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How to design the transmission belt more rationally

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Update time : 2022-11-14 16:42:52
Principles of Design
In the design process of the long distance belt conveyor, in line with the principle of improving the reliability of equipment and reducing the project cost, while considering the terrain conditions, installation difficulty, maintenance operability, power supply and water supply arrangement, civil engineering and other factors, the long distance belt conveyor is mainly arranged along the gentle terrain of the river valley. Along the way, avoid villages and towns, existing buildings, steep hills, waters and areas with poor geological conditions as much as possible. Meanwhile, reduce the occupation of cultivated land as much as possible and do not damage the local ecological environment.
 
Most of the conveyor system adopts the form of steel structure overhead trestle, which crosses the valley, highway, river and other facilities along the way. The overhead height meets the requirements of the limit stipulated by the state, and does not affect the construction of the original facilities and road traffic. The belt conveyor is sealed with color steel plate throughout the whole process, and the whole material is not exposed to transport, which is not affected by rain, wind, snow and other climatic conditions, so as to avoid dust and noise pollution. The transmission system is equipped with transfer station, drive station house and substation, as close as possible to the highway and near the intersection with the existing highway, convenient installation and transportation and daily maintenance.
 
 
 
Key Points of Design
2.1 Choose reasonable buffer receiving device
 
The service life of the belt of the long distance belt conveyor needs to be guaranteed by measures to reduce the impact and wear of the belt is the main measure. The belt conveyor bears a large impact at the material point, so reasonable technology and method should be adopted in the design to reduce the impact on the belt. In addition to reducing the blanking height difference, reasonable buffer facilities should be selected. At present, the most advanced and suitable is the integral buffer receiving device with supporting plate, which combines the advantages of the buffer roller and the buffer press.
 
Generally, the spacing of the buffer roller is about 400 mm, and the belt is suspended between the two buffer rollers. At this time, the impact of the material will cause great damage to the belt, especially the material with large lumpiness and sharp edges or sharp foreign bodies (iron, lining, etc.). Once it falls on the belt between the two rollers, the belt will penetrate and cut. If not handled in time, the whole tape will be split into two, which is fatal to the destruction of large steel rope core tape. For this reason, a rigid supporting plate is designed between each buffer roller. During normal operation, the rubber belt does not contact with the supporting plate. Once large materials and foreign bodies impact the rubber belt, the rubber belt will contact with the rigid supporting plate after deformation due to the force.

2. The tube formation and expansion of the tubular belt must meet the progressive principle
 
The transition section of the conveyor belt from flat to round should meet the principle of gradualism. The length of the ITD is mainly determined by the allowable elongation of the conveyor belt and the requirement that the material be gradually rolled into the range of the round tube. The conveyor belt in the transition section changes from flat shape to round pipe, and the edge of the belt will produce large additional deformation. The extension strain of the edge can be calculated similar to that of the transition section of a trough conveyor. Generally, the length of the transition section can be 25 times of the diameter of the round pipe.
 
 
3. Suitable conveyor belt cleaning device should be selected
 
Usually, the cleaning facilities used for belt conveyor mainly include scraper cleaning device, roller cleaning device, brush cleaning device, vibration cleaning device, water spray and wiper cleaning device. You can choose according to the actual situation.
 
4. Rotation of conveyor belt
 
The turning cleaning of the conveyor belt is the fundamental measure to prevent the clogging of the lower space of the conveyor belt and the adhesion of materials to the idlers. In this method, the return conveyor belt of the conveyor terminal is turned over 180° with the help of the guide roller, and the return empty side is in contact with the lower roller with a clean side, which can avoid material adhesion to the roller and the dropping of adhesive material along the conveyor line, reduce the wear of the conveyor belt and the roller, and improve the utilization rate of the conveyor belt covering layer.
The setting of the tape turning device can ensure that the bearing edge of the tape is always on the top, so as to avoid pollution along the conveying line caused by shaking off the adhesive material on the tape during operation. The other is to reduce the wear between the belt bearing surface and the return roller, so as to extend the service life of the roller and the belt. While prolonging the service life of the tape equipment, it can also reduce the power consumption, reflecting the design concept of energy saving and consumption reduction.
The main turning methods of conveyor belt are: free turning, forced turning, directional turning and tubular turning. The first two are applicable to the conveyor belt with narrow bandwidth, and the last two are applicable to the conveyor belt with any bandwidth, and are widely used in long-distance belt conveyors.
According to the different strength of the conveyor belt, the turning length of the canvas core conveyor belt is 8~12 times of the bandwidth, and the turning length of the steel rope core conveyor belt is 15~25 times of the bandwidth.

5. Choose the necessary mechanical and electrical protection devices
 
The belt conveyor operates normally under the protection of the electromechanical protection device, and protects the main parts of the conveyor in case of an accident.
(1) Protection device to prevent deviation. For the long distance belt conveyor, in addition to the setting of the aligning trusteing group and the reasonable arrangement of the forward side roller, the appropriate number of automatic deviation adjustment devices should be selected according to the length of the belt conveyor and the overall arrangement. With the development of belt conveyor technology, there are various automatic deviation adjustment devices, and the most suitable automatic deviation adjustment device can be selected according to its cost and use effect [2].
(2) with speed detection protection device. Optical encoder is preferred for belt speed detection of long distance belt conveyor. The speed protection device can be speed measuring generator type protection device, magnetic induction transmitter type protection device or proximity switch type speed protection device.
(3) Broken belt protection device. In order to prevent the slide after the conveyor belt is pulled off, it is necessary to set the catcher to protect the belt from breaking. The selection of the catcher should respond quickly, and the braking time and distance should be as short as possible. In addition, in the normal operation of the conveyor does not wear the conveyor belt, does not produce additional resistance, does not reduce the productivity of the conveyor. The reliability of the catcher is not affected by the degree of material filling and the Angle of conveyor installation. The most commonly used are wedge traps and roller traps.
(4) Metal debris detection and removal device. At present, the main use of metal detectors and iron removal devices. The iron removal device has belt iron removal device and hanging electromagnetic iron removal device.
(5) Longitudinal tear protection device. The anti-tear protection device of the conveyor belt has two detection methods: the detection of external changes of the conveyor belt after tearing and the detection of internal state changes.
 
6. Arrange plane turns reasonably according to the topography
 
For the long distance belt conveyor, plane turning is essential according to the terrain and the distribution of obstacles. The core of plane turning design is the design of tension and turning measures. Design points have the following aspects:
(1) Conveyor line design, according to the terrain conditions of the equipment layout preliminary design of the curvature radius of the curve section of the conveyor;
(2) Preliminary selection of turning measures and corresponding parameters of idlers. Groove Angle of idlers should be 25°~55°, elevation Angle of inner curve should be less than 5°, tilt Angle of supporting rod should be 1°~2°, and tilt Angle of supporting roller should be designed into forward layout of two side idlers, so as to prevent deviation of conveyor belt;
(3) Calculate the tension of each point, and calculate the resistance of the bending section and the tension of the bending section in the turning section;
(4) Check the turning limits of the bending section;
(5) Belt conveyors are generally used for conveying materials in long distance trunk lines, to carry out a detailed dynamic analysis, and use the results to further check the turning restrictions;
(6) Additional protection measures to ensure the turning operation of the conveyor.


7. Choose reasonable energy-saving driving device
 
The driving device of belt conveyor not only meets the normal operation function of daily, but also meets the requirements of energy saving. The driving design of the long distance belt conveyor is mainly considered from the following aspects:
(1) The driving device should have good starting ability and large starting torque to enable the conveyor to start with load;
(2) In the startup process, the acceleration is small and reasonable enough to reduce the dynamic load of each bearing component.
(3) Multi-motor drive can make the load of each motor uniform;
(4) Reliable overload protection ability during startup and stable operation;
(5) The driving device has a good controllability, control the start, stop speed, acceleration and deceleration speed;
(6) As far as possible to make the motor no-load start, stagger the start time of each motor, reduce the motor start times, can be stopped in a short time when the conveyor does not need to stop the motor;
(7) The driving device shall include a controller with self-monitoring and self-diagnosis functions;
(8) Use controlled start/stop transmission as far as possible
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Rules for safe operation of belt conveyors Rules for safe operation of belt conveyors
Feb .08.2023
Conditions for belt conveyor operators:
You have to have professional training to get on the job. Be familiar with the structure, performance, working principle, communication and control integrated system principle and inspection test method of the belt conveyor used, be able to maintain the belt conveyor, and be able to correctly deal with general faults.
Belt conveyor operation process:
1, in the operation of the operator is strictly prohibited to take the belt conveyor, when in use is not allowed to use the belt conveyor to transport equipment and heavy materials.
2. Check the good condition and fastening condition of all parts before operation, and confirm that there is no problem before formal operation.
3, the belt conveyor motor and switch within 20 meters near the gas concentration in the air reaches 1.5%, must stop working. Cut off power and evacuate personnel.
Belt conveyor equipment maintenance:
1. When the maintenance head is unloading the roller part, the upper mouth of the coal bunker must be strictly blocked.
2. When the belt conveyor is running, it is forbidden to clean the floating coal near the head and tail roller.
3, in the belt conveyor maintenance, troubleshooting or do other work, must close the conveyor control switch, hang up the warning sign, and press the emergency stop button.
4. When dealing with conveyor belt deviation, it is strictly prohibited to contact conveyor belt directly with hands, feet and other parts of the body.
5, often check the belt conveyor tunnel fire and spray dust removal facilities, and keep in good condition.
Safe operation rules of belt conveyor:
1, fixed conveyor should be installed on a fixed basis according to the prescribed installation method. Before the mobile conveyor is officially put into operation,  the wheels should be wedged with triangular wood or braked with brakes. In order to avoid walking in the work, there are multiple conveyor parallel operation, between the machine and the machine, between the machine and the wall should be one meter channel.
2. Before the belt conveyor is used, it is necessary to check whether each running part, belt buckle and bearing device are normal, and whether the protective equipment is complete. The tension of the tape must be adjusted to the right degree before starting.
3, the belt conveyor should be no-load start. Wait for normal operation before feeding. No feeding before driving.
4. When several conveyors run in series, they should start from the unloading end and start in sequence. After all the normal operation, can be put into the material.
5, in the operation of the belt deviation phenomenon, should stop the adjustment, not reluctantly use, so as to avoid wear edge and increase the load.
6. The working environment and the temperature of the material to be delivered shall not be higher than 50℃ or lower than -10℃.
7. No pedestrians or passengers on the conveyor belt.
8. Stop feeding before stopping, and wait for unloading of material on the belt before stopping.
9, belt conveyor motor must be well insulated. Do not pull on the mobile conveyor cable. The motor should be grounded reliably.
10. It is strictly prohibited to pull the belt by hand when the belt slips, so as to avoid accidents.
Large dip Angle conveyor anticorrosive coating requirements Large dip Angle conveyor anticorrosive coating requirements
Feb .08.2023
Large dip Angle belt machine coating requirements for anti-corrosion coating suitable for cold climate environment, winter should meet the requirements of cold and anti-freezing.
1. Surface treatment requirements
1) The surface of the steel structure of the belt conveyor shall be sandblasted to meet the national standard Sa2.5 level, remove dust, remove oil stains with cleaning agent, keep the bottom surface clean and dry, and then spray anti-rust paint. (The abrasive used is dry quartz sand with a particle size of 0.3 ~ 1.5mm).
2) Welding slag, powder coating, arc dust, residual edge and burr from mechanical processing are not allowed on the surface of welded structural parts.
3) Casting, forging surface uneven or other surface concealer caused by sandblasting to try to smooth, fill or appropriate treatment.
4) The surface of the coating to be recoated should be kept clean, dry and free of any dirt.
5) Where the processing or welding primer is damaged, it should be repainted after the primer, and then the matching medium coat or top coat.
2. Large dip Angle belt machine anticorrosive coating requirements
1.1 Paint film thickness:
Primer: epoxy zinc-rich primer, airless spray, 50μm, recoating interval 2h;
Medium coating: epoxy cloud iron antirust paint, airless spray, 100μm, recoating interval of 10h;
Top coat: acrylic rubber top coat, airless spray, 50μm, recoating interval 4h.
1.2 Requirements:
1) The interval between the metal surface after rust removal and the primer is generally no more than 6h. If rust has been rusted before painting, it should be cleaned or cleaned again.
2) Local airless spraying can not be used, brush coating can be used, brush coating (can be multiple times) film thickness must reach the specified film thickness.
3: corrosion prevention standards
1) The anticorrosion grade of the anticorrosion system shall be above medium, and the thickness of the dry film of the coating shall reach the thickness specified in this Agreement.
2) Preservative life: 5 ~ 8 years.
4: Acceptance standard
1) After surface treatment, the steel surface is almost white, no visible grease, dirt, oxide skin, rust and other sundries.
2) After coating epoxy zinc-rich primer, the standard film thickness is 50μm, the film adhesion is good, no leakage coating, pinhole, bubble, crack, fall off, flow hanging and other defects, the surface is kept dry and clean.
3) After coating the epoxy cloud iron anti-rust paint, the standard film thickness is 100μm, the adhesion between the coatings is good, no leakage coating, pinhole, bubble, crack, fall off, flow hanging and other defects, the surface is kept dry and clean.
4) After coating acrylic top paint, reach the standard film thickness: indoor 100μm, outdoor 200μm, good adhesion between coatings, no color infiltration phenomenon, no bubbles on the surface, flow hanging and other defects, the surface has a certain luster.
5. Detection method
1) Testing instrument: electromagnetic dry film thickness measuring instrument.
2) Detection method: The electromagnetic dry film thickness measuring instrument is used to measure one point every 10m2 and one point every 3 ~ 4m of thin bodies such as pipes. The three-point average is the actual film thickness of the coating, and the three-point error should be less than 20% of the specified standard film thickness.
3) Appearance detection: the appearance of the coating can be observed with the naked eye or a five-fold magnifying glass.
4) The film thickness mentioned above is dry film thickness.
Belt conveyor 6 parts installation requirements and maintenance points Belt conveyor 6 parts installation requirements and maintenance points
Feb .07.2023
The belt conveyor has the advantages of simple structure and large conveying capacity, and is widely used in mining, metallurgy and other fields. Improve the reliability and stability of belt conveyor mainly from the equipment installation and operation maintenance.
1. Structure of belt conveyor Common belt conveyor structure is mainly composed of driving device, roller, tensioning device, brake device, conveyor belt and roller and other parts. The driving device includes a driving drum, a reducer, a motor and a brake. Reducer from the structure of the form of the main points of direct axis and parallel axis reducer.
2. The belt conveyor installation sequence measurement and setting out → foundation acceptance → nose equipment transportation → tensioning device transportation → middle frame transportation → tail transportation → nose equipment installation and alignment → tensioning device installation and alignment → middle frame installation → tail installation → belt vulcan display → single machine trial operation → trial operation.
3. Installation technical requirements of belt conveyor
1) Installation of conveyor belt
Conveyor belt is the main component of belt conveyor, through the whole length of the belt conveyor. Reducing the failure rate of conveyor belt is an important method to improve the life of belt conveyor and reduce the running cost.
In the process of conveyor belt installation, to ensure the quality of conveyor belt joint must be flat, non-adhesive, non-bubbling, cohesive, smooth; The noncoincidence degree of the center line of the two rolls conveyor belt is less than 3mm. During the operation of the belt machine, the conveyor belt shall not slip or run off, and the amount of run off shall not exceed 5% of the bandwidth.
2) Installation of driving device
The driving device provides traction when the belt conveyor runs normally, and is the core of the belt conveyor.
When the driving device is installed, it is necessary to ensure that the center line of the belt conveyor is perpendicular to the axis of the driving drum, and in the center line of the width of the driving drum; Ensure that the levelness of the driving drum and the steering drum shaft should not exceed 0.3‰, the non-coincidence degree between the width center line of the driving drum and the width center line of the reversing drum and the longitudinal center line of the belt conveyor is not more than 2mm, and the non-perpendicularity between the axis line of the driving drum and the reversing drum and the longitudinal center line of the belt conveyor is not more than 2‰ of the drum width.
When the driving device is installed and adjusted, ensure that the motor has no abnormal sound, no abnormal heating and vibration; There is no abnormal sound and vibration phenomenon during the test run of the reducer, the box surface temperature is not beyond the standard, the tooth surface is not excessive wear, the fastening bolt is not loose; The brake and the backstop have no abnormal sound and heating phenomenon, and the rotating pin shaft is not stuck or abnormal wear.
3) Installation of idlers and racks
The roller is installed on the frame to support the conveyor belt, so that the overhang of the conveyor belt does not exceed the specified requirements. The roller is required to rotate flexibly and perpendicular to the center line of the belt conveyor, and the roller has no abnormal sound and stuck phenomenon. The center line of the frame and the longitudinal center line of the belt conveyor do not overlap more than 3mm; The relative height difference between the two channels of steel on the rack is not more than 3mm.
4) Installation of tension device
The tension device can compensate the elastic and plastic deformation of the conveyor belt, so that the conveyor has enough tension to prevent the belt conveyor from slipping. The rope of the tensioning device shall not rust and break the wire, and the conveyor belt shall not be relaxed. As far as possible, it is installed on the no-load branch near the driving drum, which is conducive to starting and braking without skid phenomenon; Try to install in the conveyor belt tension minimum place, so as to reduce the tension.
5) Installation of protection devices
The anti-skid protection device is installed on the return belt of the belt conveyor. For the fixed belt conveyor, the anti-skid protection device is installed between the head unloading roller and the driving roller; The pile protection shall be installed at the lap joint of two belt conveyors. The protective contact shall be hung in front of the unloading roller, and the hanging height of the protective contact shall not be higher than the lower edge of the unloading roller; The running off protection is installed in pairs, and the head and tail of the machine are installed in one group, and fixed on the belt conveyor frame using a special bracket; The temperature sensor shall be installed near the driving drum of the belt conveyor, and the temperature probe shall be close to the outer wall of the main drum.
6) Multiple belt conveyor lap installation
When multiple belt conveyors are bonded, the material falls from the unloading place of the previous belt conveyor to the receiving place of the rear belt conveyor. When the belt conveyor is installed, the drop between the unloading drum of the former belt conveyor and the rear belt conveyor should be kept at about 1m. Ensure that the material can be smoothly unloaded to the receiving belt conveyor, without too much impact.
4. Maintenance of the belt conveyor The workplace of the belt conveyor shall be kept clean to ensure that the motor, hydraulic coupler and reducer have good heat dissipation conditions; In the running process of belt conveyor, try to avoid frequent start; Before working, we should carefully check whether the hydraulic coupler leaks oil, whether the steel wire rope loosens, and whether the conveyor belt runs off. Large materials are not allowed to be loaded directly, so as not to damage the conveyor belt. Regular maintenance of belt conveyor is conducive to improving the service life of belt conveyor and reducing the failure rate of belt conveyor. Ensure the belt conveyor idler seal ring filled with grease, idler rotation flexible; Reducer, hydraulic coupling and other devices do not leak oil; Regularly check whether the fastening parts are firm and reliable; Check conveyor belt joints regularly, and repair or replace them in time.
The early installation is the basis of the stable operation of the belt conveyor, should strictly implement the installation technical requirements, from the source of hidden dangers. Maintenance is the guarantee of stable operation of belt conveyor. Therefore, it is necessary to strictly grasp the overhaul system and overhaul workers' business skills to prevent the failure of belt conveyor.
Analysis of main structure composition and abnormal problems of belt conveyor Analysis of main structure composition and abnormal problems of belt conveyor
Feb .07.2023
Belt conveyor is mainly composed of frame, conveyor belt, belt roller, tensioning device, transmission device and so on. Belt conveyor is a kind of common machinery in production and life, because of its conveying capacity, relatively small power consumption, can adapt to a variety of materials and other advantages, it is widely used.
Installation sequence of belt conveyor:
Before the belt conveyor installation needs to do a good job of organization and technical disclosure. Specifically: establish a reasonable installation management organization, clarify the responsibilities of relevant responsible personnel; Do a good job of technical disclosure, such as construction, drawing design, operating specifications and acceptance standards; Provide technical training on the use, transportation and installation of related equipment to ensure the installation quality.
The installation sequence of the belt conveyor is as follows: preparation before installation → measuring and setting out to determine the location and Angle of the belt conveyor → acceptance of roadway foundation → transportation of the head, tensioning equipment, intermediate support, tail and other equipment → head installation and alignment → tensioning device installation and alignment → middle support installation → tail installation → belt laying and connecting → commissioning → trial run.
Analysis and treatment of abnormal noise problem and belt slip:
Noise caused by idlers deviating from the center. Belt conveyor in the process of running, the roller is easy to appear noise device, and will be accompanied by periodic vibration. On the one hand, the noise is due to the uneven thickness of the seamless steel tube wall in the process of manufacturing idlers, which makes the idlers produce relatively large centrifugal force. On the other hand, because in the process of processing the idlers, there is a large deviation between the middle of the bearing holes at both ends and the center of the outer circle, which will also produce relatively large centrifugal force, resulting in abnormal noise. To deal with the problem of abnormal noise, first check the bearing of the belt conveyor, if the bearing is damaged, then replace the bearing, if the bearing is not damaged, then take other ways to deal with it.
For the shaft of the coupling caused by different noise problems, the position of the motor reducer can be adjusted accordingly to solve.
For the abnormal noise problems brought by the drum, it is generally caused by bearing damage, so the replacement of bearings can be done. For the belt slip phenomenon, if it is the hammer tension belt machine slip. You can add counterweight until the belt does not slip, but it needs to be noted that the addition can not be too much so as to avoid too much tension but affect the service life of the belt. If it is spiral tension or hydraulic tension belt machine slip problem. The tension force of the belt can be increased by adjusting the tension stroke. It should be noted that this treatment may cause deformation of the belt. When this problem occurs, the deformed belt can be cut off for subsequent operations.