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Conveyor Components - Overview
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"
"
Idlers
"
Covers
Measuring Systems
"
"
"
Pulleys
Cleaners
Conveyor Structures
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EasyRun Rollers and Idlers - Concepts ®
Continuous transportation of bulk materials relies on a faultless conveyor system. A malfunction of just one conveyor component can delay all material production and therefore the reliability of each conveyor component is vital. The idler is one such component, and as idlers are present along the entire length of the conveyor, they demand particular attention. The idler is defined as the complete assembly comprising of the base frame and/or brackets, and roller or rollers. The roller is the heart of an idler and is defined as the revolving, cylindrical part of an idler, complete with shaft, bearings and seals. The idlers are attached directly to the conveyor frame. The belt follows this geometry and an effective profile for conveying bulk material is formed.
The three principal functions of each roller are to: " Support the belt " Rotate to keep the belt moving smoothly " Work reliably under the hardest of conditions, with low energy consumption, for as long as possible
It is our aim to deliver reliable rollers, the parameters of which exceed current industrial standards for all three of these principal functions. TRANZA saw the need to improve the design of rollers in line with technological advances and customer demand for more economical solutions. TRANZA has met this challenge with innovative designs of rollers and other components incorporating many features specifically developed within the company. Our research and development has led to the production of EasyRun® rollers which carry larger tonnages at greater speeds, consume less energy and are immune to aggressive environmental conditions (dirt, dust, rain, and large temperature differences).
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Rollers
EasyRun Product Range ®
- Flat rollers (type F)
- Training rollers (type T)
- Rubber-lagged rollers (type R)
- Return disc rollers (self-cleaning, type D)
- Impact rollers (type I)
- Return spiral rollers (self-cleaning, type S)
The rollers are standardised and designed according to ISO 1537, DIN 15207 and DIN 22112.Rollers according to BS and SABS or custom made rollers are available on request. Tranza is capable of delivering a range of special-design rollers: waterproof rollers, rollers for extreme climate conditions, rollers for extreme loading, high speed rollers and case-hardened rollers.
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Idlers
EasyRun Product Range ®
CARRYING SETS
RETURN SETS
TROUGHING
CT
VEE
CV
RV
CANTILEVER
CC
RC
TRAINING SETS
TCT
IMPACT SETS
IT
TRV
CENTRING SETS
SELF-CLEANING SETS
CCT
CCV
SRV
TCF
FLAT
CF
RF
SRF TRF
BRACKETS
CB
GARLAND
CG
RB
SRB
IG
SRG
The idlers are standardised and designed according to DIN 22107, and on request according to CEMA 502-2001 (B, C, D, E), SABS, BS. TRANZA is capable of delivering unique idlers made from fibreglass composites which combine high strength with low specific weight and excellent anticorrosion and antistatic properties. TRANZA also offers a range of special-design idlers: idlers for extreme climate conditions, for extremely heavy-duty applications, specific load distributions and zero gap idlers. 7
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Pulleys
Product Range
Drum style pulleys Lagging: - Steel (no lagging) - Rubber - smooth - herringbone pattern (clockwise sense) - herringbone pattern (anticlockwise sense) - diamond pattern
Wing style pulleys
-
Squirrel cage style pulleys
The pulleys are standardised and designed according to ISO 1536.
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Product Range
Accessories
Covers
Volume measuring system
- Corrugated steel (DIN 59231) - Organit rigid PVC
An optical belt sensor measures material on discharge conveyors by sending a beam. The receiving cameras pick up the sent beam and the computer checks and analyses the data.
Cleaners
Modular conveyor structures
- Carrying side cleaner
Structures are made from steel for difficult conditions in underground operations. Special corrosion-resistant, non-flammable structures made from pulltruded fibreglass composites, which are suitable for environments where there are risks of explosions, are also available.
- Return side cleaner
- Roof slung - Floor mounted - Combined (roof/floor)
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Rollers
The main components of a conveyor roller that influence its functional reliability and service life are:
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Design and Components A) Shell The shell is usually a steel tube of adequate thickness and diameter to match the required use. The shell is in direct contact with the belt and may wear excessively when rotational speed differs from belt speed. This can lead to shell thickness failure and finally to the shell collapsing. The wear can be attributed to: Misalignment (if rollers are not fitted perpendicular to the belt line rubbing of the belt over the roller shell surface results in premature failure). Contaminants (the action of grinding hard particles between the belt and the shell can cause an increase in the amount of wear on the shell).
certain risk of separation caused by either wear, corrosion, or mechanical failure of the joint between the shell and the end cap and this may result in a sharp edge of the end cap causing damage to the belt - "pizza cutter effect". The drawback of the inset weld is that some wear thickness is removed in the counterbore process. If the shell did wear in this area it would reach the end disc more swiftly than in the case of the exposed fillet weld roll.
B) Shaft The shaft is the load bearing element of the roller and must be adequately sized according to load and roller length. It is very important to ensure the bearing and shaft assembly operates under deflection conditions. The shaft is only supported at each end and therefore must accept the load from the shell to the bearings at each end. This results in shaft bending and angular deflection of the bearings. Solid accurately machined bright mild steel provides greater strength and less deflection. A circlip (F) positively locates the shell to the shaft and minimizes shaft float.
D) Internal sealing ring Serves for sealing the bearing and restricting the ingress of impurities from the internal area of the roller. It also prevents the escape of lubricating grease from the bearing into the internal area of the roller.
C) Bearing housing
E) Bearing
The bearing housing is made of deep drawn steel with a collar flange and calibrated bearing bore sized to a tolerance of ISO M7. The shape of the collar flange reinforces the corners of the shell. Plummer block housings are available on special request.
Only radial ball or tapered roller precision bearings are used. Ball bearings are more cost effective as tapered roller bearings have significantly higher CEMA Ai values (the force required to overcome frictional resistance and rotate rollers). On long horizontal conveyors this can represent noteworthy savings in power consumption as well as increasing the service life of associated drive components. Probably the most common type of roller failure is a seized bearing. Bearing seizure can be down to the following: - Selection of incorrect bearings may cause overloading of the bearing and its collapse. - Incorrect tolerances for the bearing fit may result in the bearing overheating.
If the manufacturer uses an end disc then the method of attaching the end disc to the shell is a very controversial issue in the industry. Some manufacturers butt the end cap up against the roll end and weld a fillet weld around the roll. Some manufacturers counterbore the end of the roll, inset the end cap inside the roll, and weld a fillet weld around the inside of the roll. With the first method there is
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Rollers
Design and Components
- If the bearings are misaligned (not fitted square and concentric with the shell of the roller) - Damage to the roller or idler frame when forced into idler frames on site - Seal failure resulting in contaminants entering the bearing
F) Circlip - Manufactured from hardened spring steel in compliance with DIN 471 - Minimises shaft float
Lubrication Lubricants in bearings have the following roles: To prevent direct contact between the rolling elements, race ways and cages To prevent bearing corrosion and wear To prevent the ingress of contamination To cool the bearings Lithium based grease is used to lubricate all parts of the sealing system for life.
Design of the roller
G) The labyrinth sealing system - The system comprises of several sealing elements which prevent contaminants from entering the bearing - Individual elements of the system are circular in shape with interlaid lips which form a labyrinth - The shape of the lips is designed to prevent the intrusion of contaminants into the bearing chamber without increasing rotational frictional resistance - The system has two parts - an inner labyrinth (H) and an outer labyrinth (I) protected by a cover (J) and a shaft ring (K) - Various types of labyrinth sealing system can be supplied depending on customers’ individual requirements
The diameter of a roller and its shell thickness can drastically affect a rollers life. Selecting a larger diameter reduces the rpm of the bearing as well as increasing the wearable surface area of the roller. Roller concentricity is important in providing smooth running and an even wear pattern for rolls and belt. A roll that does not rotate concentrically with the shaft will introduce vibration within the bearing that will decrease bearing life. A key issue in roller performance is drag. It is important to avoid drag as it can increases power consumption and affect the life of the roller. Accurate design of each detail of a roller and advanced technology used in final assembly are required to ensure the reliability and high performance of rollers and consequently conveyors.
Standard design with additional plate cover for harsh conditions
Standard design
Sealing System
Sealing System
Standard design with additional plate cover and rubber seal for very dusty and humid conditions
Sealing System
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Benefits of EasyRun Rollers ®
TRANZA concentrates on the critical points in roller design. Our efforts lead to the achievement of the best roller parameters in the industry. Throughout the design, manufacturing and testing process we utilise sound engineering principles to supply the best possible products to our customers. A fundamental parameter permanently evaluated by TRANZA is T.I.R. (Total Indicator Runout) which reflects imbalance and reduced life of rollers. Significant effort is focused on decreasing T.I.R. This approach produces TRANZA rollers with the following features: " Low vibrations, low noise " Reduced power consumption (to start and run the conveyor) " Min. 30.000 hours standard life time " Competitive prices Besides T.I.R. measurements Tranza also keeps a standard set of tests in order to benchmark its rollers with those of competitors so that it can continuously improve the performance of its rollers. This standard set of tests is used to monitor all issues which influence key features of EasyRun® rollers and includes: " " " "
Load capacity tests Wear tests Sealing against water and dust tests Start and run resistance tests
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The extraordinary level of balance, performance and life time achieved by TRANZA is a direct result of the attention it pays to the details of the design and manufacturing process: " Precision tolerances of the bearing housing (M7), shaft (h6) and bearing ensure the precondition of auto-alignment of the outer and internal bearing rings " Unique and precise assembly procedure provides for excellent balance of rollers and precision of alignment " Expertise in choosing correct components esp. bearings for specific applications " The bearing and shaft assembly operates under deflection conditions " Variety of seals " Shafts are manufactured from highly precise steel rods " Highly precise steel tubes are used for shells " Calibrated collar flange bearing housings avoid the "pizza cutter effect" and reduced wear thickness and result in higher roller load capacity " Rollers and their components are permanently tested throughout the manufacturing process " Every roller is test run after final assembly at an equivalent belt speed of nine (9) metres per second.
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Rollers TABLE 1: Type Codes
Z - 111 x 2222 / BBBB / X / YY.3333 / 444 x 55 Z
Type code (see Table 1)
111
Diameter of the shell in mm
2222
Length of the shell in mm
BBBB
Bearing code according to ISO 15
X
Shaft end code (see Table 2)
YY.3333
Coating code (see Table 3) followed by RAL colour code
444
Diameter of rubber lagging/ring/disc (for R,I,D rollers only) in mm
55
Number of rubber rings (optional - for R and D rollers only)
CODE
DESCRIPTION
F
Flat
R
Rubber-lagged
I
Impact
T
Training
D
Return disc (self-cleaning)
S
Return spiral (self-cleaning)
EXAMPLE:
Flat roller, diameter of shell 89 mm, length 600 mm, bearing 6204, double flat shaft ends, yellow polyester powder coating RAL 1003: F - 089 x 600 / 6204 / A / PP.1003
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EasyRun Ordering Codes ®
TABLE 2: Shaft End Codes
TABLE 3: Coating Codes
CODE
DESCRIPTION
CODE
DESCRIPTION
CODE
DESCRIPTION
A
Double flat
H
Single flat
PP
Polyester powder
B
Internal double flat
I
Internal single flat AC
Anti-corrosive synthetic primer coat
WD
Water diluted
C
Bush
J
Plain
D
Garland
K
Plain reduced
E
External thread + nut
L
Internal reduced plain*
F
G
External thread
Internal thread
M
SZ
Painting system: zinc-phosphate primer coat + synthetic-polyurethane top coat
SE
Painting system: two-component epoxy primer coat + epoxy-polyurethane top coat
External reduced thread
*For training rollers only
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Idlers The idler is comprised of the base and/or brackets and one or more rollers and is fixed to the conveyor structure. There are several types of idlers and each has a different function and different location on the conveyor.
Carrying Sets The first group of idlers covers carrying sets which support the loaded section of the belt and move the material. They are located in the upper part of the conveyor.
Carrying Troughing (CT) " Most carrying sets have a troughing shape which allows greater amounts of material to be conveyed. These shape the belt to prevent spillage and are available with 20°, 30°, 35° and 45° trough angles with equal or unequal roller lengths. Troughing carrying sets have 3 rollers supported within the base frame which is fixed to the conveyor structure. Normal spacing is 1 to 1,6 m.
Carrying "Vee" (CV) " This type of idler is used in less demanding environments where belt speeds are generally less than 2,5 m/s. It is designed for transporting small grain material (gravel, sand). Owing to the shape of the trough it has a lower transportation output than a troughing idler however this is compensated for by its lower cost (amongst other things there is a 1/3 lower need for rollers).
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EasyRun - Types and Functions ®
Carrying Cantilever (CC) " This idler comprises of a central bracket and two rollers without side brackets. It is designed for less demanding environments and short length conveyors (e.g. discharge conveyors of screeners). They are advantageous due to their significantly lower demand on space.
Carrying Flat (CF) " These have a single roller supported by two brackets fixed to the conveyor structure. They are used in picking, sorting and unit materials handling applications. Load capacity is much less than that of troughing idlers because of the long shaft length and only two bearings.
Carrying Bracket (CB) " These are designed for use in low speed belt conveyors for light loads. Their simple low-weight design means they are low priced.
Carrying Garland (suspended) sets (CG) " Consists of several (3 or 5) rollers, attached together by a chain link. Contrary to troughing sets the maximum angle of the side rollers is 60°. This design leads to greater flexibility of the structure which results in improved belt centring, load containment, higher working speeds and load capacity, better absorption of dynamic stresses during conveying large bulky material, less shut down time and lower installation and maintenance costs.
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Idlers Return Sets These are located in the bottom part of the conveyor and support the belt on its return from the discharge point to the tail pulley. The designs of return sets are essentially the same as for carrying sets:
Return "Vee" (RV) " Used for the return branch of larger width belt conveyors. It is fitted with a pair of flat rollers which are angled at 10° from the horizontal.
Return Cantilever (RC) " This has the same structure as the carrying cantilever but is used for the return branch. It is used for smaller width belts and lower speeds. Its advantage is that it is attached centrally therefore not requiring a supporting steel side structure as required by the other types of idlers.
Return Flat (RF) " This idler is for supporting the return branch of the belt where a single roller table is sufficient from the technical point of view but where a set of brackets are not sufficient from the strength point of view.
Return Bracket (RB) " This is one of the most popular means used for mounting rollers to support the return branch of the belt. It is preferred for belts up to 1400 mm in width thanks to its simple design and affordable price.
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EasyRun - Types and Functions ®
Special Sets These are designed to have different functions. Each function determines the design of the idler but the actual shapes of carrying and return sets generally remain the same.
Impact sets " Their function is to ensure maximum belt protection for the optimum service life. Impact idlers are positioned at the loading points where bulk material falling onto the belt could cause damage to it. Impact sets are equipped with rubber-lagged rollers or impact rollers with a number of rubber rings of appropriate thickness and resistance.
Impact Troughing (IT) " These idlers are designed for use in places where material is dropping from a height (hoppers) " Two types are produced: - Section frame (same as CT idlers) - Tube frame (special double-pipe structure) " Use of a specific type depends on loading parameters (loading capacity, grain size) " Both types are fitted with rubber-lagged or impact rollers for damping the impacts of falling material
Impact Garland (IG) " These are designed for use in places where material is falling from a height (hoppers) onto conveyors fitted with garland sets. " They are fitted with impact rollers
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Idlers Carrying or return belt training sets (TCT, TCF, TRF, TRV) Troughing or flat idlers assist in keeping the conveyor belt centred on the conveyor when temporary or transient conditions could result in belt misalignment. Two small side rollers attached vertically to the base frame provide for self-alignment of the belt. Training sets are generally spaced 30 m apart and not within 15 m of the head or tail pulley. The effectiveness of trainer sets is enhanced by the use of urethane rollers.
Centring idlers Centring Carrying Troughing (CCT) " These idlers are used for supporting the carrying belt " They have a centring effect caused by a slight incline of the axes of the side rollers (approx. 2°) " They have the same function as training idlers but they are used on smaller dimension belts (for belt lengths up to 100 m). If they are used they should be fitted along the whole length of the conveyor.
Centring Carrying "Vee" (CCV) " These are designed for supporting the carrying belt. " They have a centring effect caused by a slight incline of the axes of the rollers (approx. 2°) " They have the same function as training idlers but they are used on smaller dimension belts (for belt lengths up to 100 m). If they are used they should be fitted along the whole length of the conveyor.
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The correct choice of idlers is essential for proper performance of the conveyor. The following parameters play a key role in choosing idlers:
Load parameters " Characteristics of the load (lump size, material abrasiveness, humidity) " Total load capacity " Type of conveyed material
Environmental requirements " Temperature range " Others
Conveyor parameters " Belt speed " Belt type " Position/function of the idler in the conveyor Decades of experience allow our experts to guide our customers through the whole idler selection procedure. It is part of Tranza’s mission to ensure that you choose the correct idlers.
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Idlers TABLE 4: Idler shape/function codes
AAA - B - 1111 / 22 / C / DD.3333
CODE C
DESCRIPTION A
R
R
Y
I
N
G
AAA
Idler shape/code (see Table 4)
B
Frame design code (see Table 5)
CT
Carrying troughing
B
0 for garlands
CV
Carrying "Vee"
1111
Belt width in mm
CC
Carrying cantilever
22
Angle of rollers in ° for troughing, vee and cantilever idlers
CF
Carrying flat
22
00 for flat idlers and brackets
CB
Carrying bracket
22
Number of rollers followed by hanger code for garlands (see Table 6)
CG
Carrying garland
C
Roller mounting code (see Table 7)
DD.3333
Coating code (see Table 8) followed by RAL colour code
EXAMPLE:
Carrying troughing idler, belt width 650 mm, rollers angle 20°, roller mounting double flat, hot dip galvanised: CT - S - 650 /20 / A /HG
R
E
T
U
R
N
RV
Return "Vee"
RC
Return cantilever
RF
Return flat
RB
Return brackets
S
S
E
T
E
T
S
S
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EasyRun Ordering Codes ®
CODE T
DESCRIPTION R
A
I
N
I
N
CODE G
S
E
T
S
S
E
DESCRIPTION L
F
C
L
E
A
N
I
N
TCT
Training carrying troughing
SRV
Self-cleaning return "Vee"
TCF
Training carrying flat
SRF
Self-cleaning return flat
TRV
Training return "Vee"
SRB
Self-cleaning return bracket
TRF
Training return flat
SRG
Self-cleaning return garland
I
M
P
A
C
T
S
IT
Impact troughing
IG
Impact garland C
E
N
T
R
I
N
E
T
G
S
E
T
S
S
TABLE 5: Frame design codes G
S
E
T
S
CODE
DESCRIPTION
CCT
Centring carrying troughing
T
Tube frame design
CCV
Centring carrying "Vee"
S
Section frame design
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Idlers
Ordering Codes
TABLE 6: Garland hanger codes
TABLE 7: Roller mounting codes
CODE
DESCRIPTION
H
Hook
O
Open link
P
Stirrup type
C
DESCRIPTION
A
Double flat
B
Internal double flat
C
Bush
D
Garland
E
External thread + nut
F
External thread
G
Internal thread
H
Single flat
I
Internal single flat
J
Plain
K
Plain reduced
L
Internal reduced plain
Chain
B
Brace
TABLE 8: Coating codes CODE
CODE
DESCRIPTION
PP
Polyester powder
AC
Anti-corrosive synthetic primer coat
WD
Water diluted
SZ
Painting system: zinc-phosphate primer coat
SE
Painting system: two-component epoxy primer coat + epoxy-polyurethane top coat
HG
Hot dip galvanised
M
External reduced thread
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Pulleys Pulleys are the main elements providing the transmission of torque from the drive and ensuring that belts remain taught. They have different functions in conveyors depending on their position in the conveyor layout (drive/ head, return/tail, tension, snubbing, redirection): " Head/Drive Pulley is located at the discharge terminus of the conveyor. It provides the driving force for the conveyor. In order to increase pulley life and traction it often has a larger diameter than other pulleys in the conveyor and is lagged. " Return/Tail Pulley is located just before the loading point of the conveyor " Take-Up Pulley provides gravity force adjustments to maintain the necessary slack side belt tension " Take-Up Bend Pulley is used to change belt direction on the slack side of the conveyor. In order to increase belt life it is often lagged. " Snub Pulley tightens the belt giving more surface contact between the belt and pulley surface and is located immediately behind the drive pulley. Pulley diameter has a significant influence on the required power of the drive and service life of the belt. The pulley diameter is dependent on the chosen type of belt and thus on the material to be transported (type, grain size), the capacity (amount of t/hour, conveying speed), working environment, structural design of the conveyor.
Pulleys have three basic design styles depending on operating conditions and their function in the conveyor system:
Drum style pulleys Can be used at any location. It consists of a rim shell, 2 end discs and 2 shaft locking assemblies.
Wing style pulleys Can be used as a tail pulley and on gravity take-up assemblies. Helps prevent material build up and belt damage from transported materials. It consists of face bars, fins, gussets and locking assemblies.
Squirrel cage style pulleys Can be used in the same positions as wing pulleys for particular applications where very wet materials are conveyed and where the inner surface of the belt gets very dirty.
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The following parameters are required for designing a pulley:
1) Width of conveyor belt 2) Quality of conveyor belt 3) Conveyed amount of material (type of material) 4) Conveying speed 5) Length of conveyor and degree of incline 6) Type of drive station (single pulley x two-pulley) 7) Number of drive units 8) Power of drive units, weight 9) Bearings of drive units – coupling with pulley 10) Start up – starting drive units 11) Means of clamping the belt 12) Pulley diameter, bearing pitch, required service life of bearings 13) Working environment 14) Type of pulley, location along conveyor belt
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Selecting Rollers
Diameter (mm)
Belt width B
Roller length (mm) Bearings
Max. belt speed m/s
*)
400
63,76,89
108/63
108/76
400
6204
500
250
160
3.5
500
63,76,89
108/63
108/76
500
6204
600
315
200
3.5
650
63,76,89
108/63
108/76
650
6204
750
380
250
3.5
800
89,108
108/63
108/76
800
6204
950
315
3.5
1000
108,133
133/89
133/89
1000
6204
1150
600
380
3.5
1200
133
133/89
133/89
--
6204
1400
670
465
3.5
133
159/89
--
1200
6305
1400
670
465
5.5
133
159/89
--
--
6306
1400
670
465
7.5
133
133/89
--
--
6204
1600
750
530
3.5
133
159/89
--
1400
6305
1600
750
530
5.5
133
159/89
--
--
6306
1600
750
530
7.5
1600
159
194/108
--
1600
6308
--
900
600
7.5
1800
159
194/108
--
1800
6308
--
1000
670
7.5
2000
194
245/133
--
2000
6310
--
1150
750
7.5
1400
--
* Carryng idler roller lengths only apply up to belt widths of 650 mm. Return idler roller lengths apply to belt widths greater than 800 mm. )
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