, construction site, storage and loading.
Today, they are in most cases the most costeffective solution for handling bulk material mass flow over short and medium conveying distances.Despite the already advantageous costs for belt conveyor operation, there is still a desire to reduce these costs even futher [9].One of the cost savings can be done with low motor power consumption, where the motor power value is directly proportional to the effective tension value that occurs in a conveyor system.
Effective tension is defined as the sum of all the resistance of motion referring to the motor [6].The resistances that affect the effective tension are friction resistance due to friction between the belt, idler and material when the conveyor belt is running.In addition, the energy resistance or resistance caused by the load carried by the conveyor itself is a resistance that also refers to the motor.
In determining the effective tension of the conveyor belt, there are many standards that can be noticed by engineer such as; CEMA, DIN 22101, and so forth.
Standard is a norm which is usually a formal document that creates uniform engineering or technical criteria, methods, processes and practices.The two most common design methods used to calculate the effective tension on the conveyor belt are the Conveyor Equipment Manufacturer's Association (CEMA) method [1] [2] and the Deutsches Institute Normung (DIN) method DIN 22101 Standard [3].
Based on these problems, it is necessary to conduct research that aims to analyze the effective tension on the conveyor belt using standard variations DIN 22101, CEMA 5 th , and CEMA 6 th .Problems to be investigated in this research include: effective tension calculation analysis on belt conveyor capacity 1000 TPH using standard DIN 22101, CEMA 5th, and CEMA 6th, and determine difference of three standard in determining effective tension.The fundamental difference between DIN 22101 and CEMA 5 th is on the use of friction factor, where the DIN 22101 standard uses a single or global friction factor (f) while the CEMA 5 th standard distinguishes the coefficient of friction on idlers, belts, and materials (Kx and Ky).While CEMA 6 th further refine the friction factor of CEMA 5 th , where K x is changed to K is , K iV and C iW .The coefficient of friction is useful for calculating resistance due to friction that occurs in the belt, idler and material.

Belt conveyor data
No

Effective tension calculation result
Base on DIN 22101 methods, the result shown as figure above.

Figure 2. Graph of comparison of tension used DIN 22101 standard
The greatest tension occurs due to the energy load (elevation tension), where the value of the gradient tension (FSt) is 15441.2N.While the secondary tension (FN) is the smallest tension that occurs with the value of 2433.92N. The tension due to the primary tension (FH) occurs of 4273.04N.
CEMA 5 th methods, shows the results of the tension calculations that occur using the CEMA 6 th standard, where the greatest energy loss is caused by the tension lift or lower of material and belt (Th) with a value of 18926.8N. Tis, Tiw, Tbi and Tmz are the tension caused by friction on the idler, belt, and materials.The value of tension occurs due to the primary friction on belt conveyor (Tis, Tiw, Tbi and Tmz) is 3629.5 N.While the accessories tension (Tss, Ts, Tbc, Tdp and Tp) is occurs of 6298.33 N.

Comparison of Effective Tension Result
Table 6 shows the comparison of effective tension calculations using DIN 22101, CEMA 5th, and CEMA 6th standards.
The effective tension value is directly proportional to the motor power consumption value, so that the motor power value using DIN 22101 standards is 66.5 kW, the motor power value using CEMA 5th standard is 97.42 kW and the motor power value using CEMA 6th standard is 89.06 kW.Seen from the three largest energy loss standards caused by the tension of energy (height) and then followed by the primary tension and the smallest is secondary tension.

Result of maximum tension calculation with variation capacity using cema standard 6 th
The maximum tension is the largest tension that occurs in a conveyor belt system.The purpose of calculate the maximum tension in order to determine the construction specifications according to the maximum load value that occurred.Here is a graph showing the maximum load value on a conveyors variation with a conveyor speed of 3 m/s.

Figure 1 .
Figure 1.Scheme of conveyorTo analyze the effective tension calculation performed using computer program that is MATLAB 2008a.

For
DIN 22101 methods, ct = Temperature correction factor, where (ct = 1 at 20 o C, ct = 1.7 at T = -40 o C) f = Friction factor, value 0.01 < f < 0.04, based on operation and installation conditions.C = Secondary tension factor, based on conveyor length (C = 1.92 at 80 m, C = 1.05 at > 2 km) For CEMA 5 th methods, Kx = Idler friction factor (See the CEMA equation) Ky = Belt and material flexure factor (0.016 to 0.035), from CEMA table.Kt = Temperature correction factor, where Kt = 1 (0 < T < 40 o C), Kt = 3 (T = -40 o C) For CEMA 6 th methods, K is = Seal torsional resistance per roll (3 < K is < 7.25) based on the type of idler used.K iV = Torsional speed effect, (0.003 to 0.004), based on the type of idler used.K iT = Temperature correction factor (See the CEMA equation) C iW = Torsional load effect (0.00125 to 0.0029), based on the type of idler and bearing used.

Figure 3 .Fig 3 Figure 4 .
Figure 3. Graph of comparison of tension used CEMA 5 th standard

Figure 5 .
Figure 5. Graph of maximum tension as function capacity of belt conveyor

table 1 .
Using the data obtained we will analyze the differences between the DIN 22101, CEMA 5th, and CEMA 6th standard in designing and analyzing the effective tension to determine the motor power of the conveyor system.

Table 1 .
Conveyor industrial data