Belt conveyor maintenance manual

1. Scope and purpose

This practical guide is designed for qualified technicians and maintenance engineers who are responsible for the operation and maintenance of belt conveyor systems in industrial environments. It covers critical aspects of maintenance such as adjusting belt centering, inspecting splices, measuring and adjusting belt tension, and replacing rollers.

Regular performance of these procedures is essential to ensure safe, efficient, and trouble-free operation of conveyor equipment, minimize unplanned downtime, reduce operating costs, and extend component life. It is recommended to carry out these works according to the scheduled preventive maintenance schedule, or immediately when deviations are detected in the conveyor.

2. Safety measures

Performance of belt conveyor maintenance work is associated with a high risk of injury due to the presence of moving parts, significant weight of equipment and high energy. Compliance with security measures is critical and mandatory.

• LOCKING / POSTING OF WARNING SIGNS (LOTO): Before starting any maintenance work on the conveyor, it is necessary to completely de-energize its drive and block the mechanisms that can move. Use standard LOTO (Lockout/Tagout) procedures in accordance with the company's internal instructions and the requirements of DSTU EN ISO 14118. Make sure that the energy sources (electrical, hydraulic, pneumatic, gravity) are completely disconnected and locked.
• PERSONAL PROTECTIVE EQUIPMENT (PPE): Mandatory use of the following PPE: safety glasses (DSTU EN 166), protective gloves (corresponding to the type of work: mechanical, chemical), protective shoes (DSTU EN ISO 20345), protective helmet (DSTU EN 397), as well as protective clothing that does not have loose elements that can catch on moving parts parts
• WORK AT HEIGHT: When performing work at height, use certified insurance systems and means of personal protection against falling from a height (DSTU EN 358, DSTU EN 361, DSTU EN 363).
• MOVING PARTS: Never work near moving parts of the conveyor. Make sure all moving parts are stopped and secured before starting work.
• DUST AND MATERIALS: Provide adequate ventilation and use respirators (PPE EN 149) when working with loose materials that can form dust. Avoid breathing dust.
• THERMAL RISKS: Conveyor components (eg bearings, motors) can be hot. Use thermal gloves when working with hot surfaces.

3. Necessary tools and materials

Before starting work, make sure that all necessary tools and materials are available and in working order.

4. Pre-release checklist

Perform visual inspection and checks before starting detailed maintenance.

5. Step-by-step procedure

5.1. Checking and adjusting the centering of the tape

Incorrect centering of the belt leads to wear of the edges, damage to the conveyor frame, spillage of material and significantly shortens the service life of the belt.

1. Inspection Preparation:

   • Turn off the power to the conveyor and perform the LOTO procedures. This is required for safe viewing.
   • Clean the tape and rollers of any material that may be stuck to the centering.

2. Initial visual inspection (with care, under control):

   • After receiving permission for a short run (without material), start the conveyor.
   • Watch the tape move for 5-10 minutes. Pay attention to the areas where the tape goes away from the center.
   • Determine if the tape runs in one direction along its entire length or if it is a localized problem.
   • Common error: Incorrect identification of the problem area. Always start the search for the cause from the area where the tape is loaded to the end of the conveyor.
   • Turn off the power again and do LOTO.

3. Troubleshooting and troubleshooting:

   • Belt slack: If the belt is slack, it can interact unevenly with the rollers. Check the tension (see 5.3).
   • Material Sticking: Material sticking to rollers or drums changes their effective diameter, causing belt displacement. Clean them up.
   • Uneven load: Check the condition of the material feed devices to see if they are creating a one-sided load.

4. Centering adjustment using roller supports:

   • Determine which way the tape goes. To return the tape to the center, the roller supports must be deflected to the side opposite to the direction of tape movement.
   • For example, if the tape goes to the right in the direction of movement (on the upper branch), it is necessary to shift the roller (or the entire roller support) so that its axis is slightly turned to the left (in the direction of the tape).
   • Use spanners to loosen the roller mounts (usually two bolts on one side).
   • Use step adjustments to adjust by 2-3 mm. Move one end of the roller support by 2-3 mm.
   • Tighten the roller support fasteners. The recommended tightening torque for M16 bolts is 120-150 Nm, for M20 - 200-250 Nm. Check with a torque wrench.
   • Rerun the conveyor for a short time to evaluate the effect of the adjustment.
   • Common mistake: Over-adjustment. Always make small changes and test the result before making further adjustments.
   • Adjust the bearing rollers (upper branch) first, then the turning rollers (lower branch).

5. Checking the centering of the drive and tension drums:

   • Using a measuring tape and a square, check the parallelism of the axes of the drums and the perpendicularity to the axis of the conveyor. Permissible deviation from perpendicularity: no more than 1 mm per 1 meter of tape width.
   • Adjustment is made by moving the bearing units of the drums. This is a more complicated procedure and requires caution.

6. Visual indicator of correctness: The tape is evenly located in the center of the conveyor frame, does not touch the side limiters and roller supports, the edges of the tape are not damaged. The movement of the tape is stable without visible oscillations.

5.2. Inspection of tape connections (splices)

The belt connection is one of the weakest links of the conveyor. Damage to it can lead to belt breaks and significant downtime.

1. Safety:

   • Turn off conveyor power and perform LOTO procedures.
   • If possible, provide access to the splice from both sides of the tape (top and bottom branches).

2. Visual inspection of mechanical connections (locks):

   • Inspect all metal elements of the connection for corrosion, cracks, deformations, bends.
   • Check the reliability of fastening of all bolts, rivets or other elements. Look for loose or missing fasteners.
   • Check for excessive wear on metal parts from rubbing against rollers or material. Allowable wear: no more than 20% of the original metal thickness.
   • Inspect the ends of the tape near the joint for delamination, cuts, and rubber wear.
   • Measure the gap between the ends of the tape at the joint. Optimal gap: 0.5-1.0 mm. An excessive gap (>2 mm) indicates a weak connection.
   • Common mistake: Ignoring small defects. Small damage quickly turns into serious damage.

3. Visual inspection of vulcanization joints:

   • Inspect the entire seam area for delaminations, cracks, bubbles, and rubber peeling.
   • Feel the seam, checking its elasticity and uniformity. The seam should be uniform in the thickness of the tape.
   • Pay attention to any signs of separation of the edges of the seam. The presence of a gap > 0.5 mm is unacceptable.
   • Inspect the outer edges of the seam for cracking or drying out of the rubber.

4. Defect actions:

   • Mechanical connections: Replace damaged or missing fasteners. Check the tightening torque of all bolts. In case of significant wear of metal parts or delamination of the tape near the joint - a complete replacement of the joint is necessary.
   • Vulcanizing joints: If delaminations or cracks longer than 50 mm are detected, it is recommended to repair the vulcanization or completely replace the joint. Small cracks can be repaired with special repair compounds.

5. Visual indicator of correctness: The tape joint appears uniform, with no visible damage, protrusions, delaminations or gaps. All fasteners are securely tightened.

5.3. Tape tension measurement

Proper belt tension is critical to preventing slippage, vibration, and excessive wear of the belt and components. The tension must comply with the recommendations of the conveyor manufacturer and DSTU ISO 5048.

1. Safety:

   • Turn off conveyor power and perform LOTO procedures.
   • Make sure the tensioning station is locked against accidental activation (for counterweight systems).

2. Preparation:

   • Clean the tape and rollers from sticking material.
   • Choose an area to measure the tension, usually on the lower (swing) arm of the conveyor, away from the drums and the tension station. The length of the measured area should be at least 3-5 meters.

3. Sag measurement method (for conveyors without specialized sensors):

   • Measure the distance between the two supporting rollers on the lower branch (span L).
   • Attach a straight metal ruler or stretch a string between the top points of these two rollers.
   • Measure the maximum vertical tape sag (h) mid-span from the string line to the top surface of the tape.
   • Calculate the percentage of sag: (h / L) * 100%.
   • Common values: for rubber fabric tapes, the optimal sag is 1.5% - 2.5% of the span length. For steel wire bands - 0.5% - 1.0%. Always refer to the manufacturer's documentation.
   • Common mistake: Measuring on an area with uneven loading or material sticking.

4. Method to measure tension using strain gauges or dynamometers (if installed):

   • Use the manufacturer's recommended tool (eg, a tension gauge).
   • Measure according to the tool and conveyor manufacturer's instructions.
   • Typical tension values can vary from a few kilonewtons to tens of kilonewtons, depending on belt width, belt type and conveyor length.

5. Tension adjustment (if necessary):

   • For screw tensioning stations: Loosen the lock nuts and carefully tighten/unscrew the adjusting screws, evenly on both sides, to achieve the desired tension. Adjust in increments of no more than 1-2 revolutions of the screw at a time.
   • For counterweight tension stations: Check the number and mass of counterweights. Add or remove counterweights to adjust tension. Check the free movement of the counterweight.
   • Common mistake: Uneven adjustment of the screw tension station on both sides, which leads to a skew of the tension drum and, accordingly, to a displacement of the tape.

6. Recheck: After adjustment, run the conveyor again (without material) and repeat the tension measurement. Check the centering of the tape (see 5.1).

7. Visual indicator of correctness: The tape does not slip on the drive drum, there are no excessive vibrations, the sagging of the tape on the lower branch is within acceptable limits.

5.4. Replacement of conveyor rollers

Worn or jammed rollers create increased resistance to belt movement, increase energy consumption, cause belt damage and can cause ignition due to overheating.

1. Safety:

   • Turn off conveyor power and perform LOTO procedures.
   • Make sure all moving parts are locked.
   • Use safe work platforms and fall protection when replacing rollers located high up.
   • CAUTION: Hot surfaces! Jammed roller bearings can be very hot (temperature can exceed 100°C). Use thermal gloves and an IR thermometer to check the temperature before contact.

2. Definition of defective rollers:

   • During the pre-start inspection or with the help of an IR thermometer, rollers with increased heating (> 50°C from the ambient temperature), extraneous noises (creaking, grinding) or which do not rotate are detected.
   • Visually inspect the surface of the roller for deformation, wear, deep cuts or peeling of the rubber coating (if any).

3. Dismantling a defective roller:

   • Loosen the fixing bolts of the roller support on which the roller is located. These are usually two bolts on each side.
   • Depending on the design of the roller support, it may be necessary to remove the entire support or only the roller axis.
   • Carefully remove the damaged roller. In the case of jamming, it may be necessary to use light blows of a hammer (through the gasket) or a puller.
   • A common mistake: Forceful disassembly without first loosening the fasteners, which can damage the conveyor frame.

4. Installing a new roller:

   • Before installing a new roller, check its free rotation and absence of defects.
   • Clean the seats on the roller support from dirt and rust.
   • Install the new roller in the roller support. Make sure it is installed correctly and rotates freely.
   • Install the roller support in place (if it was removed).
   • Align the roller/roller support so that it is perpendicular to the axis of motion of the belt (using a square or tape measure). Allowable deviation: no more than 1 mm per 1 meter of tape width.
   • Tighten the mounting bolts with a torque wrench to a torque of 120-150 Nm for M16 bolts or 200-250 Nm for M20. It is important to tighten evenly.
   • Common error: Incorrect alignment of the new reel, causing the tape to shift.

5. Lubrication Check:

   • If the rollers have grease nipples, lubricate the bearings according to the manufacturer's instructions, using the recommended type of grease (for example, NLGI 2 lithium grease). Do not pump the oil to avoid damaging the seals.

6. Visual indicator of correctness: The new roller is installed evenly, it rotates freely, there are no distortions. After starting the conveyor, the belt passes over it without displacement and extraneous noise. The temperature of the roller after work does not exceed the permissible values.

6. Checklist after maintenance

After completing all maintenance work, it is necessary to check the functioning of the conveyor.

7. Troubleshooting guide

8. Recommended maintenance schedule

The schedule is indicative and may be adjusted according to the intensity of operation, type of material, environmental conditions and recommendations of the conveyor manufacturer. All works must comply with DSTU EN 15232.

9. Directory of spare parts

The use of original or certified spare parts is a guarantee of reliable operation of conveyor equipment and compliance with CE and UkrSEPRO requirements. Please refer to UNITEC-D E-Catalog to order.

Please refer to our UNITEC-D Electronic Catalog for detailed information on spare parts and ordering.

10. Links

• DSTU EN ISO 14118:2016 Machine safety. Prevention of unexpected start.
• DSTU EN 166:2017 Means of individual eye protection. Technical conditions.
• DSTU EN ISO 20345:2019 Personal protective equipment. Protective shoes.
• DSTU EN 397:2017 Industrial protective helmets.
• DSTU EN 149:2019 Personal protective equipment for respiratory organs. Filter half-masks for protection against particles.
• DSTU EN ISO 5048-1:2012 Belt conveyors of continuous action for bulk materials. Part 1: General rules of calculation and design.
• DSTU EN 15232-1:2017 Energy efficiency of buildings. The impact of building automation, building management and control. Part 1: IT module.
• Instructions for operation and maintenance from the conveyor manufacturer.
• Internal standards of the enterprise on occupational health and safety.